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   1219721篇
  免费   81826篇
  国内免费   2061篇
耳鼻咽喉   16835篇
儿科学   33159篇
妇产科学   29933篇
基础医学   173496篇
口腔科学   39249篇
临床医学   99648篇
内科学   246660篇
皮肤病学   26942篇
神经病学   96080篇
特种医学   44921篇
外国民族医学   106篇
外科学   186743篇
综合类   19980篇
现状与发展   2篇
一般理论   313篇
预防医学   94112篇
眼科学   27939篇
药学   92793篇
  3篇
中国医学   3316篇
肿瘤学   71378篇
  2021年   11137篇
  2019年   11572篇
  2018年   17336篇
  2017年   12684篇
  2016年   13257篇
  2015年   15159篇
  2014年   20106篇
  2013年   28535篇
  2012年   41929篇
  2011年   43664篇
  2010年   24328篇
  2009年   22177篇
  2008年   39487篇
  2007年   41687篇
  2006年   41529篇
  2005年   40453篇
  2004年   38664篇
  2003年   36624篇
  2002年   34241篇
  2001年   62862篇
  2000年   65035篇
  1999年   53929篇
  1998年   12761篇
  1997年   11069篇
  1996年   11131篇
  1995年   10260篇
  1994年   9517篇
  1993年   8715篇
  1992年   39669篇
  1991年   37803篇
  1990年   36415篇
  1989年   35299篇
  1988年   32180篇
  1987年   31213篇
  1986年   29226篇
  1985年   27905篇
  1984年   19820篇
  1983年   16799篇
  1982年   8710篇
  1979年   17676篇
  1978年   11852篇
  1977年   10200篇
  1976年   8905篇
  1975年   9904篇
  1974年   11979篇
  1973年   11448篇
  1972年   10804篇
  1971年   10218篇
  1970年   9761篇
  1969年   9320篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
AIM: The complication of nerve injury after greater saphenous vein stripping for varicosity is subjective, and a method for objective evaluation has never been established. The aim of this study was to evaluate postoperative sensory changes by quantitative assessment of current perception threshold (CPT), and to clarify the relation between CPT and symptoms. PATIENTS AND METHODS: Between January 2003 and August 2005, 27 limbs in 18 patients were enrolled. Quantitative sensory function was determined through CPT using a Neurometer (Neurotron, Inc., USA), with which saphenous nerve neural fiber selective minimum sensing values against three electrical stimuli (2000, 250, 5 Hz) were measured. CPT measurements were scheduled on the day before the operation, and 2-7 days, 1, 3, and 6 months after the operation. RESULTS: An increase in CPT value of more than 20% or decrease to below 50% compared to the preoperative value with at least two stimuli was defined as CPT abnormality. Subjective symptoms were observed in 13 limbs in the early postoperative period, and 10 limbs showed CPT abnormality. In 6 limbs with a CPT increase over 20% with all three stimuli, neurological symptoms continued for 6 months. CONCLUSIONS: CPT evaluation provides an objective indication of neurological symptoms in the lower limb following varicose vein surgery.  相似文献   
996.
Paradoxical embolism, describing the passage of venous or right-sided cardiac thrombus into the arterial or systemic circulation through patent foramen ovale, is an uncommon cause of acute arterial occlusion. Here, we report acute Leriche syndrome in a young woman attributable to paradoxical embolism. Ischaemia, patent foramen ovale, and venous thrombosis were the triad of evidence for paradoxical embolism.  相似文献   
997.
998.
To obtain a new model of chronic portal hypertension in the rat, two classical methods to produce portal hypertension, partial portal vein ligation and the oral administration of thioacetamide (TAA), have been combined. Male Wistar rats were divided into four groups: 1 (control; n?=?10), 2 [triple partial portal vein ligation (TPVL); n?=?9], 3 (TAA; n?=?11), and 4 (TPVL plus TAA; n?=?9). After 3 months, portal pressure, types of portosystemic collateral circulation, laboratory hepatic function tests (aspartate aminotransferase, alanine aminotransferase, bilirubin, alkaline phosphatase, and gamma-glutamyl transpeptidase) and liver histology were studied. The animals belonging to group 2 (TPVL) developed extrahepatic portosystemic collateral circulation, associated with mesenteric venous vasculopathy without hepatic destructurization or portal hypertension. Animals from group 3 (TAA) developed cirrhosis and portal hypertension but not extrahepatic portosystemic collateral circulation, or mesenteric venous vasculopathy. Finally, the animals from group 4 (TPVL?+?TAA) developed cirrhosis, portal hypertension, portosystemic collateral circulation, and mesenteric venous vasculopathy. The association of TPVL and TAA can be used to obtain a model of chronic portal hypertension in the rat that includes all the alterations that patients with hepatic cirrhosis usually have. This could, therefore, prove to be a useful tool to study the pathophysiological mechanisms involved in these alterations.  相似文献   
999.
The authors present a case of amyloid infiltration involving the trigeminal nerve that mimicked a malignant cavernous sinus tumor with perineural tumor infiltration. A 64-year-old man presented with trigeminal nerve numbness. Imaging revealed a plaque-like enhancing lesion along the right lateral cavernous sinus extending anteriorly into Meckel's cave and involving the proximal V2 and V3 branches of the trigeminal nerve. The patient underwent an extradural frontotemporal craniotomy with middle fossa exposure of the cavernous sinus to diagnose and treat the presumed malignant cavernous sinus tumor. A reddish mass involving the lateral dural wall of the cavernous sinus was resected. The gasserian ganglion, V2, and V3, the latter of which was biopsied, were enlarged. Permanent histopathological studies showed microscopic eosinophilic, amorphous material, which stained positive for Congo red, and an absence of neoplastic cells. The final diagnosis was amyloidoma. Thus, amyloidomas can involve the trigeminal nerve or ganglia and should be considered in the differential diagnosis of a cavernous sinus lesion mimicking a tumor. Patients may have symptomatic improvement of trigeminal neuropathy with resection of the amyloidoma outside the nerve capsule that is compressing the nerve, while resection of the lesion from within the capsule may result in permanent trigeminal nerve dysfunction.  相似文献   
1000.
Apoptosis is a central physiological mechanism for maintaining cellular stability in tissue. Synovial fibroblasts, which play a central role in the pathogenesis of rheumatoid arthritis (RA), show a resistance to apoptosis. Several molecular mechanisms are involved in such resistance. Thus, soluble Fas can bind Fas ligands (Fas-L) and hinder Fas-L induced apoptosis in fibroblasts. SUMO-1 (a small ubiquitin-like modifier) attaches to proteins post-translationally. This appears to be significantly involved in apoptosis resistance in RA fibroblasts. SUMO-1 levels are substantially increased in synovial fibroblasts from RA patients. A change in the post-translational SUMOlation pattern could represent a new target for changing the stable activation of synovial fibroblasts in RA.  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