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91.
In this research, a novel organic–inorganic hybrid salt, namely, N1,N1,N2,N2‐tetramethyl‐N1,N2‐bis(sulfo)ethane‐1,2‐diaminium tetrachloroferrate ([TMBSED][FeCl4]2) was prepared and characterized by Fourier‐transform infrared spectroscopy (FT‐IR), energy‐dispersive X‐ray spectroscopy (EDX), elemental mapping, field emission scanning electron microscopy (FE‐SEM), X‐ray diffraction (XRD), thermal gravimetric (TG), differential thermal gravimetric (DTG), and vibrating‐sample magnetometry (VSM) analyses. Catalytic activity of the hybrid salt was tested for the synthesis of N,N′‐alkylidene bisamides through the reaction of benzamide (2 eq.) and aromatic aldehydes (1 eq.) under solvent‐free conditions in which the products were obtained in high yields and short reaction times. The catalyst was superior to many of the reported catalysts in terms of two or more of these factors: the reaction medium and temperature, yield, time, and turnover frequency (TOF). [TMBSED][FeCl4]2 is a Brønsted–Lewis acidic catalyst; there are two SO3H groups (as Brønsted acidic sites) and two tetrachloroferrate anions (as Lewis acidic sites) in its structure. Highly effectiveness of the catalyst for the synthesis of N,N′‐alkylidene bisamides can be attributed to synergy of the Brønsted and Lewis acids and also possessing two sites of each acid. 相似文献
92.
《Journal of Coordination Chemistry》2012,65(16):2863-2874
{[Cu2(btm)2(Hbtc)(H2btc)2(H2O)]·9.5H2O}n (1), [Cu(bte)(H2btc)2]n (2) {[Cu(btp)(H2btc)2]·0.25H2O}n (3) (btm?=?bis(1,2,4-triazol-1-yl)methane, bte?=?bis(1,2,4-triazol-1-yl)ethane, btp?=?bis(1,2,4-triazol-1-yl)propane, H3btc?=?benzene-1, 3, 5-tricarboxylic acid) have been synthesized and structurally characterized. 1 features a 1-D double chain, which is interconnected by classical hydrogen-bonding (O–H?O) and π–π interactions to lead to a 3-D supramolecular architecture. 2 and 3 are both 1-D single chains, which are interconnected by π–π interactions to 2-D layer architectures. Elemental analysis, XRD, IR, TG and EPR spectra have been carried out and discussed. 相似文献
93.
A series of group 12 metal coordination polymers with 1,2-bis(diphenylphosphino)ethane dioxide (dppeO2), {[ZnCl2(μ-dppeO2)]·CH2Cl2}n (1·CH2Cl2), [ZnBr2(μ-dppeO2)]n (2), [CdI2(μ-dppeO2)]n (4), [(HgI2)2(μ-dppeO2)]n (5), [Zn(SCN)(μ-SCN)(μ-dppeO2)]n (6), and [Cd(NO3)(μ-SCN)(μ-dppeO2)]n (7), have been synthesized and structurally characterized. The structures of the compounds are all based on an infinite 1D chain constructed by four-coordinate metal ions and dppeO2 ligands adopting the trans bridging coordination fashion. In the coordination polymers 1, 2 and 4, the halide ions act as terminal ligands, leading to discrete 1D chains with alternative MX2 and dppeO2 repeating units. The mercury compound 5 features a unique square-wave-like inorganic chain –[Hg(1)–I–Hg(2)–I]–, and the 1D HgI2(μ-dppeO2) chains are further linked by HgI2 bridges to form a 3D network. In the thiocyanate-containing compounds 6 and 7, the 1D chains are linked by one (6) or two (7) bridging SCN– ions to result in 2D layered structures. Solid-state emission spectra of the coordination polymers show different variations compared to the free dppeO2 ligand, such as enhancement (1, 2, 6 and 7), shift (3 and 4) and quenching (5) upon metal coordination. 相似文献
94.
相比于传统热驱动的低温蒸馏工艺, 基于金属有机框架(Metal-organic frameworks, MOFs)的膜分离是一种在技术和成本上可行的乙烷/乙烯分离替代方案. 为了加速MOF膜在这一气体分离领域中的应用, 本工作提出了两步筛选策略对12,020个真实MOF膜材料进行了大规模计算筛选, 其中MISQIQ04表现出最高的乙烷/乙烯膜选择系数(4.16)和较高的乙烷渗透率(4.35×105 Barrer). 通过结构-性能关系分析, 可以发现窄孔径和低孔隙率的MOFs是选择性分离乙烷的最佳膜材料, 并且乙烷的选择性吸附对乙烷/乙烯膜分离过程起着主导作用. 与传统计算筛选方法相比, 本工作所提出的筛选策略降低了约87.1%的计算时间成本. 为了进一步缩短模拟时间, 本工作还开发了机器学习分类模型以实现对高性能MOF膜的快速预筛选并探讨了该模型的可移植性. 结果表明, 增加数据集的多样性有助于提高所开发模型的可移植性和泛化能力. 相似文献
95.
Bhim Chandra Mondal 《Analytica chimica acta》2003,477(1):73-80
A method for the simultaneous preconcentration and determination of Hg(II) and MeHg(I) at the ng ml−1 level has been developed. This method is based on solid phase extraction using a newly synthesized chelating resin containing nitrogen and sulphur donor sites of the 1,2-bis(o-aminophenylthio)ethane moiety that is very selective for mercury. The characterization of the resin has been carried out by elemental analyses, infrared spectral data, thermogravimetric analysis and metal ion capacities. The resin is highly selective for Hg(II) and MeHg(I) with an exchange capacity of 0.38 and 0.30 mmol g−1, respectively. Various parameters like pH, column flow rate, desorbing agents are optimized. Cold vapour atomic absorption spectrometry (CVAAS) was used to measure the concentration of both species of mercury. The calibration graph was linear upto 10 ng ml−1 with a 3σ detection limit of 0.09 ng ml−1. The recovery of Hg(II) and MeHg(I) was found to be 98.9±2.0 and 98.0±1.1%, respectively. The method has been used for routine determination of trace levels of mercury species in natural waters to comply with more stringent regulations. 相似文献
96.
乙烷部分氧化超细Fe-Mo-O催化剂的研究 总被引:2,自引:2,他引:2
采用溶胶-凝胶法制备了Fe-Mo-O催化剂,用XRD、TEM、BET、IR、TPR、TPD和微反等技术研究了催化剂晶体结构、表面构造、晶格氧活泼性、化学吸附和乙烷部分氧化反应性能。Fe-Mo-O复合氧化物催化剂是由超细微粒组成,微粒粒径约10 nm~20 nm,比表面积为48.1 m2/g。催化剂表面由Lewis碱位(Mo=O键的端氧和Fe-O-Mo键中的桥氧)及Lewis酸位构成。乙烷能以甲基中的H原子吸附在催化剂表面Lewis碱位Mo=O的端氧上形成分子吸附态,其部分氧化产物主要是C2H4和少量的CH3CHO。 相似文献
97.
Jun Xia Xiao‐Lin Gong Xing Fan 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(10):878-882
Assemblies of pyrazine‐2,3‐dicarboxylic acid and CdII in the presence of bis(1,2,4‐triazol‐1‐yl)butane or bis(1,2,4‐triazol‐1‐yl)ethane under ambient conditions yielded two new coordination polymers, namely poly[[tetraaqua[μ2‐1,4‐bis(1,2,4‐triazol‐1‐yl)butane‐κ2N4:N4′]bis(μ2‐pyrazine‐2,3‐dicarboxylato‐κ3N1,O2:O3)dicadmium(II)] dihydrate], {[Cd2(C6H2N2O4)2(C8H12N6)(H2O)4]·2H2O}n, (I), and poly[[diaqua[μ2‐1,2‐bis(1,2,4‐triazol‐1‐yl)ethane‐κ2N4:N4′]bis(μ3‐pyrazine‐2,3‐dicarboxylato‐κ4N1,O2:O3:O3′)dicadmium(II)] dihydrate], {[Cd2(C6H2N2O4)2(C6H8N6)(H2O)2]·2H2O}n, (II). Complex (I) displays an interesting two‐dimensional wave‐like structure and forms a distinct extended three‐dimensional supramolecular structure with the help of O—H...N and O—H...O hydrogen bonds. Complex (II) has a three‐dimensional framework structure in which hydrogen bonds of the O—H...N and O—H...O types are found. 相似文献
98.
Assembled complex, Fe(bpa)2(NCX)2 (bpa=1,2-bis(4-pyridyl)ethane; X=S, Se, BH3) enclathrated diphenylmethane. The skeletons were interpenetrating structures for NCS and NCSe complexes, while 2D grid structure
was obtained for NCBH3 complex. The assembled iron complexes showed spin-crossover phenomena by enclathrating diphenylmethane. The ratio of spin
transition and the transition temperature depended on the assembled structure. 相似文献
99.
MgO改性的γ-Al2O3负载CuCl2-KCl催化剂上乙烷氧氯化制氯乙烯 总被引:1,自引:0,他引:1
采用浸渍法制备了不同含量MgO改性的γ-Al2O3,采用X射线衍射、N2物理吸附、NH3的程序升温脱附和程序升温还原等手段表征了催化剂的结构、表面酸性和氧化还原性质,并对CuCl2-KCl/MgO-Al2O3催化剂催化乙烷氧氯化制氯乙烯反应进行了活性评价.XRD结果表明,通过使用Mg(NO3)2溶液浸渍γ-Al2O3载体在表面上形成了表层镁铝尖晶石结构.TPR结果说明,表层MgAl2O4的生成加强了活性物种Cu与载体的作用,促进了CuⅡ→CuⅠ的还原.CuCl2-KCl/MgO-Al2O3催化剂对乙烷氧氯化反应的催化性能表明,随着MgO-Al2O3载体中MgO含量的增加,乙烷转化率和氯乙烯选择性逐渐升高,当MgO含量增加至10%时,氯乙烯的选择性最高(49.1%).NH3-TPD结果表明,表层MgAl2O4中和了γ-Al2O3表面的强酸中心,增加了弱酸中心的数量是氯乙烯选择性提高的主要原因. 相似文献
100.