全文获取类型
收费全文 | 597篇 |
免费 | 32篇 |
国内免费 | 4篇 |
学科分类
工业技术 | 633篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 33篇 |
2021年 | 23篇 |
2020年 | 18篇 |
2019年 | 17篇 |
2018年 | 32篇 |
2017年 | 26篇 |
2016年 | 22篇 |
2015年 | 15篇 |
2014年 | 30篇 |
2013年 | 45篇 |
2012年 | 40篇 |
2011年 | 37篇 |
2010年 | 30篇 |
2009年 | 40篇 |
2008年 | 36篇 |
2007年 | 20篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 14篇 |
1995年 | 5篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1973年 | 1篇 |
排序方式: 共有633条查询结果,搜索用时 15 毫秒
11.
K. Sri Bala Kameswari Chitra Kalyanaraman S. Porselvam K. Thanasekaran 《Clean Technologies and Environmental Policy》2012,14(2):241-250
The inoculum to substrate (I/S) ratio is an important factor which influences the anaerobic digestion process. In this study, the effect of different I/S ratios on the performance of co-digestion of fleshings along with mixture of sludge generated during treatment of tannery
wastewater was investigated. The parameters studied were biogas generation, volatile solids reduction, volatile fatty acid
(VFA) production, and the stability of the digestion process based on VFA to alkalinity ratio was evaluated for various I/S ratios. Economical significance of I/S ratio as related to the volume of the anaerobic digester and the potential benefit of bio-energy generated are discussed
in detail. 相似文献
12.
Effect of ozonation and ultrasonication pretreatment processes on co-digestion of tannery solid wastes 总被引:1,自引:1,他引:0
K. Sri Bala Kameswari Chitra Kalyanaraman K. Thanasekaran 《Clean Technologies and Environmental Policy》2011,13(3):517-525
Studies were carried out by the application of ozonation and ultrasonication as pretreatment processes on primary and secondary
sludge generated during treatment of tannery wastewater to enhance the soluble chemical oxygen demand (SCOD). Further, co-digestion
(simultaneous digestion of two or more substrates) studies were carried out in batch reactors using the fleshings (a solid
waste generated during the processing of raw hides or skins into finished leather) along with the primary and the secondary
sludge wherein biogas generation was compared with and without pre-treated sludge using ozone and ultrasonication processes,
respectively. It was found that, application of pretreatment processes enhanced biogas generation by 45% in the case of ozone
pre-treated sludge and 53% by ultrasonication processes, respectively, in conjunction with the fleshings. However, considering
the optimum contact time required, application of ultrasonication as a pretreatment process was found to be the most appropriate
and viable process to enhance the SCOD. This pretreatment process has the potential for implementation in tanneries using
the shortest possible ultrasonication time to minimize energy cost when compared with ozonation time. 相似文献
13.
14.
Han Liuyang Zhang Saisai Zhang Bowen Zhang Bo Hari Bala Zhang Zhanying 《Journal of Porous Materials》2022,29(1):269-278
Journal of Porous Materials - Aimed at detecting methane (CH4) gas at low operating temperature, porous ZnO/SnO2 nanocomposites were constructed through a simple two-step method. Pure SnO2 with a... 相似文献
15.
Sanket A. Deshmukh Zheng Li Ganesh Kamath Kamlesh J. Suthar Subramanian K.R.S. Sankaranarayanan Derrick C. Mancini 《Polymer》2013,54(1):210-222
Solvation dynamics and conformational transformation in oligomers with varying degree of temperature sensitivity is studied using molecular dynamics (MD) simulations. Conformational transformation in three model systems namely poly(N-isopropylacrylamide) (PNIPAM), poly(acrylamide) (PAA), and poly(ethylene glycol) (PEG) are compared and contrasted to understand the origin of a coil-to-globule transformations across the lower critical solution temperature (LCST) in thermo-sensitive oligomers. PNIPAM, PAA, and PEG are water-soluble oligomers. However, for the temperature range used in these simulations, PNIPAM shows an LCST whereas PAA and PEG are non-thermo-sensitive. Oligomers of PNIPAM, PAA, and PEG consisting of 30 monomer units (30-mer) each were simulated at 5 °C (278 K) and 37 °C (310 K). Conformational transformations in the oligomers are evaluated using structural and dynamical correlation functions such as radius of gyration, radial distribution function, residence time probabilities and hydrogen-bonding life-times. Our simulations suggest that the solubility, solvation dynamics, and conformation of the oligomers are dictated by two factors: (a) the local structure of proximal water and (b) the diffusion and exchange kinetics of proximal water with bulk water. In thermo-sensitive oligomer such as PNIPAM, we find that the coil-to-globule transition is closely related to the local ordering and solvation dynamics of PNIPAM. We have identified stable configurations of proximal water molecules for an oligomer undergoing conformational transition. The slow diffusional properties of proximal water molecules near PNIPAM oligomers suggests that water forms a stable network near hydrophilic groups of PNIPAM as compared to the hydrophilic groups of PAA and PEG. Thermal perturbation of this solvated structure results in significant reduction in local ordering of water, which contributes to the globular collapse and the reduced solubility of PNIPAM above its LCST. On the other hand, non-thermo-sensitive oligomers such as PAA and PEG are characterized by much faster diffusion and exchange kinetics of proximal water at the two simulated temperatures compared to PNIPAM. This faster exchange kinetics helps in maintaining higher hydration level of the oligomers and is responsible for the apparent hydrophilic character and thereby the observed solubility at the two simulated temperatures. 相似文献
16.
S. L. Agrawal Markandey Singh Mridula Tripathi Mrigank Mauli Dwivedi Kamlesh Pandey 《Journal of Materials Science》2009,44(22):6060-6068
Present work deals with findings on dielectric relaxation behaviour and a.c. conduction in a SiO2-doped polymer nanocomposite electrolyte system, namely, [(100 − x)PEO + xSiO2]:yNH4SCN. The formation of nanocomposite has been ascertained by XRD measurements. The effect of salt and filler (SiO2) on conductivity response of PEO-based nanocomposite polymer electrolyte has been investigated by impedance spectroscopy.
The variation of dielectric permittivity, dielectric loss and modulus spectra with frequency and temperature was carried out
from impedance spectroscopy data. The a.c. conductivity seems to follow the universal power law. 相似文献
17.
Power plants are one of the major industries suffering from severe erosion–corrosion (E‐C) problems resulting in substantial losses. One way of tackling this problem is by the use of thermal spray coatings. In the current investigation a new emerging technique i.e. cold spray coating process was used to deposit Ni‐20Cr and Ni‐50Cr powder on SA 516 (grade 70) boiler steel. The bare as well as the coated steels were subjected to cyclic experimental studies, in the superheater zone of a coal fired boiler. Weight change, thickness loss, XRD, FE‐SEM/EDS and X‐ray mapping techniques were used to analyse the eroded‐corroded specimens. The uncoated steel showed weight gain after exposure in the actual boiler environment, whereas, for the coated steels there was initial weight loss followed by negligible weight change. Based upon thickness loss data the cold‐sprayed Ni‐50Cr coating was found to provide better E‐C resistance than the Ni‐20Cr coating. 相似文献
18.
We report the formation of a very smooth, continuous and homogeneous diamond-like carbon DLC thin coating over a bare stainless
steel surface without the need for a thin Si/Cr/Ni/Mo/W/TiN/TiC interfacial layer. As confirmed by the field-emission scanning
electron microscopy, good adhesion is achieved as characterized by (i) the formation of a smooth, continuous film with no
pores, (ii) a significant reduction of oxygen in the interfacial layer, and (iii) the development of rich carbon content at
the top surface. Thickness measurements by cross-sectional secondary-emission microscopy showed that the DLC coating is essentially
a 2-dimensional material. 相似文献
19.
Chander Shekhar Sharma Amanda Ates Poulson Joseph Kamlesh A. Soni M. Wes Schilling Aaron Kiess 《International Journal of Food Science & Technology》2013,48(7):1410-1415
The efficacy of lauric arginate (LAE) on Salmonella survivability in ground chicken containing 9.8% fat was determined under refrigerated storage. The effect of LAE treatments on total aerobes, pH and objective colour were also assessed in ground chicken. LAE was highly effective against Salmonella in 0.1% peptone with no detectable survivors following treatment with 200 ppm and 400 ppm of LAE. No difference existed (P > 0.05) in the growth of Salmonella and total aerobes after treatment with 200 and 400 ppm of LAE in ground chicken inoculated with a four strain mixture of Salmonella. At these concentrations, LAE did not exhibit any treatment effect on the pH and colour of ground chicken (P > 0.05). In conclusion, although LAE possesses strong inhibitory (P < 0.05) effect against Salmonella in suspension in 0.1% peptone water, no inhibitory (P > 0.05) effect on growth of Salmonella was observed in ground chicken at the currently approved levels of 200 ppm of LAE. 相似文献
20.
Mohammad Ismail Mohamed ElGelany Ismail Bala Muhammad 《Construction and Building Materials》2011,25(5):2358-2364
The residual compressive strength of concrete containing palm oil fuel ash (POFA) after exposure to elevated temperatures and subsequent cooling was investigated. Specimens from ordinary Portland cement (OPC) and POFA concrete mixes were prepared and subjected to various temperature levels. The POFA concrete contains 20% partial replacement of cement by weight and the temperature levels are; 100, 300, 500 and 800 °C. Two cooling systems which include cooling at room temperature by the natural breeze and water-spray were involved. Compressive strength test was conducted on control specimens as well as concrete specimens revived through the two cooling systems. Physical properties accompanying thermal degradations were also assessed. Residual performance as a ratio of residual strength to original strength was evaluated. The residual performance was found to be higher in POFA concrete than in the normal concrete. In addition, water-cooling was realized to aggravate strength reduction in both normal and POFA concretes when compared with air-cooling. High temperature and cooling system were also found to have great influence on physical properties, such as; mass loss, discolouration and crack patterns. 相似文献