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   903289篇
  免费   62603篇
  国内免费   2339篇
耳鼻咽喉   12507篇
儿科学   28781篇
妇产科学   26213篇
基础医学   127096篇
口腔科学   24849篇
临床医学   75154篇
内科学   183733篇
皮肤病学   19049篇
神经病学   71602篇
特种医学   36545篇
外国民族医学   336篇
外科学   142609篇
综合类   19108篇
一般理论   250篇
预防医学   64907篇
眼科学   20108篇
药学   64019篇
中国医学   1800篇
肿瘤学   49565篇
  2018年   9118篇
  2017年   7216篇
  2016年   7711篇
  2015年   8772篇
  2014年   12448篇
  2013年   19342篇
  2012年   25816篇
  2011年   27407篇
  2010年   16658篇
  2009年   15850篇
  2008年   26268篇
  2007年   27872篇
  2006年   28066篇
  2005年   27583篇
  2004年   26425篇
  2003年   25577篇
  2002年   25176篇
  2001年   41463篇
  2000年   42660篇
  1999年   36375篇
  1998年   10019篇
  1997年   9198篇
  1996年   9119篇
  1995年   8485篇
  1994年   8117篇
  1993年   7625篇
  1992年   28271篇
  1991年   27068篇
  1990年   26494篇
  1989年   25421篇
  1988年   23628篇
  1987年   23228篇
  1986年   22321篇
  1985年   21211篇
  1984年   15854篇
  1983年   13517篇
  1982年   8110篇
  1979年   14635篇
  1978年   10236篇
  1977年   8643篇
  1976年   8177篇
  1975年   8984篇
  1974年   10723篇
  1973年   10229篇
  1972年   9693篇
  1971年   8955篇
  1970年   8610篇
  1969年   8057篇
  1968年   7708篇
  1967年   7119篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Streptococcus agalactiae, known as a pathogen that causes meningitis and septicemia in neonates, emerges as an invasive organism in nonpregnant adults. This case report describes the fulminant course of a necrotizing fasciitis (NF) with streptococcal toxic shock-like syndrome (STSS) in a 76-year-old diabetic patient caused by S. agalactiae, serotype V. Chronic diseases and immunodeficiency are considered to be risk factors for the acquisition of group B streptococcal disease. Since early surgical treatment in conjunction with antimicrobial and intensive care therapy is critical for the outcome of patients with NF and/or STSS, clinicians should be aware of invasive S. agalactiae infections in adults with subcutaneous emphysema.  相似文献   
992.
We tested the hypothesis that bone mineral density (BMD) and bone mineral content (BMC) in proximal human femur specimens in the upper neck region of interest (ROI) and femoral neck axis length (FNAL) provide a significantly better prediction of femoral bone strength than standard ROIs in vitro. BMD and BMC were measured in 110 proximal femur specimens using a standard dual-energy X-ray absorptiometry (DXA) scanner. The analysis included a new ROI in the upper neck as well as the standard ROIs. FNAL was obtained from the scan images. The specimens' failure-load was measured in a mechanical loading device, simulating a fall on the greater trochanter. For the standard ROIs, correlations between failure-load and BMD ranged from R2 = 0.64 (shaft ROI) to R2 = 0.70, p < 0.001 (femoral neck). Prediction of strength by BMD did not significantly differ from those of BMC (R2 ranging from 0.65 to 0.75, p < 0.001). In the upper neck ROI, for both BMD and BMC correlations with failure-load were higher (R2 = 0.76 and 0.81, respectively; p < 0.001). A lower, yet still significant, correlation was found between FNAL and bone strength (R2 = 0.23, p < 0.001). Normalization of failure-load with respect to FNAL did not significantly increase the correlations with densitometric measures. This study provides in vitro evidence indicating that among the ROIs of the proximal femur the newly defined upper neck ROI provides the best prediction of bone strength. Only a weak association was observed between failure load and FNAL.  相似文献   
993.
994.
BACKGROUND AND AIMS: Liver surgery is developing with new techniques and treatment modalities. The aim of this study is to describe liver surgery over a long period of time in a country with a public health care system. PATIENTS AND METHOD: A register study including adult patients admitted for liver resection in Sweden (population 8.8 million) selected from the Inpatient Register 1987-99. Additional data were collected from the Swedish Cancer Register and the Cause of Death Register. Analyses of the patients, indications, mortality and causes of death are presented. RESULTS: 2,405 operations were performed (21 per million per year). The most frequent indication was colorectal metastases (27%). The 5-year survival after an operation for primary liver cancer and colorectal liver metastases was 27% and 26%, respectively. CONCLUSIONS: Few patients were admitted for liver operations compared to expected figures. The survival rates are in conformity with those previously published. With an increasing awareness of the relatively favourable prognosis and the introduction of new methods, the volume of liver operations will probably increase in Sweden.  相似文献   
995.
The prevalence of bad self-rated health (SRH) varies considerably across countries. Here we present the results of a cross-national comparative study based on the data of National Health Surveys conducted in France and Italy. According to these data, 11% of the Italian and 6% of the French adult population aged between 45 and 74 rate their health as bad or very bad. This gap may result from differences in population structure regarding the individual characteristics (sociodemographic characteristics, diseases and disabilities, lifestyle, and others) that impact on SRH i.e., a structural effect. It may also be that the link between these characteristics and SRH is “country-specific” i.e., a contextual effect. We use logistic regression models to assess the contribution of both explanations. We find that the structural effect plays a prominent role in the higher prevalence of bad SRH in Italy compared to France.  相似文献   
996.
997.
998.
999.
1000.
Ultrasensitive bright field in situ hybridization assays using enzyme metallography (EnzMet) have been developed and validated, but little is known regarding the applicability of EnzMet for immunophenotypic detection of protein via IHC. Superior resolution via discrete metallographic deposits offers the potential for enhancing high-resolution immunophenotyping. Using high-complexity tissue microarrays (TMAs), 88 common solid tumors were evaluated by automated EnzMet (Nanoprobes and Ventana). Targets were chosen to assess the ability of EnzMet to specifically localize encoded antigens in the nucleus (estrogen receptor), cytoplasm (cytokeratins), and cytoplasmic membrane (HER2) in TMAs. Results were compared with conventional IHC diaminobenzidine (DAB) immunostaining. There was full concordance between the EnzMet and conventional IHC results. Furthermore, the EnzMet reaction products did not appreciably diffuse, were dense and sharply defined, and provided excellent high-resolution differentiation of cellular compartments in paraffin sections for the nuclear, cytoplasmic, and cell membrane-localized antigens evaluated. The higher density of elemental silver deposited during enzyme metallography permitted evaluation of core immunophenotypes at a relatively low magnification, allowing more tissue to be screened in an efficient manner. This preliminary study shows the utility of using enzyme metallography for high-resolution immunophenotyping in TMAs.  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