全文获取类型
收费全文 | 55670篇 |
免费 | 4994篇 |
国内免费 | 2426篇 |
专业分类
电工技术 | 3153篇 |
技术理论 | 7篇 |
综合类 | 3600篇 |
化学工业 | 9481篇 |
金属工艺 | 3263篇 |
机械仪表 | 3563篇 |
建筑科学 | 3982篇 |
矿业工程 | 1751篇 |
能源动力 | 1723篇 |
轻工业 | 3492篇 |
水利工程 | 889篇 |
石油天然气 | 3388篇 |
武器工业 | 535篇 |
无线电 | 6527篇 |
一般工业技术 | 7043篇 |
冶金工业 | 2825篇 |
原子能技术 | 764篇 |
自动化技术 | 7104篇 |
出版年
2024年 | 303篇 |
2023年 | 1041篇 |
2022年 | 1766篇 |
2021年 | 2530篇 |
2020年 | 1881篇 |
2019年 | 1518篇 |
2018年 | 1771篇 |
2017年 | 1989篇 |
2016年 | 1813篇 |
2015年 | 2318篇 |
2014年 | 2994篇 |
2013年 | 3525篇 |
2012年 | 3757篇 |
2011年 | 3963篇 |
2010年 | 3363篇 |
2009年 | 3178篇 |
2008年 | 3088篇 |
2007年 | 2930篇 |
2006年 | 2829篇 |
2005年 | 2407篇 |
2004年 | 1719篇 |
2003年 | 1477篇 |
2002年 | 1465篇 |
2001年 | 1266篇 |
2000年 | 1261篇 |
1999年 | 1270篇 |
1998年 | 1060篇 |
1997年 | 905篇 |
1996年 | 823篇 |
1995年 | 642篇 |
1994年 | 549篇 |
1993年 | 365篇 |
1992年 | 298篇 |
1991年 | 217篇 |
1990年 | 191篇 |
1989年 | 152篇 |
1988年 | 124篇 |
1987年 | 65篇 |
1986年 | 69篇 |
1985年 | 38篇 |
1984年 | 33篇 |
1983年 | 28篇 |
1982年 | 31篇 |
1981年 | 20篇 |
1980年 | 13篇 |
1979年 | 10篇 |
1978年 | 3篇 |
1976年 | 11篇 |
1975年 | 3篇 |
1973年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Li-Pen Yuan Chin-Chi Teng Sung-Mo Kang 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》1998,6(1):65-73
In this paper, we present a new statistical technique for estimation of average power dissipation in digital circuits. The present parametric statistical technique estimates the average power based on the assumption that the power distribution can be characterized by a preassumed function. Large error can incur when the assumption is not met. On the other hand, the existing nonparametric technique, although accurate, is too conservative and requires a large sample size in order to achieve convergence. For a good tradeoff between simulation accuracy and computational efficiency, we propose a new nonparametric technique using the properties of the order statistics. It is generally applicable to any type of circuit irrespective of its power distribution function. Compared to the existing nonparametric technique, it is much more computationally efficient since it requires a much smaller sample size to achieve the same accuracy specification. This new technique is implemented in the distribution-independent power estimation tool (DIPE). DIPE is empirically demonstrated to be more robust and accurate than the parametric technique 相似文献
62.
Business process redesign (BPR) has been widely touted as a means for leveraging the power of information technology to change business processes radically, resulting in substantial improvements in organizational effectiveness and efficiency. This study represents an early attempt at examining the strategic nature of the phenomenon. Because BPR is radical change and has the ability to alter both the competitive and operational nature of the corporation, it is critical that BPR be coordinated with corporate strategy. Through a survey of information system executives, the relationships between corporate competitive strategy and three types of BPR – intrafunctional, interfunctional and interorganizational – were examined. It was found that organizations following a cost strategy tended to do more BPR projects on interfunctional processes. Furthermore, the positive effect of a cost strategy on interfunctional BPR was found to be strengthened by the degree of integration of IS and business planning. It was also found that while interorganizational BPR was not related to a specific strategy, it was strongly related directly with IS–business planning integration. 相似文献
63.
A clinical case control study to identify prognostic factors present at hospital admission associated with early sequelae and fatal outcome of acute Japanese encephalitis (JE) was carried out in Gusi county, Henan Province, central China from June to September 1991. A total of 70 patients with laboratory-confirmed acute JE were studied, of whom 3 cases died and 33 cases had neurological or psychiatric sequelae at the end of three months follow-up. The results showed that acute JE at younger age, with higher body temperature, high white cell count in CSF, and deep coma present at hospital admission were markers for unfavorable outcomes (sequelae or fatal). A history of the vaccination was not correlated with the early sequelae and fatal outcome of the disease. The paper suggests that early diagnosis and treatment and universal JE vaccination for all susceptible populations are keys for decreasing incidence of sequelae and fatal outcome of acute JE. 相似文献
64.
65.
66.
聚碳硅烷的分子量分布与可纺性研究 总被引:6,自引:1,他引:5
阐述了聚碳烷的合成及其分子量分布,讨论了高低分子含量对聚碳硅烷熔点及可纺性的影响,而且提出了分子量分布的控制标准与方法。 相似文献
67.
本文结合实际资料,对内蒙古赤峰热水镇温泉天然气的地球化学特征进行了分析和研究。结果表明:上述天然气由多种成因气体组合而成。其中He属壳源放射性成因,CO_2属有机成因,CH_4属无机合成,N_2属大气成因。 相似文献
68.
One requirement in designing and operating and operating system is to minimize the moisture change in stored grain. Moisture transfer during the aeration process is generally believed to be caused by the partial pressure difference between water in grain and water in air (P3-P4). A mathematical model was developed for rough rice, which predicts the partial pressure difference under various grain and ambient conditions. Observations of moisture change over 10 aeration tests confirmed the good correlation between sorption phenomena and partial pressure differences. Studies indicated that air relative humidity, air temperature, grain temperature and grain moisture are significant factors influencing the partial pressure differences and, thus, affecting 相似文献
69.
有机发光器件(OLED)具有固体平板化的优点,用OLED制做平板显示器不仅重量轻和功耗低,而且能实现低成本的彩色大屏幕显示。本文从有机发光器件的原理出发,阐述了有机发光器件平板显示器的三色象元的一些实现方案和目前的发展状况,并对它们的基本结构及技术特点进行了比较。 相似文献
70.
McIntyre H. Wendell D. Lin K.J. Kaushik P. Seshadri S. Wang A. Sundararaman V. Ping Wang Song Kim Hsu W.-J. Hee-Choul Park Levinsky G. Jiejun Lu Chirania M. Heald R. Lazar P. Dharmasena S. 《Solid-State Circuits, IEEE Journal of》2005,40(1):52-59
A 4-MB L2 data cache was implemented for a 64-bit 1.6-GHz SPARC(r) RISC microprocessor. Static sense amplifiers were used in the SRAM arrays and for global data repeaters, resulting in robust and flexible timing operation. Elimination of the global clock grid over the SRAM array saves power, enabled by combining the clock information with array select signals. Redundancy was implemented flexibly, with shift circuits outside the main data array for area efficiency. The chip integrates 315 million transistors and uses an 8-metal-layer 90-nm CMOS process. 相似文献