全文获取类型
收费全文 | 299篇 |
免费 | 27篇 |
专业分类
林业 | 4篇 |
农学 | 2篇 |
48篇 | |
综合类 | 64篇 |
农作物 | 8篇 |
畜牧兽医 | 192篇 |
园艺 | 2篇 |
植物保护 | 6篇 |
出版年
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 10篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 25篇 |
2012年 | 9篇 |
2011年 | 9篇 |
2010年 | 13篇 |
2009年 | 10篇 |
2008年 | 10篇 |
2007年 | 13篇 |
2006年 | 15篇 |
2005年 | 12篇 |
2004年 | 12篇 |
2003年 | 11篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 14篇 |
1997年 | 11篇 |
1996年 | 9篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1966年 | 2篇 |
1945年 | 3篇 |
1941年 | 2篇 |
1929年 | 2篇 |
1920年 | 1篇 |
1917年 | 2篇 |
1915年 | 1篇 |
1913年 | 1篇 |
1912年 | 2篇 |
1911年 | 3篇 |
1906年 | 1篇 |
排序方式: 共有326条查询结果,搜索用时 15 毫秒
101.
102.
A computer program was devised to extract information about the fertility of bulls from a bovine reproduction data bank used in a dairy herd health program. The data necessary for the analysis was already stored in the data bank so that the cost of performing the calculation arose from the writing of the program, and the subsequent computer time required to run it. 相似文献
103.
Giancarlo Pizza Paul H Levine Dharam V Ablashi Gary Armstrong Zakir Bengali Grace B Cannon 《Comparative immunology, microbiology and infectious diseases》1982,5(4):437-446
Humoral and cell-mediated immunity (CMI) to herpesvirus saimiri (HVS), an oncogenic lymphotropic herpesvirus, was studied in squirrel and rhesus monkeys. Natural antibody to HVS was found in five of six squirrel monkeys but there was no evidence of specific CMI directed against HVS. Rhesus monkeys did not show natural antibody or CMI against HVS antigens. Immunization with HVS, however, produced both antibody and specific CMI in the rhesus monkeys, but no CMI developed in the squirrel monkeys. These findings are important in the development of animal models for the treatment of tumors associated with lymphotropic herpesviruses. 相似文献
104.
C. M. Cannon M. C. Scott D. Ito B. H. Gorden A. J. Graef J. F. Modiano 《Veterinary and comparative oncology》2015,13(1):48-59
We evaluated the effect of Aurora kinase inhibitors AZD1152 and VX680 on canine osteosarcoma cells. Cytotoxicity was seen in all four cell lines; however, half‐maximal inhibitory concentrations were significantly higher than in human leukaemia and canine lymphoma cells. AZD1152 reduced Aurora kinase B phosphorylation, indicating resistance was not because of failure of target recognition. Efflux mediated by ABCB1 and ABCG2 transporters is one known mechanism of resistance against these drugs and verapamil enhanced AZD1152‐induced apoptosis; however, these transporters were only expressed by a small percentage of cells in each line and the effects of verapamil were modest, suggesting other mechanisms contribute to resistance. Our results indicate that canine osteosarcoma cells are resistant to Aurora kinase inhibitors and suggest that these compounds are unlikely to be useful as single agents for this disease. Further investigation of these resistance mechanisms and the potential utility of Aurora kinase inhibitors in multi‐agent protocols is warranted. 相似文献
105.
Foot-and-mouth disease virus (FMDV) infected animals can contaminate the environment with their secretions and excretions. To quantify the contribution of a contaminated environment to the transmission of FMDV, this study used calves that were not vaccinated and calves that were vaccinated 1 week prior to inoculation with the virus in direct and indirect contact experiments. In direct contact experiments, contact calves were exposed to inoculated calves in the same room. In indirect contact experiments, contact calves were housed in rooms that previously had held inoculated calves for three days (either from 0 to 3 or from 3 to 6 days post inoculation). Secretions and excretions from all calves were tested for the presence of FMDV by virus isolation; the results were used to quantify FMDV transmission. This was done using a generalized linear model based on a 2 route (2R, i.e. direct contact and environment) SIR model that included information on FMDV survival in the environment. The study shows that roughly 44% of transmission occurs via the environment, as indicated by the reproduction ratio that equalled 2.0, whereas the sum of and equalled 4.6. Because vaccination 1 week prior to inoculation of the calves conferred protective immunity against FMDV infection, no transmission rate parameters could be estimated from the experiments with vaccinated calves. We conclude that a contaminated environment contributes considerably to the transmission of FMDV therefore that hygiene measures can play a crucial role in FMD control.
Electronic supplementary material
The online version of this article (doi:10.1186/s13567-015-0156-5) contains supplementary material, which is available to authorized users. 相似文献106.
Cannon WB 《Science (New York, N.Y.)》1933,78(2012):43-48
107.
108.
109.
110.
Spring wheat (Triticum aestivum L.) dry matter (DM), N content and tillering are increased by increasing the proportion of N available to the plant as NH4 (enhanced ammonium supply‐EAS) at soil pH ≥ 7.0. Using different N sources to provide different levels of EAS effects soil pH and electrical conductivity (EC) as well as soil NH4. Both pH and EC may affect plant growth and response to EAS. Two greenhouse experiments were conducted to determine the effects of EAS, pH, and EC on the DM, N content, and tillering of spring wheat. The collinearity between pH and NH4 was eliminated over a pH range of 5.8 to 7.2 by adjusting lime rates to compensate for the effect of each N source on pH. Even though EC was somewhat correlated with soil NH4 in both experiments, there were a sufficient number of comparisons to separate the effects of EC and NH4 on plant growth. Differences in plant growth resulted from differences in soil NH4 levels. Soil pH and EC did not affect plant growth. Plant responses to soil NH4 levels were quadratic. Maximum plant growth occurred at approximately 100–200 mg/kg KCl‐extractable NH4. 相似文献