全文获取类型
收费全文 | 125篇 |
免费 | 6篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 9篇 |
2014年 | 8篇 |
2013年 | 8篇 |
2012年 | 4篇 |
2011年 | 10篇 |
2010年 | 13篇 |
2009年 | 11篇 |
2008年 | 10篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1989年 | 3篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1978年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有131条查询结果,搜索用时 31 毫秒
1.
Comparison of kinetics of active tetracycline uptake and active tetracycline efflux in sensitive and plasmid RP4-containing Pseudomonas putida. 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《Journal of bacteriology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Membrane vesicles prepared from tetracycline-sensitive cells of Pseudomonas putida took up tetracycline by an active transport system with an apparent Km of 2.5 mM and a Vmax of 50 nmol min-1 mg protein-1. In contrast, resistance determinant RP4-containing P. putida had an active high-affinity efflux system for tetracycline with a Km of 2.0 to 3.54 microM and a Vmax of 0.15 nmol min-1 mg protein-1. Thus, the efflux system of tetracycline-resistant P. putida(RP4) had an average of 1,000-fold greater affinity for tetracycline than the influx system of tetracycline-sensitive cells. From these results, it is clear that a major mechanism of tetracycline resistance in RP4-containing P. putida is an active tetracycline efflux mechanism. There was also evidence for a second tetracycline efflux system with low affinity for tetracycline n P. putida(RP4). This efflux system had a Km of 0.25 mM and a Vmax of 1.45 nmol min-1 protein-1. Whether this low-affinity efflux system was also present in tetracycline-sensitive P. putida could not be discerned from these experiments. 相似文献
2.
Nicky HGM Peters Inne HM Borel Rinkes Willem PTM Mali Maurice AAJ van den Bosch Remmert K Storm Peter W Plaisier Erwin de Boer Adriaan J van Overbeeke Petra HM Peeters 《Trials》2007,8(1):1-7
Background
In orthodontic treatment, anchorage control is a fundamental aspect. Usually conventional mechanism for orthodontic anchorage control can be either extraoral or intraoral that is headgear or intermaxillary elastics. Their use are combined with various side effects such as tipping of occlusal plane or undesirable movements of teeth. Especially in cases, where key-teeth are missing, conventional anchorage defined as tooth-borne anchorage will meet limitations. Therefore, the use of endosseous implants for anchorage purposes are increasingly used to achieve positional stability and maximum anchorage.Methods/Design
The intended study is designed as a prospective, multicenter randomized controlled trial (RCT), comparing and contrasting the effect of early loading of palatal implant therapy versus implant loading after 12 weeks post implantation using the new ortho-implant type II anchor system device (Orthosystem Straumann, Basel, Switzerland). 124 participants, mainly adult males or females, whose diagnoses require temporary stationary implant-based anchorage treatment will be randomized 1:1 to one of two treatment groups: group 1 will receive a loading of implant standard therapy after a healing period of 12 week (gold standard), whereas group 2 will receive an early loading of orthodontic implants within 1 week after implant insertion. Participants will be at least followed for 12 months after implant placement. The primary endpoint is to investigate the behavior of early loaded palatal implants in order to find out if shorter healing periods might be justified to accelerate active orthodontic treatment. Secondary outcomes will focus e.g. on achievement of orthodontic treatment goals and quantity of direct implant-bone interface of removed bone specimens. As tertiary objective, a histologic and microtomography evaluation of all retrieved implants will be performed to obtain data on the performance of the SLA surface in human bone evaluation of all retrieved implants. Additionally, resonance frequency analysis (RFA, Osstell? mentor) will be used at different times for clinically monitoring the implant stability and for histological comparison in order to measure the reliability of the resonance frequency measuring device.Trial registration
Current Controlled Trials ISRCTN97142521. 相似文献3.
Embryonic stem (ES) cell lines represent a population of undifferentiated pluripotent cells capable of multilineage differentiation in vitro. Although very useful for studying developmental processes, human ES cell lines have also been suggested as a potential and unlimited source for cellular transplantation and the treatment of human disease. The proteomic basis of embryonic stemness (pluripotentiality and multilineage differentiation) and the transitions that lead to specific cell lineages however, remain to be defined. As an important first step in defining these processes, we have performed a proteomic analysis of undifferentiated mouse R1 ES cell lines using pH 3-10, 4-7 and 6-11 two-dimensional electrophoresis gels, matrix-assisted laser desorption/ionization and tandem mass spectrometry. Of the 700 gel spots analyzed, 241 distinct protein species were identified corresponding to 218 unique proteins, with a significant proportion functionally related to protein expression. 相似文献
4.
Vacuolar-type H+-translocating ATPases (V-ATPases or V-pumps) are complex proteins containing multiple subunits and are organized into two functional domains: a peripheral catalytic sector V1 and a membranous proton channel V0. The functional coupling of ATP hydrolysis activity to proton transport in V-pumps requires a regulatory component known as subunit H (SFD) as has been shown both in vivo and in vitro (Ho, M. N., Hirata, R., Umemoto, N., Ohya, Y., Takatsuki, A., Stevens, T. H., and Anraku, Y. (1993) J. Biol. Chem. 268, 18286-18292; Xie, X. S., Crider, B. P., Ma, Y. M., and Stone, D. K. (1994) J. Biol. Chem. 269, 25809-25815). Ca2+ is thought to uncouple V-pumps because it is found to support ATP hydrolysis but not proton transport, while Mg2+ supports both activities. The direct effect of phospholipids on the coupling of V-ATPases has not been reported, likely due to the fact that phospholipids are constituents of biological membranes. We now report that Ca2+-induced uncoupling of the bovine brain V-ATPase can be reversed by imposition of a favorable membrane potential. Furthermore we report a simple "membrane-free" assay system using the V0 proton channel-specific inhibitor bafilomycin as a probe to detect the coupling of V-ATPase under certain conditions. With this system, we have characterized the functional effect of subunit H, divalent cations, and phospholipids on bovine brain V-ATPase and have found that each of these three factors plays a critical role in the functional coupling of the V-pump. 相似文献
5.
Jolanda?HM?van Bilsen Josée?PA?Wagenaar-Hilbers Maarten?JF?van der Cammen Mariska?EA?van Dijk Willem?van Eden Marca?HM?WaubenEmail author 《Arthritis research & therapy》2002,4(4):R2
We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental
arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the
course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration
of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the
MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP
peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development
of such therapies. 相似文献
6.
7.
U.S. women of childbearing age who are at possible increased risk of a neural tube defect‐affected pregnancy due to suboptimal red blood cell folate concentrations,National Health and Nutrition Examination Survey 2007 to 2012
下载免费PDF全文
![点击此处可从《Birth defects research. Part A, Clinical and molecular teratology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
8.
9.
Cecilie?M?MejdellEmail author Grete?HM?J?rgensen Therese?Rehn Kjersti?Fremstad Linda?Keeling Knut?E?B?e 《Acta veterinaria Scandinavica》2010,52(1):68
Background
The risk of injuries is of major concern when keeping horses in groups and there is a need for a system to record external injuries in a standardised and simple way. The objective of this study, therefore, was to develop and validate a system for injury recording in horses and to test its reliability and feasibility under field conditions.Methods
Injuries were classified into five categories according to severity. The scoring system was tested for intra- and inter-observer agreement as well as agreement with a 'golden standard' (diagnosis established by a veterinarian). The scoring was done by 43 agricultural students who classified 40 photographs presented to them twice in a random order, 10 days apart. Attribute agreement analysis was performed using Kendall's coefficient of concordance (Kendall's W), Kendall's correlation coefficient (Kendall's τ) and Fleiss' kappa. The system was also tested on a sample of 100 horses kept in groups where injury location was recorded as well.Results
Intra-observer agreement showed Kendall's W ranging from 0.94 to 0.99 and 86% of observers had kappa values above 0.66 (substantial agreement). Inter-observer agreement had an overall Kendall's W of 0.91 and the mean kappa value was 0.59 (moderate). Agreement for all observers versus the 'golden standard' had Kendall's τ of 0.88 and the mean kappa value was 0.66 (substantial). The system was easy to use for trained persons under field conditions. Injuries of the more serious categories were not found in the field trial.Conclusion
The proposed injury scoring system is easy to learn and use also for people without a veterinary education, it shows high reliability, and it is clinically useful. The injury scoring system could be a valuable tool in future clinical and epidemiological studies.10.