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981.
Konstantina E. Chrysomallidou Spyros P. Perlepes Aris Terzis Catherine P. Raptopoulou 《Polyhedron》2010
Reactions of malonic acid (H2mal) with PrCl3·6H2O afforded the known complex [Pr2(mal)3(H2O)6]n (1), and compounds [Pr2(mal)3(H2O)6]n·2nH2O (2·2nH2O), [PrCl(mal)(H2O)3]n·0.5nH2O (3·0.5nH2O) and [Pr(mal)(Hmal)(H2O)3]n·nH2O (4·nH2O) using various reaction ratios, reaction media (H2O, MeOH) and pH values. Analogous reactions with CeCl3·7H2O afforded compounds [Ce2(mal)3(H2O)6]n (5), [CeCl(mal)(H2O)3]n·nH2O (6·nH2O) and [Ce(mal)(Hmal)(H2O)3]n·nH2O (7·nH2O). Compounds 2·2nH2O and 3·0.5nH2O were characterized by X-ray crystallography, and 4–7 by microanalytical and spectroscopic data. The malonate(-2) ligand adopts three different coordination modes in the structures of 1–3, i.e., the μ2-κO:κO′:κO″ and the μ4-κ2O:κO′:κ2O″:κO? in 1 and 2 leading to a 3D network structure, and the μ3-κ2O:κO′:κ2O″:κO? in 3 promoting an 1D structure. The thermal decomposition of 1 and 3·0.5nH2O was monitored by TG/DTA and TG/DTG measurements. The structural features of 1–3 are discussed in terms of known malonato(-2) LnIII and CaII complexes. The bioinorganic chemistry relevance of our results is discussed. 相似文献
982.
Cui‐Yu Niu Jiao Jiao Bin Xing Gui‐Chang Wang Xian‐He Bu 《Journal of computational chemistry》2010,31(10):2023-2037
The decomposition mechanisms of methanol on five different Pt surfaces, the flat surface of Pt(111), Pt‐defect, Pt‐step, Pt(110)(1 × 1), and Pt(110)(2 × 1), have been studied with the DFT‐GGA method using the repeated slab model. The adsorption energies under the most stable configuration of the possible species and the activation energy barriers of the possible elementary reactions involved are obtained in this work. Through systematic calculations for the reaction mechanism of methanol decomposition on these surfaces, we found that such a reaction shows the same reaction mechanism on these Pt‐based model catalysts, that is, the final products are all H (Hads) and CO (COads) via O? H bond breaking in methanol and C? H bond scission in methoxy. These results are in general agreement with the previous experimental observations. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010. 相似文献
983.
A simple one-step synthesis of 2,6-dimethylanthracene, 1, in high yield is reported utilizing the easily accessible benzyl alcohol as the starting material. Based on 2,6-dimethylanthracene, two pseudo-triptycene compounds, cis-2,6-dimethyl-9,10-dihydroanthracene-9,10-endo-α,β-succinic anhydride, 2, and cis-2,6-dimethyl-9,10-dihydroanthracene-9,10-endo-α,β-succinyl amine, 3, are firstly synthesized in high yield and they are characterized by single crystal X-ray diffraction. Compound 2 crystallizes in triclinic space group and compound 3 crystallizes in monoclinic P21/c space group. Both compound 2 and 3 exhibit cis-configurations and endo-conformations. Compound 1 exhibits very intense photoluminescence property due to the delocalized electron in the whole molecule, whereas fluorescence quench happens to some extents due to the destruction of the conjugated structure in compound 2. 相似文献
984.
Diffusion of small-molecule penetrants in semi-crystalline polymers is retarded by two factors: penetrant detour bypassing impenetrable crystals and the constraining effect of the crystals on the amorphous component. Previous experiments have shown that the latter factor becomes much less important at higher penetrant concentration in the polymer. Structural changes in a series of poly(ethylene-co-1-octene)s occurring on saturation in n-hexane at 296 K, covering a wide range of crystallinity (17-75 wt.%), were studied by wide-angle X-ray scattering, Raman spectroscopy and NMR spectroscopy. Densification of the crystal unit cell and partial dissolution of the interfacial component on n-hexane sorption are the main experimental findings. The conclusion is that the penetrant molecules increase the mobility of the polymer chain segments adjacent to the crystal interface, enabling better packing of the crystal stems and importantly also causes a reduction in the constraining factor (β) for diffusion. 相似文献
985.
Fernando Godoy Alejandra Gómez A. Hugo Klahn 《Journal of organometallic chemistry》2010,695(3):346-4353
The fulvene complexes [(η6-C5Me4CH2)Re(CO)2(R)] (1a, RI; 1b, RC6F5) react at the exocyclic methylene carbon with a vinylmagnesium bromide solution to produce the anionic species [(η5-C5Me4CH2CHCH2)Re(CO)2(R)]−. Protonation with HCl at 0 °C produces the hydride complexes [trans-(η5-C5Me4CH2CHCH2)Re(CO)2(R)(H)] (2a, RI; 2b, RC6F5). Thermolysis of an hexane solution of the iodo-hydride (2a) under a CO atmosphere yields the complex [(η5-C5Me4CH2CHCH2)Re(CO)3] (3) and [Re(CO)5I] as by-product. Thermolysis of 2b produced three new products, mainly the chelated complex [(η5:η2-C5Me4CH2CHCH2)Re(CO)2] (4) and complex 3, with a non-coordinated olefin group, in moderated yield, and traces of [Re(CO)5(C6F5)]. Thermolysis of an hexane solution of 2 in presence of an excess of PMe3, afforded the phosphine derivative [(η5-C5Me4CH2CHCH2)Re(CO)2(PMe3)] (5). All the complexes were characterized by IR, 1H, 13C and 31P NMR spectroscopies and mass spectrometry. The molecular structure of 4 has also been determined. The molecule exhibits a formal three-legged piano-stool structure, with two CO groups, and the third position corresponding to the η2-coordination of the propenyl side arm of the η5-C5Me4 ring. 相似文献
986.
Mitsushiro Nomura Shigemi Kondo Eriko Suzuki Glenn V. Alea Chikako Fujita-Takayama Masatsugu Kajitani 《Journal of organometallic chemistry》2010,695(21):2366-2895
Eight new sulfur-rich [CpCo(dithiolene)] complexes were synthesized from [Zn(dmit)2]2− as a starting material. The structures, electrochemical behavior and electronic absorption spectra of the sulfur-rich [CpCo(S2C2S2Y)] complexes could be compared with the early data of analogous Ni complexes. [CpCo(pddt)] (Y = -(CH2)3-), [CpCo(dpdt)] (Y = -CH2C(CH2)CH2-), [CpCo(bddt)] (Y = -(CH2)4-), [CpCo(dtdt)] (Y = -CH2SCH2-) and [CpCo(poddt)] (Y = -CH2C(O)CH2-) crystallized in all isostructural with the corresponding paramagnetic [CpNi(dithiolene)] complexes, but [CpCo(dmid)] (Y = CO), [CpCo(dddt)] (Y = -(CH2)2-) and [CpCo(F2pddt)] (Y = -CH2CF2CH2-) crystallized in non-isostructural with them. These molecules are associated with intermolecular short S?S contacts in the crystals. [CpCo(F2pddt)] did not show any remarkable S?S contacts but indicated interesting fluorine segregation and Cp?Cp face-to-face interactions. Redox potentials of [CpCo(dithiolene)] complexes were obtained with the cyclic voltammetry measurements and dimerized by electrochemical oxidations. Electronic absorption spectra of [CpCo(dithiolene)] complexes showed visible absorption in the range of 585-701 nm as lowest energy wavelengths (? = 9800-11,800 M−1 cm−1) in solutions, and they were higher energy than those of [CpNi(dithiolene)] complexes (near-IR). 相似文献
987.
Gerard A. van Albada Maarten G. van der Horst Simon J. Teat Patrick Gamez Olivier Roubeau Ilpo Mutikainen Urho Turpeinen Jan Reedijk 《Polyhedron》2009
In this study the synthesis, crystal structure and characterization of three new transition metal polynuclear compounds with formula [Cu(dipm)(μ-dca)2]n(H2O) (1), [Ni(dipm)(μ-dca)2]n(C2H6O)1/2 (2) and [Cd(dipm)(μ-dca)2]n (3) (in which dipm = bis(pyrimidin-2-yl)amine and dca = dicyanamide) are reported. The isostructural compounds 1 and 2 contain a double-bridging end-to-end dca unit connecting two metal ions and a single bridging end-to-end dca unit between subsequent metals. Compound 3 exhibits only single bridging end-to-end dca units, oriented in three directions, giving rise to a 3D framework. 相似文献
988.
针对高空速下捕获痕量毒物分子的环境净化要求, 尝试调控介孔材料孔壁结构以提高其吸附小分子环境污染物的效率. 通过调节合成体系的 pH 值、加入无机盐以及控制表面活性剂浓度等方法, 改变硅物种与模板剂胶束的组装速度或无机-有机液晶相的存在形态, 研制含有孔壁缺陷位的介孔分子筛新材料. 通过 X 射线衍射和低温氮气吸附研究了样品的结构特性, 并采用高分辨透射电镜和固体核磁技术证实了介孔材料孔壁缺陷位的形成. 以挥发性吡咯烷亚硝胺为靶标分子, 考察了所得材料的吸附性能. 结果表明, 大量缺陷空位的存在成倍地提高了介孔分子筛吸附挥发性亚硝胺的效率, 为设计研制环保新材料提供了新思路. 相似文献
989.
通过化学合成获得丁吡吗啉及其苯基类似物,并对其杀菌活性进行了比较.借助X射线晶体衍射方法,对丁吡吗啉的结构进行了解析.进一步选择6-31G(2df,2pd)基组,利用密度泛函理论B3LYP方法对丁吡吗啉及其苯基类似物的空间几何结构进行优化,借助前线分子轨道、Mulliken电荷、自然键轨道(NBO)分析、表观静电势等对丁吡吗啉及其苯基类似物的电子结构与其杀菌活性相关性进行了理论探讨.结果表明吡啶环取代苯环后,一方面吡啶环上的N原子是一个负电中心,有利于与受体分子间形成氢键等相互作用;另一方面,吡啶环又是一个缺电子的芳环,与苯环相比,在与受体的π-π相互作用中能起到更好的电子接受体的作用.这两种因素使得丁吡吗啉更容易与受体结合,因而活性更高. 相似文献
990.
以D/L-缬氨醇为原料,通过二步反应得到价廉易得的拆分剂碘化(R)/(S)-N,N,N-三甲基-1-羟基-3-甲基-2-丁铵,采用包结拆分法,成功实现了对1,1′-联-2-萘酚(BINOL)的拆分.对具有(R)-构型的季铵盐与(R)-BINOL在甲醇中所形成包结物的晶体结构分析结果表明:I-离子桥联主体(拆分剂)的醇羟基和客体(BINOL)的酚羟基形成O-H…I-氢键,以及相邻层的主客体分子之间的C-H…O氢键相互作用是在包结物中实现手性识别的关键.同时对两个包结物的溶液和固体圆二色(CD)光谱进行了研究. 相似文献