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   1912篇
  免费   215篇
  国内免费   5篇
耳鼻咽喉   11篇
儿科学   23篇
妇产科学   15篇
基础医学   313篇
口腔科学   19篇
临床医学   169篇
内科学   546篇
皮肤病学   23篇
神经病学   223篇
特种医学   36篇
外科学   336篇
综合类   12篇
现状与发展   1篇
预防医学   121篇
眼科学   30篇
药学   151篇
中国医学   2篇
肿瘤学   101篇
  2023年   13篇
  2022年   50篇
  2021年   60篇
  2020年   40篇
  2019年   49篇
  2018年   51篇
  2017年   33篇
  2016年   36篇
  2015年   51篇
  2014年   46篇
  2013年   93篇
  2012年   127篇
  2011年   132篇
  2010年   80篇
  2009年   72篇
  2008年   104篇
  2007年   106篇
  2006年   127篇
  2005年   118篇
  2004年   146篇
  2003年   103篇
  2002年   87篇
  2001年   29篇
  2000年   25篇
  1999年   28篇
  1998年   23篇
  1997年   22篇
  1996年   12篇
  1995年   13篇
  1994年   6篇
  1993年   7篇
  1992年   16篇
  1991年   10篇
  1990年   9篇
  1989年   13篇
  1988年   11篇
  1987年   14篇
  1986年   21篇
  1985年   10篇
  1984年   15篇
  1983年   8篇
  1982年   7篇
  1981年   9篇
  1980年   8篇
  1979年   8篇
  1978年   6篇
  1977年   9篇
  1976年   6篇
  1974年   11篇
  1969年   5篇
排序方式: 共有2132条查询结果,搜索用时 15 毫秒
11.
Paget's disease of bone is a localized disorder of bony resorption. The mechanism underlying the development of the disease remains controversial. There is substantial evidence suggesting a genetic basis for Paget's disease in some patients. A viral etiology of Paget's disease has been advocated. A further hypothesis implicating an immunological mechanism for this disease is based on growing evidence reviewed in the text. The presented case showed clinical and X-ray features typical of a very aggressive form of Paget's disease. We hypothesize that the extreme local aggressiveness of this case was secondary to the patient's concomitant immunosuppression due to an extended therapy following renal transplant.  相似文献   
12.
In an attempt to identify potentially lithogenic proteins, a detergent soluble extract of human renal calculi was used to produce a unique monoclonal antibody. The monoclonal antibody was found to detect the presence of a specific epitope in 77% of individually extracted kidney stones from our patients' stone bank at The Long Island Kidney Stone Unit, State University of New York, Stony Brook. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoprecipitation, and Western Blot analysis revealed this monoclonal antibody to be specific to a protein of 83,000 dalton molecular weight. A secondary source of protein reactive to the monoclonal antibody was subjected to enzyme kinetic studies, those studies suggested that the 83,000 dalton protein is a member of the protein-glutamine gammaglutamyltransferase (transglutaminase) family of enzymes. It was not determined in the present investigation whether a member of this family of enzymes initiates or is necessary for lithiasis.  相似文献   
13.
OBJECTIVE: Juvenile (virginal) hypertrophy of the breast (JHB) is a relatively rare condition leading to gigantomastia in peripubertal females. The pathology is limited usually to the breast, with otherwise normal growth and development and without any other deformities. The rapid growth of the breast (bilateral or unilateral) in adolescent girls leads to significant physical and psychological difficulties. This gigantomastia is treated surgically by breast reduction or mastectomy and its modification. Familial JHB was described only once in the literature, and its etiology is unknown. RESULTS: We report here on a familial pattern of juvenile hypertrophy of the breast accompanied by congenital anonychia. To the best of our knowledge, this is the first report of such a presentation. Our study dealt with four members of the same family, related through their fathers, enduring congenital anonychia of hands and feet with no functional limitation and who showed rapid uncontrolled breast enlargement in prepubertal age. This was severe enough to cause the curtailment of their social activity and cessation of schooling. The mothers of all four patients had normal breasts and nails, whereas their fathers had anonychia. The genetic basis for the association between the two clinical findings is yet to be determined. CONCLUSION: The four girls underwent breast reduction surgery.  相似文献   
14.
15.
Ge2Sb2Te5 (GST225) looks to be a promising material for rewritable memory devices due to its relatively easy processing and high optical and electrophysical contrast for the crystalline and amorphous phases. In the present work, we combined the possibilities of crystallization and anisotropic structures fabrication using femtosecond laser treatment at the 1250 nm wavelength of 200 nm thin amorphous GST225 films on silicon oxide/silicon substrates. A raster treatment mode and photoexcited surface plasmon polariton generation allowed us to produce mutually orthogonal periodic structures, such as scanline tracks (the period is 120 ± 10 μm) and laser-induced gratings (the period is 1100 ± 50 nm), respectively. Alternating crystalline and amorphous phases at the irradiated surfaces were revealed according to Raman spectroscopy and optical microscopy studies for both types of structures. Such periodic modulation leads to artificial optical and electrophysical anisotropy. Reflectance spectra in the near infrared range differ for various polarizations of probing light, and this mainly results from the presence of laser-induced periodic surface structures. On the other hand, the scanline tracks cause strong conductivity anisotropy for dc measurements in the temperature range of 200–400 K. The obtained results are promising for designing new GST225-based memory devices in which anisotropy may promote increasing the information recording density.  相似文献   
16.
Stiles-Crawford functions (SCF's) were measured for both eyes of an albino observer with a marked pendular nystagmus using an eye position monitoring system. Both eyes demonstrated directional sensitivity as revealed by their SCF's. The directional sensitivity of both eyes was less than that of either the foveal or parafoveal region of normal observers. In addition, there was a significant difference between the SCF's for the albino observer's two eyes. Our results suggest that the psychophysical SCF is predominately the result of the orientational distribution of groups of receptors on the retina.  相似文献   
17.
COVID-19 caused by SARS-CoV-2 is continuing to spread around the world and drastically affect our daily life. New strains appear, and the severity of the course of the disease itself seems to be decreasing, but even people who have been ill on an outpatient basis suffer post-COVID consequences. Partly, it is associated with the autoimmune reactions, so debates about the development of new vaccines and the need for vaccination/revaccination continue. In this study we performed an analysis of the antibody response of patients with COVID-19 to linear and conformational epitopes of viral proteins using ELISA, chip array and western blot with analysis of correlations between antibody titer, disease severity, and complications. We have shown that the presence of IgG antibodies to the nucleoprotein can deteriorate the course of the disease, induce multiple direct COVID-19 symptoms, and contribute to long-term post-covid symptoms. We analyzed the cross reactivity of antibodies to SARS-CoV-2 with own human proteins and showed that antibodies to the nucleocapsid protein can bind to human proteins. In accordance with the possibility of HLA presentation, the main possible targets of the autoantibodies were identified. People with HLA alleles A01:01; A26:01; B39:01; B15:01 are most susceptible to the development of autoimmune processes after COVID-19.  相似文献   
18.
ABSTRACT: BACKGROUND: Older adults receiving inpatient rehabilitation have low activity levels and poor mobility outcomes. Increased physical activity may improve mobility. The objective of this Phase II study was to evaluate the feasibility of a randomized controlled trial (RCT) of enhanced physical activity in older adults receiving rehabilitation. METHODS: Patients admitted to aged care rehabilitation with reduced mobility were randomised to receive usual care or usual care plus additional physical activity, which was delivered by a physiotherapist or physiotherapy assistant. The feasibility and safety of the proposed RCT protocol was evaluated. The primary clinical outcome was mobility, which was assessed on hospital admission and discharge by an assessor blinded to group assignment. To determine the most appropriate measure of mobility, three measures were trialled; the Timed Up and Go, the Elderly Mobility Scale and the de Morton Mobility Index. RESULTS: The protocol was feasible. Thirty-four percent of people admitted to the ward were recruited, with 47 participants randomised to a control (n = 25) or intervention group (n = 22). The rates of adverse events (death, falls and readmission to an acute service) did not differ between the groups. Usual care therapists remained blind to group allocation, with no change in usual practice. Physical activity targets were met on weekdays but not weekends and the intervention was acceptable to participants. The de Morton Mobility Index was the most appropriate measure of mobility. CONCLUSIONS: The proposed RCT of enhanced physical activity in older adults receiving rehabilitation was feasible. A larger multi-centre RCT to establish whether this intervention is cost effective and improves mobility is warranted. Trial registration The trial was registered with the ANZTCR (ACTRN12608000427370).  相似文献   
19.
20.
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