全文获取类型
收费全文 | 1051篇 |
免费 | 108篇 |
国内免费 | 1篇 |
出版年
2023年 | 10篇 |
2022年 | 14篇 |
2021年 | 48篇 |
2020年 | 23篇 |
2019年 | 18篇 |
2018年 | 41篇 |
2017年 | 30篇 |
2016年 | 63篇 |
2015年 | 41篇 |
2014年 | 66篇 |
2013年 | 79篇 |
2012年 | 74篇 |
2011年 | 77篇 |
2010年 | 43篇 |
2009年 | 43篇 |
2008年 | 51篇 |
2007年 | 44篇 |
2006年 | 56篇 |
2005年 | 35篇 |
2004年 | 41篇 |
2003年 | 37篇 |
2002年 | 20篇 |
2001年 | 11篇 |
2000年 | 13篇 |
1999年 | 12篇 |
1998年 | 7篇 |
1996年 | 8篇 |
1994年 | 6篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 5篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1983年 | 8篇 |
1982年 | 3篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 6篇 |
1970年 | 6篇 |
1969年 | 12篇 |
1968年 | 6篇 |
1967年 | 3篇 |
排序方式: 共有1160条查询结果,搜索用时 15 毫秒
971.
Bryzgalova G Effendic S Khan A Rehnmark S Barbounis P Boulet J Dong G Singh R Shapses S Malm J Webb P Baxter JD Grover GJ 《The Journal of steroid biochemistry and molecular biology》2008,111(3-5):262-267
Selective thyroid hormone receptor subtype-beta (TRbeta) agonists have received attention as potential treatments for hypercholesterolemia and obesity, but have received less attention as treatments for diabetes, partly because this condition is not improved in thyroid hormone excess states. The TRbeta selective agonist KB-141 induces 5-10% increases in metabolic rate and lowering of plasma cholesterol levels without tachycardia in lean rats, unlike the major active thyroid hormone, T(3). In the current study, we determined whether KB-141 promotes weight loss in obese animals and whether it exhibits anti-diabetogenic effects. Body weight, adiposity (DEXA), and lipid levels were examined following p.o. administration of KB-141 to obese Zucker fa/fa rats at 0.00547-0.547mg/kg/day for 21 days, and in ob/ob mice at 0.5mg/kg/day KB-141 for 7 days. In rats, KB-141 reduced body weight by 6 and 8%, respectively, at 0.167 and 0.0547mg/kg/day without tachycardia and adiposity was reduced at 0.167mg/kg/day (5-6%). In ob/ob mice, KB-141 lowered serum cholesterol (35%), triacylglycerols (35%) and both serum and hepatic free fatty acids (18-20%) without tachycardia. Treatment of ob/ob mice with KB-141 (0.0547 or 0.328mg/kg/day over 2 weeks) improved glucose tolerance and insulin sensitivity in a dose-dependent manner with no effect on heart rate. Thus, KB-141 elicits anti-obesity, lipid lowering and anti-diabetic effects without tachycardia suggesting that selective TRbeta activation may be useful strategy to attenuate features of the metabolic syndrome. 相似文献
972.
973.
974.
Mini-scale Genomic DNA Extraction from Cotton 总被引:8,自引:1,他引:7
Chaudhry Bushra Yasmin Afshan Husnain Tayyib Riazuddin S. 《Plant Molecular Biology Reporter》1999,17(3):280-280
Large amounts of polyphenolics in cotton leaves make it difficult to obtain high-quality genomic DNA during extraction. A procedure to isolate nuclear DNA from local cotton leaves (gossypium hirsutum, MNH93, CIM443, FH672) was therefore developed. It consists of rapid isolation of stable nuclei, which hinders covalent interactions with phenolics, followed by DNA extraction. The yield and quality of the resulting DNA is satisfactory and the protocol can be scaled up or down according to sample size. It is suitable for PCR and the restriction enzyme digestion needed for Southern and RFLP analysis. 相似文献
975.
The aim of this study was to evaluate the enzymatic action of partially purified bitter gourd peroxidase for the degradation/decolorization of complex aromatic structures. Twenty-one dyes, with a wide spectrum of chemical groups, currently being used by the textile and other important industries have been selected for the study. Here, for the first time we have shown peroxidases from Momordica charantia (300 EU/gm of vegetable) to be highly effective in decolorizing industrially important dyes. Dye solutions, containing 50-200 mg dye/l, were used for the treatment with bitter gourd peroxidase (specific activity of 99.0 EU/mg protein). M. charantia peroxidases were able to decolorize most of the textile dyes by forming insoluble precipitate. When the textile dyes were treated with increasing concentration of enzyme, it was observed that greater fraction of the color was removed but four out of eight reactive dyes were recalcitrant to decolorization by bitter gourd peroxidase. Step-wise addition of enzyme to the decolorizing reaction mixture at the interval of 1h further enhanced the dye decolorization. The rate of decolorization was enhanced when the dyes were incubated with fixed quantity of enzyme for increasing times. Decolorization of non-textile dyes resulted in the degradation and removal of dyes from the solution without any precipitate formation. Decolorization rate was drastically increased when the textile and other industrially important non-textile dyes were treated with bitter gourd peroxidase in presence of 1.0 mM 1-hydroxybenzotriazole. Complex mixtures of dyes were prepared by taking three to four reactive textile and non-textile dyes in equal proportions. Each mixture was decolorized by more than 80% when treated with the enzyme in presence of 1.0 mM 1-hydroxybenzotriazole. Our data suggest that the peroxidase/mediator system is an effective biocatalyst for the treatment of effluents containing recalcitrant dyes from textile, dye manufacturing, dyeing and printing industries. 相似文献
976.
977.
Goh BH Efendić S Khan A Portwood N 《Biochemical and biophysical research communications》2003,307(4):935-941
Glucose-6-phosphatase (G6Pase) is a multicomponent enzyme system which regulates the catalysis of glucose-6-phosphate (G6P) to glucose and inorganic phosphate. G6Pase can antagonize glucose phosphorylation, a step prerequisite in the regulation of insulin secretion from pancreatic beta cells, and G6Pase activity is increased in islets isolated from animal models of type II diabetes. Using RT-PCR with hepatic G6Pase catalytic subunit primers, we demonstrate that the sizes of amplified products from ob/ob mouse islets are identical to those from liver cDNA. This was confirmed by PCR-based cloning and sequencing of the hepatic G6Pase catalytic subunit open reading frame from islet cDNA. The expression in islets of the G6P transporter, G6PT1, was also demonstrated, suggesting that all of the identified hepatic G6Pase system genes are expressed in pancreatic islets. Finally, the expression of islet-specific G6Pase-related protein (IGRP) in pancreatic islets was confirmed and its expression in liver was also observed. 相似文献
978.
Williams P Chaudhry Y Goodfellow IG Billington J Powell R Spiller OB Evans DJ Lea S 《The Journal of biological chemistry》2003,278(12):10691-10696
Decay-accelerating factor (CD55), a regulator of the alternative and classical pathways of complement activation, is expressed on all serum-exposed cells. It is used by pathogens, including many enteroviruses and uropathogenic Escherichia coli, as a receptor prior to infection. We describe the x-ray structure of a pathogen-binding fragment of human CD55 at 1.7 A resolution containing two of the three domains required for regulation of human complement. We have used mutagenesis to map biological functions onto the molecule; decay-accelerating activity maps to a single face of the molecule, whereas bacterial and viral pathogens recognize a variety of different sites on CD55. 相似文献
979.
Kaderbhai MA Hopper DJ Akhtar KM Abbas SK Kaderbhai NN 《Applied and environmental microbiology》2003,69(8):4727-4731
We have cloned, sequenced, and heterologously expressed a periplasmic cytochrome c from a lupanine-utilizing Pseudomonas putida strain. Aerobic batch cultivation of Escherichia coli TB1 harboring the cytochrome c gene placed downstream of the lac promoter in pUC9 vector resulted in significant production of the holo-cytochrome c in the periplasm ( approximately 4 mg of hemoprotein/liter of culture). The recombinant cytochrome c was purified to homogeneity and was found to be functional in accepting electrons from lupanine hydroxylase while catalyzing hydroxylation of lupanine. Comparison of the N-terminal amino acid sequence of the isolated cytochrome c with that deduced from the DNA sequence indicated that the signal sequence was processed at the bond position predicted by the SigPep program. The molecular size of the cytochrome c determined by electrospray mass spectrometry (9,595) was in precise agreement with that predicted from the nucleotide sequence. 相似文献
980.
Identification of microcephalin,a protein implicated in determining the size of the human brain 总被引:4,自引:0,他引:4 下载免费PDF全文
Jackson AP Eastwood H Bell SM Adu J Toomes C Carr IM Roberts E Hampshire DJ Crow YJ Mighell AJ Karbani G Jafri H Rashid Y Mueller RF Markham AF Woods CG 《American journal of human genetics》2002,71(1):136-142
Primary microcephaly (MIM 251200) is an autosomal recessive neurodevelopmental condition in which there is a global reduction in cerebral cortex volume, to a size comparable with that of early hominids. We previously mapped the MCPH1 locus, for primary microcephaly, to chromosome 8p23, and here we report that a gene within this interval, encoding a BRCA1 C-terminal domain-containing protein, is mutated in MCPH1 families sharing an ancestral 8p23 haplotype. This gene, microcephalin, is expressed in the developing cerebral cortex of the fetal brain. Further study of this and related genes may provide important new insights into neocortical development and evolution. 相似文献