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71.
Brdjanovic D van Loosdrecht MC Hooijmans CM Alaerts GJ Heijnen JJ 《Biotechnology and bioengineering》1998,60(3):326-332
The methodology for determination of the minimally required aerobic sludge retention time (SRTminaer) in biological phosphorus removal (BPR) systems is presented in this article. Contrary to normal biological conversions, the BPR process is not limited by a SRTmin resulting from the maximum growth rate of the organisms. This is because the aerobic SRT should be long enough to oxidize the amount of poly-hydroxy-alkanoates (PHA) stored in the anaerobic phase. This means that the SRTminaer will primarily depend on the PHA conversion kinetics and the maximal achievable PHA content in the cell (storage capacity). The model for the prediction of the minimally required aerobic SRT as a function of kinetic and process parameters was developed and compared with experimental data used to evaluate several operational aspects of BPR in a sequencing batch reactor (SBR) system. The model was proved as capable of describing them satisfactorily.Copyright 1998 John Wiley & Sons, Inc. 相似文献
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L. Campenni’ B. P. Nobre C. A. Santos A. C. Oliveira M. R. Aires-Barros A. M. F. Palavra L. Gouveia 《Applied microbiology and biotechnology》2013,97(3):1383-1393
Today microalgae represent a viable alternative source for high-value products. The specie Chlorella protothecoides (Cp), heterotrophically grown, has been widely studied and provides a high amount of lutein and fatty acids (FA) and has a good profile for biodiesel production. This work studies carotenoid and FA production by autotrophic grown Cp. Cp was grown until the medium’s nitrogen was depleted, then diluted in NaCl solution, resulting in nutritional, luminosity, and salinity stresses. Different NaCl concentrations were tested (10, 20, 30 g/L) at two different dilutions. After dilution, a color shifting from green to orange-red was noticed, showing carotenoid production. The best production of both carotenoids and FA was attained with a 20 g/L NaCl solution. The total carotenoid content was 0.8 % w/w (canthaxanthin (23.3 %), echinenone (14.7 %), free astaxanthin (7.1 %), and lutein/zeaxanthin (4.1 %)). Furthermore, the total lipid content reached 43.4 % w/w, with a FA composition of C18:1 (33.64 %), C16:0 (23.30 %), C18:2 (11.53 %), and less than 12 % of C18:3, which is needed to fulfill the biodiesel quality specifications (EN 14214). 相似文献
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Long-term pattern of population dynamics in the field vole from central Europe: cyclic pattern with amplitude dampening 总被引:1,自引:0,他引:1
Ana Gouveia Vladimír Bejček Jiří Flousek František Sedláček Karel Šťastný Jan Zima Nigel G. Yoccoz Nils Chr. Stenseth Emil Tkadlec 《Population Ecology》2015,57(4):581-589
The subject of population cycles is regarded as controversial due to a number of unsettled questions such as whether or not cyclic patterns are governed by the same processes at high and low latitudes in Europe. Recent evidence suggests that the dynamics at high and low latitudes share the common temporal pattern of vole dynamics referred to as collapsing population cycles. Despite concurrent interest, the key contention around the causal mechanisms that drive population cycles remains a hot topic in ecology. The aims of this study are to supplement information on the seasonal population dynamics of the field vole Microtus agrestis in the Czech Republic by analysing 25 years of time series data. By applying robust estimation procedures, we estimated several parameters to describe population dynamics, such as population variability, amplitude dampening, cycle period, order of the dynamics and the structure of density dependence. The parameters indicate that field vole dynamics in central Europe are highly variable, cyclic dynamics of order two, with peaks in abundance occurring regularly at intervals of 4–5 years. In addition to exhibiting population cycles, the field vole populations show a pattern of dampened amplitude as observed elsewhere in Europe, including northern latitudes. By analysing temporal trends in seasonal abundances, population growth rates and environmental temperatures, we did not obtain evidence to support the hypothesis that amplitude dampening results from the negative effect of increasingly mild winters on winter population growth rates. 相似文献
77.
Filippe Elias de Freitas Soares José Humberto de Queiroz Jackson Victor de Araújo Paula Viana Queiroz Angélica de Souza Gouveia Emy Hiura 《Biocontrol Science and Technology》2015,25(3):337-344
Nematophagous fungi produce chitinases that may be important in the process of infection of eggs and larvae of nematodes. This study aimed to produce, purify, characterise and test the nematicidal action of extracellular chitinases produced by Monacrosporium thaumasium on Panagrellus redivivus. Mycelia from M. thaumasium were used to inoculate a solid medium for chitinase production. The enzymes were purified using a specific technique of adsorption for chitinases. The chitinase activity was determined at different pHs and temperatures. NF34 produced two distinct chitinases (27 and 30 kDa). After 72 hours, these enzymes provided a significant reduction (80%; p < 0.01) of the number of P. redivivus larvae, compared to control. It was shown that isolate NF34 produced chitinases with nematicidal activity. Thus, other experimental designs on geohelminths or even arthropods that transmit diseases may become a new aspect of the field of study of biological control using predatory nematophagous fungi. 相似文献
78.
Alexandra T P Carvalho Leonor Gouveia Charan Raju Kanna Sebastian K T S W?rml?nder Jamie A Platts Shina Caroline Lynn Kamerlin 《Epigenetics》2014,9(12):1604-1612
We report a series of molecular dynamics (MD) simulations of up to a microsecond combined simulation time designed to probe epigenetically modified DNA sequences. More specifically, by monitoring the effects of methylation and hydroxymethylation of cytosine in different DNA sequences, we show, for the first time, that DNA epigenetic modifications change the molecule''s dynamical landscape, increasing the propensity of DNA toward different values of twist and/or roll/tilt angles (in relation to the unmodified DNA) at the modification sites. Moreover, both the extent and position of different modifications have significant effects on the amount of structural variation observed. We propose that these conformational differences, which are dependent on the sequence environment, can provide specificity for protein binding. 相似文献
79.
Élida J. Gouveia Lidiany D. Cavalcanti Fernanda C. Leal Sarah G.F. Mendes Márcia R. Russo 《Journal of fish biology》2021,98(3):874-877
A total of 122 Patinga specimens were collected from fish farms (P1, P2 and P3), and only those from fish farm P1 were shown to be infected with Echinorhynchus gomesi. In addition, fish in this study were shown to have diets that consisted of 21 different food items, and Notodiaptomus sp. (Copepoda: Calanoida) was identified as a potential intermediate host for E. gomesi. 相似文献
80.
Rhonda C Foley Ling-Ling Gao Andrew Spriggs Lena YC Soo Danica E Goggin Penelope MC Smith Craig A Atkins Karam B Singh 《BMC plant biology》2011,11(1):59