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   1530篇
  免费   89篇
  国内免费   184篇
电工技术   23篇
综合类   84篇
化学工业   235篇
金属工艺   133篇
机械仪表   82篇
建筑科学   57篇
矿业工程   6篇
能源动力   26篇
轻工业   115篇
水利工程   29篇
石油天然气   53篇
无线电   122篇
一般工业技术   613篇
冶金工业   52篇
原子能技术   30篇
自动化技术   143篇
  2024年   27篇
  2023年   92篇
  2022年   130篇
  2021年   109篇
  2020年   38篇
  2019年   23篇
  2018年   18篇
  2017年   23篇
  2016年   19篇
  2015年   23篇
  2014年   24篇
  2013年   28篇
  2012年   181篇
  2011年   222篇
  2010年   51篇
  2009年   32篇
  2008年   113篇
  2007年   96篇
  2006年   93篇
  2005年   77篇
  2004年   61篇
  2003年   34篇
  2002年   27篇
  2001年   36篇
  2000年   25篇
  1999年   44篇
  1998年   22篇
  1997年   31篇
  1996年   24篇
  1995年   26篇
  1994年   13篇
  1993年   7篇
  1992年   10篇
  1991年   7篇
  1990年   4篇
  1989年   4篇
  1987年   3篇
  1985年   2篇
  1983年   1篇
  1982年   2篇
  1980年   1篇
排序方式: 共有1803条查询结果,搜索用时 15 毫秒
91.
92.
l-Introducti0nUptol995,powerplantsdirectlyunderNortheastChinaElectricP0werGroupCorPorati0n(NEPGC)possessed44setsof2O0MWthermalp0wergeneratingunits.Theseunitstake0nthemajorelectricit}generationofthepowernetwork.Most0ftheirb0ilersareHG670/l40typesuperhighpressure,intermediatereheat,singledrumnaturalcirculationpulverized-c0alfiredboilersproducedbyHarbinBoilerWorks,andthemainandauxiliaryequipmentweremadeintheperiodfromthelatel97Ostotheearlyl980s.Owingt0thebackwardnessinequipmenttechnology…  相似文献   
93.
Carbon solubility in MnFe melts (xMn=0083-0706, xFe=0034-0715) was measured experimentally at various temperatures. By thermodynamic derivation and calculation, the relationship between activity coefficient of carbon in infinite dilute solution of manganese in MnC system and temperature was obtained. Using GibbsDuhem relationship, the experimental results of this study, and experimental data obtained by strict thermodynamic derivation and calculation in references, the relationships between other thermodynamic properties (εCC, εCCC, εCFe, εCCFe, and εCFeFe) in MnFeC system and temperature were obtained.  相似文献   
94.
The key to multi-sensor image fusion is the fusion of infrared and visible images. Fusion of infrared and visible images with generative adversarial network(GAN) has great advantages in automatic feature extraction and subjective vision improvement. Due to different principle between infrared and visible imaging, the blur phenomenon of edge and texture is caused in the fusion result of GAN. For this purpose, this paper conducts a novel generative adversarial network with blur suppression. Specif...  相似文献   
95.
This paper aims to provide an efficient and straightforward structural form-finding method for designers to extrapolate component forms during the conceptual stage. The core idea is to optimize the classical method of structural form-finding based on principal stress lines by using parametric tools. The traditional operating process of this method relies excessively on the designer's engineering experience and lacks precision. Meanwhile, the current optimization work for this method is overly complicated for architects, and limitations in component type and final result exist. Therefore, to facilitate an architect's conceptual work, the optimization metrics of the method in this paper are set as simplicity, practicality, freedom, and rapid feedback. For that reason, this paper optimizes the method from three aspects: modeling strategy for continuum structures, classification processing of data by using the k-nearest neighbor algorithm, and topological form-finding process based on stress lines. Eventually, it allows architects to create structural texture with formal aesthetics and modify it in real time on the basis of structural analysis results. This paper also explores a comprehensive application strategy with internal force analysis diagramming to form-finding. The finite element analysis tool Karamba3D verifies the structural performance of the form-finding method. The performance is compared with that of the conventional form, and the comparison results show the practicality and potential of the strategy in this paper.  相似文献   
96.
<正>Last year,China rubber industry had a"perturbed year",it entered 2014 in optimism and steps into 2015 in pessimism.According to the statistics of China Rubber Industry Association on 46 main tire enterprises,obvious deviation showed in the main indicators of tire industry,that is,the output increased  相似文献   
97.
陈其沓 《四川建材》2010,36(2):50-51
作者结合工作经验,就建筑外墙保温技术应用、建筑外墙保温技术的种类、建筑外墙保温节能材料及外墙保温隔热技术等问题进行了探讨,供同行参考借鉴。  相似文献   
98.
Dimethyl phthalate esters (DMPE) can easily be released into the environment from plastic products. As endocrine disruptors, DMPE mimic estrogenic activities in animals and humans. The metabolites of DMPE are suspected to cause even more serious health problems. Among the common sterilization techniques adopted in the study of DMPE degradation, the average loss of the parent DMPE compounds after autoclaving was as high as 21.26%. In contrast, the loss after 0.2 microm filtration was significantly lower at 2.28%. It is suggested that filtration should be used over autoclaving for sterilizing DMPE. The environmental fate of DMPE under sulfate-reducing condition was simulated and studied in microcosm system. It was observed that dimethyl phthalate (DMP), dimethyl isophthalate (DMI) and dimethyl terephthalate (DMT) could not be mineralized over an extended period of 6 months, but with the transformation to the respective monomethyl phthalate and/or phthalic acid. The dominant species of microorganisms utilizing individual DMPE isomer as the sole carbon source were isolated and identified as facultative anaerobe Thauera sp., Xanthobacter sp. and Agrobacterium sp. for DMP, DMI and DMT, respectively. This study illustrates that the detrimental DMPE and their natural metabolites may accumulate in the sulfate-reducing environment. Accordingly, proper surveillance program should be devised to monitor both the parent compounds and degradation intermediates of DMPE in order to protect the aquatic ecosystem and human health.  相似文献   
99.
The two-electron cytoplasmic reductase NAD(P)H:quinone oxidoreductase 1 is expressed in many tissues. NAD(P)H:quinone oxidoreductase 1 is well-known for being highly expressed in most cancers. Therefore, it could be a target for cancer therapy. Because it is a quinone reductase, many bioimaging probes based on quinone structures target NAD(P)H:quinone oxidoreductase 1 to diagnose tumours. Its expression is higher in tumours than in normal tissues, and using target drugs such as β-lapachone to reduce side effects in normal tissues can help. However, the physicochemical properties of β-lapachone limit its application. The problem can be solved by using nanosystems to deliver β-lapachone. This mini-review summarizes quinone-based fluorescent, near-infrared and two-photon fluorescent probes, as well as nanosystems for delivering the NAD(P)H:quinone oxidoreductase 1-activating drug β-lapachone. This review provides valuable information for the future development of probes and nano-delivery systems that target NAD(P)H:quinone oxidoreductase 1.  相似文献   
100.
A novel solid amine sorbent was prepared using KIT-6-type mesoporous silica modified with tetraethylenepentamine (TEPA). Its adsorption behavior toward CO(2) from simulated flue gases is investigated using an adsorption column. The adsorption capacities at temperatures of 303, 313, 333, 343, and 353 K are 2.10, 2.29, 2.58, 2.85, and 2.71 mmol g(-1), respectively. Experimental adsorption isotherms were obtained, and the average isosteric heat of adsorption was 43.8 kJ/mol. The adsorption capacity increases to 3.2 mmol g(-1) when the relative humidity (RH) of the simulated flue gas reaches 37%. The adsorption capacity is inhibited slightly by the presence of SO(2) at concentrations lower than 300 ppm but is not significantly influenced by NO at concentrations up to 400 ppm. The adsorbent is completely regenerated in 10 min at 393 K and a pressure of 5 KPa, with expected consumption energy of about 1.41 MJ kg(-1) CO(2). The adsorption capacity remains almost the same after 10 cycles of adsorption/regeneration with adsorption conditions of 10 vol % CO(2), 100 ppm SO(2), 200 ppm NO, 100% relative humidity, and a temperature of 393 K. The solid amine sorbent, KIT-6(TEPA), performs excellently for CO(2) capture and its separation from flue gas.  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