全文获取类型
收费全文 | 244篇 |
免费 | 11篇 |
国内免费 | 2篇 |
专业分类
化学工业 | 66篇 |
金属工艺 | 4篇 |
机械仪表 | 5篇 |
建筑科学 | 11篇 |
能源动力 | 10篇 |
轻工业 | 30篇 |
水利工程 | 6篇 |
石油天然气 | 4篇 |
无线电 | 19篇 |
一般工业技术 | 50篇 |
冶金工业 | 11篇 |
原子能技术 | 8篇 |
自动化技术 | 33篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 15篇 |
2020年 | 6篇 |
2019年 | 10篇 |
2018年 | 19篇 |
2017年 | 30篇 |
2016年 | 16篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 10篇 |
2011年 | 25篇 |
2010年 | 11篇 |
2009年 | 11篇 |
2008年 | 13篇 |
2007年 | 12篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2000年 | 1篇 |
1998年 | 10篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
排序方式: 共有257条查询结果,搜索用时 15 毫秒
1.
El-Denglawey A. Issa Shams A. M. Saddeek Yasser B. Tekin H. O. Zakaly Hesham M. H. 《Journal of Inorganic and Organometallic Polymers and Materials》2021,31(10):3934-3942
Journal of Inorganic and Organometallic Polymers and Materials - This work aimed to investigate the impact of Lead-fluoride based glasses via theoretical and simulation techniques on mechanical and... 相似文献
2.
Effect of flexure induced transverse crack and self-healing on chloride diffusivity of reinforced mortar 总被引:2,自引:0,他引:2
Mustafa Şahmaran 《Journal of Materials Science》2007,42(22):9131-9136
Cracks in reinforced concrete are unavoidable. Durability is of increasing concern in the concrete industry, and it is significantly
affected by the presence of cracks. The corrosion of reinforcing steel due to chloride ions in deicing salts or sea-water
is a major cause of premature deterioration of reinforced concrete structures. Although, it is generally recognized that cracks
accelerate the ingress of chlorides in concrete, a lack of consensus on this subject does not yet allow reliable quantification
of their effects. The present work studies the relationship between crack widths and chloride diffusivity. Flexural load was
introduced to generate cracks of width ranging between 29 and 390 μm. As crack width was increased, the effective diffusion
coefficient was also increased, thus reducing the initiation period of corrosion process. For cracks with widths less than
135 μm, the effect of crack widths on the effective diffusion coefficient of mortar was found to be marginal, whereas for
crack widths higher than 135 μm the effective diffusion coefficient increased rapidly. Therefore, the effect of crack width
on chloride penetration was more pronounced when the crack width is higher than 135 μm. Results also indicate that the relation
between the effective diffusion coefficient and crack width was found to be power function. In addition, a significant amount
of self-healing was observed within the cracks with width below 50 μm subjected to NaCl solution exposure. The present research
may provide insight into developing design criteria for a durable concrete and in predicting service life of a concrete structures. 相似文献
3.
This paper presents a space-domain method of moments (MoM) solution to the problem of a strip dipole on a dielectric slab. The solution involves the use of a special junction basis function which models the nearly singular polarization currents in the vicinity of the strip/dielectric junction 相似文献
4.
Aziz Tekin Melih Cizmeci Hulya Karabacak Muammer Kayahan 《Journal of the American Oil Chemists' Society》2002,79(5):443-445
Trans FA (TFA), solid fat contents (SFC), and slip melting points of 12 different tub and stick margarines marketed in Turkey were
examined in this study. No trans isomers were found in four margarines, which suggests they were formulated from interesterified or blended fats and oils.
The products with no TFA generally had more short-chain saturated FA, which suggests coconut oil-based oil components. TFA
content of the other 10 products varied from 7.7 to 37.8%. Compared to the products formulated in North America, Turkish margarines
contain more TFA and have higher SFC. 相似文献
5.
T.A. Taha Sultan Alomairy S.A. Saad H.O. Tekin M.S. Al-Buriahi 《Ceramics International》2021,47(14):20201-20209
55 B2O3 – 15 SiO2 – 30 Na2O: x WO3, (x ranging from 0 to 5 wt%) glass composites were prepared according to the melt-quenching procedure. The prepared samples were characterized via X-ray diffraction and broad band dielectric spectroscopy (viz., dielectric constant (ε1), tanδ and AC conductivity (σAC) over a wide range of frequency and temperature). No sharp peaks were shown in the XRD pattern and is evidence of the amorphous nature of the samples. It turns out that the values of ε1 and ε2 are increasing at higher temperatures particularly at lower frequencies. The energy barrier height, WM values decreased as 0.27, 0.25 and 0.22 while showed value of 0.29 eV for 5.0 wt% WO3. In the dielectric modulus plots, two relaxation processes are found especially on the higher temperature side. It also shifted a higher frequency with increasing temperature. The values of exponent s have been found to lie between 0.48 and 0.74, which confirms that the conduction mechanism in the glass samples follows the correlated barrier hopping model. By calculating the activation energy associated with the relaxation processes and DC conductivity, it was found that the values are close, which indicates that the same charges contribute to the two processes. 相似文献
6.
7.
Trend Assessment by the Innovative-Şen Method 总被引:1,自引:0,他引:1
İsmail Dabanlı Zekai Şen Mehmet Öner Yeleğen Eyüp Şişman Bülent Selek Yavuz Selim Güçlü 《Water Resources Management》2016,30(14):5193-5203
Hydro-meteorological time series may include trend components mostly due to climate change since about three to four decades. Trend detection and identification in a better and refined manner are among the major current research topics in water resources domain. Even though different methodologies can be found for trend detection in literature, two well-known procedures are the Mann-Kendall (MK) trend test and recently innovative-?en trend method, which provides different aspects of the trend. The theoretical basis and application of these two methods are completely different. The MK test gives a holistic monotonic trend without any categorization of the time series into a set of clusters, but the innovative-?en method is based on cluster and provides categorical trend behavior in a given time series. The main purpose of this paper is to provide important differences between these two approaches and their possible similarities. The applications of the two approaches are given for hydro-meteorological records including relative humidity, temperature, precipitation and runoff from Ergene drainage basin in the north-western part of Turkey. It is observed that although MK trend test does not show significant trend almost in all the cases, the innovative-?en approach yields trend categorizations as “very low”, “low”, “medium” “high” and “very high”, which should be taken into consideration in future flood (“very high”) and drought (“very low”) studies. 相似文献
8.
Berdan Ulas Aykut Caglar Sakir Ylmaz Umit Ecer Yonca Yilmaz Tekin Sahan Hilal Kivrak 《国际能源研究杂志》2019,43(15):8985-9000
In this study, multiwall carbon nanotube (MCNT)‐supported Pd (Pd/MWCNT) catalysts are prepared by using NaBH4 reduction method. In order to maximize the oxidation and reduction of H2SO4, synthesis conditions (Pd ratio, molar ratio of NaBH4/K2PdCl4, volume of deionized water, and duration of agitation) are optimized by using response surface methodology (RSM). The optimum synthesis conditions are determined as 58.2% of Pd by weight, 154.6 molar ratio of NaBH4 to K2PdCl4, 19.48 mL of deionized water, and 186.16 min of agitation duration. The effect of electrochemical measurement conditions on the oxidation kinetics of Pd/MWCNT is also investigated by RSM. The optimum electrochemical measurement conditions are found as 10 μL of catalyst mixture, 90°C of H2SO4 solution, and 5.5 M H2SO4. The Pd/MWCNT, Pd50Ag50/MWCNT, and Pd65.6Ag33.6Cr0.80/MWCNT catalysts prepared under optimized conditions are characterized by using X‐ray diffraction, transmission electron microscopy, N2 adsorption‐desorption, and inductively coupled plasma mass spectrometry. The crystallite sizes of these catalysts are found as 4.85, 5.66, and 5.26 nm for Pd/MWCNT, Pd50Ag50/MWCNT, and Pd65.6Ag33.6Cr0.80/MWCNT catalysts, respectively. Isotherms of all these catalysts are found to be similar to Type V isotherms with H3 hysteresis loop. The average particle size of Pd50Ag50/MWCNT and Pd65.6Ag33.6Cr0.80/MWCNT catalysts are determined as 5.2 and 9.2 nm, respectively. Electrochemical performance of as‐prepared catalysts is evaluated by using cyclic voltammetry and chronoamperometry. The formic acid electrooxidation (FAEO) activities are found as 18.9, 27.8, and 51.6 mA/cm2 for Pd/MWCNT, Pd50Ag50/MWCNT, and Pd65.6Ag33.6Cr0.80/MWCNT, respectively. Pd65.6Ag33.6Cr0.80/MWCNT shows the highest activity and stability. Optimization of synthesis conditions and electrochemical measurement parameters allow us to obtain very good electrochemical activity and stability for FAEO reaction compared with anode catalysts in the literature. 相似文献
9.
F. İşık M. A. Sabaner Duygu Erboz Taylan Şahinbaş A. Bayri 《Journal of Superconductivity and Novel Magnetism》2017,30(11):3065-3070
The symmetry of the [FeC17H31N7]2+ novel compound is close to octahedral which has spin crossover properties (SCO). In this study, geometrical optimization, IR vibration frequencies, and HOMO-LUMO energy differences at various temperatures of the compound were calculated by DFT. It is realised that the computed splitting energies and splitting free enthalpies together with the mole fraction of HS state are compatible with the experiment. 相似文献
10.
A comparative study of AISC-360 and EC3 strength limit states 总被引:1,自引:1,他引:0
A study has been undertaken to evaluate the similarities and differences between the steel building design specifications
used in the United States and Europe. Expressions for nominal strength presented in the AISC-360 Specification and the Eurocode
3 Specification were compared for fundamental limit states. In particular, rules for cross-section classification, tension
members, compression members, I-shaped members subjected to flexure, I-shaped members subjected to shear, and fasteners were
studied. Results of the investigation revealed that, in general, both specifications provide nominal capacities that are close
to each other. Significant differences were reported for some limit states such as flexure in I-shaped members with non-compact
flanges, shear and lateral torsional buckling in I-shaped members, and bearing strength at bolt holes. In this paper, the
details of the comparative study are presented along with observations that are useful for practicing engineers. 相似文献