首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6548篇
  免费   3493篇
林业   176篇
农学   431篇
  1295篇
综合类   145篇
农作物   93篇
水产渔业   2498篇
畜牧兽医   4146篇
园艺   10篇
植物保护   1247篇
  2021年   127篇
  2020年   464篇
  2019年   1020篇
  2018年   893篇
  2017年   932篇
  2016年   922篇
  2015年   807篇
  2014年   792篇
  2013年   968篇
  2012年   447篇
  2011年   471篇
  2010年   594篇
  2009年   238篇
  2008年   233篇
  2007年   85篇
  2006年   104篇
  2005年   88篇
  2004年   101篇
  2003年   92篇
  2002年   107篇
  2001年   75篇
  2000年   111篇
  1999年   18篇
  1997年   12篇
  1996年   6篇
  1995年   7篇
  1994年   11篇
  1993年   9篇
  1992年   9篇
  1991年   12篇
  1990年   11篇
  1989年   7篇
  1988年   7篇
  1987年   7篇
  1986年   11篇
  1985年   8篇
  1984年   7篇
  1983年   13篇
  1979年   9篇
  1978年   17篇
  1977年   10篇
  1975年   12篇
  1974年   11篇
  1973年   10篇
  1972年   12篇
  1971年   9篇
  1970年   10篇
  1969年   6篇
  1968年   8篇
  1961年   5篇
排序方式: 共有10000条查询结果,搜索用时 209 毫秒
141.
Nanotechnology applications in medicine have seen a tremendous growth in the past decade and are being employed to enhance the stability and bioavailability of lipophilic substances, such as florfenicol. This study aimed to examine the pharmacokinetic properties of the formulated oil‐in‐water florfenicol‐loaded nanoemulsion (FF‐NE). FF‐NE and florfenicol control (Nuflor®) were administered to the pigs at a dose of 20 mg/kg. Nanoemulsion formulation of florfenicol was highly influenced in vivo plasma profile. The in vivo absorption study in pigs indicated that Cmax (14.54 μg/mL) was significantly higher in FF‐NE, 3.42 times higher than the marketed formulation. In comparison with the control group, the relative bioavailability of formulated nanoemulsion was up to 134.5%. Assessment of bioequivalence using log‐transformed data showed that the 90% confidence intervals (90% CI) of Cmax and AUC0–∞ were 2.48–4.60 and 1.21–1.72, respectively.  相似文献   
142.
143.
144.
145.
146.
The aim of this study was to investigate the variability of the internal pudendal artery. Two hundred and thirty‐two pelvic halves from 116 adult dogs were examined. Twenty‐six anatomical variations were found, thirteen occurring in more than 5% of the dogs. Anatomical variations were grouped in relation to the origin of the prostatic/vaginal arteries, middle rectal artery, urethral artery, ventral perineal and caudal rectal arteries. The chi‐squared test was used to analyse differences in sex, side of the body, profile and size, and the results were considered statistically significant when  0.05. An identical vascular pattern in both hemipelvises was found for most of the anatomical variations described.  相似文献   
147.
The aim of this study was to analyse and describe the variability of the umbilical artery. Two hundred and thirty‐two pelvic halves from 116 adult dogs were examined. To study the permeability of the umbilical artery, ten adult dogs, nine newborns and thirteen foetuses between 35 and 50 days of gestation were also used. In relation to the origin of the umbilical artery, six anatomical variations were found. From which five involved a cranial (= 4) or caudal (= 1) relocation of its origin, and in one case (= 1), the umbilical artery arose from the median sacral artery. In eight cases, the umbilical artery gave off the prostatic (= 1) or vaginal (= 7) arteries. The permeability of the umbilical artery was the most significant anatomical variation: permeability was detected in 45% (106 of 232 pelvic halves) of all cases, from which 36 were males and 70 females. Interestingly, an equal vascular permeability in both hemipelvises was found for 82% of the dogs, thus additional data related to such feature of the umbilical artery was also recorded. In accordance with the statistical study, the main anatomical variations described showed significant values for gender, side of the body, size and profile variables.  相似文献   
148.
This study aims to enhance the anatomical knowledge of the ear of the adult quail (Coturnix coturnix) through the creation of a scaled 3D model utilizing data from micro‐CT images. In addition, 17 annotated histological sections of the quail's ear are aligned to their 3D position in the model. The resulting anatomical atlas provides an intuitive insight into the 3D anatomy and can be used for medical education. The model also allows measuring anatomical structures and can thus serve as reference for the quail's auricular anatomy and as a basis to evaluate clinical diagnostic imaging results.  相似文献   
149.
150.
A 5.5‐year‐old, intact male Rottweiler dog was admitted with a history of multifocal nodular tongue lesions which progressively deteriorated during the previous year. Physical examination revealed several reddish nodules with central depression on the surface of the tongue in an otherwise healthy dog. Clinicopathologic abnormalities included eosinophilia and hyperproteinemia. Lingual nodule cytopathology, histopathology, and immunohistochemistry revealed Leishmania spp. amastigotes and a severe granulomatous glossitis. The dog was also seroreactive to L infantum antigens by an indirect immunofluorescence assay. Clinical reevaluation 3 months after the institution of treatment with allopurinol and miltefosine indicated that the nodular lesions had completely regressed. In endemic areas, lingual nodular lesions may rarely be the sole clinical sign of canine leishmaniosis. Standard medical treatment may provide an excellent prognosis.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号