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   56099篇
  免费   3286篇
  国内免费   624篇
耳鼻咽喉   985篇
儿科学   636篇
妇产科学   828篇
基础医学   9768篇
口腔科学   1356篇
临床医学   4915篇
内科学   10562篇
皮肤病学   1876篇
神经病学   3983篇
特种医学   2982篇
外科学   7486篇
综合类   220篇
现状与发展   1篇
一般理论   17篇
预防医学   2714篇
眼科学   1234篇
药学   5012篇
中国医学   625篇
肿瘤学   4809篇
  2023年   428篇
  2022年   1327篇
  2021年   2061篇
  2020年   986篇
  2019年   1289篇
  2018年   1670篇
  2017年   1240篇
  2016年   1760篇
  2015年   2565篇
  2014年   3065篇
  2013年   3496篇
  2012年   5314篇
  2011年   4808篇
  2010年   2809篇
  2009年   2366篇
  2008年   3418篇
  2007年   3106篇
  2006年   2656篇
  2005年   2355篇
  2004年   2027篇
  2003年   1694篇
  2002年   1440篇
  2001年   1367篇
  2000年   1266篇
  1999年   911篇
  1998年   368篇
  1997年   268篇
  1996年   212篇
  1995年   180篇
  1994年   153篇
  1993年   136篇
  1992年   339篇
  1991年   321篇
  1990年   282篇
  1989年   261篇
  1988年   247篇
  1987年   250篇
  1986年   177篇
  1985年   165篇
  1984年   120篇
  1983年   111篇
  1982年   55篇
  1981年   58篇
  1979年   81篇
  1978年   68篇
  1975年   50篇
  1974年   60篇
  1973年   51篇
  1972年   50篇
  1970年   49篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
81.
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   
82.
83.
84.
85.
86.
87.
88.
Torsion of greater omentum is a rare cause of acute abdomen. However, it should be included in the differential diagnoses in addition to acute cholecystitis, acute appendicitis, cecal diverticulitis, and other variable causes of acute abdomen. Diagnosis is usually made at laparotomy for suspected appendicitis. In some cases, computed tomography demonstrates a successful preoperative detection of omental torsion. We report a case of surgically and pathologically proven torsion with subsequent infarction of greater omentum presented as an acute abdominal pain.  相似文献   
89.
The conjugate of antisense c-raf oligonucleotide (ODN) and poly(ethylene glycol) (PEG) was synthesized for intracellular ODN delivery. When combined with polyethylenimine (PEI), the ODN-PEG conjugate self-associated to form polyelectrolyte complex micelles in aqueous solution. The effective hydrodynamic diameter of the micelles was ca. 70 nm with a narrow size distribution. Flow cytometry analysis indicated that the cellular uptake of the micelles by A2780 cells was much higher than that of ODN alone. The micelles also showed a superior antiproliferative activity against ovarian cancer cells in vitro and in vivo.  相似文献   
90.
RASER: a new ultrafast magnetic resonance imaging method.   总被引:1,自引:0,他引:1  
A new MRI method is described to acquire a T(2)-weighted image from a single slice in a single shot. The technique is based on rapid acquisition by sequential excitation and refocusing (RASER). RASER avoids relaxation-related blurring because the magnetization is sequentially refocused in a manner that effectively creates a series of spin echoes with a constant echo time. RASER uses the quadratic phase produced by a frequency-swept chirp pulse to time-encode one dimension of the image. In another implementation the pulse can be used to excite multiple slices with phase-encoding and frequency-encoding in the other two dimensions. The RASER imaging sequence is presented along with single-shot and multislice images, and is compared to conventional spin-echo and echo-planar imaging sequences. A theoretical and empirical analysis of the spatial resolution is presented, and factors in choosing the spatial resolution for different applications are discussed. RASER produces high-quality single-shot images that are expected to be advantageous for a wide range of applications.  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