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Fusarium head blight (FHB) is an important disease of wheat, which can result in the contamination of grains with mycotoxins such as deoxynivalenol (DON). Artificial inoculation of flowering ears with conidial suspensions is widely used to study FHB diseases. Our goal was to compare four inoculation treatments in which a conidial suspension was sprayed on flowering ears and to study the effect of the application of moisture during kernel setting and filling with a mist-irrigation system. Ten wheat genotypes were inoculated with a DON-producing Fusarium culmorum strain. Inoculation treatments varied in time of application of the inoculum (morning or evening) and in the method of controlling humidity during inoculation (bagging or mist irrigation). A wet season was simulated with a mist-irrigation system, keeping the crop canopy wet for at least 26 days after flowering. The severity of FHB symptoms (area under disease progress curve (AUDPC)), yield loss and DON contamination in the grains were determined. AUDPC data obtained with the different inoculation treatments were highly correlated (r=0.85–0.95). Mist irrigation after inoculation resulted in a higher mean disease severity, but in a overall lower toxin contamination as compared to the non-irrigated treatments. Genotypic differences in DON accumulation were present: for one wheat line toxin contamination significantly increased when irrigated, while two genotypes accumulated significantly less toxin. The closest relationships (r=0.73–0.89) between the visual symptoms and the DON content were obtained under moderate mean infection pressure. This relation between visual symptoms and the DON content deteriorated at higher infection levels.  相似文献   
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1. In commercial layer breeding, extensive gene pools are tested and selected for market requirements which must be anticipated at least 5 years ahead. Field results confirm a continuous positive genetic trend in egg output and better feed efficiency which can be converted into land savings.

2. Animal welfare and cage-free housing dominate future needs of the market. Nesting behaviour and minimal tendency to develop feather-pecking or cannibalism without beak treatment are key trait complexes. Stronger shells for longer production cycles without moulting have to be combined with better bones.

3. No single big gene effect can be expected to control the multifactorial problem of feather-pecking. Adjusting the shape of the beak, with a heritability of .10–.25, can contribute to reducing the risk of severe cannibalism.

4. For better skeletal integrity, the assessment of bone quality in pedigree birds housed in enriched cages is done by keel bone palpation or ultrasound measurement of the humerus. Both traits show similar heritabilities in the range of .15–.30 and can be included in a balanced selection approach for performance, quality and welfare traits.

5. The combination of performance testing and genome-wide DNA marker analysis is a promising tool to generate more progress for a balanced performance and behaviour profile.  相似文献   

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The Mexican cichlid Cichlasoma beani is currently exploited regionally as food and can be commercialized in the aquarium trade. Natural populations of C. beani may already be negatively affected by anthropogenic alteration of the areas in which it is distributed. The aim of the present study was to examine the effect on growth, survival, and condition of C. beani cultured in three stocking densities: three (D3), six (D6), and nine (D9) fish per each 40 L tank. At the end of a 6‐wk trial the fish cultured in D3 were longer, heavier, and grew faster than the rest of the treatments but their survival was the lowest compared to D6 and D9. The mortalities were caused by a strong aggressive behavior in D3.  相似文献   
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In Israel, black spot caused by Alternaria alternata is the main postharvest factor that impairs the quality and reduces the storability of persimmon fruit (Diospyros kaki cv. Triumph). The fungus infects the fruit in the orchard and remains quiescent until harvest. After harvest, the pathogen slowly colonizes the fruit during storage at 0 °C, which elicits black spot symptom development 2–3 months after storage entry. A commercial postharvest dip treatment in chlorine at 500 mg L?1, released from sodium troclosene tablets, effectively controlled black spot in fruit stored for up to 2 months. However, decay incidence increased as the length of storage was extended beyond 2.5 months. The long incubation period that precedes black spot symptom development after harvest enabled the development of a series of integrative approaches for application at the pre- and postharvest stages, in combination with the commercial chlorine dip treatment, to improve the control of black spot disease. Preharvest treatments included treatment with the cytokinin-like N1-(2-chloro-4-pyridyl)-N3-phenylurea (CPPU) 30 d after fruit set, or a single spray with the curative fungicide polyoxin B 14 d before harvest, and when one of these was applied in combination with the postharvest chlorine dip treatment, the black spot infected area was reduced by 3 and 60%, respectively, compared with the chlorine dip alone. At the postharvest stage, fogging during storage, or post-storage on-line spraying with sodium troclosene, when applied in combination with the postharvest chlorine dip, improved the percentage of marketable fruit by 2 or 10%, respectively, compared with the chlorine dip alone. The results indicate that postharvest pathogens that show a slow colonization pattern might enable the integration of pre- and postharvest disease control methods to improve quality and reduce postharvest disease development.  相似文献   
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Compounds containing fluoro- or fluoroalkyl-substituents often show interesting biological activities. However, the high cost of introducing fluorine into a molecule may make the manufacture of a compound with excellent biological activity too expensive for commercial viability. The cheapest source of fluorine is hydrogen fluoride but most fluorine substitution reactions described in the literature make use of alkali metal fluorides which, although more convenient to handle in the laboratory, are much more expensive. This paper describes the use of hydrogen fluoride in new synthetic routes to a number of intermediates for the manufacture of commercially useful pesticides. These include compounds containing the dichlorofluoromethylsulphenyl radical, derivatives of perfluoro-2,5-diazahexa-2,4-diene, various aromatic fluoro compounds and some fluorinated benzodioxoles and benzodioxenes.  相似文献   
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The efficacy of oxolinic acid (at 200 and 300 μg a.i./l) and of several antibiotic compounds (streptomycin sulfate at 100 μg a.i./l, glycocide B at 700 μg a.i./l, kasugamycin at 80 μg a.i./l and gentamicin sulfate at 30 and 60 μg a.i./l) againstErwinia amylovora, the causal agent of fire blight in pears, was evaluated in 43 orchard experiments in 1997–2000 in Israel. In addition to the above orchard experiments, the efficacy of the bactericides was tested in live experiments with artificial inoculation. Natural fire blight symptoms were observed in 16 of the 43 experiments; in 13 of them, disease intensity and its distribution among the experimental plots provided a basis for data analysis, leading to reliable conclusions concerning the efficacy of the tested bactericides. Oxolinic acid at 300 μg a.i./l was highly effective againstE. amylovora and reduced disease severity significantly in all experiments, as compared with the untreated plots; however, a concentration of 200 μg a.i./l was not effective in some cases. Among the tested antibiotics, only gentamicin sulfate was as effective as oxolinic acid. Results of the artificial inoculation experiments corroborated those obtained in the naturally infected orchards. The pre-infection activity of oxolinic acid was determined on blossom clusters that were sprayed with the bactericide before inoculation. Control efficacy on blossom clusters sprayed 1–4 days before inoculation ranged from 68% to 80%, a level which did not differ significantly from that observed on blossom clusters sprayed on the day of inoculation (80% control). The postinfection activity of oxolinic acid was determined on blossom clusters that were sprayed with the compound after inoculation. Oxolinic acid was as effective when applied 1 or 2 days after inoculation as when it was applied on the day of inoculation; however, application of the bactericide 3 days after inoculation no longer resulted in significant disease suppression. Oxolinic acid has been used commercially in Israel since 1998 with appreciable success. Contribution No. 533-00 from the Agricultural Research Organization  相似文献   
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Growth responses and nitrogen constituents were tested in young citrus trees grown on gradually decreasing amounts of phosphorus in greenhouse solution cultures. The phosphorus concentration in dry matter of minus-P leaves dropped to a third of that in control leaves and then remained steady throughout the experiment, while the total nitrogen concentration was low at the beginning and, rising gradually, reached an enormous amount. Nitrogen estimations in minus-P leaves showed the specific dynamics of the soluble nitrogen fraction: its content was low at the onset of the deficiency, and rose rapidly due to intensive accumulation of arginine in the tissues. Under conditions of acute phosphorus deficiency, arginine constituted more than 60% of the free amino acids and arginine nitrogen above 40% of the total, while in normal leaves arginine did not exceed 8% of the free amino acids, and about 1–% of the total.Similar patterns of increased nitrogen level due to arginine accumulation were found in leaves of phosphorus-deficient grapefruit and orange trees under field conditions.  相似文献   
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