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   2375947篇
  免费   194752篇
  国内免费   4215篇
耳鼻咽喉   34274篇
儿科学   72805篇
妇产科学   62977篇
基础医学   335026篇
口腔科学   67529篇
临床医学   215637篇
内科学   468745篇
皮肤病学   47942篇
神经病学   200822篇
特种医学   95981篇
外国民族医学   886篇
外科学   360476篇
综合类   56234篇
现状与发展   1篇
一般理论   979篇
预防医学   190748篇
眼科学   55465篇
药学   177575篇
  4篇
中国医学   4365篇
肿瘤学   126443篇
  2018年   24217篇
  2016年   20589篇
  2015年   23306篇
  2014年   33560篇
  2013年   50872篇
  2012年   68785篇
  2011年   72333篇
  2010年   42512篇
  2009年   40902篇
  2008年   68811篇
  2007年   73162篇
  2006年   74049篇
  2005年   72075篇
  2004年   69374篇
  2003年   67066篇
  2002年   66309篇
  2001年   112476篇
  2000年   116551篇
  1999年   98352篇
  1998年   27870篇
  1997年   25530篇
  1996年   25459篇
  1995年   24616篇
  1994年   23172篇
  1993年   21564篇
  1992年   79396篇
  1991年   76402篇
  1990年   73596篇
  1989年   70851篇
  1988年   65852篇
  1987年   64808篇
  1986年   61341篇
  1985年   58407篇
  1984年   44227篇
  1983年   37660篇
  1982年   22888篇
  1981年   20337篇
  1980年   19039篇
  1979年   41307篇
  1978年   28993篇
  1977年   24348篇
  1976年   22840篇
  1975年   23970篇
  1974年   29642篇
  1973年   28045篇
  1972年   26231篇
  1971年   24151篇
  1970年   22753篇
  1969年   21088篇
  1968年   19135篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
51.
52.
Obtaining accurate assessment data from adolescents in treatment aids clinical decision making and facilitates more accurate outcome evaluations. However, findings could be biased due to underreported substance use and mental health symptoms. This article compares self-reports of youth in non-White matched client–assessor dyads and those in nonmatched dyads. There were no differences on self-reported substance use, but matched youth reported significantly fewer attention deficit/hyperactivity disorder symptoms versus the comparison group. One possible reason for these findings is the effect of in-group stereotype threat. Future studies should examine the potential effect that in-group stereotyping and perceived racism have on the therapeutic relationship.  相似文献   
53.
54.
55.
This study explored the relationship between active mediation, exposure to Daniel Tiger’s Neighborhood, and key indicators of preschoolers’ social and emotional development. One hundred and twenty-seven children aged 2–6 either watched or did not watch 10 episodes of Daniel Tiger’s Neighborhood over a two-week period. Results revealed that preschoolers who watched the program exhibited higher levels of empathy, self-efficacy, and emotion recognition when their regular TV-watching experiences are frequently accompanied by active mediation. This was especially true for younger preschoolers and preschoolers from low-income families. Implications for policy-makers, parents, producers of prosocial programming, and educators are discussed.  相似文献   
56.
57.
On 8 April 2014, a US jury ordered Takeda and Eli Lilly to pay $9 bn in punitive damages after finding that they had concealed the cancer risks associated with pioglitazone. By contrast, on 28 August 2014, the long‐awaited outcome of the 10‐year Kaiser Permanente Northern California study was announced. That study was specifically designed to investigate whether patients exposed to pioglitazone were at an increased risk of bladder cancer and found no association; thus, at last, the controversial issue has been resolved. A review, in retrospect, of the story of the proposed link between pioglitazone and bladder cancer reveals flaws at every stage. In 2012, a BMJ editorial, in keeping with some other contemporary reports, stated ‘it can confidently be assumed that pioglitazone increases the risk of bladder cancer’. Examination of the information which led to such a statement shows that: 1) the pre‐clinical findings of bladder cancer in male rats is not indicative of human risk; 2) there is no association between bladder cancer and pioglitazone in randomized controlled trials, once cases that could not plausibly be related to treatment are removed; and 3) the observational studies that have suggested a link have over‐extrapolated from the data: pioglitazone‐treated patients had more risk factors for bladder cancer than those not treated with pioglitazone. Meanwhile careful study of randomized controlled trials shows evidence of cardiovascular benefit from pioglitazone in Type 2 diabetes, a condition which results, more than anything, in premature cardiovascular death and morbidity.  相似文献   
58.
59.
60.

Background

Obesity is a risk factor for acetabular component malposition when total hip arthroplasty is performed with manual techniques. The utility of imageless navigation in obese patients remains unknown. This study compared the accuracy and precision of imageless navigation for component orientation between obese and nonobese patients.

Methods

A total of 459 total hip arthroplasties performed for osteoarthritis using imageless navigation were reviewed from a single surgeon’s institutional review board–approved database. Einzel-Bild-Roentgen Analyse determined component orientation on 6-week postoperative anteroposterior radiographs. Mean orientation error (accuracy) and precision were compared between obese (body mass index ≥ 30 kg/m2) and nonobese patients. Regression analysis evaluated the influence of obesity on component position.

Results

The difference in mean inclination and anteversion between obese and nonobese groups was 1.1° (43.0° ± 3.5°; range, 35.8°-57.8° vs 41.9° ± 4.4°; range, 33.0°-57.1° and 24.9° ± 6.3°; range, 14.2°-44.3° vs 23.8° ± 6.6°; range, 7.0°-38.6°, respectively). Inclination precision was better for nonobese patients. No difference in inclination accuracy or anteversion accuracy or precision was detected between groups. And 83% of components were placed within the target range. There was no relationship between obesity (dichotomized) and component placement outside the target ranges for inclination, anteversion, or both. As a continuous variable, increased body mass index correlated with higher odds of inclination outside the target zone (odds ratio, 1.06; P = .001).

Conclusion

Using imageless navigation, inclination orientation was less precise for obese patients, but the observed difference is likely not clinically relevant. Accurate superficial registration of landmarks in obese patients is achievable, and the use of imageless navigation similarly improves acetabular component positioning in obese and nonobese patients.

Level of Evidence

Therapeutic Level IV.  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