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   22274篇
  免费   2164篇
  国内免费   57篇
耳鼻咽喉   209篇
儿科学   538篇
妇产科学   466篇
基础医学   3209篇
口腔科学   408篇
临床医学   2077篇
内科学   4609篇
皮肤病学   289篇
神经病学   2079篇
特种医学   773篇
外科学   3217篇
综合类   646篇
一般理论   65篇
预防医学   2359篇
眼科学   668篇
药学   1625篇
中国医学   24篇
肿瘤学   1234篇
  2023年   134篇
  2022年   207篇
  2021年   467篇
  2020年   262篇
  2019年   427篇
  2018年   483篇
  2017年   364篇
  2016年   364篇
  2015年   498篇
  2014年   612篇
  2013年   905篇
  2012年   1125篇
  2011年   1260篇
  2010年   703篇
  2009年   590篇
  2008年   1113篇
  2007年   1127篇
  2006年   968篇
  2005年   1025篇
  2004年   993篇
  2003年   910篇
  2002年   872篇
  2001年   567篇
  2000年   559篇
  1999年   549篇
  1998年   276篇
  1997年   229篇
  1996年   211篇
  1995年   226篇
  1994年   202篇
  1993年   192篇
  1992年   390篇
  1991年   406篇
  1990年   383篇
  1989年   401篇
  1988年   317篇
  1987年   341篇
  1986年   317篇
  1985年   378篇
  1984年   306篇
  1983年   248篇
  1982年   162篇
  1980年   151篇
  1979年   209篇
  1978年   164篇
  1977年   134篇
  1975年   141篇
  1974年   145篇
  1973年   140篇
  1972年   150篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
We investigated whether structural white matter abnormalities, in the form of disruption of axonal coherence and integrity as measured with diffusion tensor imaging (DTI), constitute an underlying pathological mechanism of idiopathic dystonia (ID), independent of genotype status. We studied seven subjects with ID: all had cervical dystonia as their main symptom (one patient also had spasmodic dysphonia and two patients had concurrent generalized dystonia, both DYT1‐negative). We compared DTI MR images of patients with 10 controls, evaluating differences in mean diffusivity (MD) and fractional anisotropy (FA). ID was associated with increased FA values in the thalamus and adjacent white matter, and in the white matter underlying the middle frontal gyrus. ID was also associated with increase in MD in adjacent white matter to the pallidum and putamen bilaterally, left caudate, and in subcortical hemispheric regions, including the postcentral gyrus. Abnormal FA and MD in patients with ID indicate that abnormal axonal coherence and integrity contribute to the pathophysiology of dystonia. These findings suggest that ID is not only a functional disorder, but also associated with structural brain changes. Impaired connectivity and disrupted flow of information may contribute to the impairment of motor planning and regulation in dystonia. © 2006 Movement Disorder Society  相似文献   
32.
33.
34.
The release of prostacyclin (PGI2) and von Willebrand factor (vWF) from human umbilical vein endothelial cells (HUVEC) was examined to determine if aprotinin had any effects on these endothelial cell reactions. These end-points were chosen to indicate if this serine protease inhibitor caused alterations in the control of haemostatic function by endothelium, in the light of the improvement in haemostasis seen in patients given aprotinin therapy at the time of open heart surgery. Stimuli used to promote secretion of prostacyclin and vWF were human alpha-thrombin, histamine, protamine sulphate, poly-L-lysine and phorbol myristate acetate. Aprotinin (30 microMs) had no significant effect on the basal or stimulated release of PGI2 or vWF from HUVEC.  相似文献   
35.
We have previously described the development of new hepatic surgical techniques using the ultrasonic surgical dissector. With 10 years' experience, we have found that major liver resections have been simplified and that the technique is repeatable in hands other than our own. Thirty-three patients had 37 tumors, averaging 5.65 cm in size, resected with an average blood loss of only 1,020 mL per case, which included 5 right trisegmentectomies, 12 lobectomies, 15 segmental resections, and 4 subsegmental resections. Twenty-two patients had metastatic colorectal cancer. Blood transfusion requirements averaged only 2.24 units in long-term survivors, which was significantly less than the 3.5 units received by patients who have since died (p = 0.092). There were no operative deaths. The median survival of these 22 patients was 56 months, and the 5-year actuarial survival rate was 35%. All of the early deaths occurred in patients with more than four tumors, and no patient with less than four tumors died before 42 months with recurrent disease. Six patients had bilateral tumors, and the fact that patients survived into the fourth and fifth post-resectional year indicates that resection was worthwhile. All these patients had Dukes' C primary tumors, but we found no statistical difference in survival between patients with Dukes' B and Dukes' C lesions. The results indicate that hepatic resection with the ultrasonic surgical dissector decreases blood loss, requires few transfusions, is safe to perform, and is associated with excellent long-term survival.  相似文献   
36.
Assessment of attitudes amongst health care professionals to suicide prevention reveals a considerable degree of doubt with regards to its feasibility and appropriateness. The various professional groups may vary considerably in the degree of negative attitudes which they exhibit. Such findings suggest that there is an urgent need to ensure that health care professionals are fully informed about the key facts concerning suicide and preventive strategies. Key elements of clinical practice and service organization with regards to suicide prevention are discussed.  相似文献   
37.
38.
39.
The objectives of this study were to use computer-generated phantoms containing real subject motion to: (1) compare the sensitivity of four commonly used fMRI software packages and (2) compare the sensitivity of three statistical analysis strategies with respect to motion correction. The results suggest that all four packages perform similarly in fMRI statistical analysis with SPM2 having slightly higher sensitivity. The most sensitive analysis technique was to perform motion correction and include the realignment parameters as regressors in the general linear model. This approach applies to all four packages examined and can be most beneficial when stimulus-correlated motion is present.  相似文献   
40.
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