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   6489篇
  免费   535篇
  国内免费   19篇
耳鼻咽喉   70篇
儿科学   198篇
妇产科学   190篇
基础医学   887篇
口腔科学   78篇
临床医学   844篇
内科学   1214篇
皮肤病学   115篇
神经病学   678篇
特种医学   309篇
外科学   697篇
综合类   48篇
一般理论   5篇
预防医学   725篇
眼科学   128篇
药学   399篇
中国医学   3篇
肿瘤学   455篇
  2024年   26篇
  2023年   140篇
  2022年   195篇
  2021年   450篇
  2020年   258篇
  2019年   355篇
  2018年   335篇
  2017年   264篇
  2016年   292篇
  2015年   261篇
  2014年   341篇
  2013年   400篇
  2012年   505篇
  2011年   531篇
  2010年   276篇
  2009年   226篇
  2008年   338篇
  2007年   301篇
  2006年   288篇
  2005年   245篇
  2004年   201篇
  2003年   219篇
  2002年   177篇
  2001年   52篇
  2000年   35篇
  1999年   39篇
  1998年   32篇
  1997年   17篇
  1996年   16篇
  1995年   11篇
  1994年   14篇
  1993年   10篇
  1992年   16篇
  1991年   22篇
  1990年   23篇
  1989年   17篇
  1988年   26篇
  1987年   12篇
  1986年   11篇
  1985年   20篇
  1984年   10篇
  1983年   2篇
  1981年   2篇
  1980年   3篇
  1979年   4篇
  1978年   2篇
  1972年   2篇
  1971年   5篇
  1970年   2篇
  1965年   5篇
排序方式: 共有7043条查询结果,搜索用时 9 毫秒
1.
2.
3.
Abstract – Aim: To evaluate the pulp and periodontal healing of laterally luxated permanent teeth. Material and methods: Patients presenting with lateral luxation of permanent teeth during 2001–2002 were enrolled in this clinical study. Laterally luxated teeth were repositioned and splinted with a TTS/composite resin splint for 4 weeks. Immediate (prophylactic) root‐canal treatment was performed in severely luxated teeth with radiographically closed apices. All patients received tetracycline for 10 days. Re‐examinations were performed after 1, 2, 3, 6, 12 and 48 months. Results: All 47 laterally luxated permanent teeth that could be followed over the entire study period survived. In 10 teeth (21.3%), a prophylactic root‐canal treatment was performed within 2 weeks following injury. The remaining 37 teeth showed the following characteristics at the 4‐year re‐examination: 19 teeth (51.4%) had pulp survival (no clinical or radiographic signs or symptoms), nine teeth (24.3%) presented with pulp canal calcification, and pulp necrosis was seen in another nine teeth (24.3%), within the first year after trauma. None of the teeth with a radiographically open apex at the time of lateral luxation showed complications. External root resorption was only seen in one tooth. Conclusions: Laterally luxated permanent teeth with incomplete root formation have a good prognosis, with all teeth surviving in this study. The most frequent complication was pulp necrosis that was only seen in teeth with closed apices.  相似文献   
4.
5.
6.
The aim of the study was to evaluate the applicability to urine samples of the AmplifiedMycobacterium tuberculosis Direct Detection Test (AMTD), which is currently used to identify this organism in respiratory specimens within a few hours. The study was performed on 95 patients, comprising 35 subjects with a high index of suspicion for active tuberculosis of the urinary tract and 60 subjects with evidence of non-mycobacterial disease. One urine specimen from each subject was examined by microscopy, culture and AMTD. AMTD was positive in 38 specimens and negative in 57. Assuming culture as the reference standard, the sensitivity, specificity, positive predictive value and negative predictive value of AMTD were 100%, 91.93%, 86.84% and 100%, respectively. Reassessing the discrepancies between AMTD and culture by review of patients' charts, the sensitivity, specificity, positive predictive value and negative predictive value of AMTD were 100%, 93.44%, 89.47% and 100%. The results of the study as well as the characteristics of AMTD encourage its use for the rapid recognition of urinary tract tuberculosis, although its findings should be interpreted cautiously when the clinical picture is not consistent with an active tuberculosis.  相似文献   
7.
8.
9.
Acetabular fractures represent a complex variety that are classified in different types. Conventional radiology is often inadequate to demonstrate and classify the fractures. Computed tomography (CT) has already been shown to be superior in this field. A further advantage of CT is represented by the recent availability of three-dimensional (3D) images that are realized from axial CT scans by means of a new software. The Authors report the applications of this new software to the study of the normal acetabulum and in patients with fractures. 3D images allows an effective demonstration of the fracture, its irradiation and the dislocation of bone fragments. The information is contained in one or few images rather than many axial images. Therefore the role of 3D images may be considered complementary to axial CT scans.  相似文献   
10.
BACKGROUND: Development of an acclimation protocol for use when measuring resting energy expenditure (REE) would simplify and standardize data collection. The purpose of this study was to determine if our 2 metabolic carts could be used interchangeably and to determine if excluding the first 3 or 5 minutes of data collected as an acclimation period would significantly improve the coefficients of variation (CVs) for oxygen consumed (VO(2)) and carbon dioxide produced (VCO(2)) when performing REE assessments with our metabolic cart systems. METHODS: Thirteen healthy, nonsmoking adults ranging in age from 32 to 45 years, with activity levels ranging from sedentary to highly active, participated. Indirect calorimetry was performed twice in the morning after 30 minutes of supine resting. Subjects had fasted for 12 hours, and did not exercise within the last 24 hours. The system order for testing was randomized for the first measurement. When the first measurement was completed, subjects were crossed over for measurement using a second metabolic cart. RESULTS: The CVs for VO(2) and VCO(2) were significantly lower when excluding the first 3 (VO(2), p = .0005), (VCO(2), p = .0024) or 5 minutes (VO(2), p = .0001, VCO(2), p = .0021) of data compared with no exclusions. No significant differences in CVs between the 3- and 5-minute exclusions were found for VO(2) (p = .3224) or VCO(2) (p = .2255). CONCLUSIONS: Clearly, our machines cannot be used interchangeably within a study. An acclimation period improves CVs of VO(2) and VCO(2.) The similarities in CVs led us to adopt a 3-minute acclimation period for measuring REE.  相似文献   
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