全文获取类型
收费全文 | 696篇 |
免费 | 84篇 |
出版年
2021年 | 4篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 7篇 |
2015年 | 23篇 |
2014年 | 22篇 |
2013年 | 31篇 |
2012年 | 38篇 |
2011年 | 39篇 |
2010年 | 23篇 |
2009年 | 26篇 |
2008年 | 21篇 |
2007年 | 29篇 |
2006年 | 25篇 |
2005年 | 29篇 |
2004年 | 28篇 |
2003年 | 28篇 |
2002年 | 27篇 |
2001年 | 21篇 |
2000年 | 20篇 |
1999年 | 18篇 |
1998年 | 8篇 |
1997年 | 11篇 |
1996年 | 8篇 |
1995年 | 9篇 |
1993年 | 12篇 |
1992年 | 15篇 |
1991年 | 22篇 |
1990年 | 12篇 |
1989年 | 19篇 |
1988年 | 19篇 |
1987年 | 14篇 |
1986年 | 12篇 |
1985年 | 17篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1973年 | 5篇 |
1972年 | 4篇 |
1967年 | 4篇 |
1966年 | 3篇 |
1905年 | 3篇 |
排序方式: 共有780条查询结果,搜索用时 31 毫秒
691.
Church KM Holloway LM Matley RC Brower RJ 《Nucleosides, nucleotides & nucleic acids》2004,23(11):1723-1738
Our work outlines the use of oxoammonium salts in a formal 1,2 addition process to olefins giving nucleoside analogs as products. Specifically, oxoammonium salts can be added to a solution of olefin and silylated heterocycle to give Methoxy TEMPO substituted nucleoside analogs after hydrolytic workup and chromatographic purification. 相似文献
692.
Cook DN Wang S Wang Y Howles GP Whitehead GS Berman KG Church TD Frank BC Gaspard RM Yu Y Quackenbush J Schwartz DA 《Genomics》2004,83(6):961-969
To identify novel genes regulating the biologic response to lipopolysaccharide (LPS), we used a combination of quantitative trait locus (QTL) analysis and microarray-based gene expression studies of C57BL/6J x DBA/2J(BXD) F2 and recombinant inbred (RI) mice. A QTL affecting pulmonary TNF-alpha production was identified on chromosome 2, and a region affecting both polymorphonuclear leukocyte recruitment and TNF-alpha levels was identified on chromosome 11. Microarray analyses of unchallenged and LPS-challenged BXD RI strains identified approximately 500 genes whose expression was significantly changed by inhalation of LPS. Of these genes, 28 reside within the chromosomal regions identified by the QTL analyses, implicating these genes as high priority candidates for functional studies. Additional high priority candidate genes were identified based on their differential expression in mice having high and low responses to LPS. Functional studies of these genes are expected to reveal important molecular mechanisms regulating the magnitude of biologic responses to LPS. 相似文献
693.
C. M. S. Plowright F. Landry D. Church J. Heyding N. Dupuis-Roy J. P. Thivierge V. Simonds 《Journal of Insect Behavior》2001,14(1):113-127
In three experiments, bumble bees were trained to discriminate between a reinforcing pattern (S+) and a nonreinforcing one (S–) which differed only in the configuration of four artificial petals. They were subsequently tested for recognition of the S+ rotated by 90° (S + 90). Experiment 1 used petals of four colors, and the other experiments used four symbols. The symbols either remained unchanged when the whole pattern was rotated (e.g., + in Experiment 2) or changed appearance (e.g., < in Experiment 3). The bees failed to recognize the S + 90 in the first two experiments, but in Experiment 3, the choice proportion for S + 90 in the presence of a New pattern was significantly higher than chance. Bumble bees can recognize a rotated pattern, possibly by using mental rotation, provided that a cue as to the extent of the pattern transformation is given. 相似文献
694.
695.
696.
Predicting regulons and their cis-regulatory motifs by comparative genomics 总被引:4,自引:2,他引:2 下载免费PDF全文
We have combined and compared three techniques for predicting functional interactions based on comparative genomics (methods based on conserved operons, protein fusions and correlated evolution) and optimized these methods to predict coregulated sets of genes in 24 complete genomes, including Saccharomyces cerevisiae, Caernorhabditis elegans and 22 prokaryotes. The method based on conserved operons was the most useful for this purpose. Upstream regions of the genes comprising these predicted regulons were then used to search for regulatory motifs in 22 prokaryotic genomes using the motif-discovery program AlignACE. Many significant upstream motifs, including five known Escherichia coli regulatory motifs, were identified in this manner. The presence of a significant regulatory motif was used to refine the members of the predicted regulons to generate a final set of predicted regulons that share significant regulatory elements. 相似文献
697.
The antioxidant responses of human cell differentiation and membrane fusion are not known and may be important in understanding cellular response to injury in the human placenta. We studied the regulation of antioxidant enzymes in human trophoblasts which differentiate from mononucleated cellular trophoblasts to synctium in vivo and in culture. We characterized morphological and biochemical differentiation of cultured trophoblasts from term placenta in the presence or absence of serum, on different growth surfaces, and with a range of plating densities. Culture of cellular trophoblasts consistently and transiently induced the mRNAs of the mitochondrial antioxidant manganese superoxide dismutase (Mn SOD) but not the mRNAs for the antioxidant enzymes copper zinc SOD or catalase. Fibrin and type I collagen substrates modulated only the expression of the placental specific proteins, human chorionic gonadotropin, and human placental lactogen. Both Mn SOD induction and terminal differentiation, as reflected by human chorionic gonadotropin expression, were dependent on trophoblastic plating density. Increased levels of a smaller Mn SOD mRNA species correlated temporally with an increase in Mn SOD enzyme activity in cultured trophoblasts. These results demonstrate that Mn SOD gene expression and enzyme activity precede or are coordinately regulated with morphological and biochemical trophoblastic differentiation. 相似文献
698.
Krishanu Saha J. Benjamin Hurlbut Sheila Jasanoff Aziza Ahmed Anthony Appiah Elizabeth Bartholet Françoise Baylis Gaymon Bennett George Church I. Glenn Cohen George Daley Kevin Finneran William Hurlbut Rudolf Jaenisch Laurence Lwoff John Paul Kimes Peter Mills Jacob Moses Christiane Woopen 《Trends in biotechnology》2018,36(8):741-743
699.
J. Benjamin Hurlbut Sheila Jasanoff Krishanu Saha Aziza Ahmed Anthony Appiah Elizabeth Bartholet Françoise Baylis Gaymon Bennett George Church I. Glenn Cohen George Daley Kevin Finneran William Hurlbut Rudolf Jaenisch Laurence Lwoff John Paul Kimes Peter Mills Jacob Moses Christiane Woopen 《Trends in biotechnology》2018,36(7):639-641
700.
Gregor Sachse Chris Church Michelle Stewart Heather Cater Lydia Teboul Roger D. Cox Frances M. Ashcroft 《生物化学与生物物理学报:疾病的分子基础》2018,1864(3):843-850
The Fto gene locus has been linked to increased body weight and obesity in human population studies, but the role of the actual FTO protein in adiposity has remained controversial. Complete loss of FTO protein in mouse and of FTO function in human patients has multiple and variable effects. To determine which effects are due to the ability of FTO to demethylate mRNA, we genetically engineered a mouse with a catalytically inactive form of FTO. Our results demonstrate that FTO catalytic activity is not required for normal body composition although it is required for normal body size and viability. Strikingly, it is also essential for normal bone growth and mineralization, a previously unreported FTO function. 相似文献