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   1859篇
  免费   107篇
  国内免费   3篇
电工技术   14篇
综合类   1篇
化学工业   401篇
金属工艺   44篇
机械仪表   51篇
建筑科学   49篇
矿业工程   3篇
能源动力   83篇
轻工业   176篇
水利工程   11篇
石油天然气   19篇
无线电   178篇
一般工业技术   299篇
冶金工业   353篇
原子能技术   34篇
自动化技术   253篇
  2024年   8篇
  2023年   18篇
  2022年   25篇
  2021年   85篇
  2020年   62篇
  2019年   63篇
  2018年   58篇
  2017年   61篇
  2016年   62篇
  2015年   45篇
  2014年   50篇
  2013年   95篇
  2012年   81篇
  2011年   94篇
  2010年   66篇
  2009年   74篇
  2008年   72篇
  2007年   65篇
  2006年   53篇
  2005年   62篇
  2004年   43篇
  2003年   22篇
  2002年   25篇
  2001年   26篇
  2000年   41篇
  1999年   33篇
  1998年   105篇
  1997年   77篇
  1996年   49篇
  1995年   36篇
  1994年   25篇
  1993年   36篇
  1992年   14篇
  1991年   18篇
  1990年   12篇
  1988年   16篇
  1987年   15篇
  1986年   9篇
  1985年   17篇
  1983年   12篇
  1982年   8篇
  1981年   12篇
  1980年   8篇
  1979年   9篇
  1978年   14篇
  1977年   15篇
  1976年   17篇
  1973年   6篇
  1972年   6篇
  1969年   6篇
排序方式: 共有1969条查询结果,搜索用时 546 毫秒
1.
The present study reports for the first time the performance of silver phosphate (Ag3PO4) microcrystals as photocatalyst (degradation of Rodamine B-RhB) and antifungal agent (against Candida albicansC. albicans) under visible-light irradiation (455 nm). Ag3PO4 microcrystals were synthesized by a simple co-precipitation (CP) method at room temperature. The structural and electronic properties of the as-synthetized Ag3PO4 have been investigated before and after 4 cycles of RhB degradation under visible light using X-ray diffraction (XRD), micro-Raman spectroscopy, UV–Vis spectrophotometer and field emission scanning electron microscopy (FE-SEM) images. The antifungal activity was analyzed in planktonic cells and 48h-biofilm of C. albicans by colony forming units (CFU) counting, confocal laser and FE-SE microscopies. Statistical analysis was carried out using SPSS software. Morphological and structural modifications of Ag3PO4 were observed upon recycling. After 4 recycles, the material maintained its photodegradation property; an eightfold increase in the efficiency of Ag3PO4 was observed in planktonic cells and a two fold increase in biofilm when irradiated under visible light. Thus, higher antifungal effectiveness against C. albicans was obtained when associated with visible-light irradiation.  相似文献   
2.
Alcohol-free beer with isotonic properties is getting more popular and its production can be carried out by different production strategies; however, interrupted fermentation is still a challenge. Therefore, the objective of this study was to develop a low-alcohol isotonic beer (<0.5% v/v) by interrupted fermentation. Moreover, the major objective is to compare the developed product to commercial beverages (sports drinks, ‘Pilsen' regular beer, alcohol-free beers and low-alcohol isotonic beer). The beverages were evaluated based on pH, alcohol content (% v/v), total titratable acidity (mEq L−1), osmolality (mOsmol kg−1), bitterness International Bitterness Units, colour European Brewery Convention, total phenolic compounds (mg L−1 gallic acid), reducing and total sugars (%) and Na and K contents (mg L−1). The developed low-alcohol isotonic beer presented characteristics similar to sports drinks, with the advantage of being richer in phenolic compounds and suitable osmolality. Despite salts were added in its formulation, the grades attributed to all beers employed in the sensory evaluation, as well as the purchase intention did not present significant differences.  相似文献   
3.
Debittered trub (brewing waste) is an important source of protein source (70.26%). Trub and whey protein were used for 5% protein enrichment of ice cream frozen by liquid nitrogen. Three formulations were elaborated: ice cream standard (ICS), ice cream with whey protein (ICW) and ice cream with trub (ICT). Chemical composition, rheological properties, texture, overrun, melting rate, scanning electron microscopy and a sensorial test were performed. Results showed that ICT presented a higher viscosity, obtained on the upward curve up to 6.76 Pa s−1, consistency index (22.96 (Pa s−1)n), hysteresis area (140.40 mPa s−1) and hardness (31113.33 g) but a lower melting rate (0.38 g min−1), overrun (13.92%) and sensorial acceptability than the other formulations. The addition of trub debittered for protein enrichment improved ice cream properties and demonstrated that it could be used as a food ingredient.  相似文献   
4.
Personal and Ubiquitous Computing - This article presents a study concerning the evaluation of a smart home control system for elderly people with a sample of 10 users in a city in the interior of...  相似文献   
5.
6.
7.
The LHC insertions will be equipped with individually powered MQM superconducting quadrupoles, produced in three versions with magnetic lengths of 2.4 m, 3.4 m, and 4.8 m. The quadrupoles feature a 56 mm aperture coil, designed on the basis of an 8.8 mm wide Rutherford-type NbTi cable for a nominal gradient of 200 T/m at 1.9 K and 5390 A. A total of 96 quadrupoles are in production in Tesla Engineering, UK. In this report we describe the construction of the pre-series MQM quadrupoles and present the results of the qualification tests.  相似文献   
8.
9.
A new system based on the harnessing of solar and wind power is presented for heat dissipation in air conditioning facilities. The innovation offered by the new system is the integration of two well-known subsystems: a cooling tower and a solar chimney which increases the air flow without the use of electric power. The system is described and presented together with a model for its study. The field data acquired from the prototype built in southern Spain establishes the actual potential of the system, which provides a new approach to a sustainable technological development.  相似文献   
10.
The extinction coefficient ? at 2.9 μm for OH in fluoride glasses is measured by determining the amount of HF evolved during heating of the glass under steam and the corresponding intensity of the OH absorption band. This coefficient is respectively equal to 31 litre mole?1 cm?1 for BTYbZ glass (15 BaF2 - 29 ThF4 - 28 YbF3 - 28 ZnF2) and 19.5 litre mole?1 cm?1 for BALLA glass (34 BaF2 - 57 ZrF4 - 4 AlF3 - 5 LaF3).  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