全文获取类型
收费全文 | 1765篇 |
免费 | 98篇 |
国内免费 | 3篇 |
专业分类
林业 | 130篇 |
农学 | 63篇 |
基础科学 | 4篇 |
462篇 | |
综合类 | 124篇 |
农作物 | 118篇 |
水产渔业 | 94篇 |
畜牧兽医 | 706篇 |
园艺 | 49篇 |
植物保护 | 116篇 |
出版年
2024年 | 3篇 |
2023年 | 27篇 |
2022年 | 41篇 |
2021年 | 80篇 |
2020年 | 83篇 |
2019年 | 95篇 |
2018年 | 75篇 |
2017年 | 63篇 |
2016年 | 72篇 |
2015年 | 58篇 |
2014年 | 64篇 |
2013年 | 117篇 |
2012年 | 139篇 |
2011年 | 149篇 |
2010年 | 84篇 |
2009年 | 53篇 |
2008年 | 114篇 |
2007年 | 104篇 |
2006年 | 93篇 |
2005年 | 77篇 |
2004年 | 61篇 |
2003年 | 48篇 |
2002年 | 41篇 |
2001年 | 14篇 |
2000年 | 8篇 |
1999年 | 11篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1977年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1958年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1866条查询结果,搜索用时 31 毫秒
1.
Karen R. Muñana Patricia J. Luttgen Mary Anna Thrall Thomas W. Mitchell David A. Wenger 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1994,8(2):117-121
Seven Domestic shorthair cats with a lysosomal storage disorder analogous to human Niemann-Pick disease type C, from a breeding colony were studied to characterize the neurological manifestations of this disorder. Affected cats were identified by means of liver biopsies at 4 to 6 weeks of age. Neurological examinations were performed at 2 week intervals from the onset of clinical signs. All cats displayed signs referrable to the cerebellum, with a subtle intention tremor noticed initially at 8 to 12 weeks of age; the disease was rapidly progressive. The tremor became more pronounced, menace response was lost, and severe dysmetria and ataxia developed. Three cats also had signs referrable to other areas of the central nervous system. Cats died or were euthanized between 12 and 43 weeks of age. Pathological findings included accumulation of substrate within neurons throughout the central nervous system, and axonal spheroid formation. The clinical and pathological findings in these cats are comparable to those in the human form of the disease. 相似文献
2.
Christian Walzer Anna Kübber-Heiss Nadia Robert 《Journal of veterinary diagnostic investigation》2002,14(1):76-79
Removal of the spinal cord is considered time consuming and difficult. A delay in the necropsy procedure, especially in the central nervous system, can result in significant tissue autolysis and subsequent diagnostic difficulties. In the field, where many necropsies are performed, suitable electric saws are mostly unavailable. A technically simple and rapid method for spinal cord removal, requiring only a straightforward tool, has been devised. No necropsy-induced structural damage has been noted on histopathologic examination. 相似文献
3.
4.
Movements of bank voles (Clethrionomys glareolus) were studied in a farmland mosaic in Poland. Distances crossed by animals in short-time periods are significantly longer in heterogenous than in homogenous habitats. In long-time and large-spatial scales, a significant portion of the animals in a population travel among habitat elements of the mosaic, reducing the degree of isolation of patch populations and decreasing the probability of local extinction. 相似文献
5.
Anna R M Gelzer Marc S Kraus 《Veterinary Clinics of North America: Small Animal Practice》2004,34(5):1127-44, vi
Atrial fibrillation (AF) is the most common clinically important arrhythmia in veterinary medicine. Electrical cardioversion of AF to sinus rhythm is feasible, but pharmacologic rate control is an effective and achievable treatment strategy for most veterinary patients. Recent human trials suggest that rate control and rhythm control are almost equally beneficial. Nevertheless, AF can be a challenging arrhythmia to manage, because most affected animal shave numerous other concurring problems associated with the underlying heart disease that dictate or influence the clinician's choice of treatment and monitoring strategy for each patient. 相似文献
6.
7.
8.
9.
The effect of temperature and light intensity on the polar lipidome of endophytic brown algae Streblonema corymbiferum and Streblonema sp. in vitro was investigated. More than 460 molecular species have been identified in four glycoglycerolipids classes, five phosphoglycerolipids classes and one betaine lipid class. The lipids glucuronosyldiacylglycerol and diacylglyceryl-N,N,N-trimethyl-homoserine were found in the algae of the order Ectocarpales for the first time. A decrease in cultivation temperature led to an increase in the unsaturation level in all classes of polar lipids. Thus, at low temperatures, the content of 18:4/18:4 monogalactosyldiacylglycerol (MGDG), 20:5/18:4 digalactosyldiacylglycerol (DGDG), 18:3/16:0 sulfoquinovosyldiacylglycerol (SQDG), 18:3/18:3 and 18:3/18:4 phosphatidylglycerol (PG), 20:4/20:5 and 20:5/20:5 phosphatidylethanolamine (PE), 14:0/20:5, 16:0/20:5 and 20:5/20:5 phosphatidylcholine (PC), 20:5/20:4 phosphatidylhydroxyethylglycine and 18:1/18:2 DGTS increased. At high temperatures, an increase in the content of chloroplast-derived MGDG, DGDG and PG was observed. Both low and high light intensities caused an increase in 20:5/18:3 MGDG and 18:3/16:1 PG. At low light intensity, the content of DGDG with fatty acid (FA) 18:3 increased, and at high light intensity, it was with FA 20:5. The molecular species composition of extraplastid lipids also showed a dependence on light intensity. Thus, the content of PC and PE species with C20-polyunsaturated FA at both sn-positions, 18:1/18:1 DGTS and 16:0/18:1 phosphatidylinositol increased. Low light intensity induced a significant increase in the content of chloroplast-derived 18:1/16:1 phosphatidylethanolamine. 相似文献
10.
Natoli E Maragliano L Cariola G Faini A Bonanni R Cafazzo S Fantini C 《Preventive veterinary medicine》2006,77(3-4):180-185
In Italy, which is rabies-free, the national Law No. 281 [Legge Nazionale 14 agosto 1991. No. 281: Legge Quadro in materia di animali di affezione e prevenzione del randagismo. Gazz. Uff. Rep. Ital. no 203 del 30 agosto 1991: p. 3] on the management of pets and on the control of feral cats has introduced the no-kill policy for this species. Thus, “trap-neuter-release” (TNR) programs have been carried out for >10 years. In this paper we present data on registered colonies and censused cats in Rome from 1991 to 2000; the results of the neutering campaign from 1991 to 2000; and a survey, on 103 cat colonies, on the effects of demographic control of urban feral-cat colonies in the city of Rome, carried out by the local Veterinary Public Services (VPS) in collaboration with the associations of cat care-takers. In 10 years almost 8000 were neutered and reintroduced in their original colony. The spay/neuter campaigns brought about a general decrease in cat number but the percentage of cat immigration (due to abandonment and spontaneous arrival) is around 21%. This suggests that all these efforts without an effective education of people to control the reproduction of house cats (as a prevention for abandonment) are a waste of money, time and energy. 相似文献