全文获取类型
收费全文 | 918篇 |
免费 | 225篇 |
国内免费 | 21篇 |
专业分类
电工技术 | 54篇 |
综合类 | 60篇 |
化学工业 | 173篇 |
金属工艺 | 43篇 |
机械仪表 | 75篇 |
建筑科学 | 55篇 |
矿业工程 | 18篇 |
能源动力 | 72篇 |
轻工业 | 66篇 |
水利工程 | 5篇 |
石油天然气 | 93篇 |
武器工业 | 7篇 |
无线电 | 102篇 |
一般工业技术 | 130篇 |
冶金工业 | 36篇 |
原子能技术 | 18篇 |
自动化技术 | 157篇 |
出版年
2024年 | 19篇 |
2023年 | 83篇 |
2022年 | 147篇 |
2021年 | 190篇 |
2020年 | 107篇 |
2019年 | 71篇 |
2018年 | 73篇 |
2017年 | 82篇 |
2016年 | 62篇 |
2015年 | 67篇 |
2014年 | 43篇 |
2013年 | 50篇 |
2012年 | 17篇 |
2011年 | 7篇 |
2010年 | 8篇 |
2009年 | 14篇 |
2008年 | 14篇 |
2007年 | 10篇 |
2006年 | 9篇 |
2005年 | 8篇 |
2004年 | 4篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 8篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1985年 | 1篇 |
排序方式: 共有1164条查询结果,搜索用时 26 毫秒
81.
82.
A gauge repeatability and reproducibility (R&R) method is developed to assess the capability of a measurement system. Although gauge capability studies have received substantial attention, few studies have investigated attribute data despite their wide application in industry. The primary aim of this research is to develop a procedure, based on the generalized linear model, to evaluate the R&R of a measurement system for attribute data. To calculate repeatability of a system, the procedure integrates the iterative weighted least squares (IWLS) method and deviance analysis. The proposed procedure is applied to an inclusion measurement system to verify its adequacy to model the process capability. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
83.
Experimental studies of residence time distribution, fill factor, temperature, and melting profiles of thermoplastic resins are presented. Residence time distributions were determined as a function of throughput and screw speed. The melting of polypropylene and low density polyethylene in the entrance region was investigated. Fill factor and temperature profiles are reported. 相似文献
84.
Kee-Choon Kwon Soon-Ja Song Won-Man Park Sung-Pil Lyu 《IEEE transactions on nuclear science》1999,46(2):92-99
Testing and validation of the functions and performance of the digital instrumentation and control (I&C) system should be done prior to installation in nuclear power plants. The objective of the I&C Functional Test Facility (FTF) is to test and validate the functions of developed digital control and various monitoring systems. The FTF provides the simulated testing environment as an experimental test bed. The FTF software consists of a mathematical modeling program which simulates a three-loop 993 MWe pressurized water reactor and a supervisory program that comprises all the instructions necessary to run the FTF. The hardware equipment provides an interface between a host computer and a simple test panel or the developed target systems to be tested. The graphical user interface supports an easy and friendly interface between the FTF and users. It is implemented through a Picasso-3 graphic tool developed by the Halden Reactor Project. The FTF is applied to an advanced I&C system prototype, such as an automatic start-up intelligent control system, dynamic alarm system, accident identification system, and intelligent logic tracking system, to test its algorithm or performance. The results of the test show good operational performance of the FTF in normal and transient conditions 相似文献
85.
Small inverted repeats (small palindromes) on plasmids have been shown to mediate a recombinational rearrangement event in Escherichia coli leading to the formation of inverted dimers (giant palindromes). This recombinational rearrangement event is efficient and independent of RecA and RecBCD. In this report, we propose a cruciform-dumbbell model to explain the inverted dimer formation mediated by inverted repeats. In this model, the inverted repeats promote the formation of a DNA cruciform which is processed by an endonuclease into a linear DNA with two hairpin loops at its ends. Upon DNA replication, this linear dumbbell-like DNA is then converted to the inverted dimer. In support of this model, linear dumbbell DNA molecules with unidirectional origin of DNA replication (ColE1 ori ) have been constructed and shown to transform E.coli efficiently resulting in the formation of the inverted dimer. The ability of linear dumbbell DNA to transform E.coli suggests that the terminal loops may be important in bypassing the requirement of DNA supercoiling for initiation of replication of the ColE1 ori. 相似文献
86.
Hui-zhen Li Xiang-wen Chen Si-we Lyu 《Journal of Infrared, Millimeter and Terahertz Waves》2001,22(6):895-904
This paper describes a global optimization design for power combiner of solid-state millimeter wave source in rectangular wave- guide cavity. The algorithm can determine a neighborhood of the global optimum of an objective function. In this paper, the performance parameter are presents by combining efficiency, tuning range, frequency drift, and FM noise were done the objective functions respectively. And it is to calculate the global optima respectively. 相似文献
87.
88.
基于修正剑桥模型理论,推导了孔隙比e随土体当前应力变化的方程,同时比选了4组经典的描述渗透系数k随孔隙比变化的方程,选择了其中一组最佳的估算公式,编写ABAQUS用户子程序VOIDRI和USDFLD,以实现孔隙比和渗透系数随土体当前应力的变化。在此基础上,研究深基坑降水开挖所致的坑内外土体的变形、围护结构的变形及弯矩,得到以下结论:当考虑孔隙比随土体当前应力变化时,坑外地表沉降量、墙体的水平位移、地下连续墙的弯矩、坑底隆起量均大于孔隙比为定值时的情况;当考虑渗透系数随土体当前应力变化时,坑外地表沉降量、墙体的水平位移、地下连续墙的弯矩均小于渗透系数为定值时的情况,但同时考虑渗透系数和孔隙比变化情况时,其对坑底的隆起量的影响可以忽略不计。 相似文献
89.
90.
针对过山车难以精准定位的问题,本文提出了一种基于时间序列匹配的过山车定位方法。该方法首先使用动态时间规整(DTW)对惯性测量单元(IMU)的实测与仿真数据进行序列匹配,得到位置估计结果。之后将估计结果作为观测量,在误差状态卡尔曼滤波器(ESKF)中修正IMU预测结果,得到精准的定位结果。为了提高估计结果的准确度,本文提出了分段重组动态时间规整(SRDTW)算法,解决了DTW的匹配失真问题。使用本文方法对过山车进行了定位实验,结果表明,使用Z向加速度和俯仰角进行序列匹配可得到较为准确的估计结果;ESKF滤波后的平均定位误差可达0.24 m,较估计结果的定位误差减小45.6%。 相似文献