全文获取类型
收费全文 | 171篇 |
免费 | 5篇 |
专业分类
化学工业 | 45篇 |
机械仪表 | 1篇 |
建筑科学 | 7篇 |
轻工业 | 30篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 7篇 |
一般工业技术 | 24篇 |
冶金工业 | 42篇 |
自动化技术 | 17篇 |
出版年
2023年 | 1篇 |
2022年 | 10篇 |
2021年 | 9篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 6篇 |
2011年 | 18篇 |
2010年 | 7篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 15篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有176条查询结果,搜索用时 15 毫秒
81.
Bio-Molecular Computing (BMC) has been rapidly evolving as an independent field at the interface between computer science, mathematics, chemistry, and biology. Over the years, numerous architectures of autonomous molecular computing devices have been developed in the lab on the basis of opportunities offered by molecular biology techniques. This account focuses mainly on the realization of programmable DNA-based finite-state automata that can compute autonomously upon mixing all their components in solution.The main advantage of autonomous BMC devices over electronic computers arises from their ability to interact directly with biological systems and even with living organisms without any interface. Indeed, it has been demonstrated that appropriately designed computing machines can produce output signals in the form of a specific biological function via direct interaction with living cells. Additional topics are briefly included to point at interesting opportunities in the field and to describe some of the potential applications and extension of the basic concepts. These include logic evaluators and logic gates that operate in cells, applications in developmental biology, as well as chemical encoding and processing of alphanumeric information. 相似文献
82.
83.
The processing of noun-phrase (NP) anaphors in discourse is argued to reflect constraints on the activation and processing of semantic information in working memory. The proposed theory views NP anaphor processing as an optimization process that is based on the principle that processing cost, defined in terms of activating semantic information, should serve some discourse function—identifying the antecedent, adding new information, or both. In a series of 5 self-paced reading experiments, anaphors' functionality was manipulated by changing the discourse focus, and their cost was manipulated by changing the semantic relation between the anaphors and their antecedents. The results show that reading times of NP anaphors reflect their functional justification: Anaphors were read faster when their cost had a better functional justification. These results are incompatible with any theory that treats NP anaphors as one homogeneous class regardless of discourse function and processing cost. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
84.
85.
Field Tiffany; Greenwald Paul; Morrow Connie; Healy Brian; Foster Tamar; Guthertz Moshe; Frost Patricia 《Canadian Metallurgical Quarterly》1992,28(2):242
Face-to-face interactions of 56 6th-grade friend and acquaintance pairs were videotaped, heart rate was recorded, and saliva cortisol was sampled. During interactions the friend dyads were more attentive, affectively positive, vocal, active, involved, relaxed, and playful, and their cortisol values suggested lower stress levels. They also spent more time together in mutually interested and animated states, and they assigned higher ratings to liking their interactions and interaction partners. Greater coherence in the friend pairs' behavior states and in the acquaintance pairs' vocal activity suggested that the friend pairs more often shared the same behavior state (e.g., playful), and the acquaintance pairs more often paid attention to each others' turn-taking signals, so that when one person talked, the other was silent. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
86.
Mattle MJ Crouzy B Brennecke M Wigginton KR Perona P Kohn T 《Environmental science & technology》2011,45(18):7710-7717
Viruses in wastewater and natural environments are often present as aggregates. The disinfectant dose required for their inactivation, however, is typically determined with dispersed viruses. This study investigates how aggregation affects virus inactivation by chemical disinfectants. Bacteriophage MS2 was aggregated by lowering the solution pH, and aggregates were inactivated by peracetic acid (PAA). Aggregates were redispersed before enumeration to obtain the residual number of individual infectious viruses. In contrast to enumerating whole aggregates, this approach allowed an assessment of disinfection efficiency which remains applicable even if the aggregates disperse in post-treatment environments. Inactivation kinetics were determined as a function of aggregate size (dispersed, 0.55 and 0.90 μm radius) and PAA concentration (5-103 mg/L). Aggregation reduced the apparent inactivation rate constants 2-6 fold. The larger the aggregate and the higher the PAA concentration, the more pronounced the inhibitory effect of aggregation on disinfection. A reaction-diffusion based model was developed to interpret the experimental results, and to predict inactivation rates for additional aggregate sizes and disinfectants. The model showed that the inhibitory effect of aggregation arises from consumption of the disinfectant within the aggregate, but that diffusion of the disinfectant into the aggregates is not a rate-limiting factor. Aggregation therefore has a large inhibitory effect if highly reactive disinfectants are used, whereas inactivation by mild disinfectants is less affected. Our results suggest that mild disinfectants should be used for the treatment of water containing viral aggregates. 相似文献
87.
Time steps for explicit MPM simulation in computer graphics are often selected by trial and error due to the challenges in automatically selecting stable time step sizes. Our time integration scheme uses time step restrictions that take into account forces, collisions, and even grid-to-particle transfers calculated near the end of the time step. We propose a novel set of time step restrictions that allow a time step to be selected that is stable, efficient to compute, and not too far from optimal. We derive the general solution for the sound speed in nonlinear isotropic hyperelastic materials, which we use to enforce the classical CFL time step restriction. We identify a single-particle instability in explicit MPM integration and propose a corresponding time step restriction in the fluid case. We also propose a reflection-based boundary condition for domain walls that supports separation and accurate Coulomb friction while preventing particles from penetrating the domain walls. 相似文献
88.
Oded Zimron Tamar Zilberman Sunil R. Kadam Sirshendu Ghosh Shay-Lee Kolatker Alevtina Neyman Ronen Bar-Ziv Maya Bar-Sadan 《Israel journal of chemistry》2020,60(5-6):624-629
Transition metal dichalcogenides (TMDCs) based materials are considered as highly active alternatives to the precious Pt-based catalysts for the hydrogen evolution reaction (HER). In particular, MoSe2 emerges as a promising catalyst due to its abundance and electrochemical stability, but further modifications are still required to enhance its performance, specifically in alkaline conditions. Here, we developed a method to obtain MoSe2 with two cobalt doping patterns: homogeneously doped and edge doped nanoflowers, with abundant edge sites and extended surface area. The results show that low concentration of doping enhances the catalytic activity toward HER. Incorporation of cobalt as a substituent dopant within the layered structure of MoSe2 appears to have two major contributions: it changes the chemical environment providing more active sites with favored hydrogen adsorption properties, and improves the charge transfer resistance and thus facilitates the HER kinetics. Moreover, the homogeneous and edge-doped nanoflowers show different pH-dependence of HER activity. Edge-doped samples exhibit significantly improved performance in acidic medium, while the overpotential increases in alkaline environment upon doping. A mechanistic explanation of the observed effect is proposed. This work opens up an additional path for improving the catalytic activity of TMDCs in acidic or alkaline medium using a simple and facile method with only small quantities of dopants. 相似文献
89.
Gollan Tamar H.; Slattery Timothy J.; Goldenberg Diane; Van Assche Eva; Duyck Wouter; Rayner Keith 《Canadian Metallurgical Quarterly》2011,140(2):186
To contrast mechanisms of lexical access in production versus comprehension we compared the effects of word frequency (high, low), context (none, low constraint, high constraint), and level of English proficiency (monolingual, Spanish–English bilingual, Dutch–English bilingual) on picture naming, lexical decision, and eye fixation times. Semantic constraint effects were larger in production than in reading. Frequency effects were larger in production than in reading without constraining context but larger in reading than in production with constraining context. Bilingual disadvantages were modulated by frequency in production but not in eye fixation times, were not smaller in low-constraint contexts, and were reduced by high-constraint contexts only in production and only at the lowest level of English proficiency. These results challenge existing accounts of bilingual disadvantages and reveal fundamentally different processes during lexical access across modalities, entailing a primarily semantically driven search in production but a frequency-driven search in comprehension. The apparently more interactive process in production than comprehension could simply reflect a greater number of frequency-sensitive processing stages in production. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
90.
We extend the concepts of phase, polarization, and feedback control of matter to develop a general approach for guiding light in the nanoscale via nanoparticle arrays. The phase and polarization of the excitation source are first introduced as tools for control over the pathway of light at array intersections. Genetic algorithms are next applied as a systematic design tool, wherein both the excitation field parameters and the structural parameters of the nanoparticle array are optimized to make devices with desired functionality. Implications to research fields such as single molecule spectroscopy, spatially confined chemistry, optical logic, and nanoscale sensing are envisioned. 相似文献