全文获取类型
收费全文 | 59941篇 |
免费 | 3329篇 |
国内免费 | 442篇 |
专业分类
耳鼻咽喉 | 583篇 |
儿科学 | 1140篇 |
妇产科学 | 1621篇 |
基础医学 | 7204篇 |
口腔科学 | 2049篇 |
临床医学 | 4941篇 |
内科学 | 15489篇 |
皮肤病学 | 1118篇 |
神经病学 | 5490篇 |
特种医学 | 1809篇 |
外科学 | 9176篇 |
综合类 | 352篇 |
现状与发展 | 1篇 |
一般理论 | 37篇 |
预防医学 | 3700篇 |
眼科学 | 1220篇 |
药学 | 3597篇 |
中国医学 | 139篇 |
肿瘤学 | 4046篇 |
出版年
2023年 | 426篇 |
2022年 | 690篇 |
2021年 | 2082篇 |
2020年 | 1091篇 |
2019年 | 1579篇 |
2018年 | 2080篇 |
2017年 | 1413篇 |
2016年 | 1517篇 |
2015年 | 1802篇 |
2014年 | 2459篇 |
2013年 | 3151篇 |
2012年 | 4905篇 |
2011年 | 4829篇 |
2010年 | 2703篇 |
2009年 | 2393篇 |
2008年 | 4037篇 |
2007年 | 4156篇 |
2006年 | 3884篇 |
2005年 | 3863篇 |
2004年 | 3432篇 |
2003年 | 3086篇 |
2002年 | 2743篇 |
2001年 | 395篇 |
2000年 | 260篇 |
1999年 | 391篇 |
1998年 | 495篇 |
1997年 | 422篇 |
1996年 | 371篇 |
1995年 | 356篇 |
1994年 | 278篇 |
1993年 | 218篇 |
1992年 | 197篇 |
1991年 | 144篇 |
1990年 | 146篇 |
1989年 | 128篇 |
1988年 | 100篇 |
1987年 | 92篇 |
1986年 | 98篇 |
1985年 | 91篇 |
1984年 | 107篇 |
1983年 | 94篇 |
1982年 | 119篇 |
1981年 | 105篇 |
1980年 | 104篇 |
1979年 | 50篇 |
1978年 | 64篇 |
1977年 | 52篇 |
1976年 | 50篇 |
1975年 | 41篇 |
1974年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
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
4.
Jose M. Morales Jose Angel Martinez-Flores Manuel Serrano Maria José Castro Francisco Javier Alfaro Florencio García Miguel Angel Martínez Amado Andrés Esther González Manuel Praga Estela Paz-Artal Antonio Serrano 《Journal of the American Society of Nephrology : JASN》2015,26(3):735-745
In the current immunosuppressive therapy era, vessel thrombosis is the most common cause of early graft loss after renal transplantation. The prevalence of IgA anti–β2-glycoprotein I antibodies (IgA-aB2GPI-ab) in patients on dialysis is elevated (>30%), and these antibodies correlate with mortality and cardiovascular morbidity. To evaluate the effect of IgA-aB2GPI-ab in patients with transplants, we followed all patients transplanted from 2000 to 2002 in the Hospital 12 de Octubre prospectively for 10 years. Presence of IgA-aB2GPI-ab in pretransplant serum was examined retrospectively. Of 269 patients, 89 patients were positive for IgA-aB2GPI-ab (33%; group 1), and the remaining patients were negative (67%; group 2). Graft loss at 6 months post-transplant was significantly higher in group 1 (10 of 89 versus 3 of 180 patients in group 2; P=0.002). The most frequent cause of graft loss was thrombosis of the vessels, which was observed only in group 1 (8 of 10 versus 0 of 3 patients in group 2; P=0.04). Multivariate analysis showed that the presence of IgA-aB2GPI-ab was an independent risk factor for early graft loss (P=0.04) and delayed graft function (P=0.04). There were no significant differences regarding patient survival between the two groups. Graft survival was similar in both groups after 6 months. In conclusion, patients with pretransplant IgA-aB2GPI-ab have a high risk of early graft loss caused by thrombosis and a high risk of delayed graft function. Therefore, pretransplant IgA-aB2GPI-ab may have a detrimental effect on early clinical outcomes after renal transplantation. 相似文献
5.
6.
Primary cutaneous anaplastic large cell lymphomas with 6p25.3 rearrangement exhibit particular histological features
下载免费PDF全文
![点击此处可从《Histopathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
7.
8.
9.
10.