全文获取类型
收费全文 | 2232289篇 |
免费 | 180133篇 |
国内免费 | 4133篇 |
专业分类
耳鼻咽喉 | 31687篇 |
儿科学 | 71016篇 |
妇产科学 | 64527篇 |
基础医学 | 318839篇 |
口腔科学 | 66317篇 |
临床医学 | 197023篇 |
内科学 | 430830篇 |
皮肤病学 | 47060篇 |
神经病学 | 181486篇 |
特种医学 | 89618篇 |
外国民族医学 | 632篇 |
外科学 | 341532篇 |
综合类 | 58592篇 |
现状与发展 | 5篇 |
一般理论 | 765篇 |
预防医学 | 174190篇 |
眼科学 | 52297篇 |
药学 | 168186篇 |
3篇 | |
中国医学 | 4258篇 |
肿瘤学 | 117692篇 |
出版年
2018年 | 20486篇 |
2015年 | 20978篇 |
2014年 | 29254篇 |
2013年 | 44678篇 |
2012年 | 60298篇 |
2011年 | 63517篇 |
2010年 | 37407篇 |
2009年 | 35544篇 |
2008年 | 60527篇 |
2007年 | 64639篇 |
2006年 | 65090篇 |
2005年 | 63546篇 |
2004年 | 62538篇 |
2003年 | 59941篇 |
2002年 | 58396篇 |
2001年 | 99563篇 |
2000年 | 102570篇 |
1999年 | 87126篇 |
1998年 | 24696篇 |
1997年 | 22591篇 |
1996年 | 22455篇 |
1995年 | 21679篇 |
1994年 | 20482篇 |
1993年 | 19263篇 |
1992年 | 72660篇 |
1991年 | 70578篇 |
1990年 | 69098篇 |
1989年 | 66752篇 |
1988年 | 62453篇 |
1987年 | 61459篇 |
1986年 | 58460篇 |
1985年 | 56574篇 |
1984年 | 42904篇 |
1983年 | 36898篇 |
1982年 | 22500篇 |
1981年 | 20312篇 |
1980年 | 18976篇 |
1979年 | 41982篇 |
1978年 | 29632篇 |
1977年 | 24958篇 |
1976年 | 23289篇 |
1975年 | 24848篇 |
1974年 | 30638篇 |
1973年 | 29383篇 |
1972年 | 27282篇 |
1971年 | 25708篇 |
1970年 | 23874篇 |
1969年 | 22735篇 |
1968年 | 20641篇 |
1967年 | 18846篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
141.
142.
143.
F. M. RAAPHORST R. LANGLOIS VAN DEN BERGH J. L. M. WAAIJER J. M. VOSSEN & M. J. D. VAN TOL 《Scandinavian journal of immunology》1997,46(3):292-297
Fetal B lymphocytes in mice and humans use a limited number of the available VH gene segments. Mouse fetal B cells primarily utilize 3' VH elements, suggesting that the localization of these elements determines their rearrangement frequency. The previously reported non-random usage of human VH genes has been more difficult to explain. In this study the authors analysed the expression of the most proximal 3' human VH element (VH 6) using a monoclonal antibody (JE-6). VH 6 expression was assessed in various B cell differentiation stages from fetal liver, bone marrow and spleen at 12–20 weeks of gestation. The authors demonstrate that the level of VH 6 expression does not exceed a stochastic usage frequency. This suggests that the localization of VH 6 does not significantly promote its expression during human fetal life, and that other factors must affect the usage of VH genes during human fetal development. 相似文献
144.
145.
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
146.
The authors aimed at evaluating the impact of psychotraumas in psychiatric outpatients. One hundred forty psychiatric outpatients were consecutively included, without distinction of their current pathology. They filled in an inventory of potentially traumatic experiences, a psychological dissociative experiences scale, a somatoform dissociative experiences questionnaire, and underwent a structured interview for diagnosis of posttraumatic stress disorder (according to the DSM-IV). One hundred subjects related psychological trauma, and 76 patients suffered from posttraumatic stress disorder. Dissociative disorders are found significantly correlated with traumatic experience and to posttraumatic stress disorder. The traumatic impact is found more substantial as the number of events was elevated. This study confirms the elevated prevalence of the psychological traumas and psychotraumatic aftermaths in outpatients of a department of psychiatry, independently from the mental disorder. 相似文献
147.
148.
149.
A case-control study of squamous cell carcinoma of the upper aerodigestive tract conducted in Heidelberg and Giessen (FRG) provided information on occupational factors in 200 patients and 800 controls (adjusted to sex, age and area of living; 4:1 matched design). The number of subjects exposed to wood dusts, organic chemicals, coal products or to cement was significantly elevated in the tumour group. An increased risk for head and neck cancer was observed after exposition to wood dust (RR = 2,2), organic compounds (RR = 2,4), coal products (RR = 2,7) and especially to cement (RR = 4,4). The cancer risk due to cement exposition showed a positive correlation to the duration of exposition and remained significantly elevated after adjustment for alcohol and tobacco consumption. 相似文献
150.
L R Bergman 《Acta paediatrica Scandinavica》1991,80(12):1250-1252