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   3422篇
  免费   202篇
  国内免费   8篇
耳鼻咽喉   22篇
儿科学   221篇
妇产科学   77篇
基础医学   386篇
口腔科学   38篇
临床医学   235篇
内科学   559篇
皮肤病学   49篇
神经病学   139篇
特种医学   162篇
外科学   470篇
综合类   165篇
预防医学   399篇
眼科学   176篇
药学   237篇
中国医学   14篇
肿瘤学   283篇
  2023年   23篇
  2022年   43篇
  2021年   80篇
  2020年   60篇
  2019年   64篇
  2018年   79篇
  2017年   43篇
  2016年   64篇
  2015年   74篇
  2014年   125篇
  2013年   146篇
  2012年   208篇
  2011年   254篇
  2010年   142篇
  2009年   127篇
  2008年   214篇
  2007年   197篇
  2006年   142篇
  2005年   158篇
  2004年   151篇
  2003年   118篇
  2002年   94篇
  2001年   72篇
  2000年   65篇
  1999年   58篇
  1998年   24篇
  1997年   21篇
  1995年   16篇
  1992年   37篇
  1991年   33篇
  1990年   25篇
  1989年   38篇
  1988年   34篇
  1987年   29篇
  1986年   27篇
  1985年   26篇
  1984年   23篇
  1983年   19篇
  1982年   14篇
  1979年   40篇
  1978年   31篇
  1977年   18篇
  1975年   14篇
  1974年   26篇
  1973年   21篇
  1972年   16篇
  1971年   20篇
  1970年   26篇
  1969年   15篇
  1966年   17篇
排序方式: 共有3632条查询结果,搜索用时 0 毫秒
1.
Gall bladder perforation is a potentially life-threatening condition. Spontaneous perforation is infrequent and rarely seen in the absence of gallstones but gall bladder perforation is an occasional complication of typhoid fever. If such perforations are not treated in time, mortality rates are very high. We report a case of gall bladder perforation complicating typhoid fever following enteric perforation of the ileum necessitating sequential laparotomies during the same admission.  相似文献   
2.
Lymphoid clusters (LC) containing CD20-positive B cells in kidney allografts undergoing acute cellular rejection (ACR) have been identified in small studies as a prognostic factor for glucocorticoid resistance and graft loss. Allograft biopsies obtained during the first episode of ACR in 120 recipients were evaluated for LC, immunostained with CD20 antibody, and correlated with conventional histopathologic criteria, response to treatment and outcome. LC were found in 71 (59%) of the 120 biopsies. All contained CD20 positive B cells that accounted for 5-90% of the LC leukocyte content. The incidence of LC was highest in the patients who had no lymphoid depletion or had been treated with Thymoglobulin preconditioning (79% vs. 75%, respectively) compared to 37% in patients pretreated with Campath (p = 0.0001). Banff 1a/1b ACR were more frequent in the LC-positive than the LC-negative group (96% vs. 80%, respectively; p = 0.0051). With a posttransplant follow-up of 953 +/- 430 days, no significant differences were detected between LC-postitive and LC-negative groups in time to ACR, steroid resistance, serum creatinine and graft loss. CD20+LC did not portend glucocorticoid resistance or worse short to medium term outcomes. CD20+LC may represent a heterogenous collection in which there may be a small still to be fully defined unfavorable subgroup.  相似文献   
3.
A total of 168 strains of Salmonella were isolated in the Command Pathology Laboratory (WC) Delhi Cantt during the year 1990. Out of this, 143 were Salmonella typhi, 17 Salmonella paratyphi A, 7 Salmonella typhimurium and 1 Salmonella manhattan. The commonest phage type and biotype of Salmonella typhi was type E1 and type 1 respectively. The dominant biotype of Salmonella paratyphi A was type I. There was a very high degree of multidrug resistance of most of the strains. But all the strains were sensitive to ciprofloxacin and norfloxacin.  相似文献   
4.
5.
Introduction Hydatid cysts of the lung are quite frequent in our country. Some patients have additional cysts in the liver. Though most of the liver cysts remain asymptomatic for long time, but may be symptomatic with increasing size. Surgical removal is the treatment of choice for both lung & liver cysts. Aim of the study was to establish suitability of one stage surgery for pulmonary & hepatic hydatid cysts. Methods From 1996 through 2003 we operated on 216 pulmonary hydatid cysts, out of which 42 patients had hydatid cysts in the right lung as well as in the right lobe of liver. Right thoracotomy was done to remove the lung hydatids followed by phrenotomy to remove the liver cysts. Results Right thoracotomy was done in 42 patients having hydatid cysts of lung & liver. In 36 patients, cysts were removed, bronchial leaks were sutured & residual cavities were obliterated. Out of rest 6 patients, having dense adhesions or destruction of pulmonary parenchyma, 4 had segmentectomy & 2 had lobectomy. Right phrenotomy was then done with radial incision above the palpated liver cysts. Hydatid cyst was removed from liver. Cavity and remaining pericystic liver tissue was inverted with sutures. Water seal chest drain & subdiaphragmatic drain were placed. Post operative albendazole was continued for 3 months in the dose of 10–20 mg/kg with a gap of 2 weeks after each month. Post operative recovery was uneventful in most of the cases. However, air leak continued for almost 3 weeks in 4 patients & 3 months in one patient. There was no death. Conclusion Surgical management of pulmonary and hepatic hydatids with one stage right thoracotomy & phrenotomy is a suitable option. It avoids additional laparotomy and thereby additional cost & hospital stay. Results are quite satisfactory.  相似文献   
6.
7.
Poliomyelitis in India.   总被引:1,自引:0,他引:1  
R N Basu 《Indian pediatrics》1991,28(6):589-592
  相似文献   
8.
9.
Protein kinase C (PKC) has been implicated in enhancing cellular sensitivity to cis-diamminedichloroplatinum(II) (CP). We have synthesized a series of novel analogues of lyngbyatoxin A (7-linalylindolactam V), a natural tumor promoter and a potent activator of PKC, and investigated the effects of these synthetic compounds on PKC activity and the antiproliferative activity of CP. Lyngbyatoxin A was as effective as phorbol esters, such as 12-O-tetradecanoylphorbol-13-acetate, in enhancing the sensitivity of HeLa cells to CP. A 24-h pretreatment of HeLa cells with 1 to 100 nM lyngbyatoxin A caused an approximately 9-fold sensitization to CP. All analogues of lyngbyatoxin A that retained the lactam ring portion of the molecule but contained different hydrophobic substituents at C-7 including indolactam V (ILV), tert-butyl-ILV, or n-hexyl-ILV increased cellular sensitivity to CP in a concentration-dependent manner. Maximum cellular sensitization to CP (9-fold) was seen with 10 nM n-hexyl or tert-butyl compounds, and ILV devoid of any C-7 substitution required higher concentrations (1 microM) for equivalent sensitization. The ability of lyngbyatoxin A analogues to sensitize cells to CP correlated directly with their ability to activate PKC in vitro. Synthetic analogues that lacked the lactam ring structure neither activated PKC nor sensitized cells to CP. The C-9 epi analogue of n-hexyl-ILV was less effective than the corresponding natural stereoisomer in activating PKC as well as sensitizing cells to CP. Exposure of HeLa cells to 100 nM lyngbyatoxin A for 24 h caused a substantial decrease in cellular PKC activity to 20% of the untreated control value, but a similar treatment of cells with n-hexyl- or tert-butyl-ILV led to only a 25% reduction in PKC activity. Concentrations of ILV (e.g. 1 microM) that sensitized HeLa cells to CP caused no down-regulation of PKC. Thus, on the basis of results with these novel lyngbyatoxin A analogues, we conclude that activation but not down-regulation of PKC is necessary for sensitization of HeLa cells to CP.  相似文献   
10.
Chronic human health problems, namely arteriosclerosis, myocardial ischemia, and cancer, may be caused by highly active oxygen species and may be preventable by antioxidant vitamins. In humans, the sources of two major antioxidants, beta-carotene and alpha-tocopherol, are dietary. In this study, we measured the plasma concentrations of beta-carotene and alpha-tocopherol by reverse-phase high-pressure liquid chromatography in a cross-sectional sampling of 116 women. Significantly reduced plasma levels of beta-carotene and alpha-tocopherol were observed in women with histopathologically diagnosed cervical dysplasias or cancer (p less than 0.0001 and p less than 0.005, respectively). There was an inverse association between the plasma levels of both beta-carotene and alpha-tocopherol and increasingly severe graded cervical histopathology. In groups with advanced dysplasias, the percentage of smokers was markedly increased and the women were comparatively older (p less than 0.0001). A strong association was noted between smoking status and plasma beta-carotene levels, independent of cervical pathology. However, this was not evident with respect to alpha-tocopherol. The findings suggest that the antioxidants beta-carotene and alpha-tocopherol have biologic functions that are interdependent in the pathogenesis of cervical intraepithelial lesions and cervical cancer.  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