全文获取类型
收费全文 | 1777篇 |
免费 | 146篇 |
国内免费 | 4篇 |
专业分类
林业 | 95篇 |
农学 | 41篇 |
基础科学 | 7篇 |
200篇 | |
综合类 | 265篇 |
农作物 | 51篇 |
水产渔业 | 159篇 |
畜牧兽医 | 955篇 |
园艺 | 46篇 |
植物保护 | 108篇 |
出版年
2023年 | 16篇 |
2022年 | 15篇 |
2021年 | 32篇 |
2020年 | 61篇 |
2019年 | 52篇 |
2018年 | 54篇 |
2017年 | 48篇 |
2016年 | 58篇 |
2015年 | 39篇 |
2014年 | 52篇 |
2013年 | 85篇 |
2012年 | 108篇 |
2011年 | 139篇 |
2010年 | 80篇 |
2009年 | 67篇 |
2008年 | 100篇 |
2007年 | 91篇 |
2006年 | 91篇 |
2005年 | 86篇 |
2004年 | 81篇 |
2003年 | 67篇 |
2002年 | 73篇 |
2001年 | 23篇 |
2000年 | 27篇 |
1999年 | 34篇 |
1998年 | 23篇 |
1997年 | 22篇 |
1996年 | 23篇 |
1995年 | 12篇 |
1994年 | 8篇 |
1993年 | 16篇 |
1992年 | 7篇 |
1991年 | 12篇 |
1990年 | 14篇 |
1989年 | 22篇 |
1988年 | 15篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 12篇 |
1984年 | 16篇 |
1983年 | 9篇 |
1980年 | 7篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 13篇 |
1975年 | 8篇 |
1974年 | 9篇 |
1971年 | 7篇 |
1970年 | 6篇 |
1969年 | 9篇 |
排序方式: 共有1927条查询结果,搜索用时 15 毫秒
21.
AJ Chittick 《Australian veterinary journal》2016,94(11):426-426
22.
23.
M. Joscht M. Martin M. Henin J. F. Nisolle N. Kirschvink A. Dugdale B. Godart H. Coulon V. Simon F. Hontoir R. Graffin Y. De Raeve J. M. Vandeweerd 《Anatomia, histologia, embryologia》2016,45(6):443-449
External iliac artery atherosclerotic disease and aneurism occur in man. For treatment, imaging is required to facilitate minimally invasive introduction and advancement of stents within the intended vessels. Sheep are commonly used to test and improve stents. However, little information is published regarding the angiographic anatomy of the iliac arteries in the ovine species. The objective of this study was to describe the angiographic anatomy of the iliac arteries in the sheep. Computed tomography (CT) angiography and gross anatomical dissection were performed in, respectively, 10 and 43 adult ewes. Diameters and lengths of the arteries were measured. In comparison with man, salient anatomical differences were identified in the sheep: (1) the absence of common iliac arteries, (2) the common trunk at the origin of internal iliac arteries and (3) the location of the bifurcation of the external iliac arteries into femoral arteries in the pelvis (not in the limb). External iliac arteries in this series of sheep were 86 mm long in average and had a mean diameter of 7.5 mm. Lengths of arteries are only slightly different between man and sheep, while diameters are rather similar. Therefore, the sheep model appears to be sufficiently similar to man to test stent properties. This study provides useful reference images and measures of lengths and diameters of relevant arteries that could be applied to research with ovine models. 相似文献
24.
25.
Tuntivanich N Petersen-Jones SM Steibel JP Johnson C Forcier JQ 《Veterinary ophthalmology》2007,10(1):2-5
OBJECTIVE: The objectives of this study were to document the development of axial globe length (AGL) in normal mesocephalic cross-bred dogs between 2 and 52 weeks of age, to determine a relationship between AGL and age, and derive an equation to predict AGL in normal mesocephalic cross-bred dogs. ANIMALS STUDIED AND PROCEDURE: The AGL of twenty normal mesocephalic cross-bred dogs was measured at 12 time points from 2 to 52 weeks of age using B-scan ultrasonography. RESULTS: The mean (+/- SEM) AGL increased from 12.65 mm (+/- 0.18) at 2 weeks of age to 19.52 mm (+/- 0.18) at 52 weeks of age. The correlation between AGL and age was evaluated by fitting possible variables to a regression pattern. A linear model of natural logarithmic-transformed value of AGL (mm) and age (week) was established. Side (left or right eye) and gender did not correlate with development of AGL. CONCLUSIONS: A reverse transformation of the formula can be used to predict AGL in mesocephalic cross-bred dogs: AGL = 10.847 * age in weeks 0.1653. 相似文献
26.
Since its detection in 2001 the human Metapneumovirus (HMPV), a member of the Paramyxoviridae family, was observed to be a serious pathogen in human respiratory infections during childhood. Meanwhile, several animal models have been established to study the virus-host interactions and pathogenic effects. Mainly, small laboratory animals like mice and cotton rats have been used, although the usage of these two species for HMPV research is controversially discussed and contradictious results were obtained by different groups. Further trials with ferrets, hamsters and non human primates were performed revealing different success in their individual usage. In this review we present the different animal models, summarize their advantages and disadvantages, and discuss the controversial results from different studies. 相似文献
27.
28.
29.
Changyao Shan Baishu Li Li Li Xin Du Yonglin Ren Simon J. McKirdy Tao Liu 《Pest management science》2023,79(12):4942-4951
30.
Jilli Crosby BVetMed DVM Karen Humm MA VetMB MSc DACVECC DECVECC Simon D. Cook BSc BVSc MVetMed DACVECC DECVECC 《Journal of Veterinary Emergency and Critical Care》2023,33(1):91-97