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   71197篇
  免费   4557篇
  国内免费   1933篇
耳鼻咽喉   459篇
儿科学   1145篇
妇产科学   622篇
基础医学   7892篇
口腔科学   1152篇
临床医学   6565篇
内科学   7744篇
皮肤病学   408篇
神经病学   9058篇
特种医学   2159篇
外国民族医学   3篇
外科学   5555篇
综合类   10933篇
现状与发展   6篇
预防医学   10413篇
眼科学   995篇
药学   7644篇
  102篇
中国医学   2598篇
肿瘤学   2234篇
  2024年   230篇
  2023年   1164篇
  2022年   2086篇
  2021年   2849篇
  2020年   2641篇
  2019年   2421篇
  2018年   2394篇
  2017年   2065篇
  2016年   2157篇
  2015年   2144篇
  2014年   4502篇
  2013年   4866篇
  2012年   4263篇
  2011年   4739篇
  2010年   3679篇
  2009年   3516篇
  2008年   3645篇
  2007年   3420篇
  2006年   3088篇
  2005年   2629篇
  2004年   2163篇
  2003年   1920篇
  2002年   1517篇
  2001年   1341篇
  2000年   1107篇
  1999年   953篇
  1998年   912篇
  1997年   881篇
  1996年   742篇
  1995年   700篇
  1994年   682篇
  1993年   584篇
  1992年   556篇
  1991年   539篇
  1990年   440篇
  1989年   390篇
  1988年   408篇
  1987年   379篇
  1986年   353篇
  1985年   489篇
  1984年   410篇
  1983年   261篇
  1982年   274篇
  1981年   252篇
  1980年   233篇
  1979年   150篇
  1978年   142篇
  1977年   123篇
  1976年   90篇
  1974年   51篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
31.
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   
32.
1.5T超导磁共振制冷系统的工作原理及日常维护   总被引:1,自引:0,他引:1  
介绍GE 1.5T超导磁共振制冷系统的组成和工作原理,讨论日常维护的要点及其必要性。  相似文献   
33.
Horner syndrome     
Horner syndrome is an uncommon but important clinical entity, representing interruption of the sympathetic pathway to the eye and face. Horner syndrome is almost always diagnosed clinically, though pharmacological testing can be used to confirm the diagnosis. Imaging modalities such as PET, CT and MRI are important components of work‐up for patients presenting with acquired Horner syndrome. Our patient’s presentation with Horner syndrome unmasked the causative superior sulcus squamous cell carcinoma and a coincidental lower lobe adenocarcinoma. Successful radical treatment of these cancers resulted in complete resolution of the syndrome and disease‐free survival at 18 months. We review the anatomy and pathophysiology underlying this and other causes of Horner syndrome.  相似文献   
34.
Summary— Experimental and clinical data clearly demonstrate that calcium antagonists (CA) may have an action on the central nervous system (CNS). The cerebrovascular action of CA justifies their use in cerebral ischaemia, vasospasm and hypoxia. Several clinical trials have demonstrated such beneficial effects. On the other hand a number of reports indicate that CA may have a direct neuronal effect, although most of such trials have not been verified or are mere case reports. In addition, the large number of conditions susceptible to being corrected by CA is impressive: epilepsy, pain, dystonia, dyskinesia, psychiatric conditions, etc. Other papers are disconcerting that report extrapyramidal disorders induced by flunarizine and cinnarizine in the elderly, whereas nicardipine does not produce such side effects and may even alleviate some parkinsonian symptoms. In various experimental models (e.g. stroke, oedema), pharmacological effects have been shown to vary from one compound to the other. Two main questions are yet to be answered: 1) has the direct neuronal effect of CA been clearly established? 2) are the multiple clinical effects on the CNS really linked to calcium antagonism?  相似文献   
35.
基于无线网络及条形码技术的图书排架、定位系统   总被引:3,自引:2,他引:1  
利用无线网络与条形码技术,建立起图书排架、定位系统,可实现图书排架和图书的准确定位.该系统可有效地解决传统管理方法易产生的乱架和死书问题,提高图书借阅效率并降低管理人员的工作强度.  相似文献   
36.
Summary Isolated angiitis of the central nervous system (IAC) was diagnosed in a 40-year-old Caucasian male by histological examination of a leptomeningeal biopsy specimen, and the exclusion of systemic inflammatory or infective disease. Therapy with prednisone 30 mg/day and cyclophosphamide 100 mg/day resulted in clinical and radiological improvement, which have been maintained for an 8-month follow-up period. Magnetic resonance imaging (MRI) showed lesions implicating involvement of specific penetrating vessels at the base of the brain, an unusual complication of IAC, and allowed an accurate MRI-clinical correlation.  相似文献   
37.
38.
The ubiquitous existence of calcium-activated neutral protease (CANP, calpain), an enzyme whose activity is regulated by calcium ions and a specific endogenous CANP inhibitor (calpastatin), is well known. Although there has been much investigation concerning the distribution and role of CANP, investigations of the distribution of the CANP inhibitor using immunohistochemical techniques are rare. We made antiserum against a 40K fragment of cDNA corresponding to two C-terminal repeats of rat liver CANP inhibitor expressed in Escherichia coli. Using this antiserum, we examined the distribution of CANP inhibitor in the rat central nervous system by the ABC technique and compared it with the distribution of CANP. Neurons and glias were stained, with the cytosol stained diffusely and the cell membranes stained clearly and strongly. Axons and myelin were stained faintly, but nuclei and vessels were not stained. The distribution of CANP inhibitor was thus found to be similar to that of CANP.  相似文献   
39.
Cholesterol intakes in Britain have been re-estimated by analysing Total Diet samples taken in 1991 and from 1993 National Food Survey records. The Total Diet samples contained only 284 mg/day compared with 319 mg/day in 1987 and 337 mg/day in 1981, while the National Food Survey showed intakes had fallen to 238 mg/day from 259 mg/day in 1990 and 405 mg/day in 1970-75. More details of the intakes by adults in 1986/87 are given, and compared with the results from the other methods. Daily intakes of eight phytosterols were also estimated, the main ones being β-sitosterol, campesterol, stigmasterol and 57-stigmastenol whose intakes were 104, 49, 10 and 4 mg/day, respectively, in 1991. These intakes had increased since 1981, reflecting the rising consumption of vegetable oils.  相似文献   
40.
We describe the pattern and progression of atrophy delineated using fluid registration of serial magnetic resonance imaging scans in a case of multiple system atrophy (MSA). The in vivo findings were consistent with those found at postmortem, including significant supratentorial atrophy concurrent with an unusual degree of cognitive impairment for MSA.  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