全文获取类型
收费全文 | 1504篇 |
免费 | 100篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 18篇 |
综合类 | 1篇 |
化学工业 | 540篇 |
金属工艺 | 48篇 |
机械仪表 | 32篇 |
建筑科学 | 47篇 |
矿业工程 | 6篇 |
能源动力 | 42篇 |
轻工业 | 326篇 |
水利工程 | 2篇 |
石油天然气 | 4篇 |
武器工业 | 1篇 |
无线电 | 70篇 |
一般工业技术 | 262篇 |
冶金工业 | 22篇 |
原子能技术 | 10篇 |
自动化技术 | 179篇 |
出版年
2024年 | 3篇 |
2023年 | 11篇 |
2022年 | 69篇 |
2021年 | 95篇 |
2020年 | 40篇 |
2019年 | 50篇 |
2018年 | 73篇 |
2017年 | 79篇 |
2016年 | 79篇 |
2015年 | 66篇 |
2014年 | 80篇 |
2013年 | 129篇 |
2012年 | 101篇 |
2011年 | 98篇 |
2010年 | 73篇 |
2009年 | 72篇 |
2008年 | 60篇 |
2007年 | 57篇 |
2006年 | 39篇 |
2005年 | 34篇 |
2004年 | 26篇 |
2003年 | 22篇 |
2002年 | 28篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 14篇 |
1998年 | 11篇 |
1997年 | 14篇 |
1996年 | 19篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 11篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 2篇 |
排序方式: 共有1610条查询结果,搜索用时 0 毫秒
81.
The impact of liberalisation of the electricity market on the hard coal mining sector in Poland 总被引:1,自引:0,他引:1
The liberalisation of the electricity market changed the conditions of operation not only for the power industry, but also for related sectors. One of the particularly sensitive industries in Poland is coal mining, which is the result of coal-based structure of electricity generation. As it is more difficult, in the liberalised market, to burden consumers with all the costs, electricity producers are eager to transfer the risk of operation to the suppliers. That increases uncertainty about the future of the hard coal industry. The aim of this paper was to quantitatively estimate the impact that liberalisation of the electricity markets may have on the coal mining sector in Poland. First of all, the possible areas of that impact were identified. Then the model, which involved detailed relations in the impact areas identified, was developed and employed to evaluate the performance of the mining sector. The comparison of scenarios of a monopolistic electricity sector with a liberalised one enabled an estimation of the scale of the impact on the mining sector to be made. The results showed that liberalisation causes decreased coal consumption and decreased operating profits in coal companies. However, some savings in electricity costs are possible for coal producers. 相似文献
82.
X-ray Photoelectron Spectroscopy (XPS) was used to study the influence of low energy Ar+ ion bombardment, electron bombardment and Pt deposition on the SrTiO3 (STO) single crystal electronic structure. Atomic composition changes were found and attributed to chemical reconstruction of the STO surface. A clear correlation between the presence of conducting, low Ti oxidation states in valence band and core level changes was detected. A strong effect caused by electron irradiation was ascribed to the electroreduction process. The influence of lanthanum doping on surface instability of STO was also discussed. The La doped sample (STO: 3,75% La) was found to be modified upon Pt metal deposition to a higher degree than pure STO crystal. 相似文献
83.
Frydrychowski AF Gumiński W Rojewski M Kaczmarek J Juzwa W 《IEEE transactions on bio-medical engineering》2002,49(8):887-904
This paper presents technical foundations for a new technique of near-infrared transillumination-backscattering sounding, which is designed to enable noninvasive detection and monitoring of changes in the width of the subarachnoid space (SAS) and magnitude of cerebrovascular pulsation in humans. The key novelty of the technique is elimination of influence of blood flow in the scalp on the signals received from two infrared sensors-proximal and distal. A dedicated digital algorithm is used to estimate on line the ratio of the powers of received signals, referred to as two-sensor distal-to-proximal received power quotient, TQ (t). The propagation duct for NIR radiation reaching the distal sensor is the SAS filled with translucent cerebrospinal fluid. Information on slow fluctuations of the average width of the SAS is contained in the slow-variable part of the TQ (t), called the subcardiac component, and in TQ itself. Variations in frequency and magnitude of faster oscillations of the width of that space around the baseline value, dependent on cerebrovascular pulsation, are reflected in instantaneous frequency and envelope of the fast-variable component. Frequency and magnitude of the cerebrovascular pulsation depend on the action of the heart, so this fast-variable component is referred to as the cardiac component. 相似文献
84.
85.
The biological importance and practical significance of phosphate esters and their analogues have been the major driving forces for research in various areas of synthetic organic phosphorus chemistry. In this Account, the authors' studies on the development of a comprehensive H-phosphonate methodology and the underlying chemistry for the preparation of biologically important phosphate esters and their analogues are briefly discussed. 相似文献
86.
Effects of the abdominal belt on muscle-generated spinal stability and L4/L5 joint compression force
The goals of this study were (1) to determine the effects of abdominal belts on muscle-generated active lumbar spine stability, (2) to determine their effect on the subsequent joint compression force at L4/L5 and (3) to determine whether the effective stability of the spine could be predicted by the active spine stability and belt condition. Electromyographic (EMG) and trunk stiffness data from a previously reported experiment in which 10 subjects performed quick-release tasks (perturbation) with and without an abdominal belt were used as inputs to biomechanical models to estimate the active spine stability and effective stability of the spine, respectively. The subjects exerted isometric trunk flexion, extension and lateral bending trials at 0 and 80% of maximum intra-abdominal pressure when the resisted force was suddenly released. Wearing an abdominal belt had no significant effect on either the muscle-generated lumbar spine stability or the L4/L5 joint compression force in any direction. The effective stability of the spine was adequately predicted by the active spine stability and the effect of the belt, which accounted for approximately 34% of the effective spine stability. The study demonstrated that the abdominal belt contributed to the passive stability of the lumbar spine and did not change the active stability for tests performed within the same experimental session. 相似文献
87.
L. Jacak J. Krasnyj D. Jacak R. Gonczarek M. Krzyżosiak P. Machnikowski 《Open Systems & Information Dynamics》2005,12(2):133-141
We define the qubit as a pair of singlet and triplet states of two electrons in a He-type quantum dot (QD) placed in a diluted magnetic semiconductor (DMS) medium. The molecular field is here essential as it removes the degeneracy of the triplet state and strongly enhances the Zeeman splitting. Methods of qubit rotation as well as two-qubit operations are suggested. The system of a QD in a DMS is described in a way which allows an analysis of the decoherence due to spin waves in the DMS subsystem.on leave from Institute of Physics, Odessa UniversityPresented at the 36th Symposium on Mathematical Physics, “Open Systems & Quantum Information”, Toruń, Poland, June 9–12, 2004. 相似文献
88.
G Jacek C Kazimierz R Wojciech H Jolanta K Czes?aw 《Canadian Metallurgical Quarterly》1998,66(5-6):304-311
A group of 37 patients--20 (54%) men and 17 (46%) women--aged 2-65, mean 31.6 years, was treated between 1978 and 1995 for different kinds of primary mediastinal germ cell tumours. In 14 (37.8%) of them a mature solid teratoma was diagnosed, in 13 (35.1%)--dermoid cyst, in 5 (13.5%)--malignant teratoma, in 1 (2.7%)--immature teratoma, in 4 (10.8%)--seminoma. Mediastinal tumour was removed completely in 30 (81.1%) patients, partially in 7 (18.9%). Out of 37 patients, 3 (8.1%) died during postoperative time. Out of 26 patients discharged after surgical removal of mature teratomas, all are alive and have been followed-up for 10 years (17 patients) or 5 years (6 patients). Out of 8 discharged after surgical removal of malignant neoplasm, 3 are alive and all of them had primary mediastinal seminoma. One of them has survived 17 years after complete resection, and two patients--7.5 years and 2 years after partial resection and radiotherapy. Mean survival time is 4 years and 2 months for all patients with malignant neoplasm. 相似文献
89.
Jachner Jacek Agarwal Vinod K. 《IEEE transactions on pattern analysis and machine intelligence》1984,(4):432-437
The occurrence of a data flow anomaly is often an indication of the existence of a programming error. The detection of such anomalies can be used for detecting errors and to upgrade software quality. This paper introduces a new, efficient algorithm capable of detecting anomalous data flow patterns in a program represented by a graph. The algorithm based on static analysis scans the paths entering and leaving each node of the graph to reveal anomalous data action combinations. An algorithm implementing this type of approach was proposed by Fosdick and Osterweil [2]. Our approach presents a general framework which not only fillls a gap in the previous algorithm, but also provides time and space improvements. 相似文献
90.
Results of calculations are presented, which are concerned with applications of the heuristic linear reinforcement systems to the control of pebble-bed HTRs with the OTTO-loading scheme. Control results of three types of systems applications are presented and discussed. The systems were found to be satisfactory for control of the complex physical plants. 相似文献