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201.
OBJECTIVE: To develop a food-frequency questionnaire (FFQ) useful for ranking of nutrient intakes. DESIGN: Subjects consuming their regular diet completed 7 days of weighed intake registry (7-WIR). Foods for the FFQ were selected by stepwise multiple regression. The FFQ was then completed for each subject using data on individual food consumption from the 7-WIR. The correlation and agreement between the extrapolated FFQ and the 7-WIR data were assessed using Spearman's rank correlation coefficients (rS) and Bland and Altman's limits of agreement (LOA). SETTING: Bucaramanga, Colombia. SUBJECTS: We studied 97 randomly selected 20-40-year-old subjects. RESULTS: Sixty foods were selected for the FFQ. The 7-WIR and the extrapolated FFQ intake estimates correlated well. rS was 0.58 for energy, 0.53 for carbohydrate, 0.50 for total fat, and 0.48 for protein. For micronutrients, rS varied from 0.46 (manganese) to 0.71 (vitamin B12). FFQ average intake estimates were 83%, 80%, 86.2% and 86.4% of 7-WIR estimates for energy, carbohydrate, total fat and protein, respectively. LOA for these nutrients ranged between 45% and 165%. FFQ micronutrient intakes were on average 96% (median) of those from the 7-WIR, and the median lower and upper LOA were 50% and 203%. However, there was no indication that the degree of agreement varied with the level of intake. CONCLUSIONS: According to our simulated validation, this FFQ may be useful to rank subjects by nutrient intake. Its validity against standard independent measurements and its applicability to other subsets of the Colombian population should be carefully considered.  相似文献   
202.
How can conservation planners optimally and effectively allocate limited resources between imminently threatened and presently secure areas? Such choices must be made at multiple spatial scales involving a variety of conservation targets. Allocation strategies range from a “fire-fighting” approach, which gives priority to heavily developed areas at high risk of further habitat loss, to a “pre-emptive” approach giving priority to intact habitat tracts before they become threatened. We determined optimal dynamic reserve selection strategies when selections are made in imminently threatened and presently secure areas that will become threatened at uncertain times in the future. The objective was to maximize the expected number of endemic species conserved, predicted with species-area curves. The model was solved for three forms of species-area curve proposed in theoretical studies of habitat loss. Alternative scenarios were considered on the relationship between land prices and development risk. For the most commonly proposed form of the species-area relationship, the fire-fighting approach is optimal even if land prices rise substantially when presently secure areas become threatened. This reflects the assumption that species decline accelerates only after a large proportion of original habitat has been lost. The possibility of large species losses at lower levels of habitat loss justifies at least some pre-emptive conservation, even if land prices are not correlated with threat. If species decline is proportional with habitat loss, the optimal conservation strategy depends strongly on land price dynamics.  相似文献   
203.
Lantibiotics are polycyclic peptides containing unusual amino acids, which have binding specificity for bacterial cells, targeting the bacterial cell wall component lipid II to form pores and thereby lyse the cells. Yet several members of these lipid II-targeted lantibiotics are too short to be able to span the lipid bilayer and cannot form pores, but somehow they maintain their antibacterial efficacy. We describe an alternative mechanism by which members of the lantibiotic family kill Gram-positive bacteria by removing lipid II from the cell division site (or septum) and thus block cell wall synthesis.  相似文献   
204.
A detailed analytical study on trichlorfon residues in selected vegetables samples has been carried out, focused on the reliable quantification and confirmation of this compound, and on stability of residues under storage. As a consequence, a rapid and sensitive LC-ESI-MS/MS method has been developed for the determination of residues of this insecticide in kaki fruit (flesh and peel) and cauliflower samples. Extraction was performed with acetonitrile using a high-speed blender. After 4-fold dilution of the extract with water, 20 microL was directly injected in the LC-ESI-MS/MS system (triple quadrupole), using matrix-matched standards calibration for quantification. Under optimized MS/MS conditions, limit of detections between 0.006 and 0.013 mg/kg were reached, and a limit of quantification of 0.05 mg/kg was established, with a runtime of only 15 min. Recoveries from spiked blank samples at 0.05 and 0.5 mg/kg were in the range 83-101% with relative standard deviations lower than 10%. The method was applied to treated and untreated samples collected from field residues trials, using quality control samples analysis for the evaluation of the method. Despite the acquisition of two MS/MS transitions in selected reaction monitoring mode, the analysis of treated samples revealed the presence of a chromatographic peak close to the analyte that corresponded to a trichlorfon isobaric compound that shared the same MS/MS transitions. This unusual situation in LC-MS/MS-based procedures required the application of an efficient chromatographic separation to avoid this interference. All experiments have been made in compliance with the principles of Good Laboratory Practices (GLP) and following the European SANCO guidelines for pesticides residue analysis (PRA).  相似文献   
205.
The longstanding assumption that calves of more than 6 months of age are more resistant to Mycobacterium avium subspecies paratuberculosis (MAP) infection has recently been challenged. In order to elucidate this, a challenge experiment was performed to evaluate age- and dose-dependent susceptibility to MAP infection in dairy calves. Fifty-six calves from MAP-negative dams were randomly allocated to 10 MAP challenge groups (5 animals per group) and a negative control group (6 calves). Calves were inoculated orally on 2 consecutive days at 5 ages: 2 weeks and 3, 6, 9 or 12 months. Within each age group 5 calves received either a high – or low – dose of 5 × 109 CFU or 5 × 107 CFU, respectively. All calves were euthanized at 17 months of age. Macroscopic and histological lesions were assessed and bacterial culture was done on numerous tissue samples. Within all 5 age groups, calves were successfully infected with either dose of MAP. Calves inoculated at < 6 months usually had more culture-positive tissue locations and higher histological lesion scores. Furthermore, those infected with a high dose had more severe scores for histologic and macroscopic lesions as well as more culture-positive tissue locations compared to calves infected with a low dose. In conclusion, calves to 1 year of age were susceptible to MAP infection and a high infection dose produced more severe lesions than a low dose.  相似文献   
206.
This research studied a novel form of distillation (high vacuum distillation) as a method for preserving volatile aroma chemicals important to the organoleptic attributes of a four botanical model gin as well as the degradation products generated during the heating required in traditional methods of gin distillation. A 2 (5) factorial experiment was conducted in a partially confounded incomplete block design and analyzed using the PROC MIXED procedure from SAS. A model gin was made of dried juniper berries (Juniperus communis), coriander seed (Coriandrum sativum), angelica root (Angelica archangelica), and dry lemon peel (Citrus limonum). This was distilled on a traditional still utilizing atmospheric pressure and a heating mantel to initiate phase separation as well as a novel still (high vacuum) utilizing high vacuum pressures below 0.1 mmHg and temperatures below -15 degrees C to initiate phase separation. The degradation products (alpha-pinene, alpha-phellandrene, E-caryophyllene, and beta-myrcene) were present at greater levels (approximately 10 times) in the traditional still-made gin as compared to the novel gin.  相似文献   
207.
Previous studies demonstrated the formation of stable phosphate-metal-humic complexes in solution. These studies, however, indicated that the proportion of complexed metal that intervenes in phosphate fixation is rather low. In this study we investigate the possible structural and electronic features of the binding site involved in phosphate fixation in metal-humic complexes that could explain this fact. To this end, we have studied phosphate-metal-humic complexes involving Fe(III), Al(III), and Zn(II) using three complementary techniques: infrared spectroscopy (FTIR), fluorescence, and molecular modeling. The FTIR study indicated that, in the case of those complexes involving Fe and Zn phosphate, fixation is associated with a stabilization of the metal-carboxylate bond. In the case of Al this effect is less clear. This effect of phosphate fixation on the characteristics of the metal-humic binding site was also supported by the results obtained in the Fluorescence study, which showed significant changes in the quenching effect normally associated with metal complexation in humic substances upon phosphate fixation. Finally, the molecular modeling study revealed that the stability of phosphate-metal-humic complexes is inversely related to the stability of the metal-humic interaction. This result could explain why only a relatively low proportion of humic complexed metal is involved in phosphate fixation.  相似文献   
208.
Inoculants are biological formulations that combine a stable microorganism population and various types of compounds produced and released during fermentation, such as phytohormones and plant growth regulators. Azospirillum brasilense strain Az39 and Brayrhizobium japonicum strain E109 were previously shown to produce indole 3-acetic acid (IAA), gibberellic acid (GA3) and zeatin (Z). We tested the hypothesis that such compounds are responsible for early growth promotion in inoculated corn (Zea mays L.) and soybean (Glycine max L.) seedlings. Seeds were inoculated with Az39, E109, or both, and kept in a chamber at 20–30 °C under a controlled photoperiod to evaluate seed germination. To evaluate root and shoot length and dry weight, and number of nodules and percentage of nodulated seedlings, in soybean, seedlings were kept in a growth chamber for 14 days under similar photoperiod and temperature conditions. Az39 and E109, singly or in combination, showed the capacity to promote seed germination, nodule formation, and early development of corn and soybean seedlings. Both strains were able to excrete IAA, GA3 and Z into the culture medium, at a concentration sufficient to produce morphological and physiological changes in young seed tissues.  相似文献   
209.
210.
Purpose: In recent years, interest in plant nutrition research has arisen with a strong focus on organic forms. The aim of this study was to determine the effect of different organic fertilizers on growth, yield, fruit quality and polyphenol content in soilless grown grape tomatoes under greenhouse conditions.

Materials and methods: Tomato plants were subjected to three organic nutrient solutions, which consisted of different mixtures of several OMRI (Organic Materials Review Institute) certified nitrogen fertilizers of industrially processed residues: Treatment I: solid and soluble liquid fertilizers of animal raw materials, natural potassium sulphate-non-synthetic, and calcium chloride; Treatment II: solid and soluble liquid fertilizers of animal raw materials, by-product of marine raw material (soluble liquid), natural potassium sulphate-non-synthetic, and calcium chloride; and Treatment III: solid fertilizers of animal raw materials, natural potassium sulphate-non-synthetic, and calcium chloride to 100% [0-30 days after transplanting (DAT)], 125% [31-80 DAT], and 150% [>81 DAT]. The Steiner solution (SS) was used as a control (Treatment IV).

Results: Yield did not differ between organic and conventional treatments, ranging from 3.04 to 3.35 kg m-2 while fresh weight in organic treatments was 3.14 compared to 3.2 kg m-2 in plants fed with the SS. No significant differences in plant height or fruit quality were found. The application of organic fertilizers positively affected the total hydrolysable and condensed polyphenols of tomato fruits compared to the control. Twelve phenolic compounds were identified, highlighting 3-Caffeoylquinic acid, salvianolic acid and 5,6-Dihydroxy-7,8,3’,4’-tetramethoxyflavone (Treatment I) and Medioresinol (Lignan) (Treatment II).

Conclusions: The results indicated that organic fertilization through animal-based fertilizer application is a feasible alternative for grape tomato production under greenhouse conditions.  相似文献   

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