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   1286494篇
  免费   94672篇
  国内免费   2026篇
耳鼻咽喉   18573篇
儿科学   43217篇
妇产科学   38201篇
基础医学   187646篇
口腔科学   36108篇
临床医学   108947篇
内科学   253357篇
皮肤病学   26797篇
神经病学   99833篇
特种医学   50525篇
外国民族医学   366篇
外科学   200140篇
综合类   26803篇
现状与发展   1篇
一般理论   306篇
预防医学   92944篇
眼科学   29436篇
药学   98367篇
  1篇
中国医学   2572篇
肿瘤学   69052篇
  2018年   12118篇
  2016年   10366篇
  2015年   11887篇
  2014年   16422篇
  2013年   24918篇
  2012年   34186篇
  2011年   36603篇
  2010年   21587篇
  2009年   20316篇
  2008年   35562篇
  2007年   38600篇
  2006年   39173篇
  2005年   38478篇
  2004年   37103篇
  2003年   36087篇
  2002年   35581篇
  2001年   58565篇
  2000年   59971篇
  1999年   51014篇
  1998年   14361篇
  1997年   12916篇
  1996年   13173篇
  1995年   12392篇
  1994年   11799篇
  1993年   10882篇
  1992年   41051篇
  1991年   40417篇
  1990年   39923篇
  1989年   38757篇
  1988年   36132篇
  1987年   35373篇
  1986年   33748篇
  1985年   32151篇
  1984年   23942篇
  1983年   20828篇
  1982年   12382篇
  1981年   10937篇
  1979年   22641篇
  1978年   15880篇
  1977年   13733篇
  1976年   12975篇
  1975年   14202篇
  1974年   16688篇
  1973年   16079篇
  1972年   15326篇
  1971年   14237篇
  1970年   13218篇
  1969年   12732篇
  1968年   11980篇
  1967年   10484篇
排序方式: 共有10000条查询结果,搜索用时 26 毫秒
111.
112.
113.
Die Ophthalmologie - Die Filtrationsverfahren sind im Gegensatz zu allen anderen Glaukomoperationen mit einer biomikroskopisch sichtbaren Wundheilung assoziiert, sodass eine Vielzahl von...  相似文献   
114.
115.
116.
Synthetic amorphous silica (SAS) in its nanosized form is now used in food applications although the potential risks for human health have not been evaluated. In this study, genotoxicity and oxidative DNA damage of two pyrogenic (NM‐202 and 203) and two precipitated (NM‐200 and ‐201) nanosized SAS were investigated in vivo in rats following oral exposure. Male Sprague Dawley rats were exposed to 5, 10, or 20 mg/kg b.w./day for three days by gavage. DNA strand breaks and oxidative DNA damage were investigated in seven tissues (blood, bone marrow from femur, liver, spleen, kidney, duodenum, and colon) with the alkaline and the (Fpg)‐modified comet assays, respectively. Concomitantly, chromosomal damage was investigated in bone marrow and in colon with the micronucleus assay. Additionally, malondialdehyde (MDA), a lipid peroxidation marker, was measured in plasma. When required, a histopathological examination was also conducted. The results showed neither obvious DNA strand breaks nor oxidative damage with the comet assay, irrespective of the dose and the organ investigated. Similarly, no increases in chromosome damage in bone marrow or lipid peroxidation in plasma were detected. However, although the response was not dose‐dependent, a weak increase in the percentage of micronucleated cells was observed in the colon of rats treated with the two pyrogenic SAS at the lowest dose (5 mg/kg b.w./day). Additional data are required to confirm this result, considering in particular, the role of agglomeration/aggregation of SAS NMs in their uptake by intestinal cells. Environ. Mol. Mutagen. 56:218–227, 2015. © 2014 Wiley Periodicals, Inc.  相似文献   
117.
118.
119.
120.
Women with pre-eclampsia have an increased risk of cardiovascular disease later in life. The aim of the study was to establish the presence and pattern of arterial stiffness in women previously with pre-eclampsia from a semi-rural region of South Africa. This was a prospective longitudinal study which involved 36 previously pre-eclamptic women and 86 non-pregnant controls (NPC) who had a past history of non-complicated pregnancy. Maternal wave reflection (augmentation index) and carotid-femoral pulse wave velocity were assessed noninvasively, using applanation tonometry with the SphygmoCor device. Endothelial function was assessed by EndoPAT 2000 device; pneumatic probes were fitted to the index fingers; induced flow-mediated reactive hyperemia; the ratio of the readings before and after occlusion was then used to calculate the score, the reactive hyperemia index (RHI) as a measure of endothelial function.

Pulse wave velocity remained significantly higher in previously pre-eclamptic women than non-pregnant controls up to three months after delivery (p < 0.05), then it reduced to nonsignificant values. All blood pressure indices (central and brachial pressures), were higher in previously pre-eclamptic women as compared to nonpregnant controls up to one year postpartum.

Regional (aortic) arterial stiffness, though it persists for some time after delivery, is transitory in previously pre-eclamptic women from the rural Africa setting. However, their increase blood pressure is an indication of compromised arterial compliance in women previously with pre-eclampsia.  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