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81.
Sajjad Ahmad Hui Ma Muhammad Waheed Akhtar Yi-Heng Percival Zhang Xiao-Zhou Zhang 《Bioenergy Research》2014,7(1):381-388
Increasing specific activity of cellulase on solid cellulosic materials would be among the top priorities for second-generation biorefineries. However, the complicated relationship among the heterogeneity of solid cellulosic materials and different action mode cellulase components results in great challenges in cellulase engineering. We applied directed evolution to a Clostridium phytofermentans ISDg glycoside hydrolase family 9 processive endoglucanase (CpCel9) for enhanced hydrolytic performance by using Bacillus subtilis as a host for cloning and expression. Several CpCel9 mutants with both increased expression level and enhanced specific activity on the solid cellulosic material were obtained. The most active mutant, which also exhibits an increased expression level, had more than threefold specific activity than that of wild type on regenerated amorphous cellulose. Most mutation sites were located in the family 3 cellulose-binding module near to its catalytic module, which might guide the entrance of glucan into the catalytic module. This study suggested that directed evolution by combining B. subtilis secretory protein expression host and solid cellulosic substrates would be a powerful tool to evolve more active cellulase mutants for cost-effective biosaccharification process. 相似文献
82.
Sajjad Rafiq Margaret L. Russell Richard Webby Kevin Fonseca Marek Smieja Pardeep Singh Mark Loeb 《PloS one》2012,7(12)
Background
To evaluate if, among children aged 3 to 15 years, influenza vaccination for multiple seasons affects the proportion sero-protected.Methodology/Principal Findings
Participants were 131 healthy children aged 3–15 years. Participants were vaccinated with trivalent inactivated seasonal influenza vaccine (TIV) over the 2005–06, 2006–07 and 2007–8 seasons. Number of seasons vaccinated were categorized as one (2007–08); two (2007–08 and 2006–07 or 2007–08 and 2005–06) or three (2005–06, 2006–07, and 2007–08). Pre- and post-vaccination sera were collected four weeks apart. Antibody titres were determined by hemagglutination inhibition (HAI) assay using antigens to A/Solomon Islands/03/06 (H1N1), A/Wisconsin/67/05 (H3N2) and B/Malaysia/2506/04. The proportions sero-protected were compared by number of seasons vaccinated using cut-points for seroprotection of 1∶40 vs. 1∶320. The proportions of children sero-protected against H1N1 and H3N2 was high (>85%) regardless of number of seasons vaccinated and regardless of cut-point for seroprotection. For B Malaysia there was no change in proportions sero-protected by number of seasons vaccinated; however the proportions protected were lower than for H1N1 and H3N2, and there was a lower proportion sero-protected when the higher, compared to lower, cut-point was used for sero-protection.Conclusion/Significance
The proportion of children sero-protected is not affected by number of seasons vaccinated. 相似文献83.
Shakeel Ahmed Ansari Rukhsana Satar Fahad Alam Mohammed Husein Alqahtani Adeel Gulzar Chaudhary Muhammad Imran Naseer Sajjad Karim Ishfaq Ahmed Sheikh 《Process Biochemistry》2012,47(12):2427-2433
The present study demonstrates synthesis, characterization and surface functionalization of silver nanoparticles (AgNPs) via glutaraldehyde for high yield immobilization of Aspergillus oryzae β-galactosidase. Soluble β-galactosidase (SβG), enzyme adsorbed on unmodified AgNPs (UβG) and surface modified AgNPs (MβG) showed same pH-optima at pH 4.5. However, it was observed that MβG exhibited enhanced pH stability toward acidic and alkaline sides, and increased temperature resistance as compared to SβG and UβG. Michaelis constant, Km was increased nearly three-folds for MβG while Vmax for soluble and MβG was 0.515 mM/min and 0.495 mM/min, respectively. Furthermore, MβG showed greater resistance to product inhibition mediated by galactose as compared to it soluble counterpart and exhibited excellent catalytic activity even after its fourth successive reuse. The remarkable bioconversion rates of lactose from milk in batch reactors further revealed an attractive catalytic efficiency of β-galactosidase adsorbed on surface functionalized AgNPs thereby promoting its use in the production of lactose free dairy products. 相似文献
84.
Shen DM Brady EJ Candelore MR Dallas-Yang Q Ding VD Feeney WP Jiang G McCann ME Mock S Qureshi SA Saperstein R Shen X Tong X Tota LM Wright MJ Yang X Zheng S Chapman KT Zhang BB Tata JR Parmee ER 《Bioorganic & medicinal chemistry letters》2011,21(1):76-81
A novel class of 1,3,5-pyrazoles has been discovered as potent human glucagon receptor antagonists. Notably, compound 26 is orally bioavailable in several preclinical species and shows selectivity towards cardiac ion channels, other family B receptors such hGIP and hGLP1, and a large panel of enzymes and additional receptors. When dosed orally, compound 26 is efficacious in suppressing glucagon induced plasma glucose excursion in rhesus monkey and transgenic murine pharmacodynamic models at 1 and 10 mpk, respectively. 相似文献
85.
Elham Gholipour Houman Kahroba Nasim Soltani Parisa Samadi Parisa Sarvarian Sajjad VakiliSamiani Abbas Ali Hosein Pour Feizi Mohammad
Sadegh SoltaniZangbar Adel Baghersalimi Bahram Darbandi Aliakbar Movassaghpour Mehdi Talebi Roza Motavalli Amir Mehdizadeh Abdolhassan Kazemi Mehdi Yousefi 《Journal of cellular and molecular medicine》2022,26(16):4566
86.
Discovery of novel, potent, and orally active spiro-urea human glucagon receptor antagonists 总被引:4,自引:0,他引:4
Shen DM Zhang F Brady EJ Candelore MR Dallas-Yang Q Ding VD Dragovic J Feeney WP Jiang G McCann PE Mock S Qureshi SA Saperstein R Shen X Tamvakopoulos C Tong X Tota LM Wright MJ Yang X Zheng S Chapman KT Zhang BB Tata JR Parmee ER 《Bioorganic & medicinal chemistry letters》2005,15(20):4564-4569
A novel class of spiro-ureas has been discovered as potent human glucagon receptor antagonists in both binding and functional assays. Preliminary studies have revealed that compound 15 is an orally active human glucagon receptor antagonist in a transgenic murine pharmacodynamic model at 10 and 30 mpk. Compound 15 is orally bioavailable in several preclinical species and shows selectivity toward cardiac ion channels and other family B receptors, such as hGIP1 and hGLP. 相似文献
87.
Ehsan Ullah Mughal Asif Javid Amina Sadiq Shahzad Murtaza Muhammad Naveed Zafar Bilal Ahmad Khan Sajjad Hussain Sumrra Muhammad Nawaz Tahir Khalid Mohammed Khan 《Bioorganic & medicinal chemistry》2018,26(12):3696-3706
The prime objective of this research work is to prepare readily soluble synthetic analogues of naturally occurring 3-O-flavonol glycosides and then investigate the influence of various substituents on biological properties of synthetic compounds. In this context, a series of varyingly substituted 3-O-flavonol glycosides have been designed, synthesized and characterized efficiently. The structures of synthetic molecules were unambiguously corroborated by IR, 1H, 13C NMR and ESI-MS spectroscopic techniques. The structure of compound 22 was also analyzed by X-ray diffraction analysis. All the synthetic compounds (21–30) were evaluated for in vitro inhibitory potential against cholinesterase enzymes. The results displayed that most of the derivatives were potent inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with varying degree of IC50 values. The experimental results were further encouraged by molecular docking studies in order to explore their binding behavior with the active pocket of AChE and BChE enzymes. The experimental and theoretical results are in parallel with one another. 相似文献
88.
Sajjad Salari Maedeh Ghasemi Javad Fahanik-Babaei Reza Saghiri Remy Sauve Afsaneh Eliassi 《PloS one》2015,10(5)
We report in a previous study the presence of a large conductance K+ channel in the membrane of rough endoplasmic reticulum (RER) from rat hepatocytes incorporated into lipid bilayers. Channel activity in this case was found to decrease in presence of ATP 100 µM on the cytoplasmic side and was totally inhibited at ATP concentrations greater than 0.25 mM. Although such features would be compatible with the presence of a KATP channel in the RER, recent data obtained from a brain mitochondrial inner membrane preparation have provided evidence for a Maxi-K channel which could also be blocked by ATP within the mM concentration range. A series of channel incorporation experiments was thus undertaken to determine if the ATP-sensitive channel originally observed in the RER corresponds to KATP channel. Our results indicate that the gating and permeation properties of this channel are unaffected by the addition of 800 nM charybdotoxin and 1 µM iberiotoxin, but appeared sensitive to 10 mM TEA and 2.5 mM ATP. Furthermore, adding 100 µM glibenclamide at positive potentials and 400 µM tolbutamide at negative or positive voltages caused a strong inhibition of channel activity. Finally Western blot analyses provided evidence for Kir6.2, SUR1 and/or SUR2B, and SUR2A expression in our RER fractions. It was concluded on the basis of these observations that the channel previously characterized in RER membranes corresponds to KATP, suggesting that opening of this channel may enhance Ca2+ releases, alter the dynamics of the Ca2+ transient and prevent accumulation of Ca2+ in the ER during Ca2+ overload. 相似文献
89.
Muhammad Ashfaq Paul D. N. Hebert M. Sajjad Mirza Arif M. Khan Shahid Mansoor Ghulam S. Shah Yusuf Zafar 《PloS one》2014,9(8)
Background
Although whiteflies (Bemisia tabaci complex) are an important pest of cotton in Pakistan, its taxonomic diversity is poorly understood. As DNA barcoding is an effective tool for resolving species complexes and analyzing species distributions, we used this approach to analyze genetic diversity in the B. tabaci complex and map the distribution of B. tabaci lineages in cotton growing areas of Pakistan.Methods/Principal Findings
Sequence diversity in the DNA barcode region (mtCOI-5′) was examined in 593 whiteflies from Pakistan to determine the number of whitefly species and their distributions in the cotton-growing areas of Punjab and Sindh provinces. These new records were integrated with another 173 barcode sequences for B. tabaci, most from India, to better understand regional whitefly diversity. The Barcode Index Number (BIN) System assigned the 766 sequences to 15 BINs, including nine from Pakistan. Representative specimens of each Pakistan BIN were analyzed for mtCOI-3′ to allow their assignment to one of the putative species in the B. tabaci complex recognized on the basis of sequence variation in this gene region. This analysis revealed the presence of Asia II 1, Middle East-Asia Minor 1, Asia 1, Asia II 5, Asia II 7, and a new lineage “Pakistan”. The first two taxa were found in both Punjab and Sindh, but Asia 1 was only detected in Sindh, while Asia II 5, Asia II 7 and “Pakistan” were only present in Punjab. The haplotype networks showed that most haplotypes of Asia II 1, a species implicated in transmission of the cotton leaf curl virus, occurred in both India and Pakistan.Conclusions
DNA barcodes successfully discriminated cryptic species in B. tabaci complex. The dominant haplotypes in the B. tabaci complex were shared by India and Pakistan. Asia II 1 was previously restricted to Punjab, but is now the dominant lineage in southern Sindh; its southward spread may have serious implications for cotton plantations in this region. 相似文献90.
Asif Sajjad Mudssar Ali Shafqat Saeed Muhammad Amjad Bashir Intazar Ali Khalid Ali Khan Hamed A. Ghramh Mohammad Javed Ansari 《Saudi Journal of Biological Sciences》2019,26(7):1799-1803
The yearlong association of a native bee, Pseudapis oxybeloides (Halictidae: Hymenoptera) was studied with 72 plant species in a sub-tropical planted forest and some adjacent agricultural landscapes at Multan, Pakistan. The study resulted in 66 interactions of P. oxybeloides with only 24 plant species in 15 families while other 48 plant species were not visited by this bee. The maximum abundance of P. oxybeloides (7–9 individuals) was recorded on Achyranthes aspera and Launaea procumbens followed by Ageratum conyzoides, Trianthema portulacastrum and Cleome viscosa (5–6 individuals). Majority (19) of plant species were visited by only 1–4 individuals. The bee activity was started in the month of March which attained its peak in May followed by a gradual decline until September. No bees were observed during the months of January and February. There was a significant positive relationship between bee abundance and number of flowering plant species. Bee abundance had a strong positive relationship with temperature while it had a strong negative relationship with relative humidity (%). Floral abundance increased with the number of flowering plant species while it was not influenced by floral span of plant species. Besides giving the floral host plants of P. oxybeloides, the current study also gives a better understanding of its seasonality along with its relationships with different biotic and abiotic factors under local conditions. These findings can help in maintaining and managing P. oxybeloides population particularly and other native bees in general at local scale. 相似文献