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   2516篇
  免费   132篇
  国内免费   22篇
耳鼻咽喉   25篇
儿科学   51篇
妇产科学   61篇
基础医学   206篇
口腔科学   123篇
临床医学   189篇
内科学   454篇
皮肤病学   79篇
神经病学   127篇
特种医学   115篇
外科学   493篇
综合类   45篇
一般理论   4篇
预防医学   284篇
眼科学   76篇
药学   175篇
中国医学   13篇
肿瘤学   150篇
  2024年   4篇
  2023年   30篇
  2022年   56篇
  2021年   114篇
  2020年   88篇
  2019年   114篇
  2018年   118篇
  2017年   80篇
  2016年   84篇
  2015年   108篇
  2014年   115篇
  2013年   166篇
  2012年   198篇
  2011年   202篇
  2010年   139篇
  2009年   88篇
  2008年   158篇
  2007年   154篇
  2006年   148篇
  2005年   122篇
  2004年   108篇
  2003年   74篇
  2002年   64篇
  2001年   17篇
  2000年   19篇
  1999年   25篇
  1998年   23篇
  1997年   8篇
  1996年   4篇
  1995年   5篇
  1994年   2篇
  1993年   1篇
  1992年   3篇
  1991年   6篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1984年   2篇
  1983年   1篇
  1981年   2篇
  1980年   3篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   2篇
  1974年   1篇
  1960年   1篇
排序方式: 共有2670条查询结果,搜索用时 318 毫秒
61.
62.
Background. This study reports on a new method for golf performance enhancement employing personalized real-life neurofeedback during golf putting.

Method. Participants (n = 6) received an assessment and three real-life neurofeedback training sessions. In the assessment, a personal event-locked electroencephalographic (EEG) profile at FPz was determined for successful versus unsuccessful putts. Target frequency bands and amplitudes marking optimal prefrontal brain state were derived from the profile by two raters. The training sessions consisted of four series of 80 putts in an ABAB design. The feedback in the second and fourth series was administered in the form of a continuous NoGo tone, whereas in the first and third series no feedback was provided. This tone was terminated only when the participants EEG met the assessment-defined criteria. In the feedback series, participants were instructed to perform the putt only after the NoGo tone had ceased.

Results. From the personalized event-locked EEG profiles, individual training protocols were established. The interrater reliability was 91%. The overall percentage of successful putts was significantly larger in the second and fourth series (feedback) of training compared to the first and third series (no feedback). Furthermore, most participants improved their performance with feedback on their personalized EEG profile, with 25% on average.

Conclusions. This study demonstrates that the “zone” or the optimal mental state for golf putting shows clear recognizable personalized patterns. The learning effects suggest that this real-life approach to neurofeedback improves learning speed, probably by tapping into learning associated with contextual conditioning rather than operant conditioning, indicating perspectives for clinical applications.  相似文献   
63.
Ortho mineral trioxide aggregate (MTA) is a mineral aggregate newly developed for perforation repair, root end filling and pulp capping. The aim of this study was to investigate the levels of cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni) and zinc (Zn) in Ortho MTA and ProRoot MTA. A total of 0.2 g of each MTA was digested using a mixture of hydrochloric and nitric acids and filtered. Six heavy metals in the resulting filtrates were analyzed by inductively coupled plasma–optical emission spectrometry (n = 5). The results were statistically analyzed using the Mann–Whitney U‐test. The concentrations of Cd, Cu, Fe, Mn, Ni and Zn in Ortho MTA were 0.10, 7.73, 49.51, 2.58, 0.82 and 10.09 p.p.m., respectively. The concentrations of Cd, Cu, Fe, Mn, Ni and Zn in ProRoot MTA were 0.16, 9.38, 1438.11, 74.51, 18.98 and 4.05 p.p.m., respectively. In conclusion, Ortho MTA had lower levels of Cd, Cu, Fe, Mn and Ni than ProRoot MTA.  相似文献   
64.
65.
66.
Being responsible for providing care for HIV/AIDS in a society, physicians should be knowledgeable and have favourable attitudes. We designed a cross-sectional study to assess knowledge and attitudes towards HIV/AIDS of private practicing physicians in Mashhad, Iran. A total of 346 general practitioners and specialists completed anonymous self-administered questionnaires with response rate of 91.1%. For knowledge questions, the mean proportion of correct responses was 53.5% (±13.2). Misconceptions about HIV transmission were the main areas of insufficient knowledge. Surprisingly only 20% knew how to manage a patient who had experienced sexual contact with an HIV-positive partner. While 84% disagreed that 'HIV-infected individuals deserved to catch infection' owing to high-risk behaviours, 38% sympathized less with people who were infected via extramarital sex. It seems that knowledge and attitudes towards HIV/AIDS among the studied physicians is not favourable and is an area that requires attention to enable effective management of the disease in Iran.  相似文献   
67.
68.
69.
Infectious disease surveillance for mass gatherings (MGs) can be directed locally and globally; however, epidemic intelligence from these two levels is not well integrated. Modelling activities related to MGs have historically focused on crowd behaviours around MG focal points and their relation to the safety of attendees. The integration of developments in internet-based global infectious disease surveillance, transportation modelling of populations travelling to and from MGs, mobile phone technology for surveillance during MGs, metapopulation epidemic modelling, and crowd behaviour modelling is important for progress in MG health. Integration of surveillance across geographic frontiers and modelling across scientific specialties could produce the first real-time risk monitoring and assessment platform that could strengthen awareness of global infectious disease threats before, during, and immediately after MGs. An integrated platform of this kind could help identify infectious disease threats of international concern at the earliest stages possible; provide insights into which diseases are most likely to spread into the MG; help with anticipatory surveillance at the MG; enable mathematical modelling to predict the spread of infectious diseases to and from MGs; simulate the effect of public health interventions aimed at different local and global levels; serve as a foundation for scientific research and innovation in MG health; and strengthen engagement between the scientific community and stakeholders at local, national, and global levels.  相似文献   
70.
Novel and effective reduced graphene oxide–nickel (Ni) doped manganese oxide (RGO/Ni-MnO2) adsorbents were fabricated via a hydrothermal approach. The reduction of graphite to graphene oxide (GO), formation of α-MnO2, and decoration of Ni-MnO2 onto the surface of reduced graphene oxide (RGO) were independently carried out by a hydrothermal technique. The physical and morphological properties of the as-synthesized adsorbents were analyzed. Batch adsorption experiments were performed to identify the lithium uptake capacities of adsorbents. The optimized parameters for Li+ adsorption investigated were pH = 12, dose loading = 0.1 g, Li+ initial concentration = 50 mg L−1, in 10 h at 25 °C. It is noticeable that the highest adsorption of Li+ at optimized parameters are in the following order: RGO/Ni3-MnO2 (63 mg g−1) > RGO/Ni2-MnO2 (56 mg g−1) > RGO/Ni1-MnO2 (52 mg g−1). A Kinetic study revealed that the experimental data were best designated pseudo-second order for each adsorbent. Li+ desorption experiments were performed using HCl as an extracting agent. Furthermore, all adsorbents exhibit efficient regeneration ability and to some extent satisfying selectivity for Li+ recovery. Briefly, it can be concluded that among the fabricated adsorbents, the RGO/Ni3-MnO2 exhibited the greatest potential for Li+ uptake from aqueous solutions as compared to others.

Novel and effective reduced graphene oxide–nickel (Ni) doped manganese oxide (RGO/Ni-MnO2) adsorbents were fabricated via a hydrothermal approach for lithium adsorption and recovery from aqueous media.  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