全文获取类型
收费全文 | 1563篇 |
免费 | 97篇 |
专业分类
林业 | 59篇 |
农学 | 19篇 |
基础科学 | 17篇 |
193篇 | |
综合类 | 317篇 |
农作物 | 43篇 |
水产渔业 | 40篇 |
畜牧兽医 | 864篇 |
园艺 | 32篇 |
植物保护 | 76篇 |
出版年
2021年 | 12篇 |
2020年 | 28篇 |
2019年 | 19篇 |
2018年 | 21篇 |
2017年 | 24篇 |
2016年 | 35篇 |
2015年 | 17篇 |
2014年 | 28篇 |
2013年 | 53篇 |
2012年 | 53篇 |
2011年 | 67篇 |
2010年 | 36篇 |
2009年 | 29篇 |
2008年 | 63篇 |
2007年 | 54篇 |
2006年 | 47篇 |
2005年 | 45篇 |
2004年 | 51篇 |
2003年 | 51篇 |
2002年 | 45篇 |
2001年 | 49篇 |
2000年 | 43篇 |
1999年 | 33篇 |
1998年 | 22篇 |
1997年 | 31篇 |
1996年 | 19篇 |
1993年 | 16篇 |
1992年 | 22篇 |
1991年 | 28篇 |
1990年 | 27篇 |
1989年 | 46篇 |
1988年 | 36篇 |
1987年 | 36篇 |
1986年 | 37篇 |
1985年 | 19篇 |
1984年 | 18篇 |
1983年 | 22篇 |
1982年 | 15篇 |
1980年 | 11篇 |
1979年 | 19篇 |
1978年 | 16篇 |
1977年 | 15篇 |
1976年 | 17篇 |
1974年 | 17篇 |
1973年 | 19篇 |
1972年 | 23篇 |
1971年 | 11篇 |
1970年 | 18篇 |
1969年 | 12篇 |
1968年 | 12篇 |
排序方式: 共有1660条查询结果,搜索用时 15 毫秒
1.
R. A. S. White 《The Journal of small animal practice》1989,30(10):543-549
Sixty-two dogs with laryngeal paralysis were presented over a three year period. Presenting clinical signs included inspiratory stridor (100 per cent), exercise intolerance or syncopal episodes (81 per cent), loss or alteration in phonation (48 per cent) and coughing or gagging when eating (29 per cent). Causes of the paralysis were determined as traumatic (two dogs), neoplastic (two dogs), iatrogenic (two dogs), congenital (one dog) and idiopathic (55 dogs). Unilateral arytenoid lateralisation was performed in all dogs. The perioperative complication rate was approximately 10 per cent, while the success rate as judged by owners one year postoperatively was greater than 90 per cent. The technique avoided many of the recorded complications of intralaryngeal surgery. Operative times were short and the requirement for postoperative monitoring was minimal. Increasing familiarity with the technique favourably influenced the incidence of complications and the success rate. 相似文献
2.
3.
The structure of the shell of the egg of Trichuris trichiura was examined using light microscopy as well as scanning and transmission electron microscopy. The results confirmed its three-layered structure and provided evidence that the cores of the polar plugs, which could be seen to be extensions of the shell's middle layer, could be lost en bloc, either mechanically or chemically, and in this way probably provided an exit for the first stage larva at hatching. 相似文献
4.
5.
6.
7.
8.
Thomas R. De Ridder Justine E. Campbell Cheryl Burke‐Schwarz David Clegg Emily L. Elliot Samuel Geller Wendy Kozak Stephen T. Pittenger Jennifer B. Pruitt Jocelyn Riehl Julie White Melissa L. Wiest Chad M. Johannes John Morton Pamela D. Jones Peter F. Schmidt Victoria Gordon Paul Reddell 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2021,35(1):415-429
9.
10.
With the Journal of Veterinary Medical Education's recent summer 2005 theme issue on stress, the mental-health concerns of veterinary medical students has been brought to the forefront of the field. Since it is anticipated that research on this topic will continue and that educational institutions may implement changes based upon these results, it is of the utmost importance that this research be of the highest quality. Of particular concern with human-subject inquiries are response rates and confidentiality. In order to accommodate these concerns, an example of a survey research protocol that promotes high response rates and minimizes threats to internal validity influenced by student mistrust in assurances of confidentiality is presented. Specifically, the protocol is designed to ensure anonymity and to preserve the ability to track students longitudinally through the use of anonymous longitudinal identifiers. This protocol was tested with the first-year class of veterinary medical students at Kansas State University in October 2004 and March 2005. The two data collection periods yielded 90% and 76% response rates, respectively. The matching rate of participants, according to the anonymous longitudinal identifiers from Time 1 to Time 2, was 88%. 相似文献