全文获取类型
收费全文 | 24290篇 |
免费 | 1743篇 |
国内免费 | 135篇 |
专业分类
耳鼻咽喉 | 184篇 |
儿科学 | 624篇 |
妇产科学 | 625篇 |
基础医学 | 3047篇 |
口腔科学 | 617篇 |
临床医学 | 2356篇 |
内科学 | 4868篇 |
皮肤病学 | 263篇 |
神经病学 | 2097篇 |
特种医学 | 916篇 |
外科学 | 3852篇 |
综合类 | 351篇 |
现状与发展 | 1篇 |
一般理论 | 38篇 |
预防医学 | 1757篇 |
眼科学 | 855篇 |
药学 | 1665篇 |
中国医学 | 56篇 |
肿瘤学 | 1996篇 |
出版年
2024年 | 26篇 |
2023年 | 202篇 |
2022年 | 364篇 |
2021年 | 835篇 |
2020年 | 449篇 |
2019年 | 647篇 |
2018年 | 784篇 |
2017年 | 529篇 |
2016年 | 595篇 |
2015年 | 742篇 |
2014年 | 1002篇 |
2013年 | 1144篇 |
2012年 | 1834篇 |
2011年 | 1884篇 |
2010年 | 1071篇 |
2009年 | 996篇 |
2008年 | 1542篇 |
2007年 | 1597篇 |
2006年 | 1510篇 |
2005年 | 1465篇 |
2004年 | 1276篇 |
2003年 | 1146篇 |
2002年 | 980篇 |
2001年 | 422篇 |
2000年 | 330篇 |
1999年 | 310篇 |
1998年 | 199篇 |
1997年 | 166篇 |
1996年 | 142篇 |
1995年 | 115篇 |
1994年 | 108篇 |
1993年 | 92篇 |
1992年 | 168篇 |
1991年 | 142篇 |
1990年 | 144篇 |
1989年 | 139篇 |
1988年 | 102篇 |
1987年 | 103篇 |
1986年 | 86篇 |
1985年 | 76篇 |
1984年 | 75篇 |
1983年 | 67篇 |
1982年 | 53篇 |
1981年 | 65篇 |
1980年 | 55篇 |
1979年 | 34篇 |
1978年 | 34篇 |
1977年 | 38篇 |
1976年 | 31篇 |
1975年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
N. Cody Schaal Raushan A. Salaam Michael Stevens Alex Stubner 《Journal of occupational and environmental hygiene》2019,16(5):329-335
The purpose of this investigation was to characterize noise levels in spaces designated as “effective quiet” areas on a U.S. Navy aircraft carrier. Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. Equivalent sound level (Leq) measurements were collected during flight operations (Leq (flt ops)), non-flight operations (Leq (non-flt ops)), and over 24-hr periods (Leq (24-hr)). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH®) Threshold Limit Value (TLV®) for “effective quiet” areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24?hr. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The Leq measurements in decibels “A” weighted (dBA) were compared to determine significant differences between Leq (flt ops), Leq (non-flt ops), and Leq (24-hr) and were compared between leisure area and berthing area. Measured noise levels according to time period ranged as follows: (1) Leq (24-hr): 70.8–105.4 dBA; (2) Leq (flt ops): 70–101.2 dBA; and (3) Leq (non-flt ops): 39.4–104.6 dBA. All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the “effective quiet” 70 dBA ACGIH TLV. Mean Leqs were 15 dBA higher during flight operations compared to non-flight operations in “effective quiet” areas (p?=?0.001). The Leqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p?=?0.001). Results suggest noise levels in “effective quiet” areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty. 相似文献
2.
A mixed‐method study of effects of a therapeutic play intervention for children on parental anxiety and parents' perceptions of the intervention 下载免费PDF全文
3.
PNPLA3 gene polymorphism and response to lifestyle modification in patients with nonalcoholic fatty liver disease 下载免费PDF全文
4.
5.
6.
Danail Hristozov Alex Zabeo Keld Alstrup Jensen Stefania Gottardo Panagiotis Isigonis Laura Maccalman 《Nanotoxicology》2016,10(9):1215-1228
Several tools to facilitate the risk assessment and management of manufactured nanomaterials (MN) have been developed. Most of them require input data on physicochemical properties, toxicity and scenario-specific exposure information. However, such data are yet not readily available, and tools that can handle data gaps in a structured way to ensure transparent risk analysis for industrial and regulatory decision making are needed. This paper proposes such a quantitative risk prioritisation tool, based on a multi-criteria decision analysis algorithm, which combines advanced exposure and dose-response modelling to calculate margins of exposure (MoE) for a number of MN in order to rank their occupational risks. We demonstrated the tool in a number of workplace exposure scenarios (ES) involving the production and handling of nanoscale titanium dioxide, zinc oxide (ZnO), silver and multi-walled carbon nanotubes. The results of this application demonstrated that bag/bin filling, manual un/loading and dumping of large amounts of dry powders led to high emissions, which resulted in high risk associated with these ES. The ZnO MN revealed considerable hazard potential in vivo, which significantly influenced the risk prioritisation results. In order to study how variations in the input data affect our results, we performed probabilistic Monte Carlo sensitivity/uncertainty analysis, which demonstrated that the performance of the proposed model is stable against changes in the exposure and hazard input variables. 相似文献
7.
8.
9.
Amy Y. Zhang Christopher Burant Alex Z. Fu Gerald Strauss Donald R. Bodner Lee Ponsky 《Journal of psychosocial oncology》2020,38(2):210-227
AbstractPurpose: We examined underlying psychosocial processes of a behavioral treatment for urinary incontinence (UI) of prostate cancer survivors.Design: Secondary analysis of data collected from a clinical trial.Sample: Two hundred forty-four prostate cancer survivors who participated in a clinical trial of behavioral intervention to UI as intervention or control subjects.Methods: The participants had a 3-month behavioral intervention or usual care and were followed up for an additional 3?months. They were assessed at baseline, 3, and 6?months. Latent growth curve models were performed to examine trajectories of each study variable and relationships among the variables.Findings: Increasing self-efficacy and social support were significantly and independently associated with more reduction of urinary leakage frequency over time.Implications for psychosocial oncology: Providing problem-solving skills and social support, including peer support, are essential for empowering patients to reduce UI. 相似文献
10.
Prevalence of Potentially Inappropriate Prescribing Among Hong Kong Older Adults: A Comparison of the Beers 2003, Beers 2012, and Screening Tool of Older Person's Prescriptions and Screening Tool to Alert doctors to Right Treatment Criteria 下载免费PDF全文