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   204850篇
  免费   3545篇
  国内免费   63篇
耳鼻咽喉   1384篇
儿科学   7609篇
妇产科学   3798篇
基础医学   20293篇
口腔科学   1992篇
临床医学   16503篇
内科学   36196篇
皮肤病学   1083篇
神经病学   19075篇
特种医学   9577篇
外国民族医学   1篇
外科学   32912篇
综合类   2830篇
一般理论   61篇
预防医学   21584篇
眼科学   3177篇
药学   11354篇
  1篇
中国医学   659篇
肿瘤学   18369篇
  2023年   319篇
  2022年   409篇
  2021年   1055篇
  2020年   675篇
  2019年   1066篇
  2018年   22888篇
  2017年   18073篇
  2016年   20168篇
  2015年   1837篇
  2014年   2056篇
  2013年   2488篇
  2012年   9372篇
  2011年   23306篇
  2010年   20032篇
  2009年   12563篇
  2008年   21278篇
  2007年   23534篇
  2006年   2254篇
  2005年   3816篇
  2004年   4854篇
  2003年   5638篇
  2002年   3679篇
  2001年   593篇
  2000年   675篇
  1999年   446篇
  1998年   469篇
  1997年   430篇
  1996年   267篇
  1995年   237篇
  1994年   220篇
  1993年   168篇
  1992年   241篇
  1991年   282篇
  1990年   294篇
  1989年   212篇
  1988年   190篇
  1987年   154篇
  1986年   166篇
  1985年   160篇
  1984年   124篇
  1983年   110篇
  1982年   90篇
  1980年   89篇
  1979年   89篇
  1978年   87篇
  1974年   77篇
  1973年   72篇
  1972年   71篇
  1968年   63篇
  1932年   63篇
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
1.
2.
Journal of Behavioral Medicine - Evidence supports the use of graphic warnings to educate the public about the health harms of smoking and suggests warnings eliciting negative emotional responses...  相似文献   
3.
4.

Background

There are well-established relationships between health and homelessness, and shelters can facilitate the transmission of diseases and contribute to their prevention. Adequate environmental health conditions and hygiene behaviors in homeless shelters are fundamental to the health of their clients, a marginalized population. We report the status of environmental health conditions and hygiene behaviors in homeless shelters and associated health outcomes; interventions to improve these conditions, behaviors, and outcomes; and obstacles to improvement.

Methods

PubMed, Web of Science, Scopus, and EBSCOhost were searched for peer-reviewed studies, and additional sources for grey literature. Studies were included if they reported primary data on one or more environmental health condition or hygiene behavior in homeless shelters.

Results

Twenty-eight studies were included in the review. Insufficient ventilation systems, unhygienic bedding, and overcrowding were the most documented environmental health and hygiene deficiencies in homeless shelters, and tuberculosis infections and skin diseases were the most documented associated health outcomes among clients. Studies frequently recommended or described implementation of behavioral and administrative controls, ventilation system improvements, and ultraviolet germicidal irradiation fixtures.

Discussion

Most studies addressed airborne transmission of tuberculosis and were conducted in high-income countries, revealing an imbalance in the literature. Insufficient resources and the transience of clients are barriers to improving hygiene behaviors and environmental conditions in homeless shelters. Further investment and research into ensuring adequate hygiene and environmental health in this setting can protect and promote the health and well-being of people experiencing homelessness.  相似文献   
5.
In 1998 Howard Parker, Judith Aldridge & Fiona Measham published Illegal Leisure, a ground‐breaking study of profound changes in British youth cultures in the 1990s, and the place of drugs and drug use in these upheavals. This work introduced the ‘normalization thesis’ to the social sciences, offering a novel vocabulary for re‐imagining the normative character of young people's attitudes towards and experiences of illicit drug use. Arriving at the dawn of the new century, the book offered a thoroughgoing re‐thinking of the character of youth cultures at a time of great social, cultural, economic and technological disruption. In so doing, the book deftly anticipated many of the most interesting currents of critical drug studies that followed.  相似文献   
6.
Owing to the frequent incidence of blast-induced traumatic brain injury (bTBI) in recent military conflicts, there is an urgent need to develop effective therapies for bTBI-related pathologies. Blood-brain barrier (BBB) breakdown has been reported to occur after primary blast exposure, making restoration of BBB function and integrity a promising therapeutic target. We tested the hypothesis that treatment with dexamethasone (DEX) after primary blast injury potentiates recovery of an in vitro BBB model consisting of mouse brain endothelial cells (bEnd.3). DEX treatment resulted in complete recovery of transendothelial electrical resistance and hydraulic conductivity 1 day after injury, compared with 3 days for vehicle-treated injured cultures. Administration of RU486 (mifepristone) inhibited effects of DEX, confirming that barrier restoration was mediated by glucocorticoid receptor signaling. Potentiated recovery with DEX treatment was accompanied by stronger zonula occludens (ZO)-1 tight junction immunostaining and expression, suggesting that increased ZO-1 expression was a structural correlate to BBB recovery after blast. Interestingly, augmented ZO-1 protein expression was associated with specific upregulation of the α+ isoform but not the α isoform. This is the first study to provide a mechanistic basis for potentiated functional recovery of an in vitro BBB model because of glucocorticoid treatment after primary blast injury.  相似文献   
7.
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation.  相似文献   
8.
9.
10.
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