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   7865篇
  免费   590篇
  国内免费   36篇
耳鼻咽喉   76篇
儿科学   238篇
妇产科学   235篇
基础医学   1181篇
口腔科学   140篇
临床医学   850篇
内科学   1603篇
皮肤病学   206篇
神经病学   761篇
特种医学   165篇
外科学   692篇
综合类   73篇
一般理论   9篇
预防医学   922篇
眼科学   119篇
药学   642篇
中国医学   19篇
肿瘤学   560篇
  2024年   11篇
  2023年   81篇
  2022年   124篇
  2021年   310篇
  2020年   190篇
  2019年   262篇
  2018年   290篇
  2017年   186篇
  2016年   241篇
  2015年   265篇
  2014年   332篇
  2013年   417篇
  2012年   679篇
  2011年   684篇
  2010年   396篇
  2009年   308篇
  2008年   529篇
  2007年   509篇
  2006年   498篇
  2005年   444篇
  2004年   371篇
  2003年   354篇
  2002年   319篇
  2001年   33篇
  2000年   32篇
  1999年   36篇
  1998年   61篇
  1997年   51篇
  1996年   33篇
  1995年   36篇
  1994年   31篇
  1993年   19篇
  1992年   16篇
  1991年   24篇
  1990年   13篇
  1989年   8篇
  1988年   13篇
  1987年   16篇
  1986年   16篇
  1985年   29篇
  1984年   16篇
  1983年   14篇
  1982年   17篇
  1981年   20篇
  1980年   21篇
  1979年   12篇
  1977年   8篇
  1974年   9篇
  1973年   12篇
  1928年   13篇
排序方式: 共有8491条查询结果,搜索用时 15 毫秒
31.
The purpose of this study was to investigate the contribution of reversal theory constructs (i.e., metamotivational states) to understanding the outcome of tempting situations thatoccur in the first 6 weeks of smoking cessation. Cessation program participants (N = 68) were interviewed about tempting situations in which they either smoked or maintained abstinence. Both independent groups and repeated measures analyses indicated that metamotivational state (serious and goal-directed vs. playful and spontaneous) and cigarette availability significantly predicted outcome. Reversal theory constructs correctly predicted outcome of the tempting episode for 70% of the subjects, while cigarette availability was an accurate predictor for 74%. Metamotivational state and cigarette availability together predicted the outcome for 89% of the subjects. ©1995 John Wiley & Sons, Inc.  相似文献   
32.
33.
34.
Describes the development and evaluation of a pilot 12-session, school-based preventive intervention designed to enhance resilience among inner-city children who have experienced major life stress. Thirty-six 4th–6th grade children participated in the intervention in groups of 5–8 co-led by school personnel. The curriculum focussed on understanding feelings in oneself and others, perspective-taking, social problem-solving, dealing with solvable and unsolvable problems, and building self-efficacy and esteem. Pre-post evaluation showed significant improvement among participants on teacher-rated indices of learning problems and task orientation and on child ratings of perceived self-efficacy, realistic control attributions and anxiety. Program limitations and factors that restrict generalization are considered and new directions for program development and research are proposed.  相似文献   
35.
36.
Untested assumptions concerning ambulatory treatment have shaped mental health policies for decades. Three opinions prevail: (1) all use is alike; (2) any use leads to high use; and (3) all high use is discretionary and therefore excessive. These assumptions were tested, using data from a nationwide survey of ambulatory utilizers in Israel, a country that has universal coverage. The findings, based on detailed clinical and treatment records, challenge all three assumptions. Moreover, they document a diversity of clinical needs while also verifying substantial variations in the type, frequency, and duration of treatment provided to meet those needs. In brief, Israeli data do not confirm continuing concerns by policy makers about uncontrollable use of services with expanded mental health coverage. Special policy limitations on mental health treatment should be reconsidered in light of empirical evidence from a system without the restrictions that exist in the United States.  相似文献   
37.
Zusammenfassung Die Wirkung des ?thylazetatextraktes von Chrysanthemum morifolium auf P. falciparum wurde in vitro untersucht. W?hrend sich die Parasit?mie bei der Kontrollgruppe bis zu 10. 90 % entwickelte, wurde bei dem mit ?thylazetatextrakt in einer Konzentration von 100 μg/ml Medium am 5. Tag der Kultur eine signifikante Hemmwirkung auf die Parasiten beobachtet. Die Parasit?mie blieb bei 1. 00 %.
Diese Arbeit wurde durch die Stiftung von “National Nature Science Foundation of China” finanziert (No. 39260066)  相似文献   
38.
Hereditary nephrotic syndrome is a heterogeneous disease, characterizedby heavy proteinuria and renal failure. Mutations of NPHS1 orNPHS2, the genes encoding for nephrin and podocin, lead to earlyonset of heavy proteinuria, and rapid progression to end-stagerenal disease, suggesting that both proteins are essential forthe integrity of the glomerular filter. Podocin is a stomatinprotein family member with a predicted hairpin-like structurelocalizing to the insertion site of the slit diaphragm of podocytes,the visceral glomerular epithelial cells of the kidney. Herewe investigate the pathomechanisms of different disease-causingpodocin mutations. We show that wild-type podocin is targetedto the plasma membrane, and forms homo-oligomers involving thecarboxy and amino terminal cytoplasmic domains. The associationof podocin with specialized lipid raft microdomains of the plasmamembrane was a prerequisite for recruitment of nephrin intorafts. In contrast, disease-causing mutations of podocin (R138Qand R138X) failed to recruit nephrin into rafts either becausethese mutants were retained in the endoplasmic reticulum (R138Q),or because they failed to associate with rafts (R138X) despitetheir presence in the plasma membrane. None of the mutants didaugment nephrin signaling, suggesting that lipid raft targetingfacilitates nephrin signaling. Our findings demonstrate thatthe failure of mutant podocin to recruit nephrin into lipidrafts may be essential for the pathogenesis of NPHS2. * To whom correspondence should be addressed. Tel: +49 7612703559;Fax: +49 7612706362; Email: benzing{at}med1.ukl.uni-freiburg.de   相似文献   
39.
Clericuzio-type poikiloderma with neutropenia is a well-defined nosological entity, but despite a remarkable number of clinical reports, no long term follow-up data has been presented to date regarding patients with this rare condition.Here we describe the results of clinical follow-up of three siblings, one male (Patient 1) and two females (Patients 2 and 3), subsequent to their first clinical and then molecular diagnosis of Clericuzio-type poikiloderma with neutropenia syndrome due to mutation of USB1gene. Patient 1 always expressed the most severe phenotype, while patients 2 and 3 showed an intermediate and mild phenotype, respectively, as observed since their first clinical evaluation. None of the patients developed skin cancer and/or myelodysplastic disorders considering the peripheral haematological findings. Lens opacity, never reported before, was found in two of the three patients.The long term follow-up observations confirm the stability over time of the pronounced intra-familial heterogeneity of clinical manifestations observed prior to and upon molecular diagnosis. We conclude that prolonged follow-up is an adjunct tool to monitor intra-familial variability of PN clinical spectrum which may favour surveillance of more serious complications of the disease among siblings, when a patient-specific clinical expressivity is present.  相似文献   
40.
OBJECTIVES: To determine whether improvement in endothelial function of the brachial artery observed in women treated with hormone replacement therapy (HRT) may be explained by changes in lipid profile or blood pressure, information was used obtained in a single-centre, randomised, double blind, placebo-controlled trial. METHODS: Hundred-and-five healthy postmenopausal women, aged 50-65 years, were treated with 0.625 mg conjugated equine estrogens (CEE) combined with 2.5 mg medroxyprogesterone acetate (MPA) (CEE+MPA), 2.5 mg tibolone or placebo for 3 months. At baseline and after 3 months, endothelial function was assessed using flow-mediated dilatation (FMD) and nitro glycerine-mediated dilatation (NMD). Furthermore, lipids were measured. Multivariate linear regression analysis was applied to address the research question. RESULTS: Treatment with CEE+MPA resulted in an improvement in FMD of 2.0% (95% CI: -0.1; 4.1). CEE/MPA reduced total cholesterol with 13% (95% CI: -18%; -7%), LDL-cholesterol with 23% (95% CI: -30%; -15%) and lipoprotein(a) (Lp(a)) with 14% (95% CI: -26%; -2%). The magnitude of the relation of CEE/MPA with endothelial function was attenuated to from 2.0 to 1.6% when change in Lp(a) was taken into account. Adjustments for other lipids or blood pressure did not attenuate the association. CONCLUSIONS: The improvement in endothelial function in postmenopausal women treated with CEE+MPA appears to be partially mediated by change in Lp(a), and apparently not by changes in other lipids.  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