全文获取类型
收费全文 | 738篇 |
免费 | 46篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 13篇 |
综合类 | 1篇 |
化学工业 | 209篇 |
金属工艺 | 16篇 |
机械仪表 | 17篇 |
建筑科学 | 13篇 |
能源动力 | 25篇 |
轻工业 | 91篇 |
水利工程 | 5篇 |
石油天然气 | 7篇 |
无线电 | 90篇 |
一般工业技术 | 125篇 |
冶金工业 | 59篇 |
原子能技术 | 9篇 |
自动化技术 | 107篇 |
出版年
2024年 | 2篇 |
2023年 | 14篇 |
2022年 | 35篇 |
2021年 | 44篇 |
2020年 | 42篇 |
2019年 | 39篇 |
2018年 | 34篇 |
2017年 | 32篇 |
2016年 | 29篇 |
2015年 | 35篇 |
2014年 | 41篇 |
2013年 | 54篇 |
2012年 | 53篇 |
2011年 | 42篇 |
2010年 | 26篇 |
2009年 | 22篇 |
2008年 | 26篇 |
2007年 | 25篇 |
2006年 | 15篇 |
2005年 | 15篇 |
2004年 | 12篇 |
2003年 | 9篇 |
2002年 | 13篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 11篇 |
1998年 | 9篇 |
1997年 | 9篇 |
1996年 | 10篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 12篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有787条查询结果,搜索用时 31 毫秒
61.
The morphological, thermal and pasting properties of starch separated from potatoes of three varieties (Kufri Chandramukhi, Kufri Jyoti and Kufri Chipsona-2), treated either with CIPC (isopropyl N-(3 chlorophenyl) carbamate) or γ-irradiation (Co60, 0.1 and 0.5 kGy) and subsequently stored at 8, 12 and 16 °C for 90 days, were studied. Scanning electron microscopy (SEM) showed the presence of oval and irregular shaped starch granules with a diameter range of 15–16 μm. Mean granule size of starch separated from potatoes stored at 12 °C ranged from 18–25 μm and irradiation treatment resulted in an increase in the proportion of small size granules. The irradiation of potatoes with 0.5 kGy resulted in starch with significantly lower peak-, trough- and breakdown-viscosity as compared to starch from potatoes treated with either CIPC or 0.1 kGy irradiation. The irradiation of potatoes with 0.5 kGy caused a significant increase in setback and pasting temperature. Pasting temperature of starch was observed to vary with the storage temperature. Starch separated from potatoes stored at higher temperature showed lower pasting temperature and vice versa. The starch from potatoes stored at 8 °C showed higher peak-, trough- and breakdown-viscosity and lower setback. Peak viscosity increased and swelling volume decreased with increase in storage temperature. FTIR spectra showed that the starch from irradiated potatoes displayed a significant decrease in the intensity of the C–H stretch region between 2800 and 3000 cm−1, which was observed to be irradiation dose-dependent, and higher with 0.5 than 0.1 kGy. However, a slight broadening of O–H stretch (3000–3600 cm−1) in starches from irradiated potatoes was observed. The spectral changes caused by γ-irradiation were apparent in the O–H stretch (3000–3600 cm−1), C–H stretch (2800–3000 cm−1) and bending mode of water (1600–1800 cm−1). 相似文献
62.
Chakraborty P. Misra A. Misra T. Rana S.S. 《Geoscience and Remote Sensing, IEEE Transactions on》2008,46(6):1768-1773
This paper departs from the popular usage of the Backus-Gilbert inversion (BGI) method as a tool for inversion of antenna temperature measurements in microwave radiometry. The BGI method is applied in this paper to enhance the information content of an existing set of oversampled brightness-temperature (TB) data. The purpose is to isolate the inversion process from its resolution enhancement counterpart. The advantage gained is that the resolution enhancement can be performed in a simplified way and in a different level of processing that starts with the scan-mode TB data product and simply requires with it the knowledge of the antenna gain pattern and the sensor's scan geometry. The technique is demonstrated with the 19.35-GHz Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) channel, which provides oversampled TB data. The radiometric resemblance of this channel with that of the 37 GHz and geocollocation of their TB footprints facilitate validation of the enhancement of features. The significance of oversampling the low-frequency (LF) radiometer channels is underscored in the process, which gives the authors the confidence to propose oversampling of the LF data for the forthcoming sensor Microwave Analysis and Detection of Rain and Atmospheric Structures (MADRAS) onboard the Megha_Tropiques mission, which is a joint ISRO-CNES collaboration (due for launch in 2009). 相似文献
63.
A simple and highly sensitive sensor based on edge-plane pyrolytic graphite electrode (EPPGE) coated with single-wall carbon nanotubes is proposed for diclofenac determination in nanomolar concentrations. The oxidation of diclofenac occurred in two well-defined peaks having peak potentials ∼439 and ∼854 mV at pH 7.2. The modified electrode showed excellent catalytic activity presenting much higher peak currents than those measured on a bare EPPGE. Under the optimum conditions, the calibration curve was linear in the concentration range 1 × 10−9-500 × 10−9 M and 25 × 10−9-1500 × 10−9 M for peaks I and II, respectively. The limit of detection for peaks I and II was found as 0.82 × 10−9 and 22.5 × 10−9 M, respectively. The developed sensor was applied for the determination of diclofenac in biological and pharmaceutical samples using square-wave voltammetry and the validation of results using high performance liquid chromatography showed excellent agreement. 相似文献
64.
Abdollah Karami Reem Shomal Rana Sabouni Sana Z. M. Murtaza Mehdi Ghommem 《加拿大化工杂志》2023,101(5):2660-2676
In this work, TiO2 and ZnO were incorporated successfully into a MIL-53(Al) metal–organic framework (MOF) to form nanocomposites via a facile post-modification technique. The hybrid MIL-53(Al)@TiO2 and MIL-53(Al)@ZnO were characterized by several characterization tests. The X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and field-emission scanning electron microscopy (FE-SEM) analyses showed evidence of the successful incorporation of TiO2 and ZnO within the MIL-53(Al) framework. The thermal gravimetric analysis (TGA) analysis demonstrated the excellent thermal stability of MIL-53(Al)@TiO2 and MIL-53(Al)@ZnO, while diffuse reflectance spectroscopy (DRS) determined the direct optical band gaps of MIL-53(Al)@ZnO and MIL-53(Al)@TiO2 to be 3.24 and 3.34 eV, respectively. The composites were also tested for the photocatalytic degradation of diclofenac (DCF) as a micropollutant. The DCF degradation efficiency of the photocatalysts was ranked in the following order: MIL-53(Al)@TiO2 > MIL-53(Al) > TiO2 > ZnO > MIL-53(Al)@ZnO. The incorporation of TiO2 enhanced the optical properties of MIL-53 (Al), which was confirmed with the superior photodegradation efficiency of MIL-53(Al)@TiO2 (>85% in 2 h) as compared to the pristine MIL-53(Al) (around 80% in 2 h). The improvement in the photodegradation of the hybrid-MOF is mostly associated with the possible dual function of the adsorption and photodegradation mechanisms. The reusability of MIL-53(Al) and its composites was inspected over 3 cycles of photodegradation experiments with DCF. The photocatalytic activity of MIL-53(Al)@TiO2 remained unchanged (>90%), while for MIL-53(Al) and MIL-53(Al)@ZnO a slight drop was observed over three cyclic degradation experiments. Fluorescence measurements revealed that the hydroxyl radical is an important reactive oxygen species produced by all the photocatalysts that aid in the photodegradation of DCF. Furthermore, the kinetic modelling of the photoreaction identified a second-order kinetics for all catalysts. Experiments with scavengers showed that hydroxyl radicals played a major role in the photocatalytic process, and it was found that only 2 h of treatment was sufficient to obtain a considerable chemical oxygen demand (COD) reduction of 58%. 相似文献
65.
Investigation on Sodium Benzoate Release from Poly(Butylene Adipate‐Co‐Terephthalate)/Organoclay/Sodium Benzoate Based Nanocomposite Film and Their Antimicrobial Activity
下载免费PDF全文
![点击此处可从《Journal of food science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dibyendu Mondal Biplab Bhowmick Dipanwita Maity Md. Masud R. Mollick Dipak Rana Vivek Rangarajan Ramkrishna Sen Dipankar Chattopadhyay 《Journal of food science》2015,80(3):E602-E609
Polymeric nanocomposites embedded with nontoxic antimicrobial agents have recently gained potential industrial significance, mainly for their applicability to preserve food quality and ensure safety. In this study, a poly(butylene adipate‐co‐terephthalate) (PBAT)/organoclay (CMMT) based nanocomposite film doped with sodium benzoate (SB) as antimicrobial agent was prepared by a solution mixing process. A homogenous dispersion of organoclay (cetyltrimethylammonium‐modified montmorillonite [CMMT]) in PBAT matrix was observed by X‐ray diffraction and transmission electron microscopy. PBAT/CMMT nanocomposite film showed higher barrier properties against water and methanol vapor compared to the PBAT film. The release of SB from PBAT and its nanocomposite film was measured and the relevant data were fitted to the Weibull model. The higher values of Weibull's shape factor and scale parameter as corroborated by experimental findings indicated faster rate of SB release from PBAT/CMMT/SB nanocomposite film, when compared to the pristine PBAT film. Bacterial inhibition studies were accomplished against 2 food pathogenic bacteria, Bacillus subtilis and Staphylococcus aureus, by determining the zone of inhibition and corresponding growth profiles. Both bacterial inhibition studies and growth profiles established that PBAT/CMMT/SB demonstrated better antimicrobial activity than PBAT/SB film. Therefore, PBAT/CMMT/SB nanocomposite film can be used for food packaging application as it showed good barrier properties and antimicrobial activity against food pathogenic bacteria. 相似文献
66.
67.
Rayisa Voytovych Rana Israel Noelia Calderon Fiqiri Hodaj Nicolas Eustathopoulos 《Journal of the European Ceramic Society》2012,32(14):3825-3835
The fundamental issues of the reaction at liquid Si/graphite interfaces between Si melting point (1412 °C) and 1600 °C are studied on the basis of results obtained with polycrystalline graphite concerning the growth kinetics of the interfacial reaction layer and the microstructure and morphology of this layer. Experiments were also performed using vitreous carbon substrates. Results are also reported for Si–Al alloys at 1000 °C. The elementary process controlling the growth kinetics is determined and a model is proposed to describe the different stages of the interfacial reaction. 相似文献
68.
Swati Ghosh Vishav Preet Singh Rana Vivekanand Kain Vivek Mittal S.K. Baveja 《Materials & Design》2011,32(7):3823-3831
Effect of residual stress generated during tube fabrication, roll expansion and machining of stainless steel on the stress corrosion cracking (SCC) susceptibility was studied by testing fabricated tubes, tube–tube sheet joint and heavily machined plate of austenitic stainless steel (SS) in boiling MgCl2. U bend samples of machined plate were exposed to acidified SO4 + Cl? environment at room temperature to study its ambient temperature SCC behavior. The results correlate the SCC behavior of the SS tubes and roll expanded joints to the nature and magnitude of residual stresses present. The study also highlights the distinct difference in ambient temperature SCC behavior of machined vs. nonmachined surfaces. 相似文献
69.
In present communication, we propose a modified resource allocation strategy, namely, hybrid connection algorithm, for achieving efficient restoration in WDM optical networks. The main theme of the algorithm is that, while attempting connection establishment, a wavelength is reserved in advance for providing resources for backup lightpaths. The analysis and the comparison of the proposed strategy with other existing strategies has been undertaken using metrics such as, restoration efficiency, number of wavelength links used by primary and backup lightpaths, and the percent link utilization. The proposed strategy provides 100% restoration efficiency and much better performance than the existing techniques. 相似文献
70.