全文获取类型
收费全文 | 10148篇 |
免费 | 659篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 51篇 |
儿科学 | 397篇 |
妇产科学 | 251篇 |
基础医学 | 1118篇 |
口腔科学 | 472篇 |
临床医学 | 1072篇 |
内科学 | 1958篇 |
皮肤病学 | 120篇 |
神经病学 | 846篇 |
特种医学 | 662篇 |
外科学 | 1322篇 |
综合类 | 388篇 |
一般理论 | 11篇 |
预防医学 | 994篇 |
眼科学 | 190篇 |
药学 | 527篇 |
1篇 | |
中国医学 | 4篇 |
肿瘤学 | 452篇 |
出版年
2021年 | 142篇 |
2020年 | 69篇 |
2019年 | 129篇 |
2018年 | 148篇 |
2017年 | 124篇 |
2016年 | 131篇 |
2015年 | 159篇 |
2014年 | 195篇 |
2013年 | 329篇 |
2012年 | 416篇 |
2011年 | 438篇 |
2010年 | 270篇 |
2009年 | 281篇 |
2008年 | 389篇 |
2007年 | 443篇 |
2006年 | 425篇 |
2005年 | 412篇 |
2004年 | 384篇 |
2003年 | 355篇 |
2002年 | 360篇 |
2001年 | 298篇 |
2000年 | 298篇 |
1999年 | 282篇 |
1998年 | 190篇 |
1997年 | 198篇 |
1996年 | 184篇 |
1995年 | 140篇 |
1994年 | 153篇 |
1993年 | 162篇 |
1992年 | 236篇 |
1991年 | 231篇 |
1990年 | 248篇 |
1989年 | 228篇 |
1988年 | 241篇 |
1987年 | 232篇 |
1986年 | 213篇 |
1985年 | 217篇 |
1984年 | 111篇 |
1983年 | 110篇 |
1982年 | 84篇 |
1981年 | 98篇 |
1980年 | 75篇 |
1979年 | 90篇 |
1978年 | 87篇 |
1977年 | 74篇 |
1976年 | 67篇 |
1975年 | 52篇 |
1974年 | 59篇 |
1972年 | 59篇 |
1971年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
1.
2.
3.
Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight. 相似文献
4.
5.
6.
Surgical treatment of displaced olecranon fractures by tension band wiring technique 总被引:2,自引:0,他引:2
G Wolfgang F Burke D Bush J Parenti J Perry B LaFollette S Lillmars 《Clinical orthopaedics and related research》1987,(224):192-204
Forty-five displaced olecranon fractures including 14 accompanying dislocated radial heads and seven radial head fractures were treated over a 13-year period by the tension band wiring technique. The use of supplemental internal fixation when necessary allows excellent results with the use of this technique, even in the presence of severe comminution or radial head dislocation. Primary silicone radial head implants fractured in all three patients in which they were used, necessitating repeat surgery in two patients to date. While loss of motion in terminal extension was a common aftermath of displaced olecranon fracture (59%), it was usually minor and functionally insignificant. True Kirschner-wire migration was not a common problem and can probably be eliminated by proper technique. The presence of gaps in the intraarticular surface of the semilunar notch of the ulna produced no ill effects and was compatible with excellent results. If only those cases with isolated olecranon fractures in this series are considered, there were good and excellent results in 29 of 30 cases (97%). Excision of the olecranon fragment(s) should be reserved for those cases when anatomic restoration cannot be achieved with internal fixation. 相似文献
7.
Greg Guest Laura Johnson Holly Burke Reathe Rain-Taljaard Lawrence Severy Claire von Mollendorf Lut Van Damme 《AIDS education and prevention》2007,19(4):310-320
If proven effective, vaginal microbicides and diaphragms will likely be part of a larger HIV prevention model that includes condoms and other prevention strategies. It is, therefore, important to understand how introducing new prevention methods may affect overall patterns of sexual risk behavior. Data presented were collected as part of a safety and feasibility study of ACIDFORM gel with a diaphragm among 120 women in South Africa. Interviews were administered at enrollment and months 1, 3, 5, and 6 of the trial. Focus groups were conducted at trial exit. Frequency of sex increased significantly after enrollment. This increase appears to be owing to perceived protection from HIV and greater sexual pleasure afforded by the gel. Male condom use was high overall but increased significantly from enrollment. Data suggest this is because of increased partner involvement, increased negotiating power afforded by study participation, and provision of free condoms perceived to be of high quality. 相似文献
8.
9.
M Burke 《Hospitals》1991,65(15):38-40
Health care professionals and election analysts agree that health care will be a bigger issue in the 1992 election than it was in 1988. Among the reasons: Some prominent members of Congress are active in health care issues, media coverage of health insurance problems is growing, and several major health care reform bills have been introduced in Congress. 相似文献
10.
Six children developed seven cases of ulna neuropathy between 7 days and 6 years after significant elbow injury. None had evidence of acute nerve damage at the time of initial trauma. This complication, which develops soon after injury, has not been well documented. For this reason, the mode of presentation, treatment options, and review of the literature is presented. 相似文献