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   233篇
  免费   18篇
  国内免费   2篇
电工技术   1篇
化学工业   52篇
金属工艺   14篇
机械仪表   6篇
建筑科学   17篇
矿业工程   2篇
能源动力   6篇
轻工业   23篇
水利工程   14篇
石油天然气   3篇
武器工业   1篇
无线电   26篇
一般工业技术   34篇
冶金工业   25篇
原子能技术   1篇
自动化技术   28篇
  2022年   8篇
  2021年   5篇
  2020年   6篇
  2019年   9篇
  2018年   16篇
  2017年   12篇
  2016年   10篇
  2015年   6篇
  2014年   9篇
  2013年   19篇
  2012年   13篇
  2011年   6篇
  2010年   5篇
  2009年   11篇
  2008年   9篇
  2007年   12篇
  2006年   7篇
  2005年   8篇
  2004年   8篇
  2003年   7篇
  2002年   2篇
  2001年   6篇
  2000年   5篇
  1999年   5篇
  1998年   15篇
  1997年   10篇
  1996年   4篇
  1995年   1篇
  1994年   2篇
  1991年   2篇
  1990年   2篇
  1985年   1篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1976年   2篇
  1975年   2篇
  1974年   1篇
  1973年   1篇
  1971年   1篇
  1970年   1篇
  1966年   1篇
排序方式: 共有253条查询结果,搜索用时 343 毫秒
71.
72.
A tailor-made thermodynamic database of the Fe-Mn-Al-C system was developed using the CALPHAD approach. The database enables predicting phase equilibria and thereby assessing the resulting microstructures of Fe-Mn-Al-C alloys. Available information on the martensite start (Ms) temperature was reviewed. By employing the Ms property model in the Thermo-Calc software together with the new thermodynamic database and experimental Ms temperatures, a set of model parameters for the Fe-Mn-Al-C system in the Ms model was optimised. Employing the newly evaluated parameters, the calculated Ms temperatures of the alloys in the Fe-Mn-Al-C system were compared with the available measured Ms temperatures. Predictions of Ms temperatures were performed for the alloys, Fe-10, 15 and 20 wt.% Mn-xAl-yC. The predictability of the Ms model can be further validated when new experimental Ms temperatures of the Fe-Mn-Al-C system are available.  相似文献   
73.
本文在建构语境中对最为传统的砖石构成叠砌的因素进行分析,总结各因素对叠砌的表现力的影响,并通过相关实例分析砖石砌块叠砌构筑方式在当代表现的新的特点。  相似文献   
74.
Imaging mass spectrometry (IMS) that utilizes matrix-assisted laser desorption/ionization (MALDI) technology can provide a molecular ex vivo view of resected organs or whole-body sections from an animal, making possible the label-free tracking of both endogenous and exogenous compounds with spatial resolution and molecular specificity. Drug distribution and, for the first time, individual metabolite distributions within whole-body tissue sections can be detected simultaneously at various time points following drug administration. IMS analysis of tissues from 8 mg/kg olanzapine dosed rats revealed temporal distribution of the drug and metabolites that correlate to previous quantitative whole-body autoradiography studies. Whole-body MALDI IMS is further extended to detecting proteins from organs present in a whole-body sagittal tissue section. This technology will significantly help advance the analysis of novel therapeutics and may provide deeper insight into therapeutic and toxicological processes, revealing at the molecular level the cause of efficacy or side effects often associated with drug administration.  相似文献   
75.
A newly developed method for the quantification of folic acid in fortified food is presented. An immunoaffinity-based optical biosensor was used to determine folic acid concentration levels in milk powder, infant formula and cereal samples. Accuracy of the method (88–101%) was demonstrated with the analysis of five reference samples. A collaborative precision study, where ten participants at four different laboratories analysed a set of ten samples, resulted in repeatability relative standard deviations of 2–8% and reproducibility relative standard deviations of 4–10%.  相似文献   
76.
Intuitive and efficient, the random subspace ensemble approach provides an appealing solution to the problem of the vast dimensionality of functional magnetic resonance imaging (fMRI) data for maximal-accuracy brain state decoding. Recently, efforts to generate biologically plausible and interpretable maps of brain regions which contribute information to the ensemble decoding task have been made and two approaches have been introduced: globally multivariate random subsampling and locally multivariate Monte Carlo mapping. Both types of maps reflect voxel-wise decoding accuracies averaged across repeatedly randomly sampled voxel subsets, highlighting voxels which consistently participate in high-classification subsets. We compare the mapping sensitivities of the approaches on realistic simulated data containing both locally and globally multivariate information and demonstrate that utilizing the inherent volumetric nature of fMRI through clustered Monte Carlo mapping yields dramatically improved performances in terms of voxel detection sensitivity and efficiency. These results suggest that, unless a priori information specifically dictates a global search, variants of clustered sampling should be the priority for random subspace brain mapping.  相似文献   
77.
78.
Photo-assisted charging is considered an effective approach to reducing the overpotential in lithium–oxygen (Li–O2) batteries. However, the utilization of photoenergy during the discharge process in a Li–O2 system has been rarely reported, and the functional mechanism of such a process remains unclear. Herein, a novel bifunctional photo-assisted Li–O2 system is established by employing a hierarchical TiO2–Fe2O3 heterojunction, in which the photo-generated electrons and holes play key roles in reducing the overpotential in the discharging and charging processes, respectively. Moreover, the morphology of the discharge product (Li2O2) can be modified via the dense surface electrons of the cathode under illumination, resulting in promoted decomposition kinetics of Li2O2 during the charging progress. Accordingly, the output and input energies of the battery can be tuned by illumination, giving an ultralow overpotential of 0.19 V between the charge and discharge plateaus with excellent cyclic stability (retaining a round-trip efficiency of ≈86% after 100 cycles). The investigation of the bifunctional photo-assisted process presented here provides significant insight into the mechanism of the photo-assisted Li–O2 battery and addresses the overpotential bottleneck in this system.  相似文献   
79.
The cost and quality of food products are issues that concern both the consumer and producer. In this research, the process used for the production of a commercial spread was subjected to a statistical experimental design for the purpose of reducing the cost of production while maintaining or improving the sensory quality. Three factors—the amount of oil added (x 1), the speed of puddling (x 2), and the temperature treatment (A or B; x 3)—were varied according to a full-factorial design at two levels. The experiments were performed over 2 d, and the factorial design was complemented with three replicates for temperature treatments A and B, which were performed on different days. The products were evaluated with both sensory and physicochemical measurements. Special attention was paid to the hardness of the product since it was permissible to reduce it slightly. In contrast, sensory quality aspects of the product including butter-aroma and off-flavor, as well as other quality properties such as spreadability, shine, and meltability, had to be maintained at the present level or improved. Statistical evaluation of the data showed that it was possible to add high amounts of oil (x 1) without impairing the sensory quality of the product and, hence, reduce the cost of production. The hardness of the product was also slightly reduced when using the high level of oil. In maintaining other sensory qualities such as shine and spreadability at the present levels, the choice of temperature treatment (x 3) was important.  相似文献   
80.
ABSTRACT

This paper discusses potential security issues in business process outsourcing environment arising due to lack of cyber legislation. A set of solutions based on existing cyber laws in developed nations is discussed, suggesting the need for implementation of cyber laws in Kenya and other developing nations wishing to take part in the business process outsourcing industry.  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