全文获取类型
收费全文 | 136篇 |
免费 | 18篇 |
出版年
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 10篇 |
2013年 | 8篇 |
2012年 | 8篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2008年 | 9篇 |
2007年 | 8篇 |
2006年 | 12篇 |
2005年 | 7篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 8篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有154条查询结果,搜索用时 125 毫秒
1.
This paper deals with the behavioral pattern of neighbor relations and their relationships to the subjective attitudes and expectations of the residents. The sample was 318 middle-class women living in eight-to 20-story buildings. The findings indicate that respondents so desiring were able to develop active social ties with their neighbors. Moreover, they interacted with neighbors despite the fact that the majority had opportunities for alternative social relations. The distinction between localized and nonlocalized high-rise residents does not seem meaningful in this case. Actual social ties with neighbors were related to norms and expectations regarding neighbor relations. Despite active neighboring, respondents did not have difficulties obtaining privacy. 相似文献
2.
Summary The anticancer drugs adriamycin (ADR) and actinomycin D (AMD) were tested for their effect on the oxidative burst (OB) of mouse peritoneal macrophages (MPM) and on the killing of tumor cells by OB-stimulated MPM. The oxidative burst of MPM determined by hydrogen peroxide (H2O2) production was severely impaired by ADR (10 g/ml) and AMD (40 g/ml) after a 1 h treatment and by lower concentrations of the drugs following a 24 h treatment. The toxicity of the drugs against MPM was comparable to their effect on EL4 cells. Pretreatment of EL4 and TLX-9 tumor cells with sublethal amounts of ADR for 4 h rendered the cells sensitive to the cytotoxic effect of OB-stimulated MPM which were otherwise unable to kill these cells. It seems that anticancer drugs and OB-stimulated macrophages can cooperate in the destruction of tumor cells in vitro. 相似文献
3.
Nora Vaisman Andrey Tsouladze Kenneth Robzyk Sigal Ben-Yehuda Martin Kupiec Yona Kassir 《Molecular genetics and genomics : MGG》1995,247(2):123-136
Successful progression through the cell cycle requires the coupling of mitotic spindle formation to DNA replication. In this report we present evidence suggesting that, inSaccharomyces cerevisiae, theCDC40 gene product is required to regulate both DNA replication and mitotic spindle formation. The deduced amino acid sequence ofCDC40 (455 amino acids) contains four copies of a β-transducin-like repeat. Cdc40p is essential only at elevated temperatures, as a complete deletion or a truncated protein (deletion of the C-terminal 217 amino acids in thecdc40-1 allele) results in normal vegetative growth at 23°C, and cell cycle arrest at 36°C. In the mitotic cell cycle Cdc40p is apparently required for at least two steps: (1) for entry into S phase (neither DNA synthesis, nor mitotic spindle formation occurs at 36°C and (2) for completion of S-phase (cdc40::LEU2 cells cannot complete the cell cycle when returned to the permissive temperature in the presence of hydroxyurea). The role of Cdc40p as a regulatory protein linking DNA synthesis, spindle assembly/maintenance, and maturation promoting factor (MPF) activity is discussed. 相似文献
4.
Vered Yesodi Shamay Izhar David Gidoni Yona Tabib Nurit Firon 《Molecular genetics and genomics : MGG》1995,248(5):540-546
In petunia, a mitochondrial (mt) locus,S-Pcf, has been found to be strongly associated with cytoplasmic male sterility (CMS). TheS-Pcf locus consists of three open reading frames (ORF) that are co-transcribed. The first ORF,Pcf, contains parts of theatp9 andcoxII genes and an unidentified reading frame,urf-s. The second and third ORFs contain NADH dehydrogenase subunit 3 (nad3) and ribosomal protein S12 (rps12) sequences, respectively. Thenad3 andrps12 sequences included in theS-Pcf locus are identical to the corresponding sequences on the mt genome of fertile petunia. In both CMS and fertile petunia, only a single copy ofnad3 andrps12 has been detected on the physical map of the main mt genome. The origin of theurf-s sequence and the molecular events leading to the formation of the chimericS-Pcf locus are not known. This paper presents evidence indicating that two different mt sequences, related tourf-s and found in fertile petunia lines (orf-h and Rf-1), might have been involved in the molecular evolution of theS-Pcf locus. Southern analysis of mtDNA derived from both fertile and sterile petunia plants suggests that one of theseurf-s related sequences (showing 100% homology tourf-s and termedorf-h) is located on a sublimon. An additional, low-homologyurf-s related sequence (Rf-1) is shown to be located on the main mt genome 5′ to thenad3 gene. It is, thus, suggested that the sequence of events leading to the generation of theS-Pcf locus might have involved introduction of theorf-h sequence, via homologous recombination, into the main mt genome 5′ tonad3 at the region where the Rf-1 sequence is located. 相似文献
5.
Vered Yesodi Shamay Izhar David Gidoni Yona Tabib Nurit Firon 《Molecular & general genetics : MGG》1995,248(5):540-546
In petunia, a mitochondrial (mt) locus,S-Pcf, has been found to be strongly associated with cytoplasmic male sterility (CMS). TheS-Pcf locus consists of three open reading frames (ORF) that are co-transcribed. The first ORF,Pcf, contains parts of theatp9 andcoxII genes and an unidentified reading frame,urf-s. The second and third ORFs contain NADH dehydrogenase subunit 3 (nad3) and ribosomal protein S12 (rps12) sequences, respectively. Thenad3 andrps12 sequences included in theS-Pcf locus are identical to the corresponding sequences on the mt genome of fertile petunia. In both CMS and fertile petunia,
only a single copy ofnad3 andrps12 has been detected on the physical map of the main mt genome. The origin of theurf-s sequence and the molecular events leading to the formation of the chimericS-Pcf locus are not known. This paper presents evidence indicating that two different mt sequences, related tourf-s and found in fertile petunia lines (orf-h and Rf-1), might have been involved in the molecular evolution of theS-Pcf locus. Southern analysis of mtDNA derived from both fertile and sterile petunia plants suggests that one of theseurf-s related sequences (showing 100% homology tourf-s and termedorf-h) is located on a sublimon. An additional, low-homologyurf-s related sequence (Rf-1) is shown to be located on the main mt genome 5′ to thenad3 gene. It is, thus, suggested that the sequence of events leading to the generation of theS-Pcf locus might have involved introduction of theorf-h sequence, via homologous recombination, into the main mt genome 5′ tonad3 at the region where the Rf-1 sequence is located.
Contribution [No. 1581-E (1995 series)] from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
50 250 相似文献
6.
7.
A dominant mutation (SAD) bypassing the requirement for the a mating type locus in yeast sporulation
Summary
SAD (suppressor of a deficiencies) is a mutation that allows -mater diploids such as / or a1-/ strains to sporulate. This mutation is unstable and reverts to wildtype (sad
+) even in strains homozygous for SAD. SAD is dominant to sad
+: / and a1-/ sad
1/SAD diploids are sporulation-proficient. SAD is located on chromosome III, 40 cM distal to the mating type locus, between THR4 and HMR
a. The ability of SAD to support sporulation requires the presence of an mating type locus with an active 2 function. Possible models for the action of SAD are (1) SAD bypasses the need for a1 function in sporulation, and (2) SAD provides a1 function to MAT
a1- mutants by supplying a1 function itself, for example, by allowing expression of a silent copy of MAT
a. 相似文献
8.
Human fibroblast and leukocyte interferons were found to suppress lymphocyte mitogenesis induced by optimal doses of phytohemagglutinin and concanavalin A. In certain situations (low doses of mitogen and/or low doses of interferon), however, interferon significantly enhanced mitogenesis. In experiments using varying concentrations of interferon, dose-response curves with different slopes were obtained for fibroblast and leukocyte interferons. The effect of interferon was apparently exerted during early stages of the lymphocyte cell cycle. There was no inhibitory effect of interferon if the lymphocytes were washed with medium before being exposed to mitogen. Interferon increased the binding of radiolabeled mitogens to cells. The results suggest that the immunological effects of interferon are consequences of actions on lymphoid cells. Fibroblast and leukocyte interferons seem to have different modes of action, or to bind differently to target cells. Possible mechanisms for the suppressive and enhancing effects of interferons on lymphoid cells are discussed. 相似文献
9.
A supposed sporulation-deficient mutation of Saccharomyces cerevisiae is found to affect mating in haploids and in diploids, and to be inseparable from the mating-type locus by recombination. The mutation is regarded as a defective a allele and is designated a*. This is confirmed by its dominance relations in diploids, triploids, and tetraploids. Tetrad analysis of tetraploids and of their sporulating diploid progeny suggests the existence of an additional locus, RME, which regulates sporulation in yeast strains that can mate. Thus the recessive homozygous constitution rme/rme enables the diploids a*/α, a/a*, and α/α to go through meiosis. Haploids carrying rme show apparent premeiotic DNA replication in sporulation conditions. This new regulatory locus is linked to the centromere of the mating-type chromosome, and its two alleles, rme and RME, are found among standard laboratory strains. 相似文献
10.
Galina Feinberg-Gorenshtein Avital Guedj Keren Shichrur Marta Jeison Drorit Luria Yona Kodman Shifra Ash Meora Feinmesser Liat Edry Noam Shomron Abraham Weizman Isaac Yaniv Smadar Avigad 《PloS one》2013,8(11)
Neuroblastoma (NB) arises from the embryonic neural crest and is the most common extracranial solid tumor in children under 5 years of age. Reduced expression of Dicer1 has recently been shown to be in correlation with poor prognosis in NB patients. This study aimed to investigate the mechanisms that could lead to the down-regulation of Dicer1 in neuroblastoma. We used computational prediction to identify potential miRs down-regulating Dicer1 in neuroblastoma. One of the miRs that were predicted to target Dicer1 was miR-192. We measured the levels of miR-192 in 43 primary tumors using real time PCR. Following the silencing of miR-192, the levels of dicer1 cell viability, cell proliferation and migration capability were analyzed. Multivariate analysis identified miR-192 as an independent prognostic marker for relapse in neuroblastoma patients (p=0.04). We were able to show through a dual luciferase assay and side-directed mutational analysis that miR-192 directly binds the 3'' UTR of Dicer1 on positions 1232-1238 and 2282-2288. An increase in cell viability, proliferation and migration rates were evident in NB cells transfected with miR-192-mimic. Yet, there was a significant decrease in proliferation when NB cells were transfected with an miR-192-inhibitor We suggest that miR-192 might be a key player in NB by regulating Dicer1 expression. 相似文献