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   2597篇
  免费   183篇
  国内免费   3篇
耳鼻咽喉   16篇
儿科学   131篇
妇产科学   70篇
基础医学   289篇
口腔科学   44篇
临床医学   232篇
内科学   618篇
皮肤病学   141篇
神经病学   256篇
特种医学   191篇
外科学   274篇
综合类   24篇
一般理论   1篇
预防医学   127篇
眼科学   69篇
药学   137篇
中国医学   1篇
肿瘤学   162篇
  2023年   12篇
  2022年   26篇
  2021年   64篇
  2020年   39篇
  2019年   80篇
  2018年   82篇
  2017年   47篇
  2016年   58篇
  2015年   51篇
  2014年   73篇
  2013年   83篇
  2012年   103篇
  2011年   118篇
  2010年   89篇
  2009年   78篇
  2008年   124篇
  2007年   96篇
  2006年   119篇
  2005年   101篇
  2004年   85篇
  2003年   81篇
  2002年   80篇
  2001年   59篇
  2000年   97篇
  1999年   57篇
  1998年   56篇
  1997年   68篇
  1996年   64篇
  1995年   54篇
  1994年   28篇
  1993年   35篇
  1992年   40篇
  1991年   43篇
  1990年   27篇
  1989年   46篇
  1988年   45篇
  1987年   40篇
  1986年   48篇
  1985年   32篇
  1984年   24篇
  1983年   15篇
  1982年   14篇
  1981年   22篇
  1980年   18篇
  1979年   14篇
  1978年   16篇
  1977年   14篇
  1976年   14篇
  1975年   22篇
  1973年   17篇
排序方式: 共有2783条查询结果,搜索用时 15 毫秒
41.
The cellular prion protein, encoded by Prnp gene, is involved in neuroprotection, neuroplasticity and neurodevelopment. The variant allele Valine at codon 129 of the Prnp was associated with decreased brain volume in healthy volunteers and schizophrenic patients. We investigate the association between the cerebellum volume and the presence of variant allele Valine at codon 129 of the Prnp gene in patients with mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS). The Prnp coding sequence was determined in 41 refractory MTLE-HS patients. The cerebellum volume corrected by the intracranial volume of patients with the normal Prnp genotypes was compared with that of patients presenting the variant alleles at codon 129. Twenty patients showed the Met129Met genotype, 16 showed Met129Val, and 5 had Val129Val. There were no association among clinical, demographic, electrophysiological, antiepileptic drugs used, and the presence of the Prnp variant alleles. The presence of Prnp variant allele at codon 129 was not associated with the analyzed cerebellum volume. Prnp variant alleles at codon 129 are not associated with cerebellum volume in patients with refractory MTLE-HS.  相似文献   
42.
Journal of Natural Medicines - Neurological disorders are a public health problem worldwide for which there is currently no direct treatment of the cause of the disorder. The goal of this study was...  相似文献   
43.
Clinical Oral Investigations - This study evaluated the effectiveness of class II restorations, in permanent teeth, through the ART technique in comparison to composite resin. Participants (154),...  相似文献   
44.

Objectives

To analyze the factorial structure of a new instrument to assess the quality of the family context (Etxadi-Gangoiti Scale) in a sample from the Gipuzkoa cohort of the Environment and Childhood (Infancia y Medio Ambiente [INMA]) study.

Methods

Families in a sample of 433 two-year-old children were assessed in a home visit with subsequent analysis of the factorial structure and psychometric properties of the data.

Results

An exploratory factorial analysis (principal axis factoring and varimax rotation) and a confirmatory factorial analysis were carried out; partial confirmation of the original factorial structure of the instrument was obtained, which revealed the following factorial structures. Subscale (1): promotion of cognitive and linguistic development, social skills, psychomotor skills, and pretend play and imitation; subscale (2): promotion of independence and self-esteem, provision of optimal frustration, social and emotional quality of the relationship, and absence of physical punishment; subscale (3): paternal involvement, low exposure to family conflict, low frequency of family conflict, relationship with the extended family, social support, diversity of experiences, low frequency of stressful events, and low parental perception of stress.

Discussion

The structure of the original instrument structure was partially confirmed, which was attributed to the characteristics of the sample. We stress the importance of the variability obtained in the evaluation of the families, as well as of adequate indicators of reliability in such evaluation. The new instrument could be used in public health to identify deficient family contexts and to design preventive interventions focused on parenting skills.  相似文献   
45.
Systemic non‐biologic agents have long been in clinical use in medicine – often with considerable efficacy, albeit with some adverse effects – as with all medications. With the advent of biologic agents, all of which currently are restricted to systemic use, there is a growing need to ensure which agents have the better therapeutic ratio. The non‐biologic agents (NBAs) include a range of agents, most especially the corticosteroids (corticosteroids). This study reviews the corticosteroids in systemic use in management of orofacial mucocutaneous diseases; subsequent studies discuss corticosteroid‐sparing agents used in the management of orofacial diseases, such as calcineurin inhibitors used to produce immunosuppression; purine synthetase inhibitors; and cytotoxic and other immunomodulatory agents.  相似文献   
46.
47.
A series of chiral mesogenic side chain polymers containing a carbazole unit have been synthesized and investigated with regard to their liquid crystal (1c) phase behaviour. The carbazole units are linked either via the 2-position with a 1-oxycarbonyl-4-alkoxylphenyl moiety (end-on) or via the 9-position with an alkyl chain (side-on) to polymethylsiloxane. Only end-on polymers with long spacers or a ratio bigger one of spacer length and the free lateral alkyl chain length exhibit stable or metastable smectic phases. The side-on polymers are only isotropic or crystalline.  相似文献   
48.
Graphene-related materials (GRMs) such as graphene quantum dots (GQDs), graphene oxide (GO), reduced graphene oxide (rGO), graphene nanoribbons (GNRs), and so forth have recently emerged as photovoltaic (PV) materials due to their nanodimensional structure and outstanding properties such as high electrical and thermal conductivity, large specific surface, and unique combination of mechanical strength and flexibility. They can be a crucial part of transparent electrodes, hole/electron transport materials, and active layers in organic solar cells (OSCs). Besides their role in charge extraction and transport, GRMs act as device protectors against environmental degradation through their compact bidimensional structure and offer good durability. This review briefly presents the synthesis methods of GRMs and describes the current progress in GRM-based OSCs. PV parameters (short circuit current, open circuit voltage, power conversion efficiency, and fill factor) are summarized and comparatively discussed for the different structures. The efficiency recently surpassed 15% for an OSC incorporating polymer-modified graphene as a transparent electrode. The long-term stability of OSCs incorporating GRMs is also discussed. Finally, conclusions and the outlook for future investigation into GRM-based devices for PVs are presented.  相似文献   
49.
50.
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