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   7299篇
  免费   1096篇
  国内免费   23篇
耳鼻咽喉   49篇
儿科学   367篇
妇产科学   156篇
基础医学   1045篇
口腔科学   178篇
临床医学   1004篇
内科学   1301篇
皮肤病学   75篇
神经病学   773篇
特种医学   638篇
外国民族医学   1篇
外科学   751篇
综合类   472篇
一般理论   3篇
预防医学   510篇
眼科学   126篇
药学   633篇
中国医学   5篇
肿瘤学   331篇
  2021年   78篇
  2020年   52篇
  2019年   82篇
  2018年   117篇
  2017年   80篇
  2016年   88篇
  2015年   120篇
  2014年   158篇
  2013年   229篇
  2012年   277篇
  2011年   293篇
  2010年   201篇
  2009年   169篇
  2008年   246篇
  2007年   255篇
  2006年   273篇
  2005年   288篇
  2004年   256篇
  2003年   250篇
  2002年   259篇
  2001年   215篇
  2000年   233篇
  1999年   219篇
  1998年   208篇
  1997年   166篇
  1996年   188篇
  1995年   154篇
  1994年   126篇
  1993年   133篇
  1992年   169篇
  1991年   181篇
  1990年   140篇
  1989年   202篇
  1988年   161篇
  1987年   220篇
  1986年   176篇
  1985年   176篇
  1984年   138篇
  1983年   134篇
  1982年   114篇
  1981年   106篇
  1980年   134篇
  1979年   115篇
  1978年   80篇
  1977年   83篇
  1976年   74篇
  1975年   77篇
  1974年   67篇
  1972年   66篇
  1971年   49篇
排序方式: 共有8418条查询结果,搜索用时 233 毫秒
1.
2.
It is often difficult for medical professionals to understand the behaviour of people with diabetic foot syndrome. We describe the different psychological factors that play a role in the maintenance of intermittent implementation of medical recommendations. In particular we look at the consequences of neuropathy and of the recommendation to offload pressure, as well as the contradictions between the realities of the patient and the medical professionals involved in their care. We show that the solutions that patients develop are based on normal psychological processes and we encourage professionals to consider these aspects in their relationship to people with DFS and when developing individualised preventative measures.  相似文献   
3.
Numerous surveys at the national and regional level have demonstrated that large inequalities in infant health status exist in Southern Africa. Few studies have assessed infant mortality at the intra-urban scale of geographic analysis. Comparisons between infant mortality rates from different areas are made even more meaningful if the data are divided into two primary categories based on period-of-death; these being the neonatal and post-neonatal components. This study presents the results of a survey undertaken in Metropolitan Cape Town (population 1.6 million) during 1982. The aim was to determine the spatial variation of neonatal and post-neonatal mortality at the suburb (or community) level within the city. Overall, a total of 36,789 live births and 928 infant deaths were recorded; 53.4% in the neonatal period and 46.6% in the post-neonatal period. The mean infant mortality rate was 25.2 per 1000 live births; the neonatal mortality rate and post-neonatal mortality rate being 13.5/1000 and 11.7/1000, respectively. A marked range in death rates was evident for both components. For the neonatal category it was 0.0-49.9/1000 and 0.0-40.0/1000 for the post-neonatal period. The generally low post-neonatal mortality rate among the 69 suburbs studied has made the neonatal component the dominant contributor to the infant mortality rate. However, in the lowest socio-economic areas the post-neonatal mortality rate was responsible for over 60% of infant deaths.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
4.
5.
A prospective blinded study was performed on 191 high-risk patients with pregnancies ranging from 25 to 42 weeks gestation to investigate the value of a single Doppler analysis of the umbilical artery blood flow waveform (systolic-to-diastolic ratio, S/D) for predicting poor perinatal outcome. This was defined as the presence of heavy meconium, delivery of a growth-retarded infant, an umbilical cord arterial pH less than 7.2, or a 5-minute Apgar score less than 7. The interval between Doppler examination and delivery ranged from 12 hours to 15 weeks. No clinical data were available to the examiner performing the Doppler study. Moreover, the Doppler measurements were unknown to the attending physicians. The sensitivity, specificity, and positive and negative predictive values of the Doppler study in predicting outcome were 30.4%, 92.9%, 36.8%, and 92.6%, respectively, with an adverse outcome prevalence of 12%. These results indicate that a single random S/D ratio from the umbilical artery is not an adequate screening test for the risk of perinatal complications.  相似文献   
6.
BACKGROUND: Our aims in the present study were to estimate the influences of pain and urinary symptoms on quality of life, and to determine which of these two variables has the most predictive power with respect to quality of life in young men with chronic prostatitis-like symptoms. METHODS: Chronic prostatitis-like symptoms were measured by the National Institutes of Health-Chronic Prostatitis Symptom Index. Of the 28,841 men aged 20 years who lived in the study community, 18,495 men (a response rate 64.1%) agreed to participate in the study. A total of 1057 men who complained of symptoms indicative of chronic prostatitis were included in the study. The influences of pain and urinary symptoms on quality of life were determined using logistic regression analysis. The receiver operating characteristic (ROC) curve was used to estimate the predictive ability of each of these variables with respect to quality of life. RESULTS: Results from multivariate analysis showed that both pain and urinary symptoms were associated with an increased likelihood of impaired quality of life, although pain contributed more to a reduced quality of life than urinary symptoms. Relative to men who experienced mild pain, men who experienced moderate pain had a 3.9-fold risk of poor quality of life (odds ratio [OR], 3.87; 95% confidence interval [CI], 2.86-5.23; P < 0.001) and those who experienced severe pain had a 15.7-fold risk of reduced quality of life (OR, 15.68; 95% CI, 6.59-37.35; P < 0.001). Moderate urinary symptoms were associated with a 1.4-fold risk of bother (OR, 1.41; 95% CI, 1.01-1.99; P < 0.001) and severe urinary symptoms were associated with 2.4-fold risk (OR, 2.39; 95% CI, 1.37-4.12; P < 0.001), relative to mild urinary symptoms. Comparison of the effects of pain and urinary symptoms showed that pain severity had the most predictive power for bother, quality of life, and quality-of-life impact. The areas under the ROC curves for bother, quality of life, and quality-of-life impact were 71.3%, 69.3% and 72.5%, respectively. CONCLUSION: Urinary symptoms and pain might be associated with an increased likelihood of impaired quality of life in young men with chronic prostatitis-like symptoms. In addition, our findings suggest that pain severity is the most influential variable for determining quality of life in this population.  相似文献   
7.
8.
9.
A series of 1-[1-arylcyclohexyl]-1,2,3,6-tetrahydropyridines were prepared by the reaction between 1-(1-cyanocyclohexyl)-1,2,3,6-tetrahydropyridine (1) and an appropriately substituted Grignard reagent. The resulting compounds were tested for their phencyclidine binding site affinities. Selected compounds were then tested for their ability to produce ketamine appropriate responding in monkeys and/or to show neuroprotective effects in a baby rat hypoxia/ischemia model. While it was found that binding site affinity correlated well with discriminative stimulus effects, it was found to be a poor indicator of neuroprotective efficacy within this series.  相似文献   
10.
Surgically-assisted maxillary expansion   总被引:3,自引:0,他引:3  
A combined surgical and orthodontic technique for management of transverse maxillary deficiencies in mature patients is described and discussed. Special references are made to the surgical release of several circummaxillary articulations to facilitate the use of a fixed expansion device, and to the authors' addition of an osteotomy below the nasal spine, to ensure that the nasal septum remains independent of the maxillary segments. Indications for the use of this surgically-assisted maxillary expansion technique, and its advantages when compared with segmented surgical expansion, are also presented.  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