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   26527篇
  免费   454篇
  国内免费   20篇
教育   19011篇
科学研究   2266篇
各国文化   263篇
体育   2307篇
综合类   20篇
文化理论   261篇
信息传播   2873篇
  2022年   246篇
  2021年   370篇
  2020年   529篇
  2019年   844篇
  2018年   1115篇
  2017年   1086篇
  2016年   948篇
  2015年   593篇
  2014年   819篇
  2013年   5202篇
  2012年   824篇
  2011年   771篇
  2010年   569篇
  2009年   564篇
  2008年   607篇
  2007年   549篇
  2006年   474篇
  2005年   462篇
  2004年   410篇
  2003年   392篇
  2002年   382篇
  2001年   499篇
  2000年   412篇
  1999年   372篇
  1998年   225篇
  1997年   225篇
  1996年   266篇
  1995年   248篇
  1994年   193篇
  1993年   214篇
  1992年   338篇
  1991年   316篇
  1990年   320篇
  1989年   307篇
  1988年   262篇
  1987年   311篇
  1986年   275篇
  1985年   309篇
  1984年   252篇
  1983年   214篇
  1982年   196篇
  1981年   169篇
  1980年   161篇
  1979年   264篇
  1978年   190篇
  1977年   175篇
  1976年   157篇
  1975年   143篇
  1974年   149篇
  1971年   140篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
221.
The present study examines how language use (e.g., personalized vs. depersonalized language) and modality (e.g., tweets vs. Facebook status updates) influence source credibility interdependently. A total of 257 participants read personalized or depersonalized health messages embedded in mock-up tweets or Facebook status updates. The results show that users perceive depersonalized tweets as more credible than depersonalized status updates posted on Facebook. On the other hand, personalized status updates on Facebook generate higher credibility judgments than personalized tweets. The findings are discussed in light of the MAIN model as well as the preconceived user expectations and communication norms of social media.  相似文献   
222.
This study investigated the degree to which religious pluralistic language varies as a function of the intergroup salience of a context and religious orientation. Based on a 2 (Religious Salience of Context) × 3 (Religious Salience of Topic) experimental design, participants (N = 239) were instructed to compose an e-mail to an interactional partner based on the randomly assigned condition. Messages were coded for religious pluralistic language, and participants completed measures of religious orientation and evaluations of the conversational partner. Modest effects were found for both intergroup salience of the context and topic as well as religious orientation.  相似文献   
223.
A bibliography of periodicals focused on planning within the urban studies field is presented. The bibliography contains scholarly, trade, and popular titles. Each entry contains identical categories of information (where each category is applicable), including an annotation. The bibliography is meant to aid in collection development in this subject area.  相似文献   
224.
225.
226.
A substantial amount of evidence suggests that collegiate and elite athletes involved in weight-sensitive sports are at greater risk of developing eating disorders (EDs) than the general population. With the limited effectiveness of treatment for EDs, prevention of EDs has been broadly considered in the literature. The present paper reviewed the existing literature on ED prevention programmes for athletes in order to determine the current status of prevention programmes and recommend future directions. The available literature suggests that selective, primary interventions with multiple targets and an interactive multimodal approach appear most effective. Current challenges in the field, including lack of longitudinal research, hesitation by the sport community to be involved in ED research and poor cross-field communication and collaboration, are also explored. The lack of dissemination of evidence-based prevention programmes and the simultaneous promotion of prevention programmes that have not yet been empirically examined are also discussed. Based on these observations future directions are recommended.  相似文献   
227.

Introduction

Screening programs for colorectal cancer (CRC) are mainly based on a first-line fecal immunochemical test for hemoglobin (FIT). Fecal M2-type pyruvate kinase (M2-PK) has been evaluated in clinical settings showing promising results for early CRC detection. However, the impact of fecal M2-PK assessment on the performance of first-round CRC screening programs is not known. We investigated whether fecal M2-PK alone or in combination with FIT may improve CRC screening efficacy in the general population.

Materials and methods

A total of 1027 asymptomatic subjects (median age 66 [59-74] years; females 504 [49.1%]), identified through the general practitioners’ rosters, were invited for the collection of 2 fecal samples for FIT and M2-PK evaluation. Participants with at least positive one fecal test were referred for colonoscopy. Quality indicators for screening performance were calculated and analyzed using Fisher’s exact test.

Results

Overall, 572 subjects underwent both FIT and M2-PK assessment (participation rate 55.7%): 93 participants showed positive results for at least one test (positivity rate 16.3%). Only 10 patients were positive for both tests. Attendance rate to colonoscopy was 86.0% and a total of 65 adenomas and 7 cancers were detected. Combined use of FIT and fecal M2-PK permitted the identification of 18 more neoplasm (25%) without improving colonoscopy workload, as deduced by the comparable number needed to scope (P = 0.402).

Conclusion

The addition of M2-PK testing to FIT offers the potential to detect additional neoplasms that either do not bleed or only bleed intermittently without reducing participation rate and without increasing endoscopy workload.Key words: biomarker, colorectal cancer, occult blood, M2-type pyruvate kinase, screening  相似文献   
228.
229.
The prevalence of ischaemia-related symptoms is remarkably high among elite indoor volleyball players. Since the exposure to sport-specific demands may be higher in beach volleyball compared to indoor volleyball, the aim of this study was to assess the prevalence of ischaemia-related symptoms and associated risk factors among world-class beach volleyball players. Therefore, a questionnaire survey was performed among beach volleyball players active during the 2013 Grand Slam Beach Volleyball in the Netherlands. In total, 60 of the 128 beach volleyball players (47%) participated: 26 males and 34 females from 17 countries. The self-reported prevalence of cold or blue or pale digits in the dominant hand during or immediately after practice or competition was 38% (n = 23). Two risk factors were independently associated with symptoms of blue or pale digits: more than 14 years playing volleyball (odds ratio (OR) 4.42, 90% confidence interval (90% CI) 1.30–15.07) and sex (female) (OR 4.62, 90% CI 1.15–18.57). In conclusion, the prevalence of symptoms associated with digital ischaemia is high among international world-class beach volleyball players. Female sex and the length of the volleyball career were independently associated with an increased risk of ischaemia-related symptoms. The high prevalence of these seemingly innocuous symptoms and possible associated risk factors warrant regular monitoring since early detection can potentially prevent thromboembolic complications and irreversible tissue damage.  相似文献   
230.
Research examining our ability to avoid obstacles in our path has stressed the importance of visual input. The aim of this study was to determine if athletes playing varsity-level field sports, who rely on visual input to guide motor behaviour, are more able to guide their foot over obstacles compared to recreational individuals. While wearing kinematic markers, eight varsity athletes and eight age-matched controls (aged 18–25) walked along a walkway and stepped over stationary obstacles (180° motion arc). Visual input was manipulated using PLATO visual goggles three or two steps pre-obstacle crossing and compared to trials where vision was given throughout. A main effect between groups for peak trail toe elevation was shown with greater values generated by the controls for all crossing conditions during full vision trials only. This may be interpreted as athletes not perceiving this obstacle as an increased threat to their postural stability. Collectively, findings suggest the athletic group is able to transfer their abilities to non-specific conditions during full vision trials; however, varsity-level athletes were equally reliant on visual cues for these visually guided stepping tasks as their performance was similar to the controls when vision is removed.  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