全文获取类型
收费全文 | 1293篇 |
免费 | 28篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 78篇 |
化学工业 | 318篇 |
金属工艺 | 55篇 |
机械仪表 | 25篇 |
建筑科学 | 22篇 |
能源动力 | 68篇 |
轻工业 | 116篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 83篇 |
一般工业技术 | 250篇 |
冶金工业 | 160篇 |
原子能技术 | 40篇 |
自动化技术 | 106篇 |
出版年
2023年 | 6篇 |
2022年 | 16篇 |
2021年 | 16篇 |
2020年 | 13篇 |
2019年 | 10篇 |
2018年 | 19篇 |
2017年 | 17篇 |
2016年 | 20篇 |
2015年 | 14篇 |
2014年 | 28篇 |
2013年 | 107篇 |
2012年 | 52篇 |
2011年 | 81篇 |
2010年 | 54篇 |
2009年 | 64篇 |
2008年 | 78篇 |
2007年 | 55篇 |
2006年 | 40篇 |
2005年 | 40篇 |
2004年 | 45篇 |
2003年 | 43篇 |
2002年 | 41篇 |
2001年 | 25篇 |
2000年 | 21篇 |
1999年 | 36篇 |
1998年 | 70篇 |
1997年 | 57篇 |
1996年 | 35篇 |
1995年 | 25篇 |
1994年 | 29篇 |
1993年 | 21篇 |
1992年 | 14篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 12篇 |
1988年 | 14篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 4篇 |
排序方式: 共有1324条查询结果,搜索用时 15 毫秒
31.
This paper proposes a new topological designmethod, named BXCQ, which optimizes logical networkconfiguration while guaranteeing Quality-of-Service(QoS) requirements for each service class in an ATMnetwork. The BXCQ method determines the optimum logicalnetwork topology associated with each service class soas to minimize network cost. In our previously proposedFull-Net architecture these different logical topologies can be suitably mapped at the sametime on the same ATM physical network by using theVirtual Channel Handler (VCH) to create differentlogical interconnection networks. The BXCQ method allows us to clarify the relations between multimediatraffic characteristics and desirable logical networkconfigurations in Full-Net. Evaluation results suggestthat a service class that is bursty, delay tolerant, and cell loss sensitive with small demandshould be supported by a loop-like topology. This studywill be useful for designing flexible and cost-effectivemultimedia networks that can also adapt to not-yet-known services. 相似文献
32.
Masatsugu Nagai Yozo Fujino Hiroki Yamaguchi Eiji Iwasaki 《Canadian Metallurgical Quarterly》2004,9(5):444-452
This paper describes the feasibility of 1,400 m steel cable-stayed bridges from both structural and economic viewpoints. Because the weight of a steel girder strongly affects the total cost of the bridge, the writers present a procedure to obtain a minimum weight for a girder that ensures safety against static and dynamic instabilities. For static instability, elastoplastic, finite-displacement analysis under in-plane load and elastic, finite-displacement analysis under displacement-dependent wind load are conducted; for dynamic instability, multimodal flutter analysis is carried out. It is shown that static critical wind velocity of lateral torsional buckling governs the dimension of the girder. Finally, the writers briefly compare a cable-stayed bridge with suspension bridge alternatives. 相似文献
33.
BaO—CaO—Na2O—CaF2—Cr2O3渣系的不锈钢脱磷 总被引:2,自引:1,他引:2
测定了1500℃时磷在BaO-CaO-Na2O-CaF2-Cr2O3渣子和0.12C-0.71Si-18Cr不锈钢熔体之间的分配比,试验结果表明,该渣系的不锈钢脱磷能力比CaO基渣好,与BaO基渣相当。 相似文献
34.
Shigeo Asai Kunihito Koumoto Yushu Matsushita Eiji Yashima Masahiko Morinaga Kunihiko Takeda 《Science and Technology of Advanced Materials》2013,14(5):421-433
The center of excellence (COE) titled ‘The Creation of Nature-Guided Materials Processing’ has been established in Nagoya University as the 21st Century COE Program supported by Ministry of Education, Culture, Sports, Science and Technology. In the Nature COE, various activities on the education and research are being performed through learning the laws of nature, namely, methods of attaining ‘appearance of the maximum function under the minimum substance and energy consumption’, which the nature and living organisms have acquired through their evolution in long period. Together with such educational programs for PhD students as research incentive, oversea training, and external evaluation programs, an ‘Open-Cluster Program’ was originated for promoting researches proposed by research groups consisting of young researchers in and out of the university and also for fostering them.The researches are being advanced on materials used for living bodies, mimicking structures which nature or living bodies are forming, and producing materials by mimicking processes to form the structures observed in the nature or the living bodies. In this COE, these researches are conducted by four groups to extend the processes observed in the natural world to a new type of processing, that is, thoroughly examined and rationalized by plunging a scalpel of engineering and to establish a new academic field of materials science and engineering. 相似文献
35.
Eiji Kamio Tomoki Yasui Yu Iida Jian Ping Gong Hideto Matsuyama 《Advanced materials (Deerfield Beach, Fla.)》2017,29(47)
Highly robust ion gels, termed double‐network (DN) ion gels, composed of inorganic/organic interpenetrating networks and a large amount of ionic liquids (ILs), are fabricated. The DN ion gels with an 80 wt% IL content show extraordinarily high mechanical strength: more than 28 MPa of compressive fracture stress. In the DN ion gel preparation, a brittle inorganic network of physically bonded silica nanoparticles and a ductile organic network of polydimethylacrylamide (PDMAAm) are formed in the IL. Because of the different reaction mechanisms of the inorganic/organic networks, the DN ion gels can be formed by an easy and free‐shapeable one‐pot synthesis. They can be prepared in a controllable manner by manipulating the formation order of the inorganic and organic networks via not only multistep but also single‐step processes. When silica particles form a network prior to the PDMAAm network formation, DN ion gels can be prepared. The brittle silica particle network in the DN ion gel, serving as sacrificial bonds, easily ruptures under loading to dissipate energy, while the ductile PDMAAm network maintains the shape of the material by the rubber elasticity. Given the reversible physical bonding between the silica particles, the DN ion gels exhibit a significant degree of self‐recovery by annealing. 相似文献
36.
In clustering algorithms, it is usually assumed that the number of clusters is known or given. In the absence of such a priori information, a procedure is needed to find an appropriate number of clusters. This paper presents a clustering algorithm that incorporates a mechanism for finding the appropriate number of clusters as well as the locations of cluster prototypes. This algorithm, called multi-scale clustering, is based on scale-space theory by considering that any prominent data structure ought to survive over many scales. The number of clusters as well as the locations of cluster prototypes are found in an objective manner by defining and using lifetime and drift speed clustering criteria. The outcome of this algorithm does not depend on the initial prototype locations that affect the outcome of many clustering algorithms. As an application of this algorithm, it is used to enhance the Hough transform technique. 相似文献
37.
Eiji Akiba 《产业用纺织品》2008,26(5):26-28
SROPE技术是用加入第三组分嵌段聚合物的方法使大剂量的功能性油剂混入热塑性聚合物中,制成具有油剂缓慢析出性能的母粒,可赋予聚合物一定的功能性。SROPE技术对于几乎所有的模压和熔融纺丝工艺都有相当广泛的通用性。 相似文献
38.
Junichi Karasawa Taku Aoyama Takeshi Kijima Eiji Natori Tatsuya Shimoda 《Integrated ferroelectrics》2013,141(1):137-145
A high-pressure annealing was applied to a post-annealing process for sol-gel derived PZT thin films. The squareness of D-E hysteresis curves changes depending on both total pressure and oxygen concentration. Moreover, the change follows the product of the total pressure and the oxygen concentration, which correspond to oxygen partial pressure PO2. Where the PO2 is higher than 0.03 MPa, few of the squareness of the hysteresis curve are excellent. The squareness of the hysteresis curves dramatically improve as the PO2 decreases. Where the PO2 is lower than 0.01 MPa, the squareness deteriorates slightly. These changes in the D-E hysteresis curves are thought to be explained by the generation of lead and oxygen vacancies as a function of the PO2. 相似文献
39.
As a model-based reinforcement learning technique, linearly solvable Markov decision process (LMDP) gives an efficient way to find an optimal policy by making the Bellman equation linear under some assumptions. Since LMDP is regarded as model-based reinforcement learning, the performance of LMDP is sensitive to the accuracy of the environmental model. To overcome the problem of the sensitivity, linearly solvable Markov game (LMG) has been proposed, which is an extension of LMDP based on the game theory. This paper investigates the robustness of LMDP- and LMG-based controllers against modeling errors in both discrete and continuous state-action problems. When there is a discrepancy between the model used for building the control policy and dynamics of the tested environment, the LMG-based control policy maintained good performance while that of the LMDP-based control policy deteriorated drastically. Experimental results support the usefulness of LMG framework when acquiring an accurate model of the environment is difficult. 相似文献
40.
Md Tasyrif Abdul Rahman Nobuyuki KawaharaKazuya Tsuboi Eiji Tomita 《International Journal of Hydrogen Energy》2014
In this work, spark-induced breakdown spectroscopy (SIBS) was employed to investigate the mixing process of a hydrogen jet in a constant-volume vessel. The local fuel concentration of the hydrogen jet was measured at several locations, using a SIBS sensor. A high-speed camera was used to visualize spark discharge fluctuations, and hydrogen jet concentration measurements were conducted simultaneously. Spectrally resolved atomic emissions from the plasma generated by the spark plug were examined to determine the local equivalence ratio. Direct visualization of the spark discharge provided useful information about the influence of spark discharge characteristics related to the spark timing. Using the developed SIBS sensor, atomic emission spectra were obtained from hydrogen Hα at 656 nm and nitrogen N (I) at 501 nm. Comparison of the intensity peaks of atomic emissions from hydrogen and nitrogen allows the local hydrogen concentration in a measured volume to be determined, and hence also the local equivalence ratio. The measurement results demonstrate the local variation in the equivalence ratio throughout the jet and along its axis. From the results, the spatial structure of the hydrogen jet affects the hydrogen/nitrogen mixing and could be clarified with SIBS technique when the spark is discharged. 相似文献