全文获取类型
收费全文 | 36333篇 |
免费 | 1300篇 |
国内免费 | 63篇 |
专业分类
电工技术 | 372篇 |
综合类 | 29篇 |
化学工业 | 7236篇 |
金属工艺 | 725篇 |
机械仪表 | 738篇 |
建筑科学 | 1964篇 |
矿业工程 | 114篇 |
能源动力 | 1054篇 |
轻工业 | 2883篇 |
水利工程 | 430篇 |
石油天然气 | 117篇 |
武器工业 | 5篇 |
无线电 | 2475篇 |
一般工业技术 | 6114篇 |
冶金工业 | 6598篇 |
原子能技术 | 268篇 |
自动化技术 | 6574篇 |
出版年
2023年 | 214篇 |
2022年 | 440篇 |
2021年 | 683篇 |
2020年 | 463篇 |
2019年 | 617篇 |
2018年 | 780篇 |
2017年 | 695篇 |
2016年 | 833篇 |
2015年 | 757篇 |
2014年 | 1040篇 |
2013年 | 2372篇 |
2012年 | 1681篇 |
2011年 | 2091篇 |
2010年 | 1652篇 |
2009年 | 1547篇 |
2008年 | 1800篇 |
2007年 | 1774篇 |
2006年 | 1591篇 |
2005年 | 1439篇 |
2004年 | 1174篇 |
2003年 | 1122篇 |
2002年 | 1051篇 |
2001年 | 702篇 |
2000年 | 549篇 |
1999年 | 595篇 |
1998年 | 583篇 |
1997年 | 574篇 |
1996年 | 549篇 |
1995年 | 572篇 |
1994年 | 525篇 |
1993年 | 510篇 |
1992年 | 500篇 |
1991年 | 288篇 |
1990年 | 418篇 |
1989年 | 389篇 |
1988年 | 319篇 |
1987年 | 355篇 |
1986年 | 310篇 |
1985年 | 418篇 |
1984年 | 416篇 |
1983年 | 318篇 |
1982年 | 295篇 |
1981年 | 281篇 |
1980年 | 269篇 |
1979年 | 270篇 |
1978年 | 247篇 |
1977年 | 225篇 |
1976年 | 206篇 |
1975年 | 194篇 |
1974年 | 173篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
The enzymic activity of the GTP-dependent acyl-CoA synthase isolated from rat liver mitochondria is affected by removal and
addition of lecithin (3). Purified preparations of this enzyme contain bound lecithin. In this presentation the nature of
the lecithin-protein interaction is examined. From binding measurements at different temperatures it is possible to postulate
which type of secondary valence bonds is holding the protein and lecithin together.
Presented at AOCS Meeting, Chicago, October 1967. 相似文献
103.
The mechanisms and kinetics of radical entry in emulsion polymerizations utilizing redox initiation are investigated using polymerization rate data obtained by reaction calorimetry and electrospray mass spectroscopy analysis of initiator-derived aqueous-phase products. These data have been used to evaluate an initiation scheme for redox-initiated emulsion polymerizations of common monomers such as styrene and methyl methacrylate based around the oxidant, tert-butyl hydroperoxide. Redox initiators are broadly classed by the solubility of their radical products: Hydrophilic radicals enter by propagating to a critical degree of polymerization to become surface-active whilst more hydrophobic radicals may enter particles directly. When direct entry is applicable (the hydrophobic case), initiation efficiency will always be very high. 相似文献
104.
105.
Liu Xinke Kao Evan Haraldsson Henrik Ballweber Megan Martin Alastair Li Youxiang Wang Yuting Saloner David 《Magma (New York, N.Y.)》2021,34(5):659-666
Magnetic Resonance Materials in Physics, Biology and Medicine - To determine the intra-individual flow variation in serially acquired studies, and the influence of this variation on subsequent... 相似文献
106.
Shaohui Mei Genliang Guan Zhiyong Wang Shuai Wan Mingyi He David Dagan Feng 《Pattern recognition》2015
The rapid growth of video data demands both effective and efficient video summarization methods so that users are empowered to quickly browse and comprehend a large amount of video content. In this paper, we formulate the video summarization task with a novel minimum sparse reconstruction (MSR) problem. That is, the original video sequence can be best reconstructed with as few selected keyframes as possible. Different from the recently proposed convex relaxation based sparse dictionary selection method, our proposed method utilizes the true sparse constraint L0 norm, instead of the relaxed constraint L2,1 norm, such that keyframes are directly selected as a sparse dictionary that can well reconstruct all the video frames. An on-line version is further developed owing to the real-time efficiency of the proposed MSR principle. In addition, a percentage of reconstruction (POR) criterion is proposed to intuitively guide users in obtaining a summary with an appropriate length. Experimental results on two benchmark datasets with various types of videos demonstrate that the proposed methods outperform the state of the art. 相似文献
107.
108.
109.
David Hocker Yicong Zheng Robert Kosut Todd Brun Herschel Rabitz 《Quantum Information Processing》2016,15(11):4361-4390
There is a rich variety of physics underlying the fundamental gating operations for quantum information processing (QIP). A key aspect of a QIP system is how noise may enter during quantum operations and how suppressing or correcting its effects can best be addressed. Quantum control techniques have been developed to specifically address this effort, although a detailed classification of the compatibility of controls schemes with noise sources found in common quantum systems has not yet been performed. This work numerically examines the performance of modern control methods for suppressing decoherence in the presence of noise forms found in viable quantum systems. The noise-averaged process matrix for controlled one-qubit and two-qubit operations are calculated across noise found in systems driven by Markovian open quantum dynamics. Rather than aiming to describe the absolute best control scheme for a given physical circumstance, this work serves instead to classify quantum control behavior across a large class of noise forms so that opportunities for improving QIP performance may be identified. 相似文献
110.