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   75323篇
  免费   4943篇
  国内免费   301篇
耳鼻咽喉   855篇
儿科学   1783篇
妇产科学   1357篇
基础医学   10252篇
口腔科学   1639篇
临床医学   7194篇
内科学   16086篇
皮肤病学   1183篇
神经病学   7639篇
特种医学   3508篇
外国民族医学   9篇
外科学   11628篇
综合类   737篇
一般理论   46篇
预防医学   5398篇
眼科学   1618篇
药学   4817篇
中国医学   163篇
肿瘤学   4655篇
  2023年   303篇
  2022年   538篇
  2021年   1226篇
  2020年   864篇
  2019年   1280篇
  2018年   1505篇
  2017年   1201篇
  2016年   1386篇
  2015年   1667篇
  2014年   2265篇
  2013年   3123篇
  2012年   4749篇
  2011年   5008篇
  2010年   2963篇
  2009年   2674篇
  2008年   4682篇
  2007年   4854篇
  2006年   4714篇
  2005年   4731篇
  2004年   4450篇
  2003年   4365篇
  2002年   4181篇
  2001年   1049篇
  2000年   935篇
  1999年   1055篇
  1998年   989篇
  1997年   809篇
  1996年   696篇
  1995年   693篇
  1994年   551篇
  1993年   534篇
  1992年   642篇
  1991年   574篇
  1990年   506篇
  1989年   539篇
  1988年   466篇
  1987年   496篇
  1986年   468篇
  1985年   444篇
  1984年   453篇
  1983年   434篇
  1982年   448篇
  1981年   401篇
  1980年   367篇
  1979年   329篇
  1978年   296篇
  1977年   276篇
  1975年   242篇
  1974年   235篇
  1973年   223篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Summary Partial anomalous pulmonary venous connections (PAPVCs) are rare in association with an intact atrial septum. However, the diagnosis should be considered in patients with otherwise unexplained findings of left-to-right shunt and right heart enlargement. An unusual variant is presented, which we considered unsuitable for operative repair, based on findings at catheterization. Developmental, hemodynamic, and surgical considerations are discussed.  相似文献   
93.
94.
To perform true three-dimensional activation experiments in the human brain, dedicated localized echo-volume imaging (L-EVI) methods were developed. Three-dimensional acquisition allows generation of activation maps with minimal vascular enhancement related to inflow effects. The rapid acquisition of the L-EVI (~100 msec) reduces signal instabilities caused by motion, facilitating the detection of the small intensity changes expected with brain activation. Single-shot L-EVI was performed on normal volunteers at 1.5 T, imaging a three-dimensional predefined volume (240 × 45 × 45 mm3) in the superior portion of the brain with a spatial resolution of 3.75 × 5 × 5 mm3. Increased brain coverage was achieved with a multi-volume imaging (three-shot) version, which simultaneously achieved effective suppression of signals from cerebrospinal fluid. In addition, both asymmetric spin-echo (ASE) and spin-echo (SE) versions of the technique were used to detect blood oxygenation level dependent (BOLD) signal changes in the motor cortex with a finger-tapping paradigm. Images obtained by the L-EVI sequence were qualitatively comparable to standard multislice two-dimensional echo-planar images. Both ASE and SE functional MRI (fMRI) experiments showed consistent activation in the contralateral primary sensorimotor cortex. Furthermore, significant differences in location and magnitude of activation was observed between the two methods, confirming theoretical predictions.  相似文献   
95.
Abstract: Lobular carcinoma in situ (LCIS) has gone from a rare form of mammary cancer to a marker of increased risk. Treatment options have undergone a corresponding change from ipsilateral mastectomy with axillary node dissection to observation once it became clear that the majority of patients did not progress to invasive cancer. However, recent events suggest a re-evaluation of LCIS management options. It is clear that even meticulous observation may fail to detect invasive cancer before systemic spread has taken place. This fact plus the identification of breast cancer genes have brought a renewed interest in prophylactic mastectomy. At the same time pathologists feel that it is possible to identify microscopic features of LCIS pointing to an increased likelihood of developing invasive cancer. As a result physicians are being asked to better quantitate risks for individual patients. Most patients with LCIS do not need bilateral mastectomies, but we are coming closer to identifying the minority that would be better served by prophylactic surgery.  相似文献   
96.
We report on a woman with a an 8-year history of multiple system atrophy with predominance of parkinsonism who developed jaw-locking oromandibular dystonia within hours after insertion of ill-fitting dentures. Dystonia spread rapidly to involve other facial muscles and the larynx causing stridor with respiratory failure necessitating crush intubation.  相似文献   
97.
98.
99.
The interactive use of magnetic resonance imaging (MRI) techniques is increasing in operating theaters. A study was performed on 17 male company volunteers to assess the neurobehavioral effects of exposure to magnetic fields from a 1.5 Tesla MRI system. The subjects' neurobehavioral performances on a neurobehavioral test battery were compared in four 1-hr sessions with and without exposure to magnetic fields, and with and without additional movements. Adverse effects were found for hand coordination (-4%, P < 0.05; Pursuit Aiming II) and near visual contrast sensitivity (-16% and -15%, P < 0.10; Vistech 6000). The results from the remaining tests were inconclusive due to a strong learning effect. No additional effect from gradient fields was detected. The results indicate that working near a 1.5 Tesla MRI system may lead to neurobehavioral effects. Further research is recommended, especially in members of operating teams using interactive MRI systems.  相似文献   
100.
The files of 334 consecutive cadaver kidney (CK) and of 27 living related (LR) transplantations (T) in children and adolescents performed from 1973 to 1984 have been reviewed. Following cadaver transplantation, 52 patients (15%) never had hypertension (HT), 41 patients (12%) had only initial HT up to 6 months after transplantation and 18 other patients (5%) exhibited transient HT episodes while on high-dose steroid therapy. Finally, 209 patients (62%) had HT for periods longer than 6 months and 16 patients (5%) until death or graft failure within the first 3 months. Chronic graft rejection was the major cause of HT, but other factors either isolated or in association were also present. Renal artery stenosis (RAS) was diagnosed in 43 cases (13%) 2–17 months post-transplantation; 10 of these were operated upon (5 successfully) and 9 underwent transluminal angioplasty with a single success. Nine cases of RAS resolved spontaneously. HT was attributed to the host kidney in 10 cases (3%) and to recurrence of primary renal disease in 9 (3%). HT observed after CKT was sometimes severe and difficult to control. Acute complications from HT were recorded in 35 cases, with 6 deaths and 2 severe neurological sequelae. Among 25 LRT, 11 cases (40%) had no HT 13 (48%) had HT for longer than 6 months. In this group, no case of RAS was observed and only one complication (without sequelae) was noted. In conclusion, HT is a frequent and sometimes severe complication post-transplantation in children and adolescents.  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