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   326篇
  免费   29篇
耳鼻咽喉   2篇
儿科学   10篇
妇产科学   4篇
基础医学   40篇
口腔科学   7篇
临床医学   50篇
内科学   92篇
皮肤病学   4篇
神经病学   36篇
特种医学   7篇
外科学   33篇
综合类   1篇
预防医学   17篇
眼科学   14篇
药学   22篇
中国医学   1篇
肿瘤学   15篇
  2023年   3篇
  2022年   9篇
  2021年   13篇
  2020年   8篇
  2019年   10篇
  2018年   14篇
  2017年   14篇
  2016年   16篇
  2015年   11篇
  2014年   25篇
  2013年   18篇
  2012年   34篇
  2011年   24篇
  2010年   23篇
  2009年   14篇
  2008年   19篇
  2007年   17篇
  2006年   16篇
  2005年   20篇
  2004年   19篇
  2003年   8篇
  2002年   4篇
  2001年   4篇
  2000年   1篇
  1998年   1篇
  1991年   2篇
  1990年   2篇
  1989年   5篇
  1974年   1篇
排序方式: 共有355条查询结果,搜索用时 15 毫秒
1.
Tablets of either microsized or ultramicrosized griseofulvin (2 x 125 mg), were administered to 6 healthy volunteers of either sex just before a breakfast containing 4o g. of butter. The plasma concentration of griseofulvin were determined 1, 3, 5, 7, 9, 24, and 32 h. after dosing using a spectrofluorometric method, and pharmacokinetic parameters (Cp max, t max, AUC 0 - greater than 32) were calculated. These parameters were found to be; Cp max = 0.0.681 +/- 0.1 mu/ml, t max. = 2.51 +/- 0.33 h. and AUC = 14.14 +/- 2.33 micrograms h/ml for microsized tablets and Cp max = 0.80 +/- 0.08 +/- g/ml, t max = 2.44 +/- 0.54 and AUC = 16.25 +/- 1.16 microgram h/ml for ultramicrosized tablets. Our results show that mean peak plasma level and AUC (0 - greater than 32) are only slightly higher for the ultramicrosized preparation and the time to peak plasma level is similar in two preparations. Therefore, it is concluded that coadministration of griseofulvin with food will tend to reduce the difference between the bioavailability of the two type of preparations.  相似文献   
2.
Children and young people are seen as fundamental to the design and delivery of clinical research as active and reflective participants. In Europe, involvement of children and young people in clinical research is promoted extensively in order to engage young people in research as partners and to give them a voice to raise their own issues or opinions and for their involvement in planning and decision making in addition to learning research skills. Children and young people can be trained in clinical research through participation in young person advisory groups (YPAGs). Members of YPAGs assist other children and young people to learn about clinical research and share their experience and point of view with researchers, thereby possibly influencing all phases of research including the development and prioritization of research questions, design and methods, recruitment plans, and strategies for results dissemination. In the long term, the expansion of YPAGs in Europe will serve as a driving force for refining pediatric clinical research. It will help in a better definition of research projects according to the patients’ needs. Furthermore, direct engagement of children and young people in research will be favorable to both researchers and young people.  相似文献   
3.
Collagen gels are promising scaffolds to prepare an implant for cartilage repair but several parameters, such as collagen concentration and composition as well as cell density, should be carefully considered, as they are reported to affect phenotypic aspects of chondrocytes. In this study we investigated whether the presence of collagen type I or II in gel lattices affects matrix contraction and relative gene expression levels of matrix proteins, MMPs and the subsequent degradation of collagen by goat articular chondrocytes. Only floating collagen I gels, and not those attached or composed of type II collagen, contracted during a culture period of 12 days. This coincided with an upregulation of both Mmp13 and ?14 gene expression, whereas Mmp1 expression was not affected. The release of hydroxyproline in the culture medium, indicating matrix degradation, was increased five‐fold in contracted collagen I gels compared to collagen II gels without contraction. Furthermore, blocking contraction of collagen I gels by cytochalasin B inhibited Mmp13 and ?14 expression and the release of hydroxyproline. The expression of cartilage‐specific ECM genes was decreased in contracted collagen I gels, with increased numbers of cells with an elongated morphology, suggesting that matrix contraction induces dedifferentiation of chondrocytes into fibroblast‐like cells. We conclude that the collagen composition of the gels affects matrix contraction by articular chondrocytes and that matrix contraction induces an increased Mmp13 and ?14 expression as well as matrix degradation. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
4.

Background and Aims  

Among the ethnic groups, the age-standardized incidence rate of colorectal cancer (CRC) is highest among African-Americans. The majority of CRC arise from preexisting adenoma. It is shown that 30% of the US adult population has adenomas. The potential risk of malignant transformation in adenomas differs by specific pathologic and clinical characteristics that we aimed to study in AAs.  相似文献   
5.
Type II deiodinase (D2) plays a key role in regulating thyroid hormone-dependent processes in, among others, the central nervous system (CNS) by accelerating the intracellular conversion of T4 into active T3. Just like the well-known daily rhythm of the hormones of the hypothalamo-pituitary-thyroid axis, D2 activity also appears to show daily variations. However, the mechanisms involved in generating these daily variations, especially in the CNS, are not known. Therefore, we decided to investigate the role the master biological clock, located in the hypothalamus, plays with respect to D2 activity in the rat CNS as well as the role of one of its main hormonal outputs, i.e. plasma corticosterone. D2 activity showed a significant daily rhythm in the pineal and pituitary gland as well as hypothalamic and cortical brain tissue, albeit with a different timing of its acrophase in the different tissues. Ablation of the biological clock abolished the daily variations of D2 activity in all four tissues studied. The main effect of the knockout of the suprachiasmatic nuclei (SCN) was a reduction of nocturnal peak levels in D2 activity. Moreover, contrary to previous observations in SCN-intact animals, in SCN-lesioned animals, the decreased levels of D2 activity are accompanied by decreased plasma levels of the thyroid hormones, suggesting that the SCN separately stimulates D2 activity as well as the hypothalamo-pituitary-thyroid axis.  相似文献   
6.
Based on clinical studies daily plasma exchange (PE) has become the first-choice therapy for thrombotic thrombocytopenic purpura (TTP) since 1991. Recent findings may explain its effectiveness, which particularly may include supply of ADAMTS-13 and removal of anti-ADAMTS-13 autoantibodies and unusually large von Willebrand factor (VWF) multimers. The most preferable PE regimens as well as replacement fluids are discussed and treatment-related adverse reactions are summarized. Proposals for a potential reduction of their frequency and for improvement of treatment efficiency are given. These suggestions are partially based on the experience of our institution in adult patients with severe ADAMTS-13 deficiency (<5% activity), and include (1) continuous calcium-gluconate infusion during PE in order to reduce citrate-related adverse reactions; (2) the evaluation of solvent/detergent-treated (S/D) plasma as replacement fluid in order to reduce adverse events due to fresh frozen plasma (FFP); (3) the evaluation of immunoadsorption in order to increase procedural efficiency in autoantibody removal; and (4) the substitution of ADAMTS-13 by means of recombinant drug instead of plasma.  相似文献   
7.
Objectives. To identify risk factors associated with mortality in adult patients with Eisenmenger syndrome and to assess the effect of left ventricular dysfunction on mortality in these patients. Methods and Results. One hundred twenty‐two adult patients with Eisenmenger syndrome were retrospectively evaluated for signs and symptoms of heart failure, and underwent electrocardiography and laboratory investigations. Available echocardiograms were analyzed and left ventricular function was assessed both qualitatively and quantitatively. There were 47 deaths at 37.8 ± 12.0 years of age. On univariate analysis clinical signs and symptoms of heart failure, right ventricular hypertrophy on electrocardiography, wide QRS (QRS duration >130 milliseconds), and left ventricular dysfunction (left ventricular ejection fraction [LVEF] <50%) on echocardiography were associated with mortality. On multivariate analysis, signs and symptoms of heart failure, right ventricular hypertrophy on electrocardiography, and LVEF <50% remained strong predictors of death. Conclusions. Signs and symptoms of heart failure predict mortality in patients with Eisenmenger syndrome. Furthermore, patients with left ventricular dysfunction (LVEF <50%) have higher mortality. A combination of signs and symptoms of heart failure, right ventricular hypertrophy on electrocardiography, and left ventricular dysfunction on echocardiography provides the most powerful predictor of death in patients with Eisenmenger syndrome.  相似文献   
8.
9.
Stress hyperglycemia and acute graft-versus-host disease (GVHD), the major early complication of hematopoietic stem cell transplantation (HSCT), are both associated with excessive release of inflammatory cytokines. We investigated whether new-onset hyperglycemia immediately after HSCT predicts acute GVHD. We studied nondiabetic adult recipients of human leukocyte antigen-matched HSCT (peripheral blood stem cells) for acute leukemia. Using mean morning serum glucose on Days 1–10, we classified hyperglycemia as: mild (6.11–8.33 mmol/L), moderate (8.34–9.98), and severe (minimum of 9.99). Subjects who were GVHD‐free on Day 10 were followed during Days 11–100 for grades II–IV acute GVHD or competing event. Evaluation utilized cumulative incidence-based proportional hazards regression. Subjects (n?=?328) were age 18–74, median of 49 years. Per body mass index (BMI)—25.0 % were obese (BMI, 30–48), 33.8 % overweight (25 to <30), 30.8 % normal weight (21 to <25), and 10.4 % lean (18 to <21). Mild, moderate, or severe hyperglycemia occurred during Days 1–10 in 50.0, 21.3, and 16.8 % of subjects, respectively. Cumulative incidence on Day 100 was 44.8 (±2.8)?% acute GVHD and 7.9 (±1.5)?% competing event. Among normal-to-overweight subjects (n?=?212), severe hyperglycemia developed in 14.2 % (n?=?30) and more than doubled the risk of acute GVHD (hazards ratio, 2.71; 95 % CI, 1.58–4.65—adjusted for donor/recipient characteristics, prophylactic regimen, and mucositis). In contrast, among obese subjects (n?=?82), severe hyperglycemia developed in 30.5 % (n?=?25) but did not significantly affect risk of GVHD. (No lean subjects (n?=?34) developed severe hyperglycemia.) Hyperglycemia that was less than severe had an effect indistinguishable from normoglycemia. In nondiabetic patients, severe hyperglycemia immediately after allogeneic HSCT indicates increased likelihood of acute GVHD. This association is absent in obese patients, who may be primed by obesity-induced inflammation to develop severe hyperglycemia even without experiencing the cytokine storm that is essential to GVHD pathogenesis.  相似文献   
10.
Autologous stem cell transplantation (ASCT) is applied to consolidate first remission in patients with acute myeloid leukaemia (AML). However, outcome after ASCT widely varies among AML patients. We analyzed the prognostic significance of haematological recovery for neutrophils [absolute neutrophil count (ANC) >1·0 × 109/l] and platelets (platelet count >20·0 × 109/l), stratifying at day 20 after ASCT in 88 consecutive and homogeneously treated AML patients in first remission. We observed that patients with delayed recovery had better overall survival (OS; ANC: P < 0·0001 and platelets: P = 0·0062) and time to progression (TTP; ANC: P = 0·0003 and platelets: P = 0·0125). Delayed recovery was an independent marker for better OS and TTP in a multivariate analysis including age, gender, number of transfused CD34+ cells, cytogenetics, FLT3‐internal tandem duplication and NPM1 mutation. Our results suggest that delayed neutrophil and platelet recovery is associated with longer OS and TTP in AML patients consolidated with ASCT in first remission.  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