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   1089篇
  免费   120篇
  国内免费   1篇
电工技术   8篇
综合类   2篇
化学工业   399篇
金属工艺   9篇
机械仪表   44篇
建筑科学   44篇
矿业工程   1篇
能源动力   36篇
轻工业   332篇
水利工程   15篇
石油天然气   8篇
无线电   28篇
一般工业技术   144篇
冶金工业   59篇
原子能技术   1篇
自动化技术   80篇
  2024年   5篇
  2023年   22篇
  2022年   55篇
  2021年   101篇
  2020年   53篇
  2019年   65篇
  2018年   65篇
  2017年   67篇
  2016年   54篇
  2015年   39篇
  2014年   72篇
  2013年   69篇
  2012年   82篇
  2011年   93篇
  2010年   68篇
  2009年   53篇
  2008年   42篇
  2007年   43篇
  2006年   31篇
  2005年   19篇
  2004年   19篇
  2003年   16篇
  2002年   11篇
  2001年   6篇
  2000年   5篇
  1999年   6篇
  1998年   20篇
  1997年   10篇
  1996年   6篇
  1995年   1篇
  1994年   1篇
  1993年   3篇
  1992年   1篇
  1990年   1篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1977年   1篇
  1976年   2篇
排序方式: 共有1210条查询结果,搜索用时 31 毫秒
21.
Machine Learning - Machine Learning studies often involve a series of computational experiments in which the predictive performance of multiple models are compared across one or more datasets. The...  相似文献   
22.
Reactive oxygen and nitrogen species (RONS) are essential for normal physiological processes and play important roles in cell signaling, immunity, and tissue homeostasis. However, excess radical species are implicated in the development and augmented pathogenesis of various diseases. Several antioxidants may restore the chemical balance, but their use is limited by disappointing results of clinical trials. Nanoparticles are an attractive therapeutic alternative because they can change the biodistribution profile of antioxidants, and possess intrinsic ability to scavenge RONS. Herein, we review the types of RONS, how they are implicated in several diseases, and the types of nanoparticles with inherent antioxidant capability, their mechanisms of action, and their biological applications.  相似文献   
23.
Corynebacterium urealyticum is usually resistant to multiple antibiotics. We analyzed whether previous hospitalization and/or the use of antibiotics was a factor associated with the appearance of resistance to different antibiotics in C. urealyticum. Our findings suggest that resistant strains of C. urealyticum are likely to be acquired directly from the hospital environment and that the use of antibiotics in the hospital setting could favor the appearance of multiresistant strains.  相似文献   
24.
Arranging office space into a single open room offers advantages in terms of easy exchange of information and interaction among coworkers, but reduces privacy and acoustic comfort. Thus, the purpose of this work was to evaluate the acoustic quality of a real open-plan office and to propose changes in the room to improve the acoustic conditioning of this office. The computational model of the office under study was calibrated based on RT and STI measurements. Predictions were made of the RT and STI, which generated the radius of distraction r(D), and the rate of spatial decay of sound pressure levels per distance doubling DL(2) in the real conditions of the office and after modifications of the room. The insertion of dividers between work stations and an increase in the ceiling's sound absorption improved the acoustic conditions in the office under study.  相似文献   
25.
In this paper, a model for oligopolistic competition in electricity markets is presented. Most previous proposed models have been static and focused only on the energy market incentives for strategic behavior. In contrast, in this paper, a multiperiod market for energy and spinning reserve (SR) is considered. By including such factors, the competition among participants is modeled with more realism. Competition in the energy market is modeled by means of conjectured supply functions, while conjectured reserve-price response functions are used to consider the generators' ability to alter the SR prices. The resulting equilibrium problem is modeled in terms of complementarity conditions. Based upon a complementarity model, the opportunity cost between the energy and SR markets is derived for oligopolistic markets. The proposed model is illustrated by a six-node network using a dc approximation.  相似文献   
26.
27.
This study examined the effects of O3 and hot water treatments on the epidermis of Golden papaya fruit. Heat treatments were applied in a hot water brushing (HWB) system. Papayas were brushed under a pressurized hot water rinse stage at 45, 55 and 65 °C for 60 s. In the HWB treatment, 4 ppm ozone was applied to the papayas for 1 or 2 min. The results show that ozone applications did not affect the fruit's cuticular surface, while heat treatments allowed natural fissures on the fruit epidermis to recover. Several crystalloid forms were identified on the epidermis of the papayas after the heat treatments. The predominant crystalloid forms on papayas are tubular and there is a positive response to temperature; the higher the temperature, the larger and more frequent the tubular crystalloids.  相似文献   
28.
The intensification of gas-solids contact in the fuel reactor of a chemical looping combustion system is enhanced with the installation of ring-type internals. This can be a key issue for achieving the necessary fuel conversion rates. Wedged rings, previously designed and tested, were found to increase the particle concentration in the counter current section of the fuel reactor and hence, to achieve a more homogeneous particles concentration along this zone. The present work investigates the effect of the mentioned internals on the residence time distribution of particles in the fuel reactor of a dual circulating fluidized bed system for chemical looping. The study was carried out in a cold flow model especially designed for the fluid-dynamic analysis of the system equipped with a recently developed residence time measurement device based on the detection of ferromagnetic tracer particles through inductance measurement. Ring internals proved the positive effect on the particles residence time, the residence time distribution is more symmetric and shows lower dispersion, the flow pattern is more plug-flow-like, these effects are intensified with the reduction of the aperture ratio of the rings. On the other hand, the upward particle transport in the counter-current zone of the fuel reactor also increases with the installation of the rings, increasing the bypass flow of solids through the fuel reactor's return loop (internal circulation). For high internal circulation rates the solids residence time distribution of the fuel reactor is dominated by the bypass effect. The findings may be used for focused design improvement of the investigated fluidized bed system.  相似文献   
29.
Universal Access in the Information Society - This paper aims to present the results of a systematic review focused on usability evaluation methods for serious games (SG) of mobile devices...  相似文献   
30.
Efforts to engineer recombinant antibodies for specific diagnostic and therapy applications are time consuming and expensive, as each new recombinant antibody needs to be optimized for expression, stability, bio-distribution, and pharmacokinetics. We have developed a new way to construct recombinant antibody-like “devices” by using a bottom-up approach to build them from well-behaved discrete recombinant antibody domains or “parts”. Studies on antibody structure and function have identified antibody constant and variable domains with specific functions that can be expressed in isolation. We used the SpyTag/SpyCatcher protein ligase to join these parts together, thereby creating devices with desired properties based on summed properties of parts and in configurations that cannot be obtained by using genetic engineering. This strategy will create optimized recombinant antibody devices at reduced costs and with shortened development times.  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