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   50857篇
  免费   2993篇
  国内免费   246篇
耳鼻咽喉   630篇
儿科学   1170篇
妇产科学   1217篇
基础医学   7055篇
口腔科学   1499篇
临床医学   5571篇
内科学   10967篇
皮肤病学   797篇
神经病学   5010篇
特种医学   1761篇
外科学   6301篇
综合类   325篇
一般理论   44篇
预防医学   3615篇
眼科学   805篇
药学   3441篇
  1篇
中国医学   59篇
肿瘤学   3828篇
  2023年   321篇
  2022年   631篇
  2021年   1143篇
  2020年   745篇
  2019年   979篇
  2018年   1194篇
  2017年   1069篇
  2016年   1254篇
  2015年   1309篇
  2014年   1738篇
  2013年   2503篇
  2012年   3789篇
  2011年   3979篇
  2010年   2365篇
  2009年   2155篇
  2008年   3287篇
  2007年   3589篇
  2006年   3202篇
  2005年   3260篇
  2004年   2998篇
  2003年   2796篇
  2002年   2565篇
  2001年   425篇
  2000年   348篇
  1999年   479篇
  1998年   561篇
  1997年   459篇
  1996年   407篇
  1995年   346篇
  1994年   304篇
  1993年   308篇
  1992年   234篇
  1991年   228篇
  1990年   208篇
  1989年   220篇
  1988年   195篇
  1987年   171篇
  1986年   177篇
  1985年   210篇
  1984年   181篇
  1983年   166篇
  1982年   192篇
  1981年   159篇
  1980年   139篇
  1979年   112篇
  1978年   122篇
  1977年   131篇
  1976年   94篇
  1975年   107篇
  1974年   81篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
103.
Chronic renal failure triggered by calcineurin inhibitor (CNI)-based immunosuppression is a common complication after cardiac transplantation. Sirolimus and mycophenolate mofetil (MMF) are 2 newer immunosuppressive agents with no documented nephrotoxic side effects. This case report describes a patient with ongoing chronic renal failure 10 months after cardiac transplantation on cyclosporine-based immunosuppressive therapy. Conversion of the immunosuppressive regimen from cyclosporine to sirolimus and MMF resulted in freedom from acute rejection, excellent cardiac graft function and consistently improved renal function. This case illustrates the beneficial potential of sirolimus and MMF as CNI-free and safe long-term immunosuppression in a patient with chronic renal failure after heart transplantation.  相似文献   
104.
105.
106.
Twenty-two members of 18 families with autism have been examined for the presence of mutations and abnormal methylation in the FMR-1 region at Xq27.3. All patients fulfilled diagnostic criteria of infantile autism. A characteristic pattern of insertion and methylation were detected after Southern blot analysis in 7 autistic individuals expressing the fragile site at Xq27.3. Normal DNA patterns were observed in 15 autistic boys cytogenetically negative for the fragile site. The results indicate a lack of involvement of the FMR-1 region in infantile autists negative for fragile X expression. © 1992 Wiley-Liss, Inc.  相似文献   
107.
We present evidence showing that paraxanthine (1,7-dimethylxanthine), the main metabolite of caffeine in man, displaces the binding of [3H]SCH 23390, a radioligand which selectively labels dopamine D-1 receptors when used at low concentrations, from striatal membranes of the rat. The displacement was competitive and indicated the existence of two affinity states (Hill coefficient = 0.49; K(high) = 0.15 microM; K(low) = 95.9 microM, %R(high) = 32.4). When the stable GTP analog Gpp(NH)p was included, the displacement curve indicated the presence of only the low-affinity state (Hill coefficient = 1.16; Ki = 72.1 microM). However, paraxanthine did not displace the specific binding of [3H]spiperone. After injection of 30 mg/kg s.c. of caffeine, a maximum of 10 microM of paraxanthine was found in striatal homogenates, which could be sufficient to occupy dopamine D-1 receptors. Our results suggest that a dopaminergic action of paraxanthine could be involved in the behavioural stimulation produced by caffeine.  相似文献   
108.
Advances in biomedical science have resulted in dramatic improvementsin the medical care of chronically ill and handicapped children.Past measurement problems have resulted in a lack of clarityregarding the psychological adjustment of these children. Themothers of 270 chronically ill and handicapped children wereadministered the Child Behavior Checklist in an attempt to identifypatterns of behavioral functioning across six pediatric chronicdisorders: juvenile diabetes, spina bifida, hemophilia, chronicobesity, juvenile rheumatoid arthritis, and cerebral palsy.In general, it was found that children in all chronic disordergroups were perceived by their mothers as evidencing on theaverage more behavioral and social competence problems thanexpected based on norms for children in general. However, theirbehavioral and social adjustment was reported as better thanthat of a normative sample of children referred to mental healthclinics. There were essentially no differences between childrenwith different chronic disorders in terms of behavior problemsand social competence. The results were taken to support theview that these children were as a group at risk for adjustmentproblems. They were also discussed in terms of the noncategorialapproach, which suggests that similar psychosocial challengesare faced across pediatric chronic physical disorders.  相似文献   
109.
110.
The role of human spumaretrovirus (HSRV) infections in the pathogenesis of multiple sclerosis (MS) was investigated with recombinant HSRV env-specific enzyme-linked immunosorbent assay. The presence of HSRV antibodies was determined in pairs of serum and cerebrospinal fluid (CSF) samples from 60 MS patients. In 7 of these patients serial serum and CSF samples were obtained in relation to the clinical activity of the disease during a period of 2 years. No increased antibody reactivity was demonstrable in the MS population compared with 14 aseptic meningitis patients, 50 blood donors and 16 healthy controls. Slightly elevated levels of antibodies were demonstrable in serum and/or CSF in 4 MS patients but also in 1 patient with aseptic meningitis, 1 blood donor and 1 child. No marked serum or CSF HSRV antibody fluctuation was observed in the MS patients followed longitudinally. Thus, this study does not support the involvement of HSRV in the pathogenesis of MS.  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