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91.
Hocheol Song Seokheung Chang Kwinam Park Ho-chul Shin Jin-won Park Eung-soo Choi Wan-wook Huh 《Canadian Metallurgical Quarterly》2005,131(2):190-195
Urea and NH4HCO3 were used to control the emission of NO and SO2 from the combustion of coke at high-temperature and low oxygen concentration. Urea and NH4HCO3 could control NO emission only under 1100°C. Their effects disappeared above 1100°C even though the increase of urea and NH4HCO3 content from 10?to?50?wt?%. However, they showed good desulfurization effect on the emission of SO2 at all combustion temperatures and their effects showed remarkable results even at 1500°C. Only 10?wt?% of urea or NH4HCO3 could control the emission of SO2 effectively at 1400 and 1500°C. This effect was caused by ?NH and ?NH2 from the thermal decomposition of reducing agents at high temperature. Low O2 concentration showed little effect on the removal of SO2. Ammonia slip from the thermal decomposition of reducing chemical was not a considerable level. 相似文献
92.
By combining a magnetostrictive material with a polymer or a metal, the magnetostrictive composites can have a reasonably large magnetostriction response for various sensor and actuator applications. In this paper, a relatively simple model for studying the magnetostrictively induced deformation behavior of magnetostrictive composites is presented. For illustrative purposes, we calculate the magnetostriction responses of composites containing Terfenol-D and nickel. Through numerical calculation, we have obtained the macroscopic longitudinal strains parallel to the applied magnetic field for Terfenol-D/glass composite and both longitudinal and transverse strains for the nickel/epoxy composite. Comparison with experimental data for both material systems shows our model is applicable up to very high volume fraction of magnetostrictive inclusions. 相似文献
93.
Phase evolution, densification, and dielectric properties of MgTi2O5 dielectric ceramic, sintered with lithium borosilicate (LBS) glass, were studied. Reaction between LBS glass and MgTi2O5 was significant in forming secondary phases such as TiO2 and (Mg,Ti)2(BO3)O. The glass addition was not necessarily deleterious to the dielectric properties due to the formation of TiO2: permittivity increased and temperature coefficient of resonance frequency could be tuned to zero with the addition of LBS glass, although the inevitable glass-induced decrease of quality factor was not retarded by the formation of TiO2. The sintered specimen with 10 wt% LBS fired at 950 °C for 2 h showed permittivity of 19.3, quality factor of 6800 GHz, and τf of −16 ppm/°C. 相似文献
94.
J. H. Song I. K. Park Y. S. Shin J. H. Kim S. W. Hong B. T. Min H. D. Kim 《Nuclear Engineering and Design》2003,222(1):1051-15
This paper discusses the results of steam explosion experiments using reactor material carried out under “Test for Real cOrium Interaction with water (TROI)” program. About 4–9 kg of corium melt jet is delivered into a sub-cooled water pool at atmospheric pressure. Spontaneous steam explosions are observed in four tests among six tests. The dynamic pressure, dynamic load, and morphology of debris clearly indicate the cases with steam explosion. The initial conditions and results of the experiments are discussed. 相似文献
95.
In IEEE 802.12 network, a repeater arbitrates among transmission requests on a round robin basis. A node can transmit a packet only when it is granted by the repeater. Recently, the IEEE 802.12 Committee approved a burst mode in which a node can transmit multiple packets per grant. In burst mode a bandwidth, or the number of packets per grant should be allocated taking into account the timing constraints of real-time messages. This paper proposes bandwidth allocation algorithms based on the burst mode to guarantee the deadlines of periodic real-time messages. Once the bandwidth of each node is derived from the lengths and deadlines of periodic messages, a node is allowed to transmit packets up to the allocated bandwidth per grant. Experimental results show that the proposed algorithms providemuch higher guarantee ratio and graceful degradation for heavy network load, compared with the existing approaches. 相似文献
96.
Haining Wang Danlu Zhang Shin K.G. 《Dependable and Secure Computing, IEEE Transactions on》2004,1(4):193-208
This paper presents a simple and robust mechanism, called change-point monitoring (CPM), to detect denial of service (DoS) attacks. The core of CPM is based on the inherent network protocol behavior and is an instance of the sequential change point detection. To make the detection mechanism insensitive to sites and traffic patterns, a nonparametric cumulative sum (CUSUM) method is applied, thus making the detection mechanism robust, more generally applicable, and its deployment much easier. CPM does not require per-flow state information and only introduces a few variables to record the protocol behaviors. The statelessness and low computation overhead of CPM make itself immune to any flooding attacks. As a case study, the efficacy of CPM is evaluated by detecting a SYN flooding attack - the most common DoS attack. The evaluation results show that CPM has short detection latency and high detection accuracy 相似文献
97.
98.
D.R. Ryu H.Y. Choi S.W. Kang K.H. Choi H.Y. Lee D.S. Han E.W. Kang S.J. Oh S.K. Shin . 《Hemodialysis international. International Symposium on Home Hemodialysis》2004,8(1):94-94
Clinical manifestation of overt vascular disease may be preceded for years by endothelial dysfunction. Objective: This study was undertaken to evaluate endothelial function in ESRD patients and correlation between endothelial function and clinical and biochemical parameters. Methods: 32 stable ESRD patients (male : female = 16 : 16, average age: 55.2 ± 13.0) on hemodialysis were included. A 10‐MHz ultrasound transducer was used to image the brachial artery. Brachial artery diameter was measured, and reactive hyperemia was induced by inflation to 250 mmHg for 5 min and then deflation of a pneumatic cuff. After release of the cuff, brachial artery diameter was measured. Results: In the entire study population and non‐diabetic group, the %FMD (% flow‐mediated dilatation, % change of brachial artery diameter between before and after cuff inflation) did not show any significant correlation with duration of dialysis, age, hypertension, albumin, CRP, total cholesterol, LDL and HDL cholesterol, and triglyceride. However, the %FMD of diabetic patients was lower than that of non‐diabetics. Among the patients with diabetes, the group of patients with FMD of <5.2% showed significant lower serum albumin and significantly higher ln(CRP) levels compared to the group of patients with FMD ≥5.2%. The %FMD showed significant positive correlation with serum albumin level and significant negative correlation with ln(CRP) in diabetic patients. Conclusion: These findings suggest that endothelial dysfunction, estimated by FMD, was significantly more prominent in diabetic ESRD, especially with low serum albumin and high CRP levels. 相似文献
99.
Man Gyun Na Sun Ho Shin Dong Won Jung Soong Pyung Kim Ji Hwan Jeong Byung Chul Lee 《Nuclear Engineering and Design》2004,232(3):267-300
In this work, a probabilistic neural network (PNN) that has been applied well to the classification problems is used in order to identify the break locations of loss of coolant accidents (LOCA) such as hot-leg, cold-leg and steam generator tubes. Also, a fuzzy neural network (FNN) is designed to estimate the break size. The inputs to PNN and FNN are time-integrated values obtained by integrating measurement signals during a short time interval after reactor scram. An automatic structure constructor for the fuzzy neural network automatically selects the input variables from the time-integrated values of many measured signals, and optimizes the number of rules and its related parameters. It is verified that the proposed algorithm identifies very well the break locations of LOCAs and also, estimate their break size accurately. 相似文献
100.
Young Shin Lee Hyun Soo Kim Young Hwan Kang Sung Hwan Chung Young Jin Choi 《Nuclear Engineering and Design》2004,232(2):123-129
The spent fuel storage and transport cask must withstand various accident conditions such as fire, free drop and puncture in accordance with the requirement of the IAEA and domestic regulations. The spent fuel storage and transport cask should maintain the structural safety not to release radioactive material in any condition. And also the effects of the irradiation should be considered because the spent fuels stored in the cask for a long time and be possible to change the mechanical properties of the cask.In this study, the changed mechanical properties of the cask after irradiation for the 30 years storage periods are assumed and applied to the impact analysis using ABAQUS/Explicit code and seismic analysis using ANSYS code. The stress intensity on each part of the cask is calculated and the effects of irradiation are studied and structural integrity of the package is evaluated. 相似文献