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High temperature pyrolysis of novolac resin biomass composites 总被引:1,自引:0,他引:1
Johannis Simitzis 《Journal of Analytical and Applied Pyrolysis》1994,30(2):161-171
Composites of novolac resin (N.R.) and biomass derived from olive stones (OL.B.), in various proportions, were cured with hexamethylenetetramine (HTA) and pyrolyzed up to 900°C. The pyrolysis mechanism was monitored using TGA and gas chromatography. The pyrolysis regions, as well as important pyrolysis parameters of the materials used, were determined. Cured and pyrolyzed composites of N.R./OL.B. varied from 20/80 to 75/25, exhibiting at temperatures up to approx. 600°C lower weight losses than expected by the rule of mixtures, owing to additional cross linkages of lignin with HTA. This stabilization effect vanished during pyrolysis at higher temperatures because of the breaking of other chemical bonds, e.g. cross linkages. The release of CH4 during the pyrolysis of OL.B. is derived from the lignin contained in OL.B. The other gases, CO, CO2 and H2, could be formed from celluose, hemicellulose and lignin which are the main components of OL.B. The use of N.R. in the initial mixture with OL.B. reduces the weight losses during pyrolysis compared with OL.B. alone. A heating rate of 10°C/min was necessary for the carbonization processes of OL.B. and its mixtures with N.R. in order to promote minimum weight loss of material and minimum pyrolysis time. 相似文献
676.
The most accurate and up-to-date approach to modeling biomass pyrolysis is to adopt the distributed activation energy model
(DAEM). In this study, a pattern search method to be used for the determination of DAEM kinetic parameters from the nonisothermal
thermogravimetric analysis (TGA) data of biomass has been introduced. The method has been applied to the nonisothermal TGA
data of peanut shell sample, and DAEM kinetic parameters of biomass samples have been determined. Calculated model results
from determined kinetic parameters have been compared with nonisothermal TGA data of biomass. 相似文献
677.
Erika Mészáros Emma Jakab G. Várhegyi P. Tóvári 《Journal of Thermal Analysis and Calorimetry》2007,88(2):477-482
The aim of this work was to study the thermal
decomposition of different plant species obtained from energy plantations.
Thermogravimetry/ mass spectrometry (TG/MS) experiments have been performed
with two herbaceous crops (Miscanthus sinensis,
pelletized energy grass) and two wood samples (willow, water locust) in inert
and oxidative atmospheres. Owing to the large number of data obtained in the
experiments, a chemometric tool, principal component analysis (PCA) has been
used to help the interpretation of the results. It has been found that the
thermal decomposition of the studied wood species is similar, whereas that
of the studied herbaceous samples exhibits significant differences. PCA has
been found to be useful for finding correlations between the various experimental
data. 相似文献
678.
生物质热解、加氢热解及其与煤共热解的热重研究 总被引:36,自引:3,他引:36
在加压热天平上用非等温热重法进行生物质(锯末、稻壳)在N2气氛下的热解和加氢热解研究。考察了升温速率(5~25℃/min)和压力(0.1~7MPa)的影响,求取了热解动力学参数,并研究了生物质与煤在常压N2气下的共热解过程。研究结果表明:生物质在400℃左右即完成热解反应,总失重率大于70%(W%,daf.),热解时仅一个峰位于300℃左右;与煤热解行为相同,随升温速率及压力的升高,转化率下降,DTG峰移向高温,但由于热解反应在较低温度下进行,氧气的存在对生物质热解TG和DTG的影响远小于煤热解。证明生物质热解以其内部氢对自由基的饱和及分子重排反应为主。生物质热解可用一级反应动力学处理,主要热解阶段及表现活化能分别为:锯末,267~314℃,69.66kJ/mol;稻壳,283~310℃,53.45kJ/mol;生物质由于与煤的热分解温度相差很大,因而在其共热解过程中无协同作用。 相似文献
679.
A thermochemical pretreatment of bagasse for the enzymatic hydrolysis has been carried out, in which pretreatment bagasse
was autoclaved with binary solvent, composed of Water and organic solvent having upper critical temperature (UCT) on the mutual
solubility curve. The pretreatment was named “UCT-solvent pretreatment.” The hydrophobic decomposition products from lignin
and hemicellulose, that dissolved in organic phase at room temperature, could be easily separated from the solid and sugars
in the aqueous phase. By using UCT-solvent instead of only water, the sugar recoveries from bagasse through the pretreatment
and the enzymatic hydrolysis were much improved. There exists an optimal mixing ratio between organic solvent and water to
maximize the effect of the pretreatment for enzymatic hydrolysis. The optimal ratio can be explained by the competitive effect
between the ability of water as a reagent for the hydrolysis and the ability of solvent for the extraction of the decomposition
product, and furthermore by the competitive effect between affinities of the solvent to hydrophilic hemicellulose and hydrophobic
lignin. Decomposition of hemicellulose at lower temperature than 190°C was decreased, and hence the degradation of xylose
during the pretreatment decreased. These favorable effects of UCT-solvent pretreatment are significantly attributed to the
formation of the homogeneous single phase of organic solvent and water at high temperature and the phase separation at room
temperature. 相似文献
680.
秸秆发酵燃料乙醇关键问题及其进展 总被引:2,自引:0,他引:2
利用木质纤维素原料生产燃料乙醇是国际公认的难题.本文从秸秆原料组分不均一性出发,分析了秸秆难以高值化原因;进一步分析了秸秆酶解发酵燃料乙醇的关键问题,介绍了有关秸秆原料预处理、纤维素酶生产、秸秆酶解发酵乙醇和产业化示范工程等的进展.秸秆酶解发酵燃料乙醇产业化示范工程具有自主知识产权,为实现我国秸秆转化燃料乙醇的规模化、产业化、低成本生产奠定了基础. 相似文献