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   2599057篇
  免费   201188篇
  国内免费   6346篇
耳鼻咽喉   34870篇
儿科学   86175篇
妇产科学   73006篇
基础医学   375140篇
口腔科学   74916篇
临床医学   241423篇
内科学   500057篇
皮肤病学   54237篇
神经病学   213454篇
特种医学   99192篇
外国民族医学   804篇
外科学   378121篇
综合类   62360篇
现状与发展   4篇
一般理论   958篇
预防医学   212749篇
眼科学   59023篇
药学   194529篇
  9篇
中国医学   5428篇
肿瘤学   140136篇
  2018年   27418篇
  2017年   21036篇
  2016年   23195篇
  2015年   26655篇
  2014年   36749篇
  2013年   56750篇
  2012年   77224篇
  2011年   81873篇
  2010年   48043篇
  2009年   45078篇
  2008年   76577篇
  2007年   80859篇
  2006年   81494篇
  2005年   79105篇
  2004年   76703篇
  2003年   73180篇
  2002年   71531篇
  2001年   116992篇
  2000年   120890篇
  1999年   102053篇
  1998年   28853篇
  1997年   26231篇
  1996年   25960篇
  1995年   25084篇
  1994年   23566篇
  1993年   22260篇
  1992年   83416篇
  1991年   81621篇
  1990年   79445篇
  1989年   76293篇
  1988年   70973篇
  1987年   69643篇
  1986年   66415篇
  1985年   63954篇
  1984年   48092篇
  1983年   41302篇
  1982年   24693篇
  1981年   21985篇
  1979年   45121篇
  1978年   31714篇
  1977年   26535篇
  1976年   25346篇
  1975年   26569篇
  1974年   32468篇
  1973年   31439篇
  1972年   28938篇
  1971年   27170篇
  1970年   25043篇
  1969年   23257篇
  1968年   21754篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Erythropoietin exerts hematopoietic effects by stimulating proliferation of early erythroid precursors. Nonhematopoietic effects of erythropoietin have also been shown. It may act as a new angiogenic factor in wound healing. This study aimed to investigate the effect of systemic administration of recombinant human erythropoietin on wound healing in mice. Dorsal incisional wounds were performed in mice, which were then divided into two groups; a group treated for 7 days with recombinant human erythropoietin, and a control group. Sacrificing animals on day 7, the wound tissues were collected for analysis of wound breaking strength, malondialdehyde, a marker of lipid peroxidation, hydroxyproline, an index of reparative collagen deposition, reduced glutathione levels, and for histological evaluation. The immunohistochemical determination of vascular endothelial growth factor (VEGF) which is believed to be the most prevalent angiogenic factor throughout the skin repair process, was also studied. The treatment significantly increased wound breaking strength by decreasing malondialdehyde and increasing hydroxyproline levels on day 7 after wounding. No statistically meaningful change was observed in reduced glutathione content. VEGF was immunostained significantly more on wound tissue of treated animals compared to the control group. Recombinant human erythropoietin treatment may be effective in wound healing due to inhibition of lipid peroxidation, deposition of collagen, and VEGF expression in wound area.  相似文献   
102.
103.
104.
105.
Molecular characterization of Wuchereria bancrofti is essential to develop suitable anti-filarial drugs and vaccines. We describe here isolation, sequence analysis and cloning of a partial cDNA of an enzyme superoxide dismutase from this parasite. The immunoscreening of a lambda zap W. bancrofti microfilarial (Mf) cDNA library with microfilaremic sera had resulted in the isolation of several seroreactive clones including, WbSOD. This clone contained a 309 bp insert and showed significant nucleotide and deduced amino acid sequence homologies to the superoxide dismutases of other nematode parasites. The antioxidant property of this enzyme may have important contribution in the defense mechanism of the parasite against host immune response.  相似文献   
106.
The authors discuss techniques for Monte Carlo (MC) cohort simulations that reduce the number of simulation replications required to achieve a given degree of precision for various output measures. Known as variance reduction techniques, they are often used in industrial engineering and operations research models, but they are seldom used in medical models. However, most MC cohort simulations are well suited to the implementation of these techniques. The authors discuss the cost of implementation versus the benefit of reduced replications.  相似文献   
107.
Consecutive patients (n = 215) who were referred to optometric (55%) or multidisciplinary (45%) low-vision services and above 50 years of age were recruited from four hospitals in the Netherlands. They completed two vision-related quality of life questionnaires, the Vision Quality of Life Core Measure (VCM1) and the Low Vision Quality of Life Questionnaire (LVQOL), before their first visit with low-vision services and 1 year later. At follow-up, patients referred to multidisciplinary low-vision services had lower scores on the mobility subscale of the LVQOL than patients referred to optometric low-vision services [5.3 points; 95% confidence interval (CI): 0.2-10.5]. Paired sample t-tests for the two groups of patients taken together show improvement for the VCM1 (3.1 points; 95% CI: 0.6-5.6) and deterioration for the basic aspects of vision (3.5 points; 95% CI: 1.1-5.9) and the mobility (6.6 points; 95% CI: 3.7-9.5) subscales of the LVQOL. In conclusion, people referred to optometric services showed less deterioration in mobility than those referred to multidisciplinary services. No differences were observed for any of the other subscales of the LVQOL and the VCM1. Future research in this field should include randomized controlled designs comparing low-vision services with no treatment or placebo.  相似文献   
108.
French asthma patients may be supervised by general practitioners (GPs) and/or specialists. Therefore, this study examined asthma management in patients exclusively supervised by specialists (SPE), GPs, (GP) and both (GP+SPE group), and compared the findings. Asthma patients were consecutively recruited in 348 pharmacies. Each patient completed a questionnaire providing data on personal characteristics, asthma management, perception of disease and asthma supervision. Asthma control was measured using the Asthma Control Test. Questionnaires were linked to computerised records of medications which had been dispensed before inclusion in the study. From the 1,256 patients (mean age = 36.1 yrs, 54.3% females), 11.4, 36.6, and 52.0% were placed in the SPE, GP, and GP+SPE groups, respectively. During the previous 4 weeks, most patients in the SPE group were properly controlled (52.2 versus 26.4 and 21.5% in GP and GP+SPE groups, respectively). The SPE group made more use of fixed combinations of long-acting beta agonist and inhaled corticosteroid, while receiving less short-acting beta agonists, antitussives and antibiotics. Striking differences in symptoms and asthma management were observed according to the type of asthma supervision. The current results strongly support the need to improve the management of asthma in primary care, and the coordination of care between general practitioners and specialists.  相似文献   
109.
110.
Research coordinators in intensive care are a growing specialty about which little is known. This cross-sectional study surveyed the Australia and New Zealand Intensive Care Research Coordinators' Group (n = 49) regarding demographics, education, employment history, job structure, and role content. Most research coordinators were highly qualified and experienced nurses who undertake pharmaceutical trials, multicenter projects, departmental medical and nursing research, audits and data registries, and their own projects.  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