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   22897篇
  免费   2239篇
  国内免费   514篇
耳鼻咽喉   68篇
儿科学   1998篇
妇产科学   308篇
基础医学   2366篇
口腔科学   208篇
临床医学   1655篇
内科学   4350篇
皮肤病学   199篇
神经病学   1248篇
特种医学   666篇
外国民族医学   1篇
外科学   1224篇
综合类   3162篇
现状与发展   3篇
预防医学   2494篇
眼科学   309篇
药学   1197篇
  12篇
中国医学   3814篇
肿瘤学   368篇
  2024年   115篇
  2023年   410篇
  2022年   977篇
  2021年   1282篇
  2020年   1070篇
  2019年   812篇
  2018年   772篇
  2017年   962篇
  2016年   936篇
  2015年   879篇
  2014年   1477篇
  2013年   1617篇
  2012年   1205篇
  2011年   1318篇
  2010年   982篇
  2009年   900篇
  2008年   829篇
  2007年   880篇
  2006年   811篇
  2005年   667篇
  2004年   615篇
  2003年   555篇
  2002年   478篇
  2001年   427篇
  2000年   367篇
  1999年   325篇
  1998年   335篇
  1997年   268篇
  1996年   272篇
  1995年   274篇
  1994年   241篇
  1993年   222篇
  1992年   200篇
  1991年   206篇
  1990年   185篇
  1989年   184篇
  1988年   178篇
  1987年   147篇
  1986年   151篇
  1985年   187篇
  1984年   137篇
  1983年   88篇
  1982年   130篇
  1981年   112篇
  1980年   80篇
  1979年   97篇
  1978年   57篇
  1977年   51篇
  1976年   54篇
  1975年   40篇
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
71.
72.
Hip arthroplasty is a common orthopaedic procedure with proven long-term success and reliable results. A wide range of associated conditions may affect the outcome of the arthroplasty and the surgeon has to keep these in mind when planning the surgery. In this article, such situations are discussed and recommendations are drawn from the evidence available in literature.  相似文献   
73.
Background. Transferrin binds extracellular iron and protectstissues from iron-induced oxidative stress. The binding of ironand transferrin is pH dependent and conventional peritonealdialysis (PD) solutions have unphysiologically low pH values.Herein, we investigated whether conventional PD solution releasesiron from transferrin and if the released iron causes oxidativestress. Methods. Effects of PD solutions on iron binding to transferrinwere examined with purified human transferrin and transferrinin dialysates drained from PD patients. Oxidative stress inducedby iron released from transferrin was evaluated in terms ofthe formation of thiobarbituric acid reactive substance (TBARS)and protein carbonylation in the human red blood cell (RBC)membrane. The iron deposition in peritoneal tissue from PD patientswas evaluated by Perls' staining with diaminobenzidine intensification. Results. Low pH PD solution released iron from transferrin.This iron release occurred within 1 min. Iron release was notobserved in neutralized PD solution. Iron released from transferrinin low pH PD solution increased TBARS formation and proteincarbonylation in the human RBC membrane. Iron deposition, whichis prominent in the fibrotic area facing the peritoneal cavity,was observed in the peritoneum of PD patients. Conclusions. Iron released from transferrin in low pH PD solutioncan produce oxidative stress in the peritoneum of a PD patient.Neutralizing PD solution can avoid this problem. Iron depositionin the peritoneum may participate in the pathogenesis of peritonealfibrosis in PD patients.  相似文献   
74.
六味地黄冲剂对肾阴虚病人血浆中锌铜含量的影响   总被引:1,自引:0,他引:1  
肾阴虚病人血浆中锌、铜含量均较正常人血浆中锌,铜含量明显增高(P<0.01)。男女性别间本组未见差异。服用治疗肾阴虚药物六味地黄3种剂型后均使锌,铜含量明显降低(P<0.01),六味地黄冲剂与汤剂效果一致。  相似文献   
75.
76.
Melanoses of the gastrointestinal tract   总被引:4,自引:0,他引:4  
Electronmicroscopy and electron probe energy dispersive X-ray analysis studies have substantially contributed to our understanding of the various gastrointestinal tract melanoses. The nature of the pigment granules which occur in the various melanoses is discussed; their pattern of distribution in melanosis coli, melanosis ilei, melanosis duodeni and melanosis oesophagi is summarized and current knowledge of the aetiology and pathogenesis of these conditions is reviewed. Brief mention is also made of other examples of lipofuscin pigmentation, and a case of haemosiderosis ilei is described.  相似文献   
77.
A rare case of factor XI (PTA) deficiency was discovered in a Saudi family in the Riyadh area. Nine members of the family were studied. Two were found to have a severe PTA deficiency’ levels of factor XI clotting activity were 0.01 i.u./ml and 0.02 i.u./ml respectively. Both plasmas were markedly deficient in factor XI antigen and appeared to be negative for cross-reactive material (CRM-). The parents were first cousins and both were found to have a minor PTA deficiency. Factor XI levels were: mother 0.048 i.u./ml and father 0.33 i.u./ml. Another sibling was found to have a FXI level of 0.47 i.u./ml. Menorrhagia and bleeding for 1 day after tooth extraction were the main bleeding manifestations found in one member with severe PTA deficiency. Clinically this member presented with iron deficiency anaemia. Other family members had no significant history of bleeding tendency. This is the first report of a Saudi Arabian family with PTA deficiency.  相似文献   
78.
用免疫组织化学PAP法显示实验性脾虚组和正常对照组大鼠胰岛B细胞(胰岛素细胞)、A细胞(胰高血糖素细胞)和D细胞(生长抑素细胞).结果显示,实验组胰岛素分泌升高(P<0.01),胰高血糖素和生长抑素分泌下降(P<0.05)。实验结果提示大鼠胰岛A、B和D细胞分泌活动的变化与脾虚证的症候可能有密切关系。  相似文献   
79.
The purpose of this study was to evaluate the outcome of tension-free vaginal tape (TVT) procedure in women with urodynamic stress incontinence diagnosed as having intrinsic sphincteric deficiency (ISD). The combination of a maximal urethral closure pressure <20 cm H2O and a Valsalva leak point pressure <60 cm H2O was considered as diagnostic of ISD. Subjects with detrusor overactivity on preoperative urodynamics were excluded. A total of 35 patients with both low closure pressure and leak point pressure were enrolled. Bladder perforation occurred in three (8.6%) cases. Postoperative urinary voiding difficulties occurred in nine (25.7%) women. Two patients underwent surgical detension of the tape, with complete resolution of urinary retention and no relapse of incontinence. Women with postoperative voiding dysfunction had a significantly lower detrusorial pressure at the peak flow on preoperative urodynamics compared to those who voided efficiently after TVT. The mean (range) follow-up time was 12.5 months (3–36). The objective cure rate for stress incontinence was 91.4%. Two of the three (66%) patients in whom the TVT procedure failed had a fixed urethra. De novo urge incontinence was found in five (14.3%) patients.  相似文献   
80.
Metastasis (the spread of cancer from a primary tumor to secondary organs) is responsible for most cancer deaths. The ability to follow the fate of a population of tumor cells over time in an experimental animal would provide a powerful new way to monitor the metastatic process. Here we describe a magnetic resonance imaging (MRI) technique that permits the tracking of breast cancer cells in a mouse model of brain metastasis at the single-cell level. Cancer cells that were injected into the left ventricle of the mouse heart and then delivered to the brain were detectable on MR images. This allowed the visualization of the initial delivery and distribution of cells, as well as the growth of tumors from a subset of these cells within the whole intact brain volume. The ability to follow the metastatic process from the single-cell stage through metastatic growth, and to quantify and monitor the presence of solitary undivided cells will facilitate progress in understanding the mechanisms of brain metastasis and tumor dormancy, and the development of therapeutics to treat this disease.  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