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321.
锥束射线三维大视场工业CT成像方法研究   总被引:3,自引:0,他引:3  
傅健  路宏年  龚磊 《光学技术》2006,32(2):209-212
基于FDK重建算法和圆轨道锥束扫描的三维ICT(industrial computed tomography)因算法的简洁性和工程实现的可行性已成为目前主要的3D-ICT成像技术。由于受探测器长度的限制,该技术的扫描视场小,所以可检构件尺寸受到限制。为解决较大尺寸构件3D-ICT的检测问题,讨论了一种仅需旋转检台偏置的大视场3D-ICT成像方法,推导了基于FDK原理的滤波反投影(filter back-projection,FBP)重建算法。计算机模拟和实验结果证明了该技术的正确性。分析表明,其水平方向的有效扫描视野比基于FDK的圆轨道锥束扫描三维CT提高了80%以上。  相似文献   
322.
Fruits maintain the image as the richest sources of vitamins. Focusing on apricots, utilization of apricot species for many applications is possible due to its various benefits. Many research studies demonstrated different perspectives of apricot, especially in medical used as it can act as antioxidant, anti-inflammatory, and antimicrobial agents. Moreover, in the industrial sectors, apricots can be used in the production of biofuels and batteries. All components of the apricot fruit, including seeds and kernels have been found to possess significant interest. This review is to breach the knowledge gap regarding the key nutrients and chemicals of apricot fruit, contributing to its health-promoting properties to emphasize the noble importance of this fruit in the diet and in the management of several diseases. We also cover the application of apricots in the industry that could be developed as a promising and sustainable source.  相似文献   
323.
The performance evaluation and optimization of an energy conversion system design of an energy intensive drying system applied the method of combining exergy and economy is a theme of global concern. In this study, a gas-type industrial drying system of black tea with a capacity of 100 kg/h is used to investigate the exergetic and economic performance through the exergy and exergoeconomic methodology. The result shows that the drying rate of tea varies from the maximum value of 3.48 gwater/gdry matter h to the minimum 0.18 gwater/gdry matter h. The highest exergy destruction rate is found for the drying chamber (74.92 kW), followed by the combustion chamber (20.42 kW) in the initial drying system, and 51.83 kW and 21.15 kW in the redrying system. Similarly, the highest cost of the exergy destruction rate is found for the drying chamber (18.497 USD/h), followed by the combustion chamber (5.041 USD/h) in the initial drying system, and 12.796 USD/h and 5.222 USD/h in the redrying system. Furthermore, we analyzed the unit exergy rate consumed and the unit exergy cost of water removal in different drying sections of the drying system, and determined the optimal ordering of each component. These results mentioned above indicate that, whether from an energy or economic perspective, the component improvements should prioritize the drying chamber. Accordingly, minimizing exergy destruction and the cost of the exergy destruction rate can be considered as a strategy for improving the performance of energy and economy. Overall, the main results provide a more intuitive judgment for system improvement and optimization, and the exergy and exergoeconomic methodology can be commended as a method for agricultural product industrial drying from the perspective of exergoeconomics.  相似文献   
324.
The growing demand in natural matrices that represent a source of dietary and nutraceutical molecules has led to an increasing interest in Cannabis sativa, considered to be a multipurpose, sustainable crop. Particularly, the considerable content in essential fatty acids (FAs) makes its derived-products useful food ingredients in the formulation of dietary supplements. In this research, the FA and triacylglycerol (TAG) composition of hempseed oils and flours were investigated using gas chromatography coupled to mass spectrometry and flame ionization detection as well as liquid chromatography coupled to mass spectrometry (LC-MS), respectively. Furthermore, a recently introduced linear retention index (LRI) approach in LC was successfully employed as a useful tool for the reliable identification of TAG species. A total of 30 FAs and 62 glycerolipids were positively identified in the investigated samples. Relative quantitative analyses confirmed linoleic acid as the most abundant component (50–55%). A favorable omega6/omega3 ratio was also measured in hemp-derived products, with the α-linolenic acid around 12–14%. Whereas, γ-linolenic acid was found to be higher than 1.70%. These results confirm the great value of Cannabis sativa as a source of valuable lipids, and the further improvement of the LRI system paves the way for the automatization of the identification process in LC.  相似文献   
325.
The commercial low-pressure column chromatographic 99Mo/99mTc generator represents a reliable source of onsite, ready-to-use 99mTc for industrial applications. These generators use fission-produced 99Mo of high specific activity, posing serious production challenges and raising proliferation concerns. Therefore, many concepts are aimed at using low-specific-activity (LSA) 99Mo. Nonetheless, the main roadblock is the low sorption capacity of the used alumina (Al2O3). This study investigates the feasibility of using commercial alumina incorporated with LSA 99Mo to develop a useful 99Mo/99mTc generator for industrial radiotracer applications. First, the adsorption profiles of some commercial alumina sorbents for LSA 99Mo were tested under different experimental conditions. Then, the potential materials to develop a 99Mo/99mTc generator were selected and evaluated regarding elution yield of 99mTc and purity. Among the sorbents investigated in this study, mesoporous alumina (SA-517747) presented a unique sorption-elution profile. It demonstrated a high equilibrium and dynamic sorption capacity of 148 ± 8 and 108 ± 6 mg Mo/g. Furthermore, 99mTc was eluted with high yield and adequate chemical, radiochemical, and radionuclidic purity. Therefore, this approach provides an efficient and cost-effective way to supply onsite 99mTc for radiotracer applications independent of fission-produced 99Mo technology.  相似文献   
326.
More than 70% of our planet is covered by extremely cold environments, nourishing a broad diversity of microbial life. Temperature is the most significant parameter that plays a key role in the distribution of microorganisms on our planet. Psychrophilic microorganisms are the most prominent inhabitants of the cold ecosystems, and they possess potential cold-active enzymes with diverse uses in the research and commercial sectors. Psychrophiles are modified to nurture, replicate, and retain their active metabolic activities in low temperatures. Their enzymes possess characteristics of maximal activity at low to adequate temperatures; this feature makes them more appealing and attractive in biotechnology. The high enzymatic activity of psychrozymes at low temperatures implies an important feature for energy saving. These enzymes have proven more advantageous than their mesophilic and thermophilic counterparts. Therefore, it is very important to explore the efficiency and utility of different psychrozymes in food processing, pharmaceuticals, brewing, bioremediation, and molecular biology. In this review, we focused on the properties of cold-active enzymes and their diverse uses in different industries and research areas. This review will provide insight into the areas and characteristics to be improved in cold-active enzymes so that potential and desired enzymes can be made available for commercial purposes.  相似文献   
327.
328.
强流质子源及低能传输线是加速器驱动次临界系统(ADS)项目注入器的重要组成部分,为了保证其工作效率设计了一种基于实验物理及工业控制系统(EPICS)架构的远程控制系统。根据被控设备硬件接口的特点及控制需求分别采用可编程控制器(PLC)和串口服务器等作为控制部件,在主控机中使用LabVIEW编程实现了对系统内所有设备的监控,并借助于DSC模块把设备状态和参数等以过程变量的形式进行网络发布。设计的控制系统具有结构简单、工作可靠的特点,已经在系统调试中发挥了重要作用。  相似文献   
329.
进行了两段法F -T合成 (MFT)Fe -Cu -K催化剂 3 0 0 0小时模试 ,考察了工艺改进后的适应性 ,催化剂稳定性及其影响因素。结果表明 ,CO转化率达到了 75~ 85 %,烃选择性达 78~ 94 %,C 5产率达 85~ 1 1 0g/NM3(CO H2 )。  相似文献   
330.
为了有效地提高面向逆向工程的工业CT图像轮廓处理的精准性和计算效率,开发了工业CT图像轮廓提取与优化系统。该系统主要包括图像处理模块、轮廓识别与提取模块、轮廓拟合与优化模块、图像处理经典算法库和数据接口等功能模块,实现了从工业CT图像到轮廓数据的三维点云与轮廓线的标准格式输出,并与逆向工程软件对接。同时,在轮廓拟合与优化模块中,提出了基于全局约束模型的轮廓拟合策略,并采用有向图分解和数值代数相结合的计算方法,提高了轮廓拟合的计算精度和效率。最后通过实例验证了系统的有效性和正确性。  相似文献   
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