全文获取类型
收费全文 | 531篇 |
免费 | 14篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 24篇 |
化学工业 | 168篇 |
金属工艺 | 6篇 |
机械仪表 | 6篇 |
建筑科学 | 8篇 |
能源动力 | 54篇 |
轻工业 | 57篇 |
水利工程 | 2篇 |
无线电 | 26篇 |
一般工业技术 | 107篇 |
冶金工业 | 8篇 |
原子能技术 | 28篇 |
自动化技术 | 55篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 20篇 |
2012年 | 19篇 |
2011年 | 27篇 |
2010年 | 28篇 |
2009年 | 31篇 |
2008年 | 31篇 |
2007年 | 32篇 |
2006年 | 24篇 |
2005年 | 15篇 |
2004年 | 23篇 |
2003年 | 19篇 |
2002年 | 18篇 |
2001年 | 12篇 |
2000年 | 15篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 8篇 |
1985年 | 12篇 |
1984年 | 15篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1969年 | 3篇 |
排序方式: 共有549条查询结果,搜索用时 15 毫秒
1.
Michio Kumagai Kanako Ishikawa Jiao Chunmeng 《Lakes & Reservoirs: Research and Management》2002,7(4):345-348
We have examined two aspects of the dynamics and biogeochemical significance of the physical environment in Lake Biwa. One is the horizontal distribution of cyanobacteria as it relates to the ‘first gyre’ in the north basin of Lake Biwa. We could easily measure the first gyre using a vessel‐mounted acoustic doppler currents profiler. We were able to quantify the dynamics of the horizontal and vertical structure of currents and water temperature of this gyre. The first gyre did not remain at a fixed position; it moved north and south according to the growth of the gyre. This may play a role in the redistribution of cyanobacteria from place to place in the north basin. The second important environmental dynamic we measured was oxygen consumption rates from 1994 to 2000. We found that the minimum oxygen concentration in the hypolimnion has a clear inverse relationship with the apparent oxygen consumption rates in the 80–85 m depth layer. As a reduction in oxygen concentration in the hypolimnion can have a serious impact on benthic organisms, we concluded that the Lake Biwa environment should be monitored carefully and systematically. 相似文献
2.
Inertinite concentrates from three Australian bituminous coals were hydrogenated at various temperatures ranging from 350 to 475 °C in the presence of tetralin without any added catalyst. Both conversion yields and microscopic observations of the benzene-extracted hydrogenation residues have revealed that the hydrogenation of the inertinite macerals becomes significant only > 400 °C, whereas the dissolution-hydrogenation of the accompanying vitrinite macerals occurs mainly between 350 and 400 °C. The major reaction pathway for the inertinite particles in the hydrogenation process appears to be one of initial mild carbonization followed by hydrogenation. A simplified reaction scheme is proposed which describes the reaction pathway involved in the hydrogenation of inertinite. 相似文献
3.
膨胀石墨对各种油类的吸附动力学 总被引:9,自引:1,他引:8
Michio INAGAKI Tomoya NAGATA Taisuke SUWA Masahiro TOYODA 《新型炭材料》2006,21(2):97-102
通过对吸附率(有效吸附系数)Ks和饱和吸附量msat的测量,描述了粘度为0.001 Pa·s~0.850 Pa·s的各种油类在膨胀石墨柱中的吸附动力学,发现吸附率Ks对油类粘度有很强的相关性.吸入膨胀石墨柱中的饱和吸附量msat几乎恒定在50kg/kg,该值略低于由膨胀石墨块直接浸渍在油中测得的吸附容量,这是由于所吸附的油沿膨胀石墨柱高度存在重力梯度. 相似文献
4.
Tsuyoshi Takahashi Masahito Kitou Michio Asai Mitsuyasu Kido Tomio Chiba Junzou Kawakami Yoshiaki Matsui 《Electrical Engineering in Japan》1994,114(2):18-33
Power system control equipment needs higher sensitivity and operational reliability. Advanced voltage control equipment is needed for reducing the frequency of tap changes and improving the characteristics (the relationship between the actual voltage and reference voltage) of the voltage to meet today's power system requirements. However, these objectives are in a trade-off relationship. Studies of voltage control derived from a knowledge base suitable for electric power systems can satisfy these objectives using fuzzy inference. Compared with corresponding conventional equipment, the new equipment improved the deviation of 30 min average voltage of 30 percent. This paper describes the design concept of new voltage control equipment using fuzzy inference. In addition, field test results are described along with rules of fuzzy inference, membership functions, and the deviation of 30 min average voltage through detailed simulation. 相似文献
5.
Design of active vehicle suspension has tradeoffs between three main performance metrics (passenger comfort, suspension deflection
and road holding ability). It has been known that each performance can be achieved by H
∞ controller and they can be gathered by LPV (Linear Parameter Varying) method. However, because the suspension deflection
limit was not explicitly considered, this limit may be exceeded. In this paper, the authors propose a “reference shaping“
based method in order to improve the control performance. In this approach, a “virtual reference” signal is imposed to the
system such that the suspension deflection is kept small. The effectiveness of the approach is examined by numerical simulations.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
6.
In this article, a new control scheme named repetitive control is proposed for a class of nonlinear systems described by x(t) = Ax(t) + Bu(t) + n(x(t)) and y(t) = Cx(t), in which the controlled variables follow periodic reference commands. The stability condition is derived by applying the passivity theorem. We show how to apply the repetitive control scheme to the trajectory control of a manipulator. A simple repetitive control scheme is developed for the trajectory control of a manipulator by using nonlinear compensation and feedbacks of position and velocity signals. Experimental results for a three link manipulator verify that the proposed repetitive control reduces the tracking error to a very low level. 相似文献
7.
Yoshiro Nakamura Akira Watanabe Kunio Mori Kosaku Tamura Michio Inagaki 《Journal of Materials Science》1986,21(12):4485-4488
A binary blend which consists of two incompatible polymers such as poly(vinyl chloride) and polyethylene has been performed through a partial co-crosslinking reaction with peroxide to give a co-crosslinked blend with a uniform dispersion of small polyethylene particles and with an improved mechanical property. The results are obtained through the formation of a co-crosslinked product which acts as a potential solid phase dispersant as well as a well-bonded reinforcing interlayer on polyethylene particles uniformly dispersed in poly(vinyl chloride) matrix. The resulting blends (PVC/PE=10/90 wt) give carbon spherules of 0.5 to 1m diameter through pressure-carbonization at 650° C for 1 h. 相似文献
8.
The dynamic moduli, E′ and E″, and tan δ for nylon–CR and PET–CR composites with unidirectional short fibers were studied as a function of temperature by using a Rheovibron. The temperature dependence of tan δ showed two dispersion peaks for nylon–CR composite. The peak at ?28°C corresponded to the main dispersion of CR and the peak at 100°C to the α-dispersion of nylon 6. For a PET-CR composite, in addition to the individual dispersion of CR and PET, a small and broad peak was observed at about 90°C. The angular dependence of E′ indicated that the short fibers assumed good orientation. The storage modulus for the composites was given by the parallel model as E′ = Vf′Ef + VmE′m., where E′c, E′f and E′m were the storage modulus for the composite, fiber, and matrix and Vf and Vm were the volume fraction of fiber and matrix, respectively. In the transverse direction of fiber, the peak values of tan δ at ?28°C were given by the following equation; tan δc = tan δm ? δVf, where tan δc and tan δm are the loss tangent for the composite and matrix, respectively, and α is coefficient depending on fiber type. The results indicated that a region with strong interaction was formed between fibers and CR matrix. 相似文献
9.
Michio Shibaoka 《Fuel》1982,61(3):265-270
The behaviour of various huminite macerals and submacerals in a hydrogen-donor solvent, tetralin, at high temperature under hydrogen pressure was investigated. Small granular samples of three Victorian brown coals of different lithotype were treated with tetralin in two types of autoclave, at temperatures of 300–380 °C and under pressures of 5 or 10 MPa. The residual materials were investigated microscopically. This tetralin treatment caused huminite macerals and submacerals derived from highly gelified cellular material to become plastic even at temperatures as low as 340 °C, whereas it had no such effect on those derived from ungelified material. This relation between the degree of gelification and the tendency to become plastic during tetralin treatment in an autoclave is very similar to that found for vitrinite macerals and submacerals from bituminous coals. 相似文献
10.