全文获取类型
收费全文 | 251篇 |
免费 | 11篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 75篇 |
金属工艺 | 8篇 |
机械仪表 | 5篇 |
建筑科学 | 16篇 |
能源动力 | 16篇 |
轻工业 | 19篇 |
水利工程 | 1篇 |
石油天然气 | 4篇 |
无线电 | 17篇 |
一般工业技术 | 34篇 |
冶金工业 | 22篇 |
原子能技术 | 8篇 |
自动化技术 | 35篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 8篇 |
2021年 | 16篇 |
2020年 | 16篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 6篇 |
2014年 | 9篇 |
2013年 | 24篇 |
2012年 | 6篇 |
2011年 | 10篇 |
2010年 | 10篇 |
2009年 | 26篇 |
2008年 | 22篇 |
2007年 | 10篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1977年 | 3篇 |
1976年 | 1篇 |
排序方式: 共有264条查询结果,搜索用时 0 毫秒
51.
Maziyar M. Khansari Lioudmila V. Sorokina Prithviraj Mukherjee Farrukh Mukhtar Mostafa Rezazadeh Shirdar Mahnaz Shahidi Tolou Shokuhfar 《JOM Journal of the Minerals, Metals and Materials Society》2017,69(8):1340-1347
Stem cells are recognized by their self-renewal ability and can give rise to specialized progeny. Hydrogels are an established class of biomaterials with the ability to control stem cell fate via mechanotransduction. They can mimic various physiological conditions to influence the fate of stem cells and are an ideal platform to support stem cell regulation. This review article provides a summary of recent advances in the application of different classes of hydrogels based on their source (e.g., natural, synthetic, or hybrid). This classification is important because the chemistry of substrate affects stem cell differentiation and proliferation. Natural and synthetic hydrogels have been widely used in stem cell regulation. Nevertheless, they have limitations that necessitate a new class of material. Hybrid hydrogels obtained by manipulation of the natural and synthetic ones can potentially overcome these limitations and shape the future of research in application of hydrogels in stem cell regulation. 相似文献
52.
A. M. Al‐Mukhtar 《Fatigue & Fracture of Engineering Materials & Structures》2013,36(12):1352-1361
To better understand the crack closure and propagation, an analytical model is established. The residual stress effect on fatigue crack growth equations has been considered using the residual stress intensity factor (SIF) (Kres). The joint geometries, residual stress distributions (σres) and residual stress ratio (Rres) were considered also. Kres are calculated using the analytical weight function (WF) method and different residual stress distributions. It is to be emphasized that the current approach is little investigated. This is because the WF has already been developed to calculate SIF for an existing crack. The current approach calculates Kres for the crack that initiates and propagates until failure. Different stress distributions have been used, and Rres is defined. The validity of using the WF has been shown. SIF due to applied load (Kapp) and applied stress ratio (Rapp) have been considered. Fatigue crack growth rate was investigated in accordance with the current approach. The results have been verified and benchmarked. 相似文献
53.
Abdulkadir Bayr H brahim Halilolu A Necdet Sirkeciolu N Mevlüt Aras 《Journal of the science of food and agriculture》2006,86(1):163-168
The muscle fatty acid (FA) composition of 12 selected marine fish species living in Turkish waters was determined. FA profiles of muscle were compared in terms of total and individual saturated (SFAs) and unsaturated fatty acids. Total SFA, monounsaturated fatty acid (MUFA), n‐3 polyunsaturated fatty acid (n‐3 PUFA) and n‐6 polyunsaturated fatty acid (n‐6 PUFA) contents as well as n‐3/n‐6 FA and eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) ratios differed (P < 0.01) in all fish species. Palmitic acid (16:0) among total SFAs, oleic acid (18:1n‐9) among MUFAs, DHA (22:6n‐3) among n‐3 PUFAs and 18:2n‐6 and 20:4n‐6 among n‐6 PUFAs were the most abundant FAs. The ratio of n‐3/n‐6 PUFA contents, indicating the availability of n‐3 PUFAs that are beneficial for human health, ranged from 2.67 to 12.61. The EPA/DHA ratio was between 0.17 and 0.83 in the marine fish species studied. Copyright © 2005 Society of Chemical Industry 相似文献
54.
Immobilizing nuclear wastes has been one of the most important challenges in nuclear technology. A method to quantify and monitor the radiation damage to waste immobilizing crystalline materials like zircon is proposed. This method will make use of proton/ion channelling measurements of the crystalline containment sample or test crystalline sample placed in the crystalline or amorphous containment of nuclear waste for a long time from years to a few decades and the mathematical method to determine the structure collapse rate of the containment material using channelling measurements. Implementation procedure of this method/technique for radiation damage measurement in nuclear waste container materials is described. 相似文献
55.
Distribution of the median nerve in the arm is not normally subjected to variation. This report represents a case of complete absence of the musculocutaneous nerve from the lateral cord of the brachial plexus. The innervation of the muscles of the anterior (flexor) compartment of the arm was by direct branches from the median nerve. This variation was present in both the right and left limbs. 相似文献
56.
Nausheen Hameed Siddiqui Syed Abid Ali Iqbal Azhar Omer Mukhtar Tarar Zafar Alam Mahmood 《分离科学与技术》2018,53(15):2427-2434
Influence of variables has a great impact upon yield of pectin. The present study was organized to harmonize these variables and examine the extracted pectin. In view of this, bio-characterizion and structure analysis of pectin through FTIR was performed. Additionally, a polydispersity and particle size study was also conducted using dynamic light scattering (DLS) of the Manilkarazapota fruit peel. The best extraction variables according to the response optimization predicted model were noted as pH of 5 at 61.11°C for 90 min of heating time, which lead to a 3.7% yield. Bio-characterization revealed that pectin extracted at pH 5 has characteristics similar to HM pectin influence of methoxyl content, degree of esterification, and Galacturonic acid content at 5.11%, 73. 63%, and 77.7%, respectively. The FTIR spectrum depicted a similar surface structure to food-grade pectin. DLS studies revealed that extracted pectin at pH 5 has a particle size in the range of 390.21–421.17 nm and polydispersity (?) of 28.2%-29.3%. These findings indicate that sapodilla is a potential source of pectin for food and pharmaceutical preparation. 相似文献
57.
Machine Intelligence Research - This paper addresses an advanced analysis system for the identification of alcoholic brain states from electroencephalogram (EEG) data in an automatic way. This... 相似文献
58.
Abdulkadir Akin Ipek BazAuthor VitaeAlexandre SchmidAuthor Vitae Yusuf LeblebiciAuthor Vitae 《Integration, the VLSI Journal》2014
The computational complexity of disparity estimation algorithms and the need of large size and bandwidth for the external and internal memory make the real-time processing of disparity estimation challenging, especially for High Resolution (HR) images. This paper proposes a hardware-oriented adaptive window size disparity estimation (AWDE) algorithm and its real-time reconfigurable hardware implementation that targets HR video with high quality disparity results. Moreover, an enhanced version of the AWDE implementation that uses iterative refinement (AWDE-IR) is presented. The AWDE and AWDE-IR algorithms dynamically adapt the window size considering the local texture of the image to increase the disparity estimation quality. The proposed reconfigurable hardware architectures of the AWDE and AWDE-IR algorithms enable handling 60 frames per second on a Virtex-5 FPGA at a 1024×768 XGA video resolution for a 128 pixel disparity range. 相似文献
59.
The electrochemical oxidation of nicotine was studied in aqueous as well as micellar media at a pencil graphite electrode using cyclic, differential pulse and square-wave voltammetric techniques. The compound was oxidized irreversibly at low positive potentials in one (in acidic and neutral media) or two (in alkaline media) oxidation steps. The response was evaluated with respect to pH, scan rate, addition of surfactant and other variables. For analytical purposes, very resolved voltammetric peaks at +0.84 V (versus Ag/AgCl) were obtained in phosphate buffer at pH 7.0 containing 2 mM sodium dodecylsulfate using square-wave mode. The process could be used to determine nicotine concentrations in the range of 7.6–107.5 μM with a detection limit of 2.0 μM (0.33 mg L−1). The proposed method was applied to the determination of nicotine in different brands of commercial cigarettes. 相似文献
60.
Specific concerns of Pakistan in the context of energy security issues and geopolitics of the region 总被引:1,自引:0,他引:1
The global and regional energy security in future is not likely to be threatened as much by the shortage of resources as it is likely to be endangered by the disruption of supplies and availability of tradable resources: threatened by growing terrorism and geopolitical conflicts. Pakistan's geo-strategic position and its importance act to both influence and undermine its energy security issues. It has the potential to provide a corridor for regional energy trade but it is ranked among the top nations exposed to potential threat of terrorist attacks because of the consequences of its role in the major geopolitical expeditions of the recent past. The paper examines the concerns of Pakistan emanating from the regional and global geopolitics of energy from Pakistan's viewpoint. 相似文献