全文获取类型
收费全文 | 247156篇 |
免费 | 12923篇 |
国内免费 | 206篇 |
专业分类
林业 | 10757篇 |
农学 | 7657篇 |
基础科学 | 1663篇 |
29887篇 | |
综合类 | 44718篇 |
农作物 | 9613篇 |
水产渔业 | 11782篇 |
畜牧兽医 | 125688篇 |
园艺 | 3162篇 |
植物保护 | 15358篇 |
出版年
2018年 | 3321篇 |
2017年 | 3693篇 |
2016年 | 3431篇 |
2015年 | 2972篇 |
2014年 | 3703篇 |
2013年 | 9431篇 |
2012年 | 6745篇 |
2011年 | 8206篇 |
2010年 | 5542篇 |
2009年 | 5577篇 |
2008年 | 8127篇 |
2007年 | 7704篇 |
2006年 | 7381篇 |
2005年 | 6844篇 |
2004年 | 6776篇 |
2003年 | 6828篇 |
2002年 | 6344篇 |
2001年 | 7674篇 |
2000年 | 7528篇 |
1999年 | 5932篇 |
1998年 | 2483篇 |
1997年 | 2487篇 |
1996年 | 2327篇 |
1995年 | 2821篇 |
1994年 | 2499篇 |
1993年 | 2504篇 |
1992年 | 4999篇 |
1991年 | 5374篇 |
1990年 | 5344篇 |
1989年 | 5377篇 |
1988年 | 4873篇 |
1987年 | 4939篇 |
1986年 | 5068篇 |
1985年 | 4877篇 |
1984年 | 3941篇 |
1983年 | 3567篇 |
1982年 | 2444篇 |
1981年 | 2311篇 |
1979年 | 3576篇 |
1978年 | 2860篇 |
1977年 | 2431篇 |
1976年 | 2348篇 |
1975年 | 2487篇 |
1974年 | 3137篇 |
1973年 | 3181篇 |
1972年 | 3099篇 |
1971年 | 2920篇 |
1970年 | 2854篇 |
1969年 | 2689篇 |
1967年 | 2373篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
W. Lilenbaum J. C. Schettini G. N. Souza E. R. Ribeiro E. C. Moreira L. S. Fonseca 《Zoonoses and public health》1999,46(5):353-358
Bovine tuberculosis is a major problem in Brazil. The intradermal tuberculin test is the standard test for detection of bovine tuberculosis in Brazil but can lack both sensitivity and specificity. The purpose of this study was to compare a bovine γ-IFN assay with the tuberculin test under field conditions in Brazil. A total of 1632 animals from 13 dairy farms were tested using the single cervical tuberculin test (SCTT). Among those animals, about 15% of each herd, 220 in total, represented a high-risk group and were selected to be tested using the γ-IFN test. Of the 1632 animals tested, 207 presented significant reactions representing 12.7% of the cattle studied. In the selected group the number of animals positive by the γ-IFN assay was 126/220 (57.3%) and the total number of reactive cows on SCTT was 106/220 (48.2%). The real number of infected cattle, following standards, was 120/220 (54.5%). From these results the relative sensitivity rate of γ-IFN test was 100% including the false-positive results and 88.3% for the SCTT — a significant (P < 0.01) difference in favour of the γ-IFN test of 11.7%. The γ-IFN assay also identified some positive animals 60–120 days earlier than the SCTT. In conclusion, we believe that the γ-IFN assay can be used alone or in combination with the SCTT, as a valuable tool for the control of bovine tuberculosis in the Brazilian national herd. 相似文献
992.
993.
994.
995.
996.
Lia Koski Emilio DeBess Hilary E. Rosen Roshan Reporter Thomas Waltz Molly Leeper Jeniffer Concepcion Acevedo Renta Karpíkov Jacquelyn McCormick Tereza Gelbicova Brenda Morningstar-Shaw Megin Nichols Richard F. Leman 《Zoonoses and public health》2019,66(8):974-977
Reptile contact can result in zoonotic non‐typhoidal salmonellosis. In April 2018, Oregon Public Health Division contacted CDC about a cluster of four Salmonella serovar Fluntern (SF) illnesses in four states (OR, CA, IA, NY); patients reported contact with geckos, a popular reptile pet. PulseNet, the national molecular subtyping network of food‐borne disease surveillance, subsequently identified additional SF clinical isolates. Twelve cases in 11 states were identified; median age was 5 years (range: <1–58 years). Three patients were hospitalized; no deaths were reported. Of those with exposure information (n = 10), all reported reptile exposure; 9 (90%) specified contact with leopard geckos. No common source of geckos was identified from reported purchase locations. Los Angeles County (LAC) health officials isolated SF from one patient's leopard gecko. Five reptile/gecko isolates were identified from the USDA National Veterinary Services Laboratories (NVSL) from 2015 to 2018. Five countries responded to an Epidemic Intelligence Information System post by PulseNet; reptile isolate sequence data were received from Czech Republic. A clinical case from England was identified through the National Center for Biotechnology Information pathogen detection pipeline; the patient did not report contact with leopard geckos. Whole genome sequencing analysis revealed substantial genetic diversity between clinical and animal isolates; however, gecko and clinical isolates from LAC were highly related (1 allele difference). This investigation linking SF illnesses to leopard geckos highlights an important public health risk from pets. A better understanding of how geckos are distributed by the pet industry in the United States could improve traceability to points of origin and mitigate Salmonella transmission at gecko breeders. Earlier NVSL reports of SF isolates from geckos suggest the risk of human SF infection from geckos is not new. This investigation demonstrates a need to educate gecko breeders, retailers and gecko owners about the continued Salmonella infection risk from pet geckos. 相似文献
997.
998.
999.
1000.
B. Monteiro P. V. M. Steagall B. D. X. Lascelles S. Robertson J. C. Murrell P. W. Kronen B. Wright K. Yamashita 《The Journal of small animal practice》2019,60(8):459-462
This is the first of a series of capsule reviews published by the World Small Animal Veterinary Association ‐ Global Pain Council (WSAVA‐GPC). Each of these short articles provides a brisk assessment of the scientific evidence in specific aspects of pain management, including analgesic techniques, recommendations and controversies surrounding their use. In this first capsule review, the scientific evidence available on the long‐term use of non‐steroidal anti‐inflammatory drugs in cats with concomitant chronic pain and chronic kidney disease is discussed. 相似文献