全文获取类型
收费全文 | 1211篇 |
免费 | 56篇 |
国内免费 | 29篇 |
专业分类
电工技术 | 90篇 |
综合类 | 16篇 |
化学工业 | 352篇 |
金属工艺 | 51篇 |
机械仪表 | 61篇 |
建筑科学 | 25篇 |
矿业工程 | 2篇 |
能源动力 | 51篇 |
轻工业 | 140篇 |
水利工程 | 6篇 |
石油天然气 | 11篇 |
无线电 | 92篇 |
一般工业技术 | 181篇 |
冶金工业 | 15篇 |
原子能技术 | 77篇 |
自动化技术 | 126篇 |
出版年
2024年 | 3篇 |
2023年 | 9篇 |
2022年 | 13篇 |
2021年 | 21篇 |
2020年 | 14篇 |
2019年 | 22篇 |
2018年 | 39篇 |
2017年 | 29篇 |
2016年 | 34篇 |
2015年 | 26篇 |
2014年 | 26篇 |
2013年 | 81篇 |
2012年 | 52篇 |
2011年 | 82篇 |
2010年 | 51篇 |
2009年 | 57篇 |
2008年 | 62篇 |
2007年 | 48篇 |
2006年 | 46篇 |
2005年 | 57篇 |
2004年 | 37篇 |
2003年 | 44篇 |
2002年 | 44篇 |
2001年 | 19篇 |
2000年 | 29篇 |
1999年 | 24篇 |
1998年 | 32篇 |
1997年 | 27篇 |
1996年 | 22篇 |
1995年 | 22篇 |
1994年 | 22篇 |
1993年 | 21篇 |
1992年 | 13篇 |
1991年 | 17篇 |
1990年 | 12篇 |
1989年 | 9篇 |
1988年 | 12篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 12篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 10篇 |
1979年 | 9篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1975年 | 3篇 |
1974年 | 3篇 |
排序方式: 共有1296条查询结果,搜索用时 15 毫秒
31.
The effect of low temperature post weld heat treatment on the tensile strength and bend test properties of dissimilar friction welds between titanium and AISI 304L stainless steel joints is investigated. Post weld heat treatment at temperatures less than 873 K has no effect on joint tensile strength properties, but markedly improves bend test properties. The highest bend angle is produced using a post-weld heat treatment at 773 K for 1 h (the Larson-Miller parameter corresponding to this treatment is 15.5×103 K h–1). Low temperature heat treatment improves bend ductility, because stress relaxation occurs with minimal increase in the transition region width at the bondline region. Dissimilar joint bend testing properties decrease markedly when the width of the transition region exceeds 1–2 m. An explanation for the detrimental effect of thick transition regions at the joint interface region on the mechanical properties of dissimilar joints is proposed. It is suggested that the development of significant triaxial stress due to the constraint imposed by large, needle-shaped intermetallic particles promotes premature joint failure in joints containing thick transition regions. 相似文献
32.
Bei Wang Xingyu Wang Akio Ikeda Takashi Nagamine Hiroshi Shibasaki Masatoshi Nakamura 《Artificial Life and Robotics》2011,16(2):243-247
Electroencephalogram (EEG) interpretation is important for the investigation of brain diseases. In this study, an automatic
technique was developed to detect the topographical distribution of EEG rhythms. In order to obtain the topographical distribution,
the amplitude of the EEG rhythm was analyzed based on the referential derivation where the reference potential was adjusted
iteratively. The result of the automatic detection of the topographical distribution was helpful in highlighting the EEG rhythms
of interest for automatic EEG interpretation. The technique developed has application significance for real clinics. 相似文献
33.
Weblogs are increasingly popular modes of communication and they are frequently used as mediums for emotional expression in the ever changing online world. This work uses blogs as object and data source for Chinese emotional expression analysis. First, a textual emotional expression space model is described, and based on this model, a relatively fine-grained annotation scheme is proposed for manual annotation of an emotion corpus. In document and paragraph levels, emotion category, emotion intensity, topic word and topic sentence are annotated. In sentence level, emotion category, emotion intensity, emotional keyword and phrase, degree word, negative word, conjunction, rhetoric, punctuation, objective or subjective, and emotion polarity are annotated. Then, using this corpus, we explore these linguistic expressions that indicate emotion in Chinese, and present a detailed data analysis on them, involving mixed emotions, independent emotion, emotion transfer, and analysis on words and rhetorics for emotional expression. 相似文献
34.
A molecular valve, consisting of poly(acrylic acid) gel-coated Au mesh, was developed based on volume change of the gel in response to cation concentration. The valve closed when concentration of cations such as H+, Na+, K+, Ca2+, Cu2+, or Al3+ was low, whereas opened upon increase in its concentration. The valve re-closed when water was flowed. The concentration where the valve opens was found to increase in the order of Al3+, Ca2+, and Na+ (2 × 10−4, 5 × 10−4, and 6 × 10−3 M, respectively). The response to Cu2+ ion showed similar behaviour, but the opening concentration was ca. 2 × 10−4 M, which is lower than that of Ca2+ ion. The valve appeared to close over the pH range from 3 to 12, whereas to open below and above it. The fastest response time to open the valve (less than 1 min) was obtained for a solution of pH 1–2. The valve showed repeatability at least 25 cycles upon successive loading of a solution of pH 2 and water. Effects of anions and pressure were also studied. 相似文献
35.
Yasushi Hosokawa Daiki Urata Akio Doi Toyoo Takata Yoshihiko Abe 《Artificial Life and Robotics》2017,22(3):346-356
The virtual diving experience learning system of “Ama”, Japanese traditional female divers, has been developed to simulate how divers move in a virtual space using the diving interface and utilizing an accelerometer and a gyroscope. This interface not only detects the diving motion but also outputs the movement. Diving motion is shown in the ways of hand motion while standing. Although this makes it possible for a learner to understand the divers’ actions more clearly, this system’s difficulty is in visualizing a divers’ actions including their hands or bodies. Therefore, our study focuses on developing the operation system to reproduce actual ways of Amas’ diving with a virtual human body in a virtual space. First, the motion capture was done in an underwater condition. In the next process, the virtual human body was created. Finally, with the motion viewer, the more vivid actions of the Ama were successfully reproduced much more than in previous attempts. Using this system, the effectiveness of the Amas’ movement learning was confirmed, because a learner practices Amas’ movement. 相似文献
36.
37.
In this paper the ensemble of independent factor analyzers (EIFA) is proposed. This new statistical model assumes that each data point is generated by the sum of outputs of independently activated factor analyzers. A maximum likelihood (ML) estimation algorithm for the parameter is derived using a Monte Carlo EM algorithm with a Gibbs sampler. The EIFA model is applied to natural image data. With the progress of the learning, the independent factor analyzers develop into feature detectors that resemble complex cells in mammalian visual systems. Although this result is similar to the previous one obtained by independent subspace analysis, we observe the emergence of complex cells from natural images in a more general framework of models, including overcomplete models allowing additive noise in the observables. 相似文献
38.
Akira Masutani Tony Roberts Bettina Schüller Nadine Hollfelder Pinar Kilickiran Akira Sakaigawa Gabriele Nelles Akio Yasuda 《Journal of the Society for Information Display》2008,16(1):137-141
Abstract— A polymer‐dispersed liquid‐crystal (PDLC) matrix template embedded with nano/microparticles can be backfilled/infiltrated with a dye‐doped liquid crystal for a paper‐like reflective display. In this way, a desirable degree of diffusion can be realized to reduce the viewing‐angle dependency of a gain reflector and metallic glare without changing other electro‐optical properties. 相似文献
39.
Leonard Barolli Akio Koyama Arjan Durresi Giuseppe De Marco 《Information Systems Frontiers》2006,8(4):297-306
Due to the opportunities provided by the Internet, more and more people are taking advantage of distance learning courses
and during the last few years enormous research efforts have been dedicated to the development of distance learning systems.
So far, many e-learning systems are proposed and used practically. However, in these systems the e-learning completion rate
is about 30%. One of the reasons is the low study desire when the learner studies the learning materials. In this research,
we propose an interactive Web-based e-learning system. The purpose of our system is to increase the e-learning completion
rate by stimulating learner’s motivation. The proposed system has three subsystems: the learning subsystem, learner support
subsystem, and teacher support subsystem. The learning subsystem improves the learner’s study desire. The learner support
subsystem supports the learner during the study, and the teacher support subsystem supports the teacher to get the learner’s
study state. To evaluate the proposed system, we developed several experiments and surveys. By using new features such as:
display of learner’s study history, change of interface color, encourage function, ranking function, self-determination of
the study materials, and grouping of learners, the proposed system can increase the learning efficiency.
相似文献
Giuseppe De MarcoEmail: |
40.
During iron-carbon eutectic solidification, the coefficients for partition of a third element between the eutectic liquid and its solid were evaluated thermodynamically. The coefficientk
M
A/L
for the equilibrium partition of the third element (M) between austenite and liquid iron largely depended on the interaction between carbon and the third element and a simplified method for the evaluation ofk
M
A/L
was introduced. The coefficients,K
S andK
M, for the partition of the element between the eutectic liquid and its solid in the stable and metastable eutectic solidification, respectively, were also calculated fromk
M
A/L
and the coefficientk
M
C/A
for the equilibrium partition of the element between cementite and austenite. It was indicated by the thermodynamics of the free energy for the co-existing phases that the effect of a third element on graphitization occurring during eutectic solidification was related quantitatively to the value of K which was represented byK
S-K
M. The effect of a third element on the difference between the stable and metastable eutectic temperatures and on the carbon activity of liquid iron was closely related to K or the equilibrium partition coefficient,k
M
C/A
. 相似文献