首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2053篇
  免费   116篇
  国内免费   2篇
电工技术   44篇
化学工业   498篇
金属工艺   47篇
机械仪表   33篇
建筑科学   44篇
矿业工程   1篇
能源动力   50篇
轻工业   200篇
水利工程   23篇
石油天然气   17篇
无线电   263篇
一般工业技术   301篇
冶金工业   422篇
原子能技术   21篇
自动化技术   207篇
  2023年   11篇
  2022年   35篇
  2021年   41篇
  2020年   36篇
  2019年   36篇
  2018年   37篇
  2017年   59篇
  2016年   70篇
  2015年   55篇
  2014年   74篇
  2013年   89篇
  2012年   68篇
  2011年   105篇
  2010年   80篇
  2009年   84篇
  2008年   81篇
  2007年   87篇
  2006年   73篇
  2005年   61篇
  2004年   57篇
  2003年   55篇
  2002年   68篇
  2001年   40篇
  2000年   31篇
  1999年   37篇
  1998年   143篇
  1997年   76篇
  1996年   66篇
  1995年   61篇
  1994年   40篇
  1993年   42篇
  1992年   22篇
  1991年   23篇
  1990年   22篇
  1989年   19篇
  1988年   16篇
  1987年   21篇
  1986年   22篇
  1985年   16篇
  1984年   15篇
  1983年   12篇
  1982年   6篇
  1981年   11篇
  1980年   6篇
  1979年   8篇
  1977年   5篇
  1976年   17篇
  1975年   4篇
  1970年   6篇
  1968年   4篇
排序方式: 共有2171条查询结果,搜索用时 15 毫秒
51.
For domains in which fitness is subjective or difficult to express formally, interactive evolutionary computation (IEC) is a natural choice. It is possible that a collaborative process combining feedback from multiple users can improve the quality and quantity of generated artifacts. Picbreeder, a large-scale online experiment in collaborative interactive evolution (CIE), explores this potential. Picbreeder is an online community in which users can evolve and share images, and most importantly, continue evolving others' images. Through this process of branching from other images, and through continually increasing image complexity made possible by the underlying neuroevolution of augmenting topologies (NEAT) algorithm, evolved images proliferate unlike in any other current IEC system. This paper discusses not only the strengths of the Picbreeder approach, but its challenges and shortcomings as well, in the hope that lessons learned will inform the design of future CIE systems.  相似文献   
52.
The introduction of Internet and Information and communication Technologies (ICT) in offices is a global phenomenon that transformed white-collar worker job demands. Although there are several studies of e-skills and mental workload for central countries, there is a lack of similar studies for the Latin American context. An online snowball sampled (n = 352) survey was developed and validated by the authors (internal consistency = 0.7). We characterized ICT worker profiles from e-skills and these dimensions: attitudes toward, resources usage and technology dependency. Mental Strain was assessed with raw task load index (RTLX) and correlated with the proposed profiles by means of paired T-tests and Mann–Whitney Tests. The sample was characterized by 7.2% of non visual display terminal users and 92.8% of visual display terminal, ICT skilled users. Of the latter, 30.7% were ICT practitioners, 30.4% were ICT Users and 27.2% were E-Business Users. Non VDT users’ mental strain was statistically meaningful smaller than VDT–ICT skilled users’ mental workload. No statistical differences were found in RTLX results when comparing ICT skilled user profiles. Non VDT users can be identified from ICT skilled Users by their lower ITC Dependency and minor use of ICT resources. There were no differences in those dimensions among ICT skilled Profiles. Attitude toward these technologies was a distinct factor for ICT Users in relation to ICT Practitioners and ITC Business Users. The application of this tool in peripheral and central countries would allow a complete ergonomical characterization of white-collar workers within the Information Society.  相似文献   
53.
54.
Recently, much attention has been given to performance management within collaborative environments resulting in a wide variety of performance measurement/management frameworks. However, practically all of these frameworks present a common gap regarding the information treatment needs that support these frameworks. This issue is even more important in the case of Small and Medium-sized Enterprises (SMEs) due to their special characteristics. For that purpose, this paper presents an approach called Global Performance Management (GPM) Framework composed of a methodology, an information architecture and a technological solution, focusing mainly on the information architecture. The methodology guides SMEs when defining, developing, deploying and operating the GPM framework. The information architecture consists of a set of elements that support the tasks of collection, treatment and analysis of the used information, which complement the methodology to build a real model for the GPM framework. Finally, the technological solution bridges the engineering and conceptual environment, with the real-world operational and executable environment, following the path defined by the methodology. The information architecture was applied to two European pilots, achieving satisfactory results, which are highlighted in the paper as well as the main barriers encountered and solutions provided.  相似文献   
55.
This work investigates the problem of combining deficient evidence for the purpose of quality assessment. The main focus of the work is modeling vagueness, ambiguity, and local nonspecificity in information within a unified approach. We introduce an extended fuzzy Dempster–Shafer scheme based on the simultaneous use of fuzzy interval‐grade and interval‐valued belief degree (IGIB). The latter facilitates modeling of uncertainties in terms of local ignorance associated with expert knowledge, whereas the former allows for handling the lack of information on belief degree assignments. Also, generalized fuzzy sets can be readily transformed into the proposed fuzzy IGIB structure. The reasoning for quality assessment is performed by solving nonlinear optimization problems on fuzzy Dempster–Shafer paradigm for the fuzzy IGIB structure. The application of the proposed inference method is investigated by designing a reasoning scheme for water quality monitoring and validated through the experimental data available for different sampling points in a water distribution network. © 2011 Wiley Periodicals, Inc.  相似文献   
56.
Schaeffer's sign language consists of a reduced set of gestures designed to help children with autism or cognitive learning disabilities to develop adequate communication skills. Our automatic recognition system for Schaeffer's gesture language uses the information provided by an RGB‐D camera to capture body motion and recognize gestures using dynamic time warping combined with k‐nearest neighbors methods. The learning process is reinforced by the interaction with the proposed system that accelerates learning itself thus helping both children and educators. To demonstrate the validity of the system, a set of qualitative experiments with children were carried out. As a result, a system which is able to recognize a subset of 11 gestures of Schaeffer's sign language online was achieved.  相似文献   
57.
Starting from the scattering data, the initial-value problem for the focusing nonlinear Schrödinger equation is solved numerically by following the path of the inverse scattering transform. The numerical results of an extensive experimentation suggest that: (a) our method is very effective, whenever the scattering data are analytically known; (b) the split-step Fourier method is not really effective if the exact solution is not smooth enough.  相似文献   
58.
The paper focuses on collaborative STEP-based CAD/CAM/CNC supply chains to program and automate machining process data monitoring and traceability activities. A traceability interface (traceability nc_functions) is defined for the new CNC programming standard ISO STEP-NC. CAM systems will be able to program monitoring and data access activities by inserting traceability nc_function calls in CNC programs. On the shop floor, controllers will automatically interpret these nc_functions to access process data while machining and will relate data records with the corresponding machining operations in a STEP-NC part program. With both types of information—process data and standard machining program (STEP-NC part program)—spread and technologically heterogeneous engineering systems will have full knowledge about what has happened in production. Traceability data access automation will assure data reliability. The paper describes a traceability scenario where standards such as MTConnect and ISA-95 support, rather than interfere with, the STEP-NC traceability proposal.  相似文献   
59.
A brief history of robotic systems in knee arthroplasty is provided. The place of autonomous robots is then discussed and compared to more recent 'hands-on' robotic systems that can be more cost effective. The case is made for robotic systems to have a clear justification, with improved benefits compared to those from cheaper navigation systems. A number of more recent, smaller, robot systems for knee arthroplasty are also described. A specific example is given of an active constraint medical robot, the ACROBOT system, used in a prospective randomized controlled trial of unicondylar robotic knee arthroplasty in which the robot was compared to conventional surgery. The results of the trial are presented together with a discussion of the need for measures of accuracy to be introduced so that the efficacy of the robotic surgery can be immediately identified, rather than have to wait for a number of years before long-term clinical improvements can be demonstrated.  相似文献   
60.
For the last 6 years we have been using Miconazole cream in the treatment of tinea and vaginal candidiasis. We think that it is at least as good as the best drugs for this purpose, but consider it difficult to decide about its superiority. Therefore we refrain from describing this part of our experience in detail. We have employed Miconazole "per os" at the daily doses of 24-28 mg./kg. in treating 3 cases of tinea corporis or cruris by "Trichophyton rubrum". Symptoms ceased in 3 days; mycologic examination turned negative in 2 weeks; treatment ended in apparent cure in 3 weeks. We have employed Miconazole "per venam" and "per os" in the treatment of: mycetomata (2) by "Streptomyces somaliensis", without success; mycetoma by "Madurella grisea" (1), without success; chromomycosis by a 5-flucytosine resistant strain of "Cladosporium carrionii" (1), without success; paracoccidioidosis (5) with lesions in mouth and lungs, with good results; leishmaniasis by "Leishmania brasiliensis" (1), without success; mucocutaneous disseminated candidiasis (1), with very good results. Tolerance has been excellent: but pruritus appeared from the third week with 600 or more mg. "per venam", in several patients. Doses varied between 10 and 50 mg./kg./day. One patient, who suffered with candidiasis, is taking 50 to 30 mg./kg./day since more than a year ago and, being a child, he is feeling well and growing to be normal. We recommend employing Miconazole against systemic canidiasis, sulpharesistant paracoccidioidosis and assaying it further in tinea (at least, in griseofulvin-resistant cases).  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号