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   2229篇
  免费   212篇
  国内免费   49篇
耳鼻咽喉   11篇
儿科学   112篇
妇产科学   36篇
基础医学   248篇
口腔科学   80篇
临床医学   347篇
内科学   457篇
皮肤病学   253篇
神经病学   73篇
特种医学   211篇
外科学   186篇
综合类   114篇
预防医学   137篇
眼科学   13篇
药学   117篇
中国医学   5篇
肿瘤学   90篇
  2023年   17篇
  2022年   20篇
  2021年   37篇
  2020年   25篇
  2019年   27篇
  2018年   35篇
  2017年   49篇
  2016年   42篇
  2015年   41篇
  2014年   80篇
  2013年   96篇
  2012年   71篇
  2011年   81篇
  2010年   92篇
  2009年   87篇
  2008年   83篇
  2007年   119篇
  2006年   83篇
  2005年   81篇
  2004年   80篇
  2003年   63篇
  2002年   48篇
  2001年   56篇
  2000年   54篇
  1999年   33篇
  1998年   86篇
  1997年   71篇
  1996年   66篇
  1995年   54篇
  1994年   55篇
  1993年   48篇
  1992年   30篇
  1991年   34篇
  1990年   40篇
  1989年   47篇
  1988年   46篇
  1987年   31篇
  1986年   49篇
  1985年   39篇
  1984年   29篇
  1983年   25篇
  1982年   20篇
  1981年   18篇
  1980年   25篇
  1979年   17篇
  1978年   19篇
  1977年   14篇
  1976年   17篇
  1975年   15篇
  1974年   17篇
排序方式: 共有2490条查询结果,搜索用时 31 毫秒
1.
Haaga  JR; Beale  SM 《Radiology》1986,161(3):829-830
By injecting small amounts of CO2 through a needle, one can move bowel or bladder from the intended path of instruments during interventional procedures. The technique worked well in six of seven cases in the pelvis and retroperitoneum; it was not effective in the mediastinum or midabdomen (n = 6).  相似文献   
2.
3.
Topical Metronidazole Gel   总被引:1,自引:0,他引:1  
Ten putrid-smelling decubitus ulcers were successfully treated with metronidazole gel. Anaerobes were cultured from five ulcers and Wood's light examination was positive in four ulcers before treatment. The odor was eliminated after 36 hours of therapy. All results of post-treatment cultures of anaerobes and Wood's light examinations were negative.  相似文献   
4.
Motility disorders of the gastrointestinal (GI) tract have traditionally been diagnosed by excluding mechanical small-bowel obstruction. In order to diagnose GI motility disorders in a positive fashion, small-bowel manometry was performed on 15 patients who were referred to the authors with intestinal motility disorders. Intestinal manometry was performed after first positioning a 200-cm multilumen tube into the small intestine. Ports located at 10-cm intervals were perfused with sterile water and connected to pressure transducers to record intraluminal pressures with a multichannel chart recorder. This low compliance water perfusion manometry system allowed examination of both fasting and postprandial motility. Intestinal manometry was able to assist in the diagnosis of two patients that had true mechanical small-bowel obstruction. One patient had a stenosis of the gastrojejunostomy and three patients had a functional gastric outlet obstruction secondary to a motility disorder in the Roux limb. One patient had a functional obstruction from a reversed jejunal loop and eight patients were identified as having intestinal pseudo-obstruction. We found intestinal manometry was a helpful adjunct in the diagnosis of GI motility disorders.  相似文献   
5.
The stability of phenytoin in blood collected in plain and serum separator tubes (SSTs) was investigated under simulated storage and transport conditions. The drug was generally more stable in plain collection tubes than in SSTs. No degradation occurred in plain red-top tubes or in refrigerated SSTs, but clinically significant degradation was present in SSTs stored at room temperature (25 degrees C) and at elevated temperature (32 degrees C) 24 h after collection. The mean loss was 17.9% at 25 degrees C and 25.9% at 32 degrees C. It is recommended that if blood is to be transported or stored in SSTs, the samples be refrigerated unless assay can be performed within 8 h.  相似文献   
6.
外科医生和手术室人员经常接触手术设备产生的烟气,病人也会暴露于烟气中,特别是腹腔镜手术中产生的烟气滞留于腹腔内这一密闭空间并被吸收.这些烟气是一种与香烟烟气相似的毒性物质,然而对这种毒性物质的影响还未引起足够重视.应该采取必要措施尽可能减少手术中烟气的不良影响.  相似文献   
7.
8.
Cardiac magnetic resonance (MR) imaging has developed rapidly to rival echocardiography as a noninvasive imaging modality. Anatomic detail may exceed that currently available using echocardiography techniques, and the ability to image moving protons may compete with Doppler color flow mapping in detecting valvular diseases and shunts. Because of the considerable clinical experience with echocardiography, as angled MR imaging planes become available as standard software packages, it may be useful for MR cardiac imaging to use standard, accepted echocardiographic nomenclature and imaging planes. This article describes the principles used to obtain long and short axis MR images that are comparable with echocardiographic imaging planes. Diagrams and illustrations are provided to orient the viewer using nomenclature common to echocardiography. These views may eventually be useful for functional analysis of the left ventricle and for detection and evaluation of valvular heart disease and intracardiac shunts.  相似文献   
9.
10.
The activities of several flavonoids and the related nonflavonoid compound epicatechin were compared with respect to Cu(II)-induced strand scission of DNA by using two different assays. The same series of compounds was used to study the stoichiometry of Cu(II) reduction in the absence of DNA. The compounds were compared for their ability to generate superoxide, hydrogen peroxide and the Cu(II)-dependent production of hydroxyl radicals. Flavonoids were examined to assess the production of a charge-transfer complex with Cu and the rate of decay of the complexes were compared. All the compounds tested had some ability to cause DNA strand scission in the presence of Cu(II), with myricetin being the most active and galangin the least active. The ability to cause such scission correlated with the rate of decay of the charge-transfer complex, the ability to generate active oxygen species and with the stoichiometry of Cu(II) binding. Analysis of the data in the light of the structural differences between the flavonoids led to a discussion of alternative Cu(II)-sequestering mechanisms.  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