全文获取类型
收费全文 | 5672篇 |
免费 | 340篇 |
国内免费 | 1篇 |
专业分类
林业 | 1039篇 |
农学 | 164篇 |
基础科学 | 10篇 |
1209篇 | |
综合类 | 538篇 |
农作物 | 145篇 |
水产渔业 | 189篇 |
畜牧兽医 | 2193篇 |
园艺 | 120篇 |
植物保护 | 406篇 |
出版年
2023年 | 35篇 |
2022年 | 37篇 |
2021年 | 82篇 |
2020年 | 78篇 |
2019年 | 42篇 |
2018年 | 187篇 |
2017年 | 176篇 |
2016年 | 158篇 |
2015年 | 137篇 |
2014年 | 150篇 |
2013年 | 368篇 |
2012年 | 321篇 |
2011年 | 347篇 |
2010年 | 163篇 |
2009年 | 145篇 |
2008年 | 283篇 |
2007年 | 311篇 |
2006年 | 303篇 |
2005年 | 260篇 |
2004年 | 254篇 |
2003年 | 274篇 |
2002年 | 216篇 |
2001年 | 179篇 |
2000年 | 173篇 |
1999年 | 106篇 |
1998年 | 35篇 |
1997年 | 37篇 |
1996年 | 44篇 |
1995年 | 73篇 |
1994年 | 43篇 |
1993年 | 21篇 |
1992年 | 26篇 |
1991年 | 23篇 |
1990年 | 30篇 |
1989年 | 25篇 |
1988年 | 28篇 |
1987年 | 16篇 |
1986年 | 33篇 |
1985年 | 33篇 |
1984年 | 24篇 |
1983年 | 22篇 |
1980年 | 27篇 |
1979年 | 15篇 |
1978年 | 16篇 |
1977年 | 25篇 |
1975年 | 14篇 |
1973年 | 18篇 |
1966年 | 16篇 |
1955年 | 14篇 |
1941年 | 14篇 |
排序方式: 共有6013条查询结果,搜索用时 0 毫秒
991.
Adarkwah Charles Obeng-Ofori Daniel Ulrichs Christian Schöller Matthias 《植物病害和植物保护杂志》2017,124(3):255-267
Journal of Plant Diseases and Protection - Farmers in Africa in general have repeatedly prioritized the urgent need for improved methods of storage pest control. Laboratory studies were evaluated... 相似文献
992.
The effect of repeated eye examinations and breeding advice on the prevalence and incidence of cataracts and progressive retinal atrophy in German dachshunds over a 13‐year period 下载免费PDF全文
993.
994.
Objective
Myxomatous mitral valve disease (MMVD) induces progressive left atrial (LA) enlargement. The LA modulates left ventricular filling and performance through its reservoir, conduit, and contractile function. Assessment of LA size and function may provide valuable information on the level of cardiac compensation. Left atrial function in dogs with naturally occurring MMVD remains largely unexplored. The objective of this study was to evaluate LA volume and function in dogs with naturally occurring MMVD.Animals
This prospective study included 205 client-owned dogs of different breeds, 114 healthy dogs, and 91 dogs with MMVD of different disease severities.Methods
Using two-dimensional echocardiography, the biplane area-length method was applied to assess LA volume and calculate volumetric indices of LA reservoir, conduit, and contractile function.Results
Left atrial volume and LA stroke volume increased, whereas LA reservoir and contractile function decreased with increasing disease severity. A maximal LA volume <2.25mL/kg was the optimal cut off identified for excluding congestive heart failure in dogs with chronic MMVD with a sensitivity of 96% and a specificity of 100%. An active LA emptying fraction <24% and/or a LA expansion index <126% were suggestive of congestive heart failure in dogs with chronic MMVD with a sensitivity of 77% and a specificity of 89% and a sensitivity of 82% and a specificity of 82%, respectively.Conclusion
Dogs with MMVD appear to have larger LA volumes with poorer LA function. Deteriorating LA function, characterized by a decreasing reservoir and active contractile function, was evident in dogs with MMVD with increasing disease severity. 相似文献995.
Markers of Oxidative Stress in Dogs with Myxomatous Mitral Valve Disease are Influenced by Sex,Neuter Status,and Serum Cholesterol Concentration 下载免费PDF全文
996.
Evaluation of reticulocyte hemoglobin content (RET‐He) in the diagnosis of iron‐deficient erythropoiesis in dogs 下载免费PDF全文
Jannika Fuchs Andreas Moritz Esther Grußendorf Jörg Lechner Felix Neuerer Rafael Nickel Thomas Rieker Claudia Schwedes Dennis B. DeNicola James Russell Natali Bauer 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2017,46(4):558-568
Background
Reticulocyte hemoglobin content provided by the Siemens ADVIA (CHr) is an established marker of iron deficiency. The IDEXX ProCyte Dx hematology analyzer now provides a similar variable, reticulocyte hemoglobin equivalent (RET‐He).Objectives
The objective was to evaluate RET‐He and its diagnostic utility in dogs, and to calculate a cutoff value for diagnosing iron‐deficient erythropoiesis (IDE). Furthermore, the prevalence of RET‐He values below this cutoff value was established.Methods
One hundred and seventy‐one CBCs of healthy dogs were used to establish a RI. Stability of RET‐He was evaluated by repeated measurements over 48 hours (n = 10). The 25‐run coefficient of variation (CV) was calculated, and correlation and bias between measurements of RET‐He and CHr were assessed (n = 190). A cutoff value for diagnosing IDE was calculated. The utility of RET‐He in the detection of IDE was evaluated in 123 dogs. The prevalence of low RET‐He values was assessed retrospectively in a multicenter study (2012–2014) under participation of 7 veterinary clinics.Results
Reticulocyte hemoglobin equivalent with an RI of 22.2 to 28.6 pg was statistically stable over 48 hours (P = .10). The CV was 1.8%. A fair correlation (ρ = 0.74) between RET‐He and CHr with a small bias of ?0.6 pg was found. The cutoff value for diagnosing IDE was 20.9 pg (sensitivity: 85%; specificity: 99%). The prevalence of RET‐He values below 20.9 pg was 10.3% (1084/10,553 dogs).Conclusions
RET‐He on the ProCyte Dx is a precise screening tool in dogs to detect iron‐deficient erythropoiesis. 相似文献997.
998.
999.
1000.