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111.
The paper manufacturing process remained unchanged for many centuries, until, in the nineteenth century, the crisis of rags led industrialized countries to patent new production processes with different raw materials. This study deals with this period of transition by analyzing four samples stored at the archives of Superintendency Beni Architettonici per il Paesaggio e per il Patrimonio Storico Artistico ed Etnoantropologico (BAPPDAD) of Venice Lagoon, based in the Palazzo Ducale.The samples were analyzed by FT-IR (ATR), SEM-EDS, HPLC-MS/MS and Py-GC/MS. These techniques allow the characterization of various raw materials and adhesives used in various stages of paper production.These analyses have found a gradual introduction of ground wood in the composition of papers from the mid-nineteenth century, and the use of rosin as glue only in more recent documents. 相似文献
112.
氨酯丙烯酸酯树脂的合成及其固化反应动力学研究 总被引:3,自引:0,他引:3
用不同分子量的聚氧化丙烯二元醇合成了一系列氨酯丙烯酸酯齐聚物(UAO)以及含硬段/软段结构的UAO,并用FT-IR跟踪了这类UAO的合成过程。通过UAO的链端双键测定,以及GPC、VPO测定的分子量,表征了UAO的数均官能团度。进一步通过FT-IR研究了由UAO与甲基丙烯酸甲酯形成的氨酯丙烯酸酯树脂(UAR)固化时的共聚反应动力学,发现其共聚反应速率与体系中的扩散效应密切相关。在这类UAO中引入硬段后,共聚合体系呈现出反常的动力学行为,与网络结构形成过程中材料的形态发展有关。 相似文献
113.
The nature of phosphonopeptides containing N-terminal l-phenylalanine (l-Phe), namely l-Phe-dl-NH-CH(CH(CH3)2)-PO3H2 (A), l-Phe-l-NH-CH(CH3)-PO3H2 (B), and l-Phe-dl-NH-CH(CH2CH2COOH)-PO3H2 (C) (Fig. 1 presents molecular structure of these molecules), adsorbed on electrochemically roughened and colloidal silver surfaces has been explored by surface-enhanced Raman spectroscopy (SERS). To reveal adsorption mechanism of these species on the basis of their SERS spectra at first Fourier-transform Raman (FT-RS) and absorption infrared (FT-IR) spectra of non-adsorbed molecules were measured. Examination of enhancement, frequency shifts, and changes in relative intensities of SERS bands due to adsorption and surface roughens variation reveals that the tilted compounds adsorb on the electrochemically roughened silver substrate in similar way, while they behave differently on the colloidal silver surface. A stronger enhancement of in-plane ring vibrations of the l-Phe ring, i.e., ν3 and ν18b (B2), over these of the A2 symmetry in all SERS spectra on the electrochemically roughened silver substrate suggests that the ring interacts with this surface adopting slightly deflect orientation from the perpendicular one. Also, enhancement of PO and -CH2-/-CH3 fragments vibrations points out that they are involved in adsorption process on this substrate. This conclusion was drawn on the basis of the enhancement of 1274-1279 and 1138-1152 (ν(PO)), 1393-1400 (δ(CH) + ρb(CNH2) + ν(C-CO) + δ(CH3)), ∼1455 (δ(CCH3/CCH2) + ρb(CH3/CH2), and 1505-1512 cm−1 (δ(CH2) + Phe(ν19a)) bands. Although a relative intensity ratio of these bands in the presented SERS spectra is different. On the other hand, on the colloidal silver nanoparticles, the aromatic ring of all molecules is lying flat or takes almost parallel orientation to this surface. Besides, A interacts also via P-terminal group (568, 765, 827, 1040, and 1150 cm−1), whereas B mainly through NH2-C-(CO)-CNH-(712 and 1255 cm−1). In the case of C, it adsorbs on the silver colloidal surface mainly through the aromatic ring of l-Phe, while other fragments of the molecule are in close proximity to this surface as comes off the weak enhancement of bands due to the aliphatic vibrations. 相似文献
114.
东胜长焰煤热解含氧官能团结构演化的13C-NMR和FT-IR分析 总被引:1,自引:0,他引:1
以东胜煤田色拉一号井田2号煤层长焰煤为研究对象,利用浮沉离心法富集其镜质组。基于工业分析、元素分析、13C-NMR、FT-IR、谱图分峰拟合技术和化学分析测试,求取镜煤及一系列热解煤含氧官能团结构与含量参数,从不同角度研究了含氧官能团的分布规律与演化特点。镜煤中羧基、羰基含量分别为8.91~10.90 mol/kg、1.61~1.79 mol/kg,随热解温度升高羧基显著减少。热解作用促使以端基形式连接在脂肪链或脂肪环结构氧上的甲基和亚甲基首先脱去,且在温度高于350 ℃后基本稳定。氧在热解过程赋存状态的变化是芳香体系与脂肪体系相互竞争的结果,510 ℃热解煤中芳香类氧和脂肪类氧的含量分别为7.49、3.45 mol/kg。羟基的演化过程与热解过程中氧的赋存状态密切相关。随着热解过程的进行,在热解温度低于440 ℃时,各种羟基含量均减少,热解过程对于大分子网络的破坏干扰了各种氢键作用,而羟基π作用则暂时增强,至510 ℃时各种氢键含量均降为最低。东胜长焰煤中含氧官能团化学活性顺序为:[COOH]>[R-O]>[Ar-O-Ar,Ar-O-C,C-O-C]>[C=O]。镜煤非活性醚键含量为0.68 mol/kg,活性醚键为0.48 mol/kg,主要为非活性醚键。 相似文献
115.
Andrew O. Odeh 《燃料化学学报》2015,43(2):129-137
This paper analyzes the coal to char stages of char formation of six coals of different ranks by using Fourier transform infrared coupled w ith attenuated total reflectance(ATR-FTIR).The chars w ere obtained by coal pyrolysis carried out at temperature range of 450~700℃.The data obtained show s the pragmatic disappearance of the aliphatic hydrogen content w ith increasing char formation temperature.Numerical evaluation of the spectra enabled the determination of aromaticity,fa.The aromaticity w as found to be betw een 0.66~0.79 for lignite,0.75~0.90 for sub-bituminous,0.84~1.00 for low volatile bituminous,0.83~1.00 for high volatile bituminous,0.94~1.00 for semi-anthracite,and 0.97~1.00 for anthracite respectively.With increasing rank of coal samples,spectra exhibit rising aromaticity and enhanced condensation of aromatic rings,w hereas the aliphatic chain lengths decrease. 相似文献
116.
SCR脱硝过程中SO催化氧化的原位红外研究 《燃料化学学报》2015,43(8):1018-1024
采用工业用V2O5-WO3/TiO2催化剂,基于傅里叶原位红外光谱(FT-IR)技术考察SO2的氧化过程及烟气组分对SO2氧化行为的影响;结果表明,SO2在催化剂表面氧化主要是首先吸附在催化剂表面V2O5活性位上,占据其O原子,以SO2-3形式存在,后与催化剂表面V5+-OH发生反应,生成金属硫酸盐(VOSO4)中间产物,O2重新氧化催化氧化过程中由于被SO2夺取O原子而被还原的V2O5物种,使V4+转化为V5+,促进金属硫酸盐(VOSO4)向SO3转化;SO2与NO、NH3的竞争吸附阻碍SO2在V2O5活性点位上的氧化;在SCR中,NO的脱除与SO2的氧化是相互抑制的关系。 相似文献
117.
118.
Subashchandrabose S Saleem H Erdogdu Y Rajarajan G Thanikachalam V 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,82(1):260-269
FT-Raman and FT-IR spectra were recorded for 3-pentyl-2,6-diphenylpiperidin-4-one (PDPO) sample in solid state. The equilibrium geometries, harmonic vibrational frequencies, infrared and the Raman scattering intensities were computed using DFT/6-31G(d,p) level. Results obtained at this level of theory were used for a detailed interpretation of the infrared and Raman spectra, based on the total energy distribution (TED) of the normal modes. Molecular parameters such as bond lengths, bond angles and dihedral angles were calculated and compared with X-ray diffraction data. This comparison was good agreement. The intra-molecular charge transfer was calculated by means of natural bond orbital analysis (NBO). Hyperconjugative interaction energy was more during the π–π* transition. Energy gap of the molecule was found using HOMO and LUMO calculation, hence the less band gap, which seems to be more stable. Atomic charges of the carbon, nitrogen and oxygen were calculated using same level of calculation. 相似文献
119.
Farag AA Haggag SM Mahmoud ME 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,82(1):467-474
Spectral–optical–electrical–thermal properties of deposited thin films of nano-sized calcium(II)-8-hydroxy-5,7-dinitroquinolate complex, Ca[((NO2)2-8HQ)2], were explored, studied and evaluated in this work. Thin films of Ca[((NO2)2-8HQ)2] were assembled by using a direct, simple and efficient layer-by-layer (LBL) chemical deposition technique. The optical properties of thin films were investigated by using spectrophotometric measurements of transmittance and reflectance at normal incidence in the wavelength range 200–2500 nm. The refractive index, n, and the absorption index, k, of Ca[((NO2)2-8HQ)2] films were determined from the measured transmittance and reflectance. The real and imaginary dielectric constants were also determined. The analysis of the spectral behavior of the absorption coefficient in the intrinsic absorption region reveals a direct allowed transition with band gaps of 1.1 eV and 2.4 eV for the optical and transport energy gaps, respectively. The current–voltage characteristics of Ca[((NO2)2-8HQ)2] showed a trap-charge limited conduction in determining the current at the intermediate and high bias regimes. Graphical representation of the current–voltage characteristics yields three distinct linear parts indicating the existence of three conduction mechanisms. Structural characterization and identification were confirmed by using Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy (SEM) was also used to image the surface morphology of the deposited nano-sized metal complex and such study revealed a high homogeneity in surface spherical particle distribution with average particles size in the range 20–40 nm. Thermal gravimetric analysis (TGA) was also studied for [(NO2)2-8HQ] and Ca[((NO2)2-8HQ)2] to evaluate and confirm the thermal stability characteristics incorporated into the synthesized nano-sized Ca[((NO2)2-8HQ)2] complex. 相似文献
120.
Amalanathan M Rastogi VK Joe IH Palafox MA Tomar R 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(5):1437-1444
The FT-IR and Raman spectra of 3,5-dinitrobenzoic acid (DNBA) have been recorded and analyzed. The equilibrium geometry, various bonding and harmonic vibrational wavenumbers have been calculated with the help of density functional theory (DFT) method. Most of the vibrational modes are observed in the expected range. Mulliken population analysis shows the interactions C-N-O?H-C and C-O?H-C. The most possible interaction is explained using natural bond orbital (NBO) analysis. The strengthening and polarization of the CO bond increases due to the degree of conjugation. HOMO-LUMO energy and the thermodynamic properties are also evaluated. 相似文献