全文获取类型
收费全文 | 221篇 |
免费 | 5篇 |
专业分类
林业 | 35篇 |
农学 | 15篇 |
基础科学 | 1篇 |
37篇 | |
综合类 | 31篇 |
农作物 | 5篇 |
水产渔业 | 6篇 |
畜牧兽医 | 78篇 |
园艺 | 2篇 |
植物保护 | 16篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 11篇 |
2013年 | 4篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2008年 | 8篇 |
2007年 | 11篇 |
2006年 | 13篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 7篇 |
2001年 | 7篇 |
1999年 | 3篇 |
1997年 | 2篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 3篇 |
1979年 | 3篇 |
1976年 | 2篇 |
1975年 | 10篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 4篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1965年 | 2篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1955年 | 1篇 |
1943年 | 1篇 |
1941年 | 1篇 |
1911年 | 4篇 |
1867年 | 1篇 |
1864年 | 1篇 |
1862年 | 1篇 |
排序方式: 共有226条查询结果,搜索用时 312 毫秒
91.
92.
93.
94.
A commercially available (cELISA) kit for diagnosing Anaplasma marginale infection in cattle was validated for diagnosing A ovis infection in sheep using the bovine serum controls as supplied by the manufacturer (BcELISA) and sheep serum controls from pathogen-free sheep (OcELISA). True positives were identified using two previously established assays, a nested PCR (nPCR) test and an indirect immunofluorescent assay (IFA). The BcELISA was also applied to sera from various species of wild ruminants, comparing the results with the IFA. Receiver operating characteristic (ROC) analysis indicated that the predicted threshold inhibition for the BcELISA was 19.2. The sensitivity for the BcELISA was 98.2% and the specificity was 96.3%. The predicted threshold inhibition decreased to 14.3 for the OcELISA; the sensitivity was 96.5% and the specificity was 98.1%. There was >/=90% concordance between IFA and nPCR, as well as between the BcELISA at 19% inhibition cutoff and either IFA or PCR. Concordance between the cELISA and IFA using sera from elk, mule deer, bighorn sheep, pronghorn antelope, and black-tailed deer ranged from 64% to 100%. This commercially available cELISA test kit can be used very effectively to test domestic sheep for infection with A. ovis using the kit-supplied controls (i.e. the BcELISA) and a 19% inhibition cutoff; the kit may also be useful for detecting intra-erythrocytic Anaplasma infections in wild ruminants. 相似文献
95.
Handl S Hellweg P Khol-Parisini A Rossmann B Thurner K Luf W Novak J Zentek J 《Journal of animal physiology and animal nutrition》2008,92(3):242-245
Oregano possesses high antioxidant activity and could therefore be used to enhance oxidative stability of eggs high in omega3 fatty acids. In this study, 20 female quails were fed a diet containing 4% linseed oil. They were divided into two groups, one receiving oregano, and the other grass meal as control (2% respectively). Cholesterol oxidation products were analysed in fresh eggs, in stored eggs and in the livers. Trolox equivalent antioxidative capacity of plasma was measured. No significant differences were seen between the groups. 相似文献
96.
Sandra Rodriguez-Pi?eros Will Focht David K. Lewis Diane Montgomery 《Small-Scale Forestry》2012,11(2):167-183
Incorporating people’s values into forest management plans is an important component of sustainable forestry practice. Q methodology
was used to identify perspectives on sustainable management of a community-owned forest reserve in a village in Puebla, Mexico.
The study demonstrates the value of Q methodology in characterizing the views of citizens toward the forest and accommodating
these views in a sustainable forest management plan. The plan we developed based on our research enjoyed widespread community
support and far outdistanced its support of two alternative plans developed by outsiders. Our plan reflected the village’s
strong preference for non-consumptive uses with regulated timber harvesting to sustain the ecological health of the forest
and to provide short-term economic benefits. 相似文献
97.
Designing relevant biochars as soil amendments using lignocellulosic-based and manure-based feedstocks 总被引:1,自引:0,他引:1
Jeffrey M. Novak Keri B. Cantrell Donald W. Watts Warren J. Busscher Mark G. Johnson 《Journal of Soils and Sediments》2014,14(2):330-343
Purpose
Biochars are a by-product of the biofuel processing of lignocellulosic and manure feedstocks. Because biochars contain an assemblage of organic and inorganic compounds, they can be used as an amendment for C sequestration and soil quality improvement. However, not all biochars are viable soil amendments; this is because their physical and chemical properties vary due to feedstock elemental composition, biofuel processing, and particle size differences. Biochar could deliver a more effective service as a soil amendment if its chemistry was designed ex ante with characteristics that target specific soil quality issues. In this study, we demonstrate how biochars can be designed with relevant properties as successful soil amendments through feedstock selection, pyrolysis conditions, and particle size choices.Materials and methods
Biochars were produced by pyrolysis of parent lignocellulosic feedstock sources—peanut hull (PH; Archis hypogaea), pecan shell (PS; Carya illinoensis), switchgrass (SG; Panicum virgatum), pine chips (PC; Pinus taeda), hardwood wastes (wood), and poultry litter manure (PL; Gallus domesticus), as well as blends of these feedstocks at temperatures ranging from 250 to 700 °C. Additionally, blended feedstocks were made into pellets (>2 mm) prior to pyrolysis at 350 °C. Dust-sized (<0.42 mm) biochar was obtained through grinding of pelletized biochars. After chemical characterization, the biochars were evaluated as fertility amendments in a Norfolk soil (fine-loamy, kaolinitic, thermic, Typic Kandiudult) during two different pot incubation experiments.Results and discussion
PL biochars were alkaline and enriched in N and P, whereas biochar from lignocellulosic feedstocks exhibited mixed pH and nutrient contents. Blending PL with PC resulted in lower biochar pH values and nutrient contents. In pot experiment 1, most biochars significantly (P?<?0.05) raised soil pH, soil organic carbon, cation exchange capacity, and Mehlich 1 extractable P and K. PL biochar added at 20 g?kg?1 resulted in excessive soil P concentrations (393 to 714 mg?kg?1) and leachate enriched with dissolved phosphorus (DP, 22 to 70 mg?L?1). In pot experiment 2, blended and pelletized PL with PC feedstock reduced soil pH and extractable soil P and K concentrations compared to pot experiment 1. Water leachate DP concentrations were significantly (P?<?0.05) reduced by pelletized biochar blends.Conclusions
Short-term laboratory pot experiments revealed that biochars can have different impacts at modifying soil quality characteristics. Keying on these results allowed for creating designer biochars to address specific soil quality limitations. In the process of manufacturing designer biochars, first, it is important to know what soil quality characteristics are in need of change. Second, choices between feedstocks, blends of these feedstocks, and their accompanying particle sizes can be made prior to pyrolysis to create biochars tailored for addressing specific soil quality improvements. Utilization of these principles should allow for effective service of the designed biochar as a soil amendment while minimizing unwanted ex facto soil quality changes and environmental effects. 相似文献98.
Boonchit S Alhassan A Chan B Xuan X Yokoyama N Ooshiro M Goff WL Waghela SD Wagner G Igarashi I 《Veterinary parasitology》2006,137(1-2):28-35
Recombinant antigen-based enzyme-linked immunosorbent assay (ELISA) was developed for the serological diagnosis of Babesia bigemina infection by using a full-length B. bigemina rhoptry-associated protein 1 (rRAP-1) and the truncated C-terminal RAP-1 (rRAP-1/CT). While the rRAP-1 showed cross reactivity between B. bigemina- and Babesia bovis-infected bovine sera, the rRAP-1/CT was highly specific to B. bigemina-infected bovine sera and proved useful in the detection of sequential sera collected from an experimentally infected cow during the acute and latent infection. The high yield of soluble rRAP-1/CT and its diagnostic specificity demonstrate its potential in the diagnosis of B. bigemina infection. Its usefulness for epidemiological investigation is currently being evaluated. 相似文献
99.
Babesia bovis causes an acute and often fatal infection in adult cattle, which if resolved, leads to a state of persistent infection in otherwise clinically healthy cattle. Persistently infected cattle are generally resistant to reinfection with related parasite strains, and this resistance in the face of infection is termed concomitant immunity. Young animals are generally more resistant than adults to B. bovis infection, which is dependent on the spleen. Despite the discovery of B. bovis over a century ago, there are still no safe and effective vaccines that protect cattle against this most virulent of babesial pathogens. Immunodominant antigens identified by serological reactivity and dominant T-cell antigens have failed to protect cattle against challenge. This review describes the innate and acquired immune mechanisms that define resistance in young calves and correlate with the development of concomitant immunity in older cattle following recovery from clinical disease. The first sections will discuss the innate immune responses by peripheral blood- and spleen-derived macrophages in cattle induced by B. bovis merozoites and their products that limit parasite replication, and comparison of natural killer cell responses in the spleens of young (resistant) and adult (susceptible) cattle. Later sections will describe a proteomic approach to discover novel antigens, especially those recognized by immune CD4+ T lymphocytes. Because immunodominant antigens have failed to stimulate protective immunity, identification of subdominant antigens may prove to be important for effective vaccines. Identification of CD4+ T-cell immunogenic proteins and their epitopes, together with the MHC class II restricting elements, now makes possible the development of MHC class II tetramers and application of this technology to both quantify antigen-specific lymphocytes during infection and discover novel antigenic epitopes. Finally, with the imminent completion of the B. bovis genome-sequencing project, strategies using combined genomic and proteomic approaches to identify novel vaccine candidates will be reviewed. The availability of an annotated B. bovis genome will, for the first time, enable identification of non-immunodominant proteins that may stimulate protective immunity. 相似文献
100.
Willem M Garratt AN Novak B Citron M Kaufmann S Rittger A DeStrooper B Saftig P Birchmeier C Haass C 《Science (New York, N.Y.)》2006,314(5799):664-666
Although BACE1 (beta-site amyloid precursor protein-cleaving enzyme 1) is essential for the generation of amyloid-b peptide in Alzheimer's disease, its physiological function is unclear. We found that very high levels of BACE1 were expressed at time points when peripheral nerves become myelinated. Deficiency of BACE1 resulted in the accumulation of unprocessed neuregulin 1 (NRG1), an axonally expressed factor required for glial cell development and myelination. BACE1-/- mice displayed hypomyelination of peripheral nerves and aberrant axonal segregation of small-diameter afferent fibers, very similar to that seen in mice with mutations in type III NRG1 or Schwann cell-specific ErbB2 knockouts. Thus, BACE1 is required for myelination and correct bundling of axons by Schwann cells, probably through processing of type III NRG1. 相似文献