全文获取类型
收费全文 | 214篇 |
免费 | 1篇 |
专业分类
教育与普及 | 2篇 |
现状及发展 | 84篇 |
研究方法 | 21篇 |
综合类 | 107篇 |
自然研究 | 1篇 |
出版年
2017年 | 1篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 14篇 |
2007年 | 14篇 |
2006年 | 10篇 |
2005年 | 9篇 |
2004年 | 13篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 4篇 |
2000年 | 11篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1977年 | 6篇 |
1976年 | 9篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 5篇 |
1970年 | 5篇 |
1969年 | 5篇 |
1968年 | 1篇 |
排序方式: 共有215条查询结果,搜索用时 15 毫秒
21.
22.
Electron microscopic observations revealed for the first time a small number of active melanocytes synthesizing distinctive melanin-containing organelles (melanin granules)in the ducts and acini of human sebaceous glands. 相似文献
23.
Summary The injection of testosterone propionate for 4 successive days into female rats resulted in an increase of the in vitro conversion of the hydroxylated testosterones from testosterone by the hepatic microsomal, fraction, but no change in the content of microsomal cytochrome P-450 occurred. Actinomycin D or puromycin, which was administered for 4 days with injections of testosterone propionate, prevented the enzyme induction. 相似文献
24.
Cytological evidence on the ability of the nucleolus organizing regions to assemble pre-existing nucleolar material 总被引:1,自引:0,他引:1
S. Sato 《Cellular and molecular life sciences : CMLS》1988,44(3):264-266
Summary The treatment ofVicia faba root tips with 5-azacytidine caused unequal allotment of the chromosomes; after one cell cycle, a pair of daughter nuclei was produced, one of which carried the nucleolus organizing regions (NORs) and the other of which lacked them. The pre-existing nucleolar material brought into the NOR-carrying daughter nucleus by the chromosomes disappeared concurrently with the appearance of the new nucleoli, whereas in another daughter nucleus without the NOR a number of small nucleolus-like bodies became visible at random positions. These findings suggest that in addition to ribosomal RNA synthesis the NOR has another role in cells; to stimulate the pre-existing nucleolar material to assemble at the NOR itself. 相似文献
25.
Summary Renal glucose-6-phosphatase activity was found to be significantly elevated by fluoride administration (NaF 35 mg/kg, i.p.). The elevation of the enzyme activity was markedly suppressed by adrenalectomy.This work was supported in part by the Scientific Research Foundation (Grant 7014-267337) from the Education and Culture Ministry of Japan. 相似文献
26.
27.
Epstein-Barr virus transforms precursor B cells even before immunoglobulin gene rearrangements 总被引:2,自引:0,他引:2
The very early stages of the human B-cell differentiation pathway are poorly understood, primarily because of the lack of appropriate permanent cell lines. Epstein-Barr virus (EBV) is a putative human oncogenic virus which transforms human B cells in vitro into continuously proliferating cells. It has been believed that EBV transforms mature B cells, but recently, transformation of immature pre-B-cell lines has been reported, suggesting that EBV might also transform cells much earlier in the B-cell lineage. We report here the establishment of cell lines transformed by EBV at various stages of the B-cell differentiation pathway. Interestingly, two lines showed the complete absence of immunoglobulin synthesis and the lack of immunoglobulin gene rearrangement despite containing EBV genome and surface markers of B cells. Our results indicate that EBV can infect and transform cells of the B lymphocyte lineage even before immunoglobulin gene rearrangement. 相似文献
28.
Cytological evidence on the ability of the nucleolus organizing regions to assemble pre-existing nucleolar material 总被引:1,自引:0,他引:1
S Sato 《Experientia》1988,44(3):264-266
The treatment of Vicia faba root tips with 5-azacytidine caused unequal allotment of the chromosomes; after one cell cycle, a pair of daughter nuclei was produced, one of which carried the nucleolus organizing regions (NORs) and the other of which lacked them. The pre-existing nucleolar material brought into the NOR-carrying daughter nucleus by the chromosomes disappeared concurrently with the appearance of the new nucleoli, whereas in another daughter nucleus without the NOR a number of small nucleolus-like bodies became visible at random positions. These findings suggest that in addition to ribosomal RNA synthesis the NOR has another role in cells; to stimulate the pre-existing nucleolar material to assemble at the NOR itself. 相似文献
29.
Y. Komai H. Sato N. Hiraiwa Y. Sawaishi 《Cellular and molecular life sciences : CMLS》1971,27(8):881-882
Zusammenfassung Wasserlösliche, proteolipide Proteine wurden von der weissen Hirnsubstanz durch Isolierungsmethoden vonTenenbaum undFolch
2 gewonnen. Ohne Lyophilisation ergab die Disk-Elektrophorese bei pH 8.3 zwei Banden.
The authors express their appreciation to Dr.K. Ueki, Dr.Y. Takahashi, Dr.Y. Takemoto and Dr.T. Kotoku. 相似文献
The authors express their appreciation to Dr.K. Ueki, Dr.Y. Takahashi, Dr.Y. Takemoto and Dr.T. Kotoku. 相似文献
30.
Brood parasitism, where a brood of the parasitic species is fostered by the parents of another species, is well known among birds. In most cases, such offspring show a complete reliance upon their host parents for food, protection and warmth until their independence. In other vertebrate groups, however, such total dependence upon a host species is unknown. I report here the first example of true brood parasitic behaviour discovered among fishes. In Lake Tanganyika, an endemic mochokid catfish, Synodontis multipunctatus Boulenger, is a brood parasite of mouthbrooding fishes of the family Cichlidae. The eggs of the catfish are incubated in the mouths of any of several host species together with the host's eggs, but hatch earlier. Following absorption of their yolk sacs, the catfish fry feed upon the fry of the host while still in its mouth. Thus the early stages of development of this catfish not only depend upon their hosts for food and protection, but exploit almost their entire parental investment. 相似文献