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991.
Mahuya?Mukhopadhyay A.?Patra A.?K.?PaulEmail author 《World journal of microbiology & biotechnology》2005,21(5):765-769
Summary Production of poly(3-hydroxybutyric acid) [P(3HB)] by Rhodopseudomonas palustris SP5212 isolated in this laboratory has been optimized under phototrophic microaerophilic conditions. Cells grown in malate medium accumulated 7.7% (w/w) P(3HB) of cellular dry weight at the early stationary phase of growth. The accumulated P(3HB) however, attained 15% (w/w) of cellular dry weight when acetate (1.0%, w/v) was used as the sole carbon source under nitrogen-limiting conditions. Synthesis and accumulation of polymer was favoured by sulphate-free conditions and at a phosphate concentration sub-optimal for growth. The polymer content of cells was increased drastically (34% of cellular dry weight) when the acetate containing medium was supplemented with n-alkanoic acids. Compositional analysis by H1 NMR revealed that these accumulated polymers were composed of 3-hydroxybutyric acid and 3-hydroxyvaleric acid (3HV). The contents of 3HV in these copolymers ranged from 14 to 38 mol%. 相似文献
992.
T.?Premkumar S.?GovindarajanEmail author 《World journal of microbiology & biotechnology》2005,21(4):479-480
Summary Some new hydrazinium salts of 2-pyrazinecarboxylate, 2,3-pyrazinedicarboxylate, 3,5-pyrazoledicarboxylate and 4,5-imidazoledicarboxylate have been prepared. The in vitro antibacterial screening of the free acids and their hydrazinium salts has been carried out against Escherichia coli, Salmonella typhiiand Vibrio cholerae. The antibacterial activities of the prepared hydrazinium salts show more promising activity than the corresponding free acids and the standard positive control antibiotic, Co-trimoxazole. 相似文献
993.
Vegetation analysis and tree population structure of tropical wet evergreen forests in and around Namdapha National Park,northeast India 总被引:1,自引:0,他引:1
P.C.?Nath A.?ArunachalamEmail author M.L.?Khan K.?Arunachalam A.R.?Barbhuiya 《Biodiversity and Conservation》2005,14(9):2109-2135
Species composition, diversity and tree population structure were studied in three stands of the tropical wet evergreen forest in and around Namdapha National Park, Arunachal Pradesh, India. Three study stands exposed to different intensities of disturbances were identified, viz., undisturbed (2.4 ha) in the core zone of the park, moderately disturbed (2.1 ha) in the periphery of the park and highly disturbed (2.7 ha) outside the park area. In total 200 plant species belonging to 73 families were recorded in three stands. Tree density and basal area showed a declining trend with the increase in disturbance intensity. The densities of tree saplings and seedlings were lower in the disturbed stands than in the undisturbed stand. Species like Altingia excelsa, Olea dioica, Terminalia chebula, Mesua ferrea and Shorea assamica in the undisturbed stand and Albizia procera alone in the moderately disturbed stand contributed more than 50% of the total tree density in respective stands. The undisturbed stand contained young tree population. In the highly disturbed stand, the tree density was scarce, but had uncut trees of higher girth class (>210 cm GBH). Low shrub density was recorded in both disturbed stands due to frequent human disturbances; the broken canopy and direct sunlight enhanced the abundance of herbs in these stands. With a species rarity (species having <2 individuals) of ca. 50%, the tropical wet evergreenforests of the Namdapha National Park and its adjacent areas warrant more protection from human intervention and also eco-development to meet the livelihood requirements of the local inhabitants in the peripheral areas of the Namdapha National Park in order to reduce the anthropogenic pressure on the natural resources of the park. 相似文献
994.
Swine and poultry pathogens: the complete genome sequences of two strains of Mycoplasma hyopneumoniae and a strain of Mycoplasma synoviae 总被引:4,自引:0,他引:4
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Vasconcelos AT Ferreira HB Bizarro CV Bonatto SL Carvalho MO Pinto PM Almeida DF Almeida LG Almeida R Alves-Filho L Assunção EN Azevedo VA Bogo MR Brigido MM Brocchi M Burity HA Camargo AA Camargo SS Carepo MS Carraro DM de Mattos Cascardo JC Castro LA Cavalcanti G Chemale G Collevatti RG Cunha CW Dallagiovanna B Dambrós BP Dellagostin OA Falcão C Fantinatti-Garboggini F Felipe MS Fiorentin L Franco GR Freitas NS Frías D Grangeiro TB Grisard EC Guimarães CT Hungria M Jardim SN Krieger MA 《Journal of bacteriology》2005,187(16):5568-5577
This work reports the results of analyses of three complete mycoplasma genomes, a pathogenic (7448) and a nonpathogenic (J) strain of the swine pathogen Mycoplasma hyopneumoniae and a strain of the avian pathogen Mycoplasma synoviae; the genome sizes of the three strains were 920,079 bp, 897,405 bp, and 799,476 bp, respectively. These genomes were compared with other sequenced mycoplasma genomes reported in the literature to examine several aspects of mycoplasma evolution. Strain-specific regions, including integrative and conjugal elements, and genome rearrangements and alterations in adhesin sequences were observed in the M. hyopneumoniae strains, and all of these were potentially related to pathogenicity. Genomic comparisons revealed that reduction in genome size implied loss of redundant metabolic pathways, with maintenance of alternative routes in different species. Horizontal gene transfer was consistently observed between M. synoviae and Mycoplasma gallisepticum. Our analyses indicated a likely transfer event of hemagglutinin-coding DNA sequences from M. gallisepticum to M. synoviae. 相似文献
995.
Background
Signaling pathways include intricate networks of reversible covalent modification cycles. Such multicyclic enzyme cascades amplify the input stimulus, cause integration of multiple signals and exhibit sensitive output responses. Regulation of glycogen synthase and phosphorylase by reversible covalent modification cycles exemplifies signal transduction by enzyme cascades. Although this system for regulating glycogen synthesis and breakdown appears similar in all tissues, subtle differences have been identified. For example, phosphatase-1, a dephosphorylating enzyme of the system, is regulated quite differently in muscle and liver. Do these small differences in regulatory architecture affect the overall performance of the glycogen cascade in a specific tissue? We address this question by analyzing the regulatory structure of the glycogen cascade system in liver and muscle cells at steady state.Results
The glycogen cascade system in liver and muscle cells was analyzed at steady state and the results were compared with literature data. We found that the cascade system exhibits highly sensitive switch-like responses to changes in cyclic AMP concentration and the outputs are surprisingly different in the two tissues. In muscle, glycogen phosphorylase is more sensitive than glycogen synthase to cyclic AMP, while the opposite is observed in liver. Furthermore, when the liver undergoes a transition from starved to fed-state, the futile cycle of simultaneous glycogen synthesis and degradation switches to reciprocal regulation. Under such a transition, different proportions of active glycogen synthase and phosphorylase can coexist due to the varying inhibition of glycogen-synthase phosphatase by active phosphorylase.Conclusion
The highly sensitive responses of glycogen synthase in liver and phosphorylase in muscle to primary stimuli can be attributed to distinctive regulatory designs in the glycogen cascade system. The different sensitivities of these two enzymes may exemplify the adaptive strategies employed by liver and muscle cells to meet specific cellular demands.996.
K.?Jayapaul P.?B.?Kavi?Kishor K.?Janardhan?ReddyEmail author 《In vitro cellular & developmental biology. Plant》2005,41(5):682-685
Summary Callus cultures of Adhatoda zeylanica Medicus were established from leaf and petiole explants. Accumulation of a bioactive pyrroloquinazoline alkaloid, vasicine,
in callus cultures was detected and confirmed by thin layer chromatography, electron-ionization mass spectra, 13C NMR and high-pressure liquid chromatography analysis. The mass of vasicine obtained from leaf-derived callus cultures was
found as 188 and this is comparable to that of the authentic sample. The retention time for leaf-derived extract was 10.065
and for the petiole-derived extract was 9.78 (authentic sample had 9.6 retention time) on high-performance liquid chromatography.
The mass and NMR spectra were compared with the spectra obtained from the authentic sample of vasicine. Different growth regulators
greatly influenced the growth of callus cultures. The accumulation of vasicine was more in leaf-derived callus grown on Murashige
and Skoog (MS) medium with 2.3 μM kinetin, and 4.5 μM 2,4-dichlorophenoxyacetic acid. This is the first report on in vitro production of a pharmacologically important compound vasicine and its characterization by mass spectrometry and 13C NMR studies from callus cultures of Adhatoda zeylanica. 相似文献
997.
Deepak?Prem Kadambari?Gupta Abha?AgnihotriEmail author 《In vitro cellular & developmental biology. Plant》2005,41(3):266-273
Summary The influence of donor plant growth environment, microspore development stage, culture media and incubation conditions on
microspore embryogenesis was studied in three Indian B. juncea varieties. The donor plants were grown under varying environments: field conditions, controlled conditions, or a combination
of the two. The correlation analysis between the bud size and microspore development stage revealed that the bud size is an
accurate marker for donor plants grown under controlled conditions, however, the same does not hold true for the field-grown
plants. The buds containing late uninucleate microspores collected from plants grown under normal field conditions up to bolting
stage and then transferred to controlled environment were observed to be most responsive with genotypic variability ranging
from 10 to 35 embryos per Petri dish, irrespective of the other factors. NLN medium containing 13% sucrose was found to be
most suitable for induction of embryogenesis The fortification of this medium with activated charcoal, polyvinylpyrrolidone,
colchicine, or growth regulators (6-benzylaminopurine and 1-naphthaleneacetic acid) was observed to be antagonistic for microspore
embryogenesis, while silver nitrate (10 μM) had a significant synergistic effect. A post-culture high-temperature incubation of microspores at 32.5±1°C for 10–15 d
was found most suitable for high-frequency production of microspore embryos. The highest frequency of microspore embryogenesis
(78 embryos per Petri dish) was observed from the late uninucleate microspores (contained in bud sizes 3.1–3.5 nm irrespective
of genotype) cultured on NLN medium containing 13% sucrose and silver nitrate (10 μM), and incubated at 32.5°C for 10–15 d. 相似文献
998.
J.?Basak S.?Kundagrami T.?K.?Ghose A.?PalEmail author 《Molecular breeding : new strategies in plant improvement》2005,14(4):375-383
Yellow mosaic virus, YMV, causes one of the most severe of biotic stresses in Vignas, an important group of pulse crops. The viral disease is transmitted through the white fly, Bemicia tabaci, and the yield of the plants is affected drastically. YMV-tolerant lines, generated from a single YMV-tolerant plant identified in the field within a large population of the susceptible cultivar T-9, were crossed with T-9, and F1, F2 and F3 progenies raised. The different generations were phenotyped for YMV-reaction by forced inoculation using viruliferous white flies. A monogenic recessive control of YMV-tolerance was revealed from the F2 segregation ratio of 3:1 (susceptible: tolerant), which was confirmed by the segregation ratio of the F3 families. Of 24 pairs of resistance gene analog (RGA) primers screened, only one pair, RGA 1F-CG/RGA 1R, was found to be polymorphic among the parents. Selected F2 individuals and F3 families were genotyped with the polymorphic RGA primer pair and the polymorphism was found to be linked with YMV-reaction. This primer pair amplified a 445bp DNA fragment only from homozygous tolerant and the heterozygous lines. The 445bp marker band was sequenced and named 'VMYR1'. The predicted amino acid sequence showed highly significant homology with the NB-ARC domain present in several gene products involved in plant disease resistance, nematode cell death and human apoptotic signaling. To the best of our knowledge, this is the first report of YMV-resistance linked DNA marker development in any crop species using segregating populations. This YMV-resistance linked marker is of potential commercial importance in resistance breeding of plants. 相似文献
999.
L-carnitine transport has been measured in enterocytes and basolateral membrane vesicles (BLMV) isolated from chicken intestinal epithelia. In the nominally Na+-free conditions chicken enterocytes take up L-carnitine until the cell to medium L-carnitine ratio is 1. This uptake was inhibited by L-carnitine, D-carnitine, gamma-butyrobetaine, acetylcarnitine, tetraethylammonium (TEA), and betaine. L-3H-carnitine uptake into BLMV showed no overshoot, and it was (i) Na+-independent, (ii) trans-stimulated by intravesicular L-carnitine, and (iii) cis-inhibited by TEA and cold L-carnitine. L-3H-carnitine efflux from L-3H-carnitine preloaded enterocytes was also Na+-independent, and trans-stimulated by L-carnitine, D-carnitine, gamma-butyrobetaine, acetylcarnitine, TEA, and betaine. Both, uptake and efflux of L-carnitine were inhibited by verapamil and unaffected by either extracellular pH or palmitoyl-L-carnitine. RT-PCR with specific primers for the mouse OCTN3 transporter revealed the existence of OCTN3 mRNA in mouse intestine, which was confirmed by in situ hybridization studies. Immunohystochemical analysis showed that OCTN3 protein was mainly associated with the basolateral membrane of rat and chicken enterocytes, whereas OCTN2 was detected at the apical membrane. In conclusion, the results demonstrate for the first time that (i) mammalian small intestine expresses OCTN3 mRNA along the villus and (ii) that OCTN3 protein is located in the basolateral membrane. They also suggest that OCTN3 could mediate the passive, Na+ and pH-independent L-carnitine transport activity measured in the three experimental conditions. 相似文献
1000.
Hatipoğlu A Kanbağli O Balkan J Küçük M Cevikbaş U Aykaç-Toker G Berkkan H Uysal M 《Bioscience, biotechnology, and biochemistry》2004,68(10):2050-2057
Hazelnut oil (HO) is rich in monounsaturated fatty acids and antioxidants. We wanted to investigate the effect of HO on lipid levels and prooxidant-antioxidant status in rabbits fed a high-cholesterol (HC) diet. An HC diet caused significant increases in lipids and lipid peroxide levels in the plasma, liver, and aorta together with histopathological atherosclerotic changes in the aorta. Glutathione levels, glutathione peroxidase, and glutathione transferase activities decreased significantly, but superoxide dismutase activity and vitamin E and C levels remained unchanged in the livers of rabbits following HC diet. HO supplementation reduced plasma, liver, and aorta lipid peroxide levels and aorta cholesterol levels together with amelioration in atherosclerotic lesions in the aortas of rabbits fed an HC diet, without any decreasing effect on cholesterol levels in the plasma or liver. HO did not alter the antioxidant system in the liver in the HC group. Our findings indicate that HO reduced oxidative stress and cholesterol accumulation in the aortas of rabbits fed an HC diet. 相似文献