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101.
A survey of genotypic responses to beneficial bacterium (Pseudomonas sp. strain PsJN) was conductedin vitro andex vitro, under two temperature conditions, using eighteen clones of potato of different heat stress tolerance: temperate adapted cultivars Kennebec and Russet Burbank; heat tolerant DTO-2, DTO-28, DTO-33, LT-1, LT-2, LT-5, LT-6, LT-7, LT-8, LT-9, Y84-02, NDD277-2, Désirée, and Maine-47; and heat sensitive abscissic acid (ABA)-deficient mutants 11401-01 and 9120-05. Nodal explants taken from 6-week-old bacterized and non-bacterized control plantlets were culturedin vitro on a hormone-free potato nodal cutting medium, and placed at either 20/15 C or 33/25 C day/night temperature, 12h photoperiod and 250 µE m?2 s?1 mixture of fluorescent and incandescent light, for six weeks. The tuberization response was studiedex vitro after two weeks acclimation of 2-week old plantlets at 33/25C. The acclimated plantlets were transplanted to 3L plastic nursery pots containing peat-based Pro-Mix growing medium and placed in growth chambers at either 20/15 or 33/25 C day/night temperature, 12 h photoperiod, 475 μE m?2 s?1 light and ≈80% RH, for 12 weeks. Compared to the non-bacterized controls, bacterization significantly increased stem length of 12, shoot biomass of 9, and root biomass of 2 clones at 20/15C; and stem length of 14, shoot biomass of 15, and root biomass of 13 clones at 33/25C. High temperature increased length of internodes and had either no effect or slightly decreased node number. Temperature increase had the most dramatic effect on root development. An average shoot to root ratio decreased from 3.7 at 20/15 C to 1.7 at 33/25 C for non-bacterized plantlets and, respectively, from 4.3 to 1.5 for bacterized. The beneficial effect of bacterization on root biomass was the most pronounced in LT-1 and Maine-47 at 20/15 C and LT-8, Maine 47, DTO-2, Kennebec, NDD277-2 and 11401-01 at 33/25C. The temperature elevation did not significantly affect root biomass of LT-6, DTO-28 and Désirée. Temperature stress caused severe reduction in tuber number and tuber fresh weight. ABA-deficient mutants did not produce any tubers and LT-8, LT-9, Y84-027 and DTO-28 tuberized very poorly at 33/25C. DTO-33, Désirée, LT-1 and Kennebec gave the highest number of tubers per pot and Kennebec, LT-1, Désirée and LT-7 the highest yields at this temperature. There was no significant effect of bacterization on tuberization at 20/15 C but at 33/25 C bacterization significantly enhanced tuber number and weight in LT-7 and reduced tuber weight in DTO-2. Although there was no clear link between thein vitro response of particular clones to bacterization and their heat stress tolerance, improvement ofex vitro performance of heat tolerant LT-7 indicates that rhizosphere bacteria may play a role in clonal adaptation of potato to heat stress.  相似文献   
102.
Individual size, size variability, cannibalism, total mortality and biomass production were studied in Clarias gariepinus in two experiments. In the Experiment 1st (duration 7 weeks) larvae originated from three females 1, 2 and 4 years old (females A, B and C, respectively). Three sibling (AA, BB and CC) and three mixed (AB, AC and BC, 1:1) larval groups were reared at a 12L:12D, 50 lux light regime. Initial individual weight of larvae in the sibling groups was strongly positively related to female age, this was preserved during 7 weeks of rearing. Initial coefficient of variation for weight was moderate in the sibling groups from young females AA and BB (30-33%), whereas it was elevated in the mixed groups (48-79%), especially in the group AC. Cannibalism was the major component of total mortality. Cannibalism in progeny of young females AA, AB and BB was reduced compared to the groups BC, AC and CC. Final biomass of small larvae issued from young females was higher than the final biomass of large progeny of the oldest female because of reduced cannibalism in the former. In a 6 week Experiment 2nd progeny of one female was reared at three light regimes: L (continuous light, 400 lux), N (“normal” 12L:12D, 50 lux) and D (continuous darkness). The final individual weight of fish was the lowest in the L group, highest in the D group, and intermediate in the N group. Final coefficient of variation for weight, cannibalism and total mortality were significantly reduced by light restrictions. The resulting final biomass was the lowest in the L group, intermediate in the N group and the highest in the D group in which it was higher by a factor 3.8 compared to the L group. Based on the results of present work and on literature overview several pathways were identified along which biomass size may be modified in populations of young fish that exhibit cannibalistic propensity. Selection of young female spawners of uniform age, and light restrictions, are recommended to mitigate cannibalism.  相似文献   
103.
104.
Deodorization of swine manure using minced horseradish roots and peroxides   总被引:1,自引:0,他引:1  
Public concerns about offensive odors from livestock manures are on the rise and so is the pressure to develop practical ways to reduce the odors. The use of minced horseradish (Armoracia rusticanaL) roots (1:10 w/v plant tissue to swine slurry ratio), with calcium peroxide (CaO2 at 26 or 34 mM) or hydrogen peroxide (H2O2 at 34, 52, or 68 mM) for the deodorization of swine manure, was evaluated through a series of laboratory experiments. The principle underlying this deodorization method is the oxidation of odorants by the concerted action of horseradish peroxidase (present in the plant tissue) and peroxide that serves as an electron acceptor, followed by polymerization of phenolic odorants with a possible copolymerization or adsorption of other odorant compounds. The deodorization effect was assessed by a human panel and gas chromatography (GC). In the case of the GC method, 12 compounds commonly associated with malodor (7 volatile fatty acids or VFAs, 3 phenolic compounds, and 2 indolic compounds) were used as odor indicators. Malodor assessment of the treated slurry by a human panel indicated a 50% reduction in odor intensity. GC results showed 100% removal of all phenolic odorants without reoccurrence for at least 72 h. In view of these data, using plant materials as enzyme carriers and peroxides as electron acceptors emerges as an effective approach to phenolic odor control in animal manure.  相似文献   
105.
The organic fraction of municipal wastes has been composted on the laboratory scale. In the obtained compost the content of cadmium, cobalt, copper, manganese, nickel, lead and zinc were determined, as well as the speciation i.e, the form of their occurrence, making use of Rudd's method of sequential extraction. The investigations also concerned the way of removing these metals from the compost by means of leaching with solutions of sulphuric and nitric acid, as well as by electrochemically separating the metals from the solution after the compost had been leached with sulphuric acid. It has been found that the application of the electrochemical method with varying pH values of the leaching solution within the range of 6.8–2.8 allows for the separation of 83.5% Cd, 55.0% Co, 65.4% Cu, 59.4% Mn, 70.3% Ni, 90.5% Pb and 56.2% Zn.  相似文献   
106.

Background

The development of cell pattern in the surface cell layer of the shoot apex can be investigated in vivo by use of a time-lapse confocal images, showing naked meristem in 3D in successive times. However, how this layer is originated from apical initials and develops as a result of growth and divisions of their descendants, remains unknown. This is an open area for computer modelling. A method to generate the surface cell layer is presented on the example of the 3D paraboloidal shoot apical dome. In the used model the layer originates from three apical initials that meet at the dome summit and develops through growth and cell divisions under the isotropic surface growth, defined by the growth tensor. The cells, which are described by polyhedrons, divide anticlinally with the smallest division plane that passes depending on the used mode through the cell center, or the point found randomly near this center. The formation of the surface cell pattern is described with the attention being paid to activity of the apical initials and fates of their descendants.

Results

The computer generated surface layer that included about 350 cells required about 1200 divisions of the apical initials and their derivatives. The derivatives were arranged into three more or less equal clonal sectors composed of cellular clones at different age. Each apical initial renewed itself 7–8 times to produce the sector. In the shape and location and the cellular clones the following divisions of the initial were manifested. The application of the random factor resulted in more realistic cell pattern in comparison to the pure mode. The cell divisions were analyzed statistically on the top view. When all of the division walls were considered, their angular distribution was uniform, whereas in the distribution that was limited to apical initials only, some preferences related to their arrangement at the dome summit were observed.

Conclusions

The realistic surface cell pattern was obtained. The present method is a useful tool to generate surface cell layer, study activity of initial cells and their derivatives, and how cell expansion and division are coordinated during growth. We expect its further application to clarify the question of a number and permanence or impermanence of initial cells, and possible relationship between their shape and oriented divisions, both on the ground of the growth tensor approach.
  相似文献   
107.
Our earlier studies have shown that the compounds diphenyltin dichloride (DPhT) and triphenyltin chloride (TPhT) in the presence of UVC radiation enhanced the degree of phosphatidylcholine liposome membrane oxidation (J. Agric. Food Chem. 2005, 53, 76-83). The prooxidative behavior of the compounds has now been confirmed with the electron paramagnetic resonance method, which proved the possibility that the studied compounds can exist in free radical forms. The present work investigates the possibility of the protective action of quercetin on phosphatidylcholine liposome membranes exposed to the prooxidative action of DPhT and TPhT induced by UV radiation (lambda = 253.7 nm). The concentrations of quercetin and its equimolar mixtures with DPhT and TPhT were determined (and compared with well-known antioxidants as standards-trolox and butylated hydroxytoluene, also in the presence of phenyltins) as those that induce 50% inhibition in oxidation of liposomes radiated with UV. They are 5.1 +/- 0.10, 2.9 +/- 0.12, and 1.9 +/- 0.08 microM (differences between the values are statistically significant), constituting the following sequence of antioxidative activity: quercetin:TPhT > quercetin:DPhT > quercetin. This relation is confirmed by the results on the antiradical ability of quercetin and its mixtures with DPhT and TPhT toward the free radical 1,1-diphenyl-2-pricrylhydrazil. Similar sequences obtained in both studies suggest a possible mechanism of the antiradical action of the mixtures as free radical scavengers. We suggested that (i) quercetin's ability, documented by spectrophotometric, infrared attenuated total reflectance spectroscopy, (1)H NMR, and molecular modeling methods, to form complexes with phenyltins indicates a possible way of protection against the peroxidation caused by the free radical forms of phenyltins and (ii) the differentiation in the action of the quercetin/TPhT and quercetin/DPhT associates (statisticaly significant) may result from a different localization in the liposome membrane, which is indicated by the results of the fluorimetric studies.  相似文献   
108.
Anthocyanins, present in fruits and vegetables as natural colorants, have been well characterized to possess bioactive properties. Anthocyanin components extracted from black rice (Oryza sativa L. indica) separated by gel filtration and identified using LC-MS were cyanidin 3-glucoside and peonidin 3-glucoside. A standardized extract of black rice pigmented fraction (BRE) containing known proportions of cyanidin 3-glucoside and peonidin 3-glucoside exhibited marked antioxidant activities and free radical scavenging capacities in a battery of in vitro model systems. Significant (p < 0.05) prevention of supercoiled DNA strand scission induced by reactive oxygen species (specifically, peroxyl radical and hydroxyl radicals) and suppression of the oxidative modification of human low-density lipoprotein was obtained with BRE. In addition, BRE reduced (p < 0.05) the formation of nitric oxide by suppressing inducible nitric oxide synthase expression in murine macrophage RAW264.7 cells, without introducing cell toxicity. The results of this study show that black rice contains anthocyanin pigments with notable antioxidant and anti-inflammatory properties for potential use in nutraceutical or functional food formulations.  相似文献   
109.
The effects of Potato leafroll virus (PLRV) isolates and inoculation method on the resistance to PLRV in potato clones and cultivars were investigated. In the season of inoculation, aphid inoculation resulted in higher proportions of infected plants and higher virus concentration in infected plants, as compared to graft inoculation. In these respects, grafting showed superiority over aphid inoculation in the tuber progeny of inoculated plants, though distinct dominance of aphid inoculation was observed for some tested clones. This leads to the conclusion that both methods should be applied as complementary tests for the efficient selection of highly resistant potato clones. For inoculations, two isolates of PLRV were applied, and one of them, isolate L7, was routinely used in screening breeding materials for resistance to the virus. The second isolate originated from plants of the highly resistant clone DW84-1457, which were incidentally infected with PLRV. The virus isolated from these plants was able to infect only specific clones, which were resistant to isolate L7. At the same time, potato clones with resistance derived from a source different from that present in DW84-1457, and standard susceptible and resistant cultivars, showed generally lower infection ratings after inoculation with the new isolate. This result suggests that the isolates may be different strains of PLRV. It is possible that under the strong selection pressure of resistance genes present in clone DW84-1457, a new isolate I-1457 could evolve the ability to overcome resistance to infection controlled by these genes.  相似文献   
110.
Summary Potato leaf roll virus (PLRV) was usually better transmitted byMyzus persicae from source plants kept during the pre-acquisition period at 12°C than from those kept at 26°C. Significantly more plants became infected when PLRV was acquired or inoculated at 26°C than at 12°C. The effect of temperature during the acquisition feeding period was found to be greater than that of temperature during the inoculation feeding period. PLRV was most frequently transmitted when it was both acquired and inoculated at 26°C.
Zusammenfassung Der Einfluss der Temperatur auf die übertragung des Kartoffel-Blattrollvirus (PLRV) durchMyzus persicae wurde in drei Perioden vor der Infektion der Pflanzen mit diesem Virus ermittelt: Vegetationsperiode vor Aufnahme durch die Virusquellen, Periode w?hrend der Virusaufnahme und der Inokulationsperiode. Die Untersuchungen wurden in temperaturkonstanten Kammern und im Gew?chshaus mit Pflanzen der Kartoffelsorte Osa als Quelle mit ausgew?hlten PLRV-Isolaten durchgeführt. Das Virus wurde aufPhysalis floridana und Kartoffelsorten unterschiedlicher Anf?lligkeit übertragen. Die H?ufigkeit der PLRV-übertragung durchM. persicae sank mit ansteigender Temperatur, zu welcher die Quellenpflanzen in der Periode vor der Virusaufnahme aufwuchsen (Abb. 2 und 3), obwohl dieser Effekt ausgeschaltet werden konnte, wenn das Virus durch die Blattl?use bei h?herer Temperatur aufgenommen wurde (Abb. 2). Die H?ufigkeit der PLRV-übertragung durch Blattl?use war nach einer Aufnahmeperiode bei 26°C signifikant gr?sser als bei 12°C (Abb. 2 bis 4). Der Einfluss h?herer Temperatur k?nnte stark genug sein, die Unterschiede in der PLRV-übertragung durch den Einfluss auf die Quellenpflanzen in der Vor-Aufnahmezeit zu eliminieren oder zu vermindern (Abb. 2). ?hnliches zeigte sich bei zunehmendem Alter der Quellenpflanzen (Abb. 1). Eindeutig mehr Pflanzen wurden infiziert, wenn PLRV bei 26°C anstatt 12°C inokuliert wurde (Abb. 3 und 4). Der Einfluss der Temperatur war in der Aufnahmeperiode gr?sser als in der Inokulationsperiode. Eine signifikant gr?ssere Population vonP. floridana und/oder Kartoffelpflanzen wurden infiziert, wenn PLRV durchM. persicae bei 26°C aufgenommen und inokuliert wurde (Abb. 3 und 4). Darüberhinaus war der Einfluss h?herer Temperatur, w?hrend beider Aufnahmeperioden angewendet, günstiger für visuelle und serologische (ELISA) Differenzierung der resistenten und anf?lligen Kartoffeln, gemessen an der H?ufigkeit infizierter Pflanzen (Abb. 4).

Résumé L'influence de la température sur la transmission du virus de l'Enroulement de la pomme de terre (VEPT) parMyzus persicae a été déterminée à trois périodes précédant l'infection des plantes par ce virus: période de végétation des plantes sources de virus avant acquisition (pré-acquisition), période d'acquisition, période d'inoculation. Les recherches ont été réalisées dans des salles à température contr?lée et en serre: des pommes de terre du cultivar Osa, infectées par des isolats sélectionnés de VEPT ont été utilisées comme plantes sources. Le virus a été transmis àPhysalis floridana et à des cultivars de pomme de terre de différentes sensibilités à l'infection par le VEPT. La fréquence de transmission du VEPT parM. persicae décro?t avec l'augmentation de la température à laquelle les plantes sources de virus ont été cultivées lors de la période de pré-acquisition (Figs 2 et 3), bien que cet effet ait pu être éliminé quand le virus a été prélevé par les pucerons à température plus élevée (Fig. 2). La fréquence de transmission du VEPT par les pucerons a été significativement plus grande après une période d'acquisition à 26° qu'à 12°C (Figs 2–4). L'effet de la température la plus élevée a pu être suffisamment fort pour supprimer ou réduire les différences de transmission du VEPT causées par l'effet de la température sur les plantes sources lors de la période de pré-acquisition (Fig. 2) ou par l'augmentation de l'age des plantes sources (Fig. 1). Un nombre significativement plus grand de plantes a été infecté quand le VEPT était inoculé à 26°C qu'à 12°C (Figs 3 et 4). L'effet de la température s'est avéré avoir une importance plus grande pendant la période d'acquisition que pendant la période d'inoculation. Une proportion significativement plus élevée deP. floridana et/ou de plants de pomme de terre a été infectée quand le VEPT était à la fois acquis et inoculé parM. persicae à 26°C (Figs 3 et 4). De plus, une température plus élevée appliquée pendant les deux périodes d'alimentation des pucerons s'est montrée plus favorable pour différencier visuellement et sérologiquement (ELISA) les pommes de terre résistantes, modérément résistantes et sensibles, lorsqu'on se base sur la fréquence des plantes infectées (Fig. 4).
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