全文获取类型
收费全文 | 627篇 |
免费 | 0篇 |
国内免费 | 15篇 |
专业分类
化学 | 358篇 |
物理学 | 284篇 |
出版年
2012年 | 35篇 |
2011年 | 50篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 54篇 |
2007年 | 57篇 |
2006年 | 55篇 |
2005年 | 54篇 |
2004年 | 38篇 |
2003年 | 31篇 |
2002年 | 24篇 |
2001年 | 15篇 |
2000年 | 35篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 12篇 |
1995年 | 16篇 |
1994年 | 17篇 |
1993年 | 27篇 |
1992年 | 26篇 |
1991年 | 9篇 |
1990年 | 16篇 |
1989年 | 11篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1969年 | 1篇 |
1966年 | 2篇 |
1948年 | 3篇 |
排序方式: 共有642条查询结果,搜索用时 156 毫秒
591.
592.
593.
594.
595.
596.
597.
598.
599.
Huang KS Weinger JS Butler EB Strobel SA 《Journal of the American Chemical Society》2006,128(10):3108-3109
The ribosomal peptidyl transferase center is expected to be regiospecific with regard to its tRNA substrates, yet the ester linkages between the tRNA and the amino acid or peptide are susceptible to isomerization between the O2' and O3' hydroxyls of the terminal A76 ribose sugar. To establish which isomer of the P site tRNA ester is utilized by the ribosome, we prepared two nonisomerizable transition state inhibitors with either an A76 O2' or O3' linkage. Strong preferential binding to the O3' regioisomer indicates that the peptidyl transferase proceeds through a transition state with an O3'-linked peptide in the P-site. 相似文献
600.
Gebel EB Ruan K Tolman JR Shortle D 《Journal of the American Chemical Society》2006,128(29):9310-9311
The structural content of the denatured state has yet to be fully characterized. In recent years, large residual dipolar couplings (RDCs) from denatured proteins have been observed under alignment conditions produced by bicelles and strained polyacrylamide gels. In this report, we describe efforts to extend our picture of the residual structure in denatured nuclease by measuring RDCs with multiple alignment tensors. Backbone amide 15N-1H RDCs were collected from 4 M urea for a total of eight RDC data sets. The RDCs were analyzed by singular value decomposition (SVD) to determine the number of independent alignment tensors present in the data. On the basis of the resultant singular values and propagated error estimates, it is clear that there are at least three independent alignment tensors. These three independent RDC datasets can be reconstituted as orthogonal linear combinations, (OLC)-RDC datasets, of the eight actually recorded. The first, second, and third OLC-RDC datasets are highly robust to the removal of any single experimental RDC dataset, establishing the presence of three independent alignment tensors, sampled well above the level of experimental uncertainty. The observation that the RDC data span three or more dimensions of the five-dimensional parameter space demonstrates that the ensemble average structure of denatured nuclease must be asymmetric with respect to these three orthogonal principal axes, which is not inconsistent with earlier work demonstrating that it has a nativelike topology. 相似文献