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   66353篇
  免费   4325篇
  国内免费   1891篇
耳鼻咽喉   431篇
儿科学   948篇
妇产科学   586篇
基础医学   7576篇
口腔科学   1090篇
临床医学   6172篇
内科学   6828篇
皮肤病学   366篇
神经病学   8840篇
特种医学   2089篇
外国民族医学   2篇
外科学   4579篇
综合类   10506篇
现状与发展   6篇
预防医学   9910篇
眼科学   701篇
药学   7443篇
  101篇
中国医学   2297篇
肿瘤学   2098篇
  2024年   219篇
  2023年   1034篇
  2022年   1876篇
  2021年   2597篇
  2020年   2444篇
  2019年   1906篇
  2018年   1843篇
  2017年   1856篇
  2016年   2063篇
  2015年   2048篇
  2014年   4188篇
  2013年   4577篇
  2012年   4058篇
  2011年   4442篇
  2010年   3478篇
  2009年   3340篇
  2008年   3457篇
  2007年   3249篇
  2006年   2938篇
  2005年   2493篇
  2004年   2068篇
  2003年   1832篇
  2002年   1446篇
  2001年   1253篇
  2000年   1055篇
  1999年   893篇
  1998年   884篇
  1997年   860篇
  1996年   723篇
  1995年   679篇
  1994年   666篇
  1993年   572篇
  1992年   543篇
  1991年   526篇
  1990年   436篇
  1989年   387篇
  1988年   399篇
  1987年   377篇
  1986年   346篇
  1985年   470篇
  1984年   398篇
  1983年   243篇
  1982年   265篇
  1981年   243篇
  1980年   227篇
  1979年   146篇
  1978年   135篇
  1977年   120篇
  1976年   87篇
  1974年   45篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
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   
42.
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   
43.
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   
44.
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   
45.
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   
46.
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   
47.
48.
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   
49.
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   
50.
In cases with otherwise clinically typical Guillain-Barré syndrome (GBS), pronounced cerebrospinal fluid (CSF) pleocytosis or the mere presence of CSF-polymorphonuclear granulocytes should alert the physician to consider alternative diagnoses. Therefore, we retrospectively studied the neuropathology of central and peripheral nervous system in two cases with a CSF cell count of more than 50/microl and in three cases with a significant proportion of polymorphonuclear granulocytes in the CSF sediment. All cases fulfilled the required criteria for the diagnosis of GBS, the duration from onset to death ranged from 4 to 100 days. Neuropathological investigations included routine staining procedures and immunohistochemistry for antigens of glial and haematopoetic cells as well as for products of relevant neurotropic viruses. Demyelinating polyradiculitis was present in four cases, in one patient with a survival time of 4 days the type of damage to myelinated fibres was unclassifiable. In the central nervous system a consistent finding was diffuse activation of microglia, only one case showed mild meningeal and lower brainstem inflammation. Viral products were generally absent. In summary, the neuropathological findings confirm that marked CSF pleocytosis or the presence of polymorphonuclear granulocytes does not rule out the diagnosis of GBS.  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