全文获取类型
收费全文 | 151篇 |
免费 | 13篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 1篇 |
基础医学 | 22篇 |
口腔科学 | 7篇 |
临床医学 | 16篇 |
内科学 | 42篇 |
皮肤病学 | 1篇 |
神经病学 | 3篇 |
特种医学 | 15篇 |
外科学 | 22篇 |
综合类 | 1篇 |
预防医学 | 20篇 |
药学 | 3篇 |
肿瘤学 | 7篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 13篇 |
2012年 | 11篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 11篇 |
2008年 | 13篇 |
2007年 | 8篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 9篇 |
2002年 | 12篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 5篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1991年 | 1篇 |
1987年 | 3篇 |
1984年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有165条查询结果,搜索用时 31 毫秒
61.
The correlations between salivary proteins and the daytime variations are not known. The present study investigated the within-subject variation of correlations and concentrations between lysozyme, IgA, IgG, IgM, albumin, amylase, and total protein in stimulated whole saliva of healthy adults in the course of a 12-h period. After several practise sessions, unstimulated and stimulated whole saliva samples were collected five times daily (at 8 a.m., 11 a.m., 2 p.m., 5 p.m., and 8 p.m.) from 30 healthy university students. Flow rate and total protein concentration were used as covariates, and gender as a between-subject factor in the MANOVA analysis. After this adjustment, there was significant within-subject variation in salivary IgA (P < 0.001), albumin (P < 0.01), amylase (P < 0.05), and total protein (P < 0.001) concentrations. Total protein correlated significantly with amylase albumin and IgA through different samplings. In addition, IgG correlated with albumin and lysozyme in the course of 12 h. On the whole, the correlations between variables remained stable during repeated samplings. In addition, rankings of subjects for the variables tended to be maintained across different samplings (P < 0.001). However, the observed within-subject variations in salivary IgA, albumin, amylase, and total protein concentrations suggest that these proteins are subject to short-term variation. 相似文献
62.
Vehmas T Oksa P Kivisaari L 《International archives of occupational and environmental health》2012,85(2):207-213
Purpose
To work out the predictive value of pathological (HR)CT signs concerning long-term mortality among those screened for lung cancer. 相似文献63.
Helena Hnninen Panu Takala Markku Mkijrvi Juha Montonen Petri Korhonen Lasse Oikarinen Jukka Nenonen Toivo Katila Lauri Toivonen 《Annals of noninvasive electrocardiology》2000,5(2):147-157
Background: Detection of myocardial ischemia was studied with multichannel exercise magneto‐cardiography (MCG). A surface gradient method was applied to analyze cardiac magnetic fields. Methods: We studied 27 patients with single vessel coronary artery disease (CAD) and 17 healthy volunteers. The MCG was recorded over anterior chest during supine bicycle ergometry. The two‐dimensional direction of the maximum spatial magnetic field gradient was determined during the ST segment and at the T‐wave apex at different phases of stress test. Results: The CAD patient group was separated from controls by the orientation of the magnetic field gradient during the ST segment at cessation of exercise (CAD 167 ± 68° vs controls 106 ± 49°; P < 0.005) and at 4 minutes postexercise, but not at rest. The‐CAD patient group was separated from controls also by the orientation of the magnetic field gradient at the T‐wave apex at 4 minutes postexercise (CAD 87 ± 60° vs controls 58 ± 18° P < 0.05), but not at rest. The change in the orientation of the field gradient at the T‐wave apex 4 minutes postexercise, compared to baseline, was greater in CAD patients (31 ± 43°) than in controls (9 ± 8° P < 0.05). This change was larger in the patient group with stenosis in the right than in the left coronary artery (P < 0.05). Conclusions: Transient acute myocardial ischemia causes well‐recognizable changes in the magnetocardiogram at the ST segment and the T wave. The orientation of the maximum spatial gradient of the magnetic field can be used as a parameter to determine these changes. 相似文献
64.
IL-2 negatively regulates IL-7 receptor alpha chain expression in activated T lymphocytes 总被引:1,自引:0,他引:1 下载免费PDF全文
Xue HH Kovanen PE Pise-Masison CA Berg M Radovich MF Brady JN Leonard WJ 《Proceedings of the National Academy of Sciences of the United States of America》2002,99(21):13759-13764
Interleukin (IL)-2 is a type I four-alpha-helical bundle cytokine that plays vital roles in antigen-mediated proliferation of peripheral blood T cells and also is critical for activation-induced cell death. We now demonstrate that IL-2 potently decreases expression of IL-7 receptor alpha chain (IL-7Ralpha) mRNA and protein. The fact that IL-7Ralpha is a component of the receptors for both IL-7 and thymic stromal lymphopoietin (TSLP) suggests that IL-2 can negatively regulate signals by each of these cytokines. Previously it was known that the IL-2 and IL-7 receptors shared the common cytokine receptor gamma chain, gamma(c), which suggested a possible competition between these cytokines for a receptor component. Our findings now suggest a previously unknown type of cross-talk between IL-2 and IL-7 signaling by showing that IL-2 signaling can diminish IL-7Ralpha expression via a phosphatidylinositol 3-kinase/Akt-dependent mechanism. 相似文献
65.
Peitsaro P Ruutu M Syrjänen S Johansson B 《Scandinavian journal of infectious diseases》2004,36(4):302-304
Expression of the viral oncogenes E6 and E7, and telomerase, was investigated, using a cell line from a mild dysplastic vaginal lesion containing human papillomavirus (HPV) type 33. During passaging of the cells, there was a change towards a cancer phenotype, and a shift from episomal to integrated HPV. Levels of hTERT (catalytic subunit of telomerase) mRNA, and telomerase activity in cells carrying episomal virus seemed constant during passaging. During passaging of cells containing integrated HPV, however, the levels of oncogene mRNA decreased, while hTERT mRNA and telomerase activity increased sharply. Thus, in those cells there is no direct correlation between changes of oncogene and telomerase expression. Conceivably, viral oncogene expression might trigger telomerase up-regulation in an early subpopulation of cells, which during subsequent passaging could be selected for. 相似文献
66.
PURPOSE: To assess the technical success and complications of Angio-Seal vascular closure device in antegrade common femoral artery (CFA) punctures. METHODS: Over a 14-month period, 55 patients (37 men; age range 37-94 years) underwent antegrade CFA Angio-Seal placement at a single center; the clinical data and angiograms were reviewed retrospectively. A total of 56 antegrade CFA punctures were made for hemostasis; 6-F Angio-Seal devices (40 model STS and 12 model VIP) were deployed in 52 CFAs, and 8-F Angio-Seal devices were deployed in 4. RESULTS: The technical success rate was 98.2% (55/56). Two (3.6%) patients developed small, non-expanding hematomas (<5 cm) during deployment of the device. There was 1 episode of device/operator failure, presumably due to extravascular deployment within soft tissue. None of the patients developed pseudoaneurysm, arterial injury, or large hematomas requiring transfusion. Small calcified plaques at the puncture site did not influence the outcome. CONCLUSION: This series suggests that Angio-Seal may be a safe and effective device for hemostasis in antegrade CFA punctures. Further randomized trials testing its risk-benefit balance in comparison to standard manual compression are warranted. 相似文献
67.
68.
We describe a novel Bayesian approach to estimate acquisition and clearance rates for many competing subtypes of a pathogen in a susceptible–infected–susceptible model. The inference relies on repeated measurements of the current status of being a non‐carrier (susceptible) or a carrier (infected) of one of the nq > 1 subtypes. We typically collect the measurements with sampling intervals that may not catch the true speed of the underlying dynamics. We tackle the problem of incompletely observed data with Bayesian data augmentation, which integrates over possible carriage histories, allowing the data to contain intermittently missing values, complete dropouts of study subjects, or inclusion of new study subjects during the follow‐up. We investigate the performance of the described method through simulations by using two different mixing groups (family and daycare) and different sampling intervals. For comparison, we describe crude maximum likelihood‐based estimates derived directly from the observations. We apply the estimation algorithm to data about transmission of Streptococcus pneumonia in Bangladeshi families. The computationally intensive Bayesian approach is a valid method to account for incomplete observations, and we found that it performs generally better than the simple crude method, in particular with large amount of missing data. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
69.
70.
Ari Laiho Panu Hiekkataipale Janne Ruokolainen Olli Ikkala 《Macromolecular chemistry and physics.》2009,210(15):1218-1223
A self‐assembled lamellar‐within‐lamellar structure of a side chain liquid crystalline diblock copolymer was shear aligned to induce overall alignment and to direct the smectic layer orientation within the copolymer lamellae. The copolymer consisted of a polystyrene block and a poly(methyl methacrylate) block bearing cholesteryl mesogens with only short oxycarbonyloxyethyl spacers separating the mesogens from the backbone. Upon shearing, the copolymer lamellae exhibited uniaxial alignment whereas the smectic layers of the mesogens showed coexisting perpendicular and parallel orientations with respect to the copolymer lamellae. The fraction of the parallel oriented domains could be systematically increased by tuning the oscillation frequency and strain amplitude.