首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   255篇
  免费   13篇
电工技术   2篇
化学工业   57篇
金属工艺   4篇
机械仪表   17篇
建筑科学   10篇
矿业工程   2篇
能源动力   16篇
轻工业   37篇
水利工程   3篇
石油天然气   6篇
无线电   11篇
一般工业技术   37篇
冶金工业   41篇
原子能技术   1篇
自动化技术   24篇
  2023年   1篇
  2022年   9篇
  2021年   9篇
  2020年   12篇
  2019年   18篇
  2018年   19篇
  2017年   18篇
  2016年   20篇
  2015年   7篇
  2014年   12篇
  2013年   24篇
  2012年   15篇
  2011年   15篇
  2010年   13篇
  2009年   15篇
  2008年   11篇
  2007年   6篇
  2006年   4篇
  2005年   3篇
  2004年   6篇
  2003年   7篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1998年   3篇
  1997年   3篇
  1996年   5篇
  1995年   1篇
  1994年   3篇
  1993年   2篇
  1991年   1篇
  1989年   1篇
  1987年   1篇
排序方式: 共有268条查询结果,搜索用时 0 毫秒
1.
Zirconia is a dental material that shows excellent biocompatibility and high strength in clinical applications. This study aims to evaluate the effects of ultrafast laser applications. The surface nanostructures were classified into three groups. Group 1 was generated using the burst mode, with three different distances between dots: 52 µm (Group 1a), 104 µm (Group 1b), and 156 µm (Group 1c). Group 2 was processed using the scanning mode configuration, with a set of parallel lines. Group 3 was also processed using this scanning configuration creating a set of square-shaped patterning. Group 4 was the control group. After the surface treatments, a pair of zirconia specimens was bonded end to end with resin cement. Flexural bond strength (FBS) test was applied in a universal test machine. Multiple comparisons were performed using a one-way analysis of variance and the Tukey's HSD test. All the samples that were treated with the laser showed higher FBS values than the untreated surface. Using the burst mode, preformed circular-shaped surface on an angle of 900 at 52 µm distance (Group 1a) showed the highest FBS values among all groups (p < .05). Groups 2 and 3 had significantly higher values than 1b and 1c.  相似文献   
2.
Estimation of Peak Flood Discharges at Ungauged Sites Across Turkey   总被引:1,自引:1,他引:0  
The reliable forecasting of the peak flood discharge at river basins is a common problem, and it becomes more complicated when there is inadequate recorded data. The statistical methods commonly used for the estimation of peak flood discharges are generally considered to be inadequate because of the complexity of this problem. Recently, genetic programming (GP) which is a branch of soft computing methods has attracted the attention of the hydrologists. In this study, gene-expression programming (GEP) and linear genetic programming (LGP), which are extensions to GP, in addition to logistic regression (LR) were employed in order to forecast peak flood discharges. The study covered 543 ungauged sites across Turkey. Drainage area, elevation, latitude, longitude, and return period were used as the inputs while the peak flood discharge was the output. Model comparison results revealed that GEP predicted the peak flood discharges with R 2?=?57.4?% correlation, LGP with 56?% and LR model with 42.3?%, respectively. The peak flood discharges in all river basins can now be determined using the single equation provided by the GEP model.  相似文献   
3.
Traditional genetic programming (GP) randomly combines subtrees by applying crossover. There is a growing interest in methods that can control such recombination operations in order to achieve faster convergence. In this paper, a new approach is presented for guiding the recombination process for genetic programming. The method is based on extracting the global information of the promising solutions that appear during the genetic search. The aim is to use this information to control the crossover operation afterwards. A separate control module is used to process the collected information. This module guides the search process by sending feedback to the genetic engine about the consequences of possible recombination alternatives.  相似文献   
4.
Metallurgical and Materials Transactions B - A mathematical model has been developed to predict the decarburization rate within individual droplets in the emulsion zone. All the chronological...  相似文献   
5.
Photoluminescent pigments could be successfully applied on the wall tiles, floor tiles and porcelain tiles as well as glass substrates (glass mosaics, borders, and cutted glass with various designs). For this applications, these products can be used for different purposes. In this study, these pigments are applied on the ceramic tiles and glass mosaics/tiles with traditional ceramic production line. These products are intentended to provide guidance in the event of a power failure. With this study also aimed to prevent potential accidents and injury during evacuation of building.  相似文献   
6.
7.
In this study, geochemical behavior of elements is investigated in 25 coal samples collected at 10 locations of ?ahinli coaliferous units at southeast of Ayd?n, Turkey. In all the samples, X-ray powder diffraction and inductively coupled plasma mass spectrometry analyses were performed and element and mineral compositions were determined. Total organic carbon (TOC) values of coals are between 14.6 and 37.7 wt% with average of 28.5 wt%. Samples are composed of quartz, calcite, feldspar, dolomite, mica, gypsum, and salt minerals which are accompanied by illite-, kaolinite-, and smectite-type clay minerals. Comparison of average element contents of world coals and studied samples yields that K > Fe > As > U > Cs > Y > Er > Al > Th > Rb > Yb > W > Tb > Dy > Lu > Ce > Sm > La > Ho > Si > Nd > Gd > Tm > Eu > Nb > Pr > Pb > Sn > Ni > Cu > Ga > Ta > Sb > Zr > Cd > V > Zn > Co > Mo > P > Hf > Ba are found to be enriched, while Mn > Be > Ca > Sr > Bi > Mg are found to be depleted. Statistically elements are correlated with TOC.  相似文献   
8.
9.
10.
Neutron-induced cross-sections for the stable isotopes 180,182,183,184,186W in the energy region up to 20 MeV have been calculated. Calculations were made with the codes CEM03.01 and ALICE/ASH, using the following models: the Dubna version of the intranuclear cascade model for the cascade stage of interaction; the hybrid, the geometry dependent hybrid and the exciton model for the pre-equilibrium component; the Hauser–Feshbach and the Weisskopf–Ewing statistical models for the equilibrium component. Effects of some important model parameters such as level density parameter and pairing correction were investigated. Calculated cross-sections were compared with available experimental data in the literature and with ENDF/B-VI T = 300 K and JENDL-3.3 T = 300 K evaluated data libraries.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号