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   166653篇
  免费   10700篇
  国内免费   1292篇
耳鼻咽喉   2439篇
儿科学   3072篇
妇产科学   3847篇
基础医学   24978篇
口腔科学   3421篇
临床医学   15556篇
内科学   31690篇
皮肤病学   4599篇
神经病学   12472篇
特种医学   8435篇
外科学   22612篇
综合类   2188篇
现状与发展   5篇
一般理论   84篇
预防医学   9839篇
眼科学   4413篇
药学   14148篇
中国医学   1648篇
肿瘤学   13199篇
  2023年   1021篇
  2022年   2856篇
  2021年   5000篇
  2020年   2569篇
  2019年   3716篇
  2018年   4564篇
  2017年   3368篇
  2016年   4384篇
  2015年   5927篇
  2014年   7223篇
  2013年   8717篇
  2012年   13193篇
  2011年   12787篇
  2010年   7567篇
  2009年   6334篇
  2008年   9614篇
  2007年   9437篇
  2006年   8639篇
  2005年   8224篇
  2004年   7322篇
  2003年   6333篇
  2002年   5517篇
  2001年   4422篇
  2000年   4054篇
  1999年   3306篇
  1998年   1337篇
  1997年   1006篇
  1996年   961篇
  1995年   867篇
  1994年   760篇
  1993年   651篇
  1992年   1584篇
  1991年   1584篇
  1990年   1366篇
  1989年   1249篇
  1988年   1162篇
  1987年   1057篇
  1986年   1019篇
  1985年   896篇
  1984年   654篇
  1983年   567篇
  1982年   406篇
  1981年   387篇
  1980年   340篇
  1979年   523篇
  1978年   415篇
  1977年   395篇
  1976年   347篇
  1974年   362篇
  1973年   328篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
82.
The relationship of large and vascularized chorioangiomas to adverse pregnancy outcome is well recognized. We present a patient with a large placental tumor and signs of impending fetal cardiac failure. The angioarchitecture of the tumor depicted by three-dimensional (3D) power Doppler ultrasound enabled us to accurately diagnose a placental chorioangioma. During the follow-up period, quantitative flow data obtained using 3D power Doppler indicated altered hemodynamics in the tumor and concomitant improvement in the condition of the fetus, enabling us to manage the mother conservatively. Spontaneous delivery occurred at 38 weeks without any complications. This report demonstrates the potential value of 3D power Doppler in prenatal diagnosis and monitoring of pregnancies complicated by large, vascularized chorioangioma.  相似文献   
83.
84.
85.
Cerebral infarction as a complication of tubercular (TB) meningitis is not uncommon, but an adequate comparison of patients with and without stroke has not been carried out. This study was performed to evaluate the clinical characteristics of cerebral infarction secondary to TB meningitis, and to investigate predictive factors for cerebral infarction in patients with TB meningitis. Patients with TB meningitis were recruited over a period of 56 months. They were divided into two groups, those with and those without stroke. Demographic features and clinical, laboratory, and neuroradiological findings were compared between the two groups. We classified strokes into subtypes using neuroimaging findings. Of the 38 patients who were diagnosed with TB meningitis, eight also experienced cerebral infarction. The percentage of cerebrospinal fluid leukocytes that were neutrophils was significantly higher in patients with stroke (68%) than in patients without stroke (31%; p=0.0001). Upon initial CT imaging, meningeal enhancement was found in 11 patients, and of these patients, six experienced stroke. There were no significant differences between the groups with respect to other clinical and laboratory features, including demographic features, time between meningitis onset and treatment initiation, peripheral white blood cell count, and cerebrospinal fluid findings. Five of the eight patients who developed stroke had lacunar infarcts. One of the three patients with territorial nonlacunar infarction died due to herniation. When treating patients with TB meningitis, the possibility of cerebral infarction should be considered when patients develop focal neurological signs, meningeal enhancement on a CT scan, and sustained polymorphic cerebrospinal fluid pleocytosis.  相似文献   
86.
The current report focuses on two patients of the same age who presented similar appearances on initial anteroposterior chest images. Follow-up images showed superoanterior and superoposterior mediastinal lesions. The first patient with noninvasive cystic thymoma was suspected before surgery, while the pathologic diagnosis was intrathoracic phrenic nerve schwannoma. The second patient was with an asymmetric, dumbbell-shaped paravertebral tumor over T3 and T4 on the left side. The preoperative…  相似文献   
87.
Split liver transplantation (SLT) benefits society by increasing the total number of transplants that can be performed, but it is yet unknown if a decreased post-transplant survival (in comparison to whole liver transplantation) would make participation in SLT less appealing to adult liver transplant candidates. A 20-item questionnaire was administered to 50 adult candidates to assess attitudes toward SLT and organ sharing. The overall attitudes of 60% of participants were classified as utilitarian (maximizing benefit to greatest number of candidates), while 26% were classified as self-preserving (maximizing individual benefit) and 14% were undecided. Ninety percent of participants would be willing to share even if expected survival was less than that of whole liver transplantation, and 69% felt that pediatric candidates should have priority over adult candidates. In conclusion, attitudes toward graft sharing and the possibility of compromised survival benefit are not barriers to SLT for most adult liver transplant candidates.  相似文献   
88.
OBJECTIVE: To determine the intraobserver and interobserver reproducibility of measurement of the percentage of protrusion of submucous fibroids into the uterine cavity using three-dimensional saline contrast sonohysterography (3D-SCSH). METHODS: Women diagnosed with submucous uterine fibroids on B-mode two-dimensional (2D) ultrasound scan were invited to join the study and 3D-SCSH was carried out. 3D volume datasets were stored digitally and were examined later using the technique of planar reformatted sections. The reproducibilities of the measurement of fibroid diameter and protrusion ratio into the uterine cavity (ratio of the size of the segment of the fibroid protruding into the cavity to the total diameter of the fibroid) were examined by two independent observers who were unaware of the initial 2D scan findings. Interobserver reproducibility was assessed by calculating the difference between measurements taken by the two operators (limits of agreement) and interclass correlation coefficient. Intraobserver repeatability was assessed by calculating the difference between two measurements for each variable (limits of agreement) and further expressed as an intraclass correlation coefficient. RESULTS: Thirty-three 3D ultrasound volumes were examined. There was a good agreement between the observers in classifying the fibroids as greater or less than 50% confined to the myometrium (Cohen's kappa 0.81). There was no bias in measurements for both variables either between observers or with repeated measurements by each observer. For fibroid diameter and protrusion ratio the inter- and intraclass correlation coefficients were high (0.984-0.995), with narrow limits of agreement. CONCLUSION: 3D-SCSH is a reproducible method for the quantification of the percentage of a submucous fibroid protruding into the uterine cavity.  相似文献   
89.
90.
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