全文获取类型
收费全文 | 5180篇 |
免费 | 363篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 34篇 |
综合类 | 1篇 |
化学工业 | 914篇 |
金属工艺 | 85篇 |
机械仪表 | 86篇 |
建筑科学 | 154篇 |
矿业工程 | 7篇 |
能源动力 | 85篇 |
轻工业 | 949篇 |
水利工程 | 62篇 |
石油天然气 | 15篇 |
无线电 | 224篇 |
一般工业技术 | 793篇 |
冶金工业 | 1403篇 |
原子能技术 | 14篇 |
自动化技术 | 721篇 |
出版年
2024年 | 6篇 |
2023年 | 36篇 |
2022年 | 32篇 |
2021年 | 93篇 |
2020年 | 92篇 |
2019年 | 110篇 |
2018年 | 182篇 |
2017年 | 186篇 |
2016年 | 208篇 |
2015年 | 170篇 |
2014年 | 218篇 |
2013年 | 422篇 |
2012年 | 324篇 |
2011年 | 318篇 |
2010年 | 231篇 |
2009年 | 234篇 |
2008年 | 230篇 |
2007年 | 226篇 |
2006年 | 119篇 |
2005年 | 99篇 |
2004年 | 114篇 |
2003年 | 96篇 |
2002年 | 106篇 |
2001年 | 79篇 |
2000年 | 64篇 |
1999年 | 81篇 |
1998年 | 539篇 |
1997年 | 294篇 |
1996年 | 191篇 |
1995年 | 96篇 |
1994年 | 78篇 |
1993年 | 75篇 |
1992年 | 15篇 |
1991年 | 11篇 |
1990年 | 12篇 |
1989年 | 11篇 |
1988年 | 22篇 |
1987年 | 12篇 |
1986年 | 13篇 |
1985年 | 19篇 |
1984年 | 7篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 19篇 |
1976年 | 28篇 |
1970年 | 1篇 |
排序方式: 共有5547条查询结果,搜索用时 9 毫秒
121.
Rubén Fuentes-Fernández Iván García-Magariño Alma María Gómez-Rodríguez Juan Carlos González-Moreno 《Engineering Applications of Artificial Intelligence》2010,23(3):432-444
The formalization of engineering processes is necessary for guaranteeing the quality and cost of the products involved. Agent-oriented engineering has already proposed development processes that still need to be further formalized to be applicable by non-researchers. This paper proposes a technique to instantiate processes for specific agent-oriented methodologies. This technique is based on three orthogonal views that are respectively related with lifecycles, disciplines and guidances. In addition, processes are modeled with a tool, which is automatically generated from a process metamodel inspired by the software & systems process engineering metamodel. Accordingly, engineers can choose the methodology–process pair best-suited for the characteristics of their project. The paper illustrates the approach based on the unified development process and the scrum process for the INGENIAS methodology and compares the results with other existing alternatives. 相似文献
122.
A. L. Herrera-May L. A. Aguilera-Cortés P. J. García-Ramírez H. Plascencia-Mora M. Torres-Cisneros 《Microsystem Technologies》2010,16(12):2067-2074
Nano-electro-mechanical systems (NEMS) resonators integrated by a double clamped beam with variable cross-section are used
in several applications such as chemical and biological detectors, high-frequency filters, and signal processing. The structure
of these resonators can experience intrinsic stresses produced during their fabrication process. We present an analytical
model to estimate the first bending resonant frequency of NEMS resonators based on a double clamped beam with three cross-sections,
which considers the intrinsic stress effect on the resonant structure. This model is obtained using the Rayleigh and Macaulay
methods, as well as the Euler–Bernoulli beam theory. We applied the analytical model to a silicon carbide (SiC) resonator
of 186 nm thickness reported in the literature. This resonator has a total length ranking from 80 to 258 μm and is subjected
to a tensile intrinsic stress close to 110 MPa. Results from this model show good agreement with experimental results. The
analytic frequencies have a maximum relative difference less than 6.3% respect to the measured frequencies. The tensile intrinsic
stress on the resonant structure causes a significantly increase on its bending resonant frequency. The proposed model provides
an insight into the study of the intrinsic stress influence on the resonant frequency of this nanostructure. In addition,
this model can estimate the frequency shift due to the variations of the resonator geometrical parameters. 相似文献
123.
Alfonso Rodríguez Ignacio García-Rodríguez de Guzmán Eduardo Fernández-Medina Mario Piattini 《Information and Software Technology》2010,52(9):945-971
ContextModel-Driven Development (MDD) is an alternative approach for information systems development. The basic underlying concept of this approach is the definition of abstract models that can be transformed to obtain models near implementation. One fairly widespread proposal in this sphere is that of Model Driven Architecture (MDA). Business process models are abstract models which additionally contain key information about the tasks that are being carried out to achieve the company’s goals, and two notations currently exist for modelling business processes: the Unified Modelling Language (UML), through activity diagrams, and the Business Process Modelling Notation (BPMN).ObjectiveOur research is particularly focused on security requirements, in such a way that security is modelled along with the other aspects that are included in a business process. To this end, in earlier works we have defined a metamodel called secure business process (SBP), which may assist in the process of developing software as a source of highly valuable requirements (including very abstract security requirements), which are transformed into models with a lower abstraction level, such as analysis class diagrams and use case diagrams through the approach presented in this paper.MethodWe have defined all the transformation rules necessary to obtain analysis class diagrams and use case diagrams from SBP, and refined them through the characteristic iterative process of the action-research method.ResultsWe have obtained a set of rules and a checklist that make it possible to automatically obtain a set of UML analysis classes and use cases, starting from SBP models. Our approach has additionally been applied in a real environment in the area of the payment of electrical energy consumption.ConclusionsThe application of our proposal shows that our semi-automatic process can be used to obtain a set of useful artifacts for software development processes. 相似文献
124.
Francisco J. Pino César Pardo Félix García Mario Piattini 《Information and Software Technology》2010,52(10):1044-1061
ContextDiagnosing processes in a small company requires process assessment practices which give qualitative and quantitative results; these should offer an overall view of the process capability. The purpose is to obtain relevant information about the running of processes, for use in their control and improvement. However, small organizations have some problems in running process assessment, due to their specific characteristics and limitations.ObjectiveThis paper presents a methodology for assessing software processes which assist the activity of software process diagnosis in small organizations. There is an attempt to address issues such as the fact that: (i) process assessment is expensive and typically requires major company resources and (ii) many light assessment methods do not provide information that is detailed enough for diagnosing and improving processes.MethodTo achieve all this, the METvalCOMPETISOFT assessment methodology was developed. This methodology: (i) incorporates the strategy of internal assessments known as rapid assessment, meaning that these assessments do not take up too much time or use an excessive quantity of resources, nor are they too rigorous and (ii) meets all the requirements described in the literature for an assessment proposal which is customized to the typical features of small companies.ResultsThis paper also describes the experience of the application of this methodology in eight small software organizations that took part in the COMPETISOFT project. The results obtained show that this approach allows us to obtain reliable information about the strengths and weaknesses of software processes, along with information to companies on opportunities for improvement.ConclusionThe assessment methodology proposed sets out the elements needed to assist with diagnosing the process in small organizations step-by-step while seeking to make its application economically feasible in terms of resources and time. From the initial application it may be seen that this assessment methodology can be useful, practical and suitable for diagnosing processes in this type of organizations. 相似文献
125.
Iván García-Magariño Rubén Fuentes-Fernández Jorge J. Gómez-Sanz 《Information and Software Technology》2010,52(4):422-435
Computer-Aided Software Engineering (CASE) tools support modeling-related activities in development projects. Given the variety of tools and functionalities, it is quite common to work with several tools in the same project. However, data cannot usually be exchanged between these tools without loss of information. Recent approaches address this model interchange problem using metamodels to characterize the involved information and transformations to export/import it. Nevertheless, most of these solutions focus on the abstract syntax of models. They fail to consider aspects such as the presentation of models or tool-specific information, which are either disregarded or represented in ad-hoc ways that make difficult their processing. In order to overcome these limitations, this paper introduces a framework to define metamodels of CASE tools and a process to carry out the model interchange using them. The proposed metamodels have a modular organization with several internal metamodels. Each of them is aimed at describing some specific information about content, structure and presentation for both models and tools. The paper illustrates this approach with a case study used for comparison with existing works for this problem. 相似文献
126.
Although directory-based cache-coherence protocols are the best choice when designing chip multiprocessors with tens of cores on-chip, the memory overhead introduced by the directory structure may not scale gracefully with the number of cores. Many approaches aimed at improving the scalability of directories have been proposed. However, they do not bring perfect scalability and usually reduce the directory memory overhead by compressing coherence information, which in turn results in extra unnecessary coherence messages and, therefore, wasted energy and some performance degradation. In this work, we present a distributed directory organization based on duplicate tags for tiled CMP architectures whose size is independent on the number of tiles of the system up to a certain number of tiles. We demonstrate that this number of tiles corresponds to the number of sets in the private caches. Additionally, we show that the area overhead of the proposed directory structure is 0.56% with respect to the on-chip data caches. Moreover, the proposed directory structure keeps the same information than a non-scalable full-map directory. Finally, we propose a mechanism that takes advantage of this directory organization to remove the network traffic caused by replacements. This mechanism reduces total traffic by 15% for a 16-core configuration compared to a traditional directory-based protocol. 相似文献
127.
Rocío de Andrés José Luis García-Lapresta Luis Martínez 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2010,14(1):21-34
The performance appraisal is a relevant process to keep and improve the competitiveness of companies in nowadays. In spite
of this relevance, the current performance appraisal models are not sufficiently well-defined either designed for the evaluation
framework in which they are defined. This paper proposes a performance appraisal model where the assessments are modelled
by means of linguistic information provided by different sets of reviewers in order to manage the uncertainty and subjectivity
of such assessments. Therefore, the reviewers could express their assessments in different linguistic scales according to
their knowledge about the evaluated employees, defining a multi-granular linguistic evaluation framework. Additionally, the
proposed model will manage the multi-granular linguistic labels provided by appraisers in order to compute collective assessments
about the employees that will be used by the management team to make the final decision about them. 相似文献
128.
129.
Marcello La Rosa Hajo A. Reijers Wil M.P. van der Aalst Remco M. Dijkman Jan Mendling Marlon Dumas Luciano García-Bañuelos 《Expert systems with applications》2011,38(6):7029-7040
Business process models are becoming available in large numbers due to their widespread use in many industrial applications such as enterprise and quality engineering projects. On the one hand, this raises a challenge as to their proper management: how can it be ensured that the proper process model is always available to the interested stakeholder? On the other hand, the richness of a large set of process models also offers opportunities, for example with respect to the re-use of existing model parts for new models. This paper describes the functionality and architecture of an advanced process model repository, named APROMORE. This tool brings together a rich set of features for the analysis, management and usage of large sets of process models, drawing from state-of-the art research in the field of process modeling. A prototype of the platform is presented in this paper, demonstrating its feasibility, as well as an outlook on the further development of APROMORE. 相似文献
130.
Model-driven Engineering (MDE) has attained great importance in both the Software Engineering industry and the research community,
where it is now widely used to provide a suitable approach with which to improve productivity when developing software artefacts.
In this scenario, measurement models (software artefacts) have become a fundamental point in improvement of productivity,
where MDE and Software Measurement can reap mutual benefits. MDE principles and techniques can be used in software measurement
to build more automatic and generic solutions, and to achieve this, it is fundamental to be able to develop software measurement
models. To facilitate this task, a domain-specific language named “Software Measurement Modelling Language” (SMML) has been
developed. This paper tackles the question of whether the use of SMML can assist in the definition of software measurement
models. An empirical study was conducted, with the aim of verifying whether SMML makes it easier to construct measurement
models which are more usable and maintainable as regards textual notation. The results show that models which do not use the
language are more difficult—in terms of effort, correctness and efficiency—to understand and modify than those represented
with SMML. Additional feedback was also obtained, to verify the suitability of the graphical representation of each symbol
(element or relationship) of SMML. 相似文献