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   2397篇
  免费   225篇
  国内免费   84篇
耳鼻咽喉   4篇
儿科学   18篇
妇产科学   16篇
基础医学   346篇
口腔科学   31篇
临床医学   162篇
内科学   214篇
皮肤病学   12篇
神经病学   289篇
特种医学   63篇
外科学   101篇
综合类   227篇
预防医学   337篇
眼科学   13篇
药学   509篇
中国医学   333篇
肿瘤学   31篇
  2024年   9篇
  2023年   77篇
  2022年   135篇
  2021年   157篇
  2020年   116篇
  2019年   122篇
  2018年   111篇
  2017年   113篇
  2016年   108篇
  2015年   110篇
  2014年   158篇
  2013年   191篇
  2012年   186篇
  2011年   162篇
  2010年   105篇
  2009年   133篇
  2008年   121篇
  2007年   119篇
  2006年   81篇
  2005年   70篇
  2004年   45篇
  2003年   55篇
  2002年   20篇
  2001年   20篇
  2000年   29篇
  1999年   16篇
  1998年   12篇
  1997年   5篇
  1996年   14篇
  1995年   8篇
  1994年   8篇
  1993年   10篇
  1992年   12篇
  1991年   5篇
  1990年   7篇
  1989年   6篇
  1988年   8篇
  1987年   4篇
  1986年   2篇
  1985年   8篇
  1984年   5篇
  1983年   2篇
  1982年   1篇
  1981年   9篇
  1980年   2篇
  1979年   3篇
  1978年   4篇
  1976年   2篇
排序方式: 共有2706条查询结果,搜索用时 15 毫秒
1.
PurposeAccording to the social determinants of health framework, income inequality is a potential risk factor for adverse mental health. However, few studies have explored the mechanisms suspected to mediate this relationship. The current study addresses this gap through a mediation analysis to determine if social support and community engagement act as mediators linking neighbourhood income inequality to maternal anxiety and depressive symptoms within a cohort of new mothers living in the City of Calgary, Canada.MethodsData collected at three years postpartum from mothers belonging to the All Our Families (AOF) cohort were used in the current study. Maternal data were collected between 2012 and 2015 and linked to neighbourhood socioeconomic data from the 2006 Canadian Census. Income inequality was measured using Gini coefficients derived from 2006 after-tax census data. Generalized structural equation models were used to quantify the associations between income inequality and mental health symptoms, and to assess the potential direct and indirect mediating effects of maternal social support and community engagement.ResultsIncome inequality was not significantly associated with higher depressive symptoms (β = 0.32, 95%CI = −0.067, 0.70), anxiety symptoms (β = 0.11, 95%CI = −0.39, 0.60), or lower social support. Income inequality was not associated with community engagement. For the depression models, higher social support was significantly associated with lower depressive symptoms (β = −0.13, 95%CI = −0.15, −0.097), while community engagement was not significantly associated with depressive symptoms (β = 0.059, 95%CI = −0.15, 0.27). Similarly, for the anxiety models, lower anxiety symptoms were significantly associated with higher levels of social support (β = −0.17, 95%CI = −0.20, −0.13) but not with higher levels of community engagement (β = 0.14, 95%CI = −0.14, 0.41).ConclusionThe current study did not find clear evidence for social support or community engagement mediating the relationship between neighbourhood income inequality and maternal mental health. Future investigations should employ a broader longitudinal approach to capture changes in income inequality, potential mediators, and mental health symptomatology over time.  相似文献   
2.
《Seminars in Arthroplasty》2015,26(2):108-111
Bone loss is commonly encountered during revision total knee arthroplasty (TKA). Small defects can be adequately managed with cement filling (with or without screws), modular prosthetic augments, and morselized allograft. For larger defects, cancellous impaction grafting and structural allografts have traditionally been utilized. More recently, highly porous tantalum cones and titanium sleeves have been designed to achieve axial and rotational stability in the metaphysis and subsequent biologic fixation. Sleeves are linked to one type of prosthesis, whereas cones are unlinked and can be used with any implant design. Multiple studies have demonstrated excellent survivorship and radiographic osseointegration at mid-term follow-up. This article provides a review of contemporary methods of bone loss management with a focus on highly porous metals and an emphasis on the authors’ preferred method for managing the severe bone loss in revision TKA.  相似文献   
3.
4.
5.
Background & Aims: Impaired message-structure mapping results in deficits in both sentence production and comprehension in aphasia. Structural priming has been shown to facilitate syntactic production for persons with aphasia (PWA). However, it remains unknown if structural priming is also effective in sentence comprehension. We examined if PWA show preserved and lasting structural priming effects during interpretation of syntactically ambiguous sentences and if the priming effects occur independently of or in conjunction with lexical (verb) information.

Methods & Procedures: Eighteen PWA and 20 healthy older adults (HOA) completed a written sentence-picture matching task involving the interpretation of prepositional phrases (PP; the chef is poking the solider with an umbrella) that were ambiguous between high (verb modifier) and low attachment (object noun modifier). Only one interpretation was possible for prime sentences, while both interpretations were possible for target sentences. In Experiment 1, the target was presented immediately after the prime (0-lag). In Experiment 2, two filler items intervened between the prime and the target (2-lag). Within each experiment, the verb was repeated for half of the prime-target pairs, while different verbs were used for the other half. Participants’ off-line picture matching choices and response times were measured.

Results: After reading a prime sentence with a particular interpretation, HOA and PWA tended to interpret an ambiguous PP in a target sentence in the same way and with faster response times. Importantly, both groups continued to show this priming effect over a lag (Experiment 2), although the effect was not as reliable in response times. However, neither group showed lexical (verb-specific) boost on priming, deviating from robust lexical boost seen in the young adults of prior studies.

Conclusions: PWA demonstrate abstract (lexically-independent) structural priming in the absence of a lexically-specific boost. Abstract priming is preserved in aphasia, effectively facilitating not only immediate but also longer-lasting structure-message mapping during sentence comprehension.  相似文献   

6.
通过对某一工程的设计分析,表明了概念设计在结构设计中的重要性。  相似文献   
7.
We analyze whether the political system and its stability are related to cross-country differences in health. We apply factor analysis on various national health indicators for a large sample of countries over the period 2000–2005 and use the outcomes of the factor analysis to construct two new health measures, i.e., the health of individuals and the quality of the health care sector. Using a cross-country structural equation model with various economic and demographic control variables, we examine the relationship between the type of regime and political stability on the one hand and health on the other. The political variables and the control variables are measured as averages over the period 1980–1999. Our results suggest that democracy has a positive relationship with the health of individuals, while regime instability has a negative relationship with the health of individuals. Government instability is negatively related to individual health via its link with the quality of the health care sector, while democracy is positively related with individual health through its link with income. Our main findings are confirmed by the results of a panel model and various sensitivity tests.  相似文献   
8.
目的 分析山医群体中国地鼠E家系的遗传纯度。方法 应用经过筛选的 3 1条随机引物对中国地鼠E家系 12只个体基因组DNA进行RAPD扩增 ,计算近交个体间的相似系数。结果 所有样品的相似系数0 943 1到 0 9978之间变动 ,平均相似系数为 0 9749,聚类分析得到了这些个体的同源树资料。结论 山医群体E家系有较高的遗传纯度  相似文献   
9.
目的应用结构方程分析研究应激相关因素对护士生活质量的影响机制。方法通过随机抽样,采用生活质量综合评定问卷、压力反应问卷、生活事件量表、特质应对方式问卷、领悟社会支持量表、艾森克人格问卷对405名护士进行调查,并应用结构方程分析方法对其作用机制进行探索。结果在5个理论可行的竞争模型中获取了最佳模型(CMINDF2.344;GFI0.928;AGFI0.891;CFI0.945;RMSEA0.060),即应激相关5因素(压力反应、生活事件、社会支持、应对方式和个性特征)中除应对方式外均能直接影响生活质量,而应对方式则以其他应激相关因素为中介对生活质量产生间接影响,这5个因素均可互为中介对护士生活质量产生间接作用。结论结构方程分析方法证实应激对护士生活质量的影响是一个交叉作用系统,在干预应激对护士生活质量的影响时应综合运用直接和间接方法。  相似文献   
10.
OBJECTIVE: This study proposes a method for self-report health questionnaires to adjust test-retest reliability for changes during the test-retest interval based on an external measure, and to distinguish such changes from random response errors. METHODS: In our application, eighty participants completed the Symptoms of Illness Checklist (SIC) on two occasions, two weeks apart, immediately before interviews given on each occasion by one of two physicians in a crossover design. The physician interview scores served as external measures, and structural equation modeling was used to estimate the parameters of a model that corrected for the occasion-specific effect of participants' responses using information from the interviews. RESULTS: Correcting for changes in symptoms during the test-retest interval increased SIC test-retest reliability from .744 to .804 and significantly improved model fit (chi2(diff)(1) = 30.78, p < .001). CONCLUSIONS: The results suggest methods that can improve the evaluation of self-report health questionnaire test-retest reliability by identifying changes using an external measure, and distinguishing these from random response errors; these increased the estimated SIC test-retest reliability and indicated that the SIC was indeed able to measure changes over the studied time interval. This method can be applied across a broad range of questionnaires.  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