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61.
Hexanuclear oxo titanium(IV) isopropoxide carboxylates, of the general formula [Ti6O6(OPri)6(O2CR)6] (R = But (1), CH2But (2)) and [Ti6O6(OPri)6(O2CC(CH3)2Et)6] · 0.5(C7H8) (3), have been synthesized as polycrystalline powders in order to study their thermal properties and usability as TiO2 CVD precursors. Analysis of thermogravimetric and variable temperature (VT-IR) data shows that the thermal stability of the synthesized complexes decreases as follows 3 > 2 > 1. The composition of the vapors formed during the thermolysis of 1–3 were qualitatively analysed with VT-IR methods and mass spectrometry (MS-EI). According to obtained results, the decomposition of 1 and 2 proceeds with a partial decomposition and the formation of a volatile and stable titanium species, sufficient for their transport in vapors. The formation of volatile titanium-containing derivatives is an important factor that decides the application of 1 and 2 as precursors in CVD experiments. The high stability of 3 causes the thermal decomposition of this complex to be observed just above 573 K, and volatile titanium-containing derivatives were not detected in vapors. These results indicate that 3 could not be used as a precursor in CVD processes. 相似文献
62.
采用单源化学气相沉积(SSCVD)法,在石英衬底上以Au为缓冲层,Zn4(OH)2(O2CCH3)6.2H2O为固相源制备ZnO薄膜。SEM和XRD测试ZnO薄膜的微结构,结果表明:相对于SiO2衬底上生长的ZnO薄膜,Au/SiO2衬底上生长的ZnO薄膜具有较好的结晶质量和表面平整度;对制备ZnO薄膜的衬底温度进行了工艺优化,结果表明:500℃时制备的ZnO薄膜颗粒大小均匀,结晶质量较好;通过荧光光谱仪对Au/SiO2衬底上的ZnO薄膜进行光致发光(PL)谱测试,ZnO薄膜在400nm出现紫光发射峰,而没有出现与缺陷相关的深能级发射峰,表明ZnO薄膜具有较好的结晶质量。 相似文献
63.
《Organic Electronics》2014,15(8):1717-1723
We have investigated the growth behavior and water vapor permeation barrier properties of cyclic chemical vapor deposition (C-CVD)-grown 10-nm-thick single layer of Al2O3. Al2O3 layers grown by C-CVD showed a high density of 3.298 g/cm3 and were amorphous without grain boundaries. A deposition rate of 0.46 nm/cycle was obtained. The C-CVD system was self-limiting, as in the case of atomic layer deposition, which enables precise control of the thickness of the Al2O3 layer. A water vapor transmission rate of 1.51 × 10−5 (g/m2)/day was obtained from a Ca degradation test performed at 85 °C and 85% relative humidity. Moreover, the performance of organic light-emitting diodes, passivated by a C-CVD-grown 10-nm-thick Al2O3 single layer, was not affected after 24,000 h of turn-on time; this is strong evidence that C-CVD-grown Al2O3 layers effectively prevent water vapor from diffusing into the active organic layer. 相似文献
64.
Carbon Nanotubes Grown on Sepiolite as Catalyst Carrier 总被引:2,自引:0,他引:2
Multi-walled carbon nanotubes were synthesized by the catalytic decomposition of acetylene at 750℃ over sepiolite powder,which was treated with aqueous cobalt nitrate. It is expected that the composite with high specific area will have high capacity of hydrogen storage. 相似文献
65.
66.
以Zn4(OH)2(O2CCH3)6·2H2O为单一固相有机源,采用单源化学气相沉积法(Single sour cechem icalvapor deposition,SSCVD)在Si(100)衬底上制备ZnO薄膜,用X射线衍射(XRD)、原子力显微镜(AFM)分析ZnO薄膜样品的晶体结构和微观形貌,并用X射线光电子能谱(XPS)对薄膜的锌氧化学计量比进行了分析。研究结果表明:在非平衡条件下所得到的ZnO薄膜沿a-b轴取向生长,基片温度对ZnO薄膜生长过程影响较大,随着基片温度的升高,薄膜呈现c轴生长趋势;晶粒成柱状、尺寸均匀、膜层结构致密;薄膜样品中nZn:nO=0.985。 相似文献
67.
Chaojun Liu Xiaojun Liu Qin Wang Liang Zhan Rui Zhang Wenming Qiao Licheng Ling 《Applied Surface Science》2008,254(21):6701-6705
Surface chemistry of pitch-based spherical activated carbon (PSAC) was modified by chemical vapor deposition of NH3 (NH3-CVD) to improve the adsorption properties of uric acid. The texture and surface chemistry of PSAC were studied by N2 adsorption, pHPZC (point of zero charge), acid-base titration and X-ray photoelectron spectroscopy (XPS). NH3-CVD has a limited effect on carbon textural characteristics but it significantly changed the surface chemical properties, resulting in positive effects on uric acid adsorption. After modification by NH3-CVD, large numbers of nitrogen-containing groups (especially valley-N and center-N) are introduced on the surface of PSAC, which is responsible for the increase of pHPZC, surface basicity and uric acid adsorption capacity. Pseudo-second-order kinetic model can be used to describe the dynamic adsorption of uric acid on PSAC, and the thermodynamic parameters show that the adsorption of uric acid on PSAC is spontaneous, endothermic and irreversible process in nature. 相似文献
68.
The effect of oxidant species forming an alcohol molecule for hot-filament chemical vapor deposition (HFCVD) on single-walled carbon nanotubes (SWCNTs) growth has been investigated. To use a graphite rod as a filament for HFCVD to decompose alcohol sources, contamination-free sample surface can be obtained and SWCNTs are successively and densely grown at a lower temperature than those by conventional thermal CVD. It is found that the higher the molecule number of alcohol among CH3OH, C2H5OH, and 2-C3H7OH is, the lower the initial growth rate of SWCNTs is. As for CH3OH, diameter distribution of SWCNTs is dynamically changed with the growth time passed, and a negative growth rate is observed at the later stage of growth. The growth kinetics depending on the alcohol sources is discussed on the basis of a capability of the oxidant species to burn away SWCNTs and deactivation of Co catalysts used for the growth. 相似文献
69.
单壁碳纳米管具有优异的电子学特性,是制备新一代高性能集成电路的重要材料.碳纳米管芯片之路存在诸多挑战,包括直径和手性的控制生长方法、金属性和半导体性单壁碳纳米管的分离方法、器件加工与集成方法等.这些课题从本质上讲大多属于化学问题,因此碳纳米管芯片研究为化学家们提供了新的机遇与挑战.过去10年来,我们围绕单壁碳纳米管的轴向能带工程这一研究思路,开展了一系列碳纳米管芯片的基础探索工作,发展了若干有效的单壁碳纳米管局域能带的调控方法,包括温度阶跃生长法、脉冲供料生长法、基底调控法以及形变调控法等.本文系统地阐述了这些局域能带调控方法,为使读者对该领域的研究进展有一个较为全面的了解,文中对其他课题组开展的代表性工作也给予了综述性介绍. 相似文献
70.
不同形貌氧化锌纳米棒的CVD法制备及生长机制讨论 总被引:3,自引:0,他引:3
采用CVD技术制备了不同形貌的ZnO纳米棒.并利用XRD、SEM、能谱仪、荧光光谱仪对比研究了其表面结构、成份、相结构及光致发光特性.结果表明,样品形貌随着沉积位置的变化而变化,其生长遵循金属自催化机制.并且表明离子化氧空位的存在有利于ZnO的绿光发射. 相似文献