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71.
This study compares both versions of the nutritional requirement system determined by the National Research Council (NRC) version 1985 (NRC85) and NRC version 2007 (NRC07), for finishing lambs in feedlots. Nineteen crossbred lambs were divided in four groups representing four experimental treatments: one diet according to NRC85 and three diets according to NRC07. The diets recommended by NRC07 considers crude protein intake relative to ruminal undegradable protein at 20, 40, and 60 % levels (NRC07/20, NRC07/40, and NRC07/60). Diets were composed of Brazilian semi-arid native grass silage, soybean meal, corn, annatto byproduct, and limestone. Purchases and sales of lambs were done according to average market prices in Brazil. The economic indicators considered pointed that all treatments were viable but NRC07/20 and NRC07/60 were more profitable with similar net present values (NPVs) and internal return rates (IRRs). NRC07/20 was the best option showing an IRR of 17.20 % and a payback period (PP) of 5.07 considering a fixed annual interest rate of 6 %. Sensitivity analysis considering a 10 % raise in variable costs showed negative NPVs, IRRs inferior to the opportunity cost rates adopted and PPs that exceeded the planning horizon of 7 years for both NRC85 and NRC07/40.  相似文献   
72.
The aim of this work was to isolate a lectin from Myracrodruon urundeuva heartwood and to evaluate its antimicrobial activity against bacteria and fungi that attack plants, including woods. The lectin was isolated from heartwood through affinity chromatography on a chitin column monitored by hemagglutination assay. The lectin inhibited Gram-negative and Gram-positive bacteria and was more effective than antifungal Cercobin in growth inhibition of phytopathogenic fungi. The detected antimicrobial activity reveals the possible role of the lectin in the resistance of M. urundeuva heartwood against deteriorative biological agents. The M. urundeuva lectin is the first bioactive peptide found in heartwood, probably stored as a chemical protection against biodegradation.  相似文献   
73.
Sugarcane is one of the crops responsible for the high consumption of fertilizers in Brazil. To minimize this demand a sustainable alternative is to increase the studies to evaluate the beneficial effects of the relationship between plants/microorganisms, mainly plant growth-promoting bacteria. The objectives of this study were: a) to evaluate potentially diazotrophic bacteria isolates from sugarcane in adverse environmental conditions; b) inoculate these bacteria in sugarcane to evaluate their ability in plant growth-promotion. The study was carried in the Northeast of Brazil. Bacterial genera Burkholderia sp., Pantoea sp., Stenotrophomonas sp. and Enterobacter sp. were evaluated in different culture medium and later the bacterial isolates were inoculated in sugarcane evaluating the plant growth-promotion. Stenotrophomonas sp. and Pantoea sp. were tolerant to salinity and to different sources of carbon in acid medium and too tolerated high concentrations of pesticides and produced quorum sensing molecules (QS), but did not increase the dry matter production of sugarcane. Burkholderia sp. and Enterobacter sp. were more sensitive to salinity and pest control, but were more effective in plant growth-promotion. The tolerance of the bacteria to the adverse environmental conditions interfered negatively in the ability to plant growth-promotion.  相似文献   
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75.
Zebrafish sperm cryopreservation is a fundamental methodology to manage and back-up valuable genetic resources like transgenic and mutant strains. Cryopreservation usually requires liquid nitrogen for storage, which is expensive and hazardous. Our objective was to evaluate if electric ultrafreezers (??150 °C) are a viable alternative for zebrafish sperm storage. Zebrafish sperm was cryopreserved in the same conditions (??20 °C/min), stored either in liquid nitrogen or in an ultrafreezer, and thawed after 1 week, 1 month, and 3 months. Sperm motility, membrane integrity, and fertilization ability were assessed. There were no significant differences in motility and hatching rate throughout storage time. Additionally, we aimed at understanding if cryopreservation directly in an ultrafreezer (??66 °C/min) could improve post-thaw sperm quality. Freezing at ??20 °C/min was performed as before, and compared to samples cryopreserved with a fast cooling rate by placing directly in an ultrafreezer (??66 °C/min). Sperm quality was assessed according to motility, viability, DNA fragmentation, and apoptosis (annexin V). The ??66 °C/min cooling rate showed significantly higher membrane and DNA integrity, and lower number of cells in late apoptosis in comparison to the other treatments. This study showed that zebrafish sperm cryopreservation and storage in an ultrafreezer system is possible and a fast cooling rate directly in ultrafreezer improves post-thaw sperm quality.  相似文献   
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77.
Araucaria angustifolia (Bertol.) O. Kuntze exhibits dimorphism in its stem structure, where the trunk is orthotropic and branches and branchlets (primary and secondary branches) are plagiotropic. These stems exhibit different behavior when used for vegetative propagation, and only segments of trunk can form a complete plant. The physiological and biochemical mechanisms that characterize these stems are still little known. The aim of this study was to describe the free amino acid profiles in trunks, branches, and branchlets of A. angustifolia. Segments of 5 cm in length were excised from young individuals below the stem apex. The needles were removed and samples were frozen and lyophilized. The determinations were made by high-performance liquid chromatography, and the results were expressed as µg/g fresh weight (FW). The trunks and branches had the highest content of total amino acids, which were 112.23 ± 20.57 µg/g FW and 111.97 ± 27.78 µg/g FW, respectively. The amino acids—glutamine, aspartate and γ-aminobutyric acid and tyrosine—were noticeably higher in the three types of stems. In the trunk, a higher amount of asparagine and tryptophan, was also detected. Glutamic acid and glutamine were found in higher quantities in the branches. The branchlets had very low total amino acid content (30.79 ± 4.19 µg/g FW), wherein asparagine is the only amino acid not detected. Thus, it was observed that the profile of the free amino acid differs among trunks, branches, and branchlets in A. angustifolia, indicating that they perform different functions.  相似文献   
78.
This review discusses the isolation, structural elucidation, and biological activities of halogenated indole alkaloids obtained from marine invertebrates. Meridianins and related compounds (variolins, psammopemmins, and aplicyanins), as well as aplysinopsins and leptoclinidamines, are focused on. A compilation of the 13C-NMR spectral data of these selected natural indole alkaloids is also provided.  相似文献   
79.
Marine ecosystems cover more than 70% of the globe’s surface. These habitats are occupied by a great diversity of marine organisms that produce highly structural diverse metabolites as a defense mechanism. In the last decades, these metabolites have been extracted and isolated in order to test them in different bioassays and assess their potential to fight human diseases. Since traditional extraction techniques are both solvent- and time-consuming, this review emphasizes alternative extraction techniques, such as supercritical fluid extraction, pressurized solvent extraction, microwave-assisted extraction, ultrasound-assisted extraction, pulsed electric field-assisted extraction, enzyme-assisted extraction, and extraction with switchable solvents and ionic liquids, applied in the search for marine compounds. Only studies published in the 21st century are considered.  相似文献   
80.
The aim of this work was to find the most useful inorganic nitrogen source to enable Leucopaxillus giganteus to become a more nutritious mushroom, regarding organic acid and phenolic composition and total alkaloids content. For these, the influence of NH 4NO 3,NaNO 2, KNO 3,, and (NH 4) 2HPO 4 on the organic acid production was determined by HPLC-UV and total alkaloid content was assessed by a spectrophotometric method, after precipitation by Dragendorff's reagent. The results showed that L. giganteus presented an organic acid profile composed of oxalic, cis-aconitic, citric, and fumaric acids, citric acid being the major one. The quantitative organic acid profile and total alkaloid content were affected by the nitrogen source and depended on the developmental stage of mycelium and nitrogen availability. Despite being present in all samples, no phenolic compound could be identified.  相似文献   
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