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   6235篇
  免费   347篇
  国内免费   106篇
耳鼻咽喉   14篇
儿科学   33篇
妇产科学   13篇
基础医学   463篇
口腔科学   25篇
临床医学   474篇
内科学   969篇
皮肤病学   21篇
神经病学   791篇
特种医学   102篇
外科学   105篇
综合类   469篇
预防医学   327篇
眼科学   28篇
药学   2669篇
  1篇
中国医学   93篇
肿瘤学   91篇
  2023年   33篇
  2022年   35篇
  2021年   103篇
  2020年   99篇
  2019年   127篇
  2018年   132篇
  2017年   171篇
  2016年   164篇
  2015年   156篇
  2014年   320篇
  2013年   865篇
  2012年   285篇
  2011年   328篇
  2010年   305篇
  2009年   308篇
  2008年   345篇
  2007年   308篇
  2006年   276篇
  2005年   239篇
  2004年   184篇
  2003年   216篇
  2002年   171篇
  2001年   142篇
  2000年   143篇
  1999年   117篇
  1998年   82篇
  1997年   82篇
  1996年   74篇
  1995年   77篇
  1994年   76篇
  1993年   67篇
  1992年   46篇
  1991年   31篇
  1990年   35篇
  1989年   31篇
  1988年   29篇
  1987年   57篇
  1986年   35篇
  1985年   68篇
  1984年   43篇
  1983年   26篇
  1982年   36篇
  1981年   32篇
  1980年   39篇
  1979年   36篇
  1978年   30篇
  1977年   25篇
  1976年   24篇
  1975年   10篇
  1974年   11篇
排序方式: 共有6688条查询结果,搜索用时 15 毫秒
1.
2.
3.
《Clinical lung cancer》2020,21(2):171-176
BackgroundPatients with lung cancer continue to smoke owing to complex factors. Failure to quit smoking (defined as nicotine dependence) is significantly associated with genetic status. This study aimed to investigate the relationship between polymorphisms in nicotine dependence genes and smoking status after the diagnosis of lung cancer.Patients and MethodsA total of 240 patients with lung cancer were included from July 2017 to March 2018. According to the actual smoking condition after lung cancer diagnosis, eligible patients were divided into 3 groups: the never-smoking group, the failure to quit smoking group, and the successful smoking cessation group. Fagerstrom Test for Nicotine Dependence scores were used to evaluate the smoking status of each group. Three nicotine-dependent genes with 6 loci were detected.ResultsAmong the 240 patients, 86 were never-smokers, 51 failed to quit smoking, and 104 successfully quit smoking. The initial age of smoking in the failure to quit smoking group was significantly younger than those in the successful smoking cessation group (P = .001). There was a significant difference in the GG and AG and AA genotype distributions of CHRNA3 (rs578776) among the 3 groups (P = .003). There was also a significant difference in the distribution of CHRNA4 (rs2229959) genotypes among the 3 groups (P = .003). However, there was no significant difference in the genotype distribution of CHRNA5 (rs588765) among the 3 groups (P = .277).ConclusionsGene polymorphisms of CHRNA3 (rs578776) and CHRNA4 (rs1044396 and rs2229959) were associated with the success of smoking cessation after the diagnosis of lung cancer, which should be considered in the management of smoking cessation after patients are diagnosed with lung cancer.  相似文献   
4.
The frequently applied narrow and non-standard transverse dose profiles of intensity modulated photon-beam radiotherapy, lacking lateral secondary electron equilibrium, require the use of high-resolution dosimetry detectors, and small air-filled detectors are recommended as the reference detectors for cross-calibration of the high-resolution detectors. The present study focuses on the dosimetric properties of a novel cylindrical ionization chamber, the PTW Semiflex 3D 31021. The chamber's effective point of measurement was found to lie at (0.41 ± 0.04) r downstream the tip of the inner surface of the spherical front wall in the axial orientation and (0.46 ± 0.04) r upstream the chamber axis in the radial orientation. Due to its symmetrical design, the sigma values of its lateral dose response functions for all chamber's orientations are the same (2.10 ± 0.05 mm). The polarity correction factors obtained in this work do not exceed 0.1% and the saturation correction factor was below 1% up to a dose-per-pulse value of 0.956 mGy. The radiation quality correction factor kQ of the chamber as a function of the tissue-phantom-ratio, TPR20,10, has been calculated by Monte Carlo simulation and has been determined experimentally at the German Metrology Institute (Physikalisch-Technische Bundesanstalt, PTB). The values of the non-reference condition correction factor kNR have been Monte-Carlo-calculated for use of the chamber at various depths and field sizes.  相似文献   
5.
6.
7.
8.
ObjectiveTo evaluate the impact of the Plan for the promotion of personal autonomy and prevention of disability in Andalusia (2016-2020) in 13 public administrations during the first year of its implementation; and to analyse the usability and feasibility of the impact assessment ladder used.MethodThe Plan addresses the promotion of personal autonomy and the prevention of disabilities and dependencies through a multisectoral approach. It is structured in strands or lines of work, objectives and actions that have been assessed through the Adoption Impact Ladder (AIL). The analysis of the face validity, feasibility and inter-rater reliability of the impact assessment ladder was carried out in 30 actions of the Plan that were rated by 20 experts from the 13 ministries and public agencies involved in the Plan, and an external rater.Results176 actions and programmes were launched in 2017. Of these, 67.2% were implemented during the first year. Only one of the 16 objectives had no action initiated during the first year. Moreover, 7 out of 15 objectives implemented were fully multisectoral involving more than three Regional Ministries. The face validity, feasibility and inter-rater reliability of the AIL were good (κ: 0.72).ConclusionsThis Plan has provided a novel framework to coordinate a broad range of proposed policies and actions within the public administration of Andalusia. For the first time, a multisectoral impact analysis has been conducted providing an effective guide for monitoring, planning and setting public priorities in health, social services, ageing and disabilities.  相似文献   
9.
10.
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