首页 | 官方网站   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   9578篇
  免费   576篇
  国内免费   39篇
医药卫生   10193篇
  2023年   66篇
  2022年   59篇
  2021年   255篇
  2020年   159篇
  2019年   231篇
  2018年   273篇
  2017年   217篇
  2016年   223篇
  2015年   276篇
  2014年   385篇
  2013年   477篇
  2012年   769篇
  2011年   788篇
  2010年   410篇
  2009年   374篇
  2008年   656篇
  2007年   673篇
  2006年   592篇
  2005年   643篇
  2004年   555篇
  2003年   499篇
  2002年   477篇
  2001年   99篇
  2000年   86篇
  1999年   86篇
  1998年   85篇
  1997年   57篇
  1996年   57篇
  1995年   68篇
  1994年   57篇
  1993年   40篇
  1992年   50篇
  1991年   48篇
  1990年   48篇
  1989年   47篇
  1988年   35篇
  1987年   37篇
  1986年   35篇
  1985年   25篇
  1984年   23篇
  1983年   25篇
  1982年   18篇
  1981年   8篇
  1980年   17篇
  1979年   9篇
  1976年   9篇
  1974年   8篇
  1973年   6篇
  1970年   7篇
  1968年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Chitosan oligosaccharide (C) was functionalized with l-arginine (A) and short hydrocarbon chains (C8) to design an amphiphilic copolymer, henceforth CAC8, leading to microparticles (MPs) consisting of an arginine-decorated hydrophilic shell and inner hydrophobic domains allowing the encapsulation of high amount hydrophobic drugs such as sorafenib tosylate (>10% w/w). l-arginine side chains were selected in order to impart the final MPs enhanced transcorneal penetration properties, thus overcoming the typical biological barriers which hamper the absorption of drugs upon topical ocular administration. The mucoadhesive properties and drug release profile of the CAC8 MPs (CAC8-MPs) were studied, showing that CAC8-MPs can strongly interact with mucin, and thus gradually release their payload in situ to potentially improve the bioavailability of the drug after topical administration. In vitro transcorneal studies also showed that CAC8-MPs are endowed with effective permeation enhancer ability combined with negligible toxicity.  相似文献   
3.
4.
5.
6.
7.
8.
ABSTRACT

This study aimed to compare the physical and physiological responses of young football players of different categories during small-sided games (SSGs) played on different pitch sizes. Forty-eight (24 U-13 and 24 U-14) athletes played a 3 vs. 3 + 1 SSG in two experimental conditions: regular (36 × 27 m) and large pitch sizes (40 × 29 m). The total distance covered, the distances covered at different speed zones (0 to 6.9 km/h, 6.9 to 14.3, and 14.3 to 21.4), maximum heart rate, and mean heart rate were recorded. The results showed that older athletes covered larger distances during SSGs (p = 0.001; d = 0.937; large effect) and lower distances at the lowest (0–6.9 km/h) speed zone (p = 0.001; d = 0.657; moderate-to-large effect). Neither the physical nor physiological variables (except for distance covered between 14.3 and 21.4 km/h) differed between pitch sizes. This result indicates that pitch size may not impact the physical or physiological responses of U-13 and U-14 players during SSGs, but differences between categories were found. In conclusion, the development of tactical skills may be desirable to better explore the available space in the same age categories.  相似文献   
9.
Hyalinizing trabecular tumors of the thyroid are rare and mostly benign epithelial neoplasms of follicular cell origin, which have recently been shown to be underpinned by the PAX8-GLIS3 fusion gene. In our study, we sought to investigate the potential oncogenic mechanisms of the PAX8-GLIS3 fusion gene. Forced expression of PAX8-GLIS3 was found to increase proliferation, clonogenic potential and migration of human nonmalignant thyroid (Nthy-ori 3-1) and embryonic kidney (HEK-293) cells. Moreover, in xenografts, Nthy-ori 3-1 PAX8-GLIS3 expressing cells generated significantly larger and more proliferative tumors compared to controls. These oncogenic effects were found to be mediated through activation of the Sonic Hedgehog (SHH) pathway. Targeting of smoothened (SMO), a key protein in the SHH pathway, using the small molecule inhibitor Cyclopamine partially reversed the increased proliferation, colony formation and migration in PAX8-GLIS3 expressing cells. Our data demonstrate that the oncogenic effects of the PAX8-GLIS3 fusion gene are, at least in part, due to an increased activation of the SHH pathway.  相似文献   
10.
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-23

京公网安备 11010802026262号