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   153篇
  免费   0篇
  国内免费   1篇
丛书文集   2篇
理论与方法论   2篇
现状及发展   53篇
研究方法   13篇
综合类   82篇
自然研究   2篇
  2012年   2篇
  2011年   10篇
  2010年   1篇
  2009年   1篇
  2008年   8篇
  2007年   6篇
  2006年   9篇
  2005年   4篇
  2004年   5篇
  2003年   5篇
  2002年   4篇
  2001年   5篇
  2000年   5篇
  1999年   1篇
  1995年   1篇
  1992年   1篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   6篇
  1985年   2篇
  1984年   1篇
  1982年   1篇
  1980年   1篇
  1979年   3篇
  1978年   9篇
  1977年   1篇
  1976年   5篇
  1974年   5篇
  1973年   2篇
  1972年   3篇
  1971年   15篇
  1970年   8篇
  1969年   9篇
  1968年   3篇
  1967年   1篇
  1966年   2篇
  1965年   1篇
  1964年   2篇
  1963年   2篇
  1958年   1篇
排序方式: 共有154条查询结果,搜索用时 15 毫秒
31.
A module map showing conditional activity of expression modules in cancer   总被引:27,自引:0,他引:27  
Segal E  Friedman N  Koller D  Regev A 《Nature genetics》2004,36(10):1090-1098
DNA microarrays are widely used to study changes in gene expression in tumors, but such studies are typically system-specific and do not address the commonalities and variations between different types of tumor. Here we present an integrated analysis of 1,975 published microarrays spanning 22 tumor types. We describe expression profiles in different tumors in terms of the behavior of modules, sets of genes that act in concert to carry out a specific function. Using a simple unified analysis, we extract modules and characterize gene-expression profiles in tumors as a combination of activated and deactivated modules. Activation of some modules is specific to particular types of tumor; for example, a growth-inhibitory module is specifically repressed in acute lymphoblastic leukemias and may underlie the deregulated proliferation in these cancers. Other modules are shared across a diverse set of clinical conditions, suggestive of common tumor progression mechanisms. For example, the bone osteoblastic module spans a variety of tumor types and includes both secreted growth factors and their receptors. Our findings suggest that there is a single mechanism for both primary tumor proliferation and metastasis to bone. Our analysis presents multiple research directions for diagnostic, prognostic and therapeutic studies.  相似文献   
32.
内蒙赤峰南部楼子店拆离断层系绿泥石化带的形成时代   总被引:7,自引:0,他引:7  
楼子店拆离断层系是华北陆块北缘一条大型北东南西向构造,低角度倾向南东.拆离断层系中韧性剪切带的走向线理与脆性断面上的倾向擦痕表明该断层发育过程中发生了运动学上的转向.拆离断层系绿泥石化带是伸展过程中构造层次递进变浅所致的退化变质作用产物,其中发育了早期近走向和晚期倾向两组线理,记录了上盘早期向北东的韧性剪切到晚期脆性倾向下滑的运动学转向过程.因此,绿泥石矿物的定年可限定这一构造热事件及运动学转向的时间.初步的绿泥石K-Ar定年表明,楼子店拆离断层系绿泥石化带形成始于~121Ma,114—112Ma间发生了运动学的转向.  相似文献   
33.
34.
35.
医用胶粘剂主体材料α-氰基丙烯酸正辛酯的合成研究   总被引:2,自引:0,他引:2  
以氰乙酸正辛酯为原料,通过改进合成反应条件,合成得到了一种医用胶粘剂主体材料α-氰基丙烯酸正辛酯,产率达到了71.2%,为下一步α-氰基丙烯酸酯胶粘剂性能改进奠定了基础.  相似文献   
36.
37.
Nanotechnology: high-speed integrated nanowire circuits   总被引:1,自引:0,他引:1  
Macroelectronic circuits made on substrates of glass or plastic could one day make computing devices ubiquitous owing to their light weight, flexibility and low cost. But these substrates deform at high temperatures so, until now, only semiconductors such as organics and amorphous silicon could be used, leading to poor performance. Here we present the use of low-temperature processes to integrate high-performance multi-nanowire transistors into logical inverters and fast ring oscillators on glass substrates. As well as potentially enabling powerful electronics to permeate all aspects of modern life, this advance could find application in devices such as low-cost radio-frequency tags and fully integrated high-refresh-rate displays.  相似文献   
38.
Dominant modifier DFNM1 suppresses recessive deafness DFNB26   总被引:8,自引:0,他引:8  
More than 50% of severe childhood deafness is genetically determined, approximately 70% of which occurs without other abnormalities and is thus termed nonsyndromic. So far, 30 nonsyndromic recessive deafness loci have been mapped and the defective genes at 6 loci, DFNB1, DFNB2, DFNB3, DFNB4, DFNB9 and DNFB21, have been identified, encoding connexin-26 (ref. 3), myosin VIIA (ref. 4), myosin XV (ref. 5), pendrin, otoferlin and alpha-tectorin, respectively. Here we map a new recessive nonsyndromic deafness locus, DFNB26, to a 1.5-cM interval of chromosome 4q31 in a consanguineous Pakistani family. A maximum lod score of 8.10 at theta=0 was obtained with D4S1610 when only the 8 affected individuals in this family were included in the calculation. There are seven unaffected family members who are also homozygous for the DFNB26-linked haplotype and thus are non-penetrant. A dominant modifier, DFNM1, that suppresses deafness in the 7 nonpenetrant individuals was mapped to a 5.6-cM region on chromosome 1q24 with a lod score of 4.31 at theta=0 for D1S2815.  相似文献   
39.
40.
Oxidant damage mediates variant red cell resistance to malaria.   总被引:8,自引:0,他引:8  
M J Friedman 《Nature》1979,280(5719):245-247
  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