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   16037篇
  免费   1181篇
  国内免费   38篇
耳鼻咽喉   159篇
儿科学   492篇
妇产科学   473篇
基础医学   2401篇
口腔科学   299篇
临床医学   2000篇
内科学   2804篇
皮肤病学   446篇
神经病学   1480篇
特种医学   392篇
外科学   1513篇
综合类   122篇
一般理论   38篇
预防医学   1902篇
眼科学   257篇
药学   1150篇
中国医学   26篇
肿瘤学   1302篇
  2023年   150篇
  2022年   334篇
  2021年   571篇
  2020年   289篇
  2019年   514篇
  2018年   540篇
  2017年   377篇
  2016年   472篇
  2015年   464篇
  2014年   641篇
  2013年   831篇
  2012年   1191篇
  2011年   1265篇
  2010年   694篇
  2009年   568篇
  2008年   968篇
  2007年   1020篇
  2006年   965篇
  2005年   894篇
  2004年   788篇
  2003年   703篇
  2002年   661篇
  2001年   154篇
  2000年   145篇
  1999年   137篇
  1998年   130篇
  1997年   100篇
  1996年   86篇
  1995年   74篇
  1994年   93篇
  1993年   70篇
  1992年   102篇
  1991年   97篇
  1990年   82篇
  1989年   80篇
  1988年   83篇
  1987年   59篇
  1986年   60篇
  1985年   62篇
  1984年   55篇
  1983年   47篇
  1982年   40篇
  1981年   49篇
  1980年   50篇
  1979年   44篇
  1978年   41篇
  1977年   36篇
  1976年   37篇
  1974年   39篇
  1973年   34篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
The tibial attachments of the individual anteromedial (AM) and posterolateral (PL) fibre bundles and the entire attachment of the anterior cruciate ligament are described, relating them to consistent bony landmarks; 55 fresh-frozen specimens were measured. The fibre bundles were separated and excised at their attachments and their peripheries marked with a pen. High-resolution scaled digital photographs were taken of each dissected specimen and transferred onto a computer for analysis. A wide variation was found when using the posterior tibial axis, the anterior tibial surface and the medial tibial spine as reference points. The most consistent measurements used the tibial interspinous “over-the-back” ridge as a datum. The attachments of the PL and AM bundles were centred 10 ± 1 mm (mean ± SD) and 17 ± 2 mm anterior to the over-the-back ridge. They were 4 ± 1 and 5 ± 1 mm, respectively, lateral to the medial tibial spine border. The positions of 6 mm circles in the posterior-medial limits of the fibre bundles (representing tunnels in a double-tunnel reconstruction) were measured. The overall dimensions of the tibial plateaux correlated significantly with many measurements. The results from this study could be used to guide ACL reconstruction techniques.  相似文献   
22.
3-Diazo-2-phenylpyrroles 3a-g showed antimicrobial activity against Gram-positive bacteria, whereas against Gram-negative strains the inhibitory activity is limited to derivatives 3a and 3c. The substituents at 4 and 5 positions strongly influence the inhibitory activity, but the presence of the diazo group is crucial for appearance of activity.  相似文献   
23.
The cascade of physiologic mechanisms in response to infection, the acute-phase response, is recognized as playing a major role in host defence. One such response is the hypoferremia that is consistently reported to occur during bacterial infection. This study aimed to determine whether the alterations in plasma iron were conditionable using the conditioned taste aversion (CTA) paradigm. The regime involved the pairing of a novel-tasting saccharin solution with bacterial endotoxin. Seven days after the initial pairing of these stimuli (the test day), the saccharin solution was represented. Animals exposed to this condition displayed a significant reduction in the level of plasma iron. Animals treated with an intraperitoneal dose of 400 μg/Kg lipopolysaccharide (LPS) displayed lower conditioned iron levels than rats infused with 100 μg/Kg LPS; however, this difference was not significant. These results showed that in addition to other acute-phase responses (fever and anorexia), plasma iron alterations are able to be manipulated through behavioral manipulations.  相似文献   
24.
25.
Information on external validity of work site health promotion research is essential to translate research findings to practice. The authors provide a literature review of work site health behavior interventions. Using the RE-AIM framework, they summarize characteristics and results of these studies to document reporting of intervention reach, adoption, implementation, and maintenance. The authors reviewed a total of 24 publications from 11 leading health behavior journals. They found that participation rates among eligible employees were reported in 87.5% of studies; only 25% of studies reported on intervention adoption. Data on characteristics of participants versus nonparticipants were reported in fewer than 10% of studies. Implementation data were reported in 12.5% of the studies. Only 8% of studies reported any type of maintenance data. Stronger emphasis is needed on representativeness of employees, work site settings studied, and longer term results. Examples of how this can be done are provided.  相似文献   
26.
A R Bull 《Public health》1992,106(5):397-399
Medical audit is based on a cyclical model which is ideally suited to operational work that is (1) regularly repeated in similar situations; (2) clearly and directly linked to outcomes; (3) amenable to criteria of quality. The work of public health physicians is both operational (e.g. investigation of outbreaks of communicable disease) and strategic (e.g. health needs assessment). A cyclical model is not appropriate to strategic activity. Evaluation of that activity is essential--but should not be constrained/limited by inappropriate adherence to the audit cycle.  相似文献   
27.
BACKGROUND: To adequately address the complex health needs of young people, their access to services, and the quality of services received, must be improved. AIMS: To explore the barriers to service provision for young people and to identify the training needs of primary healthcare service providers in New South Wales (NSW), Australia. DESIGN OF STUDY: A cross-sectional, qualitative study of the perspectives of a range of health service providers. SETTING: A range of primary healthcare organisations across NSW. METHODS: Samples of general practitioners (GPs), youth health workers, youth health coordinators, and community health centre staff were drawn from urban and rural clusters across NSW. Focus groups and interviews were used to identify barriers to service provision and the training needs of service providers. Data were tape recorded, transcribed, and analysed. RESULTS: Barriers to service provision among GPs and community health centre staff included inadequate time, flexibility, skills, and confidence in working with young people, and poor linkages with other relevant services. Training needs included better knowledge of and skills in adolescent health requirements, working with adolescents, and working with other services. Barriers to service provision for youth health workers and coordinators included lack of financial resources and infrastructure. There were few linkages between groups of service providers. CONCLUSION: Models of service provision that allow stronger linkages between service providers, sufficient time for consultation with young people, adequate training and support of health professionals, and flexibility of service provision, including outreach, should be explored and evaluated.  相似文献   
28.
29.
To determine whether the third-trimester maternal serum concentration of paraxanthine, caffeine's primary metabolite, is associated with delivery of a small-for-gestational age infant (birth weight less than the 10th percentile for gestational age, gender, and ethnicity) and whether this association differs by smoking, the authors studied 2,515 women who participated in the Collaborative Perinatal Project from 1959 to 1966. The women provided a third-trimester serum sample and had been controls for a nested case-control study of spontaneous abortion. The mean serum paraxanthine concentration was greater in women who gave birth to small-for-gestational age infants (754 ng/ml) than to appropriately grown infants (653 ng/ml, p = 0.02). However, the linear trend for increasing serum paraxanthine concentration to be associated with increasing risk of small-for-gestational age birth was confined to women who also smoked (p = 0.03). There was no association between paraxanthine and fetal growth in nonsmokers (p = 0.48). Adjustment for maternal age, pre-pregnant weight, education, parity, ethnicity, and the number of cigarettes smoked per day did not alter the results substantially, although the p value for trend among smokers increased to 0.07. The authors conclude that maternal third-trimester serum paraxanthine concentration, which reflects caffeine consumption, was associated with a higher risk of reduced fetal growth, particularly among women who smoked.  相似文献   
30.
Postoperative Cognitive Dysfunction in Middle-aged Patients   总被引:13,自引:0,他引:13  
Background: Postoperative cognitive dysfunction (POCD) after noncardiac surgery is strongly associated with increasing age in elderly patients; middle-aged patients (aged 40-60 yr) may be expected to have a lower incidence, although subjective complaints are frequent.

Methods: The authors compared the changes in neuropsychological test results at 1 week and 3 months in patients aged 40-60 yr, using a battery of neuropsychological tests, with those of age-matched control subjects using Z-score analysis. They assessed risk factors and associations of POCD with measures of subjective cognitive function, depression, and activities of daily living.

Results: At 7 days, cognitive dysfunction as defined was present in 19.2% (confidence interval [CI], 15.7-23.1) of the patients and in 4.0% (CI, 1.6-8.0) of control subjects (P < 0.001). After 3 months, the incidence was 6.2% (CI, 4.1-8.9) in patients and 4.1% (CI, 1.7-8.4) in control subjects (not significant). POCD at 7 days was associated with supplementary epidural analgesia and reported avoidance of alcohol consumption. At 3 months, 29% of patients had subjective symptoms of POCD, and this finding was associated with depression. Early POCD was associated with reports of lower activity scores at 3 months.  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