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   1773106篇
  免费   149723篇
  国内免费   29028篇
耳鼻咽喉   21146篇
儿科学   51328篇
妇产科学   45157篇
基础医学   240049篇
口腔科学   43680篇
临床医学   178256篇
内科学   332898篇
皮肤病学   37304篇
神经病学   134480篇
特种医学   67211篇
外国民族医学   688篇
外科学   242115篇
综合类   102104篇
现状与发展   89篇
一般理论   519篇
预防医学   137383篇
眼科学   41804篇
药学   138284篇
  433篇
中国医学   27568篇
肿瘤学   109361篇
  2022年   18391篇
  2021年   28877篇
  2020年   21121篇
  2019年   23169篇
  2018年   28483篇
  2017年   24163篇
  2016年   24811篇
  2015年   32558篇
  2014年   43144篇
  2013年   52198篇
  2012年   73202篇
  2011年   79291篇
  2010年   49346篇
  2009年   44262篇
  2008年   65306篇
  2007年   67497篇
  2006年   67158篇
  2005年   64739篇
  2004年   56197篇
  2003年   53724篇
  2002年   50024篇
  2001年   80662篇
  2000年   82009篇
  1999年   69230篇
  1998年   22123篇
  1997年   20380篇
  1996年   19432篇
  1995年   18427篇
  1994年   16450篇
  1993年   14537篇
  1992年   47972篇
  1991年   45391篇
  1990年   43086篇
  1989年   40939篇
  1988年   37315篇
  1987年   36366篇
  1986年   33690篇
  1985年   31855篇
  1984年   24152篇
  1983年   20268篇
  1982年   12331篇
  1979年   20818篇
  1978年   14624篇
  1977年   12121篇
  1976年   11388篇
  1975年   11643篇
  1974年   14019篇
  1973年   13561篇
  1972年   12656篇
  1971年   11482篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Children who expect they can bring about good outcomes and avoid bad outcomes tend to experience more personal successes. Little is known about factors that contribute to these ‘control expectancies’. The purpose of the present study was to determine whether children's internal control expectancies occur in the context of parents’ internal control expectancies, low family strain, and high family cohesiveness and whether these factors are more strongly related to daughters’ than sons’ control expectancies. A community sample of 85 children aged 9–11 years and their parents (85 mothers; 63 fathers) completed rating scales. Fathers’ more internal control expectancies and mothers’ reports of fewer family strains were associated with daughters’ but not sons’ greater internal control expectancies, and greater family cohesiveness was related to both daughters’ and sons’ internal control orientations. These findings suggest that family factors may contribute to children's, particularly daughters’, development of internal control expectancies.  相似文献   
102.
Objective: Polyunsaturated fatty acids n-3 (PUFA n-3) have shown effects in reducing tumor growth, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) abundantly present in fish oil (FO). When these fatty acids are provided in the diet, they alter the functions of the cells, particularly in tumor and immune cells. However, the effects of α-linolenic fatty acid (ALA), which is the precursor of EPA and DHA, are controversial. Thus, our objective was to test the effect of this parental fatty acid. Methods: Non-tumor-bearing and tumor-bearing Wistar rats (70 days) were supplemented with 1 g/kg body weight of FO or Oro Inca® (OI) oil (rich in ALA). Immune cells function, proliferation, cytokine production, and subpopulation profile were evaluated. Results: We have shown that innate immune cells enhanced phagocytosis capacity, and increased processing and elimination of antigens. Moreover, there was a decrease in production of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6)) by macrophages. Lymphocytes showed decreased proliferation capacity, increased cluster of differentiation 8 (CD8+) subpopulation, and increased TNF-α production. Conclusions: Oil rich in ALA caused similar immune modulation in cancer when compared with FO.  相似文献   
103.
Reactive lymphoid infiltrates of the skin composed predominantly of gamma‐delta (γδ) T cells are not well described in the literature. Herein we report a case of an otherwise healthy 4‐year‐old male who presented with a waxing and waning papular rash characterized by small, discrete crusted papules spread across his trunk, face and extremities. Clinical evaluation revealed no evidence of systemic disease. Microscopic examination revealed a dermal, perivascular infiltrate of highly atypical lymphocytes with a γδ T cell phenotype, worrisome for primary cutaneous γδ T cell lymphoma. The clinical course, however, was that of a reactive condition and prompted consideration of a diagnosis of pityriasis lichenoides et varioliformis acuta (PLEVA) and lymphomatoid papulosis (LyP). In many ways, this case defies current classification schemes and seems to expand the spectrum of reactive γδ T cell infiltrates of the skin.  相似文献   
104.
105.
106.
107.
陈海  杨黎  王晓华 《医学综述》2016,(4):778-781
目的研究葛根素联合复方樟柳碱注射液对眼底病患者的治疗效果及对血液流变学指标的影响。方法选择2013年4月至2014年4月在绵阳市第三人民医院眼科进行眼底病治疗的患者100例,并按入院顺序抽签随机分为观察组和对照组,各50例。对照组进行葛根素常规治疗(葛根素注射液0.4 g加入生理盐水250 m L中静脉滴注,每日1次,1个疗程14 d,1个疗程后停药3 d,再进行下一疗程),观察组在此基础上联合复方樟柳碱注射液进行治疗(采用复方樟柳碱2 m L在患者颞浅动脉旁行皮下注射,每日1次,1个疗程14 d,完成1个疗程后停药3 d,再换肾俞穴进行注射,1个疗程后停药3 d,再进行第一个疗程的用药)。3个疗程后,比较两组患者治疗前后血液流变学的变化、术后复发率和不良反应情况及患者的治疗效果。结果治疗后,观察组全血黏度为(4.82±0.41)m Pa·s明显低于对照组的(5.56±0.39)m Pa·s,红细胞聚集指数(3.80±0.41)明显低于对照组(4.77±0.55),纤维蛋白原(4.20±0.24)g/L明显低于对照组(5.25±0.43)g/L,差异均有统计学意义(t=9.247,9.998,15.077,P<0.01);观察组患者治疗后复发率为2.0%(1/50),不良反应的总发生率为4.0%(2/50),分别低于对照组14.0%(7/50)和18.0%(9/50)(P<0.01);观察组患者的总有效率为98.0%(49/50),显著高于对照组的82.0%(41/50)(P<0.05)。结论葛根素和复方樟柳碱注射液联合治疗眼底病患者,可改善患者血液流变学,并提高临床治疗效果。  相似文献   
108.
109.
DNA methylation at CpG dinucleotides is an important epigenetic regulator common to virtually all mammalian cell types, but recent evidence indicates that during early postnatal development neuronal genomes also accumulate uniquely high levels of two alternative forms of methylation, non-CpG methylation and hydroxymethylation. Here we discuss the distinct landscape of DNA methylation in neurons, how it is established, and how it might affect the binding and function of protein readers of DNA methylation. We review studies of one critical reader of DNA methylation in the brain, the Rett syndrome protein methyl CpG-binding protein 2 (MeCP2), and discuss how differential binding affinity of MeCP2 for non-CpG and hydroxymethylation may affect the function of this methyl-binding protein in the nervous system.  相似文献   
110.
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