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   31994篇
  免费   1809篇
  国内免费   99篇
耳鼻咽喉   255篇
儿科学   1099篇
妇产科学   923篇
基础医学   3624篇
口腔科学   400篇
临床医学   5853篇
内科学   5327篇
皮肤病学   346篇
神经病学   3132篇
特种医学   602篇
外国民族医学   1篇
外科学   3028篇
综合类   312篇
现状与发展   1篇
一般理论   50篇
预防医学   4482篇
眼科学   446篇
药学   1853篇
中国医学   34篇
肿瘤学   2134篇
  2023年   192篇
  2022年   327篇
  2021年   591篇
  2020年   421篇
  2019年   656篇
  2018年   808篇
  2017年   561篇
  2016年   633篇
  2015年   673篇
  2014年   988篇
  2013年   1593篇
  2012年   2304篇
  2011年   2429篇
  2010年   1283篇
  2009年   1129篇
  2008年   2187篇
  2007年   2387篇
  2006年   2275篇
  2005年   2209篇
  2004年   2032篇
  2003年   1961篇
  2002年   1872篇
  2001年   224篇
  2000年   185篇
  1999年   286篇
  1998年   373篇
  1997年   312篇
  1996年   246篇
  1995年   275篇
  1994年   214篇
  1993年   216篇
  1992年   136篇
  1991年   139篇
  1990年   139篇
  1989年   116篇
  1988年   110篇
  1987年   97篇
  1986年   94篇
  1985年   106篇
  1984年   125篇
  1983年   127篇
  1982年   149篇
  1981年   142篇
  1980年   120篇
  1979年   58篇
  1978年   72篇
  1977年   62篇
  1976年   50篇
  1975年   40篇
  1974年   43篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Childbearing women and infants in developing countries continue to experience unacceptably high rates of mortality and morbidity in spite of targeted initiatives to address the problem. The aim of this study was to identify the beliefs and rituals of traditional birth attendants (TBAs) in one indigenous Guatemalan community to better understand the cultural influences on perinatal care practices. Ethnographic methods were used to increase understanding of the practice of 10 Mayan TBAs. Three themes were constructed: sacred calling, sacred knowledge and sacred ritual.  相似文献   
22.
The use of epidemiologic research designs and analytical methods is common in dietetics research. Food and nutrition professionals who seek to perform evidence-based practice or participate in research design, analysis, and communication need skills in the essentials of epidemiology. This is one of a series of monographs on research methodology that addresses these needs and supports the goals of the Board of Editors of the Journal of the American Dietetic Association to further enhance competency and skills. This monograph focuses on statistical approaches for univariate analyses used with the primary observational study designs associated with epidemiology. Tables illustrating the presentation and interpretation of these results are included.  相似文献   
23.
OBJECTIVE: The purpose of this study was to compare learning of a functional living skill in two contexts for individuals with long-term schizophrenia. METHOD: Forty-four people with schizophrenia were matched on cognitive level. One of each pair was randomly designated to either a clinic or home cooking group, with the other assigned to the remaining group. Cooking skill was assessed using the Kitchen Task Assessment-Modified (KTA-M) both before and after the intervention. Learning for each group was analyzed using t tests. A multiple regression analysis to control for baseline differences was used to compare the learning of the two groups. RESULTS: Participants in both groups scored significantly higher on the KTA-M after cooking lessons (t = 5.57, df = 21, p < .0001--clinic; t = 7.81. df = 21, p < .0002--home) reflecting learning of cooking skill; there was no statistically significant difference in scores on the KTA-M between the two groups based on where the learning took place (beta = -1.8, df = 42, p < 0.23). Qualitative differences between the learning environments provide suggestions for teaching functional living skills to this population. CONCLUSIONS: Learning new skills in the home was not better than learning in the clinic for people with schizophrenia in this study. Further research on the effect of context on learning for people with cognitive dysfunction and schizophrenia is recommended.  相似文献   
24.
BACKGROUND: To ascertain survival of ischemic advanced heart failure patients by treatment allocation, we examined the outcome of transplant assessment patients allocated to medical therapy, high-risk conventional surgery, or transplantation. METHODS: Patients were identified from the Papworth transplant database and excluded if primary etiology was not ischemic. Grouping was undertaken according to treatment allocation at initial assessment, and analysis was performed by intention to treat. Survival was computed from the time of assessment and Cox regression used to stratify patients according risk with the Heart Failure Survival Score. RESULTS: From May 1993 to September 2001, a total of 755 patients were admitted for transplant assessment, with 348 (46.1%) identified as having heart failure of ischemic origin. Variables required for calculation of the Heart Failure Survival Score was available in 273 patients (78.4%), and 20 patients (7.3%) were lost to follow-up. Of the remaining 253 patients, 89 (35.2%) were allocated to medical therapy, 32 (12.6%) to surgery, and 132 (52.2%) to transplantation. The relative risk (95% confidence limit) of death compared with medical therapy was 0.62 (0.28, 1.40) for surgery and 0.38 (0.24, 0.61) for transplantation in medium- to high-risk patients. For low-risk patients, the relative risks for death compared with medical therapy were 1.87 (0.63, 5.60) for surgery and 1.97 (0.79, 4.96) for transplantation. CONCLUSIONS: Transplantation improved survival of medium- and high-risk patients compared with medical therapy. In the low-risk group, this was not evident. However, repeated assessment of risk is required because the hazard for death rises steadily after the third year in these patients.  相似文献   
25.
PURPOSE: Currently, no drug treatment is available for strengthening underacting extraocular muscles (EOM) in strabismus. We showed previously that single injections of insulin-like growth factor (IGF-1) result in significant but short-term increases in muscle force generation. This study examined the effects of sustained release of IGF-1 on force generation in rabbit superior rectus muscles. METHODS: In adult rabbits, slow-release pellets containing IGF-1 were implanted on the global side of one superior rectus muscle. After 1 week, or 1, 2, 3, or 6 months, treated and control muscles were examined for force generation using an in vitro physiology apparatus. All muscles were prepared for histology and mean myofiber cross-sectional areas were determined. RESULTS: One and 3 months after pellet implantation, treated muscles generated significantly greater force than contralateral control muscles, whereas at 2 months, no significant difference was found. Force per cross-sectional area (mN/cm(2)) at 3 months also increased significantly in the treated muscles. Mean muscle cross-sectional area increased significantly after 1, 2, and 3 months of sustained exposure to IGF-1 compared with controls. After an additional 3 months without IGF-1 exposure, mean cross-sectional areas were significantly greater than controls but significantly reduced compared with areas at 1, 2, and 3 months. CONCLUSIONS: IGF-1 appears to be highly effective in increasing muscle force generation. Because slow release of IGF-1 results in sustained increases in EOM force generation, it may be a potentially useful alternative to surgical resection procedures because it avoids many of the potential long-term biomechanical hazards of resection surgery.  相似文献   
26.
Naloxone, an opioid peptide antagonist, has been reported to facilitate voiding in neurologic bladder disorders, but its effects on the neural micturition reflex arc are poorly understood. We studied the effect of naloxone in 34 male adult cats, spinalized at C5-C6 level 7 to 119 days previously. Each cat served as its own control. The following tests were performed: Urethral pressure profiles, cystosphincterograms with the urethro-vesical junction opened and closed and mechanograms of the detrusor, and the circular and longitudinal urethral muscles. The study included (1) the effects of anesthesia of the bladder and pelvic nerve, as well as that of the urethral and pudendal nerves; (2) the action of naloxone; and (3) the action of oxymorphone. Our results demonstrated that naloxone (1) increased somatic (osteotendinous and nociceptive) reflexes and aggravated spasticity; (2) increased vegetative micturitional and sexual reflexes, in particular the urethra-urethral contraction reflex, aggravating the spasmodic contractions of the external sphincter; and (3) increased the frequency and intensity of the mass reflex. In consequence, we suggest that naloxone is contraindicated in cases of spinal cord lesions with detrusor-sphincter dyssynergia syndrome.  相似文献   
27.
28.
29.
30.
Faced with a rapidly changing market, increased legislation and intense competition, mental health service providers must be sophisticated planners and position themselves advantageously in the marketplace. They can effectively position themselves to be profitable and sustaining through market segmentation and sensitivity. The following article will address one concept of marketing that has received less attention but is of critical importance: positioning. As the market environment becomes increasingly competitive, positioning will be the key to success for mental health programs and institutions. LINDA A. LENNOX, M.S.N., CMHA, has extensive experience in mental health administration. She currently resides in the Washington, DC area. DAVID AMBROSE, D.B.A., is the Lucas Professor of Business Administration, University of Nebraska at Omaha, Omaha, NE.  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