全文获取类型
收费全文 | 1021篇 |
免费 | 94篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 6篇 |
综合类 | 3篇 |
化学工业 | 519篇 |
金属工艺 | 7篇 |
机械仪表 | 19篇 |
建筑科学 | 29篇 |
能源动力 | 27篇 |
轻工业 | 141篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 79篇 |
一般工业技术 | 171篇 |
冶金工业 | 26篇 |
原子能技术 | 1篇 |
自动化技术 | 84篇 |
出版年
2024年 | 2篇 |
2023年 | 10篇 |
2022年 | 124篇 |
2021年 | 177篇 |
2020年 | 38篇 |
2019年 | 36篇 |
2018年 | 47篇 |
2017年 | 29篇 |
2016年 | 53篇 |
2015年 | 40篇 |
2014年 | 52篇 |
2013年 | 70篇 |
2012年 | 56篇 |
2011年 | 89篇 |
2010年 | 47篇 |
2009年 | 38篇 |
2008年 | 36篇 |
2007年 | 30篇 |
2006年 | 27篇 |
2005年 | 26篇 |
2004年 | 19篇 |
2003年 | 10篇 |
2002年 | 9篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有1116条查询结果,搜索用时 15 毫秒
991.
Christopher M.J. Bennett Andrew J. Patman Chiara Milanese Carol N. Eastwick Gavin S. Walker 《International Journal of Hydrogen Energy》2014
The particle size and shape of commercially available MgH2 have been characterised, together with those of ball milled MgH2. These parameters have then been compared with those obtained for the hydrogenated and dehydrogenated state. In addition, thermal conductivity measurements of each specimen have been made. The results show that significant changes occur upon dehydrogenation, which are contrary to expectation. These changes include an increase in average particle size of 28% post dehydrogenation for as received MgH2, rather than the theorised decrease, and an increase of approximately 300% post dehydrogenation in the ball milled MgH2 sample. The change in thermal conductivity between the two material states is also higher than expected with an average variation of 14% between the samples in the hydrogenated and dehydrogenated states. 相似文献
992.
Hao Ma Francesco Baino Sonia Fiorilli Chiara Vitale Brovarone Barbara Onida 《Journal of the European Ceramic Society》2013,33(9):1535-1543
Al-MCM-41 was incorporated, through a sol–gel based dipping approach, inside a glass–ceramic scaffold belonging to the SiO2–CaO–Na2O–Al2O3 (SCNA) system, to obtain an acidic system with bimodal porosity in the meso- and macro-range. First, SCNA was investigated by means of wide-angle X-ray diffraction (XRD), differential thermal analysis (DTA) and hot stage microscopy (HSM) in order to select the optimal sintering condition to fabricate the macroporous foam-like carrier for Al-MCM-41. Then, Al-MCM-41 was incorporated into the SCNA scaffold; the pH value of Al-MCM-41 synthesis solution, used for the scaffold impregnation process, was shown to be a crucial parameter, on identical scaffold dipping time, to determine the distribution and the stability of the incorporated phase. The systems were characterized by means of XRD, N2 adsorption/desorption, TGA and SEM coupled with EDS.The Al-MCM-41-containing scaffold is active in the acid-catalyzed sucrose hydrolysis, chosen as model reaction, at variance with the scaffold as such. 相似文献
993.
A closed-form solution is obtained to determine the buckling and post-buckling behavior of elastically restrained composite panels under compressive loading. The approach allows to study the response of stiffened panels undergoing local buckling modes, taking into account the restraints provided by the stiffeners to the rotation of the skin edges. The panels are modeled as thin plates referring to Marguerre type equations together with classical lamination theory. The equations are written in non-dimensional form, allowing for the study of a wide class of orthotropic laminates. The problem is formulated in terms of out of plane displacement, represented with a single-mode approximation, and Airy stress function. The compatibility equation is solved exactly, while the method of Galerkin is applied to impose the equilibrium. The buckling load, the out of plane displacement at different load levels, and the post-buckling stiffness are derived and compared with finite element analyses, revealing good accuracy. Sensitivity analyses are also performed obtaining design charts. 相似文献
994.
995.
Giamaica Conti Stefano Tambalo Gino Villetti Silvia Catinella Chiara Carnini Franco Bassani Nicolò Sonato Andrea Sbarbati Pasquina Marzola 《Magma (New York, N.Y.)》2010,23(2):93-101
Purpose
To study the in vivo effect of intratracheal administration of lipopolysaccharide (LPS) in mice by magnetic resonance imaging (MRI) and to investigate the correlation with ex vivo histological evaluation of lung inflammation and oedema. 相似文献996.
997.
Gofferedo de Portu Lorenzo Micele Manuel Alberto Roldán Gutiérrez Leonardo Puppulin Maria Chiara Munisso Cesare Melandri Giuseppe Pezzotti 《Journal of the American Ceramic Society》2008,91(4):1316-1318
A new method for assessing the critical temperature in thermally shocked ceramics is proposed. It is based on the measurement of stress relaxation of residual stresses as a consequence of thermal shock. The change in the stress-field is determined by piezo-spectroscopic technique. The technique is described and the results analyzed. The values obtained are compared with those obtained by the conventional method based on strength degradation measured on test pieces quenched at different temperatures. The agreement among the data is very good. 相似文献
998.
999.
Ai Tran HN Sousa F Moda F Mandal S Chanana M Vimercati C Morbin M Krol S Tagliavini F Legname G 《Nanoscale》2010,2(12):2724-2732
Gold nanoparticles coated with oppositely charged polyelectrolytes, such as polyallylamine hydrochloride and polystyrenesulfonate, were examined for potential inhibition of prion protein aggregation and prion (PrPSc) conversion and replication. Different coatings, finishing with a positive or negative layer, were tested, and different numbers of layers were investigated for their ability to interact and reduce the accumulation of PrPSc in scrapie prion infected ScGT1 and ScN2a cells. The particles efficiently hampered the accumulation of PrPSc in ScN2a cells and showed curing effects on ScGT1 cells with a nanoparticle concentration in the picomolar range. Finally, incubation periods of prion-infected mice treated with nanomolar concentrations of gold nanoparticles were significantly longer compared to untreated controls. 相似文献
1000.
In the past, aligned arrays of carbon nanotubes (CNTs) have been observed to exhibit a foam-like dissipative response in compression, garnering attention for possible mechanical applications. Nanoparticles have previously been integrated with graphitic materials for electrochemical applications. Here, we synthesize nanoparticles of SnO2 and MnO2 in the interstices of aligned arrays of CNTs without altering the ordered structure of the arrays, and we characterize their mechanical response. We report that CNT arrays with embedded particles present superior energy dissipation relative to unmodified CNT arrays. In addition, energy dissipation, strain recovery, and structural failure (observed after repeated loading) depend on particle type (SnO2 versus MnO2). 相似文献