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291.
Marine tropical carnivorous (MTC) fish are less tolerant to high dietary lipid compared with cold and temperate climate fish. However, insufficient n‐3 long‐chain (≥C20) polyunsaturated fatty acids (LC‐PUFA) compromises MTC fish health and growth which requires attention when choosing lipid sources in aquafeed formulations. Fish oil (FO) has been the major lipid source for feeding key MTC fish. We estimated that more than 200 thousand tonnes of FO were used to feed farmed MTC fish in 2016, representing nearly 25% of global FO production. Nevertheless, recent increases in FO prices and demand, and the foreseen inability of wild fisheries to produce sufficient FO in the future, have created a need for cheaper and more sustainable alternatives. Meta‐analysis showed that feeding vegetable oils (VO) to MTC fish can slightly reduce their growth, with a marked decrease in n‐3 LC‐PUFA content in the fish tissues corresponding with the increased replacement of FO and fishmeal in the diet. Rendered terrestrial animal fat or modulating the bioconversion of n‐3 LC‐PUFA precursors in VO can be utilised further in MTC fish nutrition with more research recommended on these approaches. Oils and oil‐rich meals from non‐food marine organisms are rich in n‐3 LC‐PUFA and represent an underutilised alternative to FO for tropical aquaculture. With oils rich in n‐3 LC‐PUFA produced from transgenic plants presently gaining regulatory approvals and becoming available as a renewable alternative to FO, aquaculture in the tropics and around the globe is ready to leap into a new phase of sustainable expansion. 相似文献
292.
Formal training in conservation biology education is an important component of the suite of solutions to current environmental problems. As conservation biology textbooks underpin many conservation education programs at both undergraduate and graduate levels, the portrayal of conservation issues and coverage of specific biotic groups plays a potentially important role in guiding the training of the next generation of conservation professionals. Parasites represent the majority of species diversity on earth, play critical roles in ecology and evolution, and are often at higher risk of decline and extinction than their free-living counterparts. Yet parasites continue to receive scant attention from conservation scientists and educators. We searched the index of 77 English language conservation biology textbooks for parasite or pathogen related content, published between 1970 and 2009. When present, we categorized a textbook’s parasite content as positive, neutral or negative with respect to the author’s portrayal of parasite biodiversity. The vast majority (72%) of conservation textbooks either portray parasites uniquely as threats to conservation goals established for free-living species or do not mention parasites at all. While no single textbook can be expected to provide extensive treatment of conservation-related topics across all biological groups, we outline three reasons why parasites should feature more prominently in formal conservation education, and suggest several ways in which greater incorporation of these parasite topics could strengthen the teaching and practice of conservation biology. 相似文献
293.
Absorption kinetics of regular, isophane (NPH), and protamine zinc (PZI) insulin were evaluated in seven clinically normal domestic shorthair cats by measurement of serial serum concentrations of insulin after subcutaneous administration of each insulin preparation. These results were compared to measurements of serial serum insulin concentrations after similar dosages of regular insulin were administered intravenously. Regular insulin administered subcutaneously was better absorbed than NPH and PZI insulins (mean bioavailability index 45.4% vs. 33.0% for NPH and 27.3% for PZI), and resulted in a significantly greater maximal increase in mean circulating insulin concentrations above baseline values (3529 pM vs. 1044 pM for NPH and 344 pM for PZI, P<0.05). The mean time interval between insulin administration and time to reach peak concentrations was significantly shorter for regular insulin than for NPH or PZI insulin (0.5 hr vs. 1.6 hr for NPH and 4.1 hr for PZI, P<0.05). There was also a significant difference (P<0.05) in the mean time interval between insulin injection and return of serum insulin concentrations to baseline values between regular insulin (5.6 hr) and NPH (7.7 hr) or PZI (13.1 hr) insulins. When compared with PZI, NPH insulin showed a significantly (P<0.05) greater maximal increase in mean serum insulin concentrations over baseline values. In addition, the interval between insulin administration and time to reach peak concentrations, as well as the time between insulin injection and return of serum insulin concentrations to baseline values, were also significantly shorter with NPH insulin than with PZI. These results suggest that NPH and PZI insulins administered subcutaneously to cats may require a short time to reach peak serum insulin concentrations as well as a relatively short time for circulating insulin concentrations to return to baseline values. If the absorption kinetics are similar to that in this study, most cats with diabetes mellitus would need twice daily injection of NPH or PZI insulin to adequately control the diabetic state. 相似文献
294.
J. Nichols S. KangW. Post D. WangV. Bandaru D. ManowitzX. Zhang R. Izaurralde 《Computers and Electronics in Agriculture》2011,79(2):112-115
Multiple concerns over the impact of wide scale changes in land management have motivated comprehensive analyses of environmental sustainability of food and biofuel production. These call for high-resolution land management tools that enable comprehensive analyses of natural resources for decision-making. The agroecosystem simulation models with the most biophysical detail are point models, which often have a user interface that allows users to provide inputs and examine results for agricultural field scale analyses. These are not able to meet the needs of high-resolution regional or national simulations. We describe an efficient computational approach for deployment of the Environmental Policy Integrated Climate (EPIC) model at high-resolution spatial scales using high performance computing (HPC) techniques. We developed an integrated procedure for executing the millions of simulations required for high-resolution, regional studies, and also address building databases for model initialization, model forcing data, and model outputs. We first ported EPIC from Windows to an HPC platform and validated output from both platforms. We then developed methods of packaging simulations for efficient, unattended parallel execution on the HPC cluster. The job queuing system, Portable Batch System (PBS) is employed to control job submission. Simulation outputs are extracted to PostgreSQL database for analysis. In a case study covering four counties in central Wisconsin using HPC-EPIC, we finished over 140 K simulations in a total of 10 h on an HPC cluster using 20 nodes. This is a speedup of 40 times. More nodes could be used to achieve larger speedups. The HPC-EPIC model developed in this study is anticipated to provide information useful for high-resolution land use management and decision making. The framework for high-performance computing can be extended to other traditional, point-based biophysical simulation models. 相似文献
295.
Embryonic and Early Foetal Losses in Cattle and Other Ruminants 总被引:1,自引:0,他引:1
296.
Field peas (Pisum sativum) were evaluated as a potential feedstock for ethanol production. Ground peas were dry‐milled and separated into starch, protein, and fibrous fractions by air classification. Starch‐enriched fractions prepared from whole peas and dehulled peas contained 73.7% wt and 77.8% wt starch, respectively, a nearly two‐fold enrichment compared with whole peas. The fractions were liquefied and saccharified using industrial α‐amylase and glucoamylase at recommended enzyme loadings. A final ethanol concentration of 11.0% (w/v) was obtained in 48–52 hr, with yields of 0.43–0.48 g of ethanol/g of glucose. Starch present in whole ground peas was also saccharified and fermented, with 97% of the starch fermented when an autoclaving step was included in the liquefaction stage. 相似文献
297.
298.
299.
Container mixes consisting of Pinus radiata bark and brown coal or clay loam soil have poor wetting properties when they are dry, because of the shrinkage of all three and the hydrophobic nature of dry pinebark. The wettability of coarse sand, which is independent of its dryness, is quantitatively transferred to container mixes in proportion to the amount used. 相似文献
300.