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   23166篇
  免费   1358篇
  国内免费   110篇
耳鼻咽喉   89篇
儿科学   601篇
妇产科学   616篇
基础医学   1499篇
口腔科学   289篇
临床医学   3206篇
内科学   3871篇
皮肤病学   137篇
神经病学   1467篇
特种医学   716篇
外科学   3089篇
综合类   816篇
一般理论   4篇
预防医学   5638篇
眼科学   214篇
药学   1034篇
  11篇
中国医学   94篇
肿瘤学   1243篇
  2024年   51篇
  2023年   1621篇
  2022年   2234篇
  2021年   2125篇
  2020年   2458篇
  2019年   1283篇
  2018年   1099篇
  2017年   1152篇
  2016年   1155篇
  2015年   1041篇
  2014年   1999篇
  2013年   1343篇
  2012年   933篇
  2011年   584篇
  2010年   1008篇
  2009年   970篇
  2008年   424篇
  2007年   385篇
  2006年   339篇
  2005年   254篇
  2004年   169篇
  2003年   216篇
  2002年   223篇
  2001年   194篇
  2000年   149篇
  1999年   181篇
  1998年   167篇
  1997年   125篇
  1996年   140篇
  1995年   119篇
  1994年   85篇
  1993年   49篇
  1992年   38篇
  1991年   32篇
  1990年   40篇
  1989年   32篇
  1988年   56篇
  1987年   65篇
  1986年   66篇
  1985年   11篇
  1984年   7篇
  1983年   2篇
  1982年   4篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1973年   1篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
IntroductionWe examined the potential impact of banning tobacco displays and mandating plain packaging and cigarette advertisements at the point of sale (POS) on adult outcomes.MethodsA virtual convenience store was created with scenarios in which the tobacco product display was either fully visible (status quo) or enclosed behind a cabinet (display ban), and cigarette packs and advertisements were either in full color (status quo) or black and white, text only (plain). A national convenience sample of 1313 adult current smokers and recent quitters was randomized to 1 of 4 conditions and given a shopping task to complete in the virtual store. Main outcomes were participants' self-reported urge to smoke and tobacco purchase attempts in the virtual store.ResultsCompared with recent quitters in the status quo conditions, recent quitters in the display ban condition had lower urges to smoke (β =  4.82, 95% CI =  8.16–− 1.49, p < 0.01). Compared with current smokers in the status quo conditions, smokers in the display ban conditions were less likely to attempt to purchase cigarettes in the virtual store (OR = 0.05, 95% CI = 0.03–0.08, P < 0.01). Smokers exposed to plain packs and ads were significantly less likely to attempt to purchase cigarettes (OR = 0.31, 95% CI = 0.20–0.47, P < 0.01) than those exposed to color packs and ads.ConclusionsPolicies that ban the display of tobacco products or require plain packaging and advertising at the POS may help reduce adult smoking.  相似文献   
102.
103.
104.
105.
Contributors     
《Cardiology Clinics》2019,37(1):iii-iv
  相似文献   
106.
IntroductionMost young people experiencing homelessness smoke cigarettes, but little is known about use of alternative tobacco products (ATPs) such as e-cigarettes or other electronic nicotine delivery systems (ENDS) and little cigars/cigarillos (LCCs). This study examines past month use and correlates of cigarettes and ATP among young tobacco users experiencing homelessness.MethodsWe surveyed a probability sample of N = 469 unaccompanied homeless 13–25 year olds (mean age = 22; 71% male), who reported past month use of any type of tobacco product, from 25 service and street sites in Los Angeles County.ResultsNearly all (90%) participants reported smoking regular cigarettes, and 78% reported using at least one tobacco product other than regular cigarettes. The most commonly used of these other products was natural cigarettes (55%), followed by LCCs (43%), ENDS (34%), cigars (31%), hookah (14%), chewing tobacco (7%), and snus (5%). Multivariable models indicated that correlates of past month use differed by product, but included sociodemographic characteristics, homelessness severity, depression, exposure to other people who used the product, and product perceptions (e.g., relative access, cost, and harm compared to cigarettes).ConclusionUse of cigarettes and ATPs are both widespread among young homeless tobacco users, suggesting that efforts to reduce tobacco use in this population should have a broad focus that includes a variety of products. The effectiveness of these efforts may be enhanced by addressing their considerable exposure to other tobacco users, as well as their perceptions of certain products as being less harmful or more cost-effective options than regular cigarettes.  相似文献   
107.
目的:探讨lncRNA RP11-86H7.1在川崎病(KD)患者血清中的表达及其与临床病理特征及预后的关系。方法:筛选KD特异相关的循环lncRNA,分KD治疗前患儿组、KD治疗后患儿组、普通发热患儿组及健康儿童组,采用qPCR检测各组血清lncRNA RP11-86H7.1相对表达。分析血清lncRNA RP11-86H7.1相对表达与KD临床病理特征间关系;绘制ROC曲线,分析血清lncRNA RP11-86H7.1表达水平对KD的诊断效能。结果:KD急性患儿组血清lncRNA RP11-86H7.1相对表达量高于各对照组(P<0.05);年龄和性别比例与低表达组比较差异无统计学意义(P>0.05);qPCR发现lncRNA RP11-86H7.1在KD急性期患儿血清中表达水平明显高于KD恢复期、健康儿童及发热儿童组,差异均有统计学意义(P<0.05)。结论:血清lncRNA RP11-86H7.1在KD患者中表达上调,其可作为KD早期诊断和评估预后的潜在的生物标志物。  相似文献   
108.
IntroductionCentral venous catheter applications and complications are closely related to the tip position. Previous studies have reported some rare cases of catheter misplacement. Here, we report a case of misplacement of a peripherally inserted central catheter into the lateral thoracic vein.Case reportA 56-year-old cancer patient underwent placement of a peripherally inserted central catheter through the left basilic vein under ultrasound-guided puncture. The catheterisation procedure was uneventful, so the catheter was believed to be in the superior vena cava. However, the post-anterior chest X-ray image revealed that after the catheter advanced towards the axilla, it turned downwards and outwards in the direction of the left lateral thoracic region, with the projection of the catheter tip giving the appearance of termination in the subcutaneous tissue of the lateral thoracic wall on the two-dimensional image. The catheter was then repositioned in the distal superior vena cava.DiscussionPeripherally inserted central catheters can be potentially misplaced into the lateral thoracic vein because these catheters can pass through the orifice of the lateral thoracic vein which flows into the axillary vein. Some pathological cases and clinical conditions can cause dilatation of the lateral thoracic vein, which increases the probability of catheter misplacement. Three principles were proposed to avoid this rare complication: a comprehensive review of the patients’ medical history, real-time image-guided catheterisation and routine radiographic identification of the tip position.  相似文献   
109.
110.
何敏  黄燕 《现代预防医学》2020,(23):4381-4384
目的 肺癌是全球发病率及死亡率最高的恶性肿瘤,患者5年生存率仍低于20%,提高早期诊断及筛查至关重要,本文对肺癌早期诊断方法进行文献综述。方法 检索PubMed、知网、万方、维普等数据库,选择与肺癌筛查相关的文献,进一步选择如CT、核磁共振、MiRNA、自身抗体等文献,提炼其相关结果结论。结果 肺癌早期诊断方法较多,每一种诊断方法均有其优缺点。结论 目前尚无任何一种技术被证实能独立完成早期肺癌的筛查,需要将目前早期诊断技术加以优化组合,以提高早期肺癌的诊断率。  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