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   2405472篇
  免费   182133篇
  国内免费   4908篇
耳鼻咽喉   33502篇
儿科学   79783篇
妇产科学   69241篇
基础医学   346574篇
口腔科学   66961篇
临床医学   212867篇
内科学   471913篇
皮肤病学   53812篇
神经病学   192849篇
特种医学   92553篇
外国民族医学   793篇
外科学   364678篇
综合类   54131篇
现状与发展   4篇
一般理论   743篇
预防医学   185423篇
眼科学   55278篇
药学   176087篇
  2篇
中国医学   5227篇
肿瘤学   130092篇
  2018年   25439篇
  2017年   19329篇
  2016年   21879篇
  2015年   24761篇
  2014年   34704篇
  2013年   52129篇
  2012年   70960篇
  2011年   75652篇
  2010年   44627篇
  2009年   42292篇
  2008年   71217篇
  2007年   76106篇
  2006年   77086篇
  2005年   74945篇
  2004年   72072篇
  2003年   69123篇
  2002年   67490篇
  2001年   113381篇
  2000年   116187篇
  1999年   97546篇
  1998年   27929篇
  1997年   25141篇
  1996年   25241篇
  1995年   23966篇
  1994年   22053篇
  1993年   20729篇
  1992年   75996篇
  1991年   73691篇
  1990年   71829篇
  1989年   69233篇
  1988年   63901篇
  1987年   62679篇
  1986年   59162篇
  1985年   56423篇
  1984年   42636篇
  1983年   36602篇
  1982年   22025篇
  1981年   19572篇
  1979年   39022篇
  1978年   27622篇
  1977年   23335篇
  1976年   22157篇
  1975年   23646篇
  1974年   28135篇
  1973年   27121篇
  1972年   25624篇
  1971年   23584篇
  1970年   22213篇
  1969年   21025篇
  1968年   19774篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
951.
Bipolar disorder is a serious mental illness affecting a large number of Americans. While lithium, the treatment of choice for this disorder, is usually effective, a substantial number of individuals with bipolar disorder are not helped by lithium or are intolerant to its side effects. Consequently, investigators are searching for alternative drugs in order to treat lithium-resistant patients. Although a number of alternative drug treatments have been discussed in the literature, only the anticonvulsants carbamazepine and valproate appear to warrant serious consideration at this time. Future research will further define their roles as antimanic agents.  相似文献   
952.
This study was performed to gain a better understanding of EEG frequency analysis test-retest reliability in normal healthy adults, and to evaluate factors which could influence the measured inter-record differences. Nineteen subjects underwent serial EEG recordings at 5 min and 12-16 week intervals. Records were visually edited using a standardized protocol, and FFT frequency analysis performed on segments of 60, 40, or 20 sec total length. Correlation coefficients for broad band features averaged 0.92 over the 5 min retest interval and 0.84 over the 12-16 week interval. There was essentially no difference between correlation coefficients of absolute and relative power features. Coefficients based on 60 sec records were marginally higher than those of 40 or 20 sec records. On the other hand, test-retest percent differences were typically lower for relative as opposed to absolute power features, and 60 sec records showed consistently lower percent differences than did 40 or particularly 20 sec records. Peak alpha frequency and mean frequency were the most stable EEG features at either interval. Montage had significant effects on test-retest differences at the 12-16 week interval. A significant association between intra-record and inter-record variability could not be demonstrated.  相似文献   
953.
N C Tuazon 《Nursing》1991,21(11):143-144
  相似文献   
954.
955.
BACKGROUND. Studies have documented the potential contributions of preventive health care programs. Yet little is known about which screening tests should be included in public health programs for older persons. This study offers recommendations regarding these tests. METHODS. The recommendations come from synthesizing the findings of the US Preventive Services Task Force, the literature, and the consensus of experts in geriatrics, gerontology, and health policy research. The literature was evaluated to identify methodologically sound studies of the prevalence of selected disorders and benefits and availability of screening procedures for those disorders. Experts from various fields specializing in the care of the elderly formed panels to assist in evaluating the literature and providing further information from gerontological and public health perspectives. RESULTS. We recommend vision testing for refractive error; inspection of the skin surface for fungal infection and skin cancer, drug eruptions, and xerosis; a history for symptoms of xerosis; audiometric testing for presbycusis; surveys for hearing loss; otoscopic inspection for cerumen impaction; dental examination for caries; measurement of blood pressure for hypertension; and breast examination and mammography for cancer. CONCLUSIONS. Our study suggests that these screening procedures are useful for public health screening programs. More information is needed on the effects of screening services on the health and functioning of older persons.  相似文献   
956.
957.
958.
In the processing of the waste products of phosphorus containing fertilizer production, several major health-related factors were identified depending on the industrial site's peculiarities: unfavourable microclimate conditions (both cold and heat), relative temperature differences, noise and vibration caused by the equipment, semi-product's, additives' and finished product's dusts, fluorine- and phosphorus-containing substances' affects and poor illumination. The proposed data were used for health-related improvements in the occupational conditions.  相似文献   
959.
NTS fallout-induced multiple myeloma in Utah.   总被引:1,自引:0,他引:1  
  相似文献   
960.
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