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211.
Malik R Bora RS Gupta D Sharma P Arya R Chaudhary S Saini KS 《Applied microbiology and biotechnology》2008,77(5):1167-1173
Phosphodiesterases (PDEs) constitute a superfamily of enzymes that plays an important role in signal transduction by catalysing
the hydrolysis of cAMP and cGMP. cDNA encoding PDE7A1 subtype was cloned and a stable recombinant HEK 293 cell line expressing
high levels of PDE7A1 was generated. Transient transfection of pCRE-Luc plasmid, harboring luciferase reporter gene into the
stable recombinant cell line and subsequent treatment with PDE7 inhibitor, resulted in a dose-dependent increase in luciferase
activity. This method provides a simple and sensitive cell-based assay for screening of PDE7 selective inhibitors for the
treatment of T cell mediated diseases.
Renu Malik and Roop Singh Bora contributed equally to this work. 相似文献
212.
Sharma R Nagar M Agarwal M Sharma H 《Journal of enzyme inhibition and medicinal chemistry》2009,24(1):197-204
The reaction of cobalt(II) chloride with a new class of thiosemicarbazones viz; cis-3,7-dimethyl-2,6-octadienthiosemicarbazone(CDOTSC; L(1)H) and 3,7-dimethyl-6-octenethiosemicarbazone (DOTSC; L(2)H) and N-phthaloyl derivative of DL-glycine(A(1)H), L-alanine(A(2)H) or L-valine(A(3)H) in 1:1:1 molar ratio in dry refluxing ethanol have been studied. All the isolated complexes have the general composition [Co(L)(A)]. Tentative structures are proposed for these complexes based upon elemental analysis, electrical conductances, magnetic moment, molecular weight determination and spectral (IR, electronic) studies.The ligands and Co(II) complexes have been tested for their antibacterial and antifungal activities against three bacterial strains S. aureus, B. subtilis, E. coli and two fungal strains F. moniliformae and M. phaseolina. Attempts have been made to establish a correlation between the antibacterial and antifungal activity and the structures of products. 相似文献
213.
Characterization of replication fork and phosphorylation stimulated Plasmodium falciparum helicase 45 总被引:1,自引:0,他引:1
Helicases are essential enzymes, which play important role in the metabolism of nucleic acids. In the present study we report further characterization of PfH45 (Plasmodium falciparum helicase 45), which is an essential enzyme for parasite survival. The results show that the helicase activity of PfH45 is significantly stimulated by replication fork like structure. The studies using truncated derivatives of PfH45 show that its nucleic acid dependent ATPase activity resides in the N-terminal one third of the protein and its RNA and DNA-binding activity predominantly resides in the C-terminal two third of the protein. The phosphorylation of PfH45 by protein kinase C at Ser and Thr residues stimulated its DNA and RNA helicase and ssDNA and RNA-dependent ATPase activities. DNA-interacting compounds actinomycin, DAPI, daunorubicin, ethidium bromide, netropsin and nogalamycin were able to inhibit the helicase and ssDNA-dependent ATPase activity with apparent IC50 values ranging from 0.5 to 5.0 microM respectively. These compounds distinctively inhibit the helicase activity probably by forming complex with DNA and obstructing enzyme movement. 相似文献
214.
Srivastava R Liu JX Howell SH 《The Plant journal : for cell and molecular biology》2008,56(2):219-227
Phytosulfokines (PSKs) are secreted, sulfated peptide hormones derived from larger prepropeptide precursors. Proteolytic processing of one of the precursors, AtPSK4, was demonstrated by cleavage of a preproAtPSK4-myc transgene product to AtPSK4-myc. Cleavage of proAtPSK4 was induced by placing root explants in tissue culture. The processing of proAtPSK4 was dependent on AtSBT1.1, a subtilisin-like serine protease, encoded by one of 56 subtilase genes in Arabidopsis. The gene encoding AtSBT1.1 was up-regulated following the transfer of root explants to tissue culture, suggesting that activation of the proteolytic machinery that cleaves proAtPSK4 is dependent on AtSBT1.1 expression. We also demonstrated that a fluorogenic peptide representing the putative subtilase recognition site in proAtPSK4 is cleaved in vitro by affinity-purified AtSBT1.1. An alanine scan through the recognition site peptide indicated that AtSBT1.1 is fairly specific for the AtPSK4 precursor. Thus, this peptide growth factor, which promotes callus formation in culture, is proteolytically cleaved from its precursor by a specific plant subtilase encoded by a gene that is up-regulated during the process of transferring root explants to tissue culture. 相似文献
215.
Baweja RB Zaman MS Mattoo AR Sharma K Tripathi V Aggarwal A Dubey GP Kurupati RK Ganguli M Chaudhury NK Sen S Das TK Gade WN Singh Y 《Archives of microbiology》2008,189(1):71-79
Bacillus anthracis makes highly stable, heat-resistant spores which remain viable for decades. Effect of various stress conditions on sporulation
in B. anthracis was studied in nutrient-deprived and sporulation medium adjusted to various pH and temperatures. The results revealed that
sporulation efficiency was dependent on conditions prevailing during sporulation. Sporulation occurred earlier in culture
sporulating at alkaline pH or in PBS than control. Spores formed in PBS were highly sensitive towards spore denaturants whereas,
those formed at 45°C were highly resistant. The decimal reduction time (D-10 time) of the spores formed at 45°C by wet heat,
2 M HCl, 2 M NaOH and 2 M H2O2 was higher than the respective D-10 time for the spores formed in PBS. The dipicolinic acid (DPA) content and germination
efficiency was highest in spores formed at 45°C. Since DPA is related to spore sensitivity towards heat and chemicals, the
increased DPA content of spores prepared at 45°C may be responsible for increased resistance to wet heat and other denaturants.
The size of spores formed at 45°C was smallest amongst all. The study reveals that temperature, pH and nutrient availability
during sporulation affect properties of B. anthracis spores. 相似文献
216.
The genetic basis of seedling and adult-plant leaf rust resistance was analysed in wheat lines CS 2A/2M 4/2 and CS 2D/2M 3/8, which are reference lines for the leaf rust resistance gene Lr28. Some seedlings of CS 2A/2M 4/2 were susceptible to Indian Puccinia triticina (Pt) pathotypes 77-1, 77-2 and 77-5. These susceptible seedlings exhibited resistance at the adult-plant growth stage. In contrast, CS 2D/2M 3/8 showed resistance to all Pt pathotypes both at the seedling and adult-plant growth stages. The analysis of inheritance in the susceptible plants of CS 2A/2M 4/2 (CS 2A/2M 4/2 APR selection) and CS 2D/2M 3/8 against Pt 77-5 (the frequently occurring Pt pathotype from the Indian subcontinent), indicated that line CS 2D/2M 3/8 was fixed for a dominant gene, presumed to be Lr28, whereas line CS 2A/2M 4/2 was heterogeneous for Lr28. The adult-plant resistance in the CS 2A/2M 4/2 APR selection was conferred by an unknown recessive gene. 相似文献
217.
Mukesh?Kumar?Kanwar Andrzej?Bajguz Jie?ZhouEmail author Renu?BhardwajEmail author 《Journal of Plant Growth Regulation》2017,36(4):1002-1030
Brassinosteroids (BRs) are the polyhydroxylated plant hormones sharing a common resemblance with animal steroids. They are active even at very low concentrations and are implicated for their pleiotropic involvement in diverse physiological processes and defense strategies during stress in plants. These compounds are well apparent in the plant kingdom with higher amounts in juvenile tissues. A total of 62 steroidal compounds have been identified so far. Keeping their significance in mind, researchers not only have worked extensively on their isolation, but also they were synthesizing their synthetic isomers. Different analytical techniques like HPLC, GC-MS, LC-MS/MS, UPLC-MS/MS, and bioassay-based methods have been used for their isolation, detection, and characterization from composite plant materials. Therefore, this review provides comprehensive information to the readers intending to isolate and characterize BRs, using either laborious techniques or modern-day more efficient methods. 相似文献
218.
DNA helicases are molecular 'motor' enzymes that use the energy of NTP hydrolysis to separate transiently energetically stable duplex DNA into single strands. They are therefore essential in nearly all DNA metabolic transactions. They act as essential molecular tools for the cellular machinery. Since the discovery of the first DNA helicase in Escherichia coli in 1976, several have been isolated from both prokaryotic and eukaryotic systems. DNA helicases generally bind to ssDNA or ssDNA/dsDNA junctions and translocate mainly unidirectionally along the bound strand and disrupt the hydrogen bonds between the duplexes. Most helicases contain conserved motifs which act as an engine to drive DNA unwinding. Crystal structures have revealed an underlying common structural fold for their function. These structures suggest the role of the helicase motifs in catalytic function and offer clues as to how these proteins can translocate and unwind DNA. The genes containing helicase motifs may have evolved from a common ancestor. In this review we cover the conserved motifs, structural information, mechanism of DNA unwinding and translocation, and functional aspects of DNA helicases. 相似文献
219.
Drought-induced spikelet sterility is associated with an inefficient antioxidant defence in rice panicles 总被引:4,自引:0,他引:4
Water stress-induced spikelet sterility limits rice production under upland conditions. The causes of spikelet sterility under drought stress are poorly understood. In this study the role of antioxidant defence management in drought-induced spikelet sterility was investigated in two rice ( Oryza sativa ) genotypes differing in drought resistance. Drought-resistant N22 genotype showed less water stress-induced spikelet sterility when compared to the susceptible N118 genotype under upland conditions. The N22 panicles maintained higher RWC and turgor potential and lower H2 O2 levels across the developmental stages under water stress than that of N118 panicles. Drought-induced enhancement in superoxide dismutase (SOD, EC 1.15.1.1) activity coupled with higher ascorbate (AsA), glutathione (GSH) content and enhanced ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) activities resulted in lower H2 O2 levels in N22 panicles. In contrast, insufficient enhancement in SOD, APX and GR activities resulted in relatively higher H2 O2 levels under water stress in N118 panicles. The N22 panicles exhibited a higher number of SOD and APX isozymes in comparison with N118 panicles that might provide better reactive oxygen species scavenging. Hence it is concluded that well-equipped antioxidant defence plays an important role in minimizing water stress-induced spikelet sterility in upland rice. 相似文献
220.
Irina A. Omelchenko Renu K Jain Mohammed A. Junaid S.L.N. Rao Charles N. Allen 《Neurochemical research》1999,24(6):791-797
Lathyrism is a non-progressive motor neuron disease produced by consumption of the excitatory amino acid, 3-N-oxalyl-L-2,3-diaminopropanoic acid (-ODAP). To learn more about the mechanisms underlying Lathyrism three structural analogs of -ODAP were synthesized. Carboxymethyl-,-diaminopropanoic acid (CMDAP) evoked inward currents which were antagonized by APV (30 M), but not by CNQX (10 M). N-acetyl-,-diaminopropanoic acid (ADAP) evoked no detectable ionic currents but potentiated N-methyl-D-aspartate (NMDA)-activated currents. The potentiation of NMDA currents by ADAP was blocked by 7-chlorokynurenic acid. Carboxymethylcysteine (CMC) did not activate any detectable ionic currents. None of the three -ODAP analogs produced visible symptoms of toxicity in day old chicks when administered for 2–3 consecutive days. Ligand binding studies demonstrated that all the three compounds were effective to in displacing [3H]glutamate. The maximum inhibition was 92% for CMDAP, 61% for ADAP, 65% for CMC and 99% for -ODAP. These data indicate that analogs of -ODAP may interact with glutamate receptors without producing neurotoxicity. 相似文献