全文获取类型
收费全文 | 525篇 |
免费 | 30篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 158篇 |
金属工艺 | 15篇 |
机械仪表 | 17篇 |
建筑科学 | 13篇 |
能源动力 | 35篇 |
轻工业 | 107篇 |
水利工程 | 4篇 |
石油天然气 | 13篇 |
无线电 | 37篇 |
一般工业技术 | 67篇 |
冶金工业 | 10篇 |
原子能技术 | 4篇 |
自动化技术 | 71篇 |
出版年
2024年 | 3篇 |
2023年 | 20篇 |
2022年 | 38篇 |
2021年 | 43篇 |
2020年 | 29篇 |
2019年 | 27篇 |
2018年 | 38篇 |
2017年 | 29篇 |
2016年 | 40篇 |
2015年 | 17篇 |
2014年 | 15篇 |
2013年 | 57篇 |
2012年 | 24篇 |
2011年 | 32篇 |
2010年 | 26篇 |
2009年 | 25篇 |
2008年 | 18篇 |
2007年 | 18篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有555条查询结果,搜索用时 0 毫秒
101.
Ferhat Yücedag Cigdem Atalay‐Oral Sibel Erkal Ahmet Sirkecioglu Djursun Karasartova Fikret Sahin Serife Birgül Tantekin‐Ersolmaz Fatma Seniha Güner 《应用聚合物科学杂志》2010,115(3):1347-1357
As an alternative to petroleum‐based polyol, hydroxyl containing material was prepared from linseed oil for polyurethane synthesis. Hexamethylene di‐isocyanate (HMDI) and/or 4, 4′‐methylene diphenyl di‐isocyanate (MDI) were used as isocyanate source. The polymerization reaction was carried out without catalyst. Polymer films were prepared by casting‐evaporation technique. The MDI/HMDI‐based polyurethane and its films had higher Tg and better thermal property than that of the HMDI‐based one because of the existence of benzene ring in the polymer chain. Static water contact angle was determined to be 74° and 77.5° for HMDI and MDI/HMDI‐based films, respectively. Water adsorption was found to be around 2.6–3.6% for both films. In vitro degradation of polyurethanes in phosphate buffered saline at 37°C was investigated by gravimetric method. Fourier transform infrared spectroscopy and scanning electron microscopy were used for confirmation of degradation on the polymer surface. The degradation rate of the HMDI‐based polyurethane film was found higher than that of the MDI/HMDI‐based film. Both the direct contact method and the MMT test were applied for determination of cytotoxicity of polymer films, and the polyurethane films investigated here was not cytotoxic. Silver‐containing films were prepared using Biocera A® as filler and were screened for their antibacterial performance against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and/or Bacillus subtilis. The films prepared with and without Biocera A® exhibited antibacterial activity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
102.
In this study, pure nanobrookite TiO2 thin films were successfully deposited on glass substrates with the spin-coating method using titanium butoxide and acetic acid. The particle size of TiO2 films was controlled by the water:AcAc volume ratio. This study shows that it is possible to obtain single oriented pure brookite films. The structural and optical properties of the nanobrookite TiO2 thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), spectrophotometer (NKD), and Fourier transform infrared spectrometer (FTIR). 相似文献
103.
Fatma Ben Saada 《摩擦学汇刊》2016,59(5):856-864
Failure of equipment for processing olives interrupted oil production after only 3 weeks in service. Macroscopic and microscopic analyses were used in the present investigation to analyze damaged surfaces. Observations and data suggest that failure was induced via tribocorrosion with a predominance of mechanical damage. This damage is attributed to abrasive wear combined with corrosion of AISI 304L stainless steel in olive paste (seed particles and pulp) mixed with tap water. Microscopic observations revealed fracture and localized plastic deformation in the damaged area along with a tribologically transformed structure and work-hardened surfaces. The tribological behavior of AISI 304L was determined using a pin-on-disc tribometer, and these results were compared to damage on the olive processing equipment. The steel was sensitive to tribo-oxidation, mostly due to abrasion by seeds and steel wear particles, and somewhat due to corrosion reactions with the environment. 相似文献
104.
Magdy M. Senna Ateyat M. Yossef Fatma M. Hossam Abdel Wahab M. El‐Naggar 《应用聚合物科学杂志》2007,106(5):3273-3281
Foamy low‐density polyethylene/plasticized starch (LDPE/PLST) blends at different compositions were produced in the presence of azodicarbonamide (ACA) compound as foaming agent. The LDPE/PLST blends before and after electron beam irradiation were investigated in terms of mechanical properties, bulk density, and structure morphology. Moreover, the biodegradability of these materials was evaluated by the soil burial test for 2 months, in which the buried sheets were also examined by scanning electron microscopy (SEM). The results showed that the increase of PLST content from 24 to 30% was accompanied by a decrease in the yield and break stresses of 10 and 20% for the unirradiated blends without the foaming agent, respectively. Further decrease in these mechanical parameters was observed after the foaming process. The bulk density, void fraction, cell size measurements as well as the examination by SEM illustrate clearly the cell growth of the foam structure. The soil burial test and SEM micrographs indicate the growth of microorganisms overall the blend sheets and that the blend was completely damaged after two months of burying. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
105.
Emine Sirin Karaarslan Fatma Aytaç Bilge Hilal Çadirci Merve Ağaccioğlu Emine Taştan Gülesme Yilmaz 《Journal of Adhesion Science and Technology》2013,27(23):2617-2630
The aim of the study was to compare the effects of different remineralization methods that are well established in clinical and daily use on S. mutans biofilm adhesion. In this study 72 human third molars were used. From each tooth two pieces of 4?mm x 7?mm enamel blocks were acquired. The samples were divided into 6 groups in which include 10 samples per time period (24h and 48?h) and for each remineralization method; control, flouride, ozone, CPP-ACP, arginine, novamin. After remineralization procedures, enamel surfaces were covered with saliva. 105 CFU/mL of active S. mutans culture were inoculated onto the samples. S. mutans colonies were counted with Plate Count Agar (PCA) decimal dilution method. Micromorphologic effects of different remineralization methods were observed by Scanning Electron Microscopy (SEM). The most S. mutans biofilm formation for both time periods was observed in the control group whereas the less biofilm adhesion was showed in the arginine group. There were no statistically significant differences among remineralization agents (p?>?0.05). In the control group there was statistical difference between 24?h and 48?h (p?<?0.005) but in the other study groups there were no significant difference between the time periods (p?>?0.05). Remineralization agents did not significant differ on S. mutans biofilm adhesion. 相似文献
106.
107.
Fatma Dirgenali 《仪器科学与技术》2013,41(5):575-595
Abstract Mitral valve stenosis is an important heart condition that develops when the mitral valve fails to open as wide as it should. In this study, we have performed Eigenvector based Music, FFT based Welch, and AR based Burg methods of Doppler signals real clinical data from patients with mitral valve stenosis and healthy volunteers. Using these methods, we have not only utilized power spectral density distribution graphs, but also facilitated Doppler sonograms and estimation of SBI to obtain medical information about mitral stenosis and determination of spectral broadening in the presence of mitral stenosis. In conclusion, this research has shown that frequency level of maximum power spectral density is distinctive and there is an advantage in using the EIG‐Music over the FFT‐Welch and AR‐Burg for the determination of SBI. Using the Music method among them, the calculation of SBI may help determine mitral valve stenosis. 相似文献
108.
Anwar A. Wassil Abd El-Ftaah Bastawy Farag Fatma A. Moukdad 《Drug development and industrial pharmacy》2013,39(1):57-62
ABSTRACTThe construction of PVC matrix-type β-blockers (sotalol, carvedilol, and betaxolol) ion selective electrodes and their use for direct potentiometry of their respective species are described. The proposed sensors are based on the complex ion associates of β-blockers with tungstophosphate (TP) and Ammonium Reineckate (Rein) ionophoris in poly vinyl chloride membrane (PVC) with Dioctylphthalate (DOP) plasticizer. The four electrodes (Beta-TP), (Sota-TP), (Carve-TP), and (Cave-Rein) show stable potential response with near Nernstian slope of 50.8, 33.7, 32.35, and 33 mv per decade, range of concentration 10?2–10?7 M β-blockers. Selectivity coefficients data obtained for 11 different organic and inorganic ions are presented. The electrodes have fast response time (30 and 40 s) and were used over wide range of pH 4.5–8.5. Validation of the method according to the quality assurance standers shows suitability of proposed sensors for use in the quality control assessment of these drugs. The results obtained for the determination of β-blockers with the proposed electrodes show average recoveries of 100.78% and a mean standard deviation of ±1.2. The nominal are obtained. The data agree well with those obtained by standard methods. 相似文献
109.
Fatma Taşdelen Bayram Çeki̇m Rabi̇a Aktaş 《Computers & Mathematics with Applications》2011,61(9):2412-2423
The classical Jacobi matrix polynomials only for commutative matrices were first studied by Defez et al. [E. Defez, L. Jódar, A. Law. Jacobi matrix differential equation, polynomial solutions and their properties, Comput. Math. Appl. 48 (2004) 789–803]. The main aim of this paper is to construct a multivariable extension with the help of the classical Jacobi matrix polynomials (JMPs). Generating matrix functions and recurrence relations satisfied by these multivariable matrix polynomials are derived. Furthermore, general families of multilinear and multilateral generating matrix functions are obtained and their applications are presented. 相似文献
110.