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   64727篇
  免费   9617篇
  国内免费   175篇
耳鼻咽喉   779篇
儿科学   2206篇
妇产科学   1685篇
基础医学   6288篇
口腔科学   1785篇
临床医学   12207篇
内科学   12520篇
皮肤病学   1535篇
神经病学   7097篇
特种医学   1451篇
外科学   7316篇
综合类   417篇
现状与发展   3篇
一般理论   86篇
预防医学   9326篇
眼科学   1166篇
药学   3551篇
中国医学   60篇
肿瘤学   5041篇
  2024年   272篇
  2023年   1760篇
  2022年   1098篇
  2021年   2410篇
  2020年   2168篇
  2019年   2210篇
  2018年   3308篇
  2017年   3041篇
  2016年   3091篇
  2015年   3212篇
  2014年   4097篇
  2013年   4742篇
  2012年   5050篇
  2011年   4992篇
  2010年   3433篇
  2009年   3386篇
  2008年   3907篇
  2007年   3678篇
  2006年   3544篇
  2005年   3166篇
  2004年   2716篇
  2003年   2288篇
  2002年   1986篇
  2001年   479篇
  2000年   259篇
  1999年   435篇
  1998年   572篇
  1997年   503篇
  1996年   461篇
  1995年   401篇
  1994年   269篇
  1993年   241篇
  1992年   172篇
  1991年   131篇
  1990年   114篇
  1989年   136篇
  1988年   101篇
  1987年   77篇
  1986年   68篇
  1985年   69篇
  1984年   71篇
  1983年   60篇
  1982年   37篇
  1981年   38篇
  1980年   36篇
  1978年   33篇
  1977年   24篇
  1976年   22篇
  1975年   24篇
  1973年   22篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
31.
To better understand the potential environmental health risk presented by West Nile virus (WNV)-contaminated feces, we quantified the amount of WNV present in the feces of experimentally infected American crows (Corvus brachyrhynchos) and fish crows (Corvus ossifragus). Peak fecal titers ranged from 10(3.5) to 10(8.8) plaque-forming units (PFU)/g for 10 American crows and from 10(2.3) to 10(6.4) PFU/g for 10 fish crows. The presence of infectious WNV in bird feces indicates a potential for direct transmission of WNV. Thus, handlers of sick or dead birds should take appropriate precautions to avoid exposure to fecal material.  相似文献   
32.
33.
The Enhancing Patient Prenatal Education study tested the feasibility and educational impact of an interactive program for patient prenatal genetic screening and testing education. Patients at two private practices and one public health clinic participated (N = 207). The program collected knowledge and measures of anxiety before and after use of the tool. Time in various prenatal visit activities was collected prior to and after the introduction of the education tool. Providers completed an assessment of their experiences with patients who had used the program. Results indicate that patient knowledge significantly increased from pre to post (p = .0001) with no increase in anxiety (p = .31). Time in clinic activities, including overall visit time, increased. A majority of providers indicated that the program disrupted clinic flow. This assessment suggests that the program increases patient knowledge and does not increase patient anxiety. However, challenges remain to using this program in a clinic setting.  相似文献   
34.
The purpose of this study was to determine the dosimetric impact of a neurosurgical titanium mesh in patients treated with 6- and 18-MV photon beams. The effects of a 0.4-mm-thick titanium mesh on the dose profile at 3 regions within a solid water phantom were measured using extended dose range-2 (EDR2) film for 6- and 18-MV photon beams. All measurements were performed with the titanium mesh placed at a depth of 1.5 cm in the phantom. Films were exposed immediately above the mesh, immediately below the mesh, and at a depth of 5 cm from the surface of the phantom. The films were scanned using a scanning densitometer. In the region directly above the titanium mesh, there was an increase in dose of 7.1% for 6-MV photons and 4.9% for 18-MV photons. Directly below the titanium mesh, there was an average decrease in dose of 1.5% for 6-MV photons and an increase of 1.0% for 18-MV photons. At 5-cm depth, for 6- and 18-MV photons, there was a decrease in dose of 2.2% and 0.6%, respectively. We concluded that for cranial irradiation with high-energy photons, the dosimetric impact of a 0.4-mm titanium mesh is small and does not require modification in treatment parameters.  相似文献   
35.
36.
Balanced analgesia (an opioid and a nonsteroidal anti-inflammatory agent) after hysterectomy often leads to better postoperative pain outcomes. Researchers compared post-hysterectomy patients who received balanced analgesia with those who received only morphine patient-controlled analgesia, and their relationship with pain scores, ambulation, and hospital length of stay.  相似文献   
37.
Associations between street connectivity and active transportation   总被引:1,自引:0,他引:1  

Background  

Past studies of associations between measures of the built environment, particularly street connectivity, and active transportation (AT) or leisure walking/bicycling have largely failed to account for spatial autocorrelation of connectivity variables and have seldom examined both the propensity for AT and its duration in a coherent fashion. Such efforts could improve our understanding of the spatial and behavioral aspects of AT. We analyzed spatially identified data from Los Angeles and San Diego Counties collected as part of the 2001 California Health Interview Survey.  相似文献   
38.
39.

Background  

Exercise has been recommended for improving global-well being in adults with fibromyalgia. However, no meta-analysis has determined the effects of exercise on global well-being using a single instrument and when analyzed separately according to intention-to-treat and per-protocol analyses. The purpose of this study was to fill that gap.  相似文献   
40.
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