Punctiform thoracic pain modified by respiration and digitalcompression is normally atypical pain due to angina and generallyrequires no further diagnostic investigation. In this article,we present the case of a young patient  相似文献   
10.
1 [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] 下一页 » 末  页»
  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   8161篇
  免费   494篇
  国内免费   61篇
耳鼻咽喉   81篇
儿科学   214篇
妇产科学   192篇
基础医学   844篇
口腔科学   281篇
临床医学   672篇
内科学   2225篇
皮肤病学   191篇
神经病学   657篇
特种医学   319篇
外科学   1392篇
综合类   22篇
预防医学   365篇
眼科学   170篇
药学   465篇
中国医学   14篇
肿瘤学   612篇
  2023年   65篇
  2022年   132篇
  2021年   287篇
  2020年   166篇
  2019年   205篇
  2018年   255篇
  2017年   197篇
  2016年   197篇
  2015年   258篇
  2014年   320篇
  2013年   392篇
  2012年   538篇
  2011年   565篇
  2010年   332篇
  2009年   287篇
  2008年   464篇
  2007年   515篇
  2006年   441篇
  2005年   439篇
  2004年   381篇
  2003年   302篇
  2002年   291篇
  2001年   154篇
  2000年   179篇
  1999年   145篇
  1998年   76篇
  1997年   62篇
  1996年   40篇
  1995年   36篇
  1994年   33篇
  1993年   27篇
  1992年   96篇
  1991年   102篇
  1990年   96篇
  1989年   72篇
  1988年   77篇
  1987年   75篇
  1986年   59篇
  1985年   53篇
  1984年   31篇
  1983年   32篇
  1982年   19篇
  1980年   16篇
  1979年   20篇
  1978年   13篇
  1977年   13篇
  1974年   18篇
  1973年   18篇
  1972年   14篇
  1970年   16篇
排序方式: 共有8716条查询结果,搜索用时 15 毫秒
1.
2.
3.
The aim of our study was to investigate the impact of the epsilon phenotype in brain glucose consumption in a population with Alzheimer’s disease. Statistical Parametric Mapping (SPM8) was used to investigate differences in brain glucose consumption (as detectable by means of 18F FDG-PET/CT) in the population examined. A total of 129 patients (72 females and 57 males) with a diagnosis of probable AD according to the NINCDS-ADRDA criteria underwent the PET/CT examination. The mean (SD) age of the patients was 70 (± 7) years; the mean Mini-Mental State Examination was 19(± 5.6). 59 expressed epsilon 4 phenotype (E4) and 70 expressed the epsilon 3 phenotype (E3). Cerebral spinal fluid amyloid, tau, and t-tau have been measured resulting equal to 367.4 (± 149.1), 584.7 (± 312.1), and 79.2(± 45.9) pg/ml, respectively. Patients with confirmed amyloid and Tau changes were classified as AD. Patients with amyloid changes but negative Tau, considered as high risk of AD, were classified as IAD. Age, sex, MMSE, scholarship, and CSF parameters were used as a covariate in the SPM analyses. We did not find significant differences in age, gender, and MMSE and CSF parameters among groups. In the analysis of the AD group as compared to AD-E3, AD-E4 subjects show a significant reduction of brain glucose consumption in inferior frontal gyrus bilaterally (BA 45, BA 47). In the analysis of the IAD group as compared to IAD-E3, IAD-E4 subjects show a significant reduction of brain glucose consumption in right in medial, middle, and superior frontal gyrus (BA10, BA11), and in left medial and middle frontal gyrus (BA10, BA11). The differences between IAD-E3 and AD-E3 and between IAD-E4 and AD-E4 (and vice versa analysis) resulted not significant. APO-e4 is related to a major involvement of the frontal cortex confirming its role of risk factor in AD, while APO-3 seems not related to a specific pattern, supporting the hypothesis of neutral/protective role in AD.  相似文献   
4.
This study evaluated the effect of new motions of the motor TriAuto ZX2 on the cyclic fatigue of endodontic instruments. Vortex Blue 35.06 instruments were divided into four groups (n = 10) and tested for fatigue in a curved artificial canal (90° and 2 mm radius) using the following motions: continuous rotation (CR), Optimum Torque Reverse (OTR) set at 180° and the Optimum Glide Path (OGP), which was tested at 90° and 240°. The time to fracture (TTF) and the lengths of the fractured fragments were recorded. The mean TTF was significantly different among the groups (anova , P < 0.05): OGP 90° (213.39 ± 27.45), OTR 180° (121.24 ± 17.03), OGP 240° (45.24 ± 5.61) and CR (8.43 ± 1.27). Weibull analysis confirmed the shortest life expectancy for CR and the longest survival for OGP at 90°. The resistance to fatigue was affected by motions and pre‐set angles. The proprietary movements that are currently available for endodontic instruments were classified according to their kinematics.  相似文献   
5.
We developed a self-administered questionnaire for screening the most common adult-onset dystonias. It was tested in 90 first-degree relatives of 22 adult-onset dystonia patients, yielding 79% sensitivity and 94% specificity. Simulation of a case-finding procedure based on serial application of the questionnaire and clinical examination of both subjects screening positive and subjects screening negative who had < 8 years of schooling increased sensitivity to 95% and specificity to 100%. This questionnaire may be an important screening resource for familial aggregation studies to be used in the context of a complex case-finding procedure.  相似文献   
6.
7.
8.
The efficiency of a new prothrombin-based activated protein C (APC) resistance test to detect factor V Leiden (FVL) was clinically evaluated in 150 Italian patients with deep venous thrombosis. Patient samples are diluted in factor-V-deficient plasma, an APC-containing reagent, and specific factor V activator; after incubation, clotting is initiated by addition of activated-factor-FV-dependent prothrombin activator. Two prothrombin time determinations were performed under identical assay conditions except that no APC was added to one. A ratio over 4.2 for normal individuals and under 2.0 for FVL patients is expected: between 1.3 and 1.9 for FVL heterozygotes, and between 1.0 and 1.1 for FVL homozygotes. Using a predefined cut-off ratio of 2.0, a specificity and a sensitivity of 1.00 for detection of FVL mutation were found. With a cut-off ratio of 1.1, a specificity of 0.98 and a sensitivity of 1.00 were found for discrimination between FVL heterozygous (n = 60) and homozygous (n = 6). No interferences by heparins, oral contraceptives, oral anticoagulant therapy, protein C, protein S, D-dimer, homocysteine, MTHFR mutations and antiphospholipid autoantibodies were detected. In our experience, this new prothrombin time-based APC resistance assay provides improved discrimination between normal individuals and FVL carriers compared with the classical methods. Moreover, this new assay allows good discrimination between homozygous and heterozygous FVL carriers. In the authors' experience this prothrombin time-based method was not influenced by many factors compared with the classical activated partial thromboplastin time-based method.  相似文献   
9.
   Case presentation
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