首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5174篇
  免费   273篇
  国内免费   449篇
工业技术   5896篇
  2024年   9篇
  2023年   74篇
  2022年   100篇
  2021年   151篇
  2020年   143篇
  2019年   141篇
  2018年   172篇
  2017年   221篇
  2016年   212篇
  2015年   180篇
  2014年   312篇
  2013年   346篇
  2012年   397篇
  2011年   588篇
  2010年   375篇
  2009年   442篇
  2008年   371篇
  2007年   391篇
  2006年   321篇
  2005年   194篇
  2004年   170篇
  2003年   130篇
  2002年   79篇
  2001年   59篇
  2000年   80篇
  1999年   49篇
  1998年   42篇
  1997年   32篇
  1996年   25篇
  1995年   18篇
  1994年   20篇
  1993年   16篇
  1992年   11篇
  1991年   13篇
  1990年   3篇
  1989年   3篇
  1988年   2篇
  1987年   1篇
  1985年   1篇
  1984年   1篇
  1976年   1篇
排序方式: 共有5896条查询结果,搜索用时 171 毫秒
81.
采用不同条件电化学沉积法在氧化铟锡(IT O )导电玻璃基底上自组装生长了一维ZnO阵列。利用X射线衍射仪(XRD)和场发射扫描电镜(FESEM )对其结构和形貌分别进行表征。结果表明,以种晶预生长时间为40 s的样品为衬底,Zn2+浓度为0.005 mol/L ,CTAB浓度为0.005 mol/L ,HMT浓度为0.01 mol/L ,沉积时间为10 min ,沉积电位为0.90 V条件下,能够制备出高度取向且致密的一维氧化锌阵列。  相似文献   
82.
利用静电纺丝和原子层沉积(ALD)方法制备了ZnFe2O4/ZnO纳米复合纤维并对其进行退火处理。利用扫描电子显微镜、X射线衍射仪、光致发光、紫外-可见分光光度计对其进行了性质的研究。结果表明,制备样品为一维核壳结构的纳米复合纤维,ZnO壳层由于高温退火的原因结晶度提高,ZnFe2O4纳米纤维与ZnO薄膜间的表面化学键连结起来并成功复合,降低了ZnO自由载流子的重结合几率,实现了光生载流子的大程度分离。并且直观的比较了不同催化剂的降解性能。  相似文献   
83.
1 Introduction Recently, demands for high product performance products have necessitated a precise control of ZnO particle properties for applications such as electrode of solar cells and photocatalysts. Much attention is given to the high chemical reacti…  相似文献   
84.
Spoke-like ZnO nanoneedles have been successfully synthesized at the ambient pressure through thermally oxidizing Zn powders containing Au nanoparticles. X-ray diffraction analysis indicates that the ZnO nanoneedles have a hexagonal wurtzite structure of the crystalline ZnO. The morphology of the products was examined by FESEM. The photoluminescenee(PL) spectrum under 325 nm exhibits both an UV emission and a green emission. It is interesting to note that the heating rate plays a key role in the synthesis of ZnO nanoneedles. Based on this discovery we propose to explain the special growth behavior as novel mechanism that a large temperature gradient and Au nanoparticles simultaneously result in the spoke-like ZnO nanoneedles growth.  相似文献   
85.
ZnO thin films were deposited on Si(111) substrates through a radio frequency (rf) magnetron sputtering system. Then the samples were annealed at different temperatures in air ambience and ammonia ambience respectively. The structure and composition of the ZnO films were studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The morphology of the samples was studied by scanning electron microscopy (SEM). Measured results show that ZnO films with hexagonal wurtzite structure were grown on Si(111) substrates when annealed in the two ambiences. The volatilization process of ZnO in the ammonia ambience at high temperature was discussed and the mechanism of the reaction was analyzed.  相似文献   
86.
ZnO thin films on Si(111) substrate were deposited by laser ablation of Zn target in oxygen reactive atmosphere, Nd-YAG laser with wavelength of 1 064 nm was used as laser source. XRD and FESEM microscopy were applied to characterize the structure and surface morphology of the deposited ZnO films. The optical properties of the ZnO thin films were characterized by photoluminescence. The UV and deep level (yellow-green) light were observed from the films. The UV light is the intrinsic property and deep level light is attributed to the existence of antisite defects (Ozn). The intensity of UV and deep level light depends strongly on the surface morphology and is explained by the surface roughness of ZnO film. A strongly UV emission can be obtained from ZnO film with surface roughness in nanometer range.  相似文献   
87.
通过XRD、TEM测试研究了自制ZnO/Ag纳米复合材料的结构和形貌,通过UV检测确定了以该纳米复合材料为光催化剂,在不同条件下对甲基橙的光催化降解率。结果表明:与空气煅烧相比,真空煅烧所得纳米复合材料的光催化降解效果更好,且光催化降解率随纳米复合材料用量增加而增大:甲基橙溶液的pH在5左右时,光催化降解率最高:H2O2浓度为0.9g/L时,光催化降解率可达100%。  相似文献   
88.
ZnO films for electronic applications were deposited by radio-frequency (rf) sputtering onto various metal bottom electrodes (Pt/Ti, W, Ni) to investigate such structural properties as crystallinity and surface morphology. The crystallinity, surface morphology and composition of the as-deposited films were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Rutherford back-scattering spectrometry (RBS), respectively. The preferred orientation and surface morphologies were strongly influenced by the type of bottom electrodes. The ZnO films with (200) texturing deposited on Pt/Ti/SiO2/Si showed a smoother and smaller grain size than those deposited on W and Ni. The ZnO films on Pt and W electrodes exhibited compressive residual stress. This article is based on a presentation made in the 2002 Korea-US symposium on the “Phase Transformations of Nano-Materials”, organized as a special program of the 2002 Annual Meeting of the Korean Institute of Metals and Materials, held at Yonsei University, Seoul, Korea on October 25–26, 2002.  相似文献   
89.
Free-standing diamond films were prepared by hot filament chemical vapor deposition (HFCVD) method under different conditions. Inter-digital transducers (IDTs) were formed on the nucleation sides of free-standing diamond films by photolithography technique. Then piezoelectric ZnO films were deposited by radio-frequency(RF) reactive magnetron sputtering to obtain the ZnO/diamond film structures. Surface morphologies of the nucleation sides and the IDTs were characterized by means of scanning electron microscopy (SEM), atomic force microscope (AFM) and optical microscopy. The results indicate that the surfaces of nucleation sides are very smooth and the IDTs are of high quality without discontinuity and short circuit phenomenon. Raman spectra show the sharp diamond feature peak at about 1 334 cmI and the small amount of non-diamond carbon in the nucleation side. X-ray diffraction (XRD) patterns of the structure of ZnO/diamond films show a strong diffraction peak of ZnO (002), which indicates that as-sputtered ZnO films are highly c-axis oriented.  相似文献   
90.
通过正交实验,研究了反应温度、反应时间、反应物配比对ZnO/Ag纳米复合抗菌剂合成产率的影响规律。获得了高产率合成ZnO/Ag纳米复合抗菌剂的优选工艺条件:反应温度为10~25℃,ZnSO4与NH4HCO3的摩尔比为1:2-2.5,ZnSO4与NH4HCO3的反应时间为2.5~3h,AgNO3与NH4HCO3的摩尔比为1:1.5~2,反应时间为0.5h,ZnO/Ag的产率超过98%。XRD、TEM和SAED结果表明:ZnO/Ag纳米复合抗菌剂为具有纤锌矿结构的ZnO和立方结构的Ag组成。粒径为15~25nm,分散性较好。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号