全文获取类型
收费全文 | 169篇 |
免费 | 6篇 |
国内免费 | 12篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 13篇 |
2013年 | 15篇 |
2012年 | 7篇 |
2011年 | 14篇 |
2010年 | 10篇 |
2009年 | 8篇 |
2008年 | 5篇 |
2007年 | 8篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有187条查询结果,搜索用时 15 毫秒
181.
ABSTRACT
Here, we describe a procedure to fluorescently contrast the nuclear boundary using the lipophilic carbocyanine dye DiI in cultured human cells. Our procedure is simple and is applicable to detect nuclear boundary defects, which may be relevant to studies on nuclear envelope dynamics, micronuclei formation and cancer biology. 相似文献
182.
ABSTRACT IES-LA is a short Internal Eliminated Sequence interrupting LA-MSC, a protein-coding gene of the 81 locus of Oxytricha fallax and O. trifallax. IES-LA is precisely excised from the gene during development of the macronucleus. The internal eliminated sequence is bounded by CAAT… AATG, and thereby resembles a TBE1 transposon internal eliminated sequence insertion that is grossly shortened (4.1 kbp to 52-64 bp), consistent with the hypothesis that short IESs are degenerated ancient transposons. The pattern of sequence conservation between five alleles of IES-LA shows that it differs from previously characterized classes of ciliate short IESs: while many short IESs have conserved ends and diverged centers, IES-LA is more conserved in its center and its ends are diverged. This implies a excision mechanism for IES-LA that is distinct from those for other known Oxytricha IESs. 相似文献
183.
Fábio Vieira dos Santos Vanessa Jaqueline da Silva Vieira dos Santos Maria José Farias Suzana de Fátima Paccola Mesquita Maria Aparecida Maciel Angelo da Cunha Pinto Ilce Mara de Syllos Cólus 《Biologia》2008,63(3):327-331
Croton cajucara Benth. (‘sacaca’) is a tree of the Euphorbiaceae family, native to the Amazon region in northern Brazil, where it is widely used in the popular
treatment of various diseases. Its active principle, the terpenoid trans-dehydrocrotonin, has been credited with a variety of medical properties, including antiulcer, antiinflammatory, antitumor,
antimutagenic and hypoglycemic activity. In this investigation, possible mutagenic and antimutagenic effects were evaluated
in treatments using methanol extract of this plant on Swiss Albino mice by examining their peripheral blood cells for micronuclei.
In these tests, the material obtained by methanol extraction of C. cajucara tree bark was administered to the mice by gavage. None of the doses evaluated in this study presented mutagenicity. Analysis
of the results obtained from studies evaluating antimutagenicity revealed protection against the chemotherapeutic agent cyclophosphamide
for the two highest doses used. 相似文献
184.
A. Abou-Eisha A. Creus R. Marcos 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》1999,440(2):208
The antimicrobial drug, trimethoprim, was evaluated for genotoxicity in human peripheral blood lymphocyte cultures set-up from two healthy donors. Sister-chromatid exchanges (SCE) and micronuclei (MN) were scored as genetic endpoints. The treatment was done using different trimethoprim concentrations ranging from 1 to 100 μg/ml. From our results, we can conclude that this drug is able to induce both cytotoxic and moderate genotoxic effects, as revealed by the increases seen in SCE and MN frequencies in cultures from the two donors and, at least, at one of the concentrations tested. 相似文献
185.
Carlos F. Campos Boscolli B. Pereira Edimar O. de Campos-Junior Eduardo F. Sousa Henrique N. Souto Sandra Morelli 《Genetics and molecular biology》2015,38(4):507-512
Pollutants have adverse effects on human health and on other organisms that inhabit
or use water resources. The aim of the present study was to assess the environmental
quality of three watercourses in Monte Carmelo, MG, Brazil, using the micronucleus
test on Tradescantia. For each treatment, 15 plants were exposed to
water samples for 24 h. The control group was exposed to formaldehyde (0.2%) and the
negative control to Hoagland solution. Subsequently the plants were placed in
Hoagland solution for 24 h to recover. Cells were stained with 2% acetic carmine and
examined by light microscopy. Three hundred tetrads were analyzed per slide. The
frequency of genotoxic alterations was expressed as the number of micronuclei per 100
tetrads, and the groups were compared by ANOVA. At all sample sites for each
watercourse significant genotoxicity indices were observed. The results suggest that
in the Mumbuca creek, the current situation of effluent discharge should be
reconsidered by the municipal environmental authorities. The increase in micronucleus
frequency denoted for water samples of the Mumbuca creek, Lambari river and Perdizes
river emphasizes the need to adopt environmental vigilance strategies, such as
biological monitoring. 相似文献
186.
《Biotechnic & histochemistry》2013,88(4):187-188
A study has been made on the possibility of replacing leucofuchsin by colored basic fuchsin for the histochemical demonstration of aldehydes. Several tissues from mammals and various pertinent fixatives were used. Aldehydes were freed from carbohydrates by oxidation and from thymonucleic acid by hydrolysis.It was found that the colored form and not necessarily the leucoform of basic fuchsin can be used histochemically in demonstrating aldehydes. The technic used is as follows: (1) Treat with 1.0–0.5% H5IO6 (or in 1% KIO4 in M/1 H2SO4) for 5 to 10 min. and wash thoroughly. For thymonucleic acid hydrolize with N HCl 5 min. at room temperature, 10 min. at 60°C. and 5 min. at room temperature. (2) Stain for 2–3 min. with 0.05% basic fuchsin in 5% ethanol, 3% phenol. (3). Transfer immediately to 1 or 2 changes of 1% sodium bisulphite or potassium metabisulphite in 0.1–0.2 N H2SO4 for a total of 5 min. (4) Rinse with water and treat with M H2SO4 in 95% ethanol for 3–5 min. 6. Wash thoroughly in water and dehydrate, clear, and mount. For glycogen and mucin the following counterstaining solution is recommended: orange G, 0.25 g.; light green SFY, 0.10 g.; phosphotungstic acid 0.50 g.; 50% ethanol, 100 ml.; glacial acetic acid, 0.25 ml. 相似文献
187.
Synopsis.
The DNA of the macro- and the micronucleus of Tetrahymena thermophila has been compared by various biochemical methods. It became evident from their thermal denaturation temperatures and buoyant densities that the 2 DNAs were very similar in overall composition. Small differences were detected when the sequence complexities of these DNAs were compared by DNA renaturation studies. The studies suggested that ˜ 10% of the micronuclear genome was lost or underrepresented in the macronucleus. Comparison of individual gene levels revealed further differences. By using the technic of gene cloning a micronuclear sequence was isolated which hybridized only with micronuclear, but not with macronuclear DNA. These results indicated the occurrence of elimination or underreplication of this sequence in the macronucleus. Gene amplification was also shown to occur. In the micronucleus only a single copy of rDNA was found integrated into the chromosome. During macro-nuclear development, amplification was observed to occur, and the amount of rDNA to increase, until there were ˜ 200 copies per haploid genome in the mature macronucleus. all of them extrachromosomal and palindromic. The 3rd case of alteration involved a simple repeated sequence, (CCCCAA)n, present in the termini of rDNA and also in many other locations of the genome. Restriction endonuclease digestion studies revealed drastic differences in the organization of the repeats between macro-and micronucleus. These differences may be interpreted as the results of chromosome fragmentation which occurs at every cluster of the repeats during macronuclear development. The relationship between this event and gene amplification and elimination is discussed. 相似文献
The DNA of the macro- and the micronucleus of Tetrahymena thermophila has been compared by various biochemical methods. It became evident from their thermal denaturation temperatures and buoyant densities that the 2 DNAs were very similar in overall composition. Small differences were detected when the sequence complexities of these DNAs were compared by DNA renaturation studies. The studies suggested that ˜ 10% of the micronuclear genome was lost or underrepresented in the macronucleus. Comparison of individual gene levels revealed further differences. By using the technic of gene cloning a micronuclear sequence was isolated which hybridized only with micronuclear, but not with macronuclear DNA. These results indicated the occurrence of elimination or underreplication of this sequence in the macronucleus. Gene amplification was also shown to occur. In the micronucleus only a single copy of rDNA was found integrated into the chromosome. During macro-nuclear development, amplification was observed to occur, and the amount of rDNA to increase, until there were ˜ 200 copies per haploid genome in the mature macronucleus. all of them extrachromosomal and palindromic. The 3rd case of alteration involved a simple repeated sequence, (CCCCAA)n, present in the termini of rDNA and also in many other locations of the genome. Restriction endonuclease digestion studies revealed drastic differences in the organization of the repeats between macro-and micronucleus. These differences may be interpreted as the results of chromosome fragmentation which occurs at every cluster of the repeats during macronuclear development. The relationship between this event and gene amplification and elimination is discussed. 相似文献