全文获取类型
收费全文 | 439篇 |
免费 | 26篇 |
专业分类
电工技术 | 11篇 |
化学工业 | 131篇 |
金属工艺 | 4篇 |
机械仪表 | 12篇 |
建筑科学 | 6篇 |
能源动力 | 9篇 |
轻工业 | 44篇 |
石油天然气 | 1篇 |
无线电 | 54篇 |
一般工业技术 | 84篇 |
冶金工业 | 59篇 |
自动化技术 | 50篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 10篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 6篇 |
2018年 | 13篇 |
2017年 | 25篇 |
2016年 | 7篇 |
2015年 | 10篇 |
2014年 | 20篇 |
2013年 | 22篇 |
2012年 | 20篇 |
2011年 | 35篇 |
2010年 | 18篇 |
2009年 | 15篇 |
2008年 | 11篇 |
2007年 | 18篇 |
2006年 | 10篇 |
2005年 | 14篇 |
2004年 | 10篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 11篇 |
1999年 | 12篇 |
1998年 | 29篇 |
1997年 | 15篇 |
1996年 | 19篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 12篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有465条查询结果,搜索用时 15 毫秒
71.
Manali Kamath Mukund Arunraj Rex Ramakrishnan Gautham Subramaniam Ramya Mohandass 《Food science and biotechnology》2019,28(2):609-614
Food Science and Biotechnology - Spirulina has emerged as the next-generation dietary supplement owing to its health benefits. Despite the advantages, there have been reports of contamination by... 相似文献
72.
Arumugham Sukanya Rajendran Rajeswari Kamatchigounder Subramaniam Murugan 《International journal of imaging systems and technology》2020,30(3):716-730
Recent research suggests that the cardiovascular diseases (CVDs), seem to be the foremost cause of mortality among the world populace. Three dimensional (3D) imaging modality such as computed tomography angiography(CTA) is a standard noninvasive imaging modality which has great potentials for the visualization of heart and coronary arteries. This article presents a fully automated method for coronary artery extraction using modified Frangi's vesselness measure and region based segmentation. In this article, grayness and gradient based measures are used while computing Frangi's vesselness measure to improve the extraction of coronary arteries. The obtained vesselness measures are utilized for automatically computing the location of ostia. The locations of ostia are then used as starting seed points in region growing segmentation to extract coronary arteries. Three major coronary arteries, namely the left anterior descending artery (LAD), left circumflex artery (LCX) and right coronary artery (RCA) are segmented using the proposed method and the centerlines are extracted for the main coronary branches. The performance of the proposed method is evaluated using 12 3D CCTA data set. The experimental results reveal that during the calculation of modified Frangi's vesselness measure the proposed method gives improved results. The qualitative results obtained during the segmentation stage are also convincing. The average segmentation accuracy and overlap measure of the proposed method are 97.4% and 77.86%, respectively. Hence, the proposed automated approach can detect and extract coronary arteries in CCTA images with high performance. 相似文献
73.
Nine heavily fertilized soils were collected from southern and central Norway. A greenhouse experiment in the phytotron was conducted to evaluate the P supplying capacities of these soils at different temperatures (9, 12 and 18 °C). The crops were grown in succession and the sequence was oat, rye grass (cut twice), oat, rape and oat. Effect of temperature on dry matter (DM) yield and P uptake was more marked up to the fourth crop but the effect varied among crops. The DM yields of oat and rape increased with increasing temperature but the opposite was the case with rye grass. The yield differences among soils at 12 °C were highly significant (p < 0.01) in contrast to 9 and 18 °C. The amount of P taken up by plants in these soils was highest at 18. °C. The P supplying capacity was highest in the soils with higher content of organic P. Generally, the soils of very fine and coarse texture classes failed to supply enough P to crops to avoid P deficiency in the successive crops. Soil P test (P-NH4-lactate) values in most of the soils increased with increasing temperatures. The highest temperature effect was seen in the Særheim sand soil. Soil P test extractants P-AL, Bray-1 and Colwell-P were used to determine P in the soil after each harvest and the soil P test values were compared with P uptake by crops. Only the P-AL extractant was significantly correlated to cumulative P removal (CPR) by plants in most of the soils. Regression equation was calculated for each soil. The value of removed P per harvest (RPH) varied from 10.33 to 20.87 mg P kg–1 soil. Phosphorus drawdown slope was determined for each soil and the number of consecutive harvests necessary to reduce the P-AL value to a normal level (110 mg P kg–1 soil) was calculated. The drawdown slope varied widely (1.257–2.801) and this reflected the P buffer capacity and the number of crops required to lower the soil test P value to a normal level. The highest drawdown slope was found in the soils with higher P supplying capacities. The Bray-1 extractant was significantly correlated in the soils with higher buffer capacity but the Colwell-P method did not show significant correlation in any of the soils. 相似文献
74.
Self-sustained, isothermal oscillations in outlet species concentrations were observed under certain steady inlet conditions in the case of the CO—NO—O2—H2O reaction system on Pt/γAl2O3 catalyst in a fixed-bed tubuiar reactor. The oscillations were mostly aperiodic, and for fixed inlet concentrations of the other species, they occurred in a rather narrow window of inlet oxygen concentrations near the stoichiometric point. The amplitude and frequency of these oscillations were affected by temperature and by the inlet concenlrations of CO and NO. Systemalic experiments, conducted to understand the cause of these oscillations, revealed that the catalyst aging procedure and the presence of water vapor induced the complex dynamic behavior observed in the CO—NO—O2—H2O system. The oscillations are explained qualitatively in terms of the competition among the various reactants for adsorption and subsequent reaction on the catalyst surface. 相似文献
75.
Yen-Liang Lai Yu-Ying Lin Subramaniam Sadhasivam Che-Yung Kuan Chih-ying Chi Guo-Chung Dong Feng-Huei Lin 《Journal of Polymer Research》2018,25(2):49
Osteoarthritis (OA) is a degenerative joint disease affecting millions of peoples worldwide. Though the etiology of OA includes joint injury, obesity, aging, and heredity, oxidative stress is majorly considered as the hallmark of OA initiation and clinical progression. Traditional pharmacologic therapies such as acetaminophen, non-steroidal anti-inflammatory drugs, and opioids are effective only against relieving pain and not capable of reverting damaged cartilage. Bletilla striata is a chinese herb majorly reported for its wound healing and anti-inflammatory property. The objective of this study is to demonstrate the potential of Bletilla striata polysaccharide (BSP) as a biomaterial for oxidative stress induced cartilage tissue repair. The polysaccharide extracted and purified from B. striata was characterized by Fourier-Transform Infrared (FT-IR) Spectrometer and 1H, 13C Nuclear Magnetic Resonance (NMR) Spectrometer. Rheological measurements of BSP hydrogel were performed using a rheometer under the frequency sweep model. The BSP also showed antioxidant effects by ABTS antioxidant activity assay. The biocompatibility and cytotoxicity of BSP was demonstrated by WST-1 and LDH assay. H2O2 induced oxidative stress was selected to generate osteoarthritic chondrocytes and its detrimental effect was demonstrated by live/dead staining. Finally, the quantitative gene expression of ECM-related genes was studied by RT-PCR in BSP treated and non-treated groups. The outcome of this study has revealed that the down-regulation of catabolic gene expression by BSP treatment may open-up the development of new therapeutic approaches in OA. 相似文献
76.
Method for Direct Determination of Glassy Phase Dissolution in Hydrating Fly Ash‐Cement System Using X‐ray Diffraction 下载免费PDF全文
Gangapatnam V. P. Bhagath Singh Kolluru V. L. Subramaniam 《Journal of the American Ceramic Society》2017,100(1):403-412
A method for quantitative X‐ray diffraction analysis is developed for direct determination of the glassy phase content of fly ash in a hydrating binary blend of cement and low‐calcium, siliceous fly ash. The intensity contributions of the unhydrated glassy phase of fly ash and the amorphous reaction products to the intensity pattern of the total amorphous phase in the hydrating binary blend are obtained by decomposition of the total intensity signature as a sum of component pseudo Voigt (PV) peaks. An experimental program involving binary blends with three different low calcium siliceous fly ashes and two different curing temperatures is reported. The centers of the component PV peaks of the fly ash glassy phase fitted to the overall intensity pattern are found to be invariant. The glassy phase content of hydrating binary blends determined from the XRD method were found to agree well with the values obtained from a selective dissolution method. 相似文献
77.
Structural Characteristics and Electrical Conductivity of Spark Plasma Sintered Ytterbia Co‐doped Scandia Stabilized Zirconia 下载免费PDF全文
Vandana Shukla Ashutosh Kumar Ishamol Labbaveettil Basheer Kantesh Balani Anandh Subramaniam Shobit Omar 《Journal of the American Ceramic Society》2017,100(1):204-214
The effect of replacing Sc2O3 with Yb2O3 on the structural and electrical properties of xYb2O3–(12–x)Sc2O3–88ZrO2 has been investigated. Spark plasma sintering technique is employed to fabricate dense bulk samples from the nano‐sized powders. X‐ray diffraction and transmission electron microscopy performed on pellets indicate the existence of cubic and rhombohedral phases in 12ScSZ, and a single cubic phase in all the co‐doped compositions. However, Raman spectroscopic studies suggest the presence of a metastable tetragonal t″‐phase along with rhombohedral phases in 12ScSZ, whereas a single cubic phase in all the co‐doped compositions. Significant enhancement in the conductivity of grain and grain boundary is observed on replacing Sc2O3 with Yb2O3. In the intermediate temperature range, 1Yb11ScSZ exhibits the highest, while 12ScSZ shows the lowest conductivity values, which is attributed to corresponding phases present in that range. Through co‐doping with >1 mol% Yb2O3 leads to conductivity decrease, but the value remains higher than that of 12ScSZ. A sharp conductivity change is observed in 12ScSZ and 1Yb11ScSZ samples, which is attributed to partial phase transition as well to the formation of cation‐vacancy complexes. In this work, the beneficial effect of Yb2O3 co‐doping in 12ScSZ on the phase and conductivity has been highlighted. 相似文献
78.
Intensified and safe ozonolysis of fatty acid methyl esters in liquid CO2 in a continuous reactor 下载免费PDF全文
Michael D. Lundin Andrew M. Danby Geoffrey R. Akien Padmesh Venkitasubramanian Kevin J. Martin Daryle H. Busch Bala Subramaniam 《American Institute of Chemical Engineers》2017,63(7):2819-2826
We demonstrate a continuous reactor for performing the ozonolysis of fatty acid methyl esters (FAMEs) using liquid CO2 as solvent. The fast reaction kinetics allows the use of small‐volume reactors to completely convert the FAMEs, forming secondary ozonides as the primary products. The short residence times also help maximize the yields of the secondary ozonides by minimizing over‐oxidation and the formation of oligomeric products. The liquid CO2 medium promotes safe reactor operation by providing an essential fraction of overall reactor cooling and by diluting the vapor phase organics. We also demonstrate a continuous stirred reactor for the safe thermal decomposition of the secondary ozonides to their corresponding acids and aldehydes. Using a lumped kinetic model for the thermal decomposition of the ozonolysis products, we estimate activation energy values of 108.6 ± 0.6 kJ mol?1 for the decomposition of secondary ozonides and 122 ± 3 kJ mol?1 for the decomposition of the undesired oligomeric species. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2819–2826, 2017 相似文献
79.
We have successfully developed, for the first time, a novel polymer-lipid hybrid nanocontainer with controlled permeability functionality. The nanocontainer is made by nanofabricating holes with desired dimensions in an impermeable polymer scaffold by focused ion beam drilling and sealing them with lipid bilayers containing remote-controlled pore-forming channel proteins. This system allows exchange of solutions only after channel activation at will to form temporary pores in the container. Potential applications are foreseen in bionanosensors, nanoreactors, nanomedicine, and triggered delivery. 相似文献
80.
Ymeti A Greve J Lambeck PV Wink T van Hövell SW Beumer TA Wijn RR Heideman RG Subramaniam V Kanger JS 《Nano letters》2007,7(2):394-397
We report the application of an integrated optical Young interferometer sensor for ultrasensitive, real-time, direct detection of viruses. We have validated the sensor by detecting herpes simplex virus type 1 (HSV-1), but the principle is generally applicable. Detection of HSV-1 virus particles was performed by applying the virus sample onto a sensor surface coated with a specific antibody against HSV-1. The performance of the sensor was tested by monitoring virus samples at clinically relevant concentrations. We show that the Young interferometer sensor can specifically and sensitively detect HSV-1 at very low concentrations (850 particles/mL). We have further demonstrated that the sensor can specifically detect HSV-1 suspended in serum. Extrapolation of the results indicates that the sensitivity of the sensor approaches the detection of a single virus particle binding, yielding a sensor of unprecedented sensitivity with wide applications for viral diagnostics. 相似文献