全文获取类型
收费全文 | 61087篇 |
免费 | 5109篇 |
国内免费 | 282篇 |
专业分类
耳鼻咽喉 | 727篇 |
儿科学 | 1922篇 |
妇产科学 | 1242篇 |
基础医学 | 7497篇 |
口腔科学 | 1375篇 |
临床医学 | 5961篇 |
内科学 | 12618篇 |
皮肤病学 | 865篇 |
神经病学 | 5440篇 |
特种医学 | 2311篇 |
外科学 | 9119篇 |
综合类 | 1379篇 |
一般理论 | 34篇 |
预防医学 | 5079篇 |
眼科学 | 2291篇 |
药学 | 4250篇 |
1篇 | |
中国医学 | 174篇 |
肿瘤学 | 4193篇 |
出版年
2022年 | 434篇 |
2021年 | 1036篇 |
2020年 | 700篇 |
2019年 | 1019篇 |
2018年 | 1157篇 |
2017年 | 852篇 |
2016年 | 992篇 |
2015年 | 1203篇 |
2014年 | 1735篇 |
2013年 | 2459篇 |
2012年 | 3575篇 |
2011年 | 3867篇 |
2010年 | 2184篇 |
2009年 | 1988篇 |
2008年 | 3481篇 |
2007年 | 3675篇 |
2006年 | 3570篇 |
2005年 | 3530篇 |
2004年 | 3423篇 |
2003年 | 3235篇 |
2002年 | 3150篇 |
2001年 | 1407篇 |
2000年 | 1236篇 |
1999年 | 1221篇 |
1998年 | 750篇 |
1997年 | 602篇 |
1996年 | 553篇 |
1995年 | 535篇 |
1994年 | 504篇 |
1993年 | 462篇 |
1992年 | 746篇 |
1991年 | 689篇 |
1990年 | 625篇 |
1989年 | 617篇 |
1988年 | 581篇 |
1987年 | 554篇 |
1986年 | 548篇 |
1985年 | 566篇 |
1984年 | 540篇 |
1983年 | 521篇 |
1982年 | 592篇 |
1981年 | 526篇 |
1980年 | 533篇 |
1979年 | 398篇 |
1978年 | 333篇 |
1977年 | 362篇 |
1976年 | 260篇 |
1975年 | 256篇 |
1974年 | 292篇 |
1973年 | 271篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
1.
2.
3.
Michelle Moffa Ryan Cronk Donald Fejfar Sarah Dancausse Leslie Acosta Padilla Jamie Bartram 《International journal of hygiene and environmental health》2019,222(3):335-346
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4.
Danielle E Whittier Elizabeth J Samelson Marian T Hannan Lauren A Burt David A Hanley Emmanuel Biver Pawel Szulc Elisabeth Sornay-Rendu Blandine Merle Roland Chapurlat Eric Lespessailles Andy Kin On Wong David Goltzman Sundeep Khosla Serge Ferrari Mary L Bouxsein Douglas P Kiel Steven K Boyd 《Journal of bone and mineral research》2022,37(3):428-439
Prevalence of osteoporosis is more than 50% in older adults, yet current clinical methods for diagnosis that rely on areal bone mineral density (aBMD) fail to detect most individuals who have a fragility fracture. Bone fragility can manifest in different forms, and a “one-size-fits-all” approach to diagnosis and management of osteoporosis may not be suitable. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides additive information by capturing information about volumetric density and microarchitecture, but interpretation is challenging because of the complex interactions between the numerous properties measured. In this study, we propose that there are common combinations of bone properties, referred to as phenotypes, that are predisposed to different levels of fracture risk. Using HR-pQCT data from a multinational cohort (n = 5873, 71% female) between 40 and 96 years of age, we employed fuzzy c-means clustering, an unsupervised machine-learning method, to identify phenotypes of bone microarchitecture. Three clusters were identified, and using partial correlation analysis of HR-pQCT parameters, we characterized the clusters as low density, low volume, and healthy bone phenotypes. Most males were associated with the healthy bone phenotype, whereas females were more often associated with the low volume or low density bone phenotypes. Each phenotype had a significantly different cumulative hazard of major osteoporotic fracture (MOF) and of any incident osteoporotic fracture (p < 0.05). After adjustment for covariates (cohort, sex, and age), the low density followed by the low volume phenotype had the highest association with MOF (hazard ratio = 2.96 and 2.35, respectively), and significant associations were maintained when additionally adjusted for femoral neck aBMD (hazard ratio = 1.69 and 1.90, respectively). Further, within each phenotype, different imaging biomarkers of fracture were identified. These findings suggest that osteoporotic fracture risk is associated with bone phenotypes that capture key features of bone deterioration that are not distinguishable by aBMD. © 2021 American Society for Bone and Mineral Research (ASBMR). 相似文献
5.
Xin Yi Wong Andrew Qi Jun Lim Qianyu Shen John Whay Kuang Chia Min Hoe Chew Wah Siew Tan 《Current medical research and opinion》2020,36(10):1677-1686
Abstract
Objective
Ras wild-type metastatic colorectal cancers (mCRC) may be treated with anti-vascular endothelial growth factor (VEGF) or anti-epidermal growth factor receptor (EGFR) agents. We aim to estimate patients’ preferences for mCRC treatment and relative importance of cost, efficacy improvement, avoidance of side effects and therapy convenience, and relative uptake between profiles that resemble Bevacizumab (anti-VEGF) and Cetuximab (anti-EGFR), two commonly prescribed mCRC targeted therapies. 相似文献6.
7.
8.
PNPLA3 gene polymorphism and response to lifestyle modification in patients with nonalcoholic fatty liver disease
下载免费PDF全文
![点击此处可从《Journal of gastroenterology and hepatology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
9.
Tien‐Yao Tsai Iat‐Lon Leong Ka‐Shun Cheng Lian‐Ru Shiao Tzu‐Hui Su Kar‐Lok Wong Paul Chan Yuk‐Man Leung 《Fundamental & clinical pharmacology》2019,33(1):52-62
A pathological feature in atherosclerosis is the dysfunction and death of vascular endothelial cells (EC). Oxidized low‐density lipoprotein (LDL), known to accumulate in the atherosclerotic arterial walls, impairs endothelium‐dependent relaxation and causes EC apoptosis. A major bioactive ingredient of the oxidized LDL is lysophosphatidylcholine (LPC), which at higher concentrations causes apoptosis and necrosis in various EC. There is hitherto no report on LPC‐induced cytotoxicity in brain EC. In this work, we found that LPC caused cytosolic Ca2+ overload, mitochondrial membrane potential decrease, p38 activation, caspase 3 activation and eventually apoptotic death in mouse cerebral bEND.3 EC. In contrast to reported reactive oxygen species (ROS) generation by LPC in other EC, LPC did not trigger ROS formation in bEND.3 cells. Pharmacological inhibition of p38 alleviated LPC‐inflicted cell death. We examined whether heparin could be cytoprotective: although it could not suppress LPC‐triggered Ca2+ signal, p38 activation and mitochondrial membrane potential drop, it did suppress LPC‐induced caspase 3 activation and alleviate LPC‐inflicted cytotoxicity. Our data suggest LPC apoptotic death mechanisms in bEND.3 might involve mitochondrial membrane potential decrease and p38 activation. Heparin is protective against LPC cytotoxicity and might intervene steps between mitochondrial membrane potential drop/p38 activation and caspase 3 activation. 相似文献
10.