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   26789篇
  免费   1810篇
  国内免费   117篇
耳鼻咽喉   227篇
儿科学   706篇
妇产科学   449篇
基础医学   3909篇
口腔科学   366篇
临床医学   2530篇
内科学   6457篇
皮肤病学   693篇
神经病学   2221篇
特种医学   975篇
外国民族医学   3篇
外科学   3818篇
综合类   292篇
一般理论   28篇
预防医学   1967篇
眼科学   501篇
药学   1642篇
  1篇
中国医学   57篇
肿瘤学   1874篇
  2021年   343篇
  2020年   229篇
  2019年   368篇
  2018年   438篇
  2017年   300篇
  2016年   363篇
  2015年   431篇
  2014年   636篇
  2013年   968篇
  2012年   1414篇
  2011年   1567篇
  2010年   980篇
  2009年   991篇
  2008年   1501篇
  2007年   1672篇
  2006年   1661篇
  2005年   1775篇
  2004年   1609篇
  2003年   1529篇
  2002年   1521篇
  2001年   410篇
  2000年   339篇
  1999年   404篇
  1998年   423篇
  1997年   381篇
  1996年   339篇
  1995年   309篇
  1994年   294篇
  1993年   265篇
  1992年   317篇
  1991年   305篇
  1990年   271篇
  1989年   266篇
  1988年   257篇
  1987年   230篇
  1986年   242篇
  1985年   245篇
  1984年   212篇
  1983年   201篇
  1982年   228篇
  1981年   238篇
  1980年   191篇
  1979年   143篇
  1978年   138篇
  1977年   144篇
  1976年   125篇
  1975年   114篇
  1974年   101篇
  1973年   93篇
  1972年   91篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
To determine the prevalence of excessive daytime sleepiness (EDS) and that of dozing and sudden onset of sleep episodes (SOS) while driving in ambulatory patients with Parkinson's disease (PD) in France, a national sample of private and public neurologists was asked to recruit the first 10 consecutive nondemented PD patients. Each patient completed a questionnaire including the Epworth Sleepiness Scale (ESS) and the likelihood of dozing off and experiencing SOS episodes behind the wheel. Clinical and demographic data were collected. One thousand six hundred and twenty‐five patients with PD were included in the survey. Twenty‐nine percent of the patients suffered from EDS (ESS score ≥10) but only 0.8% declared a high chance of dozing while driving and 0.5% reported totally unpredictable SOS episodes while driving. Risk factors for EDS were male gender, reduced activity of daily living, and a high daily levodopa equivalent dosage. Risk factors for SOS episodes while driving were an ESS score ≥10, male gender, and low Hoehn and Yahr staging. EDS is common in ambulatory patients with PD and is a major risk factor for dozing and for SOS episodes behind the wheel in patients who drive. © 2007 Movement Disorder Society  相似文献   
62.
A significant reduction of kallikrein activity in urine (assayed by its amidolytic activity) was found in 64 normotensive workers who had been exposed to cadmium for 11 years on average and whose cadmium concentrations in urine ranged from 2.2 to 33.1 micrograms/g creatinine. The mean (geometric) urinary kallikrein activity (in U/g creatinine) amounted to 0.52 (range 0.11-1.90) in the control group (n = 193) against 0.39 (range 0.10-1.03) in the cadmium group, and the prevalence of abnormally low activity levels (less than or equal to 0.20 U/g creatinine) amounted to 17.2% in the cadmium group against 5.2% in the control group. A reduction of aldosterone release (aldosterone in urine) associated with an increased natriuresis was also observed. This might constitute a compensatory mechanism maintaining blood pressure in the normal range. These biological effects of cadmium were not reversible after removal from exposure. This study indicates that cadmium can induce an irreversible toxic effect in the distal nephron. It also suggests that an excessive cadmium body burden alone may not be sufficient to induce hypertension, but in individuals whose blood pressure regulation may be impaired by other factors cadmium could stimulate the development of hypertension. This study also supports the recommendation to prevent hypertensive subjects from being exposed to cadmium. There was no indication that moderate exposure to mercury vapour (n = 53; mercury in urine, range 11-224 micrograms/g creatinine; average duration of exposure: six years) or to inorganic lead (n = 23; lead in blood, range 40-67 micrograms/100 ml; average duration of exposure: eight years) was associated with a reduction of kallikrein production by the kidney.  相似文献   
63.
Hepatitis B screening in a New York City obstetrics service.   总被引:1,自引:1,他引:0       下载免费PDF全文
A cross-sectional chart review study was performed of hepatitis B virus (HBV) surface antigen screening of 532 women admitted to a New York City hospital obstetrics service from 1984 to 1985. Comparison of serologic results to risk factors for hepatitis B revealed that women born outside the United States and those with a positive test for or history of a sexually transmitted disease were more likely to be infected with HBV. Obstetric clinics with large immigrant populations should consider screening all patients for HBV.  相似文献   
64.
Amiodarone hydrochloride is a potent antiarrhythmic agent recently approved for use by the Food and Drug Administration. Anterior subcapsular lens opacities were observed in seven of fourteen patients treated with moderate to high doses of amiodarone at the Veterans Administration Medical Center in San Francisco in 1982. The present report summarizes the present status of these same fourteen patients ten years later. Anterior subcapsular lens opacities developed or progressed in all patients continuing treatment with this antiarrhythmic agent during the following ten year interval. Although Snellen visual acuities are not decreased, subtle visual impairment is present as measured by contrast sensitivity measurements with and without glare. This decrease in visual acuity is not a contraindication for therapy with this potentially life saving drug.  相似文献   
65.
66.
67.

Background  

A total of 137 consecutive patients with recent uncomplicated myocardial infarction (n=31) or unstable angina (n=106) were studied to determine the relative prognostic value of predischarge clinical risk stratification and intravenous dipyridamole stress sestamibi (MIBI) myocardial tomography in patients unable to exercise maximally after an acute ischemic coronary event.  相似文献   
68.
69.
This paper summarizes the findings of the Cadmibel Study, a cross-sectional population study of the health effects of cadmium, but only with respect to the cardiovascular system and calcium metabolism. The study disproved the hypothesis that exposure to cadmium would lead to an increase in blood pressure and in the prevalence of hypertension and other cardiovascular diseases. On the other hand, there was a positive relationship between urinary cadmium (Cd-U) and both serum alkaline phosphatase activity and urinary excretion of calcium. The regression coefficients obtained after adjustment for significant co-variates indicated that, when Cd-U increased two-fold, serum alkaline phosphatase and urinary calcium rose by 4% and 0.25 mmol/24 h, respectively. These findings suggest that calcium metabolism is gradually affected as cadmium accumulates in the body. The morbidity associated with the latter phenomenon is still unknown, and requires further investigation, preferably in a longitudinal prospective population study, in which the incidence of morbid events would be monitored in relation to the cadmium body burden.  相似文献   
70.
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