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   4077篇
  免费   340篇
  国内免费   136篇
耳鼻咽喉   110篇
儿科学   110篇
妇产科学   47篇
基础医学   498篇
口腔科学   79篇
临床医学   396篇
内科学   646篇
皮肤病学   32篇
神经病学   292篇
特种医学   98篇
外科学   448篇
综合类   571篇
现状与发展   2篇
一般理论   1篇
预防医学   288篇
眼科学   120篇
药学   357篇
中国医学   149篇
肿瘤学   309篇
  2024年   8篇
  2023年   33篇
  2022年   91篇
  2021年   152篇
  2020年   93篇
  2019年   101篇
  2018年   94篇
  2017年   105篇
  2016年   103篇
  2015年   164篇
  2014年   193篇
  2013年   216篇
  2012年   298篇
  2011年   267篇
  2010年   228篇
  2009年   167篇
  2008年   198篇
  2007年   267篇
  2006年   219篇
  2005年   194篇
  2004年   162篇
  2003年   165篇
  2002年   168篇
  2001年   133篇
  2000年   120篇
  1999年   89篇
  1998年   41篇
  1997年   48篇
  1996年   29篇
  1995年   40篇
  1994年   31篇
  1993年   28篇
  1992年   54篇
  1991年   37篇
  1990年   31篇
  1989年   29篇
  1988年   30篇
  1987年   23篇
  1986年   12篇
  1985年   12篇
  1983年   6篇
  1982年   7篇
  1981年   5篇
  1980年   10篇
  1979年   6篇
  1978年   5篇
  1976年   6篇
  1975年   5篇
  1970年   4篇
  1968年   4篇
排序方式: 共有4553条查询结果,搜索用时 15 毫秒
1.
2.
Abstract

Cadmium (Cd) as environmental pollutant can induce severe damage, particularly to the testis. This study investigated the effects of Caffeic acid phenethyl ester (CAPE) on testicular dysfunction induced by Cd. Adult mice were intraperitoneally injected with cadmium chloride (CdCl2) with different doses of CAPE pretreatment. After CdCl2 injection, body/testis weight ratio decreased, Cd levels accumulated and zinc levels decreased in testis. Furthermore, Cd intoxication caused a significant increase of oxidative stress levels, antioxidant enzymes activities, and glutathione levels. Interestingly, significant improvements were observed after the administration of CAPE. Our results demonstrated the protective effect of CAPE, linking Cd testicular dysfunction to oxidative stress.  相似文献   
3.
INTRODUCTION The exact cause of Parkinson disease (PD) has not been known yet[1]. The overwhelming progress had been made in the treatment and pathogenesis of PD in recent 30 years, especially 10 years[2]. But it is still no way now to prevent or postpone…  相似文献   
4.
目的:运用软硬腭前移的手术方法扩大鼻咽下口,改善因鼻咽部狭小致阻塞性睡眠呼吸暂停综合征患者的呼吸暂停症状。方法:手术切除硬腭后份使其缩短、悬雍垂软腭成形并将软腭拉向前,扩大鼻咽下口。结果:患者术后自觉症状及客观评价疗效满意。结论:软硬腭前移鼻咽下口扩大显著改善鼻咽下口狭小导致的阻塞性睡眠呼吸暂停患者的症状。  相似文献   
5.
The clinical and ultrasonographic (US) features of 15 cases of mesenteric or omental cyst are herein described. This series included seven male and eight female patients, whose age ranged from 2–89 years. Correct clinical diagnosis was made in two children only, but preoperative US examination accurately demonstrated the lesion in 11 of 13 patients (85%). These cystic lesions usually had a thin wall, internal septations, and fluid content with sedimentation. Enteric duplication cysts had a relatively thick wall merging with the muscle layer of bowel loop, and multiloculation was noted mainly with cystic lymphangiomas or pseudocysts. The diagnostic and surgical management of these lesions are briefly reviewed and their US appearance is illustrated.  相似文献   
6.
7.
8.
Summary In order to investigate possible effects of smoking and drinking on the metabolism of toluence in occupational settings, 206 toluene-exposed men (mean age: 31.4 years) in shoemaking, painting, or surface-coating workshops together with 246 nonexposed control men (36.8 years) were studied for the time-weighted average intensities of exposure to toluene, hippuric acid concentration in shift-end urine samples, and the two social habits of smoking and drinking. The mean daily consumptions of cigarettes and ethanol were about 20 pieces and 10 g among smokers and drinkers, respectively. The geometric mean toluene concentration among the exposed subjects was about 20 ppm, with a maximum of 521 ppm. Regression analysis after classification of the subjects by smoking and drinking clearly demonstrated that the two social habits, when combined, markedly reduce the hippuric acid level in the urine of workers exposed to was a significant association between smoking and drinking habits, which hindered separate evaluation of the effects of the two habits on toluene metabolism. Comparison of the present results with the findings reported in the literature, however, suggested that the observed effects may be attributable to smoking rather than to drinking habits.  相似文献   
9.
Two triazaspirodienes, having similar phenoxy propyloxy side chain, were identified as potent mammalian dihydrofolate reductase inhibitors; one having a 6,5‐spiro bicyclic ring system (IC50 = 2.3 nm ) and the other a 6,6‐spiro bicyclic system (IC50 = 6.9 nm ). They also showed more than 50% antiproliferative activity against the MCF‐7 breast cancer cells at 20 μm . This study demonstrated the potential lead of the diamino‐triazaspirodienes in anticancer chemotherapeutical agents’ discovery.  相似文献   
10.
Impaired ability to conduct daily activities is a diagnostic criterion for dementia and a determinant of healthcare services utilization and caregiver burden. What predicts decline in instrumental activities of daily living (IADLs) is not well understood. This study examined measures of episodic memory, executive function, and MRI brain volumes in relation to baseline IADLs and as predictors of rate of IADL change. Participants were 124 elderly persons with cognitive function between normal and moderate dementia both with and without significant small vessel cerebrovascular disease. Random effects modeling showed that baseline memory and executive function (EXEC) were associated with baseline IADL scores, but only EXEC was independently associated with rate of change in IADLs. Whereas hippocampal and cortical gray matter volumes were significantly associated with baseline IADL scores, only hippocampal volume was associated with IADL change. In a model including cognitive and neuroimaging predictors, only EXEC independently predicted rate of decline in IADL scores. These findings indicate that greater executive dysfunction at initial assessment is associated with more rapid decline in IADLs. Perhaps executive function is particularly important with respect to maintaining IADLs. Alternatively, executive dysfunction may be a sentinel event indicating widespread cortical involvement and poor prognosis.  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