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   528篇
  免费   33篇
  国内免费   2篇
耳鼻咽喉   5篇
儿科学   12篇
妇产科学   5篇
基础医学   65篇
口腔科学   8篇
临床医学   74篇
内科学   152篇
皮肤病学   14篇
神经病学   62篇
特种医学   21篇
外科学   50篇
综合类   3篇
预防医学   18篇
眼科学   20篇
药学   36篇
中国医学   3篇
肿瘤学   15篇
  2023年   2篇
  2022年   4篇
  2021年   13篇
  2020年   10篇
  2019年   8篇
  2018年   17篇
  2017年   13篇
  2016年   17篇
  2015年   12篇
  2014年   22篇
  2013年   29篇
  2012年   42篇
  2011年   46篇
  2010年   17篇
  2009年   17篇
  2008年   37篇
  2007年   27篇
  2006年   30篇
  2005年   28篇
  2004年   29篇
  2003年   28篇
  2002年   18篇
  2001年   15篇
  2000年   20篇
  1999年   17篇
  1998年   4篇
  1997年   3篇
  1996年   2篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   11篇
  1991年   5篇
  1990年   1篇
  1989年   5篇
  1988年   2篇
  1985年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1973年   1篇
  1972年   1篇
排序方式: 共有563条查询结果,搜索用时 15 毫秒
1.
2.
In an earlier publication, various transformations used in hearing aid research and its application were summarized. As a result of continued interest and requests, additional transfer functions are provided in this addendum.  相似文献   
3.
Plasma protein adsorption pattern on characterized ceramic biomaterials.   总被引:1,自引:0,他引:1  
The protein/biomaterial interactions of three biomaterials used in hard tissue surgery were studied in vitro. A dynamic flow system and two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) were used to investigate the adsorption of proteins from diluted human plasma on hydroxyapatite, alumina and zirconia, with regard to total protein binding capacity, relative binding capacity for specific proteins and flow-through and desorption patterns. The ceramics were characterized regarding physicochemical properties; namely, chemical composition by elementary analyses and specific surface, pore volume and pore size distribution using the BET-method and Hg-porosimetry. The materials were found to adsorb a surprisingly low amount of plasma proteins, leaving more than 70% of the surface free. The cellular response will therefore be highly affected by the physico-chemical properties of the material, in contrast to a surface fully covered with proteins. Regarding the adsorption of proteins, most proteins exhibited similar flow-through patterns on the three adsorbents. The exceptions with different flow-through patterns were apolipoprotein D (Apo D), apolipoprotein J (Apo J), complement factor C1s (C1s), complement factor C3 (C3), ceruloplasmin, fibrinogen, alpha1 B glycoprotein and alpha2 HS glycoprotein and serum retinal-binding protein (SRBP). The role of these proteins on acceptance or rejection of implants has to be investigated.  相似文献   
4.
Weaning a patient from mechanical ventilation is occasionally a difficult process complicated by the patient's emotional state. Anxiety, agitation, depression and other emotional disturbances can start a vicious circle between fear of losing breath and dyspnea that impairs the process of withdrawing ventilatory support. A biocybernetic loop model is suggested that integrates psychological variables (e.g., capacity of self-control, self-confidence, sense of self-efficacy) as important factors for a successful weaning. The paradigm of biofeedback is regarded as a suited approach to strengthen these psychological factors. It means the externalization of physiological functions especially of those from the autonomous nervous system so that a patient becomes aware of them. In the case of the ventilated patient, it is assumed that the transformation of the respiratory activities into perceptible (acoustic and visual) signals supports the patient's self-controlling behaviour during the weaning process. He gets positive reinforcement for his efforts to influence his breathing intentionally and, by continuous and immediate information, he regains self-confidence to control his somatic functions effectively. The application of biofeedback is mainly described in single case studies. They all report a decrease in the respiratory rate and an increase in the tidal volume. The need for a controlled study is suggested that would answer the question of whether biofeedback is an appropriate psychological tool to facilitate the weaning process in mechanically ventilated patients.  相似文献   
5.
Type 2 diabetes (T2D) and Alzheimer??s disease (AD) are two progressive disorders with high prevalence worldwide. Polymorphisms in tumor necrosis factor-alpha (TNF-??) and apolipoprotein E (ApoE) genes might be associated with both T2D and AD, representing possible genetic markers for the development of the AD in subjects with T2D. The aim was to determine ApoE and G-308A TNF-?? gene polymorphisms in unrelated Croatian Caucasians: 207 patients with sporadic AD, 196 T2D patients and 456 healthy controls. Patients with AD had higher frequency of ApoE4 allele compared to T2D patients and controls. The significant association, observed between ApoE2 allele and T2D, disappeared after the data were adjusted for age and sex. The genotype or allele frequencies of G-308A TNF-?? gene polymorphism were similar among the patients with AD, T2D and healthy controls. In conclusion, these results do not support the hypothesis that the A allele of G-308A TNF-?? gene polymorphism is associated either with AD or T2D. Our data confirm the association between the ApoE4 allele and AD, and point out the E2 allele of ApoE gene as the possible risk factor for T2D.  相似文献   
6.
Aim: Fas membrane-associated polypeptide antigen is a receptor molecule responsible for apoptosis-mediated signals. In animal models of acute viral hepatitis, apoptosis of hepatocytes is mediated by Fas-death receptors; therefore, the aim of this study was to evaluate the effect of interferon (IFN)-alpha on apoptotic markers and nuclease activity against different coding and non-coding single and double stranded RNAs during Fas-induced liver apoptosis. Methods: An in vivo experiment was performed with simultaneous administration of anti-Fas (CD95) antibodies and IFN-alpha, and an in vitro experiment was performed in hepatocyte cultures treated with anti-Fas antibodies and IFN-alpha. Results: Detection of apoptosis using Annexin V-FITC/propidium iodide, Bcl-2 and Bax expression in hepatocyte cultures confirmed the appearance of early apoptotic events and progression toward late apoptosis after anti-Fas antibody treatment. IFN-alpha had a tendency to retard the apoptosis process in Fas-induced apoptosis by increasing the number of viable cells and decreasing the number of cells in late apoptosis, by increasing the percentage of Bcl-2 positive cells, by decreasing the percentage of Bax positive cells, and by decreasing the nuclease activity compared to the anti-Fas antibody treated group. Total DNA and RNA concentration was much reduced in the Fas group and DNA fragmentation assay provided evidence for increased DNA degradation. Enhanced nuclease activity against DNA, rRNA, poly(A), poly(C), poly(U), poly(I:C), and poly(A:U) was manifested in the anti-Fas antibody treated group, except for the inhibitory-bound alkaline RNase. Conclusions: The results demonstrate that the RNA-degrading pathway in Fas-induced apoptosis can accelerate the liberation of the latent enzyme from the inhibitor complex. IFN-alpha prevented enormous, Fas-ligand induced degradation of all the substrates used in this experimental study, most probably due to similarities in the signal transduction pathways. Investigations of death receptor-induced apoptosis may lead to novel treatment combinations for patients with acute or chronic liver diseases.  相似文献   
7.
8.
9.
Mitchell PB, Johnston AK, Frankland A, Slade T, Green MJ, Roberts G, Wright A, Corry J, Hadzi‐Pavlovic D. Bipolar disorder in a national survey using the World Mental Health Version of the Composite International Diagnostic Interview: the impact of differing diagnostic algorithms. Objective: The World Mental Health Version of the Composite International Diagnostic Interview (WMH‐CIDI) DSM‐IV bipolar disorder diagnostic algorithms were recalibrated in about 2006 following evidence of over‐diagnosis of bipolar I disorder. There have been no reports of the impact of this recalibration on epidemiological findings. Method: Data were taken from the 2007 Australian National Survey of Mental Health and Wellbeing. Findings for cases identified by the recalibrated bipolar disorder definition were contrasted against those identified by the un‐recalibrated definition. Results: The 12‐month prevalence of recalibrated bipolar disorder and un‐recalibrated bipolar disorder were 0.9% and 1.7% respectively. The un‐recalibrated bipolar disorder group was younger and more likely to have never married than the recalibrated bipolar disorder group. They were also more likely to have a comorbid alcohol use disorder, substance use disorder and asthma or arthritis. While they were more likely to have at least severe interference in at least one of the Sheehan Scale domains of functioning, they were less likely to have made a suicide attempt. Similarly, they were less likely to have consulted a psychiatrist. Conclusion: It is not possible to be certain about the nature of these differences. Some may be artifactual (reflecting greater statistical power to detect differences with the larger un‐recalibrated bipolar disorder defined sample), while others may be indicative of the inclusion of a clinically distinct subpopulation with the un‐recalibrated bipolar disorder definition, thereby producing a more heterogeneous sample. These findings indicate the need for clarity in the diagnostic algorithm used in epidemiological reports on bipolar disorder using the World Mental Health Version of the Composite International Diagnostic Interview.  相似文献   
10.
The aim of this study was to analyze survival, causes of death and cardiologic predictors of sudden death in a large cohort of patients with myotonic dystrophy type 1 (DM1). The study was comprised of 171 adult DM1 patients hospitalized at the Neurology Clinic in a 20-year period. Severe electrocardiographic (ECG) abnormality included at least one of the following: rhythm other than sinus, PR interval of ?240 ms, QRS complex duration of 120 ms or more, and second-degree or third-degree atrioventricular (AV) block. Survival data were analyzed by the Kaplan–Meier test, log–rank test and Cox regression analysis. During the mean follow-up period of 9.4 ± 5.4 years, a pacemaker was implanted in 5.8% of DM1 patients and 14% of patients died. The mean age at death was 55.6 ± 12.5 years. The most common causes of death in our cohort were sudden death (41.7%) and respiratory failure (29.2%). The presence of palpitations (hazard ratio [HR] = 4.7, p < 0.05) and increased systolic blood pressure (HR = 9.8, p < 0.05) were significant predictors of sudden death. Among ECG parameters, severe ECG abnormality (HR = 4.7, p < 0.05), right bundle branch block (RBBB; HR = 3.9, p < 0.05) and bifascicular block (HR = 5.8, p < 0.05) were significant predictors of sudden death.  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