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   2350369篇
  免费   171232篇
  国内免费   3331篇
耳鼻咽喉   32049篇
儿科学   75898篇
妇产科学   62692篇
基础医学   348213篇
口腔科学   63635篇
临床医学   211359篇
内科学   457333篇
皮肤病学   51729篇
神经病学   185281篇
特种医学   88016篇
外国民族医学   489篇
外科学   353884篇
综合类   47511篇
现状与发展   12篇
一般理论   848篇
预防医学   182741篇
眼科学   54329篇
药学   175114篇
  11篇
中国医学   4575篇
肿瘤学   129213篇
  2021年   18984篇
  2019年   19537篇
  2018年   27059篇
  2017年   20358篇
  2016年   22747篇
  2015年   25639篇
  2014年   36100篇
  2013年   53956篇
  2012年   74684篇
  2011年   79415篇
  2010年   47062篇
  2009年   44570篇
  2008年   74614篇
  2007年   79486篇
  2006年   80302篇
  2005年   77788篇
  2004年   74378篇
  2003年   71697篇
  2002年   69371篇
  2001年   108738篇
  2000年   111453篇
  1999年   93499篇
  1998年   26993篇
  1997年   23661篇
  1996年   24056篇
  1995年   22718篇
  1994年   20895篇
  1993年   19714篇
  1992年   72002篇
  1991年   70075篇
  1990年   68392篇
  1989年   65666篇
  1988年   60305篇
  1987年   59132篇
  1986年   55219篇
  1985年   53004篇
  1984年   39312篇
  1983年   33396篇
  1982年   19858篇
  1979年   35867篇
  1978年   25654篇
  1977年   21233篇
  1976年   20332篇
  1975年   21816篇
  1974年   26149篇
  1973年   24805篇
  1972年   23202篇
  1971年   22037篇
  1970年   20249篇
  1969年   19316篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
991.
992.
993.
Blood alcohol level among emergency room patients: a multivariate analysis   总被引:2,自引:0,他引:2  
This article examines the distribution of positive blood alcohol levels (BALs) among emergency room patients and the relationship between intoxication and other variables. Approximately one-quarter of the 640 subjects had positive blood alcohol levels and 16.3% had BAL readings above 0.10%, the legal limit for operating a motor vehicle in most states. Chi-square tests and logistic regression analysis indicated a significant relationship between employment status, gender, educational attainment, age and BAL. There were no significant racial differences. Analysis of the role of the presenting problem with BAL revealed that being involved in an accident was significantly predictive of a high BAL in a multivariate context. However, patients presenting with psychiatric problems had overall higher levels of intoxication than other patients. These findings have major implications for public policy formulation vis-à-vis public health delivery.  相似文献   
994.
Using a 31P-NMR spectroscopy, we monitored the metabolic kinetics of energy organophosphate compound in rat lens during the process of generating galactose cataract. The most remarkable metabolic change in the earlier phase of galactose cataract formation was found in alpha-glycerophosphate. This increased significantly, as compared to controls, since the day 3 of giving feed containing 25% galactose. The high level lasted for up to three weeks, decrease followed by a gradual decrease and subsequently a significant decrease at five weeks. Adenosine triphosphate (ATP) showed a significant decrease in the galactose group compared to the controls from two weeks after beginning of the experiment and the decrease continued. Inorganic orthophosphate increased gradually in the galactose group as compared to the controls, the increase being of significance at one week reading a maximum at two weeks followed by a subsegment decrease. Our basic study suggests that 31P-NMR spectroscopy is a useful technique in lens of the metabolic kinetics, to noninvasively determine the pathophysiology of galactose cataract, which has been studied biochemically and histologically.  相似文献   
995.
The epidemiology of viral hepatitis in US Navy enlisted personnel was reviewed for the years 1975-1984. Hospital discharge summaries of all active duty enlisted personnel admitted to a US Navy treatment facility were used for the study. From 1975 to 1984, total first hospitalizations for viral hepatitis declined from 128 per 100,000 personnel (95% confidence interval (Cl) 118-139) to 56 per 100,000 personnel (95% Cl 50-63). The highest incidence of acute viral hepatitis (115 per 100,000 personnel) was found in the youngest age groups aged 24 years and less. Risk factors for acute hepatitis included a previous hospitalization with either drug abuse (relative risk = 363) or a sexually transmitted disease (relative risk = 25) listed among the discharge diagnoses. Having a medical job classification was also associated with an increased risk of acute hepatitis. The steep decline in the incidence of viral hepatitis during this 10-year period may have been due to decreasing drug abuse in the US Navy. Immunization of high-risk groups in the US Navy with hepatitis B vaccine could be an effective policy for the prevention of acute viral hepatitis.  相似文献   
996.
997.
998.
999.
In less than two decades, there has been a dramatic reduction in the prevalence of otitis media and perforations among Guam's school-aged children. In addition, hearing loss due to chronic middle ear disease as a cause of disqualification from military service has dropped from a first rank order cause to next-to-last. However, there has been no reduction in the prevalence of otitis media in the preschool population. The reduction in chronic ear disease is the result of improved access to primary care, intensive hearing screening, wide availability of audiologic diagnostic and follow-up services, and comprehensive otologic care. It is essential that these services continue to be available to Guam's children to avoid a reversal of these dramatic gains. Attention must now focus on how to achieve similar gains for Micronesian children who remain restricted in their access to these resources.  相似文献   
1000.
Thirty-one patients presenting as orbital optic nerve glioma have been reviewed with maximum follow-up of 14 years. Sixteen of these patients have been reported on previously and further follow-up is provided. Sixteen patients had a stable clinical course with little change over a period of up to 13.5 years. Neurofibromatosis was relatively common in this group (11/16). Fifteen patients had progressive enlargement of the tumour; the incidence of neurofibromatosis in this group was low (4/15). Eleven of these patients were explored neurosurgically and the optic nerve totally excised in 10 of them. The proximal cut end was normal in six patients and the chiasm has apparently remained free of tumour in all of them. We suggest a method of management of primary optic nerve tumours, both meningiomas and gliomas, in young patients.  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