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   1781篇
  免费   104篇
  国内免费   22篇
耳鼻咽喉   1篇
儿科学   151篇
妇产科学   18篇
基础医学   214篇
口腔科学   47篇
临床医学   165篇
内科学   386篇
皮肤病学   25篇
神经病学   35篇
特种医学   473篇
外科学   161篇
综合类   31篇
预防医学   56篇
眼科学   13篇
药学   55篇
中国医学   3篇
肿瘤学   73篇
  2022年   4篇
  2021年   7篇
  2020年   10篇
  2019年   7篇
  2018年   16篇
  2017年   10篇
  2016年   24篇
  2015年   31篇
  2014年   29篇
  2013年   58篇
  2012年   25篇
  2011年   30篇
  2010年   75篇
  2009年   63篇
  2008年   39篇
  2007年   31篇
  2006年   42篇
  2005年   33篇
  2004年   23篇
  2003年   22篇
  2002年   24篇
  2001年   16篇
  2000年   32篇
  1999年   31篇
  1998年   134篇
  1997年   123篇
  1996年   127篇
  1995年   94篇
  1994年   76篇
  1993年   82篇
  1992年   27篇
  1991年   25篇
  1990年   18篇
  1989年   61篇
  1988年   45篇
  1987年   51篇
  1986年   47篇
  1985年   51篇
  1984年   29篇
  1983年   33篇
  1982年   35篇
  1981年   21篇
  1980年   36篇
  1979年   15篇
  1978年   15篇
  1977年   20篇
  1976年   24篇
  1975年   26篇
  1971年   2篇
  1966年   2篇
排序方式: 共有1907条查询结果,搜索用时 15 毫秒
1.
Pediatric knee MR imaging: pattern of injuries in the immature skeleton   总被引:3,自引:0,他引:3  
  相似文献   
2.
3.
We report an adult female with a rare giant choledochal cyst. The patient presented following a normal pregnancy with the classical triad of an abdominal mass associated with jaundice and right upper quadrant abdominal pain. The cyst was excised using an intramural technique and biliary reconstruction achieved with a Roux-en-Y hepaticojejunostomy. Our patient has remained well with no evidence of malignancy over a 12 year review period. The aetiology and current management of this condition are discussed.  相似文献   
4.
5.
6.
Na+ dependence of in vitro pancreatic amylase release   总被引:1,自引:0,他引:1  
  相似文献   
7.
The objective was to test the hypothesis that the optimal cryoprotective agent for cryopreservation of human spermatozoa would be a solute for which cells have the highest plasma membrane permeability, resulting in the least amount of volume excursion during its addition and removal. To test this hypothesis, theoretical simulations were performed using membrane permeability coefficients to predict optimal procedures for the addition and removal of a cryoprotectant. Simulations were performed using data from four different cryoprotectants: (i) glycerol, (ii) dimethyl sulphoxide, (iii) propylene glycol and (iv) ethylene glycol. Thermodynamic formulations were applied to determine approaches for the addition and removal of 1 M and 2 M final concentrations of cryoprotectant, allowing the spermatozoa to maintain a cell volume within their osmotic tolerance limits. Based on these data, ethylene glycol was predicted to be optimal for minimizing volume excursions among the solutes evaluated. These predictions were then experimentally tested using glycerol as the control cryoprotectant and ethylene glycol as the experimental cryoprotectant. The results indicate that there was a higher (P < 0.05) recovery of motile spermatozoa after cryopreservation when using 1 M ethylene glycol than with 1 M glycerol, supporting the hypothesis that use of the cryoprotectant for which the cell has the highest permeability will result in higher cell survival.   相似文献   
8.
Summary We have previously shown that specific antibodies (Mab 32/Ab 301) against tumour necrosis factor (TNF) enhance its antiviral activity in vaccinia virus-infected mice. In the present study, TNF alone was found to have antiviral activity against herpes simplex virus-1 (HSV-1). Antibody enhancement was found, both in vivo and in vitro, at lower TNF doses. The magnitude of the TNF-induced antiviral response was dependent upon the genetic background of the mouse. C57BL/6 mice were very sensitive to the antiviral activity of TNF, which was inhibited by the free radical scavenger butylated hydroxyanisole (BHA). TNF plus Mab 32 induced a significant antiviral effect in L929 cells which was associated with pronounced CPE. The CPE was largely reversed in the presence of BHA, and furthermore, TNF antiviral activity was significantly reversed in the presence of BHA. Specific inhibitors of nitric oxide synthetase, lipoxygenase or cyclo-oxygenase did not influence either the CPE or growth kinetics of HSV-1, suggesting that neither reactive nitrogen intermediates nor arachidonic acid metabolites were involved in the antiviral mechanism of TNF. This, together with observed increases in Cu/Zn SOD levels in virus infected cells, suggests that reactive oxygen intermediates may have a role in the direct control of HSV-1 growth and that free radicals may play a part in the antiviral activity induced by TNF.  相似文献   
9.
A total of 447 cervical or vaginal specimens were inoculated in parallel onto peptone-starch-dextrose (PSD) and Columbia colistin (10 mg/ml)-nalidixic acid (15 mug/ml) (CNA) agar and were incubated for 48 h at 35 degrees C in an atmosphere with 2 to 10% CO2. One hundred (22.4%) of the cultures were positive for Haemophilus vaginalis. Forty-eight of the isolates were recovered from both PSD and Columbia CNA agar, five from PSD only, and 47 from Columbia CNA agar only (P less than 0.001). On Columbia CNA agar, 76 of the isolates were detected after 24 h of incubation, and the remainder were detected within 4 days of incubation.  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