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41.
Mouse peritoneal macrophages (MPM) when elicited by the antioxidant ascorbic acid have been found to be significantly stimulatory, exhibiting marked alteration at the cellular and enzyme levels. Alterations recorded were as follows--cellular yield per mouse, their protein content, lysosomal acid hydrolase levels and capability to phagocyte, all were significantly enhanced. The new stimulant was observed to produce no synergistic action on MPM when thioglycollate, BCG or endotoxin along with the same stimulated the latter. Levels of antioxidants like ascorbic acid and glutathione were found to be enhanced in elicited macrophages whereas superoxide dismutase levels varied when the three above stimulators were administered. However, the ascorbic acid elicited cells showed an increase in glutathione levels and a decrease in SOD levels but no change in total intracellular ascorbic acid levels. Further, though ascorbic acid interaction enhanced the phagocytic capability of MPM as compared to resident cells, no significant boosting of phagocytic process could be observed when each of three stimulators coupled with ascorbic acid was used for macrophage elicitation. 相似文献
42.
Chakrabarty R Viswakarma N Bhat SR Kirti PB Singh BD Chopra VL 《Journal of biosciences》2002,27(5):495-502
A number of factors that are known to influence genetic transformation were evaluated to optimizeAgrobacterium-mediated transformation of hypocotyl explants of cauliflower variety Pusa Snowball K-1. The binary vector p35SGUSINT mobilized intoAgrobacterium strain GV2260 was used for transformation and transient GUS expression was used as the basis for identifying the most appropriate
conditions for transformation. Explant age, preculture period, bacterial strain and density were found to be critical determinants
of transformation efficiency. Using the optimized protocol, the syntheticcryIA(b) gene was mobilized into cauliflower. Molecular analyses of transgenics established the integration and expression of the
transgene. Insect bioassays indicated the effectiveness of the transgene against infestation by diamondback moth (Plutella xylostella) larvae. 相似文献
43.
Ray R Das AK Dutta NK Chakrabarty AN Chaudhuri BN Seth S Dastidar SG 《Indian journal of experimental biology》2002,40(2):220-222
Sensitivity of 21 halophilic vibrios and 16 clinical isolates of non-halophilic vibrios was determined against a new possible antivibrio agent, a pyrimidine analogue, 4, 6-dimethylpyrimidine -2-thiol (4,6-DMPT). It appeared to be a vibriocidal agent, having a mean MIC and MBC of 32 microg/ml for halophilic strains and 64 microg/ml for non-halophilic strains and an LD50 of 300 mg/Kg body weight of mice. Thus, 4,6-DMPT may help an in vitro distinction between halophilic and non-halophilic vibrios. Sensitivity of these strains was also studied with respect to pteridine, crystal violet and Tween 80 hydrolysis as further markers distinguishing between these 2 groups which could also be differentiated by their growth on TCBS or/and CLED media. 相似文献
44.
Novel Pathway for Conversion of Chlorohydroxyquinol to Maleylacetate in Burkholderia cepacia AC1100
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Olga Zaborina Dayna L. Daubaras Anna Zago Luying Xun Katsuhiko Saido Thomas Klem Dejan Nikolic A. M. Chakrabarty 《Journal of bacteriology》1998,180(17):4667-4675
Burkholderia cepacia AC1100 metabolizes 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) via formation of 5-chlorohydroxyquinol (5-CHQ), hydroxyquinol (HQ), maleylacetate, and β-oxoadipate. The step(s) leading to the dechlorination of 5-CHQ to HQ has remained unidentified. We demonstrate that a dechlorinating enzyme, TftG, catalyzes the conversion of 5-CHQ to hydroxybenzoquinone, which is then reduced to HQ by a hydroxybenzoquinone reductase (HBQ reductase). HQ is subsequently converted to maleylacetate by hydroxyquinol 1,2-dioxygenase (HQDO). All three enzymes were purified. We demonstrate specific product formation by colorimetric assay and mass spectrometry when 5-CHQ is treated successively with the three enzymes: TftG, TftG plus HBQ reductase, and TftG plus HBQ reductase plus HQDO. This study delineates the complete enzymatic pathway for the degradation of 5-CHQ to maleylacetate. 相似文献
45.
Sherry R. Jacob Vandana Tyagi Anuradha Agrawal Shyamal K. Chakrabarty Rishi K. Tyagi 《PloS one》2015,10(5)
Food security is a global concern amongst scientists, researchers and policy makers. No country is self-sufficient to address food security issues independently as almost all countries are inter-dependent for availability of plant genetic resources (PGR) in their national crop improvement programmes. Consultative Group of International Agricultural Research (CGIAR; in short CG) centres play an important role in conserving and distributing PGR through their genebanks. CG genebanks assembled the germplasm through collecting missions and acquisition the same from national genebanks of other countries. Using the Genesys Global Portal on Plant Genetic Resources, the World Information and Early Warning System (WIEWS) on Plant Genetic Resources for Food and Agriculture and other relevant databases, we analysed the conservation status of Indian-origin PGR accessions (both cultivated and wild forms possessed by India) in CG genebanks and other national genebanks, including the United States Department of Agriculture (USDA) genebanks, which can be considered as an indicator of Indian contribution to the global germplasm collection. A total of 28,027,770 accessions are being conserved world-wide by 446 organizations represented in Genesys; of these, 3.78% (100,607) are Indian-origin accessions. Similarly, 62,920 Indian-origin accessions (8.73%) have been conserved in CG genebanks which are accessible to the global research community for utilization in their respective crop improvement programmes. A total of 60 genebanks including 11 CG genebanks have deposited 824,625 accessions of PGR in the Svalbard Global Seed Vault (SGSV) as safety duplicates; the average number of accessions deposited by each genebank is 13,744, and amongst them there are 66,339 Indian-origin accessions. In principle, India has contributed 4.85 times the number of germplasm accessions to SGSV, in comparison to the mean value (13,744) of any individual genebank including CG genebanks. More importantly, about 50% of the Indian-origin accessions deposited in SGSV are traditional varieties or landraces with defined traits which form the backbone of any crop gene pool. This paper is also attempting to correlate the global data on Indian-origin germplasm with the national germplasm export profile. The analysis from this paper is discussed with the perspective of possible implications in the access and benefit sharing regime of both the International Treaty on Plant Genetic Resources for Food and Agriculture and the newly enforced Nagoya Protocol under the Convention on Biological Diversity. 相似文献
46.
47.
Subhra Prakash Chakrabarty Hemalatha Balaram 《Biochimica et Biophysica Acta - Proteins and Proteomics》2010,1804(9):1743-1750
Reversible zinc chelation via thiol groups of cysteines leading to modulation of activity in redox regulated proteins forms a basis for switching on–off of various biochemical processes. Silent information regulator 2 (Sir2), a NAD+ dependent deacetylase, contains a non-catalytic zinc ion coordinated by thiol groups of cysteines. Using Plasmodium falciparum Sir2 (PfSir2), we have examined the effect of zinc removal on the structure and activity of this enzyme. Our studies show that the enzyme with high affinity for zinc exhibits partial collapse of structure upon removal of the metal ion. Zinc reconstitution of apo PfSir2 led to recovery of both structure and activity highlighting the reversibility of the process. 相似文献
48.
Y. H. Dewir D. Chakrabarty S. -H. Lee E. -J. Hahn K. -Y. Paek 《Biologia Plantarum》2010,54(2):357-360
The present study reports an efficient protocol for indirect shoot organogenesis and plantlets regeneration of Withania somnifera (L.) Dunal. Leaf explants were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations and
combinations of 6-benzylaminopurine (BAP) and indole-3-acetic acid (IAA). The highest callus induction rate (89.5 %) and shoot
regeneration rate (92 %) were obtained when 2 mg dm−3 BAP was combined with 0.5 mg dm−3 IAA. Three major withanolides (withaferine A, 12-deoxywithastramonolide and withanolide A) were investigated in different
plant organs from in vitro and greenhouse grown plants. Leaves contained higher contents of withanolides and phenolics than roots or stems, whereas
roots contained the highest contents of flavonoids and polysacharides. In vitro grown plants contained greater contents of phenolics, flavonoids and polysaccharides while lower contents of withanolides
than greenhouse grown plants. 相似文献
49.
Six parent and their 12 gamma ray-induced somatic flower colour mutants of garden rose were characterized to discriminate
the mutants from their respective parents and understanding the genetic diversity using Random amplification of polymorphic
DNA (RAPD) markers. Out of 20 primers screened, 14 primers yielded completely identical fragments patterns. The other 7 primers
gave highly polymorphic banding patterns among the radiomutants. All the cultivars were identified by using only 7 primers.
Moreover, individual mutants were also distinguished by unique RAPD marker bands. Based on the presence or absence of the
48 polymorphic bands, the genetic variations within and among the 18 cultivars were measured. Genetic distance between all
18 cultivars varied from 0.40 to 0.91, as revealed by Jaccard’s coefficient matrix. A dendrogram was constructed based on
the similarity matrix using the Neighbor Joining Tree method showed three main clusters. The present RAPD analysis can be
used not only for estimating genetic diversity present in gamma ray-induced mutants but also for correct identification of
mutant/new varieties for their legal protection under plant variety rights. 相似文献
50.
Sanjay Dwivedi R. D. Tripathi Sudhakar Srivastava Ragini Singh Amit Kumar Preeti Tripathi Richa Dave U. N. Rai Debasis Chakrabarty P. K. Trivedi R. Tuli B. Adhikari M. K. Bag 《Protoplasma》2010,245(1-4):113-124
The exposure of paddy fields to arsenic (As) through groundwater irrigation is a serious concern that may not only lead to As accumulation to unacceptable levels but also interfere with mineral nutrients in rice grains. In the present field study, profiling of the mineral nutrients (iron (Fe), phosphorous, zinc, and selenium (Se)) was done in various rice genotypes with respect to As accumulation. A significant genotypic variation was observed in elemental retention on root Fe plaque and their accumulation in various plant parts including grains, specific As uptake (29–167 mg kg?1 dw), as well as As transfer factor (4–45%). Grains retained the least level of As (0.7–3%) with inorganic As species being the dominant forms, while organic As species, viz., dimethylarsinic acid and monomethylarsonic acid, were non-detectable. In all tested varieties, the level of Se was low (0.05–0.12 mg kg?1 dw), whereas that of As was high (0.4–1.68 mg kg?1 dw), considering their safe/recommended daily intake limits, which may not warrant their human consumption. Hence, their utilization may increase the risk of arsenicosis, when grown in As-contaminated areas. 相似文献