全文获取类型
收费全文 | 179篇 |
免费 | 0篇 |
国内免费 | 3篇 |
专业分类
系统科学 | 9篇 |
现状及发展 | 27篇 |
研究方法 | 43篇 |
综合类 | 98篇 |
自然研究 | 5篇 |
出版年
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2012年 | 15篇 |
2011年 | 30篇 |
2010年 | 5篇 |
2008年 | 19篇 |
2007年 | 20篇 |
2006年 | 20篇 |
2005年 | 9篇 |
2004年 | 15篇 |
2003年 | 6篇 |
2002年 | 16篇 |
2001年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1988年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1956年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有182条查询结果,搜索用时 359 毫秒
51.
We give an overview of the main data of a publication-citation matrix. We show how impact factors are defined, and, in particular, point out the difference between the synchronous and the diachronous impact factor. The advantages and disadvantages of using both as tools in research evaluation are discussed. 相似文献
52.
53.
54.
Berger MF Lawrence MS Demichelis F Drier Y Cibulskis K Sivachenko AY Sboner A Esgueva R Pflueger D Sougnez C Onofrio R Carter SL Park K Habegger L Ambrogio L Fennell T Parkin M Saksena G Voet D Ramos AH Pugh TJ Wilkinson J Fisher S Winckler W Mahan S Ardlie K Baldwin J Simons JW Kitabayashi N MacDonald TY Kantoff PW Chin L Gabriel SB Gerstein MB Golub TR Meyerson M Tewari A Lander ES Getz G Rubin MA Garraway LA 《Nature》2011,470(7333):214-220
55.
56.
Zusammenfassung Die Mortalität an Leukämie bei BALB/c-Mäusen wurde durch wöchentliche i.p. Injektionen mit menschlichen Erythrozyten herabgesetzt, wenn sie während 8 Monaten vor der Impfung mitRauscher-Leukämievirus vorbehandelt waren. 7 Monate nach der Virusinfektion zeigten 20% dieser Mäuse keine Zeichen von Leukämie. Kontrollversuche mit der gleichen Serie von Injektionen von Ochsenserumalbumin zeigten keinen Schutz. 相似文献
57.
58.
60.
Bowler C Allen AE Badger JH Grimwood J Jabbari K Kuo A Maheswari U Martens C Maumus F Otillar RP Rayko E Salamov A Vandepoele K Beszteri B Gruber A Heijde M Katinka M Mock T Valentin K Verret F Berges JA Brownlee C Cadoret JP Chiovitti A Choi CJ Coesel S De Martino A Detter JC Durkin C Falciatore A Fournet J Haruta M Huysman MJ Jenkins BD Jiroutova K Jorgensen RE Joubert Y Kaplan A Kröger N Kroth PG La Roche J Lindquist E Lommer M Martin-Jézéquel V Lopez PJ Lucas S Mangogna M McGinnis K 《Nature》2008,456(7219):239-244
Diatoms are photosynthetic secondary endosymbionts found throughout marine and freshwater environments, and are believed to be responsible for around one-fifth of the primary productivity on Earth. The genome sequence of the marine centric diatom Thalassiosira pseudonana was recently reported, revealing a wealth of information about diatom biology. Here we report the complete genome sequence of the pennate diatom Phaeodactylum tricornutum and compare it with that of T. pseudonana to clarify evolutionary origins, functional significance and ubiquity of these features throughout diatoms. In spite of the fact that the pennate and centric lineages have only been diverging for 90 million years, their genome structures are dramatically different and a substantial fraction of genes ( approximately 40%) are not shared by these representatives of the two lineages. Analysis of molecular divergence compared with yeasts and metazoans reveals rapid rates of gene diversification in diatoms. Contributing factors include selective gene family expansions, differential losses and gains of genes and introns, and differential mobilization of transposable elements. Most significantly, we document the presence of hundreds of genes from bacteria. More than 300 of these gene transfers are found in both diatoms, attesting to their ancient origins, and many are likely to provide novel possibilities for metabolite management and for perception of environmental signals. These findings go a long way towards explaining the incredible diversity and success of the diatoms in contemporary oceans. 相似文献