全文获取类型
收费全文 | 89篇 |
免费 | 29篇 |
学科分类
医药卫生 | 118篇 |
出版年
2024年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2013年 | 3篇 |
2012年 | 8篇 |
2011年 | 3篇 |
2010年 | 1篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 10篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 3篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1966年 | 2篇 |
排序方式: 共有118条查询结果,搜索用时 15 毫秒
1.
K K Valu T A Gourdie T J Boritzki G L Gravatt B C Baguley W R Wilson L P Wakelin P D Woodgate W A Denny 《Journal of medicinal chemistry》1990,33(11):3014-3019
Four series of acridine-linked aniline mustards have been prepared and evaluated for in vitro cytotoxicity, in vivo antitumor activity, and DNA cross-linking ability. The anilines were attached to the DNA-intercalating acridine chromophores by link groups (-O-, -CH2-, -S-, and -SO2-) of widely varying electronic properties, providing four series of widely differing mustard reactivity where the alkyl chain linking the acridine and mustard moieties was varied from two to five carbons. Relationships were sought between chain length and biological properties. Within each series, increasing the chain length did not alter the reactivity of the alkylating moiety but did appear to position it differently on the DNA, since cross-linking ability (measured by agarose gel assay) altered with chain length, being maximal with the C4 analogue. The in vivo antitumor activities of the compounds depended to some extent on the reactivity of the mustard, with the least reactive SO2 compounds being inactive. However, DNA-targeting did appear to allow the use of less reactive mustards, since the S-linked acridine mustards showed significant activity whereas the parent S-mustard did not. Within each active series, the most active compound was the C4 homologue, suggesting some relationship between activity and extent of DNA alkylation. 相似文献
2.
Activity of the purified mutagenesis proteins UmuC, UmuD'', and RecA in replicative bypass of an abasic DNA lesion by DNA polymerase III. 总被引:4,自引:3,他引:4 下载免费PDF全文
M Rajagopalan C Lu R Woodgate M O''''Donnell M F Goodman H Echols 《Proceedings of the National Academy of Sciences of the United States of America》1992,89(22):10777-10781
The introduction of a replication-inhibiting lesion into the DNA of Escherichia coli generates the induced, multigene SOS response. One component of the SOS response is a marked increase in mutation rate, dependent on RecA protein and the induced mutagenesis proteins UmuC and UmuD. A variety of previous indirect approaches have indicated that SOS mutagenesis results from replicative bypass of the DNA lesion by DNA polymerase III (pol III) holoenzyme in a reaction mediated by RecA, UmuC, and a processed form of UmuD termed UmuD'. To study the biochemistry of SOS mutagenesis, we have reconstituted replicative bypass with a defined in vitro system containing purified protein and a DNA substrate with a single abasic DNA lesion. The replicative bypass reaction requires pol III, UmuC, UmuD', and RecA. The nonprocessed UmuD protein does not replace UmuD' but inhibits the bypass activity of UmuD', perhaps by sequestering UmuD' in a heterodimer. Our experiments demonstrate directly that the UmuC-UmuD' complex and RecA act to rescue an otherwise stalled pol III holoenzyme at a replication-blocking DNA lesion. 相似文献
3.
Woodgate Samuel Morgan-Jones Philippa Clinch Susanne Drew Cheney Playle Rebecca Bennasar Mohamed Hicks Yulia Holt Catherine Bachoud-Lévi Anne-Catherine Massart Renaud Craufurd David Kirby Nigel Hamana Katy Schubert Robin Reilmann Ralf Rosser Anne Busse Monica 《Journal of neurology》2021,268(7):2550-2559
Journal of Neurology - The Clinch Token Transfer Test (C3t) is a bi-manual coin transfer task that incorporates cognitive tasks to add complexity. This study explored the concurrent and convergent... 相似文献
4.
Efficient translesion replication in the absence of Escherichia coli Umu proteins and 3′–5′ exonuclease proofreading function 下载免费PDF全文
Dominique Vandewiele Angela Borden Paul I. OGrady Roger Woodgate Christopher W. Lawrence 《Proceedings of the National Academy of Sciences of the United States of America》1998,95(26):15519-15524
Translesion replication (TR) past a cyclobutane pyrimidine dimer in Escherichia coli normally requires the UmuD′2C complex, RecA protein, and DNA polymerase III holoenzyme (pol III). However, we find that efficient TR can occur in the absence of the Umu proteins if the 3′–5′ exonuclease proofreading activity of the pol III -subunit also is disabled. TR was measured in isogenic uvrA6 ΔumuDC strains carrying the dominant negative dnaQ allele, mutD5, or ΔdnaQ spq-2 mutations by transfecting them with single-stranded M13-based vectors containing a specifically located cis-syn T–T dimer. As expected, little TR was observed in the ΔumuDC dnaQ+ strain. Surprisingly, 26% TR occurred in UV-irradiated ΔumuDC mutD5 cells, one-half the frequency found in a uvrA6 umuDC+mutD5 strain. lexA3 (Ind−) derivatives of the strains showed that this TR was contingent on two inducible functions, one LexA-dependent, responsible for ≈70% of the TR, and another LexA-independent, responsible for the remaining ≈30%. Curiously, the ΔumuDC ΔdnaQ spq-2 strain exhibited only the LexA-independent level of TR. The cause of this result appears to be the spq-2 allele, a dnaE mutation required for viability in ΔdnaQ strains, since introduction of spq-2 into the ΔumuDC mutD5 strain also reduces the frequency of TR to the LexA-independent level. The molecular mechanism responsible for the LexA-independent TR is unknown but may be related to the UVM phenomenon [Palejwala, V. A., Wang, G. E., Murphy, H. S. & Humayun, M. Z. (1995) J. Bacteriol. 177, 6041–6048]. LexA-dependent TR does not result from the induction of pol II, since TR in the ΔumuDC mutD5 strain is unchanged by introduction of a ΔpolB mutation. 相似文献
5.
6.
Despite the appeal of discovering the different strengths of various research methods, mixed methods research remains elusive in pediatric oncology nursing research. If pediatric oncology nurses are to succeed in mixing quantitative and qualitative methods, they need practical guidelines for managing the complex data and analyses of mixed methods research. This article discusses mixed methods terminology, designs, and key design features. Specific areas addressed include the myths about mixed methods research, types of mixed method research designs, steps involved in developing a mixed method research study, and the benefits and challenges of using mixed methods designs in pediatric oncology research. Examples of recent research studies that have combined quantitative and qualitative research methods are provided. The term mixed methods research is used throughout this article to reflect the use of both quantitative and qualitative methods within one study rather than the use of these methods in separate studies concerning the same research problem. 相似文献
7.
8.
9.
Woodgate RL 《Cancer nursing》2005,28(1):8-15
Adolescents with cancer face many challenges that may impact negatively their psychological well-being. In evaluating the psychosocial functioning of adolescents with cancer, research suggests that an altered self-image may emerge in those who have difficulty adjusting. However, little is known about adolescents' perceptions of how cancer affects their sense of self. Part of a larger study, this article addresses findings specific to understanding the impact that cancer and its symptoms had on adolescents' sense of self. To help discover meaningful interpretations of their experiences, a longitudinal, qualitative study was conducted. Data collection methods included open-ended, individual and focus group interviews and participant observation. The constant comparative method of data analysis yielded theoretical categories that were supported by the adolescents' narratives. Findings revealed that adolescents experienced changes in their lived bodies because of the symptoms and this, in turn, impacted their sense of self and way of being in the world. Six ways of being in the world were identified: life as a klutz; life as a prisoner; life as an invalid; life as an alien; life as a zombie; and life as a kid. In helping adolescents deal with the changes, it was important to family and friends to respond to them like they were the same person, but also to treat them special at times. Although adolescents spoke to the significance that cancer had on their lives, they described themselves as "still being pretty much the same person." 相似文献
10.