全文获取类型
收费全文 | 1823篇 |
免费 | 58篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 162篇 |
综合类 | 7篇 |
化学工业 | 494篇 |
金属工艺 | 62篇 |
机械仪表 | 51篇 |
建筑科学 | 38篇 |
能源动力 | 69篇 |
轻工业 | 145篇 |
石油天然气 | 2篇 |
无线电 | 153篇 |
一般工业技术 | 285篇 |
冶金工业 | 133篇 |
原子能技术 | 75篇 |
自动化技术 | 208篇 |
出版年
2024年 | 3篇 |
2023年 | 11篇 |
2022年 | 21篇 |
2021年 | 35篇 |
2020年 | 18篇 |
2019年 | 23篇 |
2018年 | 20篇 |
2017年 | 34篇 |
2016年 | 35篇 |
2015年 | 36篇 |
2014年 | 40篇 |
2013年 | 124篇 |
2012年 | 64篇 |
2011年 | 107篇 |
2010年 | 97篇 |
2009年 | 80篇 |
2008年 | 104篇 |
2007年 | 79篇 |
2006年 | 80篇 |
2005年 | 76篇 |
2004年 | 62篇 |
2003年 | 57篇 |
2002年 | 70篇 |
2001年 | 24篇 |
2000年 | 40篇 |
1999年 | 42篇 |
1998年 | 57篇 |
1997年 | 42篇 |
1996年 | 45篇 |
1995年 | 28篇 |
1994年 | 32篇 |
1993年 | 29篇 |
1992年 | 23篇 |
1991年 | 23篇 |
1990年 | 15篇 |
1989年 | 15篇 |
1988年 | 16篇 |
1987年 | 18篇 |
1986年 | 10篇 |
1985年 | 12篇 |
1984年 | 18篇 |
1983年 | 20篇 |
1982年 | 19篇 |
1981年 | 22篇 |
1980年 | 19篇 |
1979年 | 9篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 10篇 |
1974年 | 3篇 |
排序方式: 共有1884条查询结果,搜索用时 9 毫秒
21.
Makoto Okada Masayuki Iwasa Ken-ichiro Nakamatsu Kazuhiro Kanda Yuichi Haruyama Shinji Matsui 《Microelectronic Engineering》2009,86(4-6):673-675
A fluorinated self-assembled monolayer (F-SAM) is mainly used as the antisticking layer. To prevent the F-SAM coated on the nanoimprint lithography (NIL) mold from deteriorating, we propose a new form of nanoimprinting using a release-agent-coated resin. The results from measuring the surface free energy and observations by scanning probe microscopy (SPM) confirmed that the surface free energy, frictional force, and adhesion force of the release-agent spray-coated polymethylmethacrylate (PMMA) were lower than those of PMMA. To prove the release-agent spray-coated PMMA had a releasing effect, we tried to undertake thermal nanoimprinting on it using a mold without F-SAM. The pattern was clearly imprinted on the resin without any signs of adhesion. 相似文献
22.
Janis J Durham Joji Ogata Sadatoshi Nakajima Yoshihide Hagiwara Takayuki Shibamoto 《Journal of the science of food and agriculture》1999,79(10):1311-1314
The degradation of the organophosphorus pesticides malathion, chlorpyrifos, guthion, diazinon, methidathion and parathion in an aqueous extract of young green barley leaves (Hordeum vulgare L) was monitored by gas chromatography. Aqueous solutions of various amounts of freeze‐dried young barley leaves containing 5.75 mg l−1 of malathion were incubated at 37 °C and pH 7.4 over prolonged time periods. Over 95% of the malathion degraded in 4 h in a 3% (30 g l−1) solution of young green barley leaves. When the barley solution was autoclaved at 120 °C for 25 min prior to the addition of malathion, no degradation of malathion was observed. When 10 mg l−1 each of the above six pesticides was incubated in a 15% (150 g l−1) solution of young green barley leaves for 3 h at 37 °C and pH 7.4, malathion and chlorpyrifos degraded 100%, whereas parathion (75%), diazinon (54%), guthion (41%) and methidathion (23%) showed lesser degrees of degradation. © 1999 Society of Chemical Industry 相似文献
23.
Miida T. Hasegawa Y. Hagiwara T. Ohshiba H. 《Solid-State Circuits, IEEE Journal of》1991,26(12):1915-1919
The authors describe a charge coupled device (CCD) sense amplifier in a video delay line which overcomes the major limitations of conventional floating diffusion amplifier (FDA) technology, such as limited output voltage and operating temperature range. These advances are implemented with a switched-capacitor integrator (SCI) using an op amp with a newly developed output stage in a CMOS-CCD process. This circuit is effected within the constraints of 5-V operation by using negative pulses to reach the low channel potential of the CCD in the pinning region in the final gate of the CCD. The chip operates with 14.3-MHz clock and 5-V power supply, and can process a 1.0-Vp-p signal voltage under 1% distortion, and under 4% gain variation from -20 to 70°C 相似文献
24.
25.
26.
Youngha Chang Suguru Saito Masayuki Nakajima 《IEEE transactions on image processing》2007,16(2):329-336
Color transformation is the most effective method to improve the mood of an image, because color has a large influence in forming the mood. However, conventional color transformation tools have a tradeoff between the quality of the resultant image and the amount of manual operation. To achieve a more detailed and natural result with less labor, we previously suggested a method that performs an example-based color stylization of images using perceptual color categories. In this paper, we extend this method to make the algorithm more robust and to stylize the colors of video frame sequences. We present a variety of results, arguing that these images and videos convey a different, but coherent mood. 相似文献
27.
Shinsuke Kajioka Naoki Wakamiya Hiroki Satoh Kazuya Monden Masato Hayashi Susumu Matsui Masayuki Murata 《Ad hoc Networks》2011,9(5):911-927
To accommodate real-time multimedia application while satisfying application QoS requirements in a wireless ad-hoc network, we need QoS control mechanisms. In this paper, we propose a new routing mechanism to support real-time multimedia communication by efficiently utilize the limited wireless network capacity. Our mechanism considers a wireless ad-hoc network composed of nodes equipped with multiple network interfaces to each of which a different wireless channel can be assigned. By embedding information about channel usage in control messages of OLSRv2, each node obtains a view of topology and bandwidth information of the whole network. Based on the obtained information, a source node determines a logical path with the maximum available bandwidth to satisfy application QoS requirements. Through simulation experiments, we confirmed that our proposal effectively routed multimedia packets over a logical path avoiding congested links. As a result, the load on a network is well distributed and the network can accommodate more sessions than QOLSR. We also conducted practical experiments using wireless ad-hoc relay nodes with four network interfaces and verified the practicality of our proposal. 相似文献
28.
This paper proposes 2-D variable IIR digital filter structures with a small amount of calculations for coefficient update. The proposed realization method uses the 2-D parallel allpass structure derived from the separable denominator 2-D filter as the prototype structure for 2-D variable digital filters. In order to reduce the amount of calculations, all the redundant first-order complex allpass sections are combined by modularization of the variable structure. Furthermore, we can realize a very compact variable structure with a minimal number of first-order complex allpass sections by combining complex allpass sections with their complex conjugate allpass sections. Comparison of the calculation loads of the variable structures is presented to demonstrate that the amount of calculations for coefficient update of the proposed variable structure is far less than that of the original and the modular variable structure. 相似文献
29.
Onur Alparslan Shin’ichi Arakawa Masayuki Murata 《Photonic Network Communications》2011,22(2):172-179
One of the difficulties with optical packet switched (OPS) networks is buffering optical packets in the network. The only
available solution that can currently be used for buffering in the optical domain is using long fiber lines called fiber delay
lines (FDLs), which have severe limitations. Moreover, the research on optical RAM presently being done is not expected to
achieve a large capacity soon. However, the burstiness of Internet traffic causes high packet drop rates and low utilization
in very small buffered OPS networks. We therefore propose a new node-based pacing algorithm for decreasing burstiness. We
show that by applying some simple pacing at the edge or core backbone nodes, the performance of very small optical RAM buffered
core OPS networks with variable-length packets can be notably increased. 相似文献
30.