全文获取类型
收费全文 | 9189篇 |
免费 | 744篇 |
国内免费 | 147篇 |
专业分类
电工技术 | 149篇 |
综合类 | 381篇 |
化学工业 | 4160篇 |
金属工艺 | 99篇 |
机械仪表 | 141篇 |
建筑科学 | 323篇 |
矿业工程 | 125篇 |
能源动力 | 329篇 |
轻工业 | 3217篇 |
水利工程 | 78篇 |
石油天然气 | 106篇 |
武器工业 | 15篇 |
无线电 | 61篇 |
一般工业技术 | 573篇 |
冶金工业 | 223篇 |
原子能技术 | 28篇 |
自动化技术 | 72篇 |
出版年
2024年 | 70篇 |
2023年 | 126篇 |
2022年 | 192篇 |
2021年 | 239篇 |
2020年 | 318篇 |
2019年 | 282篇 |
2018年 | 333篇 |
2017年 | 447篇 |
2016年 | 389篇 |
2015年 | 323篇 |
2014年 | 497篇 |
2013年 | 1564篇 |
2012年 | 524篇 |
2011年 | 559篇 |
2010年 | 355篇 |
2009年 | 347篇 |
2008年 | 319篇 |
2007年 | 411篇 |
2006年 | 445篇 |
2005年 | 349篇 |
2004年 | 306篇 |
2003年 | 256篇 |
2002年 | 220篇 |
2001年 | 227篇 |
2000年 | 165篇 |
1999年 | 154篇 |
1998年 | 130篇 |
1997年 | 120篇 |
1996年 | 81篇 |
1995年 | 72篇 |
1994年 | 46篇 |
1993年 | 49篇 |
1992年 | 38篇 |
1991年 | 21篇 |
1990年 | 24篇 |
1989年 | 12篇 |
1988年 | 14篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
D. Wiesenborn Z. Zbikowski H. Nguyen 《Journal of the American Oil Chemists' Society》1995,72(2):183-188
Extract of purple sunflower hulls is a potential red food colorant; however, suitable process conditions must still be identified.
Selected process variables were studied using bench-scale units to prepare, clarify, concentrate and spray dry extracts. Concentration
by evaporation at 32°C and addition of maltodextrin to 15% (wt/dry wt) prior to drying largely eliminated pigment degradation
during those steps. Relative to water extracts, extracts prepared with 5 to 15% ethanol in water generally yielded more pigment
with similar levels of degradation and loss during subsequent processing. Use of 5% ethanol/2% citric acid reduced yield by
about half relative to water, but gave a powder with a lower degradation index and wetting time. Percentage recovery of pigment
during concentration and drying was not greatly affected by solvent type or extraction temperature. 相似文献
62.
Carbon Aerogels as Electrode Material in Supercapacitors 总被引:5,自引:0,他引:5
U. Fischer R. Saliger V. Bock R. Petricevic J. Fricke 《Journal of Porous Materials》1997,4(4):281-285
Due to their large specific surface area and their high electrical conductivity carbon aerogels are promising materials for electrodes in electrochemical double-layer capacitors (supercapacitor). The carbon aerogels were made via pyrolysis of resorcinol formaldehyde aerogels. The latter were prepared by supercritical and subcritical drying as well. The important findings of our investigation were, that the highest capacities of 46 F/cm3 were measured for samples with a density of about 800 kg/m3 pyrolyzed at 800°C. Also it was shown that RF-gels with molar resorcinol/catalyst ratios 1000 or higher can be dried subcritically without cracking or significant shrinkage. Carbon aerogels derived from these RF-aerogels have a small mesopore surface area, however an especially large micropore area. They provide electrical capacities which are most suitable for their use in supercapacitors. 相似文献
63.
Hironori Minoshima 《Chemical engineering science》2006,61(6):2101-2102
Previously developed model for spray drying of slurry droplets with high solid content (Liang, 2001) was revised to describe correctly a boundary condition on the outer surface of droplet on basis of the rate of liquid evaporation. 相似文献
64.
65.
我国干燥技术和装备的研究及应用 总被引:4,自引:0,他引:4
介绍我国干燥设备的开发、研究和应用情况。情况表明:我国干燥技术有很大的进步,大批进口干燥器的时代已经结束。 相似文献
66.
主要阐述FP石膏材料、制芯工艺过程及烘干工艺,阐述了应用硅橡胶母模复制石膏芯表面光洁度高,尺寸精度较好,硫化轮胎的铸造成品率达99%以上。 相似文献
67.
Effect of Mode of Drying on Microstructure of Potato 总被引:2,自引:0,他引:2
Potato v. Irga was subjected to blanching, and thereafter was dried by convection, puff-drying, and freeze-drying. Microstructure of raw, blanched, and dried tissue was analyzed under the light microscope using computer image analysis. It was found that the tissue of the investigated variety is built up from cells much smaller than those described in literature for other cultivars. Blanching caused starch gelatinization and increase of cross-sectional area of cells. There was no evidence of broken cell walls. Convective drying resulted in cell shrinkage and some breaking of cell walls. It was estimated that some 12% of cells lost integrity during drying. Limited disintegration of the tissue caused by convective drying is attributed to small size of cells, large contact area, and high cohesive forces between cells. Puff-drying damaged the tissue much more than the convective drying. The most devastating to tissue microstructure was freeze-drying, probably freezing per se. 相似文献
68.
介绍了引起氯气干燥系统设备管道漏裂、堵塞、腐蚀的原因及其危害性,提出了包括设定合理的工艺参数,严格执行操作规程及改造更新设备管路等解决措施。 相似文献
69.
70.
Alysson Leandro Ribeiro Rattes 《Powder Technology》2007,171(1):7-14
This paper reports the preparation and characterization of sustained release sodium diclofenac microparticles by spray drying. Aqueous dispersions of ethyl cellulose (Surelease®) and Eudragit RS 30 D® were evaluated as controlled release polymers. The product properties (product moisture, size distribution, particle morphology, flow properties, total drug load, in-vitro dissolution studies, and encapsulating efficiency) were determined as a function of inlet temperature of the spray drying, the feed flow rate and composition of the microencapsulating formulation. In general, lower values of the product moisture content were observed at higher drying temperatures. The spray-dried product was composed mainly by rounded-shape and multi-size particles. The mean particle diameters of the Eudragit based microparticles tended to be slight bigger than the Surelease based microparticles. The spray dried microparticles showed delayed drug dissolution rates, sustaining the drug release for several hours. These findings confirm the feasibility of the spray drying for preparation of microparticles with sustained release properties. The physical and chemical properties of the microparticles can be changed by varying the spray drying parameters as well as the microencapsulating formulation. 相似文献