全文获取类型
收费全文 | 4757篇 |
免费 | 275篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 59篇 |
综合类 | 8篇 |
化学工业 | 947篇 |
金属工艺 | 55篇 |
机械仪表 | 75篇 |
建筑科学 | 178篇 |
矿业工程 | 5篇 |
能源动力 | 162篇 |
轻工业 | 328篇 |
水利工程 | 54篇 |
石油天然气 | 35篇 |
无线电 | 392篇 |
一般工业技术 | 1196篇 |
冶金工业 | 597篇 |
原子能技术 | 13篇 |
自动化技术 | 936篇 |
出版年
2024年 | 13篇 |
2023年 | 60篇 |
2022年 | 96篇 |
2021年 | 140篇 |
2020年 | 115篇 |
2019年 | 122篇 |
2018年 | 126篇 |
2017年 | 139篇 |
2016年 | 162篇 |
2015年 | 134篇 |
2014年 | 188篇 |
2013年 | 335篇 |
2012年 | 309篇 |
2011年 | 388篇 |
2010年 | 295篇 |
2009年 | 281篇 |
2008年 | 308篇 |
2007年 | 246篇 |
2006年 | 217篇 |
2005年 | 188篇 |
2004年 | 152篇 |
2003年 | 134篇 |
2002年 | 128篇 |
2001年 | 66篇 |
2000年 | 61篇 |
1999年 | 60篇 |
1998年 | 50篇 |
1997年 | 45篇 |
1996年 | 50篇 |
1995年 | 44篇 |
1994年 | 40篇 |
1993年 | 36篇 |
1992年 | 39篇 |
1991年 | 20篇 |
1990年 | 27篇 |
1989年 | 14篇 |
1988年 | 14篇 |
1987年 | 29篇 |
1986年 | 17篇 |
1985年 | 29篇 |
1984年 | 13篇 |
1983年 | 6篇 |
1982年 | 13篇 |
1981年 | 20篇 |
1980年 | 6篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1975年 | 7篇 |
1974年 | 6篇 |
1973年 | 6篇 |
排序方式: 共有5040条查询结果,搜索用时 15 毫秒
91.
Jonathan Sampath Franklyne Swati Iyer Andrew Ebenazer Amitava Mukherjee Natarajan Chandrasekaran 《International Journal of Food Science & Technology》2019,54(9):2802-2810
Many human acid tolerant bacterial and fungal pathogens can be transmitted through the consumption of the contaminated fruit juices. We aim to formulate essential oil nanoemulsions (basil, black seed, turmeric, clove & cinnamon), determine their ability to clear contamination by food borne bacterial pathogens from fruit juices. The antibacterial activity of the optimised formulations was tested in the fruit juices against bacterial pathogens causing gastrointestinal tract infections. The minimum bactericidal concentration (MBC) of clove emulsions ranged from 15.6 to 25 μL mL−1. Cinnamon oil emulsion had an MBC ranging between 15 and 31 μL mL−1. At MBC, cinnamon oil emulsions caused a 6log10 decrease in viable counts by 8 h and maintained the sterility of fruit juices for 7 days at ambient temperature. Thus, clove and cinnamon microemulsions can be used as juice additives to control food borne bacterial pathogens and maintain the bacterial sterility of fruit juices. 相似文献
92.
Pourrezaei P Drzewicz P Wang Y Gamal El-Din M Perez-Estrada LA Martin JW Anderson J Wiseman S Liber K Giesy JP 《Environmental science & technology》2011,45(19):8452-8459
Coagulation/flocculation (CF) by use of alum and cationic polymer polyDADMAC, was performed as a pretreatment for remediation of oil sands process-affected water (OSPW). Various factors were investigated and the process was optimized to improve efficiency of removal of organic carbon and turbidity. Destabilization of the particles occurred through charge neutralization by adsorption of hydroxide precipitates. Scanning electron microscope images revealed that the resultant flocs were compact. The CF process significantly reduced concentrations of naphthenic acids (NAs) and oxidized NAs by 37 and 86%, respectively, demonstrating the applicability of CF pretreatment to remove a persistent and toxic organic fraction from OSPW. Concentrations of vanadium and barium were decreased by 67-78% and 42-63%, respectively. Analysis of surface functional groups on flocs also confirmed the removal of the NAs compounds. Flocculation with cationic polymer compared to alum, caused toxicity toward the benthic invertebrate, Chironoums dilutus, thus application of the polymer should be limited. 相似文献
93.
The depuration of gas-phase polychlorinated biphenyls (PCBs) from a slow-growing evergreen shrub, Skimmia japonica Thunb., was studied to investigate the reversibility of uptake and the compartmentalization of PCB congeners within leaves with respect to air-plant exchange processes. Depuration of PCBs was monitored over periods of hours, days, and weeks. Equilibrium had not been attained between air and leaves during the uptake phase after many weeks. Depuration followed two-phase clearance kinetics, with phase 1 occurring over the order of hours and phase 2 continuing slowly over weeks. In phase 1, a substantial part (ca. 40%) of the PCB burden that the plants had accumulated over weeks was lost in 2-3 h. This observation is further evidence for the close dynamic coupling of air and vegetation compartments. In the second phase, very slow depuration over 28 d only removed a further approximately 25% of the accumulated PCB burden. Depuration rates in phase 2 varied between compounds and were not influenced by growth dilution. Depuration rates for both phases were not correlated with KOA, indicating that plant-air mass transfer coefficients were proportional to plant-air partition coefficients and, therefore, probably dominated by the plant-side resistance to diffusion. Photolysis and metabolism are unlikely to have influenced the rates of congener disappearance. Pathways into the leaf and possible storage locations within the plant are discussed with respect to the observed differences between uptake and clearance rates. Uptake and depuration are not mirror image processes, with a fraction of accumulated PCBs effectively stored in the leaves. This has important implications for terrestrial food chain transfer and global cycling with leaf concentrations remaining elevated long after a contamination event. 相似文献
94.
95.
Liezhou Zhong Hayder Ali Zhongxiang Fang Mark L. Wahlqvist Jonathan M. Hodgson Stuart K. Johnson 《International Journal of Food Science & Technology》2020,55(4):1816-1824
The high proportion of seed coat of legume lupins results in big milling lose during kernel flour production, though the seed coat could be value-added as human food. The physicochemical and nutritional properties and antioxidant capacities of seed coats of six Australian sweet lupin cultivars grown at two locations were evaluated. Results showed that genotype, environment and their interaction were significant for seed coat percentage, proximate composition, dietary fibre content, polyphenols and antioxidant capacities. Strong correlations between seed coat lightness and polyphenol content were found. A comparison using multivariate analysis of the seed coat properties showed clear separation based on growing sites. This study indicates the enormous potential of Australian sweet lupin seed coat as an ‘antioxidant dietary fibre’ food source. The results could also benefit to breed varieties with desirable levels of nutrients and phytochemicals. 相似文献
96.
The aim of this study was to evaluate the suitability of Methylene Blue (MB) and Vitamin B12 (Vit-B12) as water soluble inner aqueous phase (W1) markers for measuring the encapsulation efficiency and stability of water-in-oil-in-water (W1/O/W2) double emulsions stabilized by sodium caseinate (NaCN). The encapsulation efficiency and stability were determined by centrifugation of the double emulsion to separate the cream phase (W1/O) and the outer aqueous phase (W2) and measuring the concentration of marker in W2 by absorbance spectrophotometry. To validate this method the marker concentration measurable and the stability of the marker in W2 were measured. Both markers could be accurately measured in W2 and there was no change in the concentration of marker on storage of a W2 solution for 7 days at 45 °C. The recovery yields of MB and Vit-B12 in the recovered W2 of an oil-in-water (O/W2) emulsion, determined using the procedure normally used for measuring encapsulation efficiency and stability, were 78% and 99%, respectively, and 52 and 100%, respectively. Double emulsions had encapsulation efficiency of 61.9 ± 21.4% and 16.6 ± 1.1% and encapsulation stability of 62.0 ± 22.6% and 10.7 ± 0.7% for MB and Vit-B12, respectively. Recovery yield and encapsulation efficiency/stability data for MB indicate that it is not a suitable marker for measuring the encapsulation properties of NaCN stabilized double emulsions while similar data for Vit-B12 indicate that it is a suitable marker for studying the encapsulation properties of double emulsions stabilized with NaCN. Methods used in other studies to measure encapsulation properties of double emulsions are discussed in light of the results obtained in this study. 相似文献
97.
Jonathan Lesser 《Natural Gas \u0026amp; Electricity》2016,32(9):1-6
No other environmental issue today is the subject of more discussion, debate, and media coverage than human-induced climate change, which is supposedly caused by increasing emissions of carbon dioxide (CO2) from the combustion of fossil fuels. These debates cover everything from basic questions of physical measurement—How has the earth's climate changed over time? How may the climate change in the future because of increased CO2 concentrations in the atmosphere?—to debates over how increased CO2 emissions will affect the economic well-being of future generations. 相似文献
98.
Impact of the Cd2+ treatment on the electrical properties of Cu2ZnSnSe4 and Cu(In,Ga)Se2 solar cells
Khaled Ben Messaoud Marie Buffire Guy Brammertz Hossam ElAnzeery Souhaib Oueslati Jonathan Hamon Bas J. Kniknie Marc Meuris Mosbah Amlouk Jef Poortmans 《Progress in Photovoltaics: Research and Applications》2015,23(11):1608-1620
The present contribution aims at determining the impact of modifying the properties of the absorber/buffer layer interface on the electrical performance of Cu2ZnSnSe4 (CZTSe) thin‐film solar cells, by using a Cd2+ partial electrolyte (Cd PE) treatment of the absorber before the buffer layer deposition. In this work, CZTSe/CdS solar cells with and without Cd PE treatment were compared with their respective Cu(In,Ga)Se2 (CIGSe)/CdS references. The Cd PE treatment was performed in a chemical bath for 7 min at 70 °C using a basic solution of cadmium acetate. X‐ray photoemission spectroscopy measurements have revealed the presence of Cd at the absorber surface after the treatment. The solar cells were characterized using current density–voltage (J–V), external quantum efficiency, and drive‐level capacitance profiling measurements. For the CZTSe‐based devices, the fill factor increased from 57.7% to 64.0% when using the Cd PE treatment, leading to the improvement of the efficiency (η) from 8.3% to 9.0% for the best solar cells. Similar observations were made on the CIGSe solar cell reference. This effect comes from a considerable reduction of the series resistance (RS) of the dark and light J–V, as determined using the one‐diode model. The crossover effect between dark and light J–V curves is also significantly reduced by Cd PE treatment. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
99.
Frank Greenway Brian Loveridge Richard M. Grimes Tori R. Tucker Michael Alexander Scott A. Hepford Justin Fontenot Candi Nobles-James Carol Wilson Adam M. Starr Mohammed Abdelsaid Stanley T. Lewis Jonathan R. T. Lakey 《International journal of molecular sciences》2022,23(3)
Prevalence of type 2 diabetes increased from 2.5% of the US population in 1990 to 10.5% in 2018. This creates a major public health problem, due to increases in long-term complications of diabetes, including neuropathy, retinopathy, nephropathy, skin ulcers, amputations, and atherosclerotic cardiovascular disease. In this review, we evaluated the scientific basis that supports the use of physiologic insulin resensitization. Insulin resistance is the primary cause of type 2 diabetes. Insulin resistance leads to increasing insulin secretion, leading to beta-cell exhaustion or burnout. This triggers a cascade leading to islet cell destruction and the long-term complications of type 2 diabetes. Concurrent with insulin resistance, the regular bursts of insulin from the pancreas become irregular. This has been treated by the precise administration of insulin more physiologically. There is consistent evidence that this treatment modality can reverse the diabetes-associated complications of neuropathy, diabetic ulcers, nephropathy, and retinopathy, and that it lowers HbA1c. In conclusion, physiologic insulin resensitization has a persuasive scientific basis, significant treatment potential, and likely cost benefits. 相似文献
100.
Peter T.Cummings Philippe M.Fauchet Michael Goldfarb Martha W.M.Jones Maithilee Kunda Jonathan B.Perlin Nilanjan Sarkar Keivan G.Stassun Zachary E.Warren Karl E.Zelik 《工程(英文)》2021,7(2):141-143,中插10-中插13
1. Background
The use of engineering tools, design, research, and thinking to create environments and capabilities whereby individuals who are currently under-e... 相似文献