全文获取类型
收费全文 | 1254篇 |
免费 | 101篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 39篇 |
妇产科学 | 17篇 |
基础医学 | 172篇 |
口腔科学 | 56篇 |
临床医学 | 163篇 |
内科学 | 229篇 |
皮肤病学 | 30篇 |
神经病学 | 67篇 |
特种医学 | 188篇 |
外科学 | 129篇 |
综合类 | 68篇 |
一般理论 | 1篇 |
预防医学 | 71篇 |
眼科学 | 20篇 |
药学 | 58篇 |
中国医学 | 1篇 |
肿瘤学 | 43篇 |
出版年
2022年 | 7篇 |
2021年 | 18篇 |
2020年 | 7篇 |
2019年 | 17篇 |
2018年 | 21篇 |
2017年 | 11篇 |
2016年 | 15篇 |
2015年 | 26篇 |
2014年 | 18篇 |
2013年 | 31篇 |
2012年 | 34篇 |
2011年 | 46篇 |
2010年 | 32篇 |
2009年 | 38篇 |
2008年 | 44篇 |
2007年 | 39篇 |
2006年 | 49篇 |
2005年 | 47篇 |
2004年 | 35篇 |
2003年 | 43篇 |
2002年 | 50篇 |
2001年 | 33篇 |
2000年 | 36篇 |
1999年 | 36篇 |
1998年 | 35篇 |
1997年 | 51篇 |
1996年 | 38篇 |
1995年 | 26篇 |
1994年 | 17篇 |
1993年 | 15篇 |
1992年 | 30篇 |
1991年 | 25篇 |
1990年 | 24篇 |
1989年 | 22篇 |
1988年 | 29篇 |
1987年 | 36篇 |
1986年 | 30篇 |
1985年 | 35篇 |
1984年 | 22篇 |
1983年 | 18篇 |
1982年 | 17篇 |
1981年 | 19篇 |
1980年 | 21篇 |
1979年 | 15篇 |
1978年 | 16篇 |
1977年 | 12篇 |
1976年 | 11篇 |
1972年 | 7篇 |
1970年 | 6篇 |
1967年 | 12篇 |
排序方式: 共有1361条查询结果,搜索用时 31 毫秒
1.
Christine D Pollard Susan M Sigward Susumu Ota Karen Langford Christopher M Powers 《Clinical journal of sport medicine》2006,16(3):223-227
OBJECTIVE: To examine the influence of in-season injury prevention training on hip and knee kinematics during a landing task. DESIGN: Longitudinal pre-post intervention study. SETTING: Testing sessions were conducted in a biomechanics research laboratory. PARTICIPANTS: Eighteen female soccer players between the ages of 14 and 17 participated in this study. All subjects were healthy with no current complaints of lower extremity injury. INTERVENTIONS: Testing sessions were conducted prior to and following a season of soccer practice combined with injury prevention training. MAIN OUTCOME MEASUREMENTS: During each testing session three-dimensional kinematics were collected while each subject performed a drop landing task. Peak hip and knee joint angles were measured during the early deceleration phase of landing and compared between pre- and post-training using paired t-tests. RESULTS: Following a season of soccer practice combined with injury prevention training, females demonstrated significantly less hip internal rotation (7.1 degrees vs. 1.9 degrees; P = 0.01) and significantly greater hip abduction (-4.9 degrees vs. -7.7 degrees; P = 0.02). No differences in knee valgus or knee flexion angles were found post-season. CONCLUSIONS: Female soccer players exhibited significant changes in hip kinematics during a landing task following in-season injury prevention training. Our results support the premise that a season of soccer practice combined with injury prevention training is effective in altering lower extremity motions that may play a role in predisposing females to ACL injury. 相似文献
2.
3.
4.
5.
6.
7.
Intraobserver and interobserver variation in the sonographic grading of placental maturity. 总被引:4,自引:0,他引:4
OBJECTIVES: The appearance of Grannum Grade III changes in the placenta at around 34-36 weeks is a predictor of adverse perinatal outcome, which may be reduced by reporting to the clinician. This has led to the suggestion that the placental grade should be noted during any third-trimester scan. There are no published data on the reproducibility of sonographic Grannum grading of the placenta; the objective of this study was to evaluate intra- and interobserver variation. METHODS: Fifty-five placental images from normal and complicated pregnancies of several different gestational ages were collected between April and October 2001. Three fetal medicine consultants and three experienced sonographers graded the images as 0, I, II, III or ungradeable. They then regraded the same images, presented in a different order and with different codes, 4-6 weeks later. Observers were blinded to their previous grading and to each others'. Weighted kappa (kappa), with linear weights, was used to look for strength of agreement. RESULTS: There was good agreement between the two observations of each placental image for five observers (kappa = 0.61 to 0.90), and moderate agreement for one observer (kappa = 0.56). However, the kappa-values for comparisons between the 15 pairs of observers ranged from 0.24 to 0.69 with six values below 0.41, indicating only fair agreement. This was confirmed by the overall kappa-value of 0.24 between all six observers. The agreement between the observers for Grade III placenta was poor, with an overall kappa-value of 0.09. CONCLUSIONS: Although intraobserver agreement was generally good, interobserver agreement was only fair for all grades and poor for Grade III placenta. This may be an indication that Grannum grading is not reproducible or it may reflect a need for training in those performing grading. Such variation may limit the effectiveness of reporting Grannum grades in clinical practice. 相似文献
8.
Bachelor's and master's degrees in EMS are not yet commonplace, but with each year, they are becoming more important. A degree in EMS can provide not only the essentials of good paramedic skills, but also a knowledge of biology, anatomy and physiology, advanced chemistry and EMS management. Dwight Polk and Stuart Langford discuss the current status of bachelor's and master's degree programs in EMS and talk to people who have gone far in their chosen careers because they have such a degree. 相似文献
9.
Deletion of the ferric uptake regulator Fur impairs the in vitro growth and virulence of Actinobacillus pleuropneumoniae 下载免费PDF全文
Jacobsen I Gerstenberger J Gruber AD Bossé JT Langford PR Hennig-Pauka I Meens J Gerlach GF 《Infection and immunity》2005,73(6):3740-3744
In order to investigate the role of the ferric uptake regulator Fur in the porcine lung pathogen Actinobacillus pleuropneumoniae, we constructed an isogenic in-frame deletion mutant, A. pleuropneumoniae Deltafur. This mutant showed constitutive expression of transferrin-binding proteins, growth deficiencies in vitro, and reduced virulence in an aerosol infection model. 相似文献
10.
Cholecystokinin-decreased food intake in rhesus monkeys 总被引:1,自引:0,他引:1