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   1246篇
  免费   125篇
  国内免费   13篇
耳鼻咽喉   2篇
儿科学   50篇
妇产科学   13篇
基础医学   164篇
口腔科学   25篇
临床医学   151篇
内科学   229篇
皮肤病学   21篇
神经病学   105篇
特种医学   196篇
外科学   112篇
综合类   53篇
一般理论   2篇
预防医学   117篇
眼科学   10篇
药学   68篇
  1篇
中国医学   1篇
肿瘤学   64篇
  2022年   5篇
  2021年   12篇
  2020年   7篇
  2019年   12篇
  2018年   17篇
  2017年   13篇
  2016年   11篇
  2015年   14篇
  2014年   17篇
  2013年   30篇
  2012年   45篇
  2011年   61篇
  2010年   40篇
  2009年   32篇
  2008年   49篇
  2007年   64篇
  2006年   49篇
  2005年   51篇
  2004年   41篇
  2003年   52篇
  2002年   37篇
  2001年   47篇
  2000年   38篇
  1999年   26篇
  1998年   38篇
  1997年   33篇
  1996年   24篇
  1995年   33篇
  1994年   26篇
  1993年   44篇
  1992年   25篇
  1991年   19篇
  1990年   21篇
  1989年   33篇
  1988年   35篇
  1987年   47篇
  1986年   34篇
  1985年   35篇
  1984年   19篇
  1983年   19篇
  1982年   11篇
  1981年   17篇
  1980年   21篇
  1979年   10篇
  1978年   13篇
  1977年   9篇
  1976年   4篇
  1975年   7篇
  1973年   3篇
  1969年   4篇
排序方式: 共有1384条查询结果,搜索用时 0 毫秒
101.
Autopsy reports accumulated since 1991 contained 30 cases in which routine radiological investigation had demonstrated radio-dense stippling of the epiphyses. The case histories, pregnancy progress, clinical manifestations, cytogenetic investigations, and autopsy findings have been tabulated and analysed for the purpose of diagnostic discrimination. Firm diagnoses were obtained in eight instances: warfarin embryopathy—three, trisomy 18—three, lethal multiple pterygium syndrome—one. Other possible but unconfirmed diagnoses were chromosomal aneuploidy—three, sonic hedgehog phenotype—one, CHARGE association—one, intrauterine infection—one. The value of autopsy in foetuses and neonates with lethal epiphyseal stippling syndromes is exemplified by the detection of multiple visceral abnormalities in ten instances.  相似文献   
102.
103.
104.
Psoriasis is associated with significant physical and psychological burden affecting all facets of a patient’s life – relationships, social activities, work and emotional wellbeing. The cumulative effect of this disability may be self‐perpetuating social disconnection and failure to achieve a ‘full life potential’ in some patients. Health‐related quality of life studies have quantified the burden of psoriasis providing predominantly cross‐sectional data and point‐in‐time images of patients’ lives rather than assessing the possible cumulative disability over a patient’s lifetime. However, social and economic outcomes indicate there are likely negative impacts that accumulate over time. To capture the cumulative effect of psoriasis and its associated co‐morbidities and stigma over a patient’s life course, we propose the concept of ‘Cumulative Life Course Impairment’ (CLCI). CLCI results from an interaction between (A) the burden of stigmatization, and physical and psychological co‐morbidities and (B) coping strategies and external factors. Several key aspects of the CLCI concept are supported by data similar to that used in health‐related quality of life assessments. Future research should focus on (i) establishing key components of CLCI and determining the mechanisms of impairment through longitudinal or retrospective case–control studies, and (ii) assessing factors that put patients at increased risk of developing CLCI. In the future, this concept may lead to a better understanding of the overall impact of psoriasis, help identify more vulnerable patients, and facilitate more appropriate treatment decisions or earlier referrals. To our knowledge, this is a first attempt to apply and develop concepts from ‘Life Course Epidemiology’ to psoriasis research.  相似文献   
105.
106.
107.
Patterns of muscle activity (motor patterns) have generally been found to be strongly conserved during the evolution of aquatic feeding behavior within closely related groups of fishes and salamanders. We conducted a test of the generality of motor pattern conservation with a much broader phylogenetic scope than has been done previously. Activity patterns of three cranial muscles were quantified from electromyographic (EMG) recordings made during suction feeding in a salamander (Ambystoma mexicanum) and 4 widely divergent species of ray-finned fishes (Amia calva, Notopterus chitala, Micropterus salmoides and Lepomis macrochirus). General features of the motor pattern were the same in all species, but multivariate and univariate analyses of variance revealed highly significant differences among the 5 species in the average muscle activity pattern, indicating that the motor pattern has not been precisely conserved among these 5 taxa. Five of eight EMG variables that describe the intensity and timing of muscle activity differed among species. Only the intensity of activity of the adductor mandibulae appears to be a strongly conserved feature of the suction feeding motor pattern in anamniotes. A discriminant function analysis of the 8 EMG variables successfully classified about two thirds of the feeding incidents as belonging to the correct species. In contrast to the results of previous studies of closely related taxa, we found that numerous quantitative differences exist among species, indicating that functionally significant details of suction feeding motor patterns have changed during evolution, whereas several general features of the pattern have been conserved.  相似文献   
108.
The most accurate prognostic indicator in patients with musculoskeletal sarcomas is the percentage of tumor necrosis after intraarterial chemotherapy. Magnetic resonance (MR) imaging was evaluated to determine its ability to indicate the percentage of necrosis in musculoskeletal neoplasms after treatment. Fourteen patients with musculoskeletal neoplasms underwent treatment protocols including intraarterial chemotherapy (n = 14), radiation therapy (n = 6), and systemic chemotherapy (n = 14). All patients underwent MR imaging before and after treatment, and all underwent either limb salvage surgery (n = 8) or amputation (n = 6) within 1 week of the last MR examination. Standard unehanced spin-echo T1-, spin-density-, and T2-weighted MR sequences were used. The MR images were compared with the pathologic specimens. On T2-weighted images, the signal intensities of viable tumor, tumor necrosis, edema, hemorrhage, and necrosis overlapped. With the unenhanced spin-echo technique, MR imaging cannot be used to predict the percentage of tumor necrosis in musculoskeletal neoplasms after intraarterial chemotherapy.  相似文献   
109.
110.
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