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   517642篇
  免费   33568篇
  国内免费   620篇
耳鼻咽喉   6905篇
儿科学   16956篇
妇产科学   13562篇
基础医学   85492篇
口腔科学   14556篇
临床医学   44613篇
内科学   94503篇
皮肤病学   12217篇
神经病学   36565篇
特种医学   18547篇
外国民族医学   63篇
外科学   77556篇
综合类   8505篇
一般理论   118篇
预防医学   39094篇
眼科学   12177篇
药学   40859篇
中国医学   1006篇
肿瘤学   28536篇
  2018年   4983篇
  2015年   4559篇
  2014年   6103篇
  2013年   9628篇
  2012年   12995篇
  2011年   14436篇
  2010年   8382篇
  2009年   7844篇
  2008年   13832篇
  2007年   14815篇
  2006年   15087篇
  2005年   14508篇
  2004年   14215篇
  2003年   13531篇
  2002年   13435篇
  2001年   24192篇
  2000年   25217篇
  1999年   20698篇
  1998年   5481篇
  1997年   4748篇
  1996年   5077篇
  1995年   4654篇
  1994年   4337篇
  1993年   4159篇
  1992年   15847篇
  1991年   16417篇
  1990年   16544篇
  1989年   15923篇
  1988年   14711篇
  1987年   14504篇
  1986年   13671篇
  1985年   13042篇
  1984年   9699篇
  1983年   8283篇
  1982年   4570篇
  1981年   4241篇
  1979年   9471篇
  1978年   6881篇
  1977年   5808篇
  1976年   5624篇
  1975年   6415篇
  1974年   7651篇
  1973年   7148篇
  1972年   6979篇
  1971年   6701篇
  1970年   6183篇
  1969年   5896篇
  1968年   5569篇
  1967年   5024篇
  1966年   4459篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Factors associated with levels of physical activity at work and during leisure time were analyzed among 577 subjects who had been selected as population controls for a case-control study by random selection from telephone directories. The intensity of physical activity at work was inversely associated with body mass index, the proportion of professionals & managers, consumption of western style breakfast, coffee, butter/margarine, and whisky; and positively associated with rice intake. Frequency of physical activities during leisure time was positively associated with consumption of vegetables, fruits, mushrooms, milk, cheese and coffee, and moderation in eating; and inversely associated with rice intake and the prevalence of gastrointestinal symptoms and medication. The association of physical activity with these factors should be considered in studying its relationship to disease risk.  相似文献   
52.
This paper examines the effect of patient age, tumour grade and extent of surgery on the outcome of treatment of 278 patients with high grade malignant gliomas referred to the Queensland Radium Institute between 1980 and 1987. The aim was to determine whether the extent of surgical resection alters survival rates. The extent of surgery had no effect on survival except for those patients with grade 3 tumours in whom a total excision was possible. Those in whom only a biopsy was done did not have a worse prognosis. Grading was found to be of importance, as patients with grade 3 tumours had a better survival than those with grade 4 tumours. In grade 4 tumours, those under 30 years of age had a better survival than those over 30 years, whereas with grade 3 tumours there was a gradation of age effect (under 40 years best, then 40–49 years, and those 50 years and over doing worst).  相似文献   
53.
54.
55.
56.
57.
Three hundred and twenty samples of subgingival plaque were obtained from 80 caucasian girls, ranging from 10 to 13 years of age. The samples were analyzed to verify the influence of age upon colonization of the gingival sulcus by microorganisms potentially pathogenic to the periodontal tissues. The gingival and plaque status were evaluated through the gingival index (GI) and plaque index (PlI) and the microflora was assessed by the enzymatic method benzoyl-arginine-naphthylamide (BANA). The results of the BANA test were positive for 62.50% of the tested individuals and 40% of the examined sites. The influence of age was statistically significant on BANA reactivity, and the number of positive sites was greater at 11 (57.5%) than at 12 years (28.8%).  相似文献   
58.
59.
60.
Variations of the medial and inferior choanal limits may facilitate snoring. These are: 1) short vomer without crista choanalis vomeris and adaptational formations, 2) extremely concave posterior margin of the hard palate leading to disproportion between the muscular and aponeurotic part of m. tensor veli palatini and hence to a flabby soft palate especially during sleep, and 3) neonatal relation of the height and width of the choane resulting in a very large choanal region instead of relative reduction of choanal width compared to its increasing height. All these variations result in a flabby soft palate especially during sleep and may lead to formation of whirles of inspired air and snoring.  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