全文获取类型
收费全文 | 3679篇 |
免费 | 272篇 |
国内免费 | 24篇 |
专业分类
电工技术 | 52篇 |
综合类 | 20篇 |
化学工业 | 957篇 |
金属工艺 | 68篇 |
机械仪表 | 79篇 |
建筑科学 | 132篇 |
矿业工程 | 9篇 |
能源动力 | 129篇 |
轻工业 | 500篇 |
水利工程 | 46篇 |
石油天然气 | 28篇 |
武器工业 | 2篇 |
无线电 | 323篇 |
一般工业技术 | 476篇 |
冶金工业 | 548篇 |
原子能技术 | 17篇 |
自动化技术 | 589篇 |
出版年
2024年 | 7篇 |
2023年 | 33篇 |
2022年 | 96篇 |
2021年 | 173篇 |
2020年 | 106篇 |
2019年 | 110篇 |
2018年 | 139篇 |
2017年 | 136篇 |
2016年 | 147篇 |
2015年 | 114篇 |
2014年 | 141篇 |
2013年 | 255篇 |
2012年 | 179篇 |
2011年 | 239篇 |
2010年 | 158篇 |
2009年 | 168篇 |
2008年 | 159篇 |
2007年 | 163篇 |
2006年 | 131篇 |
2005年 | 100篇 |
2004年 | 89篇 |
2003年 | 102篇 |
2002年 | 102篇 |
2001年 | 57篇 |
2000年 | 46篇 |
1999年 | 43篇 |
1998年 | 179篇 |
1997年 | 113篇 |
1996年 | 109篇 |
1995年 | 58篇 |
1994年 | 43篇 |
1993年 | 52篇 |
1992年 | 17篇 |
1991年 | 17篇 |
1990年 | 15篇 |
1989年 | 13篇 |
1988年 | 10篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 16篇 |
1984年 | 5篇 |
1983年 | 8篇 |
1982年 | 4篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1977年 | 12篇 |
1976年 | 22篇 |
1971年 | 7篇 |
排序方式: 共有3975条查询结果,搜索用时 15 毫秒
71.
Bill Moran Du Q. Huynh Xuezhi Wang Michael Edwards Andrew Harris Barbara F. La Scala 《Digital Signal Processing》2009,19(5):793-808
We describe here a method for the analysis of materials on a conveyor belt using the natural gamma spectra collected with a BGO (Bismuth Germanate) gamma ray detector. This detector collects gamma ray emissions from the Potassium (K), Uranium (U), and Thorium (Th) atoms in the materials. Based on these data, and using a Poisson model for the data generation, a statistical model is proposed and an approximate maximum likelihood (ML) technique based on the expectation-maximization (EM) algorithm is then used to estimate the amount of each of the three elements in the material. The statistical model is further refined to incorporate parameters of drift in the detector and an estimation technique for this is developed and tested against real data. The Cramér–Rao lower bounds for the estimators are calculated. 相似文献
72.
Leonid B. Freidovich Pedro La Hera Uwe Mettin Anders Robertsson Anton S. Shiriaev Rolf Johansson 《Asian journal of control》2009,11(5):548-556
We consider an underactuated two‐link robot called the inertia wheel pendulum. The system consists of a free planar rotational pendulum and a symmetric disk attached to its end, which is directly controlled by a DC‐motor. The goal is to create stable oscillations of the pendulum, which is not directly actuated. We exploit a recently proposed feedback‐control design strategy based on motion planning via virtual holonomic constraints. This strategy is shown to be useful for design of regulators for achieving orbitally exponentially stable oscillatory motions. The main contribution is a step‐by‐step procedure on how to achieve oscillations with pre‐specified amplitude from a given range and an arbitrary independently chosen period. The theoretical results are verified via experiments with a real hardware setup. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society 相似文献
73.
Marcello La Rosa Wil M. P. van der Aalst Marlon Dumas Arthur H. M. ter Hofstede 《Software and Systems Modeling》2009,8(2):251-274
Variability management is a recurrent issue in systems engineering. It arises for example in enterprise systems, where modules
are configured and composed to meet the requirements of individual customers based on modifications to a reference model.
It also manifests itself in the context of software product families, where variants of a system are built from a common code
base. This paper proposes an approach to capture system variability based on questionnaire models that include order dependencies
and domain constraints. The paper presents analysis techniques to detect circular dependencies and contradictory constraints
in questionnaire models, as well as techniques to incrementally prevent invalid configurations by restricting the space of
allowed answers to a question based on previous answers. The approach has been implemented as a toolset and has been used
in practice to capture configurable process models for film post-production.
相似文献
Arthur H. M. ter HofstedeEmail: |
74.
Cáceres-Criado Irene García-Molina Diego Francisco Mesas-Carrascosa Francisco Javier Triviño-Tarradas Paula 《Virtual Reality》2023,27(2):967-983
Virtual Reality - Virtual reconstruction is defined as the visual recovery of a building or object through the creation of a three-dimensional model of the asset to be reconstructed, in a... 相似文献
75.
Journal of Intelligent Information Systems - Offline evaluation of recommender systems (RSs) mostly relies on historical data, which is often biased. The bias is a result of many confounders that... 相似文献
76.
Diego Canales Adrien Leygue Francisco Chinesta David González Elías Cueto Eric Feulvarch Jean‐Michel Bergheau Antonio Huerta 《International journal for numerical methods in engineering》2016,108(9):971-989
This paper proposes a generalized finite element method based on the use of parametric solutions as enrichment functions. These parametric solutions are precomputed off‐line and stored in memory in the form of a computational vademecum so that they can be used on‐line with negligible cost. This renders a more efficient computational method than traditional finite element methods at performing simulations of processes. One key issue of the proposed method is the efficient computation of the parametric enrichments. These are computed and efficiently stored in memory by employing proper generalized decompositions. Although the presented method can be broadly applied, it is particularly well suited in manufacturing processes involving localized physics that depend on many parameters, such as welding. After introducing the vademecum‐generalized finite element method formulation, we present some numerical examples related to the simulation of thermal models encountered in welding processes. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
77.
78.
Josiele S. Teixeira Diego C. Knupp Antônio J. Silva Neto 《Inverse Problems in Science & Engineering》2017,25(6):909-935
The present work addresses the problem of structural damage identification built on the statistical inversion approach. Here, the damage state of the structure is continuously described by a cohesion parameter, which is spatially discretized by the finite element method. The inverse problem of damage identification is then posed as the determination of the posterior probability densities of the nodal cohesion parameters. The Markov Chain Monte Carlo method, implemented with the Metropolis–Hastings algorithm, is considered in order to approximate the posterior probabilities by drawing samples from the desired joint posterior probability density function. With this approach, prior information on the sought parameters can be used and the uncertainty concerning the known values of the material properties can be quantified in the estimation of the cohesion parameters. The assessment of the proposed approach has been performed by means of numerical simulations on a simply supported Euler–Bernoulli beam. The damage identification and assessment are performed considering time domain response data. Different damage scenarios and noise levels were addressed, demonstrating the feasibility of the proposed approach. 相似文献
79.
E Ierardi A Amoruso T La Notte R Francavilla S Castellaneta E Marrazza RA Monno A Francavilla 《Canadian Metallurgical Quarterly》1998,43(12):2733-2737
With the aim of investigating a possible relationship between "objective" halitosis (established by sulfide levels in the breath) and Helicobacter pylori, we performed a study in 58 dyspeptic patients reported to suffer from "bad breath." Furthermore, we evaluated the effects on halitosis of eradication therapy (only for H. pylori-positive patients) and chlorhexidine antiseptic mouth rinses (in all patients). Sulfide compound assay indicated objective halitosis in 52/58 patients, 30 of whom were positive and 22 negative for H. pylori. In 19/30 eradication by double therapy provoked a decrease to below the cutoff value of sulfide levels in 15. In the other 11 of the 30 subjects, in whom H. pylori positivity persisted, halitosis parameters did not change. Chlorexidine reduced sulfides to below the cutoff value in 16/22 H. pylori-negative patients, but did not provoke any change in the 11 unsuccessfully treated H. pylori-positive subjects. In these, objective halitosis disappeared only after a successful eradication by triple therapy (9/11). Our results show a possible association between halitosis and H. pylori since bacterial eradication may resolve the symptom. Antiseptic mouthwashes may be effective only in absence of H. pylori, when halitosis may be due to oral putrefactive microbial activity. In a small number of subjects the cause and treatment of halitosis need to be clarified. 相似文献
80.
Aitor Almeida Pablo Orduña Eduardo Castillejo Diego López-de-Ipiña Marcos Sacristán 《Personal and Ubiquitous Computing》2011,15(4):419-429
As the dependence on mobile devices increases, the need for supporting a wider range of users and devices becomes crucial.
Elders and people with disabilities adopt new technologies reluctantly, a tendency caused by the lack of adaptation of these
technologies to their needs. To address this challenge, this paper describes a framework, Imhotep, whose aim is to aid developers
in the accessible application creation process, making the creation of user-centered applications easier and faster. Our framework
allows to easily adapt the applications to the constraints imposed by the user capabilities (sensorial, cognitive, and physical
capabilities) and device capabilities by providing a repository that will manage the compilation and deployment of applications
that include a set of preprocessor directives in the source code. These directives are enhanced with concepts that are automatically
adjusted to the current trends of mobile devices by using a Fuzzy Knowledge-Eliciting Reasoner. Our final goal is to increase
the number of applications targeted to elders and people with disabilities providing tools that facilitate their development.
The paper also describes the evaluation of both the accuracy of the fuzzy terms generated for mobile devices and the usability
of the proposed platform. 相似文献