全文获取类型
| 收费全文 | 298962篇 |
| 免费 | 17213篇 |
| 国内免费 | 2469篇 |
专业分类
| 林业 | 25395篇 |
| 农学 | 15599篇 |
| 基础科学 | 4192篇 |
| 47709篇 | |
| 综合类 | 37386篇 |
| 农作物 | 18262篇 |
| 水产渔业 | 18380篇 |
| 畜牧兽医 | 118560篇 |
| 园艺 | 7322篇 |
| 植物保护 | 25839篇 |
出版年
| 2021年 | 3349篇 |
| 2020年 | 3802篇 |
| 2019年 | 4541篇 |
| 2018年 | 4941篇 |
| 2017年 | 5591篇 |
| 2016年 | 5660篇 |
| 2015年 | 5297篇 |
| 2014年 | 6699篇 |
| 2013年 | 17366篇 |
| 2012年 | 8819篇 |
| 2011年 | 11120篇 |
| 2010年 | 9281篇 |
| 2009年 | 9622篇 |
| 2008年 | 10118篇 |
| 2007年 | 9113篇 |
| 2006年 | 9164篇 |
| 2005年 | 8381篇 |
| 2004年 | 7856篇 |
| 2003年 | 7528篇 |
| 2002年 | 6757篇 |
| 2001年 | 7603篇 |
| 2000年 | 7379篇 |
| 1999年 | 6580篇 |
| 1998年 | 4326篇 |
| 1997年 | 4393篇 |
| 1996年 | 4114篇 |
| 1995年 | 4734篇 |
| 1994年 | 4083篇 |
| 1993年 | 3780篇 |
| 1992年 | 5050篇 |
| 1991年 | 5213篇 |
| 1990年 | 4901篇 |
| 1989年 | 4869篇 |
| 1988年 | 4349篇 |
| 1987年 | 4387篇 |
| 1986年 | 4315篇 |
| 1985年 | 4517篇 |
| 1984年 | 4094篇 |
| 1983年 | 3771篇 |
| 1982年 | 3061篇 |
| 1981年 | 2906篇 |
| 1980年 | 2896篇 |
| 1979年 | 3620篇 |
| 1978年 | 3161篇 |
| 1977年 | 2876篇 |
| 1976年 | 2757篇 |
| 1975年 | 2680篇 |
| 1974年 | 2888篇 |
| 1973年 | 2845篇 |
| 1972年 | 2494篇 |
排序方式： 共有10000条查询结果，搜索用时 62 毫秒
991.
Russell T. Greene Gregory C. Troy 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1995,9(2):86-91
Coccidioidomycosis was diagnosed in 48 cats. Forty-one cases were identified within a period of 3 years. Coccidioides immitis was revealed by cytological or histopathological examinations, or culture in 70% of cats. The remaining 30% of cases were diagnosed by appropriate clinical signs, radiographic lesions, and serological test results. The average age of affected cats was 6.2 years with a median age of 5.0 years. Fifty-four percent (n = 26) were female and 46% (n = 22) were male. Domestic shorthaired and longhaired breeds comprised 89% (n = 41) of affected cats. Sixty-seven percent of cases were diagnosed during the 6-month period of December through May. Cats infected with C immitis were presented for evaluation of dermatologic (56%), respiratory (25%), musculoskeletal (19%), and neurological or ophthalmologic signs (19%). Fever, inappetence, and weight loss were present in 44% of the cats. Duration of clinical signs before diagnosis was less than 4 weeks in 85% (n = 42) of cats, with an average of 3.8 weeks and a median of 2 weeks. Agar gel immunodiffusion tests were positive in all 39 cats tested at sometime during the course of their disease. Hyperproteinemia (greater than 7.9 g/dL) was present in 52% (10/23) of cases. The majority of cats (n = 39) were negative for feline leukemia virus. Antibodies to feline immunodeficiency virus were absent in the 19 cats tested. Ketoconazole was the most common antifungal agent used to treat cats with Coccidioidomycosis. Duration of treatment ranged from less than 1 week to 43 months. Thirty-two cats are currently asymptomatic, with or without treatment. Eleven cats died or were euthanized. Five cats were lost to follow-up. Ketoconazole likely is more suppressive than curative because relapses were common after discontinuing therapy. 相似文献
992.
993.
Effect of age on absorption and immune responses to weaning or introduction of novel dietary antigens in pigs 总被引：14，自引：0，他引：14
Pigs weaned at three weeks old absorb food protein antigens from the intestine. The amount of antigen absorbed declines over the next three weeks, and this decline is associated with an increasing level of serum antibody to the fed proteins. There was no difference in the rate of immune elimination of intravenously injected antigen in fed and unfed controls. The reduction of serum antigen is thus likely to reflect reduced absorption, possibly mediated by locally produced antibody. Pigs weaned at 10 weeks old also absorbed antigens and produced an antibody response when introduced to soya; and after three weeks of feeding soya the absorption of antigen was substantially reduced. This latter exclusion was specific for soya as a second novel protein (ovalbumin) was absorbed when introduced to the diet at this time. At six months, pigs no longer absorbed soya proteins when they were introduced to the diet. Furthermore, pigs of this age had serum 'antibody' to soya and other proteins such as keyhole limpet haemocyanin to which they had never been exposed. 相似文献
994.
995.
C. P. Daurio E. N. Cheung A. R. Jeffcoat B. J. Skelly 《Veterinary research communications》1992,16(2):125-130
The bioavailability of three formulations of ivermectin was determined following oral administration to dogs. The average peak plasma level (C
max) of ivermectin administered in the standard tablet formulation at 6 and 100 µg/kg of body weight was 2.97 and 44.31 ng/g, respectively. This suggest dose-dependent pharmacokinetics.C
max and total ivermectin bioavailability, as assessed from the area under the plasma curve (AUC), were similar between two tablet formulations of ivermectin administered at 100 µg/kg. Furthermore,C
max was similar following administration of radiolabelled ivermectin at 6 µg/kg in either a beef-based chewable formulation or in the standard tablet formulation. 相似文献
996.
M Kachani R A Oliver C G Brown H Ouhelli R L Spooner 《Veterinary immunology and immunopathology》1992,34(3-4):221-234
Western blot analysis of Theileria annulata antigens was carried out using sera collected from cattle which had been immunised and challenged with either T. annulata sporozoites or schizont-infected cells. Three antigens between 71 and 73 kDa proved to be common to the three stages of parasite studied: sporozoites, schizonts and piroplasms. An antigen was found at 32 kDa which was specific to T. annulata piroplasms. Results were reproducible using sera from Morocco and the UK. At least one of the proteins at 71-73 kDa, but not that at 32 kDa were also recognised by sera from animals infected with Babesia species. 相似文献
997.
998.
999.
1000.