全文获取类型
收费全文 | 532篇 |
免费 | 72篇 |
国内免费 | 6篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 20篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 8篇 |
2016年 | 16篇 |
2015年 | 26篇 |
2014年 | 25篇 |
2013年 | 39篇 |
2012年 | 40篇 |
2011年 | 43篇 |
2010年 | 31篇 |
2009年 | 31篇 |
2008年 | 36篇 |
2007年 | 35篇 |
2006年 | 20篇 |
2005年 | 17篇 |
2004年 | 16篇 |
2003年 | 15篇 |
2002年 | 10篇 |
2001年 | 11篇 |
2000年 | 15篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有610条查询结果,搜索用时 15 毫秒
81.
This article serves as a demonstration of how certain models of literary analysis, used to theorize and analyze fiction and
narrative, can also be applied to scientific communication in such a manner as to promote the accessibility of science to
the general public and a greater awareness of the methodology used in making scientific discovery. The approach of this article
is based on the assumption that the principles of structuralism and semiotics can provide plausible explanations for the divide
between the reception of science and literature. We provide a semiotic analysis of a scientific article that has had significant
impact in the field of molecular biology with profound medical implications. Furthermore, we show how the structural and semiotic
characteristics of literary texts are also evident in the scientific papers, and we address how these characteristics can
be applied to scientific prose in order to propose a model of scientific communication that reaches the public. By applying
this theoretical framework to the analysis of both scientific and literary communication, we establish parallels between primary
scientific texts and literary prose. 相似文献
82.
83.
Phosphomannose isomerase (PMI) plays a pivotal role in biosynthesis of GDP-mannose, an important precursor of many polysaccharides. We demonstrate in this study that Pseudomonas aeruginosa pslB encodes a protein with GDP-mannose pyrophosphorylase/PMI dual activities. The PMI activity is Co2+-dependent and could be inhibited by GDP-mannose in a competitive manner. Furthermore, the activity could be inactivated by 2,3-butanedione suggesting the presence of a catalytic Arg residue. Site-specific mutations at R373, R472, R479, E410, H411, N433 and E458 increase the KM approximately 8-20-fold. The PMI activity of PslB was completely diminished with a R408K or R408A, reflecting the importance of this residue in catalysis. Overall, these results provide a basis for understanding the catalytic mechanism of PMI. 相似文献
84.
Antimicrobial activity of saponin fractions of the leaves of Gymnema sylvestre and Eclipta prostrata
Venkatesan Gopiesh khanna Krishnan Kannabiran 《World journal of microbiology & biotechnology》2008,24(11):2737-2740
The antimicrobial activity of saponin fractions from the leaves of Gymnema sylvestre and Eclipta prostrata was evaluated against pathogenic bacteria and fungi in an in vitro condition. A series of concentrations of crude and pure
saponin fractions were tested for antimicrobial activity by zone of inhibition method. The pure saponin fractions were found
to be more effective against tested bacterial pathogens when compared to crude saponin fractions. The minimum inhibitory concentration
(MIC) exhibited by the pure saponin fraction of G. sylvestre was found to be in the range of 600–1,200 mg/l against bacterial strains and 1,400 mg/l for fungal isolates. In the case
of E. prostrata, the range was 1,000–1,200 mg/l for bacteria and 1,400 mg/l for fungal isolates. The susceptibility of bacterial pathogens
for saponin fractions was in the order of P. aeruginosa, E. coli, S. typhi, K. pneumoniae, P. mirablis, S. aureus and for fungal pathogens A. fumigatus followed by A. niger and A. flavus. Whereas, A. niger was more susceptible to inhibition by E. prostrata saponin fractions, followed by A. flavus and A. fumigatus. The antimicrobial potential of saponin fractions was compared with antibiotics, Chloramphenicol and Amphotericin-B with
respect to bacteria and fungi. The present study suggests that the saponin fractions G. sylvestre and E. prostrata possess significant antibacterial and antifungal activity. Our results further suggest that saponins of G. sylvestre and E. prostrata can be used as a potential fungicide against pathogenic fungi. 相似文献
85.
Vimaleswaran KS Radha V Ramya K Babu HN Savitha N Roopa V Monalisa D Deepa R Ghosh S Majumder PP Rao MR Mohan V 《Human genetics》2008,123(6):599-605
Adiponectin is an adipose tissue specific protein that is decreased in subjects with obesity and type 2 diabetes. The objective
of the present study was to examine whether variants in the regulatory regions of the adiponectin gene contribute to type
2 diabetes in Asian Indians. The study comprised of 2,000 normal glucose tolerant (NGT) and 2,000 type 2 diabetic, unrelated
subjects randomly selected from the Chennai Urban Rural Epidemiology Study (CURES), in southern India. Fasting serum adiponectin
levels were measured by radioimmunoassay. We identified two proximal promoter SNPs (−11377C→G and −11282T→C), one intronic
SNP (+10211T→G) and one exonic SNP (+45T→G) by SSCP and direct sequencing in a pilot study (n = 500). The +10211T→G SNP alone was genotyped using PCR-RFLP in 4,000 study subjects. Logistic regression analysis revealed
that subjects with TG genotype of +10211T→G had significantly higher risk for diabetes compared to TT genotype [Odds ratio
1.28; 95% Confidence Interval (CI) 1.07–1.54; P = 0.008]. However, no association with diabetes was observed with GG genotype (P = 0.22). Stratification of the study subjects based on BMI showed that the odds ratio for obesity for the TG genotype was
1.53 (95%CI 1.3–1.8; P < 10−7) and that for GG genotype, 2.10 (95% CI 1.3–3.3; P = 0.002). Among NGT subjects, the mean serum adiponectin levels were significantly lower among the GG (P = 0.007) and TG (P = 0.001) genotypes compared to TT genotype. Among Asian Indians there is an association of +10211T→G polymorphism in the
first intron of the adiponectin gene with type 2 diabetes, obesity and hypoadiponectinemia. 相似文献
86.
87.
Respiratory syncytial virus fusion glycoprotein: nucleotide sequence of mRNA, identification of cleavage activation site and amino acid sequence of N-terminus of F1 subunit. 总被引:14,自引:2,他引:12
下载免费PDF全文
![点击此处可从《Nucleic acids research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
N Elango M Satake J E Coligan E Norrby E Camargo S Venkatesan 《Nucleic acids research》1985,13(5):1559-1574
The amino acid sequence of respiratory syncytial virus fusion protein (Fo) was deduced from the sequence of a partial cDNA clone of mRNA and from the 5' mRNA sequence obtained by primer extension and dideoxysequencing. The encoded protein of 574 amino acids is extremely hydrophobic and has a molecular weight of 63371 daltons. The site of proteolytic cleavage within this protein was accurately mapped by determining a partial amino acid sequence of the N-terminus of the larger subunit (F1) purified by radioimmunoprecipitation using monoclonal antibodies. Alignment of the N-terminus of the F1 subunit within the deduced amino acid sequence of Fo permitted us to identify a sequence of lys-lys-arg-lys-arg-arg at the C-terminus of the smaller N-terminal F2 subunit that appears to represent the cleavage/activation domain. Five potential sites of glycosylation, four within the F2 subunit, were also identified. Three extremely hydrophobic domains are present in the protein; a) the N-terminal signal sequence, b) the N-terminus of the F1 subunit that is analogous to the N-terminus of the paramyxovirus F1 subunit and the HA2 subunit of influenza virus hemagglutinin, and c) the putative membrane anchorage domain near the C-terminus of F1. 相似文献
88.
89.
90.