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   10905篇
  免费   691篇
  国内免费   65篇
耳鼻咽喉   62篇
儿科学   247篇
妇产科学   281篇
基础医学   1541篇
口腔科学   396篇
临床医学   996篇
内科学   2233篇
皮肤病学   195篇
神经病学   1334篇
特种医学   321篇
外科学   1255篇
综合类   25篇
现状与发展   1篇
一般理论   8篇
预防医学   982篇
眼科学   121篇
药学   714篇
中国医学   49篇
肿瘤学   900篇
  2024年   17篇
  2023年   121篇
  2022年   248篇
  2021年   424篇
  2020年   257篇
  2019年   393篇
  2018年   429篇
  2017年   340篇
  2016年   394篇
  2015年   372篇
  2014年   465篇
  2013年   605篇
  2012年   874篇
  2011年   851篇
  2010年   455篇
  2009年   431篇
  2008年   679篇
  2007年   643篇
  2006年   634篇
  2005年   577篇
  2004年   541篇
  2003年   476篇
  2002年   386篇
  2001年   116篇
  2000年   86篇
  1999年   111篇
  1998年   59篇
  1997年   70篇
  1996年   39篇
  1995年   34篇
  1994年   31篇
  1993年   24篇
  1992年   56篇
  1991年   66篇
  1990年   35篇
  1989年   42篇
  1988年   36篇
  1987年   35篇
  1986年   27篇
  1985年   27篇
  1984年   25篇
  1983年   8篇
  1982年   15篇
  1981年   9篇
  1980年   8篇
  1979年   11篇
  1977年   11篇
  1974年   13篇
  1973年   10篇
  1971年   8篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
Epithelioid hemangioendothelioma (EHE) is a rare, vascular sarcoma. Visceral forms arise in the liver/ lungs. We review the clinical and molecular phenotype of pediatric visceral EHE based on the case of a 9‐year‐old male child with EHE of the liver/lungs. His tumor expressed the EHE‐specific fusion oncogene WWTR1‐CAMTA1. Molecular characterization revealed a low somatic mutation rate and activated interferon signaling, angiogenesis regulation, and blood vessel remodeling. After polychemotherapy and resection of lung tumors, residual disease remained stable on oral lenalidomide. Literature review identified another 24 children with EHE of the liver/lungs. Most presented with multifocal, systemic disease. Only those who underwent complete resection achieved complete remission. Four children experienced rapid progression and died. In six children, disease remained stable for years without therapy. Two patients died from progressive EHE 21 and 24 years after first diagnosis. Natural evolution of pediatric visceral EHE is variable, and long‐term prognosis remains unclear.  相似文献   
982.
Numerical understanding is important for everyday life. For children with developmental dyscalculia (DD), numbers and magnitudes present profound problems which are thought to be based upon neuronal impairments of key regions for numerical understanding. The aim of the present study was to investigate possible differences in white matter fibre integrity between children with DD and controls using diffusion tensor imaging. White matter integrity and behavioural measures were evaluated in 15 children with developmental dyscalculia aged around 10 years and 15 matched controls. The main finding, obtained by a whole brain group comparison, revealed reduced fractional anisotropy in the superior longitudinal fasciculus in children with developmental dyscalculia. In addition, a region of interest analysis exhibited prominent deficits in fibres of the superior longitudinal fasciculus adjacent to the intraparietal sulcus, which is thought to be the core region for number processing. To conclude, our results outline deficient fibre projection between parietal, temporal and frontal regions in children with developmental dyscalculia, and therefore raise the question of whether dyscalculia can be seen as a dysconnection syndrome. Since the superior longitudinal fasciculus is involved in the integration and control of distributed brain processes, the present results highlight the importance of considering broader domain-general mechanisms in the diagnosis and therapy of dyscalculia.  相似文献   
983.
984.
985.
MZB1 (pERp1) is a B-cell-specific and endoplasmic reticulum (ER)-localized protein implicated in antibody secretion and integrin-mediated cell adhesion. Here, we examine the role of MZB1 in vivo by conditional gene inactivation in the mouse germline and at different stages of B lymphopoiesis. Deletion of MZB1 impairs humoral immune responses and antibody secretion in plasma cells that naturally undergo ER stress. In addition, we found that experimental induction of ER stress by tunicamycin injections in mice results in a block of pro-B-cell to pre-B-cell differentiation specifically in Mzb1/ mice. A similar developmental block was observed in Mzb1fl/flmb1Cre mice, whereby a Cre recombinase-induced genotoxic stress unmasks a role for MZB1 in the surface expression of immunoglobulin µ heavy chains (µHCs). MZB1 associates directly with the substrate-specific chaperone GRP94 (also called HSP90B1 or gp96) in an ATP-sensitive manner and is required for the interaction of GRP94 with µHCs upon ER stress. Thus, MZB1 seems to act as a substrate-specific cochaperone of GRP94 that enables proper biosynthesis of µHCs under conditions of ER stress.  相似文献   
986.
Deficiencies in the inhibitory functioning of gamma-aminobutyric acid (GABA) have been implicated in the pathophysiology of depressive disorders. Reproductive life cycle events, including menstruation, pregnancy, and menopause, are consistently associated with increased psychopathology, in particular mood disorders. Given that GABA-inhibitory activity may be modulated directly or indirectly by estrogen, progesterone, and their metabolites receptors, it has been hypothesized that GABA deficits may be evident during these reproductive periods. We aimed to compare GABA function among women during these “high-risk” reproductive periods to GABA function among women at other time periods. We conducted a systematic review of studies comparing women during reproductive life stages associated with depressive disorder risk (luteal phase of the menstrual cycle, perinatal period, and menopausal transition) to women at other time periods. The study outcome was GABA function. The review included 11 studies, 9 focused on the menstrual cycle, and 2 focused on the perinatal period. GABA-inhibitory function fluctuated across the menstrual cycle, with differing patterns in women with and without depressive disorders. GABA-inhibitory function was reduced in pregnancy and early postpartum compared to the nonpregnant state. Key limitations were the absence of studies evaluating the menopausal transition, and the heterogeneity of GABA outcome measures. GABA-inhibitory function fluctuates across the menstrual cycle and is reduced perinatally. This has potential implications for a role of GABAergically mediated interventions in the prevention and treatment of menstrual cycle-related and perinatal depressive disorders.  相似文献   
987.
988.
Objective: Several studies have examined the characteristics of anti‐smoking advertisements that are associated with quitting behaviour. Some studies use researchers or graduate students to code advertisement characteristics, while others recruit smokers or members of the general public. The aim of this study was to assist future campaign development by assessing whether anti‐smoking advertisement characteristics are coded differently by smokers and ‘experts’ (individuals with knowledge of health promotion, public health or advertising). Methods: A total of 49 smokers and 42 experts coded anti‐smoking advertisements according to four key characteristics (emotional/cognitive approach, negative/positive tone, message frame, and main message) and the use of eight executional techniques. Chi‐squared tests were used to measure differences in coding outcomes between smokers and experts. Results: There were significant differences between smokers and experts in the coding of all key characteristics and four of the eight executional techniques. Compared with smokers, experts were more likely to perceive advertisements as negative in tone and as inducing fear. Conclusions: Smokers and experts perceived the characteristics of anti‐smoking advertisements differently. Implications for public health: Differences between smokers and experts may need to be taken into account where studies use either of these groups to code advertisements for campaign development or evaluation purposes.  相似文献   
989.
The development of general approaches for the isolation of efficient antivirals and the identification and validation of targets for drug screening are becoming increasingly important, due to the emergence of previously unrecognized viral diseases. The genetic suppressor element (GSE) technology is an approach based on the functional expression selection of efficient genetic inhibitors from random fragment libraries derived from a gene or genome of interest. We have applied this technology to isolate potent genetic inhibitors against HIV-1. Two strategies were used to select for GSEs that interfere with latent virus induction and productive HIV-1 infection based on the expression of intracellular and surface antigens. The selected GSEs clustered in seven narrowly defined regions of the HIV-1 genome and were found to be functionally active. These elements are potential candidates for the gene therapy of AIDS. The developed approaches can be applied to other viral pathogens, as well as for the identification of cellular genes supporting the HIV-1 life cycle.  相似文献   
990.
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