全文获取类型
收费全文 | 5063篇 |
免费 | 374篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 94篇 |
综合类 | 9篇 |
化学工业 | 1192篇 |
金属工艺 | 293篇 |
机械仪表 | 218篇 |
建筑科学 | 110篇 |
矿业工程 | 75篇 |
能源动力 | 211篇 |
轻工业 | 301篇 |
水利工程 | 60篇 |
石油天然气 | 192篇 |
无线电 | 454篇 |
一般工业技术 | 1198篇 |
冶金工业 | 427篇 |
原子能技术 | 184篇 |
自动化技术 | 431篇 |
出版年
2023年 | 66篇 |
2022年 | 125篇 |
2021年 | 144篇 |
2020年 | 134篇 |
2019年 | 147篇 |
2018年 | 205篇 |
2017年 | 197篇 |
2016年 | 247篇 |
2015年 | 174篇 |
2014年 | 205篇 |
2013年 | 293篇 |
2012年 | 198篇 |
2011年 | 217篇 |
2010年 | 183篇 |
2009年 | 185篇 |
2008年 | 174篇 |
2007年 | 159篇 |
2006年 | 125篇 |
2005年 | 129篇 |
2004年 | 106篇 |
2003年 | 76篇 |
2002年 | 101篇 |
2001年 | 90篇 |
2000年 | 90篇 |
1999年 | 80篇 |
1998年 | 90篇 |
1997年 | 85篇 |
1996年 | 50篇 |
1995年 | 47篇 |
1993年 | 52篇 |
1992年 | 36篇 |
1991年 | 46篇 |
1990年 | 52篇 |
1989年 | 58篇 |
1988年 | 44篇 |
1986年 | 40篇 |
1985年 | 38篇 |
1984年 | 45篇 |
1983年 | 48篇 |
1982年 | 38篇 |
1980年 | 38篇 |
1978年 | 49篇 |
1977年 | 62篇 |
1976年 | 57篇 |
1975年 | 48篇 |
1974年 | 53篇 |
1973年 | 54篇 |
1972年 | 39篇 |
1971年 | 47篇 |
1969年 | 40篇 |
排序方式: 共有5449条查询结果,搜索用时 0 毫秒
41.
I. N. Sorokin T. M. Golovina D. S. Rutman A. D. Popov V. M. Ust'yantsev V. A. Perepelitsyn T. É. Khairov N. V. Latypova N. I. Cherneta M. V. Galkin V. N. Kiselev A. E. Fadeev 《Refractories and Industrial Ceramics》1984,25(5-6):293-296
Conclusions The possibility of obtaining clinker from high-alumina cement by melting a mixture of lime and technical alumina in an electric-arc furnace at the Klyuchevsk Ferroalloy Plant has been shown.The high-alumina cement obtained from fused clinker is significantly better in its physicochemical properties than the cement produced on the basis of the lime-alumina slags from the ferroalloy industry.Translated from Ogneupory, No. 5, pp. 25–27, May, 1984. 相似文献
42.
VNIISV, Tver'. Institute of Chemical Physics, Moscow. Translated from Khimicheskie Volokna, No. 3, pp. 42–43, May–June, 1992. 相似文献
43.
Silhouette-based human action recognition using SAX-Shapes 总被引:1,自引:0,他引:1
Human action recognition is an important problem in Computer Vision. Although most of the existing solutions provide good accuracy results, the methods are often overly complex and computationally expensive, hindering practical applications. In this regard, we introduce the combination of time-series representation for the silhouette and Symbolic Aggregate approXimation (SAX), which we refer to as SAX-Shapes, to address the problem of human action recognition. Given an action sequence, the extracted silhouettes of an actor from every frame are transformed into time series. Each of these time series is then efficiently converted into the symbolic vector: SAX. The set of all these SAX vectors (SAX-Shape) represents the action. We propose a rotation invariant distance function to be used by a random forest algorithm to perform the human action recognition. Requiring only silhouettes of actors, the proposed method is validated on two public datasets. It has an accuracy comparable to the related works and it performs well even in varying rotation. 相似文献
44.
Ghurmallah H. Al‐Ghamdi E. David Sudol Victoria L. Dimonie Mohamed S. El‐Aasser 《应用聚合物科学杂志》2006,101(6):4504-4516
Miniemulsification technology was used to encapsulate TiO2 particles inside a styrene/n‐butyl acrylate copolymer with high loading levels (11 to 70% PVC (pigment volume concentration)). In this approach, a St/BA copolymer dissolved in toluene in the presence of a costabilizer (hexadecane) was mixed with a dispersion of TiO2 particles in toluene and sonified, and then emulsified in an aqueous surfactant solution by sonification. The effect of sonification time on both the dispersibility of the TiO2 particles in the presence of the copolymer and hexadecane and on the encapsulated particle size was investigated. Particle size analysis by dynamic light scattering showed that these composite latexes are quite stable. It was also found that as the TiO2 loading increased from 11 to 43% PVC, the particle size of the TiO2 dispersion decreased while the polymer‐encapsulated TiO2 particle size increased. The effect of surfactant concentration (sodium lauryl sulfate, SLS) on the encapsulated particle size was investigated using four different SLS concentrations in the 11% PVC system. The results showed that as the SLS concentration increased the particle size decreased, as expected. Also it was found that the minimum surfactant concentration that gives stable encapsulated TiO2 particles is above 10 mM SLS. The role of HD in the recipe was studied for an artificial latex containing no TiO2 and one prepared at 11% PVC, in terms of particle size before and after solvent stripping, and its effect on the Tg. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4504–4516, 2006 相似文献
45.
Members of health social networks may be susceptible to privacy leaks by the amount of information they leave behind. The threat to privacy increases when members of these networks reuse their pseudonyms in other social networks. The risk of re‐identifying users from such networks requires quantitative estimates to evaluate its magnitude. The estimates will enable managers and members of health social communities to take corrective measures. We introduce a new re‐identification attack, the social network attack, that takes advantage of the fact that users reuse their pseudonyms. To demonstrate the attack, we establish links between MedHelp and Twitter (two popular social networks) based on matching pseudonyms. We used Bayesian networks to model the re‐identification risk and used stylometric techniques to identify the strength of the links. On the basis of our model 7‐11. 8% of the MedHelp members in the sample population who reused their pseudonyms in Twitter were re‐identifiable compared with 1% who did not. The risk estimates were measured at the 5% risk threshold. Our model was able to re‐identify users with a sensitivity of 41% and specificity of 96%. The potential for re‐identification increases as more data is accumulated from these profiles, which makes the threat of re‐identification more serious. 相似文献
46.
Rebwar Hassan Nadhir Al‐Ansari Ammar A. Ali Salahalddin S. Ali Sven Knutsson 《Lakes & Reservoirs: Research and Management》2017,22(2):179-189
The Dokan Reservoir dam is a concrete cylindrical arch with gravity abutments, located on the Lesser Zab River about 60 km from the city of Sulaimani in north‐eastern Iraq. A bathymetric survey was conducted in November 2014 for a period of 10 days, using an echo sounder of 200‐kHz single beam. The survey results indicated an annual average sediment deposition of 3.8 million m3. Thirty‐two sediment samples were collected from the reservoir bed. The ratio of gravel, sand, silt and clay was 15:14:48:23, respectively. The reservoir bed is covered mainly with silt. The sediments are composed of silty clay (77.6%), silty sandy clay (10%), sandy gravely silty clay (1.2%) and gravely sandy silty clay (1%). 相似文献
47.
V. I. Popov 《Solid Fuel Chemistry》2007,41(4):225-233
A model for pulverized fuel combustion with allowance for the microstate of the fuel is proposed. It was shown that the burning of a fuel particle having a microstructure follows the laws of external (diffusion) and internal (relaxation) kinetics. The influence of the diffusion-relaxation mechanism on the burnout time of a fuel particle with a polymeric microstructure, its stressed state, and the pulverized fuel flame length was analyzed. The ranges of pulverized-fuel combustion parameters in which the flame length is determined by the fuel combustion or the gas jet mixing mechanism were distinguished. 相似文献
48.
Zhaohui Cen Hassan Noura Tri Bagus Susilo Younes Al Younes 《Journal of Intelligent and Robotic Systems》2014,73(1-4):573-588
A robust Fault Diagnosis (FD) scheme for a real quadrotor Unmanned Aerial Vehicle (UAV) is proposed in this paper. Firstly, a novel Adaptive Thau observer (ATO) is developed to estimate the quadrotor system states and build a set of offset residuals to indicate actuators’ faults. Based on these residuals, some rules of Fault Diagnosis (FD) are designed to detect and isolate the faults as well as estimate the fault offset parameters. Secondly, a synthetic robust optimization scheme is presented to improve Fault Estimation (FE) accuracies, three key issues include modeling uncertainties, and magnitude order unbalances as well as noises are addressed. Finally, a typical fault of rotors is simulated and injected into one of four rotors of the quadrotor, and experiments for the FD scheme have been carried out. Unlike former research works on the FD schemes for quadrotors, our proposed FD scheme based on the ATO can not only detect and isolate the failed actuators, but also estimate the fault severities. Regardless of roughness of the real flying data, the FD results still have sufficient FE accuracies. 相似文献
49.
E. F. Kolomeitseva O. N. Popov V. V. Kolomeitsev 《Refractories and Industrial Ceramics》1987,28(3-4):221-225
Conclusions The heat resistance of specimens from different zones of BKCh-33 production parts was investigated by the method of radial thermal flow. Specimens the microstructure of which is distinguished by the minimum quantity of defects, a fine crystalline structure of the products of combined crystallization of baddeleyite and corundum, and uniform distribution of glassy phase have the highest heat resistance, which should be taken into consideration in the production of refractories in industry.Translated from Ogneupory, No. 4, pp. 49–53, April, 1987. 相似文献
50.