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   13172篇
  免费   872篇
  国内免费   39篇
耳鼻咽喉   87篇
儿科学   321篇
妇产科学   246篇
基础医学   1807篇
口腔科学   495篇
临床医学   1422篇
内科学   3037篇
皮肤病学   200篇
神经病学   1215篇
特种医学   384篇
外科学   1706篇
综合类   65篇
一般理论   5篇
预防医学   1167篇
眼科学   157篇
药学   871篇
中国医学   10篇
肿瘤学   888篇
  2023年   140篇
  2022年   122篇
  2021年   267篇
  2020年   229篇
  2019年   229篇
  2018年   420篇
  2017年   332篇
  2016年   436篇
  2015年   390篇
  2014年   427篇
  2013年   690篇
  2012年   868篇
  2011年   906篇
  2010年   445篇
  2009年   428篇
  2008年   834篇
  2007年   843篇
  2006年   770篇
  2005年   752篇
  2004年   669篇
  2003年   628篇
  2002年   601篇
  2001年   200篇
  2000年   252篇
  1999年   198篇
  1998年   55篇
  1997年   51篇
  1995年   41篇
  1994年   36篇
  1992年   145篇
  1991年   117篇
  1990年   112篇
  1989年   101篇
  1988年   121篇
  1987年   83篇
  1986年   110篇
  1985年   111篇
  1984年   96篇
  1983年   79篇
  1982年   53篇
  1981年   36篇
  1980年   39篇
  1979年   67篇
  1978年   37篇
  1977年   34篇
  1976年   34篇
  1974年   38篇
  1973年   49篇
  1972年   34篇
  1970年   35篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
The results of routine screening for intestinal parasites in 1377 refugees and asylum seekers within 2 weeks of arrival in Sweden showed that protozoa, mainly Giardia intestinalis, were found in 235/1377 (17%) and helminths, mainly hookworms, in 264/1377 (19%). Intestinal parasites were more frequently recovered in refugees coming from South East Asia, Africa and Latin America (infection rates 48%, 43% and 42%, respectively) than in those from Eastern Europe (22%) and the Middle East (32%). Refugees who reported gastrointestinal symptoms were less often infected than those without symptoms (p < 0.001). Of the European refugees, 127 came from Bosnia. A high rate of hookworms was found in this group (15%), suggesting that hookworms may also be transmitted in temperate areas under special conditions. We thus identified relatively high rates of pathogens in all groups of refugees. Screening may therefore be recommended, though more for the benefit of refugees than for the prevention of further spread of the infections.  相似文献   
952.
The aim of this study was to evaluate the fibrinogen enzymatic conversion in blood collected postoperatively from a surgical wound. Ten otherwise healthy patients (aged 11-28 years) in need of surgical treatment for thoracic scoliosis were included in the study. Arterial blood preoperatively and at wound closure were compared with samples of drained blood from the wound at closure and from a collection system for autologous transfusion 2.8 +/- 1.1 h later. There was a decrease in the fibrinogen content in arterial blood from 2.17 +/- 0.35 g/l to 1.23 +/- 0.42 g/l, which followed a 40% haemodilution estimated from the blood loss of 1.6 +/- 0.9 l during the operation. Drained blood contained high concentrations of D-dimer (85 +/- 53 mg/l from the wound and 121 +/- 47 mg/l from the collection system), but no clottable fibrinogen. The Western immunoblots all visualized the same patterns; in drained blood there were split-products mainly from cross-linked fibrin, in contrast to arterial blood which contained only normal fibrinogen. This indicates a strong fibrinolysis in the surgical wound after closure, with concentrations of fibrin degradation products that may impair local coagulation, and if infused, might interfere with general haemostasis.  相似文献   
953.
Background and purpose There is considerable controversy about the treatment of complex, displaced proximal humeral fractures. Various types of head-preserving osteosynthesis have been suggested. This prospective case series was designed to evaluate the perioperative and early postoperative complications associated with fixed-angle implants and to record outcome after bone healing.Patients and methods Fractures of the proximal humerus were stabilized surgically in 87 patients (mean age 64 (16–93) years) by application of a fixed-angle plate (65 PHILOS, 22 T-LCP). There were 34 2-segment fractures, 42 3-segment fractures, and 11 4-segment fractures, including 7 dislocation fractures. Follow-up assessment after a minimum of 12 months was based on the Constant, UCLA, and DASH scores and on radiographs.Results Postoperative complications included soft tissue problems (n = 9), humeral head necrosis (n = 9), screw perforation (n = 11), secondary displacements (n = 14), and delayed fracture healing (n = 4). Treatment outcomes recorded on the various scores were very good in 60–82% of the cases.Interpretation Screw perforation of fixed-angle implants has replaced the complications of secondary displacement and implant loosening after using conventional plates. Even with the use of fixed-angle implants, fractures of the proximal humerus are associated with a high complication rate and sometimes poor outcome.  相似文献   
954.
Background and purpose This randomized study compared clinical results after surgery for posttraumatic shoulder instability with either an anatomical repair or an older, less anatomical but commonly used method. The less anatomical procedure has been considered quicker and less demanding, but it has been questioned regarding the clinical result. We therefore wanted to compare the clinical outcome of the two different procedures. Our hypothesis was that the anatomical repair would give less residual impairment postoperatively.Methods Patients with anterior posttraumatic shoulder instability were consecutively randomized on the day before surgery to either a Bankart repair using Mitek GI/GII anchors combined with capsular imbrication (B) (n = 33) or a Putti-Platt procedure (P) (n = 33). Follow-up was performed by examination at 2 years and using a self-evaluation score at 10 years.Results At the 2-year follow-up, we found no difference in muscle strength between patients treated with the two surgical methods and there were no statistically significant differences in the Rowe scores (mean 90 units for both groups). Compared to preoperatively, the decrease in external rotation 2 years after surgery was 10 degrees in the P group and 3 degrees in the B group (p = 0.03). 10 years after surgery, 62 of 66 patients replied to a questionnaire sent by mail. It included a self-evaluating quality of life score for shoulder instability (WOSI) for evaluation of their shoulder function. In the P group 15 patients and in the B group 19 patients reported they had experienced either a redislocation or a subluxation with a new feeling of shoulder instability. Mean WOSI score was similar in the P and B groups: 80% and 83%, respectively. The WOSI score was 87% for patients with stable shoulders (n = 28) and 77% for those with unstable shoulders (n =34) (p = 0.005).Interpretation With assessment of pain and general shoulder function, only a small difference was found between the two methods. The WOSI scores for stable shoulders indicated that some shoulders still had impaired function even though the shoulders had become stable.  相似文献   
955.
956.
The major cause of coronary heart disease, hypertension, non-insulin-dependent diabetes and obesity in adults in developed countries appears to be the result of risk factors that are introduced by way of their life-styles. Many developing countries are also noting increases in morbidity and mortality from these diseases. There is increasing evidence of common risk factors in the aetiology of these chronic disorders and two or more of these diseases may coexist in the same subjects. This evidence provides a strong rationale for a community-based, integrated approach to the primary prevention of such non-communicable diseases by the reduction of the level of risk factors. This may be achieved by community-based programmes which stress the importance of a healthy life-style, such as the practice of good nutrition, weight reduction in the obese, increased physical activity, the avoidance of stress and a reduction in alcohol and cigarette consumption.  相似文献   
957.
958.
959.
We have conducted a telemedicine project between two of Norway's largest hospitals (Rikshospitalet and Ullev?l Hospital) with a focus on image-guided surgical and radiological procedures. Video was broadcast using a 34 Mbit/s ATM network. This resulted in changes in the local work practice to accommodate and facilitate the communication. It also required changes to the surgeon's tasks to improve communication with remote viewers. These changes were not trivial and can be viewed as signs of a shift towards a more public kind of surgery and interventional radiology, brought about by new technology.  相似文献   
960.
The steady-state tissue/blood partition coefficients of fentanyl and alfentanil were determined in 13 organs and tissues in the rat. A 6-h infusion of both drugs was used in order to achieve steady-state. Blood and tissue concentrations of drugs were measured by gas-liquid chromatography. The partition coefficients of fentanyl were two- to 30-fold higher than those of alfentanil. These data were then used in a physiologic pharmacokinetic model describing the disposition of the two opioids in humans. The model predicted the plasma pharmacokinetics of these drugs in humans reasonably well. However, simulation beyond 24 h after a bolus administration showed a terminal half-life of 20 h for fentanyl, i.e., an elimination phase that has not yet been described in actual pharmacokinetic studies. In keeping with this, the volume of distribution of fentanyl in the model was also larger than expected. The simulated tissue concentration curves of fentanyl and alfentanil in humans could be used to explain the propensity of fentanyl to give secondary peaks in plasma concentration curves and the difference in effect kinetics between the two opioids. Physiologic pharmacokinetic modeling, based on measured data in small animals, can generate information that is not obtainable by empirical methods in humans.  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