全文获取类型
收费全文 | 569749篇 |
免费 | 7804篇 |
国内免费 | 1807篇 |
专业分类
电工技术 | 10303篇 |
综合类 | 487篇 |
化学工业 | 85423篇 |
金属工艺 | 20596篇 |
机械仪表 | 16595篇 |
建筑科学 | 15374篇 |
矿业工程 | 2093篇 |
能源动力 | 15185篇 |
轻工业 | 55444篇 |
水利工程 | 5123篇 |
石油天然气 | 5671篇 |
武器工业 | 21篇 |
无线电 | 72030篇 |
一般工业技术 | 107920篇 |
冶金工业 | 105545篇 |
原子能技术 | 9802篇 |
自动化技术 | 51748篇 |
出版年
2021年 | 4100篇 |
2019年 | 3812篇 |
2018年 | 6100篇 |
2017年 | 6202篇 |
2016年 | 6614篇 |
2015年 | 4977篇 |
2014年 | 8325篇 |
2013年 | 26579篇 |
2012年 | 14318篇 |
2011年 | 20238篇 |
2010年 | 15750篇 |
2009年 | 17989篇 |
2008年 | 18882篇 |
2007年 | 19149篇 |
2006年 | 16880篇 |
2005年 | 15817篇 |
2004年 | 15255篇 |
2003年 | 14966篇 |
2002年 | 14263篇 |
2001年 | 14470篇 |
2000年 | 13542篇 |
1999年 | 14223篇 |
1998年 | 32894篇 |
1997年 | 23751篇 |
1996年 | 18799篇 |
1995年 | 14488篇 |
1994年 | 12997篇 |
1993年 | 12487篇 |
1992年 | 9483篇 |
1991年 | 9059篇 |
1990年 | 8585篇 |
1989年 | 8344篇 |
1988年 | 7982篇 |
1987年 | 6795篇 |
1986年 | 6681篇 |
1985年 | 8033篇 |
1984年 | 7540篇 |
1983年 | 6720篇 |
1982年 | 6131篇 |
1981年 | 6229篇 |
1980年 | 5809篇 |
1979年 | 5790篇 |
1978年 | 5524篇 |
1977年 | 6502篇 |
1976年 | 8761篇 |
1975年 | 4653篇 |
1974年 | 4482篇 |
1973年 | 4381篇 |
1972年 | 3527篇 |
1971年 | 3167篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Many current implementations of protocols such as the Transmission Control Protocol/Internet Protocol (TCP/IP) are inefficient because data are often accessed more frequently than necessary. Three techniques that reduce the need for memory bandwidth are proposed. The techniques are copy-on-write, page remapping, and single-copy. Afterburner, a network-independent card that provides the services that are necessary for a single-copy protocol stack, is described. The card has 1 MByte of local buffers and provides a simple interface to a variety of network link adapters, including HIPPI and asynchronous transfer mode (ATM). Afterburner can support transfers to and from the link adapter card at rates up to 1 Gbit/s. An implementation of TCP/IP that uses the features provided by Afterburner to reduce the movement of data to a single copy is discussed. Measurements of the end-to-end performance of Afterburner and the single-copy implementation of TCP/IP are presented 相似文献
92.
93.
Garner H.R. Balog R.P. Luebke K.J. 《IEEE engineering in medicine and biology magazine》2002,21(4):123-125
Given the enormous size of the genome and that there are potentially many other types of measurements we need to do to understand it, it has become necessary to pick and choose one's targets to measure because it is still impossible to evaluate the entire genome all at once. What has emerged is a need to have rapidly customizable microarrays. There are two dominant methods to accomplish custom microarray synthesis, Affymetrix-like microarrays manufactured using light projection rather than semiconductor-like masks used by Affymetrix to mass manufacture their GeneChip/sup TM/ arrays now, or the ink-jet printing method employed by Agilent. The manufacture of these custom Affymetrix-like microarrays can now be done on a digital optical chemistry (DOC) machine developed at the University of Texas Southwestern Medical Center, and this method offers much higher feature numbers and feature density than is possible with ink-jet printed arrays. On a microarray, each feature contains a single genetic measurement. The initial DOC prototype has been described in several publications, but that has now led to a second-generation machine. This machine reliably produces a number of arrays daily, has been deployed against a number of biomedical questions, is being used in new ways and has also led to a number of spin-off technologies. 相似文献
94.
Metal Science and Heat Treatment - 相似文献
95.
Rapeseed protein concentrate (RC), prepared with 2% hexameta-phosphate, was tested for its functionality and performance in some foods. The RC had good nitrogen solubility, fat absorption, emulsification, and whipping capacities but poor water absorption and gelling properties. It increased the emulsion stability, and protein but lowered the fat content of wieners. It also increased the cooking yield, reduced the shrinkage and tenderized meat patties. Results were similar to soybean isolate except for the poorer color and flavor. The cooking yield of RC supplemented wieners was less than the all-meat control and soybean-supplemented wieners. A 9% RC dispersion mixed with an equal volume of eggwhite produced a meringue of comparable stability and texture to that of eggwhite alone. 相似文献
96.
A. A. Konstantinov N. V. Kurenkov A. B. Malinin T. E. Sazonova S. V. Sepman 《Atomic Energy》1989,67(3):696-698
Translated from Atomnaya Énergiya, Vol. 67, No. 3, pp. 215–216, September, 1989. 相似文献
97.
98.
J. Perahia comments on the paper by J. S. Hsu (see ibid., vol.16, p.192-7, 2001) and expands on the case of a two stator three phase squirrel cage induction machine where one stator housing is stationary and other stator housing is mounted on a worm gear assembly. The original author replies to the comments 相似文献
99.
An investigation into the effects of pressure (helium gas) on the isothermal fluid behavior includes: (1) the effect of pressure on the rate of melting and coking as evidenced by the rate constants k(melt) and k(coke); (2) the effect of pressure on the energies of activation of melting and coking; (3) the effects of pressure on the characteristic times; (4) the effects of pressure on the maximum isothermal fluidity. Results from the effects of pressure on k(melt) revealed that it was generally the high total sulfur, low nitrogen, low reactives/mineral matter ratio, medium rank coals which show the greatest increase in k(melt), whereas the highest rank coals show the least decrease in k(coke). The energies of activation of melting and coking were not significantly affected by pressure. The investigation also reveals increases or decreases in the respective times of softening, maximum fluidity, resolidification and total time of fluid behavior under isothermal pressurized conditions. There appears the possibility that these shifts may be rank dependent. Additionally, the lower rank coals show the largest relative increase in their fluidities when subjected to pressure. Empirical relationships were derived in order to quantitatively predict the maximum isothermal fluidity for most (fluid) coals at a given pressure. 相似文献
100.