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   3487篇
  免费   249篇
  国内免费   19篇
耳鼻咽喉   21篇
儿科学   133篇
妇产科学   196篇
基础医学   419篇
口腔科学   116篇
临床医学   334篇
内科学   580篇
皮肤病学   58篇
神经病学   368篇
特种医学   277篇
外科学   352篇
综合类   54篇
一般理论   4篇
预防医学   339篇
眼科学   31篇
药学   244篇
中国医学   2篇
肿瘤学   227篇
  2021年   37篇
  2020年   35篇
  2019年   57篇
  2018年   58篇
  2017年   43篇
  2016年   38篇
  2015年   57篇
  2014年   64篇
  2013年   101篇
  2012年   145篇
  2011年   129篇
  2010年   87篇
  2009年   86篇
  2008年   110篇
  2007年   149篇
  2006年   101篇
  2005年   116篇
  2004年   102篇
  2003年   95篇
  2002年   96篇
  2001年   117篇
  2000年   112篇
  1999年   100篇
  1998年   62篇
  1997年   69篇
  1996年   70篇
  1995年   37篇
  1994年   45篇
  1993年   50篇
  1992年   70篇
  1991年   75篇
  1990年   59篇
  1989年   83篇
  1988年   70篇
  1987年   79篇
  1986年   89篇
  1985年   101篇
  1984年   74篇
  1983年   61篇
  1982年   30篇
  1981年   35篇
  1980年   36篇
  1979年   43篇
  1978年   40篇
  1977年   35篇
  1976年   40篇
  1975年   38篇
  1973年   30篇
  1972年   32篇
  1969年   27篇
排序方式: 共有3755条查询结果,搜索用时 15 毫秒
21.
Fatal occupational injuries in the United States, 1980 through 1985   总被引:12,自引:0,他引:12  
C A Bell  N A Stout  T R Bender  C S Conroy  W E Crouse  J R Myers 《JAMA》1990,263(22):3047-3050
The National Traumatic Occupational Fatality surveillance project was designed to gather demographic, employment, and injury information from death certificates for all deaths due to injuries at work in the United States. Approximately 7000 workers have died each year during the 6-year period from 1980 through 1985: 94% were men, and 6% were women. Unintentional injuries caused the deaths of 83% of the men and 50% of the women. Eleven percent of the men and 39% of the women died from homicide. While the greatest number of deaths occurred in the group aged 20 through 34 years, fatality rates were highest among those aged 70 years and older. Expressed as deaths per 100,000 workers, annual fatality rates for black workers (7.7) were slightly higher than for white workers (6.5). The four industrial groups with the highest fatality rates were mining (31.9); transportation, communication, and public utilities (25.4); construction (24.0); and agriculture, forestry, and fishing (20.7). From 1980 through 1985 the annual traumatic occupational fatality rate fell 23%.  相似文献   
22.
In a randomized, double-blind parallel group study the 24-hour hypotensive effect of piretanide and its influence on biochemical variables were compared with those of placebo in patients with mild to moderate essential hypertension. Sixty patients entered the study, all of whom met the inclusion criteria (RRdiast between 95 and 120 mmHg). There was no drop-out during the study, so that the results of all 60 patients were statistically analysed. Piretanide produced a significant reduction of both systolic and diastolic blood pressure over 24 hours which was evident at four weeks and was maintained and further enhanced over the ensuing trial period. A mean maximal fall (at 12 weeks) of 10.7% (BPdiast supine) was observed. Placebo tablets did not produce any clinically relevant changes in systolic blood pressure, whereas a slight decrease was seen in diastolic blood pressure. This blood pressure reduction was significantly less in the placebo group than in the piretanide group at the end of the study (weeks 10 and 12). Dose doubling was needed in 13 of the 30 patients in the piretanide group, whereas as many as 20 out of 30 patients needed dose doubling in the placebo group. Pulse rate did not change relevantly during the trial in either group. A slight reduction in body weight was observed in the piretanide group. The mean values of serum potassium and sodium showed a slight decrease but remained within the normal range during the study period. A small increase in serum phosphorus was noted. None of these changes required any specific measures.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
23.
24.
The basic principles of the operative treatment of lumbar spondylolisthesis became uniform in the literature in the last years. Authors deal shortly with some questions of the indication and of the preoperative examination and describe shortly the basic principles of the operative treatment (decompression, reduction, stabilization). The operative methods used by them are reported and illustrated (Morscher's "hookscrew" method, fusion according to Harrington-Vidal, Cloward's posterior corpodesis--PLIF--and Steffee's transpedicular system).  相似文献   
25.
Genetic testing in a multisite clinical trial network for inherited eye conditions is described in this retrospective review of data collected through eyeGENE®, the National Ophthalmic Disease Genotyping and Phenotyping Network. Participants in eyeGENE were enrolled through a network of clinical providers throughout the United States and Canada. Blood samples and clinical data were collected to establish a phenotype:genotype database, biorepository, and patient registry. Data and samples are available for research use, and participants are provided results of clinical genetic testing. eyeGENE utilized a unique, distributed clinical trial design to enroll 6,403 participants from 5,385 families diagnosed with over 30 different inherited eye conditions. The most common diagnoses given for participants were retinitis pigmentosa (RP), Stargardt disease, and choroideremia. Pathogenic variants were most frequently reported in ABCA4 (37%), USH2A (7%), RPGR (6%), CHM (5%), and PRPH2 (3%). Among the 5,552 participants with genetic testing, at least one pathogenic or likely pathogenic variant was observed in 3,448 participants (62.1%), and variants of uncertain significance in 1,712 participants (30.8%). Ten genes represent 68% of all pathogenic and likely pathogenic variants in eyeGENE. Cross‐referencing current gene therapy clinical trials, over a thousand participants may be eligible, based on pathogenic variants in genes targeted by those therapies. This article is the first summary of genetic testing from thousands of participants tested through eyeGENE, including reports from 5,552 individuals. eyeGENE provides a launching point for inherited eye research, connects researchers with potential future study participants, and provides a valuable resource to the vision community.  相似文献   
26.
This study examined risk and protective factors that differentiate low-income, abused African American women (N = 200) who attempted suicide from those who had never made a suicide attempt. Results from multivariate analyses revealed that numerous and/or severe negative life events, a history of child maltreatment, high levels of psychological distress and depression, hopelessness about the future, and alcohol and drug problems were factors associated with attempter status. Protective factors associated with nonattempter status included hopefulness, self-efficacy, coping skills, social support, and effectiveness in obtaining material resources. Culturally competent intervention approaches for abused women should target increasing their protective factors and reducing their risk factors to decrease the likelihood that these women engage in suicidal behavior.  相似文献   
27.
Previous studies have established that inactivated mycobacteria are potent and selective activators of V gamma 9+/V delta 2+ human gamma/delta T cells. Here we have analysed the proliferative response of human gamma/delta T cells to five serologically distinct groups of streptococci. While heat-inactivated streptococci of all five serogroups tested (A, B, C, D and F) induced a strong proliferative response in peripheral blood mononuclear cells (PBMC), only groups A, B and C elicited a selective activation of V gamma 9+ gamma/delta T cells in 10 (serogroup B) or 11 (serogroups A and C) of 11 tested healthy individuals. In striking contrast, groups D and F streptococci failed to activate gamma/delta T cells in nine of 11 donors and induced only a weak gamma/delta T cell response in two additional individuals. Depletion of V gamma 9+ T cells before culture completely eliminated all gamma/delta T cell responses to streptococci. These data indicate that groups A, B and C (but not D or F) streptococci can be included in the growing list of selective ligands for V gamma 9+/V delta 2+ human gamma/delta T cells.  相似文献   
28.
29.
30.
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