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991.
Dr. Kazuhisa Yanagi Naoki Kobayashi Kazufumi Kasahara 《International Journal of Machine Tools and Manufacture》1995,35(2)
This paper deals with surface waviness assessment by a commercial three-dimensional stylus instrument. To measure macroscopic waviness curve on an engineering surface, it was proposed to use a round stylus tip of relatively large radius. Developed in this paper, is a method to obtain the appropriate stylus tip radius in accordance with the sample surface texture and the corresponding discrete spacing for lattice data sampling. On condition that any two adjacent height data points are well-correlated, the statistical mean height and the overall deviation of the 3-D undulation summit height are also presented for a functional evaluation of waviness curves or envelope surface. 相似文献
992.
Dielectric properties of sintered aluminum nitride 总被引:1,自引:0,他引:1
Shoichi Kume Masaki Yasuoka Naoki Omura Koji Watari 《International Journal of Refractory Metals and Hard Materials》2005,23(4-6):382-385
In the present work, the effects of sintering additives on dielectric loss tangent (tan δ) of AlN ceramics were explored. Different amounts of Y2O3 and Mg3N2 were respectively added as sintering additives to AlN powders, and pressureless-sintering was performed at 1900 °C for 2 h in a nitrogen flow atmosphere. The resulted AlN ceramics became denser due to the addition of Mg3N2, and nearly fully dense sample was obtained with a relative density of 0.998. tan δ decreased with increasing Mg3N2 amount and it was found to depend on the density of the AlN ceramic. The best tan δ value of 3.9 × 10−4 was obtained by adding 1 mol% of Y2O3 and Mg3N2 together. 相似文献
993.
Hua Yang Naoki Wakamiya Masayuki Murata Takanori Iwai Satoru Yamano 《Wireless Networks》2017,23(7):2093-2110
The 5th generation mobile and wireless communication systems are expected to accommodate exploding traffic, increasing number of devices, and heterogeneous applications driven by proliferation of IoT and M2M technologies. However, the centralized mobility management architecture in a current mobile core network would face critical problems such as excessive concentration of load on specific servers and considerable increase in C-plane overhead. To solve the problems we first consider a novel architecture of distributed mobility management in C-plane in the mobile core network, which employs virtualized mobility management entity called ADMMEs (Autonomous Distributed Mobility Management Entity) in this paper. In addition, to assign an appropriate ADMME to a UE in accordance with mobility characteristics of the UE and a management policy, we propose an autonomous and adaptive ADMME selection scheme. We adopt a biologically-inspired algorithm, called attractor selection, to accomplish adaptive selection taking into account multiple objectives. Through simulation experiments, we confirmed our proposal could accomplish more than 63 % performance improvement comparing to the current method from viewpoints of delay, load balancing, and C-plane overhead under a dynamic mobility scenario. 相似文献
994.
Ippei Amamoto Hidekazu Kobayashi Naoto Kitamura Hiromichi Takebe Naoki Mitamura Tatsuya Tsuzuki 《Journal of Nuclear Science and Technology》2016,53(10):1467-1475
The search for an enhanced glass medium to immobilize the sludge at the Fukushima Daiichi Nuclear Power Plant is our main purpose. The iron phosphate glass (IPG) is a potential candidate as we set about assessing it by means of theoretical and experimental investigation. Based on the results of this study, the IPG showed favorable characteristics as a vitrification medium for the sludge. 相似文献
995.
Li Liu Kenji Nishida Kenji Dohi Akiyoshi Nomoto Naoki Soneda Kenta Murakami 《Journal of Nuclear Science and Technology》2016,53(10):1546-1553
Nanometer-sized Cu-enriched solute clusters containing Mn, Ni, and Si atoms are considered as the primary embrittling feature in reactor pressure vessel steels. In order to understand the effects of solute atoms Mn, Ni, and Si on hardening and cluster formation, reactor pressure vessel model alloys FeCu, FeCuSi, FeCuNi, and FeCuNiMn were irradiated at 290 °C in a research reactor. Thermal ageing at 450 °C was also carried out to compare with the results in the neutron irradiation. The addition of Mn resulted in larger hardening and higher cluster number density in both thermal ageing and neutron irradiation. In FeCu0.8NiMn alloy, the size distribution of Cu-enriched clusters formed in 62-h thermal ageing (almost peak hardening) was very similar to that formed in the neutron irradiation, indicating they are on a similar growing stage. But the average Ni and Mn composition in clusters formed in neutron irradiation was higher. A good linear relationship between hardening and the square root of cluster volume fraction for both neutron irradiation and thermal ageing data was found. 相似文献
996.
Abdallah Farrage Naoki Uchiyama 《The International Journal of Advanced Manufacturing Technology》2018,99(5-8):1203-1214
Friction occurring in all mechanical systems, such as computer numerical controlled (CNC) machine tools, is an important issue in achieving the high accurate performance. Friction adversely affects not only motion accuracy of drive axes but also excessively consumes energy. Feed drives of CNC machines normally operate all day and night around the world, and therefore consumed energy reduction is highly expected. The motivation behind this work is to construct a novel friction model that can comprise many unknown friction sources in both low and high velocity regions and enable a friction compensator to precisely describe actual frictional behavior. A sliding mode control (SMC) is designed to verify the effectives of the proposed friction model in a biaxial feed drive system. Experimental results confirm that a combination of SMC and the proposed friction can effectively improve tracking accuracy and further achieve significant reduction of consumed energy compared to combining with the conventional model. Results show that the proposed approach can largely decrease the mean tracking error to less than 5 µm for each axis. The new friction also achieved effective reduction of control variance by 7.62%. Consequently, consumed energy of feed drives was significantly improved by 12.83% compared to using the conventional model. 相似文献
997.
Tomoyoshi Shimobaba Jiantong Weng Takahiro Sakurai Naohisa Okada Takashi Nishitsuji Naoki Takada Atsushi Shiraki Nobuyuki Masuda Tomoyoshi Ito 《Computer Physics Communications》2012,183(5):1124-1138
Diffraction calculations, such as the angular spectrum method and Fresnel diffractions, are used for calculating scalar light propagation. The calculations are used in wide-ranging optics fields: for example, Computer Generated Holograms (CGHs), digital holography, diffractive optical elements, microscopy, image encryption and decryption, three-dimensional analysis for optical devices and so on. However, increasing demands made by large-scale diffraction calculations have rendered the computational power of recent computers insufficient. We have already developed a numerical library for diffraction calculations using a Graphic Processing Unit (GPU), which was named the GWO library. However, this GWO library is not user-friendly, since it is based on C language and was also run only on a GPU. In this paper, we develop a new C++ class library for diffraction and CGH calculations, which is referred to as a CWO++ library, running on a CPU and GPU. We also describe the structure, performance, and usage examples of the CWO++ library.Program summaryProgram title: CWO++Catalogue identifier: AELL_v1_0Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AELL_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 109 809No. of bytes in distributed program, including test data, etc.: 4 181 911Distribution format: tar.gzProgramming language: C++Computer: General computers and general computers with NVIDIA GPUsOperating system: Windows XP, Vista, 7Has the code been vectorized or parallelized?: Yes. 1 core processor used in CPU and many cores in GPU.RAM: 256 M bytesClassification: 18External routines: CImg, FFTWNature of problem: The CWO++ library provides diffraction calculations which are useful for Computer Generated Holograms (CGHs), digital holography, diffractive optical elements, microscopy, image encryption and decryption and three-dimensional analysis for optical devices.Solution method: FFT-based diffraction calculations, computer generated holograms by direct integration.Running time: The sample runs provided take approximately 5 minutes for the C++ version and 5 seconds for the C++ with GPUs version. 相似文献
998.
The method of tracer-encapsulated solid pellet (TESPEL) is now flourishing in various fields. The original purpose to study impurity transport without giving substantial perturbation on the plasma is implemented successfully for years. In addition to this, TESPEL is being intensively applied to study thermal (especially non-local) transport, high energy particles with the use of TESPEL ablation cloud, and spectroscopy from the viewpoint of atomic data. It is now further growing up to the utilization of multiple tracer methods which was not planned at the initial phase of the project. The proof-of-principle experiment using triple tracers has been successfully implemented. This opens a way to compare the Z dependence or mass dependence of impurity transport. In this article, as TESPEL is used in a variety of fields, the TESPEL injection system is summarized together with the method of TESPEL production, TESPEL storage disk, TESPEL guide system, and the differential pumping system. Also, the observation system for TESPEL flight and TESPEL ablation is explained. 相似文献
999.
Keisuke Yoneda Toshiki Iida TaeHyon Kim Ryo Yanase Mohammad Aldibaja Naoki Suganuma 《Artificial Life and Robotics》2018,23(4):474-480
The automated driving is an emerging technology in which a car performs recognition, decision making, and control. The decision-making system consists of route planning and trajectory planning. The route planning optimizes the shortest path to the destination like an automotive navigation system. According to static and dynamic obstacles around the vehicle, the trajectory planning generates lateral and longitudinal profiles for vehicle maneuver to drive the given path. This study is focused on the trajectory planning for vehicle maneuver in urban traffic scenes. This paper proposes a trajectory generation method that extends the existing method to generate more natural behavior with small acceleration and deceleration. This paper introduces an intermediate behavior to gradually switch from the velocity keeping to the distance keeping. The proposed method can generate smooth trajectory with small acceleration/deceleration. Numerical experiments show that the vehicle generates smooth behaviors according to surrounding vehicles. 相似文献
1000.
This paper is concerned with a framework to design self-organizing, self-reconfigurable robotic systems. We focus our attention on the algorithm of a multi-agent system called Swarm Chemistry, proposed by Sayama (Artif Life 15:105–114, 2009). In this model, a number of agents that have non-uniform kinetic properties coalesce into an excellent diversity of spatial structures and/or emergent behaviors, depending on the kinetic parameters provided. However, such bottom-up nature cannot be easily applied to the conventional and top-down design of artifacts. This paper presents a method of designing heterogeneous robotic swarms and finding solutions through a genetic algorithm. Simulation results with a few simple task examples demonstrate that the proposed framework allows us to acquire appropriate sets of kinetic parameters, i.e. recipes, creating swarm structures to perform a given task more effectively and efficiently. Such autonomous robots can be deployed for the purposes like disaster prevention, geographical survey, and subsea exploration. 相似文献