全文获取类型
收费全文 | 255篇 |
免费 | 8篇 |
专业分类
263篇 |
出版年
2020年 | 1篇 |
2013年 | 7篇 |
2012年 | 4篇 |
2011年 | 3篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 3篇 |
1989年 | 7篇 |
1988年 | 20篇 |
1987年 | 12篇 |
1986年 | 18篇 |
1985年 | 13篇 |
1984年 | 5篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 6篇 |
1976年 | 11篇 |
1975年 | 11篇 |
1974年 | 9篇 |
1973年 | 13篇 |
1972年 | 9篇 |
1971年 | 3篇 |
1970年 | 1篇 |
1969年 | 4篇 |
1968年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有263条查询结果,搜索用时 0 毫秒
1.
The analyses of R- and C-banding patterns of chromosomes of Arvicanthis niloticus originating from two different localities (Egypt and Central African Republic) revealed karyotypic differences caused by one pericentric inversion and three translocations, one being reciprocal and the others Robertsonian. There were also some differences in centromeric heterochromatin patterns.The data indicate that these two forms are distinct species, cytogenetically isolated, and that a revision of the taxonomic status of the genus Arvicanthis is needed. 相似文献
2.
Blood lymphocytes in culture were irradiated by gamma-rays 3 h to 30 mn before harvesting. The various induced lesions were analysed, with a particular attention on sticky chromosomes, i.e. radial figures in which chromosomes are not obviously broken, but are linked by a tiny filament. Such anomalies are preferentially induced in mid to late G2-phase. They result from recombinations occurring at nonrandom chromosome regions: junction between hetero- and euchromatin, and telomeric regions. It is proposed that they are formed when double strand breaks are induced while intrachromatidic links have started to be formed in the course of chromosome condensation. If this interpretation is correct, the apparent lack of induced breakage of premitotic chromosomes is artifactual. 相似文献
3.
Leandro Medrano Giacomo Bernardi Jérome Couturier Bernard Dutrillaux Giorgio Bernardi 《Chromosoma》1988,97(2):178-183
The diploid chromosome number of the Chinese raccoon dog varies from 54 (no B chromosomes) to 58 (4 B chromosomes). The B chromosomes are totally heterochromatic. An electron microscopic study was made of the synaptonemal complexes (SC) in spermatocytes of these animals. The SC karyotype consists of 27 regular chromosome pairs (autosomes and the sex chromosomes) plus the B chromosomes. The Bs pair effectively with one another at pachytene, but the SC axes of the B chromosomes are much denser than those of the A chromosomes. Depending on the number of Bs, both bivalents and multivalents have been observed. When three B chromosomes are present in a cell, parallel alignment of all three SCs can be seen. Formation of multivalents indicates high homology among these supernumerary heterochromatic chromosomes. Fusiform bulges are found along unpaired regions of all chromosomes which are particularly pronounced in diplotene. 相似文献
4.
A qualitative study is presented of chromosomal rearrangements induced by gamma-irradiation at 2 Gy and 3 Gy in peripheral blood lymphocytes of the chimpanzee Pan troglodytes. From a sample of 460 cells, karyotyped after R-banding, 1047 rearrangements were detected. Each type of rearrangement is analyzed according to the diagrammatic method previously developed. The non-random nature of the induction of the rearrangements is clear. The chimpanzee seems highly sensitive to the induction of dicentrics. This may be related to the existence, in its karyotype, of sensitive juxta-telomeric heterochromatin, much more frequently affected in the case of formation of dicentrics than of other types of rearrangements. Thus, the evaluation of radiation sensitivity of a given species based only on the yield of dicentrics may not have a general value for chromosomal mutagenesis. 相似文献
5.
6.
7.
8.
9.
E. Viegas-Péquignot M. Jeanpierre A. M. Dutrillaux M. Gerbault-Seureau M. Muleris B. Dutrillaux 《Human genetics》1989,81(4):311-314
Summary A biotinylated probe (L23-21) specific for the 1q12 band of human karyotype was used to detect the 1q segment in interphase
nuclei of breast and colon carcinomas. This probe was selected because trisomy or polysomy 1q is the most frequent chromosomal
change observed in solid tumors. This method enables cancerous cells, including near-diploid ones carrying an unbalanced rearrangement
of 1q, to be easily identified. 相似文献
10.
A cytogenetic study of almost all the Malagasy lemurs, of several representative Lorisiforms and one representative each of Tupaiiforms and Tarsiforms is reported. A phylogenic tree was constructed for all species exceptTarsius syrichta, which could not be related to either Prosimians or Simians. Three branches emerge, independentely or after a short common trunk, from the ancestral karyotype of all the Primates. One branch leads to the Lorisiforms, another to the Lemuriforms and the third to the Tupaïa. The chromosomal evolution of the Lorisiforms which gave rise to the Galagidae and the Lorisidae is of a populational mode, while among the Lemuriforms 4 modes of speciation have occurred: populational for the Indriidae, dichotomic for the Lepilemuridae, bushy for the Lemuridae and a catenary one for the Hapelemurs. 相似文献