全文获取类型
收费全文 | 7564篇 |
免费 | 921篇 |
国内免费 | 642篇 |
专业分类
电工技术 | 1078篇 |
综合类 | 562篇 |
化学工业 | 552篇 |
金属工艺 | 123篇 |
机械仪表 | 603篇 |
建筑科学 | 448篇 |
矿业工程 | 85篇 |
能源动力 | 208篇 |
轻工业 | 630篇 |
水利工程 | 224篇 |
石油天然气 | 138篇 |
武器工业 | 80篇 |
无线电 | 358篇 |
一般工业技术 | 1571篇 |
冶金工业 | 288篇 |
原子能技术 | 170篇 |
自动化技术 | 2009篇 |
出版年
2024年 | 39篇 |
2023年 | 146篇 |
2022年 | 261篇 |
2021年 | 304篇 |
2020年 | 446篇 |
2019年 | 384篇 |
2018年 | 348篇 |
2017年 | 410篇 |
2016年 | 423篇 |
2015年 | 390篇 |
2014年 | 508篇 |
2013年 | 734篇 |
2012年 | 520篇 |
2011年 | 565篇 |
2010年 | 374篇 |
2009年 | 406篇 |
2008年 | 369篇 |
2007年 | 435篇 |
2006年 | 373篇 |
2005年 | 316篇 |
2004年 | 268篇 |
2003年 | 208篇 |
2002年 | 164篇 |
2001年 | 126篇 |
2000年 | 130篇 |
1999年 | 78篇 |
1998年 | 77篇 |
1997年 | 62篇 |
1996年 | 66篇 |
1995年 | 36篇 |
1994年 | 32篇 |
1993年 | 27篇 |
1992年 | 19篇 |
1991年 | 19篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1983年 | 3篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1976年 | 1篇 |
1966年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1960年 | 1篇 |
1959年 | 5篇 |
1957年 | 1篇 |
排序方式: 共有9127条查询结果,搜索用时 14 毫秒
31.
采用传递比较法对二厘米微波衰减标准装置不确定度进行了验证。测量标准装置的重复性以组内实验标准偏差sn(A)定量表征,测量标准装置的稳定性用组间实验标准偏差sm定量表征。 相似文献
32.
This article argues that it is not uncommon for people forming justice judgments to lack information that is most relevant in the particular situation. In information-uncertain conditions, people may therefore construct justice judgments by relying on how they feel about the events they have encountered, and justice judgments may hence be strongly influenced by affect information. Findings show that in information-uncertain conditions, the affective states that people had been in prior and unrelated to the justice event indeed strongly influenced their justice judgments. These findings thus reveal that in situations of information uncertainty, people's judgments of justice can be very subjective, susceptible to affective states that have no logical relationship with the justice judgments they are constructing. Implications for the social psychology of justice and the literature on social cognition and affect are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
33.
An Interval Fuzzy Multiobjective Watershed Management Model for the Lake Qionghai Watershed, China 总被引:4,自引:0,他引:4
Lijing Wang Wei Meng Huaicheng Guo Zhenxing Zhang Yong Liu Yingying Fan 《Water Resources Management》2006,20(5):701-721
Integrated watershed management is required to ensure the reasonable use of resources and reconcile interactions among natural and human systems. In the present study, an interval fuzzy multiobjective programming (IFMOP) method was used to solve an integrated watershed management problem. Based on system analysis, an IFMOP model suitable for a lake watershed system {IFMOPLWS} was developed and applied to the Lake Qionghai watershed in China. Scenario analysis and an interactive approach were used in the solution process. In this manner, various system components were incorporated into one framework for holistic consideration and optimization. Integrality and uncertainty, as well as the multiobjective and dynamic characteristics of the watershed system, were well addressed. Using two scenarios, two planning schemes were generated. Agriculture, tourism, macroeconomics, cropland use, water supply, forest coverage, soil erosion, and water pollution were fully interpreted and compared to identify a preferable planning alternative for local agencies. This study showed that the IFMOPLWS is a powerful tool for integrated watershed management planning and can provide a solid base for sustainable watershed management. 相似文献
34.
钱先友 《苏州科技学院学报(工程技术版)》2002,15(1):87-89
文章介绍了不确定度的定义及其一般计算公式,通过具体实例介绍了实验后不确定度的计算和实验前的误差估计。并对有多种可能的实验方案,利用误差估计的方法,选择出最佳的实验方案,使其不确定度最小。 相似文献
35.
Sources and current methods of analysis of uncertainty from randomness, fuzziness and ignorance or incomplete knowledge in seismic hazard assessment problem are briefly discussed at beginning; understandings of the authors are then presented in the following order. All three types of uncertainty come from incomplete knowledge. Probabilistic method can be applied to all of them, objective probability for random factors and subjective probability for the other two types of uncertain factors. Discrete subjective probability mass functions for incomplete and fuzzy factors can be obtained from logic-tree and membership functions respectively. Fractile curves may be used to show the scattering of any uncertainty factor, but a unified probabilistic treatment may be applied to any combination of all three types of uncertainty. 相似文献
36.
蔡绯 《中国计量学院学报》1996,(1)
本文根据压力传感器(静态)国家计量检定规程,对压力传感器静态检定装置进行误差分析,得出该装置的测量不确定度。最后,通过实例说明实际测量不确定度与理论分析相符合。 相似文献
37.
中国加入WTO后,与外界的交流频繁了,用测量不确定度描述各种报告的测试结果,越来越迫切。钢材的外型尺寸检验、化学成分元素含量分析、钢材的力学性能测试等等的检验报告,都需要应用不确定度的理论。本文主要介绍了在这些测量中的不确定度问题。 相似文献
38.
Marcela Brugnach Andrew Tagg Florian Keil Wim J. de Lange 《Water Resources Management》2007,21(7):1075-1090
The use of computer models offers a general and flexible framework that can help to deal with some of the complexities and
difficulties associated with the development of water management plans as prescribed by the Water Framework Directive. However,
despite the advantages modelling presents, the integration of information derived from models into policy is far away from
being trivial or the norm. Part of the difficulties of this integration is rooted in the lack of confidence policy makers
have on the incorporation of modelling information into policy formulation. In this paper we examine the reasons for this
apparent lack of confidence and explore how some tools, presently in use, address this problem. We conclude that public confidence
in models is highly dependent on the way uncertainties are addressed and suggest possible directions of action to improve
the current situation. Four real case studies illustrate how computer models have been used in The Netherlands for carrying
out management plans at regional and national scale. We suggest that the solution to integrate modelling information into
policy formulation lies on both the modelling and the policy-making communities. 相似文献
39.
40.
Fusion of multi-sensor information is an important technology, which is growing exponentially due to its tremendous application potential in many areas. Effective fusion of data from sensors is very critical in increasing an intelligent system's capability to accomplish complex tasks. Appropriate fusion technologies are needed to be developed specially when a system requires redundant sensors to be used. More the redundancy in sensors, more is the computational complexity for controlling the system and more is its intelligence level. This research presents a strategy developed for multiple sensor fusion, based on geometric optimization. Each sensor's uncertainty has been modeled using classical Lagrangian optimization techniques. However, the uniqueness and effectiveness of the present technique lies on the fact that starting from the optimized value as initial estimate the accuracy of the sensory information has further been improved up to any pre defined bounded range, by developing two architectures – FFA (fission–fusion architecture) and FDD (fusion in differential domain). Sufficient evidences and analyses have been provided in the paper to show its effectiveness in various applications. 相似文献