全文获取类型
收费全文 | 498篇 |
免费 | 40篇 |
国内免费 | 2篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 21篇 |
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 14篇 |
2017年 | 11篇 |
2016年 | 18篇 |
2015年 | 26篇 |
2014年 | 22篇 |
2013年 | 30篇 |
2012年 | 49篇 |
2011年 | 46篇 |
2010年 | 26篇 |
2009年 | 15篇 |
2008年 | 26篇 |
2007年 | 25篇 |
2006年 | 28篇 |
2005年 | 29篇 |
2004年 | 27篇 |
2003年 | 7篇 |
2002年 | 14篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有540条查询结果,搜索用时 31 毫秒
531.
Chee Sian Kuan Su Mei Yew Yue Fen Toh Chai Ling Chan Yun Fong Ngeow Kok Wei Lee Shiang Ling Na Wai-Yan Yee Chee-Choong Hoh Kee Peng Ng 《DNA research》2015,22(3):219-232
Bipolaris papendorfii has been reported as a fungal plant pathogen that rarely causes opportunistic infection in humans. Secondary metabolites isolated from this fungus possess medicinal and anticancer properties. However, its genetic fundamental and basic biology are largely unknown. In this study, we report the first draft genome sequence of B. papendorfii UM 226 isolated from the skin scraping of a patient. The assembled 33.4 Mb genome encodes 11,015 putative coding DNA sequences, of which, 2.49% are predicted transposable elements. Multilocus phylogenetic and phylogenomic analyses showed B. papendorfii UM 226 clustering with Curvularia species, apart from other plant pathogenic Bipolaris species. Its genomic features suggest that it is a heterothallic fungus with a putative unique gene encoding the LysM-containing protein which might be involved in fungal virulence on host plants, as well as a wide array of enzymes involved in carbohydrate metabolism, degradation of polysaccharides and lignin in the plant cell wall, secondary metabolite biosynthesis (including dimethylallyl tryptophan synthase, non-ribosomal peptide synthetase, polyketide synthase), the terpenoid pathway and the caffeine metabolism. This first genomic characterization of B. papendorfii provides the basis for further studies on its biology, pathogenicity and medicinal potential. 相似文献
532.
Anthony T. Tan Martin Linster Chee Wah Tan Nina Le Bert Wan Ni Chia Kamini Kunasegaran Yan Zhuang Christine Y.L. Tham Adeline Chia Gavin J.D. Smith Barnaby Young Shirin Kalimuddin Jenny G.H. Low David Lye Lin-Fa Wang Antonio Bertoletti 《Cell reports》2021,34(6):108728
- Download : Download high-res image (224KB)
- Download : Download full-size image
533.
Chee Han Lim Sabrina Voedisch Benjamin Wahl Syed Fazle Rouf Robert Geffers Mikael Rhen Oliver Pabst 《PLoS pathogens》2014,10(7)
Vaccination represents an important instrument to control typhoid fever in humans and protects mice from lethal infection with mouse pathogenic serovars of Salmonella species. Mixed infections with tagged Salmonella can be used in combination with probabilistic models to describe the dynamics of the infection process. Here we used mixed oral infections with tagged Salmonella strains to identify bottlenecks in the infection process in naïve and vaccinated mice. We established a next generation sequencing based method to characterize the composition of tagged Salmonella strains which offers a fast and reliable method to characterise the composition of genome-tagged Salmonella strains. We show that initial colonization of Salmonella was distinguished by a non-Darwinian selection of few bacteria setting up the infection independently in gut associated lymphoid tissue and systemic compartments. Colonization of Peyer''s patches fuels the sustained spread of bacteria into mesenteric lymph nodes via dendritic cells. In contrast, infection of liver and spleen originated from an independent pool of bacteria. Vaccination only moderately reduced invasion of Peyer''s patches but potently uncoupled bacterial populations present in different systemic compartments. Our data indicate that vaccination differentially skews the capacity of Salmonella to colonize systemic and gut immune compartments and provide a framework for the further dissection of infection dynamics. 相似文献
534.
This study indicates that crystalloid (Sacks') and colloid (modified silica gel fraction of plasma, MSGF) hyperosmolar solutions are edequate means to preserve whole pancreas allografts under hypothermia (4 to 7 °C) for 24 hr. These groups of preserved canine pancreas allografts survived as long as the fresh transplanted pancreas. However, when the preservation was extended to 48 hr, the crystalloid hyperosmolar solution did not protect the pancreas allografts, but the colloid hyperosmolar solution gave similar results to fresh pancreas allografts. 相似文献
535.
Hong Hao Chan Yong Qi Leong Shee Man Voon Meng Liy Pan Chee Onn Leong Chooi Ling Lim Rhun Yian Koh 《Reports of Biochemistry & Molecular Biology》2021,9(4):417
Background:Alzheimer’s disease (AD) is a neurodegenerative disorder that causes cognitive dysfunction. Previous studies have suggested that amyloid plaques, mainly comprising of amyloid-beta peptides, play a pivotal role in AD pathophysiology. This study focuses on the evaluation of the effects of amyloid precursor protein (APP) overexpression on NF-κB, Rho-GTPase and Bcl-2 mediated pro-apoptotic pathways in neuronal cells. Methods:A lentiviral transduction system was used to generate SH-SY5Y cells overexpressing APP. Immunoblotting was conducted to determine expression levels of NF-κB, Rho-GTPase, and Bcl-2 family proteins in the APP overexpressed cells.Results:In the NF-κB signaling pathway, APP-overexpressing SH-SY5Y cells showed that there was a reduction of p-NF-κB (p< 0.05) and IKKα. Subsequently, there was upregulation of protein expression of NF-Κb, IKKβ and IκBα. On the other hand, protein expression of RhoC (p< 0.05) and Rac1/2/3 was upregulated as compared to the control group. Meanwhile, a decrease in RhoA, Cdc42 (p< 0.05) and p-Rac1/cdc42 protein levels was observed in the APP-overexpressed group. Lastly, in the pro-apoptotic pathway, the expression of Bcl-2, Bid, Bok and Puma (p< 0.05) was up regulated in the APP-overexpressed group. Downregulation of Bad and Bim expression was observed in the APP-overexpressed as compared to the control group, and Bax expression remained unchanged in the APP-overexpressed group.Conclusion:APP overexpression regulated signaling in the NF-κB, Rho-GTPase and Bcl-2 family pathways in neuronal cells, suggesting that these are involved in promoting neuronal survival and modulating synaptic plasticity in AD. However, further studies are essential to elucidate the APP-mediated mechanism of action.Key Words: Alzheimer’s disease, Amyloid precursor protein, Bcl-2 family proteins, NF-κB, Rho-GTPase 相似文献
536.
Present study aims to optimize the production of starch and total carbohydrates from Arthrospira platensis. Growing concerns toward unprecedented environmental issues associated with plastic pollution has created a tremendous impetus to develop new biomaterials for the production of bioplastic. Starch-based biopolymers from algae serve as sustainable feedstock for thermoplastic starch production due to their abundant availability and low cost. A. platensis was cultivated in Zarrouk's medium at 32 ± 1°C and exposed to red light with a photoperiod of 12:12 hr light/dark. Growth kinetics studies showed that the maximum specific growth rate (μmax) obtained was 0.059 day−1 with the doubling time (td) of 11.748 days. Subsequently, Zarrouk's medium with different concentrations of sulfur, phosphorus and nitrogen was prepared to establish the nutrient-limiting conditions to enhance the accumulation of starch and total carbohydrates. In this study, the highest starch accumulated was 6.406 ± 0.622 mg L−1 under optimized phosphorus limitation (0.025 g L−1) conditions. Nitrogen limitation (0.250 g L−1) results demonstrated significant influenced (p < 0.05) on total carbohydrates (67.573 ± 2.893 mg L−1) accumulation in A. platensis. The starch accumulation in A. platensis was significantly affected (p < 0.05) by phosphorus limitation (0.0025 g L−1). Subsequently, the optimized phosphorus concentration was coupled with mixotrophic cultivation to further enhance the starch accumulation. The results obtained indicated that, the starch (11.426 ± 0.314 mg L−1) and carbohydrates (43.053 ± 2.986 mg L−1) concentration obtained was significantly high (p < 0.05) under mixotrophic cultivation. Therefore, it shown that nutrient limitation and mixotrophic cultivation are viable strategies to enhance the accumulation of starch and total carbohydrates in A. platensis. 相似文献
537.
Yuan Yang Wen Li Qinge Zhang Ling Zhang Teris Cheung Chee H Ng Yu-Tao Xiang 《International journal of biological sciences》2021,17(6):1443
The coronavirus disease-19 (COVID-19) has spread throughout the world, affecting many vulnerable populations including patients with severe mental illness (SMI). Recent studies have found that patients with SMI compared to the general population could have a greater risk of morbidity and mortality from COVID-19 due to cognitive impairment, poor awareness of risk, and difficulties in complying with infection control measures. Although some researchers have suggested that patients with SMI should be prioritized for COVID-19 vaccination to reduce the risk of infection, this issue remains controversial. 相似文献
538.
539.
540.
Hydrobiologia - Cyanobacteria are oxygenic photosynthetic organisms that are prevalent in freshwater and marine ecosystems. A proportion of the cyanobacteria in a given locality are known to be... 相似文献