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71.
Mycobacterium smegmatis topoisomerase I differs from the typical type IA topoisomerase in many properties. The enzyme recognizes both single and double-stranded DNA with high affinity and makes sequence-specific contacts during DNA relaxation reaction. The enzyme has a conserved N-terminal domain and a highly varied C-terminal domain, which lacks the characteristic zinc binding motifs found in most of the type I eubacterial enzymes. The roles of the individual domains of the enzyme in the topoisomerase I catalyzed reactions were examined by comparing the properties of full-length topoisomerase I with those of truncated polypeptides lacking the conserved N-terminal or the divergent C-terminal region. The N-terminal larger fragment retained the site-specific binding, DNA cleavage and religation properties, hallmark characteristics of the full-length M.smegmatis topoisomerase I. In contrast, the non-conserved C-terminal fragment lacking the typical DNA binding motif, exhibited non-specific DNA binding behaviour. The two polypeptide fragments, on their own do not catalyze DNA relaxation reaction. The relaxation activity is restored when both the fragments are mixed in vitro reconstituting the enzyme function. These results along with the DNA interaction pattern of the proteins implicate an essential role for the C-terminal region in single-strand DNA passage between the two transesterification reactions catalyzed by the N-terminal domain. 相似文献
72.
The aim of the present investigation was to prepare glipizide matrix transdermal systems using the combinations of ethyl cellulose/polyvinylpyrrolidone and Eudragit RL-100/Eudragit RS-100. The systems were evaluated for various in vitro (drug content, drug permeation, scanning electron microscopy and drug-polymer interactions) and in vivo (acute and long-term hypoglycemic activity, biochemical and histopathological studies, skin irritation and pharmacokinetic studies in mice) parameters. Drug content of the patches was found to be more than 98%. Variations in drug permeation profiles were observed among various formulations. The scanning electron microscopy of the patches showed the formation of pores on the surface after in vitro permeation studies. The drug-polymer interaction results suggested no interaction between drug and polymers. The in vivo results revealed that the patches successfully prevented the severe hypoglycemia in the initial hours and they were also effective on chronic application. The transdermal route exhibited negligible skin irritation and produced better improvement with all the tested in vivo parameters compared to oral administration. 相似文献
73.
Maria Pratheepa Sushil Kumar Jalali Robinson Silvester Arokiaraj Thiruvengadam Venkatesan Mandadi Nagesh Madhusmita Panda Sharath Pattar 《Bioinformation》2014,10(2):98-100
Insect Barcode Information System called as Insect Barcode Informática (IBIn) is an online database resource developed by the
National Bureau of Agriculturally Important Insects, Bangalore. This database provides acquisition, storage, analysis and
publication of DNA barcode records of agriculturally important insects, for researchers specifically in India and other countries. It
bridges a gap in bioinformatics by integrating molecular, morphological and distribution details of agriculturally important insects.
IBIn was developed using PHP/My SQL by using relational database management concept. This database is based on the client–
server architecture, where many clients can access data simultaneously. IBIn is freely available on-line and is user-friendly. IBIn
allows the registered users to input new information, search and view information related to DNA barcode of agriculturally
important insects.This paper provides a current status of insect barcode in India and brief introduction about the database IBIn.
Availability
http://www.nabg-nbaii.res.in/barcode 相似文献74.
Katharigatta N. Venugopala Sandeep Chandrashekharappa Pran Kishore Deb Christophe Tratrat Melendhran Pillay Deepak Chopra Nizar A. Al-Shari Wafa Hourani Lina A. Dahabiyeh Pobitra Borah Rahul D. Nagdeve Susanta K. Nayak Basavaraj Padmashali Mohamed A. Morsy Bandar E. Aldhubiab Mahesh Attimarad Anroop B. Nair Nagaraja Sreeharsha Michelyne Haroun Sheena Shashikanth Viresh Mohanlall Raghuprasad Mailavaram 《Journal of enzyme inhibition and medicinal chemistry》2021,36(1):1472
A series of 1,2,3-trisubstituted indolizines (2a–2f, 3a–3d, and 4a–4c) were screened for in vitro whole-cell anti-tubercular activity against the susceptible H37Rv and multidrug-resistant (MDR) Mycobacterium tuberculosis (MTB) strains. Compounds 2b–2d, 3a–3d, and 4a–4c were active against the H37Rv-MTB strain with minimum inhibitory concentration (MIC) ranging from 4 to 32 µg/mL, whereas the indolizines 4a–4c, with ethyl ester group at the 4-position of the benzoyl ring also exhibited anti-MDR-MTB activity (MIC = 16–64 µg/mL). In silico docking study revealed the enoyl-acyl carrier protein reductase (InhA) and anthranilate phosphoribosyltransferase as potential molecular targets for the indolizines. The X-ray diffraction analysis of the compound 4b was also carried out. Further, a safety study (in silico and in vitro) demonstrated no toxicity for these compounds. Thus, the indolizines warrant further development and may represent a novel promising class of InhA inhibitors and multi-targeting agents to combat drug-sensitive and drug-resistant MTB strains. 相似文献
75.
Massimo Cocchia Natalay Kouprina Sung-Jae Kim Vladimir Larionov David Schlessinger Ramaiah Nagaraja 《Nucleic acids research》2000,28(17):e81
A method has been established to convert pYAC4-based linear yeast artificial chromosomes (YACs) into circular chromosomes that can also be propagated in Escherichia coli cells as bacterial artificial chromosomes (BACs). The circularization is based on use of a vector that contains a yeast dominant selectable marker (G418R), a BAC cassette and short targeting sequences adjacent to the edges of the insert in the pYAC4 vector. When it is introduced into yeast, the vector recombines with the YAC target sequences to form a circular molecule, retaining the insert but discarding most of the sequences of the YAC telomeric arms. YACs up to 670 kb can be efficiently circularized using this vector. Re-isolation of megabase-size YAC inserts as a set of overlapping circular YAC/BACs, based on the use of an Alu-containing targeting vector, is also described. We have shown that circular DNA molecules up to 250 kb can be efficiently and accurately transferred into E.coli cells by electroporation. Larger circular DNAs cannot be moved into bacterial cells, but can be purified away from linear yeast chromosomes. We propose that the described system for generation of circular YAC derivatives can facilitate sequencing as well as functional analysis of genomic regions. 相似文献
76.
Rapid 5′ Nuclease (TaqMan) Assay for Detection of Virulent Strains of Yersinia enterocolitica 下载免费PDF全文
A. Vishnubhatla D. Y. C. Fung R. D. Oberst M. P. Hays T. G. Nagaraja S. J. A. Flood 《Applied microbiology》2000,66(9):4131-4135
We have developed a rapid procedure for the detection of virulent Yersinia enterocolitica in ground pork by combining a previously described PCR with fluorescent dye technologies. The detection method, known as the fluorogenic 5′ nuclease assay (TaqMan), produces results by measuring the fluorescence produced during PCR amplification, requiring no post-PCR processing. The specificity of the chromosomal yst gene-based assay was tested with 28 bacterial isolates that included 7 pathogenic and 7 nonpathogenic serotypes of Y. enterocolitica, other species of Yersinia (Y. aldovae, Y. pseudotuberculosis, Y. mollaretti, Y. intermedia, Y. bercovieri, Y. ruckeri, Y. frederiksenii, and Y. kristensenii), and other enteric bacteria (Escherichia, Salmonella, Citrobacter, and Flavobacterium). The assay was 100% specific in identifying the pathogenic strains of Y. enterocolitica. The sensitivity of the assay was found to be ≥102 CFU/ml in pure cultures and ≥103 CFU/g in spiked ground pork samples. Results of the assay with food enrichments prespiked with Y. enterocolitica serotypes O:3 and O:9 were comparable to standard culture results. Of the 100 field samples (ground pork) tested, 35 were positive for virulent Y. enterocolitica with both 5′ nuclease assay and conventional virulence tests. After overnight enrichment the entire assay, including DNA extraction, amplification, and detection, could be completed within 5 h. 相似文献
77.
Siddamadappa Chandrashekaran Padmanabhan Babu Valakunja Nagaraja 《Journal of biosciences》1999,24(3):269-277
The genes encoding theKpnI restriction endonuclease and methyltransferase fromKlebsiella pneumoniae have been cloned and expressed inEscherchia coli using a two plasmid strategy. The gene forKpnI methylase with its promoter was cloned and expressed in pACYC184. Even though the methylase clone is in a low copy number
plasmid pACMK, high level expression of methylase is achieved. A hyper-expressing clone ofKpnI endonuclease, pETRK was engineered by cloning the R gene into the T7 expression system. This strategy resulted in over-expression
ofKpnI endonuclease to about 15–30% of cellular protein. Both the enzymes were purified using a single Chromatographic step to
apparent homogeneity. The yield of purified endonuclease and methylase from one liter of culture was approximately 30 and
6 mg respectively. Electrophoretic mobility shift assays show that both the enzymes are capable of binding to specific recognition
sequence in the absence of any cofactors. The complexes ofKpnI methyl transferase and endonuclease with their cognate site exhibit distinctive behaviour with respect to ionic requirement. 相似文献
78.
79.
Omasal contents were collected from slaughtered cattle (n = 54), bison (n = 15), and sheep (n = 40) to determine numbers and generic distribution of ciliated protozoa. Total protozoan numbers were significantly lower in omasal contents than in ruminal contents of all three species, but the percent composition of all protozoan genera was similar between omasal and ruminal populations. The highest numbers of omasal protozoa found were 7.61 X 10(5)/g in cattle, 7.01 X 10(5)/g in bison, and 1.29 X 10(6)/g in sheep. Omasal dry matter was significantly higher than ruminal dry matter in all species and ranged up to 51.5% in cattle fed high-concentrate diets. The omasal pH was similar to the ruminal pH in all species. The number of omasal laminae averaged 149, 145, and 74 for cattle, bison, and sheep, respectively. Although protozoan concentrations in omasal contents were approximately 80% lower than those in ruminal contents, the omasum harbored relatively high numbers of ciliated protozoa. The resident omasal protozoa are extremely difficult to remove, particularly in cattle, and apparently are responsible for reinoculating transiently defaunated rumens. 相似文献
80.
Two type I restriction enzymes from Salmonella species. Purification and DNA recognition sequences 总被引:9,自引:0,他引:9
We have purified the type I restriction enzymes SB and SP from Salmonella typhimurium and S. potsdam, respectively, and determined the DNA sequences that they recognize. These sequences resemble those previously determined for the type I enzymes, EcoB, EcoK and EcoA, in that the specific part of the sequence is divided into two domains by a spacer of non-specific sequence that has a fixed length for each enzyme. Two main differences from the previously determined sequences are seen. Both of the new sequences are degenerate and one of them, SB, has one trinucleotide and one pentanucleotide-specific domain rather than the trinucleotide and tetranucleotide domains seen for all of the other enzymes. The only conserved features of the recognition sequences are the adenosyl residues that are methylated in the modification reaction. For all of the enzymes these are situated ten or 11 base-pairs apart, one on each strand of the DNA. This suggests that the enzymes bind to DNA along one face of the double helix making protein-DNA interaction in two successive major grooves with most of the non-specific spacer sequence in the intervening minor groove. 相似文献