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   21036篇
  免费   5951篇
  国内免费   131篇
耳鼻咽喉   637篇
儿科学   624篇
妇产科学   692篇
基础医学   312篇
口腔科学   2646篇
临床医学   4173篇
内科学   5076篇
皮肤病学   457篇
神经病学   1820篇
特种医学   984篇
外科学   3831篇
综合类   56篇
现状与发展   12篇
预防医学   2689篇
眼科学   321篇
药学   198篇
中国医学   8篇
肿瘤学   2582篇
  2024年   135篇
  2023年   1090篇
  2022年   353篇
  2021年   632篇
  2020年   1213篇
  2019年   483篇
  2018年   1326篇
  2017年   1294篇
  2016年   1512篇
  2015年   1566篇
  2014年   1960篇
  2013年   2374篇
  2012年   769篇
  2011年   734篇
  2010年   1366篇
  2009年   1954篇
  2008年   743篇
  2007年   500篇
  2006年   644篇
  2005年   461篇
  2004年   320篇
  2003年   286篇
  2002年   247篇
  2001年   383篇
  2000年   274篇
  1999年   380篇
  1998年   500篇
  1997年   481篇
  1996年   533篇
  1995年   387篇
  1994年   300篇
  1993年   259篇
  1992年   173篇
  1991年   153篇
  1990年   136篇
  1989年   141篇
  1988年   122篇
  1987年   121篇
  1986年   99篇
  1985年   92篇
  1984年   75篇
  1983年   89篇
  1982年   82篇
  1981年   67篇
  1980年   45篇
  1979年   32篇
  1978年   32篇
  1977年   43篇
  1976年   31篇
  1975年   27篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
131.
132.
133.
134.
135.
136.
Certain ethanol-related diseases in humans have been linked to disorders of immunity. Although humoral and cellular immunity have been studied, the precise mechanisms whereby ethanol use leads to tissue damage remain unknown. In order to explore the hypothesis that ethanol may lead to alteration in expression of tissue Class I major histocompatibility antigen causing an autoimmune phenomenon, a population of acutely ethanol-intoxicated patients was studied. Measurement of Class I major histocompatibility antigen on peripheral blood lymphocytes in this population showed a highly significant (p less than 0.01) increase over controls. The role that this increased antigenicity may play in the evolution of clinical disease is discussed.  相似文献   
137.
A multiple-center study was performed to determine the relationship between lower esophageal contractility, clinical signs, and anesthetic concentration as expressed by minimum alveolar concentration (MAC). One hundred four American Society of Anesthesiologists Class I through III patients were exposed to isoflurane (with and without nitrous oxide) or halothane in concentrations of 0.5, 1.0, and 1.5 MAC. Heart rate and systolic blood pressure were continuously monitored. Both the amplitude and frequency of spontaneous and provoked lower esophageal contractions were measured in situ by using a 24-F probe equipped with provoking and measuring balloons. Combined results demonstrated statistically significant correlations (P<0.001) between lower esophageal contractility and MAC. Spontaneous lower esophageal contractions decreased from 1.10±0.12 (SEM) contractions per minute (0.5 MAC) to 0.42±0.05 (1 MAC) to 0.18±0.05 (1.5 MAC). Provoked lower esophageal contractility values decreased from 45±4 mm Hg (0.5 MAC) to 29±3 (1 MAC) to 19±2 (1.5 MAC). Heart rate changes did not correlate with MAC, and systolic blood pressure correlated in only one of three centers. Intracenter and intercenter analyses failed to demonstrate a significant relationship between lower esophageal contractility and heart rate or systolic blood pressure. No intracenter differences in either amplitude or frequency of lower esophageal contractions were observed, despite differences in volatile agents, induction techniques and agents, patient populations, and duration of anesthesia. Our studies indicate that lower esophageal contractility may be an indicator of anesthetic depth as reflected by MAC, but further studies are needed to quantify the effects of surgical stimulus, intravenous anesthetics, vasodilators, anticholinergics, calcium channel blockers, beta-adrenergic agonists, and the presence of a nasogastric tube.  相似文献   
138.
Commonly used neuropsychological tests were administered to 91 detoxified alcoholics at the beginning of treatment. Statistically significant relationships were observed between test scores and post treatment consumption determined 8 months after completing treatment for 72 patients. The results varied depending upon the particular measure of posttreatment consumption evaluated and the type of statistical analysis used. The most consistent relationships were often counter to the notion that increased neuropsychological performance is correlated with a more favorable treatment outcome. Neuropsychological evaluation is of limited clinical utility in predicting posttreatment alcohol consumption.  相似文献   
139.
Objective To develop and validate a consensus set of retrieval categories for how children remember what they have eaten, and to relate retrieval categories to accuracy of reporting items eaten during school lunch.Design A Delphi technique study was conducted using 10 psychologists. The subject matter consisted of responses transcribed from interviews conducted with 89 randomly selected fourth graders within 90 minutes of eating. Retrieval categories were evaluated for accuracy by comparing students’ self-reported lunch intake with observation.Statistical analyses For round 1, a centroid hierarchical cluster analysis was used to identify common sets of rating pairs to propose categories for reaching consensus. For rounds 2 and 3, percent of agreement was calculated. Accuracy was tabulated across meal items and student use by retrieval category.Results After round 3, we found that 23 “near-consensus”categories were used by at least eight raters. Six categories were used 60% of the time, 4 were used 20% of the time, and 5 were used 15% of the time. Less frequently used categories were combined with similar, more frequently used categories for a total of 16 categories. Students used a large variety of retrieval categories when accurately reporting consumption. Of the 16 categories, 12 were used similarly by both accurate and inaccurate students. Where there were differences in accuracy by retrieval category, the more accurate students used “taste/smell/texture”and “visual”in deference to “order items consumed”and “oral cue still present.”Applications These categories provide insight into the broad range of retrieval categories that children use and provide direction for researchers to design and study specific cues to enhance the accuracy of children's self-reports of diet. J Am Diet Assoc. 1997;97:31–36.  相似文献   
140.
Erythromycin-Induced Immune Hemolytic Anemia   总被引:2,自引:0,他引:2  
A 3-year-old female receiving Pediazole (erythromycin ethylsuccinate and sulfisoxazole) for tonsillitis and otitis media developed severe hemolytic anemia. No serum drug-dependent antibodies could be demonstrated with an in vitro 'immune-complex' method using Pediazole, pure erythromycin ethylsuccinate or pure sulfisoxazole. However, a method using red cells coated with erythromycin base showed in vitro lysis of the erythromycin-coated red cells. This is only the second case of immune hemolytic anemia associated with erythromycin and the first where in vitro drug-dependent hemolysis was demonstrable.  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