全文获取类型
收费全文 | 438篇 |
免费 | 29篇 |
国内免费 | 1篇 |
专业分类
468篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 18篇 |
2014年 | 18篇 |
2013年 | 21篇 |
2012年 | 32篇 |
2011年 | 24篇 |
2010年 | 17篇 |
2009年 | 15篇 |
2008年 | 29篇 |
2007年 | 17篇 |
2006年 | 21篇 |
2005年 | 20篇 |
2004年 | 10篇 |
2003年 | 11篇 |
2002年 | 15篇 |
2001年 | 16篇 |
2000年 | 19篇 |
1999年 | 14篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1992年 | 9篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1987年 | 1篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 6篇 |
1972年 | 1篇 |
1970年 | 3篇 |
1960年 | 1篇 |
排序方式: 共有468条查询结果,搜索用时 8 毫秒
91.
92.
In this work it is proposed that in evolution amino acid substitutions implying strong physico chemical and structural differences are more relevant and more frequent than substitutions between similar amino acids. This analysis is made over a group of protein families representing about 10 000 substitutions and as examples the evolutionary trees of fibrinopeptides A and calcitonins were constructed and compared. 相似文献
93.
Satoru Kanai Reiko Kikuno Hiroyuki Toh Haruko Ryo Takeshi Todo 《Journal of molecular evolution》1997,45(5):535-548
The photolyase–blue-light photoreceptor family is composed of cyclobutane pyrimidine dimer (CPD) photolyases, (6-4) photolyases,
and blue-light photoreceptors. CPD photolyase and (6-4) photolyase are involved in photoreactivation for CPD and (6-4) photoproducts,
respectively. CPD photolyase is classified into two subclasses, class I and II, based on amino acid sequence similarity. Blue-light
photoreceptors are essential light detectors for the early development of plants. The amino acid sequence of the receptor
is similar to those of the photolyases, although the receptor does not show the activity of photoreactivation. To investigate
the functional divergence of the family, the amino acid sequences of the proteins were aligned. The alignment suggested that
the recognition mechanisms of the cofactors and the substrate of class I CPD photolyases (class I photolyases) are different
from those of class II CPD photolyases (class II photolyases). We reconstructed the phylogenetic trees based on the alignment
by the NJ method and the ML method. The phylogenetic analysis suggested that the ancestral gene of the family had encoded
CPD photolyase and that the gene duplication of the ancestral proteins had occurred at least eight times before the divergence
between eubacteria and eukaryotes.
Received: 23 October 1996 / Accepted: 1 April 1997 相似文献
94.
95.
Zymomonas mobilis growing aerobically with 20 g glucose–1 (carbon-limited) in a chemostat exhibited an increase in both the molar growth yield (Yx/s) and the maximum molar growth yield (Yx/s
max) and a decrease in both the specific substrate consumption rate (qs) and the maintenance energy consumption rate (me). Stepwise increase in the input oxygen partial pressure showed that anaerobic-to-aerobic transitional adaptation occurred
in four stages: anaerobic (0 mm HgO2), oxygen-limited (7.6– 230 mm HgO2), intermediate (273 mm HgO2), and oxygen excess (290 mm HgO2). The steady-state biomass concentration, Yx/s, and intracellular ATP content increased between oxygen partial pressures of 7.6 and 120 mm HgO2, accompanied by a decrease in the qs and the specific acid production rate. The membrane ATPase activity decreased with increasing oxygen partial pressure and
reached its lowest levels at 273 mm HgO2, which was the highest input oxygen partial pressure where steady-state conditions were possible. Glucokinase, glucose-6-phosphate
dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, and alcohol dehydrogenase activities also decreased when the oxygen
partial pressure was increased above 15 mm Hg, whereas pyruvate decarboxylase was unaffected by aeration. Growth inhibition
at 290 mm HgO2 was characterised by a drastic reduction in the pyruvate kinase activity and a collapse in the intracellular ATP pool. The
growth and enzyme data suggest that at low glucose concentrations and oxygen-limited conditions, the increase in biomass yields
is a reflection of a redirection of ATP usage rather than a net increase in energy production.
Received: 14 August 1996 / Accepted: 31 January 1997 相似文献
96.
Toh Zhi Yon Charles May Thandar Aung-Htut Gavin Pinniger Abbie M. Adams Sudarsan Krishnaswarmy Brenda L. Wong Sue Fletcher Steve D. Wilton 《PloS one》2016,11(1)
Duchenne and Becker muscular dystrophy severity depends upon the nature and location of the DMD gene lesion and generally correlates with the dystrophin open reading frame. However, there are striking exceptions where an in-frame genomic deletion leads to severe pathology or protein-truncating mutations (nonsense or frame-shifting indels) manifest as mild disease. Exceptions to the dystrophin reading frame rule are usually resolved after molecular diagnosis on muscle RNA. We report a moderate/severe Becker muscular dystrophy patient with an in-frame genomic deletion of DMD exon 5. This mutation has been reported by others as resulting in Duchenne or Intermediate muscular dystrophy, and the loss of this in-frame exon in one patient led to multiple splicing events, including omission of exon 6, that disrupts the open reading frame and is consistent with a severe phenotype. The patient described has a deletion of dystrophin exon 5 that does not compromise recognition of exon 6, and although the deletion does not disrupt the reading frame, his clinical presentation is more severe than would be expected for classical Becker muscular dystrophy. We suggest that the dystrophin isoform lacking the actin-binding sequence encoded by exon 5 is compromised, reflected by the phenotype resulting from induction of this dystrophin isoform in mouse muscle in vivo. Hence, exon skipping to address DMD-causing mutations within DMD exon 5 may not yield an isoform that confers marked clinical benefit. Additional studies will be required to determine whether multi-exon skipping strategies could yield more functional dystrophin isoforms, since some BMD patients with larger in-frame deletions in this region have been reported with mild phenotypes. 相似文献
97.
98.
99.
The effect of incubation temperature on the background staining of Western blots with monoclonal antibodies to a human milk protein, alpha-lactalbumin (Mr 14,500), is presented. Human milk proteins were electrophoretically separated and transferred to nitrocellulose membranes which were then blocked with bovine serum albumin, "BLOTTO", casein, or Tween 20. They were subsequently incubated with mouse monoclonal antibody to human alpha-lactalbumin, biotinylated anti-mouse antibody, strepavidin-biotinylated horseradish peroxidase complexes and a substrate containing diaminobenzidine and nickel chloride. Reduction of incubation temperature from 37 degrees C to 22 degrees C and 4 degrees C was found to decrease the extent of non-specific background staining independent of the type of blocking reagent used. Good specific staining with minimal background was found using 0.1% Tween 20 in phosphate-buffered saline, pH 7.2, as blocking agent and incubation temperatures of 4 degrees C. 相似文献
100.