全文获取类型
收费全文 | 1674篇 |
免费 | 158篇 |
国内免费 | 3篇 |
出版年
2023年 | 9篇 |
2022年 | 29篇 |
2021年 | 44篇 |
2020年 | 18篇 |
2019年 | 29篇 |
2018年 | 32篇 |
2017年 | 34篇 |
2016年 | 59篇 |
2015年 | 70篇 |
2014年 | 81篇 |
2013年 | 107篇 |
2012年 | 106篇 |
2011年 | 115篇 |
2010年 | 96篇 |
2009年 | 70篇 |
2008年 | 87篇 |
2007年 | 99篇 |
2006年 | 73篇 |
2005年 | 69篇 |
2004年 | 65篇 |
2003年 | 52篇 |
2002年 | 42篇 |
2001年 | 24篇 |
2000年 | 27篇 |
1999年 | 18篇 |
1998年 | 16篇 |
1997年 | 9篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 12篇 |
1992年 | 16篇 |
1991年 | 14篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 23篇 |
1984年 | 18篇 |
1982年 | 13篇 |
1981年 | 14篇 |
1980年 | 18篇 |
1979年 | 16篇 |
1978年 | 8篇 |
1977年 | 13篇 |
1976年 | 10篇 |
1975年 | 15篇 |
1974年 | 16篇 |
1973年 | 13篇 |
排序方式: 共有1835条查询结果,搜索用时 265 毫秒
11.
Association of Alleles of the Malic Dehydrogenase Locus with a Pericentric Inversion in DROSOPHILA ROBUSTA 下载免费PDF全文
Associations of Malic dehydrogenase alleles with the third chromosome arrangement 3R and the pericentric arrangement 3L-R are described. Even though significant associations between alleles and inversions exist within a population, there is an overall similarity in MDH allele frequencies in different populations inspite of large differences in inversion frequencies. 相似文献
12.
Summary Early meiotic stages of Arbacia punctulata oocytes have revealed the presence of synaptinemal complexes in the chromosomes, which persist through zygotene-pachytene. The synaptinemal complexes conform broadly to the usual tripartite structures found in other higher forms. In addition, nuclei at these stages consist of a small nucleolus and dense bodies of varying sizes. The nucleolus is fibrillar in texture throughout and does not seem to incorporate Uridine-5-3H after pulse labeling, whereas the chromosomes are labeled. The nucleolar label is visualized at diplotene stages and onwards. The nuclear envelope differentiates by the appearance of numerous nuclear pore complexes with dense material in the annuli, and the chromosomes become markedly diffused. At vitellogenesis stage the nucleolus and chromatin become highly labeled after pulse incorporation of Uridine, indicating synthesis of ribosomal and chromosomal RNAs.This investigation was supported by grants No. A-5049, A-3624 and D-17 from National Research Council, Canada, grant No. DRB-9340-05 (U6) from Defense Research Board, Canada, and grant No. DRG-918 AT from Damon Runyon Memorial Fund for Cancer Research. 相似文献
13.
14.
15.
Satya Prakash 《Genetics》1967,57(2):385-400
16.
17.
18.
19.
Insulin-like growth factor-I supports proliferation of autocrine thymic lymphoma cells with a pre-T cell phenotype 总被引:4,自引:0,他引:4
R A Gjerset J Yeargin S K Volkman V Vila J Arya M Haas 《Journal of immunology (Baltimore, Md. : 1950)》1990,145(10):3497-3501
We have studied the phenotypic characteristics and growth properties of murine T lymphoma cell lines derived from primary x-ray-induced thymic lymphomas at the earliest stage at which they can be detected, and well before spreading to other organs has occurred. These cell lines serve as model systems for the earliest events in T cell lymphoma induction, before tumor cell progression and spreading to other organs. We find that primary x-ray-induced T cell lymphoma lines have phenotypic characteristics of thymic pre-T cells and show no proliferative response to any of the IL tested nor to other hematopoietic growth factors. However, they do proliferate in response to insulin-like growth factor I (IGF-I) and to a small autocrine peptide distinct from IGF-I, which we term lymphoma growth factor. One of the earliest lesions in T cell lymphoma induction may therefore be an inhibition of differentiation at one of several specific points. In its early stages, T lymphoma cell growth may be restricted to an environment where local concentrations of specific growth factors such as IGF-I or lymphoma growth factor are sufficiently high. 相似文献
20.