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41.
This paper describes the development of multi-item scales for measuring user perceptions of the ease-of-use and usefulness of the Web (hereafter web), incorporating a system task focus into the scales dimensional structure (e.g. how easy or useful the web is for information search, communication and or purchasing). The items are tested on 2077 web users recruited using a web survey, revealing four factors for each scale. Perceived ease-of-web use consists of learning, search and find, transaction and communication ease, and perceived web usefulness consists of communication, purchase, information search and acquisition, and access to quality products and information. A regression analysis on web usage frequency shows how easy users find it to learn how to use the web and how useful the web is for purchasing are the best predictors of how frequently they will use the web. These results highlight the importance of training users how to effectively use hypermedia-based systems like the web, and the design of systems that are easy to navigate and that provide advanced functionality for transactional activity.  相似文献   
42.
基于美国约瑟夫.奈教授提出的"软实力"(soft power)的理论,分析了我国高校开展对外交流在提升国家文化软实力的作用和尚待发挥的潜在优势,并结合福州大学等高校的案例分析了文化软实力视野下的高校对外交流的发展路径,力图从更高的角度来提升高校对外交流的实效。  相似文献   
43.
戴秋萍 《中国水利》2012,(20):47-49
结合世行贷款江苏省淮河流域重点平原洼地治理项目泰东河工程招标投标工作,对比分析世行贷款项目国内竞争性招标与国内项目公开招标两种方式,从招标过程中的各环节差异提出应重点关注的问题,为做好类似项目招标投标提供一定借鉴.  相似文献   
44.
This article presents the results of a time-limited psychological relief effort using eye movement desensitization and reprocessing (EMDR) following the attacks on the World Trade Center on September 11, 2001. Clients made highly significant positive gains on a range of outcome variables, including validated psychometrics and self-report scales. Analyses of the data suggest 2 broad conclusions: EMDR is a useful treatment intervention both in the immediate aftermath of disaster as well as later; the longer treatment is delayed, the greater the level of disturbance experienced by clients. Also discussed are problems in conducting research during mass disaster response situations. A demonstration of an analog to a wait-list control group is provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
45.
Hydrographic data collected in the upper 50 m off La Jolla, CA, USA (31°N, 117°W) between 1970 and 1972 were reanalyzed to examine temporal variability in the local temperature-nitrate relationship and to document how chlorophyll a concentration and phytoplankton community structure covary with the temperature-nitrate relationship. Based on the linear expression y=mx+b, the y-intercepts (b), slopes (m), and x-intercepts (−b/m or nitrate depletion temperature, NDT) of four seasonal (January-March, April-June, July-September, and October-December) temperature-nitrate relationships, obtained from the combined multiyear data set, were statistically different from each other and varied around overall multiyear values of b=72.73 μM, m=−5.33 μM °C−1, and NDT=13.65 °C. Three interannual temperature-nitrate relationships from February to April 1970, 1971, and 1972 also had y-intercepts, slopes, and x-intercepts that were statistically different from each other. Nevertheless, limited variability in direct comparisons among seasonal or interannual regression lines and a 1 °C La Jolla NDT range compared to a 25 °C global NDT range supported the general utility of NDT-based comparisons. A nitrate-normalized temperature axis (T−NDT) was created for the La Jolla data set by subtracting NDT from the recorded water column temperatures (T). Chlorophyll a reached a maximum between 0 and 2 °C on this T-NDT axis that ranged from −4 to 10 °C. Microscope-based determinations of La Jolla centric diatom, pennate diatom and dinoflagellate abundances, and La Jolla chlorophyll a, partitioned in proportion to the numerical abundance of the three groups, both peaked in logical progression along the T-NDT axis. In a separate analysis of high-performance liquid chromatography (HPLC) data from three Atlantic Meridional Transect (AMT) cruises (50°N to 52°S), chlorophyll a peaked below 0 °C and three different phytoplankton classes, nanoflagellates, large eukaryotes and prokaryotes, distributed in logical progression along a sea surface temperature (SST) minus NDT axis. To further generalize these results, a previously reported 1° latitude×1° longitude grid of NDTs for the world ocean was applied to satellite-derived grids of SST for March 1999 through June 2000. The SST−NDT calculation provided a standard nitrate-normalized axis simultaneously applicable to all locations in the world ocean. Sixteen plots of satellite-derived chlorophyll a versus SST−NDT for March 1999 through June 2000 demonstrated the opposing seasonal movements of northern and southern hemisphere chlorophyll a along the SST-NDT axis. Based on the phytoplankton community patterns along the temperature minus NDT in the La Jolla and AMT data sets, this chlorophyll a movement along the SST-NDT axis can be associated with phytoplankton community changes related to location around SST−NDT=0 °C. The SST−NDT index appears to provide a useful tool for interpreting the character of the phytoplankton community structure contributing to satellite-derived chlorophyll a in the world ocean.  相似文献   
46.
The growing popularity of the information superhighway has opened up exciting opportunities for companies looking to, not only maintain their current customer base, but also to reach new customers. One of the most popular methods to enter into cybermarketing has been to establish a home page or Web site on the Internet. Almost two-thirds of Fortune 500 companies currently maintain home pages on the Web. An analysis of the content of corporate home pages provides useful insights. Over four-fifths of the companies display products and services (93.2%) and company overview (86.1%) information. Roughly three-fourths of the companies present interactive feedback (79.3%) and what's new (71.1%). Less than one-third (26.2%) of Fortune 500 companies provide for online business. An analysis of the data also provides valuable insight into the future trends of home page usage by large business organizations.  相似文献   
47.
介绍了狭义相对论时空的一种新图示法,并用此图示法解释了诸如长度收缩、时间延缓等相对论效应;本方法具有简洁、直观的特点。  相似文献   
48.
With the explosive growth of information in the WWW, it is becoming increasingly difficult for the user to find information of interest. Visualisations may be helpful in assisting the users in their information retrieval task. Effective visualisation of the structure of a WWW site is extremely useful for browsing through the site. Visualisation can also be used to augment a WWW search engine when too many or too few results are retrieved. In this paper, we discuss several visualisations we have developed to facilitate information retrieval on the WWW. With VRML becoming the standard for graphics on the Web and efficient VRML browsers becoming available, VRML was used for developing these visualisations. Unique visualisations like focus + context views of WWW nodes and semantic visualisation are presented and examples are given on scenarios where the visualisations are useful.  相似文献   
49.
给出了一个完整的基于Java技术的WebGIS框架 ,论述了其系统功能和开发技术 ,并指出了其优点  相似文献   
50.
Although it has become very common to use World Wide Web‐based information in many educational settings, there has been little research on how to better search and organize Web‐based information. This paper discusses the shortcomings of Web search engines and Web browsers as learning environments and describes an alternative Web search environment that combines a concept mapping and a data mining technique to address their drawbacks.  相似文献   
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