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   1194篇
  免费   66篇
  国内免费   10篇
耳鼻咽喉   16篇
儿科学   69篇
妇产科学   38篇
基础医学   101篇
口腔科学   47篇
临床医学   151篇
内科学   199篇
皮肤病学   30篇
神经病学   124篇
特种医学   27篇
外科学   144篇
综合类   45篇
预防医学   65篇
眼科学   66篇
药学   80篇
中国医学   15篇
肿瘤学   53篇
  2023年   12篇
  2022年   20篇
  2021年   25篇
  2020年   21篇
  2019年   26篇
  2018年   37篇
  2017年   22篇
  2016年   23篇
  2015年   32篇
  2014年   46篇
  2013年   56篇
  2012年   81篇
  2011年   86篇
  2010年   52篇
  2009年   35篇
  2008年   68篇
  2007年   72篇
  2006年   65篇
  2005年   95篇
  2004年   88篇
  2003年   51篇
  2002年   57篇
  2001年   19篇
  2000年   23篇
  1999年   12篇
  1998年   10篇
  1997年   6篇
  1996年   8篇
  1995年   5篇
  1994年   3篇
  1993年   3篇
  1992年   16篇
  1991年   7篇
  1990年   13篇
  1989年   9篇
  1988年   5篇
  1987年   4篇
  1985年   12篇
  1983年   2篇
  1982年   2篇
  1980年   4篇
  1979年   4篇
  1977年   2篇
  1976年   2篇
  1975年   2篇
  1974年   4篇
  1973年   3篇
  1972年   7篇
  1971年   2篇
  1969年   3篇
排序方式: 共有1270条查询结果,搜索用时 31 毫秒
1.
The aim of this study was to evaluate the influence of vascular endothelial growth factor (VEGF) on renal function and on development of interstitial fibrosis (IF) in renal allografts. Tubular and interstitial expressions of VEGF and TNF-α, and density of macrophages in the interstitium were examined in 92 patients with nonrejected kidneys, acute rejection (AR), chronic allograft nephropathy (CAN), borderline changes (BC) and acute cyclosporin A (CsA) toxicity. Follow-up biopsy specimens from patients with AR and BC were evaluated for development of IF. A significant difference in tubular and interstitial VEGF expressions was found between patients with AR, BC, CAN and CsA toxicity (p < 0.001). Macrophage infiltration was positively correlated with VEGF and TNF-α expressions (p < 0.001). VEGF expression increased with increasing expression of TNF-α (p < 0.001). Renal function in first 6 months after initial biopsy was better in patients with marked tubular VEGF expression (p < 0.01); however, in follow-up, development of IF and graft loss was found earlier in these patients (p < 0.01 and p < 0.05, respectively). Increased renal VEGF expression has protective properties immediately following renal allograft but allows for increased risk of early IF, and therefore poor graft outcome in the long term.  相似文献   
2.
应用静脉注丙球(IVIG),配合抗生素(An)治疗重症感染新生儿12例,在观察疗效及不良反应的同时,通过检测患儿治疗前后T细胞亚群及白细胞介素Ⅱ(IL-2)产生水平的变化,观察IVIG对细胞免疫功能的影响。结果显示:患儿CD_3~+、CD_4~+、CD_8~+细胞及IL-2产生水平均明显低于正常同龄新生儿。经IVIG+An及单用An治疗后,T细胞各亚群及IL-2水平均明显增高。IVIG组与An组比较,诒疗后IVIG组CD_4~+细胞明显高于An组,IL-2水平也较An组为高,但无统计学意义。疗效观察,中毒症状及原发病体征好转消失时间IVIG组较An组明显缩短。本文还就IVIG对细胞免疫功能影响的可能机制进行了讨论。  相似文献   
3.
Esthesioneuroblastoma is an uncommon malignant neoplasm that arises from olfactory mucosa, often with intracranial extension.A case report of the youngest victim in the literature (2-year-old boy) is presented.  相似文献   
4.
5.
DNA methods have resulted in improved renal allograft survival rates in cadaveric renal transplantation. This paper describes the impact of DNA typing by PCR-SSP on a living-related renal transplant (LRRT) programme. It evaluates error rates in serology, acute rejections, graft function and survival rates between the two typing methods. Serological typing was carried out on CTS 120 antisera Class 1, 60 antisera Class 2, 72 antisera Terasaki Class 1 and 72 antisera Class 2 antigens. Low-resolution PCR-SSP typing was carried out by 24 primers for HLA-A, 48 for HLA-B and 24 for HLA-DR. Of the 585 transplants: 159 (Group I) were serology based; 172 were serology and PCR-SSP based for HLA-DR (Group II); and 254 were serology and PCR-SSP based for HLA-A and -B, and only PCR-SSP based for HLA-DR (Group III). Error rates in serology compared with PCR-SSP were 24% for HLA-A, 16% for HLA-B and 35% for HLA-DR. Acute rejections were 39%, 30% 26% in Groups I, II and III, respectively ( P= 0.02). Graft function of serum creatinine <1.5 mg/dl at 1 year was found in 26% of the Group I patients compared with 48% of those in Group III ( P <0.0001). One- and 3-year graft survival was 93% and 87% for Group II compared with 81% and 69% for Group I, respectively ( P= 0.0001). Matching by this combination of serology and PCR-SSP is not only economical for a developing country but also improves graft survival by 12% and 18% at 1 and 3 years, respectively.  相似文献   
6.
目的 评价利培酮治疗精神分裂症的疗效和副作用。方法 将 5 9例精神分裂症住院病人随机分为利培酮 ( 4 mg/d)1组 ( 1 9例 )、利培酮 ( 6 mg/d) 2组 ( 2 0例 )和氯丙嗪组 ( 2 0例 ) ,治疗 8周。用阳性与阴性症状量表 ( PANSS)评定疗效 ,用副反应量表 ( BPRS)及锥体外系副反应量表 ( TESS)评定副反应。结果 利培酮两个剂量组与氯丙嗪组之间疗效无显著性差异。在认知因子、阴性因子、PANSS总分减分率方面 ,利培酮组与氯丙嗪组有显著性差异。利培酮的副反应有锥体外系反应、失眠、头昏等。结论 利培酮是一种安全有效的抗精神病药物 ,在改善认知功能和阴性症状方面 ,利培酮优于氯丙嗪 ,少数病例可出现锥体外系反应。  相似文献   
7.
The association of disseminated magnesium silicate talc granulomatosis and acquired immunodeficiency syndrome is reported in a male homosexual who used intravenous drugs and who died of overwhelming cytomegalovirus (CMV) infection. Autopsy findings included widespread deposition of talc crystals in the lungs, liver, lymph nodes, bone marrow, and spleen. Typical CMV inclusions were seen in the lungs, kidneys, adrenal glands, gastrointestinal tract, and right eye. There was no evidence of malignancy. Analysis of peripheral blood neutrophil function revealed impaired chemotaxis and chemokinesis, but opsonophagocytosis had remained normal. The CMV infection in the small bowel was extensive and resulted in severe destruction of the muscularis propria and neural plexi, leading to marked dilatation and persistent diarrhea. The terminal course was marked by intractable hypotension, pneumonitis, and malnutrition, which could be attributed respectively to CMV involvement of the adrenal glands, lungs, and small bowel. The etiology and possible role of systemic talc granulomatosis in the development of immunosuppressive illness is reported herein.  相似文献   
8.
The blind panel collected for the 8th Human Leucocyte Differentiation Antigens Workshop (HLDA8; ) included 49 antibodies of known CD specificities and 76 antibodies of unknown specificity. We have identified groups of antibodies showing similar patterns of reactivity that need to be investigated by biochemical methods to evaluate whether the antibodies within these groups are reacting with the same molecule. Our approach to data analysis was based on the work of Salganik et al. (in press) [Salganik, M.P., Milford E.L., Hardie D.L., Shaw, S., Wand, M.P., in press. Classifying antibodies using flow cytometry data: class prediction and class discovery. Biometrical Journal].  相似文献   
9.
Twenty individuals with autism or related disorders underwent chromosome analysis and physical examinations with documentation of minor anomalies. Chromosome anomalies were identified in 3: 2 had the heritable folate sensitive fra(2) (q13) site and 1 had an inv(9) (p11q12). No heritable chromosome variants or anomalies were seen in 20 age and sex-matched control individuals. When patients with the fra(2) were excluded from analyses, there was no difference in the frequency of chromosome breaks and/or gaps between the study group and control group. The results of this study suggest that heritable folate sensitive fragile sites and other chromosome variants may be more commonly seen in individuals with autism or related disorders in childhood than in the general population.  相似文献   
10.
The purpose of this study was to determine the prevalence of suicide attempts, and to identify the risk factors for suicide attempts in Turkish children and adolescents between the ages 10 and 20 years. Multi-step, stratified, cluster sampling was used. A stratified sample of 4256 students was selected as representative of the city's school children population. Data was obtained with a pair of structured questionnaires designed to evaluate the presence and risk factors of suicide attempts, both in the children and adolescents and their parents. These questionnaires investigated family environment, subject characteristics, and various risk factors for suicide attempts. Child Beck Depression Inventory (CBDI) was administered to all children and adolescents. After the data quality control process, the study sample was reduced to 4143 children and adolescents. Children and adolescents were divided two groups according to the experience or non-experience of suicide attempts: group 1 (n=80) and group 2 (n=4063), respectively. Three categories of independent variables were assessed: adolescent, family, and socioeconomic characteristics. Logistic regression models were based on the children and adolescents and on parent reports. The prevalence of suicide attempts as reported by the children and adolescents was 1.93% (n=80).The mean age of group 1 was higher than that of group 2 (p=0.002, t=-3.172), as was the mean score of CBDI (p=0.000, t=-9.083). Logistic regression analysis indicated that having problems with parents, using illicit drugs, and psychiatric problems in relatives best predicted suicide attempts in Turkish children and adolescents.  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