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   8680篇
  免费   771篇
  国内免费   46篇
耳鼻咽喉   88篇
儿科学   376篇
妇产科学   143篇
基础医学   1128篇
口腔科学   245篇
临床医学   909篇
内科学   1975篇
皮肤病学   160篇
神经病学   729篇
特种医学   651篇
外国民族医学   2篇
外科学   1100篇
综合类   97篇
一般理论   1篇
预防医学   688篇
眼科学   144篇
药学   430篇
中国医学   16篇
肿瘤学   615篇
  2023年   39篇
  2022年   70篇
  2021年   201篇
  2020年   95篇
  2019年   252篇
  2018年   284篇
  2017年   202篇
  2016年   203篇
  2015年   236篇
  2014年   269篇
  2013年   394篇
  2012年   421篇
  2011年   407篇
  2010年   326篇
  2009年   264篇
  2008年   351篇
  2007年   376篇
  2006年   371篇
  2005年   324篇
  2004年   262篇
  2003年   257篇
  2002年   279篇
  2001年   186篇
  2000年   220篇
  1999年   199篇
  1998年   199篇
  1997年   188篇
  1996年   177篇
  1995年   143篇
  1994年   123篇
  1993年   120篇
  1992年   164篇
  1991年   177篇
  1990年   143篇
  1989年   190篇
  1988年   162篇
  1987年   147篇
  1986年   155篇
  1985年   121篇
  1984年   91篇
  1983年   85篇
  1982年   57篇
  1981年   47篇
  1980年   61篇
  1979年   64篇
  1978年   37篇
  1977年   45篇
  1976年   52篇
  1975年   44篇
  1973年   35篇
排序方式: 共有9497条查询结果,搜索用时 15 毫秒
11.
Transplantation of retinal epithelial cells   总被引:4,自引:0,他引:4  
  相似文献   
12.
13.

Background  

Almost 400,000 deaths are registered each year in Thailand. Their value for public health policy and planning is greatly diminished by incomplete registration of deaths and by concerns about the quality of cause-of-death information. This arises from misclassification of specified causes of death, particularly in hospitals, as well as from extensive use of ill-defined and vague codes to attribute the underlying cause of death. Detailed investigations of a sample of deaths in and out of hospital were carried out to identify misclassification of causes and thus derive a best estimate of national mortality patterns by age, sex, and cause of death.  相似文献   
14.
In an attempt to study further the possible participation of platelets in the pathogenesis of acute poststreptococcal glomerulonephritis (APSGN), we studied the platelet survival time, as an index of platelet activation, in 22 patients with APSGN. Mean platelet survival time was computed from the disappearance of radioactivity from blood, sampled serially after injection of autologous 51Cr-labelled platelets. C1q solid phase ELISA and conglutinin (K) solid phase ELISA were used to measure the serum levels of immune complexes. The platelet survival time in APSGN patients was 113 +/- 10 h vs 197 +/- 10 h in the control group (p less than 0.001); 68% of the patients had a shortened platelet survival, lower than 95% confidence limit. There was a significant increase in the platelet survival in the six patients that were studied after recovery from acute nephritic syndrome. There was no significant association between the mean platelet times survival and CICs (circulating immune complexes). Similarly, no significant correlation was found between the mean platelet lifespan and the severity of the glomerular disease, as assessed by the serum creatinine level and the proteinuria. These results support evidence of platelet activation and consumption in APSGN and we suggest that this activation occurs in the glomeruli capillary wall, due to platelet-vascular wall interaction.  相似文献   
15.
The etiological diagnosis of obstruction is difficult during pregnancy. The authors report 3 cases of this rare association: obstruction due to adhesions [1], volvulus of the transverse colon on a common mesentery [1] and obstruction due to an appendix abscess [1]. Complementary investigations, obviously limited under these circumstances, were based on plain abdominal X-rays, repeated if necessary. The diagnosis must be made early and appropriate treatment given in order to ensure a good materno-fetal prognosis as was obtained in these 3 cases.  相似文献   
16.
17.
18.
L-acetylcarnitine is a compound with cholinergic properties and putative action on the visual system and the glucose metabolism. Ten healthy, emmertropic volunteers (age range: 21 to 28 years) were studied. Each subject was administered 5, 10, and 30 mg/kg acute intravenous doses of L-acetylcarnitine and matching placebo. Retinal oscillatory potentials to full-field flash stimulation were recorded before and 30, 60, and 120 min after administration. A systematic reduction of the implicit time of the P2 and N2 oscillatory potential components was observed after administration of the 10 and 30 mg/kg doses: significant changes were not evident at the 5 mg dose or after placebo. The latency reduction was significantly correlated with the postdrug increment of the L-acetylcarnitine plasma concentration. No other systematic modification in latency of amplitude was observed.The results were presented in part at the XXV I.S.C.E.V. Symposium, Sarasota (Florida), April 26–30, 1987.  相似文献   
19.
OBJECTIVES: The purpose of this study was to determine quality of life (QOL) and exercise performance (EP) in patients with persistent atrial fibrillation (AF) converted to sinus rhythm (SR) compared with those remaining in or reverting to AF. BACKGROUND: Restoration of SR in patients with AF improving QOL and EP remains controversial. METHODS: Patients with persistent AF were randomized double-blind to amiodarone, sotalol, or placebo. Those not achieving SR at day 28 were cardioverted and classified into SR or AF groups at 8 weeks (n = 624) and 1 year (n = 556). The QOL (SF-36), symptom checklist (SCL), specific activity scale (SAS), AF severity scale (AFSS), and EP were assessed. RESULTS: Favorable changes were seen in SR patients at 8 weeks in physical functioning (p < 0.001), physical role limitations (p = 0.03), general health (p = 0.002), and vitality (p < 0.001), and at 1 year in general health (p = 0.007) and social functioning (p = 0.02). Changes in the scores for SCL severity (p = 0.01), functional capacity (p = 0.003), and AFSS symptom burden (p < 0.001) at 8 weeks and in SCL severity (p < 0.01) and AF symptom burden (p < 0.001) at 1 year showed significant improvements in SR versus AF. Symptomatic patients were more likely to have improvement. The EP in SR versus AF was greater from baseline to 8 weeks (p = 0.01) and to 1 year (p = 0.02). The EP correlated with physical functioning and functional capacity except in the AF group at 1 year. CONCLUSIONS: In patients with persistent AF, restoration and maintenance of SR was associated with improvements in QOL measures and EP. There was a strong correlation between QOL measures and EP.  相似文献   
20.
Hypertension in developing countries   总被引:2,自引:0,他引:2  
Population surveys carried out since the 1970s in 15 developing countries including 23 population groups show that the prevalence of hypertension ranges from as low as 1% in some African countries to over 30% in Brazil. A trend analysis of the mortality statistics for 35-74 year-olds from 16 countries in which data are available shows a downward trend in mortality from hypertension and cerebrovascular diseases in most of these countries. In spite of the current low prevalence in some countries, the total number of hypertensives in the developing world is high, and a cost assessment of possible antihypertensive drug treatment indicates that developing countries cannot afford the same drug treatment levels as developed countries.  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