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91.
Vicky Choi 《Quantum Information Processing》2008,7(5):193-209
We show that the NP-hard quadratic unconstrained binary optimization (QUBO) problem on a graph G can be solved using an adiabatic quantum computer that implements an Ising spin-1/2 Hamiltonian, by reduction through minor-embedding of G in the quantum hardware graph U. There are two components to this reduction: embedding and parameter setting. The embedding problem is to find a minor-embedding G
emb
of a graph G in U, which is a subgraph of U such that G can be obtained from G
emb
by contracting edges. The parameter setting problem is to determine the corresponding parameters, qubit biases and coupler
strengths, of the embedded Ising Hamiltonian. In this paper, we focus on the parameter setting problem. As an example, we
demonstrate the embedded Ising Hamiltonian for solving the maximum independent set (MIS) problem via adiabatic quantum computation
(AQC) using an Ising spin-1/2 system. We close by discussing several related algorithmic problems that need to be investigated
in order to facilitate the design of adiabatic algorithms and AQC architectures. 相似文献
92.
Prof. Dr. Alessio Ciulli Dr. Lawrence Hamann Dr. Wolfgang Jahnke Dr. Amit S. Kalgutkar Prof. Dr. Thomas Magauer Prof. Dr. Tobias Ritter Dr. Vicky Steadman Dr. Scott D. Williams Prof. Dr. Georg Winter Dr. Klemens Hoegenauer Dr. Karl Heinz Krawinkler Dr. Antonia F. Stepan 《ChemMedChem》2021,16(15):2417-2423
The second biannual Alpine Winter Conference on Medicinal and Synthetic Chemistry (short: Alpine Winter Conference) took place January 19–23, 2020, in St. Anton in western Austria. There were roughly 180 attendees from around the globe, making this mid-sized conference particularly conducive to networking and exchanging ideas over the course of four and a half days. This report summarizes the key events and presentations given by researchers working in both industry and academia. 相似文献
93.
Summary. Concurrent systems in which there is a known upper bound Δ on memory access time are considered. Two prototypical synchronization
problems, mutual exclusion and consensus, are studied, and solutions that have constant (i.e. independent of Δ and the total
number of processes) time complexity in the absence of contention are presented. For mutual exclusion, in the absence of contention,
a process needs only five accesses to the shared memory to enter its critical section, and in the presence of contention,
the winning process may need to delay itself for 4 ⋅ Δ time units. For consensus, in absence of contention, a process decides
after four accesses to the shared memory, and in the presence of contention, it may need to delay itself for Δ time units.
Received: July 1993/Accepted: February 1996 相似文献
94.
Associations among parents', teachers', and children's self-reports of internalizing and externalizing child behavior problems were examined in two studies. In the first, both teachers' and parents' reports were modestly and independently associated with children's self-reported behavior problems. In the second, mothers' and fathers' reports of their children's behavior problems were moderately associated with parents' self-reports of their own psychological symptoms as well as with their children's self-reports of their behavior problems. Implications of these studies for the use of multiple perspectives in the assessment of children's behavior problems are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
95.
High-throughput experimentation and screening methods are changing work flows and creating new possibilities in biochemistry, organometallic chemistry, and catalysis. However, many high-throughput systems rely on off-line chromatography methods that shift the bottleneck to the analysis stage. On-line or at-line spectroscopic analysis is an attractive alternative. It is fast, noninvasive, and nondestructive and requires no sample handling. The disadvantage is that spectroscopic calibration is time-consuming and complex. Ideally, the calibration model should give reliable predictions while keeping the number of calibration samples to a minimum. In this paper, we employ the net analyte signal approach to build a calibration model for Fourier transform near-infrared measurements, using a minimum number of calibration samples based on blank samples. This approach fits very well to high-throughput setups. With this approach, we can reduce the number of calibration samples to the number of chemical components in the system. Thus, the question is no longer how many but which type of calibration samples should one include in the model to obtain reliable predictions. Various calibration models are tested using Monte Carlo simulations, and the results are compared with experimental data for palladium-catalyzed Heck cross-coupling. 相似文献
96.
Marios Mavronicolas Vicky Papadopoulou Anna Philippou Paul Spirakis 《Algorithmica》2008,51(3):315-341
Consider an information network with threats called attackers; each attacker uses a probability distribution to choose a node of the network to damage. Opponent to the attackers is a protector entity called defender; the defender scans and cleans from attacks some part of the network (in particular, a link), which it chooses independently using its own probability distribution. Each attacker wishes to maximize the probability
of escaping its cleaning by the defender; towards a conflicting objective, the defender aims at maximizing the expected number
of attackers it catches.
We model this network security scenario as a non-cooperative strategic game on graphs. We are interested in its associated Nash equilibria, where no network entity can unilaterally increase its local objective. We obtain the following results:
A preliminary version of this work appeared in the Proceedings of the 16th Annual International Symposium on Algorithms and
Computation, X. Deng and D. Du, eds., Lecture Notes in Computer Science, vol. 3827, pp. 288–297, Springer, December 2005.
This work has been partially supported by the IST Program of the European Union under contract 001907 (
), and by research funds at University of Cyprus. 相似文献
• | We obtain an algebraic characterization of (mixed) Nash equilibria. | ||||
• | No (non-trivial) instance of the graph-theoretic game has a pure Nash equilibrium. This is an immediate consequence of some covering properties we prove for the supports of the players in all (mixed) Nash equilibria. | ||||
• |
We coin a natural subclass of mixed Nash equilibria, which we call Matching Nash equilibria, for this graph-theoretic game. Matching Nash equilibria are defined by enriching the necessary covering properties we proved
with some additional conditions involving other structural parameters of graphs, such as Independent Sets.
|
97.
Madlensky Lisa; Natarajan Loki; Flatt Shirley W.; Faerber Susan; Newman Vicky A.; Pierce John P. 《Canadian Metallurgical Quarterly》2008,27(5):539
Objective: Little is known about temporal patterns of diet change within interventions, nor about predictors of early and sustained successful change. Social-cognitive theory asserts that early successes in achieving behavior change increase self-efficacy, leading to longer-term success. Design: The authors conducted exploratory cluster analyses using dietary data from the first month of the telephone counseling intervention of the Women's Healthy Eating and Living (WHEL) Study. Main Outcome Measure: Change in dietary pattern at three early intervention timepoints. Results: Three clusters were identified: Cluster 1 (25%) was close to meeting study goals at baseline, but still made major changes; Cluster 2 (49%) and Cluster 3 (26%) were not achieving study goals at baseline, but Cluster 2 made substantial immediate changes, while Cluster 3 changed their diet more gradually. Baseline demographic and behavioral variables were associated with cluster membership; however, the strongest predictors of cluster were self-efficacy, motivation, and approaches to study goals. Cluster membership predicted dietary pattern at 12 months. Conclusion: These data suggest that a one-on-one telephone counseling intervention that is intensive in the early weeks may maximize the level of change achieved in a study. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
98.
Xu J Ishikawa H Wollstein G Kagemann L Schuman JS 《IEEE transactions on medical imaging》2012,31(7):1337-1345
Eye movement artifacts occurring during 3-D optical coherence tomography (OCT) scanning is a well-recognized problem that may adversely affect image analysis and interpretation. A particle filtering algorithm is presented in this paper to correct motion in a 3-D dataset by considering eye movement as a target tracking problem in a dynamic system. The proposed particle filtering algorithm is an independent 3-D alignment approach, which does not rely on any reference image. 3-D OCT data is considered as a dynamic system, while the location of each A-scan is represented by the state space. A particle set is used to approximate the probability density of the state in the dynamic system. The state of the system is updated frame by frame to detect A-scan movement. The proposed method was applied on both simulated data for objective evaluation and experimental data for subjective evaluation. The sensitivity and specificity of the x-movement detection were 98.85% and 99.43%, respectively, in the simulated data. For the experimental data (74 3-D OCT images), all the images were improved after z-alignment, while 81.1% images were improved after x-alignment. The proposed algorithm is an efficient way to align 3-D OCT volume data and correct the eye movement without using references. 相似文献
99.
Endocannabinoids have been implicated in cancer development and cause heterogenous effects in tumor cells, by inducing apoptosis,
reducing migration, causing anti-angiogenic activity and alterations in the cell cycle resulting in growth arrest. Recently,
several novel amides of fatty acids that are structurally related to endocannabinoids have been isolated from mammalian sources,
although the functions of these fatty amides are not well studied. One group of these novel fatty acid amides are the N-acyl taurines (fatty acids conjugated to the amino acid taurine). This study examined if N-acyl taurines, specifically N-arachidonoyl taurine and N-oleoyl taurine could function in a similar way to endocannabinoids and result in cell cycle alterations or growth arrest
in the human prostate adenocarcinoma cell line PC-3. PC-3 cells were treated with various concentrations of N-arachidonoyl taurine and N-oleoyl taurine and cell proliferation and viability was measured using resazurin and colony formation assays. Effects of
N-acyl taurines on the cell cycle was measured using FACS analysis. Treatment with N-arachidonoyl taurine and N-oleoyl taurine resulted in a significant reduction in proliferation of PC-3 cells, even at concentrations as low as 1 μM.
Treatment with N-oleoyl taurine resulted in an increased number of cells in the subG1 population, suggesting apoptosis, and a lower number
of cells in S-phase of the cell cycle. In summary, our results show that novel biologically active lipids, the N-acyl taurines, result in reduced proliferation in PC-3 cells. 相似文献
100.
Carlos Caro K. Thirunavukkarasu M. Anilkumar N. R. Shiju Gadi Rothenberg 《Advanced Synthesis \u0026amp; Catalysis》2012,354(7):1327-1336
We study the selective catalytic oxidation of ethanol with air as a sustainable alternative route to acetaldehyde. The reaction is catalysed by molybdenum oxide supported on titania, in a flow reactor under ambient pressure. High selectivity to acetaldehyde (70%–89%, depending on the Mo loading) is obtained at 150 °C. Subsequently, we investigate the structure/performance relationship for various molybdenum oxide species using a combination of techniques including diffuse reflectance UV‐visible, infrared, X‐ray photoelectron spectroscopies, X‐ray diffraction and temperature programmed reduction. As their surface density increases, the monomeric molybdenum oxide species undergo two‐dimensional and three‐dimensional oligomerisation. This results in polymolybdates and molybdenum oxide crystallites. Importantly, the ethanol oxidation rate depends not only on the overall molybdenum loading and dispersion, but also on the type of molybdenum oxide species prevalent at each surface density and on the domain size. As the molybdenum oxide oligomerisation increases, electron delocalisation becomes easier. This lowers the absorption edge energy and increases the reaction rate. 相似文献