全文获取类型
收费全文 | 101485篇 |
免费 | 5350篇 |
国内免费 | 774篇 |
专业分类
林业 | 6920篇 |
农学 | 3839篇 |
基础科学 | 821篇 |
13504篇 | |
综合类 | 17195篇 |
农作物 | 5246篇 |
水产渔业 | 5908篇 |
畜牧兽医 | 44998篇 |
园艺 | 2180篇 |
植物保护 | 6998篇 |
出版年
2021年 | 831篇 |
2020年 | 920篇 |
2019年 | 1068篇 |
2018年 | 4055篇 |
2017年 | 4246篇 |
2016年 | 2683篇 |
2015年 | 1540篇 |
2014年 | 1700篇 |
2013年 | 3224篇 |
2012年 | 3940篇 |
2011年 | 5798篇 |
2010年 | 4417篇 |
2009年 | 3472篇 |
2008年 | 4583篇 |
2007年 | 4668篇 |
2006年 | 2877篇 |
2005年 | 2839篇 |
2004年 | 2575篇 |
2003年 | 2656篇 |
2002年 | 2377篇 |
2001年 | 2565篇 |
2000年 | 2641篇 |
1999年 | 1996篇 |
1998年 | 812篇 |
1997年 | 722篇 |
1995年 | 749篇 |
1993年 | 683篇 |
1992年 | 1547篇 |
1991年 | 1735篇 |
1990年 | 1657篇 |
1989年 | 1617篇 |
1988年 | 1486篇 |
1987年 | 1545篇 |
1986年 | 1584篇 |
1985年 | 1409篇 |
1984年 | 1196篇 |
1983年 | 1018篇 |
1982年 | 682篇 |
1979年 | 1061篇 |
1978年 | 831篇 |
1977年 | 684篇 |
1976年 | 719篇 |
1975年 | 750篇 |
1974年 | 1007篇 |
1973年 | 988篇 |
1972年 | 956篇 |
1971年 | 884篇 |
1970年 | 853篇 |
1969年 | 809篇 |
1967年 | 710篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
L.E. Young D.H. Bartram M. Diamond A. Gregg R.S. Jones 《Veterinary anaesthesia and analgesia》1991,18(Z1):171-174
52.
L A Janssens 《Veterinary surgery : VS》1991,20(4):274-278
Seven foci of pain (trigger points) were identified in the triceps brachii, infraspinatus, adductor-pectineus, peroneus longus, gluteus medius, ileocostorum lumborum, and quadriceps femoris muscles in 48 lame dogs. The dogs had been lame for 1 day to 150 weeks (mean, 24 weeks). Thirty-one dogs had been treated unsuccessfully with corticosteroids, nonsteroidal anti-inflammatory drugs, analgesics, or acupuncture. Palpating the trigger points induced severe pain. Treatment consisted of weekly stimulation of the trigger points by needling or injection of a local anesthetic. The mean treatment period was 2.8 weeks. Excellent results and complete recovery were observed in 34 dogs (60%). 相似文献
53.
R. Iori O. Leoni L. Lazzeri G. Mosca S. Palmieri 《Journal of Agronomy and Crop Science》1991,167(2):91-95
Samples of rapeseed from three Italian growing environments (Bologna, Perugia and Palermo) were analysed for glucose content and dry weight of 1000 seeds every three or four days starting from the end of flowering until complete ripening. In addition, the content of oil, soluble and total proteins, glucosinolates and myrosinase activity was determined in samples of mature seeds. The cultivars used were jet Neuf and Lingot (type 0) and Tandem, Jade and Santana (type 00). From the results it emerged that the point of intersection of the two branches of the linear regression plots for different glucose-consumption kinetics found during seed filling, in addition to being strongly affected by the climate of the test environment, is correlated with quantitative and qualitative production, independently of the genotype. 相似文献
54.
J Sherrill T Schock J L Dunn D J St Aubin V V Burnley S E Poet 《Journal of zoo and wildlife medicine》2001,32(1):17-24
Humoral immune responses of black-footed penguins (Spheniscus demersus) to DNA-mediated immunization with a beta-galactosidase reporter gene expression plasmid were evaluated. Six male and 6 female adult penguins received either test plasmid, pCMV-beta, containing the beta-galactosidase gene or control plasmid, pCI, lacking a gene for expression. Three birds from each group were used previously in a diluent control group and given one injection of sterile saline. All samples were screened for anti-beta-galactosidase antibodies by indirect enzyme-linked immunosorbent assay with anti-chicken immunoglobulin G as secondary antibody. Antibodies to beta-galactosidase were detected in the sera of pCMV-beta-inoculated penguins, with a peak response on day 21. Antibody titers of the test plasmid group versus both control groups on days 21, 28, and 42 differed significantly. These results demonstrate that black-footed penguins can be safely transfected with the gene encoding beta-galactosidase and will mount a humoral response against the in vivo-expressed protein. Knowledge from this initial study can be applied to the development of DNA-mediated vaccines against specific infectious diseases of penguins. 相似文献
55.
56.
Jennifer L Davis 《Veterinary Clinics of North America: Equine Practice》2003,19(3):765-778
In summary, peritonitis in the horse is a potentially life-threatening disease that must be treated promptly and aggressively. Therapy should be aimed at reducing systemic shock and hypovolemia, correction of the primary cause, antibiotic and anti-inflammatory therapy, and abdominal drainage and lavage. The prognosis depends on the ability to diagnose and treat the underlying cause and prevent the development of complications. Mortality rates can be as high as 59.7%, with horses developing postoperative peritonitis having a 56% mortality rate. Long-term complications like adhesion formation or internal abscesses may further reduce the survival rate. The prognosis is best determined by an early and quick response to aggressive treatment. 相似文献
57.
Blomquist HL 《Science (New York, N.Y.)》1938,88(2272):59-60
58.
Eidinoff ML 《Science (New York, N.Y.)》1948,108(2811):535-536
59.
60.
L C Savon M Alonso J Rodriguez-Diego T Blandino 《Revue d'élevage et de médecine vétérinaire des pays tropicaux》1992,45(1):30-31
The attenuation of a Babesia bovis strain depends on its protease content. The present work evaluates this parameter on a virulent strain, before and after attenuation by quick passages on splenectomized calves. The protease activity at different pH values was determined in protein fractions from the blood of calves. The enzymatic test showed marked differences between the protease content of both substrains. 相似文献