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   2843篇
  免费   143篇
  国内免费   32篇
耳鼻咽喉   24篇
儿科学   120篇
妇产科学   77篇
基础医学   362篇
口腔科学   33篇
临床医学   256篇
内科学   473篇
皮肤病学   108篇
神经病学   144篇
特种医学   129篇
外科学   346篇
综合类   161篇
预防医学   171篇
眼科学   139篇
药学   225篇
中国医学   54篇
肿瘤学   196篇
  2023年   12篇
  2021年   70篇
  2020年   29篇
  2019年   39篇
  2018年   58篇
  2017年   51篇
  2016年   77篇
  2015年   64篇
  2014年   90篇
  2013年   148篇
  2012年   173篇
  2011年   147篇
  2010年   134篇
  2009年   80篇
  2008年   122篇
  2007年   141篇
  2006年   98篇
  2005年   100篇
  2004年   109篇
  2003年   82篇
  2002年   70篇
  2001年   69篇
  2000年   80篇
  1999年   65篇
  1998年   65篇
  1997年   61篇
  1996年   49篇
  1995年   39篇
  1994年   40篇
  1993年   49篇
  1992年   28篇
  1991年   43篇
  1990年   46篇
  1989年   60篇
  1988年   42篇
  1987年   42篇
  1986年   26篇
  1985年   23篇
  1984年   22篇
  1983年   22篇
  1982年   18篇
  1981年   14篇
  1980年   15篇
  1979年   19篇
  1978年   9篇
  1977年   10篇
  1976年   13篇
  1975年   11篇
  1969年   11篇
  1941年   11篇
排序方式: 共有3018条查询结果,搜索用时 312 毫秒
1.
Vacuum-assisted closure (VAC), although a modern adjunct in wound management, has not been used previously in pyoderma gangrenosum (PG), probably to avoid the potential complications of ‘pathergy’. We would like to report our experience of VAC in three cases of PG with the relevant review of literature.  相似文献   
2.
This report describes a new PCR-based assay for the detection of Pseudomonas aeruginosa genotype D in occupational saturation diving systems in the North Sea. This genotype has persisted in these systems for 11 years (1993-2003) and represents 18% of isolates from infections analysed during this period. The new PCR assay was based on sequences obtained after randomly amplified polymorphic DNA (RAPD)-PCR analysis of a group of isolates related to diving that had been identified previously by pulsed-field gel electrophoresis (PFGE). The primer set for the D genotype targets a gene that codes for a hypothetical class 4 protein in the P. aeruginosa PAO1 genome. A primer set able to detect P. aeruginosa at the species level was also designed, based on the 23S-5S rDNA spacer region. The two assays produced 382-bp and 192-bp amplicons, respectively. The PCR assay was evaluated by analysing 100 P. aeruginosa isolates related to diving, representing 28 PFGE genotypes, and 38 clinical and community P. aeruginosa isolates and strains from other species. The assay identified all of the genotype D isolates tested. Two additional diving-relevant genotypes (TP2 and TP27) were also identified, as well as three isolates of non-diving origin. It was concluded that the new PCR assay is a useful tool for early detection and prevention of infections with the D genotype.  相似文献   
3.
4.
5.
6.
Background. Extensive questioning of patients with a wide variety of skin disorders led to the impression that nocturnal overheating was probably an important factor in the initiation and the perpetuation of many skin disorders. Methods. In order to test the hypothesis, 12 “clean-skinned” subjects (6M/6F) aged 18 to 45 years were monitored electronically every 30 seconds during an 8 hour sleep period (2300 to 0700 hours), sleeping under a standard 10 tog duvet. Results. All the subjects were too hot by 3 to 4°C. All showed changes in their EEG patterns with reduced REM sleep, increased awakenings, and all showed changes in their sleep stage patterns. In addition, they all showed evidence of increased sweating in the “heat-sink” area. Conclusions. The mechanisms where by such changes could be implicated in the precipitation and perpetuation of skin disease are discussed. “Lifestyle” modification as a very effective, noninvasive, therapeutic regime is recommended. Further research along these lines would probably be very valuable and instructive.  相似文献   
7.
A gradual reduction in cell-mediated immunity is thought to occur with the progression of human immunodeficiency virus (HIV) infection. This suggests a selective attrition of the Th1 subset. The regulation of the soluble form of the low-affinity receptor for IgE (sCD23) by the opposing actions of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) allows the assessment of the overall balance of Th1 to Th2 activity in a given disease. In order to investigate this further we employed an enhanced chemiluminescent ELISA to analyse serum levels of sCD23 in male subjects with and without HIV infection. Serum levels of sCD23 were similar in 34 HIV seronegative homosexuals, 39 homosexuals with asymptomatic HIV infection, 27 homosexuals with acquired immune deficiency syndrome (AIDS) and 20 healthy controls. This suggests that HIV has no predilection for either the Th1 or Th2 subsets of CD4 T cells.  相似文献   
8.
9.
10.
Ten thrombocytopenic patients (platelets < 10–24 × 10(9)/L) who were refractory to platelet transfusion were investigated for their responsiveness to staphylococcal protein A column therapy. Nine patients had previously been treated with steroids, intravenous immune globulin, and/or other forms of immunosuppressive therapy without improvement in their transfusion response. All patients were receiving multiple platelet transfusions without achieving 1-hour corrected count increments (CCIs) > or = 7500. Eight patients had antibodies that reacted with platelets and were directed against HLA class I antigens, ABO antigens, and/or platelet-specific alloantigens. Plasma (500-2000 mL) from each patient was passed over a protein A silica gel column and then returned to the patient. Patients received from 1 to 14 treatments. A positive response to protein A therapy was defined as at least a doubling of the pretreatment platelet count and/or two successive 10- to 120-minute posttransfusion CCIs > or = 7500. Following plasma treatments, 6 of 10 patients responded with daily platelet counts that averaged 48 +/− 11 × 10(9) per L as compared with counts of 16 +/− 7 × 10(9) per L (p < 0.0005) before treatment. Posttransfusion CCI values determined in four of these patients averaged 2480 +/− 810 and 10,010 +/− 3540 (p < 0.005) before and after treatment, respectively. In contrast, among the four unresponsive patients, platelet counts averaged 10 +/− 9 and 13 +/− 10 × 10(9) per L (p = NS), respectively, while posttransfusion CCIs were 700 +/− 1410 and 1520 +/− 2460 (p = NS), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  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