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   24438篇
  免费   1712篇
  国内免费   58篇
耳鼻咽喉   348篇
儿科学   458篇
妇产科学   521篇
基础医学   3148篇
口腔科学   388篇
临床医学   2902篇
内科学   4808篇
皮肤病学   341篇
神经病学   2128篇
特种医学   932篇
外科学   4273篇
综合类   208篇
一般理论   51篇
预防医学   1832篇
眼科学   604篇
药学   1603篇
中国医学   21篇
肿瘤学   1642篇
  2024年   28篇
  2023年   259篇
  2022年   433篇
  2021年   1036篇
  2020年   519篇
  2019年   891篇
  2018年   959篇
  2017年   697篇
  2016年   744篇
  2015年   837篇
  2014年   1252篇
  2013年   1402篇
  2012年   2278篇
  2011年   2306篇
  2010年   1196篇
  2009年   1087篇
  2008年   1665篇
  2007年   1646篇
  2006年   1481篇
  2005年   1381篇
  2004年   1171篇
  2003年   1032篇
  2002年   868篇
  2001年   134篇
  2000年   108篇
  1999年   98篇
  1998年   113篇
  1997年   77篇
  1996年   48篇
  1995年   33篇
  1994年   36篇
  1993年   36篇
  1992年   31篇
  1991年   41篇
  1990年   22篇
  1989年   26篇
  1988年   29篇
  1987年   13篇
  1986年   23篇
  1985年   24篇
  1984年   17篇
  1983年   17篇
  1982年   10篇
  1981年   10篇
  1980年   14篇
  1979年   16篇
  1978年   7篇
  1976年   6篇
  1970年   5篇
  1968年   5篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
This study evaluated the effects of tobacco Purchase, Use and Possession (PUP) laws on student perceptions of adolescent tobacco use within towns and schools. Twenty‐four towns were randomly assigned into two conditions, the experimental condition (E PUP) involved efforts to increase both PUP law enforcement and reduce minors' access to commercial sources of tobacco, whereas the control condition (C) focused only on efforts to reduce minors' access to commercial sources of tobacco. A hierarchical linear modeling analytical approach was selected due to the multilevel data and nested design. The present study found that over time, youth in the experimental PUP condition observed less youth tobacco usage at school and in their town, and perceived lower rates of tobacco among their peers at school and among friends than youth in the control condition. The findings suggest that PUP law enforcement might be used to strengthen community norms against youth tobacco use.  相似文献   
14.
15.
Prostatitis accounts for almost 2 million office visits to urologists and primary care physicians. The label “prostatitis” refers to a diverse constellation of symptoms and disease processes. The diagnosis and treatment of this disorder present numerous challenges for the physician, including a lack of abnormal findings on physical examination, laboratory tests, and radiographic images. In this article, we offer a review of the current literature and recommendations for the evaluation and diagnosis of the patient presenting with prostatitis.  相似文献   
16.
17.
BACKGROUND: Past receiver operating characteristic (ROC) studies have demonstrated that single photon emission computed tomography (SPECT) perfusion imaging by use of iterative reconstruction with combined compensation for attenuation, scatter, and detector response leads to higher area under the ROC curve (A(z)) values for detection of coronary artery disease (CAD) in comparison to the use of filtered backprojection (FBP) with no compensations. A new ROC study was conducted to investigate whether this improvement still holds for iterative reconstruction when observers have available all of the imaging information normally presented to clinical interpreters when reading FBP SPECT perfusion slices. METHODS AND RESULTS: A total of 87 patient studies including 50 patients referred for angiography and 37 patients with a lower than 5% likelihood for CAD were included in the ROC study. The images from the two methods were read by 4 cardiology fellows and 3 attending nuclear cardiologists. Presented for the FBP readings were the short-axis, horizontal long-axis, and vertical long-axis slices for both the stress and rest images; cine images of both the stress and rest projection data; cine images of selected cardiac-gated slices; the CEQUAL-generated stress and rest polar maps; and an indication of patient gender. This was compared with reading solely the iterative reconstructed stress slices with combined compensation for attenuation, scatter, and resolution. With A(z) as the criterion, a 2-way analysis of variance showed a significant improvement in detection accuracy for CAD for the 7 observers (P = .018) for iterative reconstruction with combined compensation (A(z) of 0.895 +/- 0.016) over FBP even with the additional imaging information provided to the observers when scoring the FBP slices (A(z) of 0.869 +/- 0.030). When the groups of 3 attending physicians or 4 cardiology fellows were compared separately, the iterative technique was not statistically significantly better; however, the A(z) for each of the 7 observers individually was larger for iterative reconstruction than for FBP. Compared with results from our previous studies, the additional imaging information did increase the diagnostic accuracy of FBP for CAD but not enough to undo the statistically significantly higher diagnostic accuracy of iterative reconstruction with combined compensation. CONCLUSIONS: We have determined through an ROC investigation that included two classes of observers (experienced attending physicians and cardiology fellows in training) that iterative reconstruction with combined compensation provides statistically significantly better detection accuracy (larger A(z)) for CAD than FBP reconstructions even when the FBP studies were read with all of the extra clinical nuclear imaging information normally available.  相似文献   
18.
19.
20.
The adequate treatment of methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis has intrigued clinicians for some time. As the resistance of these pathogens, coupled with the increase in community-acquired cases, continues steadily to rise, clinicians are finding it useful to employ multi-modal approaches for efficacious treatment. The authors present a single case report of a patient with recurrent MRSA osteomyelitis, lumbar paraspinal and epidural abscess. He was found to have decreased muscle strength and was hyporeflexic in the involved extremity. Serum testing demonstrated MRSA bacteremia. Neuroimaging studies revealed evidence of paraspinal abscess and a presumed herniated nucleus pulposus at the L5/S1 interspace with significant nerve root compromise. Despite antimicrobials, his symptoms persisted, necessitating surgical exploration. At surgery, paraspinal and epidural abscesses were encountered and debrided; however, no herniated disc was visualized. This case demonstrates the diagnostic and therapeutic dilemmas with which these lesions present. We postulate that the MRSA osteomyelitis/discitis pathogens were walled off in the disc space and subsequently inoculated the soft tissues with ensuing bacteremia. We concur that antimicrobial treatment should be the first line of therapy for these patients; however, surgical debridements and cautious spinal instrumentation should be employed where appropriate.  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