全文获取类型
收费全文 | 609893篇 |
免费 | 6693篇 |
国内免费 | 1045篇 |
专业分类
电工技术 | 11249篇 |
综合类 | 529篇 |
化学工业 | 95218篇 |
金属工艺 | 27860篇 |
机械仪表 | 21050篇 |
建筑科学 | 13421篇 |
矿业工程 | 4644篇 |
能源动力 | 14921篇 |
轻工业 | 46622篇 |
水利工程 | 7559篇 |
石油天然气 | 15406篇 |
武器工业 | 39篇 |
无线电 | 64335篇 |
一般工业技术 | 127598篇 |
冶金工业 | 98700篇 |
原子能技术 | 15010篇 |
自动化技术 | 53470篇 |
出版年
2021年 | 5508篇 |
2019年 | 5289篇 |
2018年 | 13864篇 |
2017年 | 14182篇 |
2016年 | 12687篇 |
2015年 | 6300篇 |
2014年 | 10336篇 |
2013年 | 26215篇 |
2012年 | 17285篇 |
2011年 | 25815篇 |
2010年 | 21538篇 |
2009年 | 22617篇 |
2008年 | 23053篇 |
2007年 | 24042篇 |
2006年 | 16340篇 |
2005年 | 16741篇 |
2004年 | 15286篇 |
2003年 | 14848篇 |
2002年 | 13747篇 |
2001年 | 12913篇 |
2000年 | 12459篇 |
1999年 | 12037篇 |
1998年 | 27683篇 |
1997年 | 20054篇 |
1996年 | 15661篇 |
1995年 | 12034篇 |
1994年 | 10893篇 |
1993年 | 10638篇 |
1992年 | 8350篇 |
1991年 | 8135篇 |
1990年 | 8001篇 |
1989年 | 7769篇 |
1988年 | 7494篇 |
1987年 | 6758篇 |
1986年 | 6542篇 |
1985年 | 7398篇 |
1984年 | 6707篇 |
1983年 | 6443篇 |
1982年 | 5781篇 |
1981年 | 5900篇 |
1980年 | 5635篇 |
1979年 | 5744篇 |
1978年 | 5672篇 |
1977年 | 6185篇 |
1976年 | 7692篇 |
1975年 | 5111篇 |
1974年 | 4905篇 |
1973年 | 4981篇 |
1972年 | 4280篇 |
1971年 | 4038篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
I. I. Nemets Yu. N. Trepalina E. A. Doroganov 《Refractories and Industrial Ceramics》2008,49(3):205-208
Physicotechnical properties are provided for concretes based on mechanically-activated phosphate suspensions previously modified
with magnesium and aluminum hydroxides and silicic acid. The results obtained demonstrate the efficiency of using modifying
additions in order to increase the strength and heat resistance of corundum concretes.
Translated from Novye Ogneupory, No. 5, pp. 32–35, May 2008. 相似文献
992.
K. O. Boltar I. D. Burlakov A. M. Filachev E. A. Klimanov V. P. Ponomarenko V. N. Solyakov V. I. Stafeev 《Optical Memory & Neural Networks》2007,16(4):234-247
The recent researches and technological developments of middle and long wavelength infrared HgCdTe photovoltaic detectors
are presented. Structure, topology, design and performance of HgCdTe photodiodes, silicon readout electronics, Focal Plane
Arrays both staring and time delay and integration types, thermal imagers are discussed. Negative differential conductance,
bistability and high frequency oscillations under background infrared radiation in HgCdTe photodiodes are reported. 相似文献
993.
A method is considered to solve a conditional optimization problem with a linear-fractional objective function over permutations.
The performance of sub algorithms to solve this problem is evaluated. The practical efficiency of the algorithm is analyzed
by conducting numerical experiments.
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 133–146, July–August 2007. 相似文献
994.
Cloning of observables, unlike standard cloning of states, aims at copying the information encoded in the statistics of a
class of observables rather then on quantum states themselves. In such a process the emphasis is on the quantum operation
(evolution plus measurement) necessary to retrieve the original information. We analyze, for qubit systems, the cloning of
a class generated by two noncommuting observables, elucidating the relationship between such a process and joint measurements.
This helps in establishing an optimality criterion for cloning of observables. We see that, even if the cloning machine is
designed to act on the whole class generated by two noncommuting observables, the same optimal performances of a joint measurement
can be attained. Finally, the connection with state dependent cloning is enlightened. 相似文献
995.
V. V. Evgrafov V. V. Pavlovsky V. E. Pavlovsky 《Journal of Computer and Systems Sciences International》2007,46(5):836-841
The problem of synthesizing trajectories, planning and implementing the motion of a mobile robot is investigated. The statement of the problem is motivated by the need for designing an optimal control of robots with two wheels controlled independently. Mobile robots with this kinematic scheme are called robots with “differential drive.” 相似文献
996.
997.
R. Adam Rebeles A. Hermanne S. Takcs F. Trknyi S.F. Kovalev A. Ignatyuk 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2007,260(2):672-684
In the frame of a systematic study of light ion induced threshold reactions on natural tin (Sn) excitation functions for alpha particles induced reactions are presented in a 12–38 MeV energy domain. Using a stacked foil activation method the following radioisotopes were identified: 116Te, 117Te, 118Te, 119Te, 121Te, 123Te, 117Sb, 118Sb, 120Sb, 122Sb, 124Sb, 126Sb, 117Sn, 111In. The experimental cross sections for these isotopes are presented for the first time in this energy range and a direct comparison with values calculated with the ALICE-IPPE code is discussed. Possible use of these data for production of some isotopes relevant in nuclear medicine is suggested. 相似文献
998.
E. P. Velikhov N. N. Ponomarev-Stepnoi V. G. Volkov G. G. Gorodetskii Yu. A. Zverkov O. P. Ivanov S. M. Koltyshev V. D. Muzrukova S. G. Semenov V. E. Stepanov A. V. Chesnokov A. D. Shisha 《Atomic Energy》2007,102(5):375-381
This article is devoted to work done in 2002–2006 as part of the unified project Reabilitatsiya to rehabilitate radiation
hazardous objects and sections of the radioactively contaminated territory of the Russian Science Center Kurchatov Institute.
The main objects of the rehabilitation work were old storage sites built for radioactive wastes on the territory of the Institute
when military and civilian nuclear technologies were under development. The structural features of the storage sites, including
the volumes and characteristics of the wastes stored, are presented. The salient aspects of the disposal sites, taken into
account during the rehabilitation work, are discussed. The organization of the rehabilitation operations and the sequence
in which they are performed, the special features of the technical design solutions used, the technological methods, and ways
for conducting the work are described.
__________
Translated from Atomnaya énergiya, Vol. 102, No. 5, pp. 300–306, May, 2007. 相似文献
999.
A. A. Aliev A. V. Suetina A. V. Elistratov A. D. Davydov A. G. Rakhshtadt 《Metal Science and Heat Treatment》2007,49(1-2):75-77
The effect of tempering temperature on the structure, wear resistance, and corrosive properties of steel 08Kh14AN4MDB is studied.
The results of mechanical and corrosion tests are used for constructing an optimization matrix for determining the optimum
tempering temperature.
__________
Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 29–32, February, 2007. 相似文献
1000.
M. A. Gasanov 《Surface Engineering and Applied Electrochemistry》2007,43(5):398-402
We present the results of electric discharge treatment of zeolites for purifying the waste water from the manufacture of polymers. By application of the thermostimulated relaxation method, it has been revealed that in the zeolites, superficial and volumetric charges accumulate. It is shown that the electric discharge effects considerably enhance the efficiency of the adsorptive purification of waste water. 相似文献