全文获取类型
收费全文 | 141篇 |
免费 | 19篇 |
出版年
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2017年 | 1篇 |
2016年 | 9篇 |
2015年 | 4篇 |
2014年 | 11篇 |
2013年 | 8篇 |
2012年 | 10篇 |
2011年 | 12篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 9篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 11篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有160条查询结果,搜索用时 15 毫秒
21.
Sampa Santra Ashwini K. Sood Swapan K. Ghosh 《Cancer immunology, immunotherapy : CII》1999,48(8):421-429
Active specific immunotherapy of neoplastic diseases is an elusive goal. Using a murine B lymphoma 2C3, we showed that vaccination
with the killed tumor cells effectively induces protective immunity and a cytotoxic T cell (CTL) response. Similar protection,
however, is rarely observed in mice bearing live tumor cells. These animals usually succumb to the progressively growing tumor.
In this study, we inquired whether the splenic CTL induced during tumor progression in mice differ from those evoked by the
killed tumor cells. Here we demonstrate that the CTL generated following vaccination are significantly different from those
induced in the tumor-bearing hosts. Adding to the complexity, the CTL from the early tumor bearers also differ significantly
from those induced at the late stages. These differences are based on their cytotoxic activity, MHC allele specificity, mitogen
responsiveness, cytokine secretion profile and T cell receptor Vβ gene expression. The results clearly indicate that passive
immunization with killed tumor is most effective, possibly because the CTL induced are not subject to the same regulatory
pressure as those induced during active tumor growth. This decreasing effectiveness of CTL could be due to greater variability
in antigenic stimulus, less involvement of innate immunity, changes in cytokine milieu and/or costimulatory factors.
Received: 5 February 1999 / Accepted: 22 June 1999 相似文献
22.
A. Murugadoss Manoranjan Kar Renu Pasricha Arun Chattopadhyay 《Plasmonics (Norwell, Mass.)》2009,4(2):161-170
In this paper, we report the spontaneous formation of fibrous structures consisting of assemblies of Au–Ag core-shell nanoparticles
(NPs) from a solution consisting of Au–Ag core-shell NPs and l-ascorbic acid (AA). AA acted both as the reducing agent for the generation of NPs and also as the mediator for the formation
of fibers. The process of fiber formation involved three steps—reduction of HAuCl4 to Au NPs by AA, subsequent formation of Au–Ag core-shell NPs after addition of AgNO3, and spontaneous formation of fibers from the mixtures in water. It took typically about 30 days to form complete fibers
that are of lengths of several hundred micrometers to millimeters, although nanofibers started forming from the first day
of solution preparation. The width of each of these fibers was typically about 1–4 μm with length of each segment of fiber
bundle, on the order of 40 μm. Formation of fibers was also observed in absence of AgNO3. These fibers consisted of Au NPs and polymer of AA degradation products and were not electrically conducting. Also, low
concentrations of AgNO3 produced fibers with low electrical conductivity. However, it was observed that increase in the amount of AgNO3 leads to the formation of fibers that were electrically conducting with conductivity values in the range of metallic conductivity.
Spectroscopic and electron microscopic investigations were carried out to establish the formation of fibers. The details of
fiber formation mechanism under different conditions and electrical conductivities of the fibers are discussed in the article. 相似文献
23.
A unique Mycobacterium ESX-1 protein co-secretes with CFP-10/ESAT-6 and is necessary for inhibiting phagosome maturation 总被引:3,自引:0,他引:3
Xu J Laine O Masciocchi M Manoranjan J Smith J Du SJ Edwards N Zhu X Fenselau C Gao LY 《Molecular microbiology》2007,66(3):787-800
The ESX-1 secretion system plays a critical role in the virulence of Mycobacterium tuberculosis and M. marinum. To date, three proteins are known to be secreted by ESX-1 and necessary for virulence, two of which are CFP-10 and ESAT-6. The ESX-1 secretion and the virulence mechanisms are not well understood. In this study, we have examined the M. marinum secretomes and identified four proteins specific to ESX-1. Two of those are CFP-10 and ESAT-6, and the other two are novel: MM1553 (homologous to Rv3483c) and Mh3881c (homologous to Rv3881c). We have shown that Mh3881c, CFP-10 and ESAT-6 are co-dependent for secretion. Mh3881c is being cleaved at close to the C-terminus during secretion, and the C-terminal portion is critical to the co-dependent secretion, the ESAT-6 cellular levels, and interaction with ESAT-6. The co-dependent secretion is required for M. marinum intracellular growth in macrophages, where the Mh3881c C-terminal portion plays a critical role. The role of the co-dependent secretion in intracellular growth correlates with its role in inhibiting phagosome maturation. Both the secretion and the virulence defects of the Mh3881c mutant are complemented by Mh3881c or its M. tuberculosis homologue Rv3881c, suggesting that in M. tuberculosis, Rv3881c has similar functions. 相似文献
24.
Anindita Mitra Arnab Pramanik Subhas Chandra Santra Pradip Kumar Sen Joydeep Mukherjee 《World journal of microbiology & biotechnology》2011,27(7):1679-1688
No investigation has been done to identify ecological factors selecting for broad-spectrum antimicrobial activity of actinomycetes
in the estuaries. Previously, we established that, in the Sundarbans (the world’s largest tidal mangrove forest), high antagonistic potential (AP) sampling sites were influenced by tides, while
the low AP sites were not. We now report molecular phylogenetic analysis, morphological, physiological and biochemical characteristics
of actinomycetes of high AP sites. The effects of soil organic carbon, nitrogen and ionic content (which strongly influenced
AP) on the strength and spectrum of activity of the isolates were also studied in shake flasks. Molecular phylogenetic analysis
showed sequences of our strains to be 96–99% similar to the 16S rDNA sequences of Streptomyces. Results showed variation among sporophore sizes, ornamentation and number of spores. Jaccard’s similarity coefficients of
the isolates varied from 0.512 to 0.884 indicating disparity in the biochemical and physiological characteristics, possibly
due to spatial separation of the sampling sites. Top soil in the intertidal zone of estuaries is generated from settling and
consolidation of fluid mud and Streptomyces would be expected to produce broad-spectrum antimicrobials in such virgin soil. Isolates should be collected from the narrow
band between the mean high and low tide marks to maximize chances of finding broad-spectrum activity. Considering the study
on nutritional requirements vis-à-vis the field studies, it was concluded that results of this investigation corroborated
the field observations where soil nitrogen, rather than organic carbon or ionic concentration, played a major role in determining
the antimicrobial spectrum. 相似文献
25.
The viability of metacercariae of Fasciola gigantica was tested by in vitro and in vivo methods. In vitro testing was based upon the motility of juvenile flukes within the inner cyst as examined under the light microscope. In vivo testing was undertaken through experimental infections of rabbits (two groups) and natural definitive hosts, lambs (one group). In the first group, out of six rabbits each given 25 metacercariae, worm establishment only took place in one rabbit with a single fluke recovery on 60 days post infection. In the second group of six rabbits each given 200 metacercariae, five were infected, with two or three flukes per host. All the lambs given 250 metacercariae became infected showing prevalences of 7.2-40% in comparison with rabbits in which low prevalences (0-4%) were recorded. The results indicated that even viable metacercariae which were already tested in vitro could not readily establish in rabbits. Such variability in worm establishment suggests that immunological and chemotherapeutic studies in rabbits infected with F. gigantica are likely to be unreliable. 相似文献
26.
Santosh G. Rajput Dipak K. Santra James Schnable 《Molecular breeding : new strategies in plant improvement》2016,36(4):37
Proso millet (Panicum miliaceum L.) is the cereal crop with the low water requirement and increasingly being used for human consumption. It is the most common rotational crop within wheat-based dryland production systems in the semiarid High Plains of the USA. However, there is no published genetic map for this species, which prevents the identification of quantitative trait loci (QTL). The objectives of the present study were (1) construction of a genetic linkage map and (2) identification of DNA markers linked to QTLs for morpho-agronomic traits. A total of 93 recombinant inbred lines derived from a single F1 (“Huntsman” × “Minsum”) were genotyped with GBS-SNP markers and phenotyped for nine morpho-agronomic traits in the field during 2013 and 2014 at Scottsbluff and Sidney, NE. IciMapping v.4.0.6.0 was used for constructing a genetic linkage map and mapping QTL. The RILs exhibited significant variation for a wide range of traits, and several traits showed evidence of genotype × environment interactions. A total of 833 GBS-SNP markers formed 18 major and 84 minor linkage groups, whereas 519 markers remained ungrouped. A total of 117 GBS-SNP markers were distributed on the 18 major linkage groups spanning a genome length of 2137 cM of proso millet with an average distance of 18 cM between markers. The length and number of markers in each of the 18 major linkage groups ranged from 54.6 to 236 cM and 4 to 12, respectively. A total of 18 QTLs for eight morpho-agronomic traits were detected on 14 linkage groups, each of which explained 13.2–34.7 % phenotypic variance. DNA markers flanking the QTLs were identified, which will aid in marker-assisted selection of these traits. To our knowledge, this is the first genetic linkage map and QTL mapping in proso millet, which will support further genetic analysis and genomics-assisted genetic improvement of this crop. 相似文献
27.
Navid Madani Amy M. Princiotto David Easterhoff Todd Bradley Kan Luo Wilton B. Williams Hua-Xin Liao M. Anthony Moody Ganesh E. Phad Néstor Vázquez Bernat Bruno Melillo Sampa Santra Amos B. Smith III Gunilla B. Karlsson Hedestam Barton Haynes Joseph Sodroski 《Journal of virology》2016,90(10):5031-5046
28.
Genotyping of Novel SNPs in BMPR1B,BMP15, and GDF9 Genes for Association with Prolificacy in Seven Indian Goat Breeds 总被引:1,自引:0,他引:1
Sonika Ahlawat Rekha Sharma Manoranjan Roy Sanjay Mandakmale Ved Prakash M S Tantia 《Animal biotechnology》2016,27(3):199-207
Goats form the backbone of rural livelihood and financial security systems in India but their population is showing decreasing trend. Improvement of reproductive traits such as prolificacy offers a solution to stabilize the decreasing goat population and to meet the nutritional needs of growing human population. In the present study, six novel SNPs in three candidate genes for prolificacy (BMPR1B, BMP15, and GDF9) were genotyped in seven breeds of Indian goats to evaluate their association with litter size. Tetra primer ARMS-PCR and PCR-RFLP based protocols were developed for genotyping six novel SNPs, namely, T(-242)C in BMPR1B; G735A and C808G in BMP15; and C818T, A959C, and G1189A in GDF9 gene. The effect of breed was highly significant (p ≤ 0.01) on litter size but the effect of genotype was nonsignificant. The effect of parity on litter size was also significant in the prolific Black Bengal breed. The litter size differences observed between breeds are attributed to breed differences. Novel mutations observed at different loci in GDF9, BMP15, and BMPR1B genes do not contribute to the reproductive capability of the investigated breeds. Further studies with more number of breeds and animals exploring association of these novel SNPs with reproductive traits may be fruitful. 相似文献
29.
The Belousov-Zhabotinskii reaction has been modelled by Field and Noyes [5] as a pair of nonlinear parabolic equations. Previous studies of these, both theoretical and numerical, have assumed wave solutions travelling with constant velocity leading to a simplification of the mathematical model in the form of a system of ordinary differential equations. In the present study a finite element Galerkin method is used directly on the original parabolic system for a range of parameter values. 相似文献
30.