全文获取类型
收费全文 | 245篇 |
免费 | 22篇 |
专业分类
儿科学 | 2篇 |
妇产科学 | 2篇 |
基础医学 | 34篇 |
口腔科学 | 3篇 |
临床医学 | 53篇 |
内科学 | 10篇 |
神经病学 | 11篇 |
特种医学 | 9篇 |
外科学 | 87篇 |
综合类 | 10篇 |
预防医学 | 39篇 |
药学 | 3篇 |
肿瘤学 | 4篇 |
出版年
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 10篇 |
2012年 | 12篇 |
2011年 | 18篇 |
2010年 | 12篇 |
2009年 | 10篇 |
2008年 | 13篇 |
2007年 | 10篇 |
2006年 | 7篇 |
2005年 | 7篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1997年 | 3篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1966年 | 2篇 |
1948年 | 1篇 |
1944年 | 1篇 |
1943年 | 1篇 |
1942年 | 1篇 |
1939年 | 1篇 |
1937年 | 1篇 |
1936年 | 1篇 |
1935年 | 2篇 |
1934年 | 1篇 |
1933年 | 3篇 |
1932年 | 1篇 |
1931年 | 3篇 |
1930年 | 4篇 |
1929年 | 2篇 |
排序方式: 共有267条查询结果,搜索用时 15 毫秒
1.
Michael M. Morlock Veronika Bonin Gerd Müller Erich Schneider 《European journal of applied physiology》1997,76(1):75-80
This study was designed to investigate the relationship between trunk muscle fatigue and associated changes in the electromyographic (EMG) signals during a dynamic iso-inertial test. Eleven subjects performed dynamic trunk flexion/extension movements against 40% maximum voluntary contraction (MVC) torque until exhaustion in a tri-axial trunk dynamometer. EMG parameters in the time and frequency domain were studied by analysing changes of the signal amplitudes and the spectral density (using the zero-crossing-rate and the median frequency). The kinematics of the movement were analysed according to the movement velocities and the deviations from the required movement plane. The flexion and extension velocities decreased from the beginning to the end of the test. Movement deviations from the sagittal plane into the frontal and transverse plane increased with increasing test duration, as did the EMG amplitude. The median frequency during periods with maximum muscle activity decreased, as did the zero-crossing-rate. The increase in amplitude and decrease in median frequency were more pronounced in the trunk flexors than in the trunk extensors. The parameters of median frequency, zero-crossing-rate and amplitude seem to be sensitive identifiers of muscle fatigue during well-controlled dynamic contractions. While the kinematic data did not yield any information on the mechanisms of the fatigue, changes in the EMG parameters demonstrated that the duration of the test was limited by the fatigue of the trunk flexors. 相似文献
2.
Temperature-mediated heteroduplex analysis for detection of pncA mutations associated with pyrazinamide resistance and differentiation between Mycobacterium tuberculosis and Mycobacterium bovis by denaturing high- performance liquid chromatography
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mohamed AM Bastola DR Morlock GP Cooksey RC Hinrichs SH 《Journal of clinical microbiology》2004,42(3):1016-1023
The goal of this study was to apply temperature-mediated heteroduplex analysis using denaturing high-performance liquid chromatography to identify pyrazinamide (PZA) resistance in Mycobacterium tuberculosis isolates and simultaneously differentiate between M. tuberculosis and Mycobacterium bovis. Features that contributed to an optimal assay included the use of two different reference probes for the pncA gene targets from wild-type M. tuberculosis and wild-type M. bovis, optimization of the column temperature, increasing the starting concentration of the elution buffer, and reducing the rate of elution buffer increase (slope). A total of 69 strains were studied, including 48 wild-type M. tuberculosis strains (13 were PZA-resistant strains) and 21 M. bovis strains (8 were BCG strains). In all isolates tested, wild-type M. tuberculosis generated a single-peak pattern when mixed with the M. tuberculosis probe and a double-peak pattern with the M. bovis probe. In contrast, all M. bovis isolates generated a double-peak pattern when mixed with the M. tuberculosis probe and a single-peak pattern with the M. bovis probe. PZA-resistant mutant M. tuberculosis isolates generated characteristic patterns that were easily distinguishable from both wild-type M. tuberculosis and M. bovis isolates. Chromatographic patterns generated by the two reference probes allowed the rapid detection of PZA resistance with the simultaneous ability to distinguish between M. tuberculosis and M. bovis. This approach may allow the detection of drug resistance-associated mutations, with potential application to clinical and epidemiological aspects of tuberculosis control. 相似文献
3.
Hannan MM Desmond EP Morlock GP Mazurek GH Crawford JT 《Journal of clinical microbiology》2001,39(2):647-650
Mycobacterium bovis is naturally resistant to the antituberculosis drug pyrazinamide (PZA). To determine whether all Mycobacterium tuberculosis complex isolates demonstrating PZA monoresistance were truly M. bovis, we examined the phenotype and genotype of isolates reported as PZA monoresistant in five counties in California from January 1996 through June 1999. Isolates reported by local laboratories to be PZA monoresistant were sent to the state reference laboratory for repeat susceptibility testing using the BACTEC radiometric method and to the Centers for Disease Control and Prevention for pncA sequencing and PCR-restriction fragment length polymorphism (RFLP) analysis of the oxyR gene. Of 1,916 isolates, 14 were reported as PZA monoresistant and 11 were available for retesting. On repeat testing, 6 of the 11 isolates were identified as PZA-susceptible M. tuberculosis, 1 was identified as PZA-monoresistant M. bovis, and 1 was identified as M. bovis BCG. The three remaining isolates were identified as PZA-monoresistant M. tuberculosis. Sequencing of the pncA and oxyR genes genotypically confirmed the two M. bovis and the six susceptible M. tuberculosis species. Each of the three PZA-monoresistant M. tuberculosis isolates had different, previously unreported, pncA gene mutations: a 24-bp deletion in frame after codon 88, a base substitution at codon 104 (Ser104Cys), and a base substitution at codon 90 (Ile90Ser). This study demonstrates that PZA monoresistance is not an absolute marker of M. bovis species but may also occur in M. tuberculosis, associated with a number of different mutational events in the pncA gene. It is the first report of PZA-monoresistant M. tuberculosis in the United States. 相似文献
4.
Honl M Rentzsch R Schwieger K Carrero V Dierk O Dries S Louis H Pude F Bishop N Hille E Morlock M 《Bio-medical materials and engineering》2003,13(4):317-325
In revision surgeries of endoprostheses, the interface between implant and bone cement or bone must be loosened. Conventional tools have many disadvantages because of their size and limited range. Taking advantage of the selective and athermic cutting process, a plain water jet is already used in order to cut soft tissues. This study investigates the possibilities of both a plain and an abrasive water jet as cutting tools for revision surgery. Samples of the mid-diaphysis of human femora and bone cement (CMW3) were cut with a plain water jet (PWJ) and an abrasive water jet (AWJ) at two different jet-to-surface angles (30 degrees,90 degrees ) and at five different pressure levels (30, 40, 50, 60, 70 MPa). For a PWJ a selective pressure range was identified, where only bone cement was cut. Injecting a bio-compatible abrasive (lactose) to the jet stream resulted in significantly higher cut depths in both materials. Material removal in bone was significantly less at the smaller jet-to-surface angle for both techniques. No clear selectivity between bone and bone cement was observed for application of the AWJ. However, the material removal rate was significantly higher for bone cement than for bone at all pressure levels. The results indicate that an AWJ might be an alternative tool for cement removal. The possibility for localised cutting at interfaces could be an advantage for revision of a non-cemented prosthesis. 相似文献
5.
Our national sample of 750 randomly chosen firms with fewer than 50 employees reveals surprising findings about the traditional views of small business on health care reform. A substantial segment of the small business community is sympathetic to health care reform, including such controversial measures as mandating that all employers contribute to the coverage of their workers, limits on health care spending, and altering the tax treatment of employer contributions for health insurance. Without premium savings, fewer than half of small businesses support the concept of health insurance purchasing cooperatives. With premium savings, a majority support it. 相似文献
6.
Prof. Dr. W. Lehmann M. Rupprecht A. Rücker M. Hoffmann M. Morlock K. Püschel J.M. Rueger 《Trauma und Berufskrankheit》2012,14(3):190-195
The treatment of interprosthetic fractures is challenging and the incidence is increasing as a result of increasing patient longevity and rising arthroplasty rates. Interprosthetic fractures occur between arthroplasty stems or any intramedullary implant that has been implanted for fracture fixation. Management of these fractures is a complex undertaking. The majority of fractures are localized at the femoral supracondylar level after knee resurfacing arthroplasty. The fixation status of the arthroplasty component determines the management strategies. As a result of clinical and biomechanical studies, loosening of the implant usually requires revision arthroplasty, whereas minimally invasive reduction and locked internal fixation is the treatment of choice for stable implants. Minimally invasive surgery is necessary to not further compromise local perfusion. As locked plating provides superior biomechanical stability, the use of cerclage cables should be carefully evaluated. Complex fracture configurations, inferior bone stock or an intramedullary canal that is already occupied by support structures might obviate the implantation of long revision stems and might require a more extensive approach (e.g., total femoral arthroplasty). 相似文献
7.
8.
9.
Jan Philipp Kolb Rebecca A. Kueny Klaus Püschel Andreas Boger Johannes M. Rueger Michael M. Morlock Gerd Huber Wolfgang Lehmann 《European spine journal》2013,22(7):1650-1656
Purpose
Normal progression of osteoporosis or the rigid reinforcement of the fractured vertebral body with polymethyl methacrylate (PMMA) cement is being discussed as a cause for adjacent-level fractures after vertebroplasty. The purpose of this study was to investigate whether augmentation with low stiffness cement can decrease the risk of adjacent-level fractures in low-quality bone.Methods
Eighteen female osteoporotic lumbar specimens (L1–L5) were harvested and divided into three groups according to bone mineral density: (I) native; (II) PMMA; (III) modified PMMA (lower stiffness). For the PMMA and modified PMMA groups, a compression fracture was first mechanically induced in L3, and then the fracture received vertebroplasty treatment. The cement stiffness reduction of the modified PMMA group was achieved via an addition of 8 mL of serum to the typical PMMA base. All specimens were exposed to cyclic loading (4 Hz) and a stepwise increasing applied peak force. Cement stiffness was tested according to ISO 5833.Results
A 51 % decrease in cement stiffness was achieved in the modified PMMA group (954 ± 141 vs. 1,937 ± 478 MPa, p < 0.001). Fatigue fracture force (the force level during cyclic loading at which the deformation experienced a sudden increase; FFF) was significantly affected by bone quality (r 2 = 0.39, p = 0.006) and by the initial fracture force (the force necessary to create the initial fracture in L3 prior to augmentation; r 2 = 0.82, p < 0.001). Using initial fracture force as a covariate, the FFF of the modified PMMA group (1,764 ± 49 N) was significantly higher than in the PMMA group (1,544 ± 55 N; p = 0.03).Conclusions
A possible method to reduce adjacent-level fractures after vertebroplasty in patients with reduced bone quality could be the use of a lower modulus cement. Therefore, mixing cement with biocompatible fluids could prove useful to tailor cement properties in the operating theater. 相似文献10.
Florian Fensky Rebecca A. Kueny Kay Sellenschloh Klaus Püschel Michael M. Morlock Johannes M. Rueger Wolfgang Lehmann Gerd Huber Nils Hansen-Algenstaedt 《European spine journal》2014,23(4):724-731