全文获取类型
收费全文 | 155篇 |
免费 | 2篇 |
专业分类
化学工业 | 91篇 |
机械仪表 | 3篇 |
能源动力 | 1篇 |
轻工业 | 1篇 |
水利工程 | 4篇 |
一般工业技术 | 3篇 |
冶金工业 | 31篇 |
自动化技术 | 23篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2017年 | 1篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 3篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1990年 | 6篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1969年 | 1篇 |
1960年 | 6篇 |
1959年 | 12篇 |
1958年 | 11篇 |
1957年 | 12篇 |
1956年 | 1篇 |
1955年 | 12篇 |
1953年 | 1篇 |
1948年 | 13篇 |
1947年 | 8篇 |
1946年 | 5篇 |
1945年 | 1篇 |
排序方式: 共有157条查询结果,搜索用时 15 毫秒
121.
122.
Molecular tribology of lubricants and additives 总被引:1,自引:0,他引:1
Knowledge of the bulk viscosity provides little guidance to predict accurately the interfacial shear strength and effective viscosity of a fluid in a lubricated contact. To quantify these differences between bulk and thin-film viscosity, an instrument was developed to measure the shear of parallel single crystal solids separated by molecularly-thin lubricant films. The effective shear viscosity is enhanced compared to the bulk, relaxation times are prolonged, and nonlinear responses set in at lower shear rates. These effects are more prominent, the thinner the liquid film. Studies with lubricant additives cast doubt on the usefulness of the concept of a friction coefficient for lubricated sliding. 相似文献
123.
Universal stress‐sensing dimeric anthracene‐based mechanophore particle fillers incorporated into polyurethane thermoset matrices
下载免费PDF全文
![点击此处可从《Polymer Engineering and Science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Elizabeth M. Nofen Avi Dasgupta Nicholas Zimmer Ryan Gunckel Bonsung Koo Aditi Chattopadhyay Lenore L. Dai 《Polymer Engineering and Science》2017,57(8):901-909
Mechanochemistry, in which mechanical forces induce chemical changes, can allow for targeted damage detection by way of embedded mechanophore units, which emit a measurable signal change correlating to an applied force. In this work, we successfully created stress‐sensing, functional composites by employing microparticles of the mechanophore dimeric 9‐anthracene carboxylic acid in a thermoset polyurethane matrix. The goal being to study the application of the particles as universal stress‐sensing fillers in network polymer matrix composites, after previously evaluating the particles in an epoxy matrix. Under a compressive force, there is bond breakage in the mechanically weak cyclooctane photodimers, such that there is reversion to the fluorescent anthracene‐type monomers. This fluorescent emission was then correlated to the applied strain, and the precursors to damage were detected with a noticeable signal change at a strain of only 2%, which was attributed to increased interactions between the matrix and the particles, with possible surface grafting occurring. This early damage detection was additionally possible at very low particle loadings of 2.5 and 5 wt%, with the 5 wt% loading showing enhanced material properties, due to particle reinforcement. Overall, the stress‐sensitive particle filler allows for facile addition of advanced functionality to these ubiquitous thermoset composites. POLYM. ENG. SCI., 57:901–909, 2017. © 2016 Society of Plastics Engineers 相似文献
124.
Yvonne Rogers Kay Connelly William Hazlewood Lenore Tedesco 《Personal and Ubiquitous Computing》2010,14(2):111-124
Mobile technologies are increasingly being promoted as tools to enhance learning. They can be used to augment ongoing activities,
such as exploring outdoors, by enabling users to move back and forth between the physical environment and a variety of digital
resources and representations. In so doing, they have the potential to facilitate sensemaking activities, where people seek
to find structure in an uncertain situation through using a combination of information, communication and computation. However,
continuous switching of attention between different representations and activities can be distracting. Our research is concerned
with how mobile devices can be used to engender collaborative sensemaking activities during scientific tasks. We present two
studies showing how different versions of a mobile learning application, LillyPad, were used by teams to make sense of their
ongoing observations, when measuring the effects of different planting methods for an environmental restoration site. The
findings show marked differences in the amount and type of sensemaking. We discuss reasons for this in terms of task demands
and workload, information type and distribution of devices. 相似文献
125.
Psychologists around the world have made contributions in research, clinical assessment, and intervention and prevention of domestic violence. Although each country has unique factors that determine the services and resources available to battered women, children exposed to domestic violence, and abusive partners, it is the interaction among gender, political structure, religious beliefs, attitudes toward violence in general, and violence toward women, as well as state-sponsored violence, such as civil conflicts and wars, and the migration within and between countries that ultimately determine women's vulnerability and safety. This article reviews the latest psychological research and applications to intervention and prevention programs. An introduction to the various articles that compose this international perspectives section is also included. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
126.
James E. McGrath Lenore Rasmussen Albert R. Shultz H.K. Shobha M. Sankarapandian Tom Glass Tim E. Long Anthony J. Pasquale 《Polymer》2006,47(11):4042-4057
A novel, high-refractive index homopolymer was produced by incorporating carbazole and phenol into the methacrylate monomer structure. The reaction of phenol with 9-(2,3-epoxypropyl)-carbazole, followed by the reaction of the carbazole phenoxy-based intermediate with methacryloyl chloride or methacrylic anhydride, and recrystallization from methanol, produced a good yield of highly pure carbazole phenoxy functionalized methacrylate monomer. Subsequent free radical polymerization or UV photopolymerization of the functionalized methacrylate monomer, in addition to copolymerizations with methyl methacrylate, provided for high-refractive index materials well suited for lightweight optical applications. Unlike N-vinyl carbazole, the novel carbazole phenoxy-based methacrylate readily copolymerized with methyl methacrylate. Statistical copolymers of carbazole based methacrylates with methyl methacrylate were produced by free radical solution polymerization in DMAC or by photopolymerization in DMF. The carbazole phenoxy-based methacrylate monomer was characterized for molecular weight using gel permeation chromatography (GPC), for melting point and glass transition temperature using differential scanning calorimetry (DSC), for decomposition using thermal gravimetric analysis (TGA), and for chemical composition by one- and two-dimensional 1H nuclear magnetic resonance (NMR) spectroscopy and by elemental analysis. The AIBN initiated carbazole phenoxy-based methacrylate polymerization was followed using in situ FTIR, which showed the reaction to be complete within 40 min in DMAC at 90 °C. Refractive indices of the carbazole based methacrylate homopolymers and copolymers ranged from 1.52 to 1.63. PhotoDSC was used to determine the heat of polymerization (ΔHp) for the carbazole phenoxy-based methacrylate (ΔHp=−39.4 kJ/mol). The carbazole phenoxy-based methacrylate homopolymer had a surprisingly high onset of decomposition temperature (Tonset=316 °C). 13C NMR spectroscopy experiments and molecular modeling were used to explore the configuration of the polymerized carbazole phenoxy-based methacrylate. The lack of head-to-head linkages due to steric considerations reasonably explains the high thermal stability observed for the carbazole phenoxy-based methacrylate polymer. 相似文献
127.
Clark Barrett Benjamin Goldberg Lenore Zuck 《Electronic Notes in Theoretical Computer Science》2003,89(2):89
Translation validation is an approach for validating the output of optimizing compilers. Rather than verifying the compiler itself, translation validation mandates that every run of the compiler generate a formal proof that the produced target code is a correct implementation of the source code. Speculative loop optimizations are aggressive optimizations which are only correct under certain conditions which cannot be validated at compile time. We propose using an automatic theorem prover together with the translation validation framework to automatically generate run-time tests for such speculative optimizations. This run-time validation approach must not only detect the conditions under which an optimization generates incorrect code, but also provide a way to recover from the optimization without aborting the program or producing an incorrect result. In this paper, we apply the run-time validation technique to a class of speculative reordering transformations and give some initial results of run-time tests generated by the theorem prover CVC. 相似文献
128.
Sowmitri Tarimala Neha Kothari Noureddine Abidi Eric Hequet Joe Fralick Lenore L. Dai 《应用聚合物科学杂志》2006,101(5):2938-2943
In this study, cotton fabric was successfully modified to have an antibacterial property through use of the sol–gel process. Dodecanethiol‐capped silver nanoparticles, which have powerful antibacterial activity, were incorporated in silica sol. The starting materials were silver nitrate, tetraoctylammonium bromide, sodium borohydride, chloroform, 1‐dodecanethiol, ethanol, tetraethylorthosilicate, and water. The cotton fabric was padded with dodecanethiol‐capped silver nanoparticle–doped sol, dried at 60°C, and cured at 150°C. Scanning electron microscopy showed a uniform and continuous layer of doped sol on the fiber surface. The antibacterial effects of the treated cotton fabric against Escherichia coli were examined and found to be excellent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101:2938–2943, 2006 相似文献
129.
130.