全文获取类型
收费全文 | 23777篇 |
免费 | 1696篇 |
国内免费 | 11篇 |
出版年
2023年 | 56篇 |
2022年 | 194篇 |
2021年 | 434篇 |
2020年 | 264篇 |
2019年 | 323篇 |
2018年 | 571篇 |
2017年 | 410篇 |
2016年 | 710篇 |
2015年 | 1183篇 |
2014年 | 1296篇 |
2013年 | 1506篇 |
2012年 | 1938篇 |
2011年 | 1840篇 |
2010年 | 1166篇 |
2009年 | 958篇 |
2008年 | 1452篇 |
2007年 | 1286篇 |
2006年 | 1156篇 |
2005年 | 1084篇 |
2004年 | 1055篇 |
2003年 | 895篇 |
2002年 | 885篇 |
2001年 | 744篇 |
2000年 | 730篇 |
1999年 | 506篇 |
1998年 | 198篇 |
1997年 | 155篇 |
1996年 | 150篇 |
1995年 | 108篇 |
1994年 | 107篇 |
1993年 | 94篇 |
1992年 | 208篇 |
1991年 | 181篇 |
1990年 | 144篇 |
1989年 | 163篇 |
1988年 | 121篇 |
1987年 | 114篇 |
1986年 | 116篇 |
1985年 | 90篇 |
1984年 | 74篇 |
1983年 | 77篇 |
1982年 | 55篇 |
1981年 | 47篇 |
1979年 | 55篇 |
1978年 | 41篇 |
1977年 | 50篇 |
1976年 | 43篇 |
1973年 | 51篇 |
1971年 | 46篇 |
1970年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
J.-Y. Roh H.-W. Park Y.-H. Je D.-W. Lee B.-R. Jin H.-W. Oh S. S. Gill & S.-K. Kang 《Letters in applied microbiology》1997,24(6):451-454
Bacillus thuringiensis NTB-1 isolated from soil samples in Korea produces ovoidal parasporal inclusions with proteins of approximately 24–40 kDa in size. Although serological study indicated that the isolate has a flagella (H) antigen identical with subsp. israelensis , it seemed to be non-insecticidal against Lepidoptera and Coleoptera as well as Diptera. To investigate the activity of non-insecticidal B. thuringiensis transformed with insecticidal crystal protein genes, cryIVD and cytA genes of B. thuringiensis subsp. morrisoni PG-14, highly toxic to mosquito larvae, were introduced into the isolate NTB-1. The expression of mosquitocidal crystal protein genes in NTB-1 was characterized by SDS–PAGE analysis and electron microscopy. The results showed that crystalline inclusions of host, CryIVD and CytA were stably expressed in the transformant. However, the mosquitocidal activity of transformant was similar to that of B. thuringiensis subsp. kurstaki Cry− B harbouring cryIVD and cytA genes, demonstrating that a synergistic effect by an interaction of both introduced insecticidal and resident non-insecticidal crystal proteins was not observed. 相似文献
22.
An assessment of the growth rate spectrum based on a longitudinal weight study of golden hamsters was undertaken over the preweaning period. The period covered 23 days with data probes at 24-hourly intervals and encompassed 16 litters providing a birth number of 120 young and a weaning survival number of 82. Subsequent analysis directed initially at the pooled or averaged data showed sex differences with males gaining weight faster than females. Further analysis showed the total period to have three definitive break-points and therefore four phases of growth activity. The segmented linear regression line calculations showed that the phasic duration of males in the second and third phases were two days later than the females. Following data-analysis adjustments and taken into account aberrations of the sample, final indications pointed to the preweaning hamster growth spectrum as quadrophasic, exhibiting a stable first phase, a second and third phase terminating earlier in females and a final weaning weight being heavier in males. The growth curves demonstrated a 'U' shaped outline and formed an integral part of hamster preweaning precocity. 相似文献
23.
Porin, an intrinsic protein of outer mitochondrial membranes of rat liver, was synthesized in vitro in a cell-free in a cell-free translation system with rat liver RNA. The apparent molecular mass of porin synthesized in vitro was the same as that of its mature form (34 kDa). This porin was post-translationally integrated into the outer membrane of rat liver mitochondria when the cell-free translation products were incubated with mitochondria at 30 degrees C even in the presence of a protonophore (carbonyl cyanide m-chlorophenylhydrazone). Therefore, the integration of porin seemed to proceed energy-independently as reported by Freitag et al. [(1982) Eur. J. Biochem. 126, 197-202]. Its integration seemed, however, to require the participation of the inner membrane, since porin was not integrated when isolated outer mitochondrial membranes alone were incubated with the translation products. Porin in the cell-free translation products bound to the outside of the outer mitochondrial membrane when incubated with intact mitochondria at 0 degrees C for 5 min. When the incubation period at 0 degrees C was prolonged to 60 min, this porin was found in the inner membrane fraction, which contained monoamine oxidase, suggesting that porin might bind to a specific site on the outer membrane in contact or fused with the inner membrane (a so-called OM-IM site). This porin bound to the OM-IM site was integrated into the outer membrane when the membrane fraction was incubated at 30 degrees C for 60 min. These observations suggest that porin bound to the outside of the outer mitochondrial membrane is integrated into the outer membrane at the OM-IM site by some temperature-dependent process(es). 相似文献
24.
25.
26.
27.
28.
29.
Secretion of Recombinant Pediocin PA-1 by Bifidobacterium longum, Using the Signal Sequence for Bifidobacterial α-Amylase
下载免费PDF全文
![点击此处可从《Applied microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Gi-Seong Moon Yu-Ryang Pyun Myeong Soo Park Geun Eog Ji Wang June Kim 《Applied microbiology》2005,71(9):5630-5632
A recombinant DNA, encoding the chimeric protein of the signal sequence for bifidobacterial α-amylase mature pediocin PA-1, was introduced into Bifidobacterium longum MG1. Biologically active pediocin PA-1 was successfully secreted from the strain and showed bactericidal activity against Listeria monocytogenes and the same molecular mass as native pediocin PA-1. 相似文献
30.
Jin-Young Park 《Analytical biochemistry》2009,394(2):217-6489
Transglutaminases (TGs), a family of calcium-dependent transamidating enzymes, are involved in functions such as apoptosis and inflammation and play a role in autoimmune diseases and neurodegenerative disorders. In this study, we describe a novel array-based approach to rapidly determine in situ TG activity in human umbilical vein endothelial cells and J82 human bladder carcinoma cells. Amine arrays were fabricated by immobilizing 3-aminopropyltrimethoxysilane on glass slides. The assay was specific and highly reproducible. The average coefficient of variation betweens spots was 2.6% (n = 3 arrays), and the average correlation coefficients between arrays and between arrays/reactions were 0.998 and 0.976, respectively (n = 3 arrays). The assay was successfully applied to detect changes in TG activity induced by maitotoxin and to analyze inhibition of the TG activation with cystamine and monodansyl cadaverine. In addition, the assay demonstrated that intracellular reactive oxygen species regulate the maitotoxin-induced activation of TG. Thus, the array-based in situ TG activity assay constitutes a rapid and high-throughput approach to investigating the roles of TGs in cell signaling. 相似文献