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121.
122.
Partial purification and characterization of cyclic AMP phosphodiesterases from Funaria hygrometrica 总被引:1,自引:0,他引:1
Natural-abundance 13C NMR spectroscopy at 15.04 MHz has been used to examine the effects of pH, calcium, and lanthanide ions on the polypeptide cardiac stimulant Anthopleurin-A in aqueous solution. The carboxyl resonance from the aspartic acid residue not observed in a previous study (R. S. Norton and T. R. Norton, 1979, J. Biol. Chem.254, 10220–10226) has been identified and an apparent pKa of 3.4 obtained. More accurate estimates have been derived for the apparent pKa values of the two histidine residues. Binding of Ca2+ ions has been found by equilibrium dialysis and 13C NMR to be weak (Kd > 0.1 M). The interaction with lanthanide ions is slightly stronger, but binding occurs at the C terminus as well as at a site involving one or both of the aspartate carboxylate groups. These results suggest that possible Anthopleurin-A-induced calcium translocation in the myocardial cell is a secondary effect. The interaction of Anthopleurin-A with lipid monolayers has also been examined. Binding occurs to neutral and zwitterionic lipids, but is stronger with negatively charged lipids, particularly cardiolipin. This interaction is also influenced by the presence of Ca2+ ions. The implications of these results for the mechanism of action of this polypeptide are discussed. 相似文献
123.
Summary Evans' tube and cellophane agar-disc techniques were used to evaluate the colonization capacity of the soil microbes and fungistasis,
respectively. Spore germination ofAlternaria tenuis, Curvularia geniculata, Helminthosporium rostratum andPestalotia sp. was studied on a natural soil.
Aspergillus fumigatus was the pioneer colonizer, followed in the order of decreasing colonizing capacity by,A. flavus, A. niger, A. terreus andPenicillium nigricans. Sensitivity of test spores to soil fungistasis declined in the order,C. geniculata → Pestalotia sp. →A. tenuis → H. rostratum. The fungistatic level of the soil samples decreased gradually from side arms 1 to 7 of the Evans tube, inoculated with unsterilized
soil from one end.
Studies conducted with an inoculum of four soil fungi (A. fumigatus, A. flavus, A. niger, andP. nigricans) as well as those involving fumigation of Evans tube by CS2 also proved the greater colonizing capacity ofA. fumigatus. The level of fungistasis followed closely the colonization pattern of this fungus. When added individually to the soil,
all fungi were able to inhibit spore germination of test fungi to some degree or other. 相似文献
124.
Based on in vitro screening for PGP and anti-mycelial activity against three zoosporic pathogenic oomycetes, Pythium aphanidermatum 123, P. aphanidermatum 4746, and Phytophthora nicotianae 4747, seven bacterial isolates were selected for field trials on tomato and chile to test for plant growth promotion under
natural and artificial disease-infested field sites in both winter and wet seasons. The effectiveness of isolates in the field
trials correlated with the in vitro antagonism screening data. Pseudomonas sp. FQP PB-3, FQA PB-3 and GRP3 showed substantial beneficial effects on plant growth promotion and lowered considerably the incidence of pre- and post-emergence
damping-off in both the crops under various disease scenarios. For example, seed bacterization with these bacterial strains
reduced pre-emergence-damping off by ca. 60–70% in the two natural sites, with and without histories of fungicide use in the
winter season, and to a lesser extent, ca. 20–40%, in the warmer wet (high humidity; 85–92%) season. The suppression efficacy
for post-emergence damping-off was less compared to pre-emergence damping-off although still significant (P > 0.05). Our data unambiguously show that screening of a large number of bacterial pool identifies promising isolates that
show beneficial effects on all stages of plant growth in natural oomycete-infested regimes. 相似文献
125.
Plantago exhibit great deal of differences in the breeding system. The reproductive effort calculated on the basis of, (i) dry biomass
of foliar and floral parts and (ii) seed output-weight (mg) per unit leaf area (cm2), exhibits relation with breeding system. The predominantly inbreeding taxa invest higher reproductive effort compared to
their outbreeding allies. In terms of sex allocation strategies, the outbreeding species like P. lanceolata, P. lagopus invest more to the development of floral features and to male functions. On the contrary, inbreeding species such as P. patagonica, P. drummondii, and P. ovata invest greater resources to the female function.
Received 13 April 1998/ Accepted in revised form 6 November 1998 相似文献
126.
Adem BIC Ahmet AK 《Acta Botanica Sinica》2000,42(8):864-867
Thc pollen grains in the atmosphere of Burdur have been studied for a two-year period(1996through 1997)with a Durham sampler.A total of 11 881 pollen grains belongins to 39 taxa have been identi-fied 相似文献
127.
128.
Serum protein changes in mice treated for varying durations with lead nitrate and subsequently infected with 1000 H. nana eggs were compared with their counterpart controls, only treated and only infected groups. Decreased values of beta and gamma globulins in all the experimental groups along with higher worm recoveries indicate suppression of humoral immune response by lead in association with higher worm recoveries indicate suppression of humoral immune response by lead in association with the cellular components since these globulins are known to contain antibodies. Lead treatment for a duration of 45 days proved to be most effective in suppressing the immune response. 相似文献
129.
Devendra Kumar Choudhary Pavan K. Agarwal Bhavdish N. Johri 《Indian journal of microbiology》2010,50(1):19-26
Community level physiological profiles (CLPPs) have been rarely applied to mushroom compost ecosystem, probably for the lack
of standardized methodology. Recently, however CLPPs have been employed as a tool to investigate the degree of maturity of
compost (Mondini and Insam, 2005, Compost Science and Utilization, 13(1): 27–33). The potential of CLPPs to detect compost
maturity test is considerably significant in that it provides sensitivity and the simplicity of the assay. The aim of this
work was to investigate the maturity of casing that comprised of farm yard manure and spent compost and influence of casing
type on the behaviour of bacterial community during the growth cycle of mushroom Agaricus bisporus (Lange) Imbach employing standardized inoculum density and effects of different data interpretation based on the kinetics
of colour formation. Casing samples of different age were extracted at a particular dilution and then inoculated in 96 well
microtitre plates. Optical density (OD) in well was measured at 590 nm every 24 hours for 5 days. Principal component analysis
(PCA) was performed by employing OD values at fixed average well colour development (AWCD). PCA of fresh samples showed that
classification and ordination of samples according to their age were significant with fixed AWCD. 相似文献
130.
The ability to accurately identify and quantify genetic signatures associated with soft selective sweeps based on patterns of nucleotide variation has remained controversial. We here provide counter viewpoints to recent publications in PLOS Genetics that have argued not only for the statistical identifiability of soft selective sweeps, but also for their pervasive evolutionary role in both Drosophila and HIV populations. We present evidence that these claims owe to a lack of consideration of competing evolutionary models, unjustified interpretations of empirical outliers, as well as to new definitions of the processes themselves. Our results highlight the dangers of fitting evolutionary models based on hypothesized and episodic processes without properly first considering common processes and, more generally, of the tendency in certain research areas to view pervasive positive selection as a foregone conclusion.
“We would not object so strenuously to the adaptationist programme if its invocation, in any particular case, could lead in principle to its rejection for want of evidence. We might still view it as restrictive and object to its status as an argument of first choice. But if it could be dismissed after failing some explicit test, then alternatives would get their chance. Unfortunately, a common procedure among evolutionists does not allow such definable rejection for two reasons. First, the rejection of one adaptive story usually leads to its replacement by another, rather than to a suspicion that a different kind of explanation might be required. Secondly, the criteria for acceptance of a story are so loose that many pass without proper confirmation. Often, evolutionists use consistency with natural selection as the sole criterion and consider their work done when they concoct a plausible story.” - Gould and Lewontin, 1979 [1]相似文献