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31.
32.
This paper shows the results of welding tests used so far on high-temperature creep resistant steels and new bainitic and martensitic steels. The positive results of this research allowed the elaboration of a welding procedure specification that was ultimately approved by TÜV. This then allowed the SEFAKO Company to attempt welding of the latest generation boiler steels for use under heavy conditions. 相似文献
33.
Degeneffe Charles Edmund; Chan Fong; Dunlap Laura; Man David; Sung Connie 《Canadian Metallurgical Quarterly》2011,56(3):243
Objective: To use multitrait analysis to determine the measurement structure of the Caregiver Empowerment Scale (CES). Participants: An American sample of 87 adult primary family caregivers of persons with traumatic brain injury (TBI). Results: A four-factor structure was identified including factor 1 (Advocacy Self-Efficacy), factor 2 (Community Self-Efficacy), factor 3 (Caregiver Self-Efficacy), and factor 4 (Personal Self-Efficacy). Conclusions: The CES provides clinicians and researchers a means to assess self-perceived coping abilities of family caregivers of persons with TBI. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
34.
Sagar Chaki Edmund Clarke Joël Ouaknine Natasha Sharygina Nishant Sinha 《Formal Aspects of Computing》2005,17(4):461-483
We present a framework for model checking concurrent software systems which incorporates both states and events. Contrary
to other state/event approaches, our work also integrates two powerful verification techniques, counterexample-guided abstraction
refinement and compositional reasoning. Our specification language is a state/event extension of linear temporal logic, and
allows us to express many properties of software in a concise and intuitive manner. We show how standard automata-theoretic
LTL model checking algorithms can be ported to our framework at no extra cost, enabling us to directly benefit from the large
body of research on efficient LTL verification.
We also present an algorithm to detect deadlocks in concurrent message-passing programs. Deadlock- freedom is not only an
important and desirable property in its own right, but is also a prerequisite for the soundness of our model checking algorithm.
Even though deadlock is inherently non-compositional and is not preserved by classical abstractions, our iterative algorithm
employs both (non-standard) abstractions and compositional reasoning to alleviate the state-space explosion problem. The resulting
framework differs in key respects from other instances of the counterexample-guided abstraction refinement paradigm found
in the literature.
We have implemented this work in the magic verification tool for concurrent C programs and performed tests on a broad set
of benchmarks. Our experiments show that this new approach not only eases the writing of specifications, but also yields important
gains both in space and in time during verification. In certain cases, we even encountered specifications that could not be
verified using traditional pure event-based or state-based approaches, but became tractable within our state/event framework.
We also recorded substantial reductions in time and memory consumption when performing deadlock-freedom checks with our new
abstractions. Finally, we report two bugs (including a deadlock) in the source code of Micro-C/OS versions 2.0 and 2.7, which
we discovered during our experiments.
This research was sponsored by the National Science Foundation (NSF) under grants no. CCR-9803774 and CCR-0121547, the Office
of Naval Research (ONR) and the Naval Research Laboratory (NRL) under contract no. N00014-01-1-0796, the Army Research Office
(ARO) under contract no. DAAD19-01-1-0485, and was conducted as part of the Predictable Assembly from Certifiable Components
(PACC) project at the Software Engineering Institute (SEI).
This article combines and builds upon the papers (CCO+04) and (CCOS04).
Received December 2004
Revised July 2005
Accepted July 2005 by Eerke A. Boiten, John Derrick, Graeme Smith and Ian Hayes 相似文献
35.
Metal–support interactions on supported rhodium catalysts were studied by using specially prepared Rh/TiO2/Mo model systems. For their characterization and the analysis of modifications due to various heat treatments several surface analytical methods were applied: low-energy ion scattering, X-ray photoemission spectroscopy and thermal desorption spectroscopy. Heating in ultrahigh vacuum to 670 K leads to Rh agglomeration followed (above 720 K) by encapsulation including the formation of reduced titanium oxide species. These morphological and chemisorption changes are reversible upon reoxidation and low-temperature reduction and thus exhibit the characteristic features of strong metal–support interactions. For the effective mechanism a reaction is suggested that involves oxygen chemisorption on the Rh clusters and partial reduction of the surrounding support oxide. 相似文献
36.
Conducted 4 experiments with 4 male rhesus monkeys in which food was diverted from the stomach, the small intestine, or both. Results demonstrate that (a) food acting at the pregastric level was not sufficient to produce normal-sized meals, (b) accumulation of food in the small intestine was necessary to produce normal-sized meals, and (c) a potent preabsorptive or postabsorptive satiety signal originated at the intestinal level. It is concluded that this unidentified satiety signal is sufficient to elicit satiety, can be dissociated from gastric emptying, and does not require the presence of gastic distention to operate. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
37.
38.
On-line decision support for take-off runway scheduling with uncertain taxi times at London Heathrow airport 总被引:2,自引:0,他引:2
Jason A. D. Atkin Edmund K. Burke John S. Greenwood Dale Reeson 《Journal of Scheduling》2008,11(5):323-346
This paper addresses the challenge of building an automated decision support methodology to tackle the complex problem faced
every day by runway controllers at London Heathrow Airport. Aircraft taxi from stands to holding areas at the end of the take-off
runway where they wait in queues for permission to take off. A runway controller attempts to find the best order for aircraft
to take off. Sequence-dependent separation rules that depend upon aircraft size, departure route and speed group ensure that
this is not a simple problem to solve. Take-off time slots on some aircraft and the need to avoid excessive delay for any
aircraft make this an even more complicated problem. Making this decision at the holding area helps to avoid the problems
of unpredictable push-back and taxi times, but introduces a number of complex spatial constraints that would not otherwise
exist. The holding area allows some flexibility for interchange of aircraft between queues, but this is limited by its physical
layout. These physical constraints are not usually included in academic models of the departure problem. However, any decision
support system to support the take-off runway controller must include them. We show, in this paper, that a decision support
system could help the controllers to significantly improve the departure sequence at busy times of the day, by considering
the taxiing aircraft in addition to those already at the holding area. However, undertaking this re-introduces the issue of
taxi time uncertainty, the effect of which we explicitly measure in these experiments. Empirical results are presented for
experiments using real data from different times of the day, showing how the performance of the system varies depending upon
the volume of traffic and the accuracy of the provided taxi time estimations. We conclude that the development of a good taxi
time prediction system is key to maximising the benefits, although benefits can be observed even without this. 相似文献
39.
The RCCL model (M. C. Lovett and C. D. Schunn, 1999; see record 1999-05245-001) produces predictions that are non-novel or that do not truly spring from its principles. However, it offers the valuable insight that learning processes may affect the selection of both representations and strategies within those representations, and points the way to possible theoretical progress on implicit and explicit control. The authors' account of base-rate neglect under direct experience is compared with RCCL, and it is concluded that learning-based models allow for tests that are not fostered by representation-based models. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
40.
Dubis Eligiusz Poplawski Janusz Wróbel Jerzy T. Kúsmierz Józef Maliński Edmund Szafranek Janusz 《Lipids》1986,21(7):434-439
The exoskeleton triglyceride fraction isolated from the Colorado beetle,Leptinotarsa decemlineata Say, was studied. Analysis of the hydrolysis products and direct capillary column gas chromatography showed that, apart from
triglycerides, the fraction contained no diol lipids. The composition of the natural triacylglccerol mixture was assessed
by gas chromatography and by field desorption and electron impact mass spectrometry. Triglycerides isolated from the Colorado
beetle are typical glycerol triesters, with long chain (mainly oleic or palmitic) fatty acids. The structures of two major
components (91%), i.e., trioleoyl glycerol and 1,2-dioleoyl-3-palmitoyl glycerol, were determined. 相似文献