首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   117篇
  免费   0篇
  国内免费   4篇
系统科学   1篇
教育与普及   1篇
理论与方法论   3篇
现状及发展   61篇
研究方法   5篇
综合类   49篇
自然研究   1篇
  2018年   3篇
  2017年   3篇
  2016年   3篇
  2015年   2篇
  2014年   1篇
  2013年   6篇
  2012年   9篇
  2011年   13篇
  2010年   5篇
  2009年   3篇
  2008年   11篇
  2007年   7篇
  2006年   2篇
  2005年   3篇
  2004年   3篇
  2003年   4篇
  2002年   5篇
  1996年   1篇
  1991年   2篇
  1990年   1篇
  1986年   1篇
  1985年   1篇
  1984年   2篇
  1982年   3篇
  1981年   2篇
  1980年   3篇
  1979年   5篇
  1978年   3篇
  1977年   1篇
  1975年   4篇
  1974年   2篇
  1973年   2篇
  1972年   1篇
  1970年   1篇
  1967年   2篇
  1948年   1篇
排序方式: 共有121条查询结果,搜索用时 125 毫秒
41.
Summary Several polyoxygenated steroids (1, 2, 3) have been isolated from the marine gorgonianLeptogorgia sarmentosa. One of these (1) is the known guggulsterol III, previously found in the pharmacologically active resin from the treeCommiphora mukul; the others,2 and3, have not been found before in nature, and are closely related to1. During the structural work apparent anomalies in the CMR-spectra of1 were observed.The authors are grateful to Prof. Sukh Dev for the PMR-spectra of guggulsterol III. Thanks are also due to Zoological Station (Naples), for the collection of the gorgonian, to Centro Metodologie Chimico-Fisiche, Università di Napoli, for recording PMR-spectra on WH-270 Superconducting Spectrometer-Bruker, to Mr C. Di Pinto for the CMR-spectra and to Mr A. Milone for the MS spectral measurements.  相似文献   
42.
Summary The present study demonstrates that methionine enkephalin can inhibit the normal bursting activity pattern of the RPal or Br-type neuron and this inhibition can be blocked by prior treatment with naloxone, the selective opiate antagonist. The study demonstrates indirectly the presence of opiate-like receptors inHelix pomatia.Acknowledgments. This work was funded by grant RR 08171 Division of Research Resources and NIMH, and a National Academy of Sciences Travel grant and a Hungarian Academy of Sciences research support award to G.B.S. We also gratefully acknowledge thoughtful comments from Dr J. Salanki.  相似文献   
43.
44.
45.
Riassunto Viene descritto l'isolamento del 2-tetraprenil-1,4-benzochinone, del corrispondente idrochinone e dell' acido 4-idrossi-3-tetraprenilbenzoico dalla spugnaIrcinia muscarum. Il rinvenimento di quest'ultimo suggerisce che il precursore dell'anello dei chinoni prenilati non sostituiti e dei loro corrispondenti idrochinoni, ritrovati nelle spugne, sia l'acidop-idrossibenzoico, come nel caso degli ubichinoni. Vengono, inoltre, riportate alcune considerazioni sulle possibili relazioni biogenetiche nelle spugne tra gli ubichinoni e questi insoliti chinoni.  相似文献   
46.
47.
48.
49.
50.
Multiple myeloma is an incurable malignancy of plasma cells, and its pathogenesis is poorly understood. Here we report the massively parallel sequencing of 38 tumour genomes and their comparison to matched normal DNAs. Several new and unexpected oncogenic mechanisms were suggested by the pattern of somatic mutation across the data set. These include the mutation of genes involved in protein translation (seen in nearly half of the patients), genes involved in histone methylation, and genes involved in blood coagulation. In addition, a broader than anticipated role of NF-κB signalling was indicated by mutations in 11 members of the NF-κB pathway. Of potential immediate clinical relevance, activating mutations of the kinase BRAF were observed in 4% of patients, suggesting the evaluation of BRAF inhibitors in multiple myeloma clinical trials. These results indicate that cancer genome sequencing of large collections of samples will yield new insights into cancer not anticipated by existing knowledge.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号