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   6176篇
  免费   3466篇
林业   173篇
农学   422篇
基础科学   1篇
  1270篇
综合类   47篇
农作物   94篇
水产渔业   2479篇
畜牧兽医   3912篇
园艺   2篇
植物保护   1242篇
  2022年   3篇
  2021年   120篇
  2020年   462篇
  2019年   1015篇
  2018年   888篇
  2017年   929篇
  2016年   920篇
  2015年   808篇
  2014年   790篇
  2013年   954篇
  2012年   437篇
  2011年   452篇
  2010年   584篇
  2009年   237篇
  2008年   212篇
  2007年   60篇
  2006年   90篇
  2005年   81篇
  2004年   85篇
  2003年   85篇
  2002年   103篇
  2001年   67篇
  2000年   103篇
  1999年   9篇
  1998年   4篇
  1997年   11篇
  1996年   6篇
  1995年   8篇
  1994年   7篇
  1993年   8篇
  1991年   3篇
  1990年   5篇
  1988年   3篇
  1986年   3篇
  1985年   3篇
  1984年   5篇
  1983年   3篇
  1982年   3篇
  1980年   4篇
  1978年   7篇
  1977年   5篇
  1975年   5篇
  1970年   6篇
  1968年   4篇
  1966年   2篇
  1957年   2篇
  1947年   3篇
  1944年   2篇
  1943年   3篇
  1893年   2篇
排序方式: 共有9642条查询结果,搜索用时 15 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