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   5074篇
  免费   290篇
  国内免费   12篇
耳鼻咽喉   15篇
儿科学   119篇
妇产科学   115篇
基础医学   916篇
口腔科学   36篇
临床医学   605篇
内科学   1060篇
皮肤病学   124篇
神经病学   505篇
特种医学   93篇
外科学   511篇
综合类   13篇
一般理论   1篇
预防医学   357篇
眼科学   66篇
药学   309篇
  1篇
中国医学   7篇
肿瘤学   523篇
  2024年   10篇
  2023年   35篇
  2022年   43篇
  2021年   99篇
  2020年   84篇
  2019年   96篇
  2018年   108篇
  2017年   73篇
  2016年   105篇
  2015年   134篇
  2014年   177篇
  2013年   239篇
  2012年   391篇
  2011年   406篇
  2010年   229篇
  2009年   224篇
  2008年   350篇
  2007年   352篇
  2006年   356篇
  2005年   380篇
  2004年   323篇
  2003年   365篇
  2002年   323篇
  2001年   47篇
  2000年   22篇
  1999年   41篇
  1998年   65篇
  1997年   51篇
  1996年   31篇
  1995年   47篇
  1994年   36篇
  1993年   19篇
  1992年   14篇
  1991年   18篇
  1990年   16篇
  1989年   12篇
  1988年   7篇
  1987年   7篇
  1986年   8篇
  1985年   4篇
  1984年   7篇
  1983年   2篇
  1982年   4篇
  1981年   3篇
  1980年   3篇
  1979年   5篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
  1970年   1篇
排序方式: 共有5376条查询结果,搜索用时 31 毫秒
91.
92.
OBJECTIVE: To assess the effects of acetic acid iontophoresis on the treatment of calcifying tendinitis of the shoulder. DESIGN: Double-blind randomized controlled trial. SETTING: Ambulatory academic hospital in Quebec, Canada. PARTICIPANTS: Thirty-six subjects with a calcifying tendinitis of the shoulder. INTERVENTIONS: Subjects were randomized into 1 of 2 groups: physiotherapy during 6 weeks (10 sessions) plus acetic acid iontophoresis for the treatment group (n=18) and sham acetic acid iontophoresis for the control group (n=18). MAIN OUTCOME MEASURES: The Shoulder Pain and Disability Index (SPADI), shoulder range of motion (ROM); and radiologic evaluation of shoulder calcifications. RESULTS: Nine patients dropped out, leaving 27 assessable subjects for analysis. Interim analysis showed that, in both groups, treatment led to improvement, as measured by the SPADI score (P=.004), ROM of the shoulder for abduction (P<.001), internal rotation (P=.001), external rotation (P<.001), and the mean number of calcifications per subject (P=.010). Although no formal significant intervention effects (P=.13) were found for the primary endpoint (SPADI), exploratory analyses suggest a greater improvement in the treatment group (P=.001) than in the control group (P=.33). CONCLUSIONS: Despite a trend toward greater improvement in the SPADI score in the treatment group, the use of acetic acid iontophoresis and physiotherapy for the treatment of calcifying tendinitis of the shoulder did not result in better clinical and radiologic effects than those observed in subjects treated by physiotherapyalone.  相似文献   
93.
OBJECTIVE: To determine whether treatment with combined pentoxifylline (PTX) and tocopherol (Vit.E) can improve uterine parameters in hormonal replacement therapy (HRT)-resistant women with premature ovarian failure (POF), for whom the outcome of assisted reproductive technology is usually negative. We previously reported that uterine radiation-induced fibrosis is reversible by combined PTX-Vit.E treatment. DESIGN: Case report. SETTING: Volunteer participants in an oocyte donation (OD) program in a French public hospital. PATIENT(S): Three women with POF (ages 36 +/- 2 years) using HRT exhibited uterine hormonoresistance, although they had high E(2) plasma levels. Their mean endometrial thickness was 4.9 mm, and they had an echogenic endometrium and thin uterine crosses. INTERVENTION(S): Between May 1998 and April 1999, treatment consisted of 800 mg of PTX combined with 1,000 IU of Vit.E daily for at least 9 months. MAIN OUTCOME MEASURE(S): Endometrial thickness, echogenicity, and pulsatility index of the uterine arteries, assessed by ultrasound and Doppler before and after treatment, and embryo implantation by IVF-OD. RESULT(S): PTX-Vit.E treatment was well tolerated and induced improvements, as mean edematous endometrial thickness increased to 7.4 mm, with nice uterine crosses. Three frozen-thawed ETs resulted in two viable pregnancies. CONCLUSION(S): In women with POF and uterine resistance to HRT, combined PTX-Vit.E reduces fibroatrophic uterine lesions and improves the uterine response to HRT, thus allowing embryo implantation and ongoing pregnancy.  相似文献   
94.
BACKGROUND: Fulminant hepatic failure (FHF) is associated with high mortality; few patients survive without liver transplantation. It is important to have a sensitive, specific early predictor of outcome to distinguish potential survivors (S) from nonsurvivors (NS). OBJECTIVE: Because we had previously shown that glycine conjugation of para-aminobenzoic acid (PABA) quantitatively reflects liver function in children with chronic liver disease, in this pilot study we wanted to determine whether the measurement of the glycine conjugates of PABA could distinguish S from NS in FHF in comparison with standard prognostic indices. METHODS: Twenty-four patients were studied: acute severe hepatitis (n = 7), subfulminant hepatic failure (n = 7), and FHF (n = 10). Assessment of King's College criteria, measurement of factor V and VII levels, PABA testing, and transjugular liver biopsies were performed in almost all patients within 48 hours of admission. Serum PABA and its glycine conjugates (para-aminohippurate (PAHA) and para-acetamidohippurate (PAAHA)) were measured thirty minutes after oral administration by high-pressure liquid chromatography. Poor prognostic categories as previously established in the literature were defined as factor V < 0.20U/ml, factor VII < 0.08 U/ml, % necrosis >70%, hippurate ratio = 0%, and PAHA = 0M. RESULTS: The measurement of PAHA was the best predictor of a poor outcome in patients with acute liver failure with a sensitivity of 92%, and negative predictive value (NPV) of 92% compared with a sensitivity of 54% and a NPV of 63% with King's College criteria. CONCLUSION: Measurement of serum PAHA is the best early prognostic marker of death in children who suffer from FHF.  相似文献   
95.
A critical examination of the recent literature on anxiety and depression in juvenile diabetes is presented. The objectives of this review are: (1) to determine the general association of psychological factors, especially anxiety and depression, with diabetes, (2) to examine the specific association of anxiety and depression with metabolic control, and (3) to propose methodological changes that are needed to advance future research in this field. The major conclusions of this review support the notion of a general association of psychological disorders with juvenile diabetes. However, while anxiety and depression appear to play an important and complex role in determining adaptation to the disease, their relationship to metabolic control does not yet appear clear. Additional prospective and controlled studies as well as multivariate models of chronic disease are now necessary to more fully understand the etiology and impact of these disorders in the adolescent population.  相似文献   
96.
The dopaminergic system is one of the most important targets for pharmacological treatment of schizophrenia. Despite substantial work on mechanisms of action, it is not clear which dopaminergic pathways mediate the therapeutic effects of antipsychotic drugs. It has been shown that chronic clozapine, an atypical antipsychotic, decreases dopamine levels in the mesocorticolimbic system but not in the nigrostriatal system. Because tyrosine hydroxylase is the rate-limiting enzyme in the biosynthesis of dopamine, we studied the effect of chronic clozapine in both dopaminergic systems. We demonstrated a decrease of tyrosine hydroxylase mRNA not only in the ventral tegmental area but also in the substantia nigra, the cell body areas of the mesocorticolimbic and the nigrostriatal systems, respectively. The reduced tyrosine hydroxylase mRNA level in these areas is accompanied by an ample reduction in the tyrosine hydroxylase protein level in their corresponding axonal terminal fields, the nucleus accumbens and the striatum. There was thus discordance between the clozapine-induced decrease of tyrosine hydroxylase mRNA and protein and the absence of an effect on dopamine levels in the nigrostriatal system. It has been suggested that reduced levels of dopamine in the mesocorticolimbic system are required for the antipsychotic effect of the drug. Therefore, the modulation of tyrosine hydroxylase gene expression by clozapine in the mesocorticolimbic system might be necessary for its antipsychotic effect; this effect might be of relevance when considering new atypical agents.  相似文献   
97.
KIS is the only known protein kinase that possesses an RNA recognition motif. This original structure indicates a role for KIS in the maturation of RNAs possibly by phosphorylating and regulating the activities of RNA associated factors. Another function of KIS has recently been unravelled--it negatively regulates the cdk inhibitor p27Kip1 and thus promotes cell cycle progression through G1. In order to explore the functional expression of this kinase, we quantified its mRNA in a wide range of rat and human tissues, during development and in tumors. In both species, the highest level of KIS gene expression was in adult neural tissues. Interestingly, within the adult rat brain, KIS mRNA is enriched in several areas including the substantia nigra compacta and nuclei of the brain stem. Furthermore, KIS gene expression increases dramatically during brain development. Altogether our results point to a ubiquitous function for KIS together with a particular implication during neural differentiation or in the function of mature neural cells. No dysregulation of KIS gene expression was detected in human tumors from breast, bladder, prostate, liver and kidney origins. On the other hand, the KIS gene was overexpressed in NF1-associated plexiform neurofibromas and malignant peripheral nerve sheath tumors (MPNSTs) as compared to dermal neurofibroma which suggests a possible implication of KIS in the genesis of NF1-associated tumors.  相似文献   
98.
Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by a loss of atonia and an increase in phasic muscle activity during REM sleep, leading to complex nocturnal motor behaviors. Brainstem structures responsible for the pathogenesis of RBD are also implicated in cortical activation. To verify the hypothesis that electroencephalogram (EEG) activation will be impaired in RBD, we performed quantitative analyses of waking and REM sleep EEG in 15 idiopathic RBD patients and 15 age- and gender-matched healthy subjects. During wakefulness, RBD patients showed a considerably higher theta power in frontal, temporal, and occipital regions with a lower beta power in the occipital region. The dominant occipital frequency was significantly lower in RBD. During REM sleep, beta power in the occipital region was lower in RBD. This study shows for the first time an impaired cortical activation during both wakefulness and REM sleep in idiopathic RBD, despite an absence of changes on sleep architecture compared with controls. EEG slowing in these patients may represent an early sign of central nervous system dysfunction, perhaps paralleled by subclinical cognitive deficits. The topographical distribution of EEG slowing and possible pathophysiological mechanisms are discussed in light of the known association between RBD and neurodegenerative disorders.  相似文献   
99.
Homeless drug users and prostitutes constitute a population at risk for contracting and propagating AIDS. This study aims at understanding the paradox related to drug injection and prostitution among 21 homeless from Montreal. These behaviors are studied following the picoeconomic paradox of an apprehended desire. The results show that these homeless see drug injection as a self-reward motivated by imaginary emotional object, in spite of the known and dreaded consequences. Prostitution is described as a self-investment accessory to drug injection. This study concludes with reflections on AIDS prevention programs in relation with the needs of the homeless.  相似文献   
100.
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