全文获取类型
收费全文 | 4449篇 |
免费 | 287篇 |
国内免费 | 93篇 |
专业分类
电工技术 | 60篇 |
技术理论 | 1篇 |
综合类 | 165篇 |
化学工业 | 615篇 |
金属工艺 | 47篇 |
机械仪表 | 180篇 |
建筑科学 | 257篇 |
矿业工程 | 59篇 |
能源动力 | 195篇 |
轻工业 | 2084篇 |
水利工程 | 43篇 |
石油天然气 | 87篇 |
武器工业 | 12篇 |
无线电 | 185篇 |
一般工业技术 | 233篇 |
冶金工业 | 49篇 |
原子能技术 | 96篇 |
自动化技术 | 461篇 |
出版年
2024年 | 19篇 |
2023年 | 61篇 |
2022年 | 105篇 |
2021年 | 138篇 |
2020年 | 131篇 |
2019年 | 97篇 |
2018年 | 110篇 |
2017年 | 131篇 |
2016年 | 148篇 |
2015年 | 172篇 |
2014年 | 207篇 |
2013年 | 316篇 |
2012年 | 303篇 |
2011年 | 381篇 |
2010年 | 274篇 |
2009年 | 283篇 |
2008年 | 220篇 |
2007年 | 287篇 |
2006年 | 249篇 |
2005年 | 139篇 |
2004年 | 132篇 |
2003年 | 131篇 |
2002年 | 101篇 |
2001年 | 103篇 |
2000年 | 105篇 |
1999年 | 95篇 |
1998年 | 65篇 |
1997年 | 49篇 |
1996年 | 45篇 |
1995年 | 40篇 |
1994年 | 37篇 |
1993年 | 22篇 |
1992年 | 26篇 |
1991年 | 20篇 |
1990年 | 10篇 |
1989年 | 13篇 |
1988年 | 14篇 |
1987年 | 10篇 |
1986年 | 12篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有4829条查询结果,搜索用时 62 毫秒
961.
962.
GRACIELA W. PADUA 《Journal of food science》1993,58(3):603-604
Low-field proton NMR and high-frequency dielectric measurements were performed on sucrose-filled agar gels of 0 to 1.2g sucrose/g water and starch pastes of concentrations between 0.2 and lg starch/ g water. The dielectric constant decreased linearly with increasing concentration for both. The dielectric loss of sucrose-filled agar gels showed two regions, first increasing and then decreasing with concentration. The dielectric loss data for starch pastes showed a constant value close to that of pure water throughout the concentration range. Dielectric data were related to hydration models derived from proton NMR measurements. 相似文献
963.
Johnson Aimie Edosomwan 《Computers & Industrial Engineering》1986,11(1-4):298-302
Labor productivity and the rate of return on investment techniques have been used to justify the application of computer-aided manufacturing. These techniques are partial measures and do not consider the total cost of doing business. This paper presents a step-by-step procedure for assessing the impact of computer-aided manufacturing on total productivity. Two case studies are presented. The first case study deals with the comparison of the total and partial productivities of the manual and computer-aided method of manufacturing printed circuit boards. The second case shows a comparison of the productivities of two types of computer-aided method of assembling printed circuit boards. Both case studies were conducted for a period of ten weeks. Computer system design problems encountered during implementation are discussed as well as ways to correct these problems. 相似文献
964.
965.
TotaldoseradiationcharacteristicsofnchannelMOSFETsfabricatedusingFIPOStechnologyZhuShiYang,HuangYiPing,WuDongPing(Depart... 相似文献
966.
967.
Gelling Characteristics of Pectin From Sunflower Head Residues 总被引:1,自引:0,他引:1
Gelling properties of sunflower head pectin were studied using two instrumental methods: the standard sag method and the Instron textural profile method. For the Instron method, the jellies were formulated with 0-60% sugar content with various amounts of calcium chloride (30 to 90 mg/g pectin) at pHs 5.4 and 6.0. Sunflower pectin had a gel power of 110 compared to 100 for a citrus low-methoxyl pectin and 120 for an amidated low-methoxyl pectin. Sunflower pectin formed jellies under all experimental conditions. Sunflower pectin has a high potential for producing low-caloric foods, particularly when a near-neutral taste is required. 相似文献
968.
Xiao Huang N. L. Richards M. C. Chaturvedi 《Materials and Manufacturing Processes》2004,19(2):285-311
Electron beam welding was conducted on cast alloy 718 with varying grain sizes obtained using Microcast (MX™) and conventional cast (CC) techniques. The average value per section of Total Crack Length (Av. TCL) was measured on each cross section and used to represent the material's weldability. It was found for the first time that the grain size had a reduced effect on the weldability of cast alloys, relative to that reported in the literature for wrought alloys; i.e., increased grain size in the range of 90-3000 microns resulted in improved weldability. This was determined to be related to the probability of welds intersecting grain boundaries and causing grain boundary microfissuring. The conclusion from the experimental analysis is corroborated by the use of a Weibull-type analysis to evaluate the probability of a weld microfissure occurring relative to the grain size. As grain size increases, the probability of the weld intersecting the grains is reduced, and thus, the likelihood of microfissuring is reduced. With regard to a single crystal, there are no grain boundaries intercepting the weld (probability = 0), and thus, microfissuring related to constitutional liquation of primary carbides, or segregation of species to grain boundaries would not occur. 相似文献
969.
称量法测定高放废液总蒸残物,总氧化物和密度 总被引:1,自引:0,他引:1
建立了称量法以测定高放废液总蒸残物、总氧化物和密度。定量移取高放废液原始样品于古英盘中,小心转入微型马弗炉。先于≤100℃下加热除去湿成水。接着升温至180℃除去结晶水,再于700℃灼烧。分别称重并计算总蒸残物和总氧化物。方法精密度(RSD)优于3%。定量取高放废液原始样品于称量瓶中称量,计算高放废液密度。方法精密度优于1%。 相似文献
970.
采用阳极氧化法在纯钛表面制备出了TiO2纳米管阵列薄膜.以罗丹明B为目标降解物,20W紫外灯(λ =253.7 nm)作为光源,探讨了制备Au-TiO2纳米管阵列(Au-TNTs)的最佳工艺,并采用扫描电镜(SEM)、X射线衍射物相分析(XRD)、能谱分析(EDS)等对样品进行了表征.结果表明,以1g/L HAuC14+ 30 g/L H3BO3为沉积液,当沉积电压为2.5V、超声条件下电沉积时间为60 s时,可制得理想稳定的Au-TNTs;Au掺入量占薄膜质量的16.71%,Au的掺入并没有改变TiO2纳米管阵列的表面形貌及晶型,但却显著提高了TiO2纳米管阵列的光催化活性.将Au-TNTs用于制糖废水的光催化降解,结果发现:当光照时间为30 h、pH值为1时,Au-TNTs对制糖废水的光催化降解率可达89.59%,比TNTs高出80%.Au-TNTs对制糖废水的光催化降解过程符合一级动力学过程. 相似文献