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   1455445篇
  免费   81414篇
  国内免费   1852篇
耳鼻咽喉   19186篇
儿科学   46865篇
妇产科学   36275篇
基础医学   199158篇
口腔科学   38851篇
临床医学   119226篇
内科学   281940篇
皮肤病学   31416篇
神经病学   114396篇
特种医学   56594篇
外国民族医学   203篇
外科学   215558篇
综合类   24930篇
现状与发展   1篇
一般理论   314篇
预防医学   115982篇
眼科学   32743篇
药学   111176篇
  7篇
中国医学   4432篇
肿瘤学   89458篇
  2021年   11155篇
  2019年   11878篇
  2018年   38504篇
  2017年   28958篇
  2016年   32231篇
  2015年   16918篇
  2014年   21333篇
  2013年   31168篇
  2012年   51177篇
  2011年   66666篇
  2010年   43674篇
  2009年   33882篇
  2008年   60310篇
  2007年   65399篇
  2006年   45793篇
  2005年   45438篇
  2004年   44089篇
  2003年   43200篇
  2002年   39783篇
  2001年   66705篇
  2000年   69137篇
  1999年   56657篇
  1998年   13578篇
  1997年   11783篇
  1996年   11687篇
  1995年   10923篇
  1994年   9847篇
  1993年   9268篇
  1992年   40536篇
  1991年   38705篇
  1990年   38064篇
  1989年   36252篇
  1988年   32690篇
  1987年   31658篇
  1986年   29875篇
  1985年   27992篇
  1984年   20299篇
  1983年   17075篇
  1982年   9325篇
  1979年   18221篇
  1978年   12205篇
  1977年   10994篇
  1976年   9583篇
  1975年   10971篇
  1974年   12820篇
  1973年   12489篇
  1972年   11887篇
  1971年   11184篇
  1970年   10294篇
  1969年   10039篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Reduction of transmission of human immunodeficiency virus type 1 (HIV-1) through human milk is needed. Alkyl sulfates such as sodium dodecyl sulfate (SDS) are microbicidal against HIV-1 at low concentrations, have little to no toxicity, and are inexpensive. The authors have reported that treatment of HIV-1-infected human milk with < or = 1% (10 mg/mL) SDS for 10 minutes inactivates cell-free and cell-associated virus. The SDS can be removed with a commercially available resin after treatment without recovery of viral infectivity. In this article, the authors report results of selective biochemical analyses (ie, protein, immunoglobulins, lipids, cells, and electrolytes) of human milk subjected to SDS treatment and removal. The SDS treatment or removal had no significant effects on the milk components studied. Therefore, the use of alkyl sulfate microbicides to treat milk from HIV-1-positive women may be a simple, practical, and nutritionally sound way to prevent or reduce transmission of HIV-1 while still feeding with mother's own milk.  相似文献   
992.
Efficient high-frequency body coil for high-field MRI.   总被引:1,自引:0,他引:1  
The use of body coils is favored for homogeneous excitation, and such coils are often paired with surface coils or arrays for sensitive reception in many MRI applications. While the body coil's physical size and resultant electrical length make this circuit difficult to design for any field strength, recent efforts to build efficient body coils for applications at 3T and above have been especially challenging. To meet this challenge, we developed an efficient new transverse electromagnetic (TEM) body coil and demonstrated its use in human studies at field strengths up to 4 T. Head, body, and breast images were acquired within peak power constraints of <8 kW. Bench studies indicate that these body coils are feasible to 8 T. RF shimming was used to remove a high-field-related cardiac imaging artifact in these preliminary studies. P41RR13230  相似文献   
993.

Background  

Skin and soft tissue infections are increasingly prevalent clinical problems, and it is important for health care practitioners to be well trained in how to treat skin abscesses. A realistic model of abscess incision and drainage will allow trainees to learn and practice this basic physician procedure.  相似文献   
994.
995.
A common distal radio-ulnar joint (DRUJ) stabilisation procedure uses a tendon graft running from the lip of the radial sigmoid notch to the ulnar fovea and through a bony tunnel to the ulnar shaft, before being wrapped round the distal ulna and sutured to itself. Such graft fixation can be challenging and requires a considerable tendon length. The graft length could be reduced by fixing the graft to the ulna using a bone anchor or interference screw. The aim of this study was to compare the strength of three distal ulna graft fixation methods (tendon wrapping and suturing, bone anchor and interference screw). Four human cadaveric ulnae were used. A tendon strip was run through a tunnel in the distal ulna and secured by: (1) wrapping round the shaft and suturing it to itself, (2) a bone anchor and (3) an interference screw in the bone tunnel. Load to failure was determined using a custom-made apparatus and an Instron machine. Maximum failure load was highest for the bone anchor fixation (99.3 ± 23.7 N) followed by the suturing (96.2 ± 12.1 N), and the interference screw fixation (46.9 ± 5.6 N). There was no significant difference between the tendon suturing and bone anchor methods, but the tendon suturing was statistically significantly higher compared to the interference screw (P = 0.028). In performing anatomical stabilisation of the DRUJ fixation of the tendon graft to the distal ulna with a bone anchor provides the most secure fixation. This may make the stabilisation technique less demanding and require a smaller tendon graft.  相似文献   
996.
997.
998.
999.
1000.
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