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   1576400篇
  免费   127242篇
  国内免费   8614篇
耳鼻咽喉   22452篇
儿科学   49972篇
妇产科学   40114篇
基础医学   196884篇
口腔科学   39170篇
临床医学   153895篇
内科学   337121篇
皮肤病学   39861篇
神经病学   132667篇
特种医学   64245篇
外国民族医学   277篇
外科学   259940篇
综合类   32711篇
现状与发展   74篇
一般理论   538篇
预防医学   120019篇
眼科学   32978篇
药学   100578篇
  42篇
中国医学   2332篇
肿瘤学   86386篇
  2021年   13376篇
  2019年   13098篇
  2018年   22056篇
  2017年   18670篇
  2016年   21841篇
  2015年   23630篇
  2014年   36685篇
  2013年   47602篇
  2012年   47306篇
  2011年   50322篇
  2010年   37430篇
  2009年   40038篇
  2008年   47335篇
  2007年   48580篇
  2006年   51700篇
  2005年   47503篇
  2004年   44973篇
  2003年   42586篇
  2002年   40428篇
  2001年   70098篇
  2000年   71018篇
  1999年   60149篇
  1998年   20917篇
  1997年   18768篇
  1996年   19526篇
  1995年   19534篇
  1994年   17240篇
  1993年   15964篇
  1992年   48587篇
  1991年   47285篇
  1990年   45143篇
  1989年   43084篇
  1988年   39867篇
  1987年   39060篇
  1986年   36803篇
  1985年   35469篇
  1984年   27073篇
  1983年   22772篇
  1982年   14569篇
  1981年   13030篇
  1980年   12221篇
  1979年   23897篇
  1978年   17475篇
  1977年   14824篇
  1976年   13460篇
  1975年   14035篇
  1974年   16332篇
  1973年   15648篇
  1972年   14482篇
  1971年   13245篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Hirschsprung disease (HSCR) is considered a model for a complex inheritance disorder. Several genes, including the major HSCR-susceptibility RET proto-oncogene, play an aetiological role in the development of HSCR. Genetic linkage analysis in familial HSCR with both long- and short-segment phenotypes has demonstrated a tight linkage to the RET locus, while the phenotype within a HSCR family is characterised by an incomplete penetrance or a variable extension of the aganglionosis. Therefore, additional genetic alterations of RET are postulated in the aetiology or modification of the HSCR phenotype. In this study, the coding region of all 21 exons of the RET proto-oncogene, including the flanking intronic sequences, were investigated by direct DNA sequencing in a HSCR population. We genotyped the c.135 G/A polymorphism and resolved haplotypes comprising the mutation locus and the c.135 G/A polymorphism. Twenty different mutations were detected in 18 of 76 HSCR patients. In ten families the mutations were inherited from the parents, while only four patients had a positive family history for the disease. Moreover, in all ten families an incomplete penetrance of the HSCR phenotype was observed. We have investigated the effect of the non-mutated wild-type allele as well as the c.135 G/A polymorphism on the phenotype within the HSCR families. Our findings support the notion that both RET alleles are involved in the pathogenesis of a subgroup of HSCR patients in a dose-dependent fashion. Additionally, we have shown a modifying effect of the c.135 G/A polymorphism on the HSCR phenotype within HSCR families.  相似文献   
993.
994.
995.
Mindestmengen     
BACKGROUND: Consequences of the volume outcome relationship are controversial. Objectification based on data analysis is strongly needed. The aim of this publication was to analyse the effects of volume outcome reallocations based on German inpatient data. METHOD: The analysis based on inpatient data of the Krankenhauszweckverband Koeln, Bonn und Region (Hospital Association of the Cologne and Bonn Region) of 2002 and 2005. Relevant data sets were identified according to the effects of current German regulations on volume outcome on the special fields liver transplant, kidney transplant, complex pancreatic surgery, and complex oesophageal surgery. RESULTS: The effects of current German regulations on volume outcome results differed greatly between the four surgical specialities. There were fewer effects on kidney transplant, but due to an already very high level of centralisation 34% (oesophagus) and 8% (pancreas) of the hospitals stopped related surgery. This affected 8.9% (oesophagus) and 2.2% (pancreas) of related cases. CONCLUSION: Concentration and the formation of specialised medical centres are results of the implementation of volume outcome relationships. The quality of medical treatment does not automatically improve from this development. It is necessary to analyse any correlation between quality and frequency of treatment or other criteria such as know-how, structure and process management, and multidisciplinarity.  相似文献   
996.
Primary endovascular intervention is increasingly the first choice of treatment for cerebral aneurysms, particularly for those with complex anatomy in the posterior circulation. However, their clinical management and follow-up continue to be predominantly in the hands of neurosurgeons. In this report, the development of alopecia following the coiling of posterior circulation aneurysms is described. The alopecia was transient and lasted for approximately 6 months, and occurred in the occipital and suboccipital regions of the scalp. This report aims to highlight this condition, which has not been previously reported in the neurosurgical literature. The potential hazards of irradiation should be borne in mind while carrying out complex endovascular procedures. The patient should be counselled and all necessary steps undertaken to limit radiation exposure.  相似文献   
997.
998.
Clinical outcomes data can be used to facilitate patient management decisions, assess clinician and organizational performance, and to provide evidence for the effectiveness of surgery and rehabilitation. The validity of the inferences made from outcomes data are dependent on the validity of the outcomes measures themselves and the circumstances under which the data were collected, analyzed, and interpreted. Clinical outcomes may include measures of impairment of body structure and function, activity limitation, and participation restriction. However, because the relationship between impairment and the resulting activity limitation and participation restriction is not direct, and because activity limitations and participation restrictions are of the utmost concern to the athlete, the primary clinical outcome should be measures of activity limitation and participation restriction. Activity limitation and participation restriction may be measured either through direct observation of performance or by general or specific measures of health related quality of life. Clinical outcomes data must be collected systematically to ensure valid inferences from the data.  相似文献   
999.
Background. Modern medicine is rooted in ethnobotanical traditions using indigenous flora to treat symptoms of human diseases or to improve specific aspects of the body condition. Herbal medicine is now used by over half of the American population. Yet the American medical community generally lacks knowledge of the function, metabolism, interaction, adverse reactions, and preparation of herbal products.
Objective. Because over 60 botanicals are marketed in cosmeceutical formulations, dermatologists need to obtain working knowledge of the major botanicals. The preparation, traditional uses, mechanisms of action, human clinical data, adverse reactions, and interactions all impact herbal efficacy and are discussed below.
Method. English-language medical journal and symposium searches.
Results. The most important botanicals pertaining to dermatologic uses, such as cosmeceuticals, include teas, soy, pomegranate, date, grape seed, Pycnogenol, horse chestnut, German chamomile, curcumin, comfrey, allantoin, and aloe. All are documented to treat dermatologic conditions. Only green and black tea, soy, pomegranate, and date have published clinical trials for the treatment of parameters of extrinsic aging.
Conclusions. Preparation of botanical-based cosmeceuticals is complex. Very few of these products are supported by evidence-based science.
CARL THORNFELDT, MD, FAAD, HAS INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS.  相似文献   
1000.
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