全文获取类型
收费全文 | 14690篇 |
免费 | 1270篇 |
国内免费 | 285篇 |
专业分类
电工技术 | 197篇 |
综合类 | 1160篇 |
化学工业 | 6434篇 |
金属工艺 | 139篇 |
机械仪表 | 165篇 |
建筑科学 | 1932篇 |
矿业工程 | 255篇 |
能源动力 | 685篇 |
轻工业 | 3177篇 |
水利工程 | 250篇 |
石油天然气 | 365篇 |
武器工业 | 15篇 |
无线电 | 64篇 |
一般工业技术 | 711篇 |
冶金工业 | 521篇 |
原子能技术 | 52篇 |
自动化技术 | 123篇 |
出版年
2024年 | 50篇 |
2023年 | 178篇 |
2022年 | 301篇 |
2021年 | 360篇 |
2020年 | 434篇 |
2019年 | 391篇 |
2018年 | 416篇 |
2017年 | 567篇 |
2016年 | 557篇 |
2015年 | 476篇 |
2014年 | 812篇 |
2013年 | 1889篇 |
2012年 | 1021篇 |
2011年 | 1036篇 |
2010年 | 742篇 |
2009年 | 771篇 |
2008年 | 668篇 |
2007年 | 852篇 |
2006年 | 854篇 |
2005年 | 677篇 |
2004年 | 565篇 |
2003年 | 486篇 |
2002年 | 361篇 |
2001年 | 323篇 |
2000年 | 232篇 |
1999年 | 214篇 |
1998年 | 162篇 |
1997年 | 136篇 |
1996年 | 103篇 |
1995年 | 106篇 |
1994年 | 65篇 |
1993年 | 79篇 |
1992年 | 68篇 |
1991年 | 47篇 |
1990年 | 33篇 |
1989年 | 27篇 |
1988年 | 33篇 |
1987年 | 23篇 |
1986年 | 26篇 |
1985年 | 43篇 |
1984年 | 29篇 |
1983年 | 18篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 6篇 |
1951年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Manoj Karakoti Ritu Jangra Sandeep Pandey Pawan Singh Dhapola Sunil Dhali Suman Mahendia Pramod K Singh Nanda Gopal Sahoo 《International Journal of Applied Ceramic Technology》2020,17(4):1899-1908
This study deals with the utility of mini spray dryer process to improve the dispersibility, of graphene oxide(GO) and its application for high-performance supercapacitor. Initially, the neutral solution of GO was obtained using the modified Hummer's method. After this, the prepared GO solution was processed by mini spray dryer to obtain a more purified, lighter, and dispersed form of GO which is named as spray dryer processed GO (SPGO). The SPGO thus obtained showed excellent dispersibility behavior with various solvents, which is not found in case of conventional oven drying. Furthermore, utility of SPGO and its reduced form (r-SPGO) for supercapacitor applications have been investigated. Results obtained from the cyclic voltammetry(CV) analysis, impedance, and charge-discharge behavior of supercapacitor fabricated using r-SPGO shows enhanced features. Therefore, the simple spray dried GO and its reduced form, that is, r-SPGO can be utilized as a potential candidate for the supercapacitor application. Herein, as synthesized SPGO exhibited the specific capacitance of 12.07 and 37.6 F/g with PVA-H3PO4 and 1 mol/L H3PO4, respectively, at a scan rate of 5 mV/s. On the other hand, reduced form of SPGO, that is, r-SPGO showed the specific capacitance of 27.16 and 230 F/g with PVA-H3PO4 and 1 mol/L H3PO4, respectively. 相似文献
2.
3.
Riham Gharib Jouda Mediouni Ben Jema Catherine Charcosset Sophie Fourmentin Hlne Greige‐Gerges 《European Journal of Lipid Science and Technology》2020,122(5)
Eucalyptol (Euc) is a natural monoterpene with insecticide effects. Being highly volatile and sensitive to ambient conditions, its encapsulation would enlarge its application. Euc‐loaded conventional liposomes (CL), cyclodextrin/drug inclusion complex, and drug‐in‐cyclodextrin‐in‐liposomes (DCL) are prepared to protect Euc from degradation, reduce its evaporation, and provide its controlled release. The liposomal suspension is freeze‐dried using hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) as cryoprotectant. The liposomes are characterized before and after freeze‐drying. The effect of Euc on the fluidity of liposomal membrane is also examined. A release study of Euc from delivery systems, in powder and reconstituted forms, is performed by multiple head extraction at 60 °C after 6 months of storage at 4 °C. CL and DCL suspensions are homogeneous, show nanometric vesicles size, spherical shape, and negative surface charge before and after freeze‐drying. Moreover, HP‐β‐CD does not affect the fluidity of liposomes. CL formulations present a weak encapsulation for Euc. The loading capacity of eucalyptol in DCL is 38 times higher than that in CL formulation. In addition, freeze‐dried DCL and HP‐β‐CD/Euc inclusion complex show a higher retention of eucalyptol than CL delivery system. Both carrier systems HP‐β‐CD/Euc and Euc‐loaded DCL decrease Euc evaporation and improve its retention. Practical Applications: Eucalyptol is a natural insecticide. It is highly volatile and poorly soluble in water. To enlarge its application, its encapsulation in three delivery systems (conventional liposomes, cyclodextrin/drug inclusion complex, combined system composed of cyclodextrin inclusion complex and liposome) is studied. In this paper it is proved that cyclodextrin/eucalyptol inclusion complex and eucalyptol‐in‐cyclodextrin‐in‐liposome are effective delivery systems for encalyptol encapsulation, retention, and release. 相似文献
4.
5.
Harshita Gogoi V. Nirosha Anjali Jayakumar Keerthana Prabhu Meghna Maitra 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2018,40(1):39-44
In the present study, pre-treated paper mill sludge (PMS) was evaluated extensively as a substrate for production of acetone-butanol-ethanol using Clostridium sporogenes NCIM 2337. The PMS was subjected to three types of pre-treatment methods namely alkali, mechanical, and thermal treatment and was analyzed by SEM. The pre-treatment of PMS by alkali was observed to be more effective over the other pre-treatment methods. The alkali pre-treated sludge was then made to undergo fermentation, which showed the conventional process of acidogenesis followed by solventogenesis. The acetone, butanol, and ethanol concentration for 15% alkali pre-treated PMS was estimated to be maximum. 相似文献
6.
Experimental and simulation studies on the migration characteristics of heavy metals during the incineration of OS were conducted with a tube furnace reactor and thermodynamic equilibrium calculation software FactSage, respectively. The results showed that when the incineration temperature increased from 800°C to 1100°C, the release rates of heavy metals such as Cr, Pb, Cu, Zn and Ni increased gradually and reached the maximum at 1000°C. When the excess air ratio increased from 1.0 to 1.4, the release rates of heavy metals such as Cr, Pb, Cu, Zn and Ni first decreased and then became steady. The content of gaseous hydroxide of Cr and gaseous chlorides of Pb and Cu increased while the chemical forms of Zn and Ni did not change obviously with the increase of combustion temperature or excess air ratio. 相似文献
7.
《Advanced Powder Technology》2020,31(1):287-299
The parameters governing the crystallisation of paracetamol using various conventional techniques has been extensively studied, however the factors influencing the drug crystallisation using spray drying is not as well understood. The aim of this work was to investigate the crystallisation of an active pharmaceutical ingredient through evaporative crystallisation using a spray dryer to study the physicochemical properties of the drug and to use semi-empirical equations to gain insight into the morphology and particle size of the dried powder. Paracetamol solutions were spray dried at various inlet temperatures ranging from 60 °C to 120 °C and also from a series of inlet feed solvent compositions ranging from 50/50% v/v ethanol/water to 100% ethanol and solid-state characterisation was done. The size and morphology of the dried materials were altered with a change in spray drying parameters, with an increase in inlet temperature leading to an increase in particle Sauter mean diameter (from 3.0 to 4.4 µm) and a decrease in the particle size with an increase in ethanol concentration in the feed (from 4.6 to 4.4 µm) as a result of changes in particle density and atomised droplet size. The morphology of the dried particles consisted of agglomerates of individual crystallites bound together into larger semi-spherical agglomerates with a higher tendency for particles having crystalline ridges to form at higher ethanol concentrations of the feed. 相似文献
8.
污泥生物炭中氮硫元素含量高,其氮硫行为和环境效应对全球气候变化的影响不容忽视。以往的研究中,研究者往往以富碳生物炭作为主要研究对象,关注碳对全球气候变化的行为和功效,而对氮硫元素的作用关注不够。本文从原始污泥基本性质到其热解过程,再到生物炭的老化,逐步对污泥生物炭整个生命周期内氮硫的行为及其环境效应研究进行综述,并对未来应注重开展的研究方向进行展望,为生物炭中氮硫元素固定、释放及与之关联的环境效应和温室气体排放控制研究提供理论基础。分析表明,污泥中氮元素含量普遍高于硫元素,且热解过程中氮比硫更容易转移至气相产物。氮硫元素随热解温度的增加,在三相产物中的分配都是炭中持续减少,油中先增后减,气中一直增加。高温(>800℃)条件下,气相中的氮含量高于固相,而硫元素则仍然主要存在于固相中。污泥生物炭老化及其环境效应研究表明,污泥生物炭氮硫元素与土壤的相互作用及其温室效应问题在今后的研究中应引起重视。 相似文献
9.
10.