全文获取类型
收费全文 | 2387篇 |
免费 | 112篇 |
国内免费 | 15篇 |
专业分类
电工技术 | 28篇 |
综合类 | 9篇 |
化学工业 | 531篇 |
金属工艺 | 72篇 |
机械仪表 | 89篇 |
建筑科学 | 75篇 |
矿业工程 | 9篇 |
能源动力 | 215篇 |
轻工业 | 375篇 |
水利工程 | 20篇 |
石油天然气 | 25篇 |
无线电 | 145篇 |
一般工业技术 | 486篇 |
冶金工业 | 90篇 |
原子能技术 | 35篇 |
自动化技术 | 310篇 |
出版年
2024年 | 10篇 |
2023年 | 43篇 |
2022年 | 86篇 |
2021年 | 105篇 |
2020年 | 99篇 |
2019年 | 98篇 |
2018年 | 129篇 |
2017年 | 128篇 |
2016年 | 111篇 |
2015年 | 75篇 |
2014年 | 88篇 |
2013年 | 229篇 |
2012年 | 150篇 |
2011年 | 151篇 |
2010年 | 114篇 |
2009年 | 152篇 |
2008年 | 155篇 |
2007年 | 109篇 |
2006年 | 80篇 |
2005年 | 60篇 |
2004年 | 43篇 |
2003年 | 42篇 |
2002年 | 24篇 |
2001年 | 15篇 |
2000年 | 18篇 |
1999年 | 14篇 |
1998年 | 30篇 |
1997年 | 16篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 12篇 |
1992年 | 14篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1979年 | 3篇 |
1976年 | 3篇 |
1971年 | 1篇 |
1970年 | 3篇 |
1968年 | 1篇 |
1967年 | 3篇 |
排序方式: 共有2514条查询结果,搜索用时 15 毫秒
191.
Nidhi Nandu Mustafa Salih Hizir Neil M. Roberston Dr. Birol Ozturk Prof. Dr. Mehmet V. Yigit 《Chembiochem : a European journal of chemical biology》2019,20(14):1861-1867
Two-dimensional MoS2 nanoparticles (2D-nps) exhibit artificial enzyme properties that can be regulated at bio-nanointerfaces. We discovered that protein lipase is able to tune the peroxidase-like activity of MoS2 2D-nps, offering low-nanomolar, label-free detection and identification in samples with unknown identity. The inhibition of the peroxidase-like activity of the MoS2 2D-nps was demonstrated to be concentration dependent, and as low as 5 nm lipase was detected with this approach. The results were compared with those obtained with several other proteins that did not display any significant interference with the nanozyme behavior of the MoS2 2D-nps. This unique response of lipase was characterized and exploited for the successful identification of lipase in six unknown samples by using qualitative visual inspection and a quantitative statistical analysis method. The developed methodology in this approach is noteworthy for many aspects; MoS2 2D-nps are neither labeled with a signaling moiety nor modified with any ligands for signal readout. Only the intrinsic nanozyme activity of the MoS2 2D-nps is exploited for this detection approach. No analytical equipment is necessary for the visual detection of lipase. The synthesis of the water-soluble MoS2 2D-nps is low costing and can be performed in bulk scale. Exploring the properties of 2D-nps and their interactions with biological materials reveals highly interesting yet instrumental features that offer the development of novel bioanalytical approaches. 相似文献
192.
Mustafa M. F. Al-Jarrah Numan A. Abdul-Latif Suham H. F. Al-Madfai Rita L. Apikian 《应用聚合物科学杂志》1989,38(3):477-482
The influence of the Al/Ti ratio of the heterogeneous Ziegler–Natta catalyst system AlEt3–TiCl4 on the isoprene polymerization in n-heptane at 30°C in a bench scale reactor was investigated. Each batch run consisted of 50 mL isoprene, 200 mL n-heptane with 0.45 and 0.5g catalyst. Conversion of isoprene and molecular weights of polyisoprene increased with increasing Al/Ti ratio, reaching their maxima values at 1.0 and 1.2, respectively. Conversion and molecular weights decreased remarkably at a higher ratio of Al/Ti. As this ratio decreases from the value of 1.2 to 0.4, the cis1,4 content in polyisoprene decreased from 97 to 25%. When the ratio of Al/Ti increased from 1.2 to 2.2 the cis-1,4 structure of polyisoprene decreased from 97 to 85%. 相似文献
193.
Influence of Storage on Physicochemical and Volatile Features of Enriched and Aromatized Wax Organogels 下载免费PDF全文
Mustafa Öğütcü Emin Yılmaz Onur Güneşer 《Journal of the American Oil Chemists' Society》2015,92(10):1429-1443
In this study, virgin olive oil (VOO) organogels were produced with beeswax (BW) and sunflower wax (SW) and enriched with β‐carotene, vitamin D3 and E as well as aromatized with strawberry, banana, and butter aromas. The physicochemical, thermal, structural, and sensorial properties of the fresh organogel samples were determined. The peroxide values, antioxidant activities, firmness, and volatile compositions of the fresh samples and those stored for 3 months were also determined. The organogels were not only stable, uniform, and homogenous during the storage period but also the added components did not affect the organogel properties. The panel defined three appearance, four texture, three mouthfeel, four aroma, and four flavor terms to describe the organogels sensorially. Moreover, the added aroma (banana, strawberry, and diacetyl‐butter) components of the fresh and stored organogels were quantified by GC/MS‐SPME. In conclusion, these results demonstrated that beeswax and sunflower wax are very suitable to preserve the aromatic characteristics of these types of spreadable products. 相似文献
194.
195.
Equilibrium,kinetics, and thermodynamics of Pd(II) adsorption onto poly(m‐aminobenzoic acid) chelating polymer 下载免费PDF全文
This study describes the equilibrium, kinetics, and thermodynamics of the palladium(II) (Pd(II)) adsorption onto poly(m‐aminobenzoic acid) (p‐mABA) chelating polymer. The p‐mABA was synthesized by the oxidation reaction of m‐aminobenzoic acid monomer with ammonium peroxydisulfate (APS). The synthesized p‐mABA chelating polymer was characterized by FTIR spectroscopy, gel permeation chromatography (GPC), thermal analysis, potentiometric titration, and scanning electron microscopy (SEM) analysis methods. The effects of the acidity, temperature, and initial Pd(II) concentration on the adsorption were examined by using batch adsorption technique. The optimum acidity for the Pd(II) adsorption was determined as pH 2. In the equilibrium studies, it was found that the Pd(II) adsorption capacity of the polymer was to be 24.21 mg/g and the adsorption data fitted better to the Langmuir isotherm than the Freundlich isotherm. The kinetics of the adsorption fitted to pseudo‐second‐order kinetic model. In the thermodynamic evaluation of the adsorption, the ΔG° values were calculated as ?16.98 and ?22.26 kJ/mol at 25–55°C temperatures. The enthalpy (ΔH°), entropy (ΔS°), and the activation energy (Ea) were found as 35.40 kJ/mol, 176.05 J/mol K, and 61.71 kJ/mol, respectively. The adsorption of Pd(II) ions onto p‐mABA was a spontaneous, endothermic, and chemical adsorption process which is governed by both ionic interaction and chelating mechanisms. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42533. 相似文献
196.
Anwer Mustafa Hilal Eatedal Alabdulkreem Jaber S. Alzahrani Majdy M. Eltahir Mohamed I. Eldesouki Ishfaq Yaseen Abdelwahed Motwakel Radwa Marzouk 《计算机系统科学与工程》2023,45(2):1129-1143
Biomedical image processing is widely utilized for disease detection and classification of biomedical images. Tongue color image analysis is an effective and non-invasive tool for carrying out secondary detection at anytime and anywhere. For removing the qualitative aspect, tongue images are quantitatively inspected, proposing a novel disease classification model in an automated way is preferable. This article introduces a novel political optimizer with deep learning enabled tongue color image analysis (PODL-TCIA) technique. The presented PODL-TCIA model purposes to detect the occurrence of the disease by examining the color of the tongue. To attain this, the PODL-TCIA model initially performs image pre-processing to enhance medical image quality. Followed by, Inception with ResNet-v2 model is employed for feature extraction. Besides, political optimizer (PO) with twin support vector machine (TSVM) model is exploited for image classification process, shows the novelty of the work. The design of PO algorithm assists in the optimal parameter selection of the TSVM model. For ensuring the enhanced outcomes of the PODL-TCIA model, a wide-ranging experimental analysis was applied and the outcomes reported the betterment of the PODL-TCIA model over the recent approaches. 相似文献
197.
M. Attia F. S. Taha H. M. Mustafa A. S. El-Nockrashy 《Molecular nutrition & food research》1988,32(3):281-284
Bench-scale refining of crude colour-fixed cottonseed oil was carried out using equipment and conditions similar to those at a local factory. Ethanolamine at 2–3% level resulted in 55–62% reduction in the oil colour, and 24–26% reduction in the refining loss over the factory treated oil. Sodium silicate at 0.14–0.47% level resulted in about 50% reduction in oil colour and 24–44% reduction in the refining loss. A two-step treatment, first with caustic soda lye then with either additives, and miscella refining using ethanolamine as an additive, resulted in superior oil colour, yet the refining losses were high. 相似文献
198.
Ayhan Mergen Yeliz İpek Hülya Bölek Mustafa Öksüz 《Journal of the European Ceramic Society》2012,32(9):2001-2005
In this study, nano sized zinc borate powder with a formula of 4ZnO·B2O3·H2O was synthesized using 2ZnO·3B2O3·3.0–3.5H2O as a starting chemical which was produced using a wet chemical method. After dissolving 2ZnO·3B2O3·3.0–3.5H2O in an ammonia solution, the clear solution was boiled until a white powder formed. The resultant powder was characterized with XRD, FTIR, TGA and TEM. XRD, FTIR and TGA results proved that the powder was belonged to the 4ZnO·B2O3·H2O. Nano composites of 4ZnO·B2O3·H2O–polyvinylchloride (PVC) were produced by injection moulding by adding 1 and 5 wt% zinc borate powders into PVC to enhance its flame retardancy. Limiting oxygen index (LOI) of virgin PVC increased from 41% to 47% and 54% for the 1 and 5 wt% zinc borate added PVC, respectively. Nano zinc borate addition into the PVC does not have considerable negative effect on the mechanical properties of zinc borate–PVC composites even at high amounts of 5 wt%. 相似文献
199.
ABSTRACT Uapcur pressure csmometry (UPO) and viscometric technique were used to reveal the true molecular weight of asphaltenes and the degree of association in solvent of different polarities at different temperatures. The number average malecular weight of unassociated asphaltenes was found to be 935 g/mcl. In n' trobenzene at 120 C. The degrees of association were determined from UPO in benzene at 37, 45, 60 C, in chlorobunzene at 37, 45, 60 and 90 C. in THE at 37, 45, 60 C and in nitrobenzene at 90 C. The degree of association determined by ulscometric method at 37, 45 and 60 C, in these soluents were found to be in approximate agrement with that found bv UPO. Data derived by means of ulscometric and osmometric methods consolidated the recognition that asphaltenes could be similar to macro-molecules structurally. 相似文献
200.
Mustafa M. F. Al-Jarrah Hussain H. Al-Soufi Rita L. Apikian H. I. Al-Saleem S. S. Naoom 《Petroleum Science and Technology》2013,31(3):249-260
ABSTRACT The number average molecular weight (Mn¯) of two Iraqi asphalts has been studied before end after thermal treatment using vapour pressure osmometery. Changes in Mn¯ values after thermal aging were compared with the changes in their physical and mechanical properties. Toluene, benzene, cyclohexane, tetrahydrofuran and carbon tetrachloride were used to fractionate the asphalts The Mn¯ of each fraction was determined before and after aging. 相似文献