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   27680篇
  免费   2580篇
  国内免费   1048篇
耳鼻咽喉   265篇
儿科学   427篇
妇产科学   287篇
基础医学   3156篇
口腔科学   416篇
临床医学   2985篇
内科学   4827篇
皮肤病学   560篇
神经病学   1407篇
特种医学   1139篇
外国民族医学   1篇
外科学   3973篇
综合类   3166篇
现状与发展   3篇
一般理论   4篇
预防医学   2405篇
眼科学   763篇
药学   2635篇
  16篇
中国医学   868篇
肿瘤学   2005篇
  2024年   35篇
  2023年   246篇
  2022年   583篇
  2021年   1233篇
  2020年   844篇
  2019年   857篇
  2018年   985篇
  2017年   785篇
  2016年   840篇
  2015年   1028篇
  2014年   1304篇
  2013年   1361篇
  2012年   2022篇
  2011年   2012篇
  2010年   1390篇
  2009年   1237篇
  2008年   1637篇
  2007年   1700篇
  2006年   1507篇
  2005年   1300篇
  2004年   1377篇
  2003年   1418篇
  2002年   1260篇
  2001年   1031篇
  2000年   806篇
  1999年   528篇
  1998年   214篇
  1997年   203篇
  1996年   141篇
  1995年   115篇
  1994年   108篇
  1993年   92篇
  1992年   176篇
  1991年   128篇
  1990年   135篇
  1989年   119篇
  1988年   107篇
  1987年   84篇
  1986年   73篇
  1985年   55篇
  1984年   49篇
  1983年   35篇
  1982年   26篇
  1981年   14篇
  1980年   16篇
  1979年   18篇
  1977年   10篇
  1976年   8篇
  1975年   7篇
  1974年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Among the chief limitations in achieving early detection and control of animal‐origin influenza of pandemic potential in high‐risk livestock populations is the existing lag time between sample collection and diagnostic result. Advances in molecular diagnostics are permitting deployment of affordable, rapid, highly sensitive, and specific point‐of‐capture assays, providing opportunities for targeted surveillance driving containment strategies with potentially compelling returns on investment. Interrupting disease transmission at source holds promise of disrupting cycles of animal‐origin influenza incursion to endemicity and limiting impact on animal production, food security, and public health. Adoption of new point‐of‐capture diagnostics should be undertaken in the context of promoting robust veterinary services systems and parallel support for operationalizing pre‐authorized plans and communication strategies that will ensure that the full potential of these new platforms is realized.  相似文献   
4.
陈海  杨黎  王晓华 《医学综述》2016,(4):778-781
目的研究葛根素联合复方樟柳碱注射液对眼底病患者的治疗效果及对血液流变学指标的影响。方法选择2013年4月至2014年4月在绵阳市第三人民医院眼科进行眼底病治疗的患者100例,并按入院顺序抽签随机分为观察组和对照组,各50例。对照组进行葛根素常规治疗(葛根素注射液0.4 g加入生理盐水250 m L中静脉滴注,每日1次,1个疗程14 d,1个疗程后停药3 d,再进行下一疗程),观察组在此基础上联合复方樟柳碱注射液进行治疗(采用复方樟柳碱2 m L在患者颞浅动脉旁行皮下注射,每日1次,1个疗程14 d,完成1个疗程后停药3 d,再换肾俞穴进行注射,1个疗程后停药3 d,再进行第一个疗程的用药)。3个疗程后,比较两组患者治疗前后血液流变学的变化、术后复发率和不良反应情况及患者的治疗效果。结果治疗后,观察组全血黏度为(4.82±0.41)m Pa·s明显低于对照组的(5.56±0.39)m Pa·s,红细胞聚集指数(3.80±0.41)明显低于对照组(4.77±0.55),纤维蛋白原(4.20±0.24)g/L明显低于对照组(5.25±0.43)g/L,差异均有统计学意义(t=9.247,9.998,15.077,P<0.01);观察组患者治疗后复发率为2.0%(1/50),不良反应的总发生率为4.0%(2/50),分别低于对照组14.0%(7/50)和18.0%(9/50)(P<0.01);观察组患者的总有效率为98.0%(49/50),显著高于对照组的82.0%(41/50)(P<0.05)。结论葛根素和复方樟柳碱注射液联合治疗眼底病患者,可改善患者血液流变学,并提高临床治疗效果。  相似文献   
5.
6.
Genetic and epigenetic alterations importantly contribute to the pathogenesis of lung cancer. In the study, we measured the frequency and distribution of molecular abnormalities of EGFR as well as the aberrant promoter methylations of BRCA1, MGMT, MLH1, and RASSF1A in Vietnamese lung adenocarcinomas. We investigated the association between genetic and epigenetic alteration, and between each abnormality with clinicopathologic parameters. Somatic EGFR mutation that was found in 49/139 (35.3%) lung adenocarcinomas showed a significant association with young age, female gender, and non-smokers. EGFR overexpression was identified in 82 tumors (59.0%) and statistical relationships with EGFR or BRCA1 methylation but not EGFR mutation. In addition, EGFR, BRCA1, MGMT, MLH1, and RASSF1A methylations were found in 33 (23.7%), 41 (29.5%), 46 (33.1%), 28 (20.1%), and 41 (29.5%) cases of a total of 139 lung adenocarcinomas, respectively. The RASSF1A methylation was found to be linked to the smoking habit. Methylations in MGMT and RASSF1A were also found to correlate with metastasis status. Furthermore, the distribution of EGFR mutation and that of BRCA1, MGMT or RASSF1A methylation were significantly exclusive in lung adenocarcinomas. The main finding of our study demonstrate that epigenetic abnormalities might play a critical role for the lung tumorigenesis in patients with smoking history and metastasis, and partly affect the predictive value of EGFR mutations through blocking expression due to promoter EGFR hypermethylation. Mutually exclusive distribution of genetic and epigenetic alterations reflects differently biological characteristics in the etiology of lung adenocarcinomas.  相似文献   
7.
8.
9.
HIV risk in vulnerable groups such as itinerant male street labourers is often examined via a focus on individual determinants. This study provides a test of a modified Information-Motivation-Behavioral Skills (IMB) model to predict condom use behaviour among male street workers in urban Vietnam. In a cross-sectional survey using a social mapping technique, 450 male street labourers from 13 districts of Hanoi, Vietnam were recruited and interviewed. Collected data were first examined for completeness; structural equation modelling was then employed to test the model fit. Condoms were used inconsistently by many of these men, and usage varied in relation to a number of factors. A modified IMB model had a better fit than the original IMB model in predicting condom use behaviour. This modified model accounted for 49% of the variance, versus 10% by the original version. In the modified model, the influence of psychosocial factors was moderately high, whilst the influence of HIV prevention information, motivation and perceived behavioural skills was moderately low, explaining in part the limited level of condom use behaviour. This study provides insights into social factors that should be taken into account in public health planning to promote safer sexual behaviour among Asian male street labourers.  相似文献   
10.
线粒体脑肌病属于罕见性母系遗传病,本文回顾性分析了1家4例高乳酸血症-卒中样发作综合征(MELAS)型线粒体脑肌病患者,其主要表现为卒中样发作、头痛、癫痫、高乳酸血症、肌肉不耐受疲劳、高级智能下降、听力下降和身材矮小等,结合特征性影像学变化、基因检测及肌肉活检明确诊断,并结合文献对只有女儿能将其线粒体DNA(mt-DNA)传递给下一代的母系遗传MELAS型线粒体脑肌病临床特点进行了总结分析,旨在帮助临床认识此病,进一步提高MELAS型线粒体脑肌病的临床诊断率。  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