全文获取类型
收费全文 | 249篇 |
免费 | 12篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 15篇 |
2014年 | 19篇 |
2013年 | 14篇 |
2012年 | 31篇 |
2011年 | 18篇 |
2010年 | 16篇 |
2009年 | 11篇 |
2008年 | 10篇 |
2007年 | 13篇 |
2006年 | 14篇 |
2005年 | 13篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1988年 | 2篇 |
1985年 | 1篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有261条查询结果,搜索用时 31 毫秒
101.
M. Ravishankar Ram Khean Lee Goh Alex Hwong Ruey Leow Bee Hoon Poh Mun Fai Loke Richard Harrison Esaki M. Shankar Jamuna Vadivelu 《PloS one》2015,10(11)
Helicobacter pylori (H. pylori) -induced gastric inflammation impacts the functions of leptin- and ghrelin-producing cells in the gastroduodenum. Inflammation resulting from H. pylori sensing via Toll-like receptors (TLRs) and the associated downstream signaling largely remain ambiguous. Here, we investigated the role of gut hormones, pro-inflammatory cytokines and single nucleotide polymorphisms (SNPs) associated with TLR 4p14 in H. pylori disease in 30 subjects with non-ulcer dyspepsia (NUD), 40 with peptic ulcer disease (PUD) and 15 with gastric cancer (GC) subjects positive and negative for H. pylori infection. The level of pro-inflammatory cytokines was directly proportional to the severity of gastritis, and disease status influenced the levels of gut hormones and pro-inflammatory cytokines. TLR-1 SNPs rs4833095 and TLR-10 SNPs rs10004195 and were directly associated with H. pylori disease, and were up-regulated in the presence of H. pylori in a genotype-independent manner. We concluded that TLR-1 rs4833095 and TLR10 rs10004195 confer susceptibility to development of gastroduodenal disease, especially GC in H.pylori disease. 相似文献
102.
103.
Abstract Genetic transfer of both auxotrophic and catabolic markers was detected in filter matings of mutant strains of Pseudomonas alcaligenes NCIB 9867. Bidirectional transfer of auxotrophic markers was demonstrated in most of the crosses. Strains could either act as donors or recipients. Polarized transfer of auxotrophic markers was observed in some crosses. There was low co-inheritance of both 2,5X+ catabolic marker and auxotrophic markers. No evidence could be presented indicating the involvement of the indigenous 33-kb plasmid in the genetic transfer process. Partial sensitivity to DNase was observed in some of the crosses. Maximum frequency of recombinant formation obtained with mating cultures from stationary growth phase suggested an influence of physiological states on genetic transfer. As transfer did not appear to be due to classical transformation or to be plasmid-mediated, the likely mechanism could involve the release of DNA upon intimate cell-to-cell contact. The gene transfer system may be useful for linkage analysis of closely linked genes. 相似文献
104.
Current viral gene delivery vectors for gene therapy are inefficient due to short-lived transgene expression attributed to the cytosine-phosphate-guanine (CpG) motifs in the transgene. Here we assessed the effects of CpG motif reduction in lentiviral (LV) gene delivery context on the level and duration of reporter gene expression in Chinese Hamster Ovary (CHO) cells, Human Immortalized Myelogenous Leukemia (K562) cells and hematopoietic stem cells (HSCs). The cells were transduced with LV carrying Zero-CpG green fluorescent protein (ZGFP) reporter gene, LV/CMV/ZGFP. The GFP expression was compared to its non CpG-depleted GFP reporter gene LV (LV/CMV/GFP) counterpart. The LV/CMV/ZGFP exhibited prolonged transgene expression in CHO cells and HSCs up to 10 days and 14 days, in the respective cells. This effect was not seen in the transduced K562 cells, which may be due to the DNA hypomethylation status of the cancer cell line. Transgene copy number analysis verified that the GFP expression was not from pseudo-transduction and the transgene remained in the genome of the cells throughout the period of the study. The modest positive effects from the LV/CMV/ZGFP suggest that the reduction of CpG in the LV construct was not substantial to generate higher and more prolonged transgene expression. 相似文献
105.
It has been previously established that living cells, including mesenchymal stem cells, stiffen in response to elevation of substrate stiffness. This stiffening is largely attributed to the elevation of the tractions at the cell base that is associated with increases in cell spreading on more-rigid substrates. We show here, surprisingly, that mouse embryonic stem cells (ESCs) do not stiffen when substrate stiffness increases. As shown recently, these cells do not increase spreading on more-rigid substrates either. However, these ESCs do increase their basal tractions as substrate stiffness increases. We conclude that these ESCs exhibit mechanical behaviors distinct from those of mesenchymal stem cells and of terminally differentiated cells, and decouple its apical cell stiffness from its basal tractional stresses during the substrate rigidity response. 相似文献
106.
The muscular layers within the walls of the gastrointestinal tract contain two distinct cell types, the interstitial cells of Cajal and smooth muscle cells, which together produce rhythmic depolarizations known as slow waves. The bidomain model of tissue-level electrical activity consists of single intracellular and extracellular domains separated by an intervening membrane at all points in space and is therefore unable to adequately describe the presence of two distinct cell types in its conventional form. Here, an extension to the bidomain framework is presented whereby multiple interconnected cell types can be incorporated. Although the derivation is focused on the interactions of the interstitial cells of Cajal and smooth muscle cells, the conceptual framework can be more generally applied. Simulations demonstrating the feasibility of the proposed model are also presented. 相似文献
107.
108.
109.
Pejman Azadi Ntui Valentaine Otang Dong Poh Chin Ikuo Nakamura Masaki Fujisawa Hisashi Harada Norihiko Misawa Masahiro Mii 《Plant biotechnology reports》2010,4(4):269-280
Lilium × formolongi was genetically engineered by Agrobacterium-mediated transformation with the plasmid pCrtZW-N8idi-crtEBIY, which contains seven enzyme genes under the regulation of
the CaMV 35S promoter. In the transformants, ketocarotenoids were detected in both calli and leaves, which showed a strong
orange color. In transgenic calli, the total amount of carotenoids [133.3 μg/g fresh weight (FW)] was 26.1-fold higher than
in wild-type calli. The chlorophyll content and photosynthetic efficiency in transgenic orange plantlets were significantly
lowered; however, after several months of subculture, they had turned into plantlets with green leaves that showed significant
increases in chlorophyll and photosynthetic efficiency. The total carotenoid contents in leaves of transgenic orange and green
plantlets were quantified at 102.9 and 135.2 μg/g FW, respectively, corresponding to 5.6- and 7.4-fold increases over the
levels in the wild-type. Ketocarotenoids such as echinenone, canthaxanthin, 3′-hydroxyechinenone, 3-hydroxyechinenone, and
astaxanthin were detected in both transgenic calli and orange leaves. A significant change in the type and composition of
ketocarotenoids was observed during the transition from orange transgenic plantlets to green plantlets. Although 3′-hydroxyechinenone,
3-hydroxyechinenone, astaxanthin, and adonirubin were absent, and echinenone and canthaxanthin were present at lower levels,
interestingly, the upregulation of carotenoid biosynthesis led to an increase in the total carotenoid concentration (+31.4%)
in leaves of the transgenic green plantlets. 相似文献
110.
Hirutani Sakiko Shimomae Kazuki Yaguchi Akira Chin Dong Poh Mii Masahiro Igawa Tomoko 《Plant Cell, Tissue and Organ Culture》2020,142(2):435-440
Plant Cell, Tissue and Organ Culture (PCTOC) - Begonia semperflorens-cultorum, known as wax begonia, is one of the most popular Begonia species in which variable commercial cultivars have been... 相似文献