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   1856篇
  免费   130篇
  国内免费   25篇
耳鼻咽喉   6篇
儿科学   63篇
妇产科学   10篇
基础医学   140篇
口腔科学   77篇
临床医学   153篇
内科学   411篇
皮肤病学   25篇
神经病学   203篇
特种医学   278篇
外科学   210篇
综合类   30篇
一般理论   14篇
预防医学   190篇
眼科学   39篇
药学   82篇
  2篇
肿瘤学   78篇
  2021年   12篇
  2019年   12篇
  2018年   33篇
  2017年   14篇
  2016年   13篇
  2015年   16篇
  2014年   25篇
  2013年   41篇
  2012年   57篇
  2011年   57篇
  2010年   50篇
  2009年   41篇
  2008年   55篇
  2007年   68篇
  2006年   62篇
  2005年   65篇
  2004年   63篇
  2003年   36篇
  2002年   42篇
  2001年   56篇
  2000年   69篇
  1999年   80篇
  1998年   71篇
  1997年   50篇
  1996年   46篇
  1995年   42篇
  1994年   41篇
  1993年   44篇
  1992年   47篇
  1991年   46篇
  1990年   36篇
  1989年   65篇
  1988年   45篇
  1987年   55篇
  1986年   56篇
  1985年   57篇
  1984年   38篇
  1983年   35篇
  1981年   19篇
  1980年   24篇
  1979年   33篇
  1978年   13篇
  1977年   29篇
  1976年   26篇
  1975年   11篇
  1973年   16篇
  1972年   14篇
  1971年   12篇
  1969年   9篇
  1968年   12篇
排序方式: 共有2011条查询结果,搜索用时 15 毫秒
61.
Factors associated with gay male couples' concordance on aspects of sexual agreements remain understudied. The present study examined which relationship factors, self-reports of UAI, and patterns of HIV testing may be associated with men who were concordant about having a sexual agreement, the same type of sexual agreement, and adhering to their sexual agreement with their main partner. Various recruitment strategies were used to collect dyadic data from 142 gay male couples. Concordance on aspects of sexual agreements varied within the sample. Results indicated that relationship satisfaction was significantly associated with couples who were concordant about having and adhering to their sexual agreement. Predictability and faith of trusting a partner, and value in one's sexual agreement were also positively associated with couples' adhering to their sexual agreement. More research is needed to better understand how relationship dynamics, including sexual agreements, affect HIV risk among gay male couples in the U.S.  相似文献   
62.
63.
牛津膝置换是使用最广泛的膝关节单髁置换(UKR)。牛津膝在37年前开始应用,拥有一个全匹配的活动衬垫,因而磨损率非常低。牛津膝最主要的使用指征是膝关节前内侧骨关节炎,这种病人至少占所有需要行膝关节置换术患者的50%。由于这一系统的设计特点,传统UKR的反指征,如年龄、活动量、肥胖、髌股关节损害和软骨钙质沉着症等对于牛津膝均不是反指征。与全膝关节置换(TKR)相比,牛津膝提供更快的康复、更好的功能、更大的活动度和更好的术后满意度,发生并发症更少、程度更轻,病残率和死亡率更低。一个持续超过30年的研究显示在90%的病例中,牛津膝为患者终生提供了优或良的临床结果,且不需要翻修。在最近15年,牛津膝通过微创手术入路植入,涉及6000多例使用该入路牛津膝置换的9个研究报道显示,10年生存率约95%。在许多这样的研究中,医生们在拟行膝关节置换的患者中约50%使用了牛津单髁膝置换。  相似文献   
64.
A 48-year-old African-American woman with both sickle cell anemia and chronic pain was treated with a hydrophobic angiotensin I-converting enzyme (ACE) inhibitor. This resulted in the complete resolution of her pain. When the ACE inhibitor was deliberately stopped, her pain recurred, only to cease again after the ACE inhibitor was deliberately resumed. The activation of ACE may be an early step in the arterial vaso-occlusion typical of sickle cell disease.  相似文献   
65.
66.
The relationship between the force generated by an isometrically contracting muscle and the associated myoelectric signal has been the subject of extensive investigation in the past and conflicting results were reported regarding this relationship. The objective of the present study was to investigate some of the sources that may lead to such conflicting results. Two possible sources were examined. The first was the variability in the force-EMG relationship resulting from processing the EMG signal with different EMG signal processing techniques and the second was the variability in the force-EMG relation obtained from repeated muscle contractions. The results of the study indicate that slight variations in the force-EMG relationships can be attributed to the selection of different processing techniques. However, the variability in the force-EMG relation, obtained by using different EMG signal processors, was found to be significantly smaller than the variability in this relationship obtained from repeated muscle contractions.  相似文献   
67.
68.
OBJECTIVE: To use the Minimum Data Set (MDS) to derive a risk-adjustment model for pressure ulcer development that may be used in assessing the quality of nursing home care. DESIGN: Perspective observational study using MDS data from 1997. SETTING: A large, for-profit, nursing home chain. PARTICIPANTS: Our unit of analysis was 39,649 observations made on 14,607 nursing home residents who were without a stage 2 or larger pressure ulcer on an index assessment. MEASUREMENTS: Pressure ulcer status was determined at an outcome assessment approximately 90 days after an index assessment. Potential predictors of pressure ulcer development were examined for bivariate associations, contributing to the development of a multivariate logistic regression model. RESULTS: A stage 2 or larger pressure ulcer developed in 2.3% of the observations. Seventeen resident characteristics were found to be associated with pressure ulcer development. These included dependence in mobility and transferring, diabetes mellitus, peripheral vascular disease, urinary incontinence, lower body mass index, and end-stage disease. A risk-adjustment model based on these characteristics was well calibrated and able to discriminate among residents with different levels of risk for ulcer development (model c-statistic = 0.73). CONCLUSION: A clinically credible risk-adjustment model with good performance properties can be developed using the MDS. This model may be useful in profiling nursing homes on their rate of pressure ulcer development.  相似文献   
69.
70.
Gauwerky  C; Golde  DW 《Blood》1980,56(5):886-891
We have investigated the hormonal responsiveness of K562 cells using a serum-substituted in vitro clonogenic assay. Dexamethasone inhibited colony formation by the K562 cells, and the inhibitory effect could be reversed by progesterone (10(-6) M). Fluoxymesterone caused a prominent enhancement of K562 colony growth, whereas estriol had no effect. Stimulation by triiodothyronine was maximal at 10(-7) M, and the thyroid effect could be abrogated by the beta 2-adrenergic antagonist butoxamine in equimolar concentrations. Using standard tissue culture conditions, the beta-adrenergic agent isoproterenol, but not the alpha catecholamine phenylephrine, enhanced the proliferation of K562 cells. When K562 cells were grown under hormone-depleted conditions, they developed responsiveness to phenylephrine and were no longer stimulated by isoproterenol. DbcAMP and prostaglandins of the E series also caused K562 colony enhancement. Prostaglandin F2 alpha had no effect on cell proliferation. Insulin was an effective stimulant of colony formation of K562 cells, as were human growth hormone and ovine prolacin. Bovine growth hormone had no effect. Our results are consistent with the identificaiton of K562 as an erythroid line, and they indicate that K562 cells respond to endocrine hormones in a manner analogous to normal erythroid progenitors.  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