全文获取类型
收费全文 | 241篇 |
免费 | 25篇 |
专业分类
化学工业 | 72篇 |
金属工艺 | 1篇 |
机械仪表 | 3篇 |
建筑科学 | 3篇 |
能源动力 | 12篇 |
轻工业 | 54篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 16篇 |
一般工业技术 | 52篇 |
冶金工业 | 18篇 |
原子能技术 | 1篇 |
自动化技术 | 32篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 15篇 |
2021年 | 16篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 12篇 |
2014年 | 7篇 |
2013年 | 22篇 |
2012年 | 20篇 |
2011年 | 25篇 |
2010年 | 17篇 |
2009年 | 13篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有266条查询结果,搜索用时 421 毫秒
31.
32.
Erchul William P.; Scott Susan S.; Dombalis Amelia O.; Schulte Ann C. 《Canadian Metallurgical Quarterly》1989,4(2):103
A national sample of 251 1st- and 2nd-yr doctoral students in school psychology responded to a questionnaire measuring demographic characteristics, preferences among applied specialties in professional psychology, graduate program applications, anticipated internship setting, preferred client population, personal interests, professional goals, and satisfaction with current training. Survey responses showed a clear preference for working directly with children and adolescents following graduation, a high degree of correspondence between training program emphases and student interests and goals, and a moderate degree of student satisfaction with training experiences. Results are interpreted with respect to training trends and standards in school psychology, the relationship between school and clinical psychology, satisfaction of students in clinical and counseling psychology programs, and methodology limitations. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
33.
The effect of different germination conditions, namely, germination time and total presence or absence of light, on the content of the various nitrogen fractions, three essential protein amino acids (Lys, His, and Tyr) and one non-protein amino acid (Orn), was studied in peas, beans, and lentils. The influence of light during germination on the parameters considered varied according to the legume but on the whole was less important than the influence of germination time in quantitative terms. In all three legumes, prolonging the germination time yielded flours that contained more non-protein nitrogen (NPN) and Orn and less protein nitrogen (PN) and Lys, while the changes in the His and Tyr contents varied with legume type. In addition, changes in the Lys, Tyr, and Orn contents correlated with the changes in the NPN and PN levels in the germinated legumes. 相似文献
34.
Bulk and interfacial viscoelasticity in concentrated emulsions: The role of the surfactant 总被引:1,自引:0,他引:1
Miguel Wulff-Pérez Amelia Torcello-GómezAntonio Martín-Rodríguez María J. Gálvez-RuizJuan de Vicente 《Food Hydrocolloids》2011
The aim of this study was to investigate and compare bulk and interfacial viscoelasticity of emulsions stabilized with two surfactants of a markedly different nature: the ionic phospholipids mixture Epikuron 145V and the steric emulsifier Pluronic F68. Emulsions of olive oil in water were prepared by high-pressure homogenization using only one of these surfactants. The impact of the surfactant used on the final linear viscoelastic properties was investigated by means of small-amplitude dynamic oscillatory shear tests, obtaining the values of the storage and loss moduli as a function of frequency, as well as by retardation and relaxation essays. Our results show that for concentrated emulsions, the viscoelastic properties are considerably different depending on which surfactant is used, i.e., the employed surfactant influences to a major extent the bulk rheological properties. In order to explain these differences, an interfacial study of the adsorbed surfactant layers has been carried out, measuring interfacial tension and dilatational viscoelasticity by means of the pendant drop technique. A correlation between the results obtained in bulk and interface has been found. 相似文献
35.
Bárbara E. Meza Amy K.S. ChestertonRoxana A. Verdini Amelia C. RubioloPeter A. Sadd Geoff D. MoggridgeD. Ian Wilson 《Journal of food engineering》2011,104(4):592-602
The rheological behaviour of high ratio cake batters prepared with untreated and heat-treated wheat flours was analysed at different stages of the manufacturing process, namely slurry, (on aeration) foams and (with fat addition) aerated emulsions, featuring air volume fractions up to 0.50. Both steady shear and viscoelastic behaviours were studied. All materials exhibited shear-thinning behaviour at 20 °C over the shear rate range studied (0.07-10 s−1). The generalised Cox-Merz rule could be applied to all samples. Materials prepared with heat-treated flours exhibited greater stability, as indicated by slurry thixotropy and cohesive energy, and the change in apparent viscosity and air content of foams and aerated emulsions on extended mixing. Foams and aerated emulsions showed significant elastic behaviour with G′∼G″. The temperature dependency of aerated emulsions was studied by oscillatory shear testing from 20 to 100 °C and indicated three regimes in temperature dependence: below 40 °C G′and G″ were insensitive to temperature; between 40 and 70 °C the complex viscosity exhibited Arrhenius-type behaviour, while above 70 °C G′ and G″ increased as expected for gelatinisation and foam setting. The weak gel model for foods was used to analyse the latter data sets and confirmed that the gel network generated in aerated emulsions prepared with heat-treated flours was significantly stronger than those made with unheated flours. The differences between flour types were also observed in tests on un- and heat-treated flours obtained from a second and third harvest. The impact of these quantifiable differences in rheology on performance during baking is discussed. 相似文献
36.
Khalili Amelia Ahmad Mohamed Zaharuddin Basri Mohd Ariffanan Mohd 《Microsystem Technologies》2019,25(10):3765-3777
Microsystem Technologies - In this paper a robust backstepping sliding mode controller is developed for tracking control of 2-DOF piezo-actuated micromanipulation system. The control approach is... 相似文献
37.
Abdullah H. Alshehri Kissan Mistry Viet Huong Nguyen Khaled H. Ibrahim David Muoz‐Rojas Mustafa Yavuz Kevin P. Musselman 《Advanced functional materials》2019,29(7)
A quantum‐tunneling metal‐insulator‐metal (MIM) diode is fabricated by atmospheric pressure chemical vapor deposition (AP‐CVD) for the first time. This scalable method is used to produce MIM diodes with high‐quality, pinhole‐free Al2O3 films more rapidly than by conventional vacuum‐based approaches. This work demonstrates that clean room fabrication is not a prerequisite for quantum‐enabled devices. In fact, the MIM diodes fabricated by AP‐CVD show a lower effective barrier height (2.20 eV) at the electrode–insulator interface than those fabricated by conventional plasma‐enhanced atomic layer deposition (2.80 eV), resulting in a lower turn on voltage of 1.4 V, lower zero‐bias resistance, and better asymmetry of 107. 相似文献
38.
Mathias Uller Rothmann Wei Li Ye Zhu Amelia Liu Zhiliang Ku Udo Bach Joanne Etheridge Yi‐Bing Cheng 《Advanced materials (Deerfield Beach, Fla.)》2018,30(25)
Organic–inorganic hybrid perovskites, such as CH3NH3PbI3, have shown highly promising photovoltaic performance. Electron microscopy (EM) is a powerful tool for studying the crystallography, morphology, interfaces, lattice defects, composition, and charge carrier collection and recombination properties at the nanoscale. Here, the sensitivity of CH3NH3PbI3 to electron beam irradiation is examined. CH3NH3PbI3 undergoes continuous structural and compositional changes with increasing electron dose, with the total dose, rather than dose rate, being the key operative parameter. Importantly, the first structural change is subtle and easily missed and occurs after an electron dose significantly smaller than that typically applied in conventional EM techniques. The electron dose conditions under which these structural changes occur are identified. With appropriate dose‐minimization techniques, electron diffraction patterns can be obtained from pristine material consistent with the tetragonal CH3NH3PbI3 phases determined by X‐ray diffraction. Radiation damage incurred at liquid nitrogen temperatures and using Ga+ irradiation in a focused ion beam instrument are also examined. Finally, some simple guidelines for how to minimize electron‐beam‐induced artifacts when using EM to study hybrid perovskite materials are provided. 相似文献
39.
Tuning the Molecular Weight of the Electron Accepting Polymer in All‐Polymer Solar Cells: Impact on Morphology and Charge Generation
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Rukiya Matsidik Shyamal K. K. Prasad Luke A. Connal Amelia C. Y. Liu Lars Thomsen Justin M. Hodgkiss Christopher R. McNeill 《Advanced functional materials》2018,28(18)
Molecular weight is an important factor determining the morphology and performance of all‐polymer solar cells. Through the application of direct arylation polycondention, a series of batches of a fluorinated naphthalene diimide‐based acceptor polymer are prepared with molecular weight varying from Mn = 20 to 167 kDa. Used in conjunction with a common low bandgap donor polymer, the effect of acceptor molecular weight on solar cell performance, morphology, charge generation, and transport is explored. Increasing the molecular weight of the acceptor from Mn = 20 to 87 kDa is found to increase cell efficiency from 2.3% to 5.4% due to improved charge separation and transport. Further increasing the molecular weight to Mn = 167 kDa however is found to produce a drop in performance to 3% due to liquid–liquid phase separation which produces coarse domains, poor charge generation, and collection. In addition to device studies, a systematic investigation of the microstructure and photophysics of this system is presented using a combination of transmission electron microscopy, grazing‐incidence wide‐angle X‐ray scattering, near‐edge X‐ray absorption fine‐structure spectroscopy, photoluminescence quenching, and transient absorption spectroscopy to provide a comprehensive understanding of the interplay between morphology, photophysics, and photovoltaic performance. 相似文献
40.
Abazović ND Montone A Mirenghi L Janković IA Comor MI 《Journal of nanoscience and nanotechnology》2008,8(2):613-618
In this study, nitrogen-doped titanium dioxide (TiO2) powders were synthesized in two ways: by heating of titanium hydroxide with urea and by direct hydrolysis of titanium tetraisopropoxide (TTIP) with ammonium hydroxide. The samples were characterized by structural (XRD), analytical (XPS), optical (UV/Vis absorption/reflection and Raman spectroscopy) and morphological (SEM, TEM) techniques. The characterization suggested that the doped materials have anatase crystalline form without any detectable peaks that correspond to dopants. The absorption threshold of titanium dioxide was moved in the visible range of optical spectrum from 3.2 eV to 2.20 eV. Particle sizes of synthesized powders were obtained from XRD measurements and from TEM data ranging from 6-20 nm. XPS and Raman spectroscopy were used for detection of nitrogen in doped samples. 相似文献