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   2622篇
  免费   245篇
  国内免费   29篇
耳鼻咽喉   22篇
儿科学   84篇
妇产科学   85篇
基础医学   352篇
口腔科学   26篇
临床医学   340篇
内科学   510篇
皮肤病学   103篇
神经病学   214篇
特种医学   98篇
外科学   258篇
综合类   82篇
预防医学   330篇
眼科学   33篇
药学   151篇
中国医学   1篇
肿瘤学   207篇
  2023年   22篇
  2022年   40篇
  2021年   73篇
  2020年   56篇
  2019年   100篇
  2018年   81篇
  2017年   60篇
  2016年   73篇
  2015年   83篇
  2014年   123篇
  2013年   122篇
  2012年   181篇
  2011年   196篇
  2010年   91篇
  2009年   80篇
  2008年   137篇
  2007年   126篇
  2006年   123篇
  2005年   106篇
  2004年   111篇
  2003年   80篇
  2002年   58篇
  2001年   50篇
  2000年   55篇
  1999年   35篇
  1998年   34篇
  1997年   34篇
  1996年   27篇
  1995年   21篇
  1994年   30篇
  1993年   19篇
  1992年   29篇
  1991年   29篇
  1990年   20篇
  1989年   34篇
  1988年   30篇
  1987年   34篇
  1986年   29篇
  1985年   22篇
  1984年   16篇
  1983年   11篇
  1982年   10篇
  1981年   16篇
  1980年   15篇
  1979年   20篇
  1978年   12篇
  1977年   11篇
  1976年   9篇
  1975年   11篇
  1966年   12篇
排序方式: 共有2896条查询结果,搜索用时 15 毫秒
61.
Carers of people with eating disorders are uncertain about how best to help and express the need for information. Fifty per cent of carers (usually parents) exhibit clinically significant anxiety and/or depression. This may result from a difficulty coping with the manifestations of anorexia nervosa (AN) in the sufferer. In turn, eating disorder symptoms can be maintained by family reactions to the illness. Thus, carer's own symptoms, plus their uncertainty about how to help, impinge upon the AN sufferer, exacerbating their symptoms and behaviours. In this paper, we describe an intervention which uses cognitive behavioural therapy principles to alleviate carer's depression and anxiety and motivational interviewing to target behaviours that maintain eating disorder symptoms, for example high expressed emotion and poor communication. This is given in the form of an educational workshop for two families. Copyright © 2011 John Wiley & Sons, Ltd and Eating Disorders Association.  相似文献   
62.
63.
64.
Donor organ shortages have prompted the development of alternative implantable human liver tissues for patients suffering from end-stage liver failure. Purified silk proteins provide desirable features for generating implantable tissues, including sustainable sourcing from insects/arachnids, biocompatibility, tunable mechanical properties and degradation rates, and low immunogenicity upon implantation. While different cell types were previously cultured for weeks within silk-based scaffolds, it remains unclear whether such scaffolds can be used to culture primary human hepatocytes (PHH) isolated from livers. Therefore, here we assessed the compatibility of PHH culture within porous silk scaffolds that enable diffusion of oxygen/nutrients through the pores. We found that incorporation of type I collagen during the fabrication and/or autoclaving of porous silk scaffolds, as opposed to simple adsorption of collagen onto pre-fabricated silk scaffolds, was necessary to enable robust PHH attachment/function. Scaffolds with small pores (73 ± 25 μm) promoted larger PHH spheroids and consequently higher PHH functions than large pores (235 ± 84 μm) for at least 1 month in culture. Further incorporation of supportive fibroblasts into scaffolds enhanced PHH functions up to 5-fold relative to scaffolds with PHHs alone and 2D co-cultures on plastic. Lastly, encapsulating PHHs within protein hydrogels while housed in the silk scaffold led to higher functions than protein hydrogel-only or silk-only controls. In conclusion, porous silk scaffolds containing extracellular matrix proteins can be used for the culture of PHHs ± supportive non-parenchymal cells, which can be further built on in the future to create optimized silk-based liver tissue surrogates for cell-based therapy.

Porous silk scaffolds hybridized with extracellular matrix proteins are useful for culture of primary human hepatocytes ± supportive non-parenchymal cells.  相似文献   
65.
66.
Sarcoidosis is a granulomatous disease of unknown etiology, characterized by a Th-1 immunophenotype. Although humoral immune responses by sarcoidosis subjects to mycobacterial proteins have been detected, mycobacterial antigens capable of inducing cellular immune responses in sarcoidosis subjects have not been reported. We used the enzyme-linked immunospot assay to assess for recognition of the Mycobacterium tuberculosis mycolyl transferase, Antigen 85A, by peripheral blood mononuclear cells from 25 sarcoidosis subjects, 22 PPD− (purified protein derivative) healthy volunteers, and 16 PPD+ healthy subjects. Reactivity to Ag85A whole protein was observed in 15 of 25 sarcoidosis subjects compared to 2 of 22 PPD− subjects (p=0.0006, Fisher’s exact test) and to 14 of 16 PPD+ subjects (p=0.084, Fisher’s exact test). Monoclonal antibody against HLA-DR inhibited recognition. In addition to immune recognition of Ag85A whole protein, peptide-mapping studies identified four immunogenic Ag85A peptides, which induced Th-1 immune responses in individual sarcoidosis subjects, suggesting that multiple epitopes from a mycobacterial protein may have a role in sarcoidosis immunopathogenesis.  相似文献   
67.
Topical DNA vaccination (DermaVir) facilitates antigen presentation to naive T cells. DermaVir immunization in mice, using HIV-1 Env and Gag, elicited cellular immune responses. Boosting with HIV-1 gp120 Env and p41 Gag augmented Th1 cytokine levels. Intramuscular DNA administration was less efficient in priming antigen-specific cytokine production and memory T cells. In rhesus macaques, DermaVir immunization induced Gag- and Env-specific Th1 and Th2 cytokines and generation of memory T cells. Boosting of DermaVir-primed serum antibody levels was noted following gp140(SHIV89.6P)/p27(SIV) immunization. Rectal challenge with pathogenic R5-tropic SHIV162P3 resulted in control of plasma viremia (4/5 animals) that was reflected in jejunum, colon and mesenteric lymph nodes. An inverse correlation was found between Gag- and Env-specific central memory T cell responses on the day of challenge and plasma viremia at set point. Overall, the topical DermaVir/protein vaccination yields central memory T cell responses and facilitates control of pathogenic SHIV infection.  相似文献   
68.

Objective

To develop a branding strategy for a campaign to improve the quality of foods children bring from home to school, using a combined healthy eating and eco-friendly approach and for a control campaign focusing solely on nutrition.

Methods

Formative research was conducted with third- and fourth-grade students in lower- and middle-income schools in Greater Boston and their parents. Phase I included concept development focus groups. Phase II included concept testing focus groups. A thematic analysis approach was used to identify key themes.

Results

In phase I, the combined nutrition and eco-friendly messages resonated; child preference emerged as a key factor affecting food from home. In phase II, key themes included fun with food and an element of mystery. Themes were translated into a concept featuring food face characters.

Conclusions and Implications

Iterative formative research provided information necessary to create a brand that appealed to a specified target audience.  相似文献   
69.

Background

Trauma exposure has been linked to risky sexual behavior (RSB), but few studies have examined the impact of distinct trauma types on RSB in one model or how the association with trauma and RSB may differ across race.

Purpose

The objective of the current study was to examine the contribution of trauma exposure types to RSB—substance-related RSB and partner-related RSB identified through factor analysis—in young Black and White adult women.

Methods

We investigated the associations of multiple trauma types and RSB factor scores in participants from a general population sample of young adult female twins (n = 2,948). We examined the independent relationship between specific traumas and RSB, adjusting for substance use, psychopathology, and familial covariates. All pertinent constructs were coded positive only if they occurred before sexual debut.

Results

In Black women, sexual abuse was significantly associated with substance-related and partner-related RSB, but retained significance only for partner-related RSB in a fully adjusted model. For White women, sexual abuse and physical abuse were associated with both RSB factors in the base and fully adjusted models. Witnessing injury or death was only associated with RSBs in base models. For both groups, initiating alcohol (for Black women), alcohol, or cannabis (for White women) before sexual debut (i.e., early exposure) was associated with the greatest increased odds of RSB.

Conclusions

Data highlight the contribution of prior sexual abuse to RSBs for both White and Black women, and of prior physical abuse to RSBs for White women. Findings have implications for intervention after physical and sexual abuse exposure to prevent RSB, and thus, potentially reduce sexually transmitted infection/human immunodeficiency virus infection and unintended pregnancy in young women.  相似文献   
70.
The presence of depression and anxiety in Parkinson's disease   总被引:1,自引:0,他引:1  
  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