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201.
Cobalt‐Nanocrystal‐Assembled Hollow Nanoparticles for Electrocatalytic Hydrogen Generation from Neutral‐pH Water 下载免费PDF全文
Bingrui Liu Lin Zhang Weilin Xiong Prof. Dr. Mingming Ma 《Angewandte Chemie (International ed. in English)》2016,55(23):6725-6729
Highly active and stable electrocatalysts for hydrogen generation from neutral‐pH water are highly desired, but very difficult to achieve. Herein we report a facile synthetic approach to cobalt nanocrystal assembled hollow nanoparticles (Co‐HNP), which serve as an electrocatalyst for hydrogen generation from neutral‐pH water. An electrode composed of Co‐HNP on a carbon cloth (CC) produces cathodic current densities of 10 and 100 mA cm?2 at overpotentials of ?85 mV and ?237 mV, respectively. The Co‐HNP/CC electrode retains its high activity after 20 h hydrogen generation at a high current density of 150 mA cm?2, indicating the superior activity and stability of Co‐HNP as electrocatalyst. 相似文献
202.
示波滴定法测定合金中铜 总被引:2,自引:0,他引:2
陆为林 《理化检验(化学分册)》1995,31(3):141-142
利用Zn^2+dE/dt~E曲线上有敏锐的切口并可指示波滴定终点的性质提出了用硫脲释放出Cu-EDTA配合物中的EDTA,再用Zn^2+示波滴定该EDTA以测定铜含量的新方法,方法不用指示剂,溶液有颜色不影响测定,进行了多种合金中铜的测定,结果令人满意。 相似文献
203.
Fa Yang Dr. Ping Song Xiaozhi Liu Bingbao Mei Prof. Wei Xing Prof. Zheng Jiang Prof. Lin Gu Prof. Weilin Xu 《Angewandte Chemie (International ed. in English)》2018,57(38):12303-12307
The electrochemical reduction reaction of carbon dioxide (CO2RR) to carbon monoxide (CO) is the basis for the further synthesis of more complex carbon‐based fuels or attractive feedstock. Single‐atom catalysts have unique electronic and geometric structures with respect to their bulk counterparts, thus exhibiting unexpected catalytic activities. A nitrogen‐anchored Zn single‐atom catalyst is presented for CO formation from CO2RR with high catalytic activity (onset overpotential down to 24 mV), high selectivity (Faradaic efficiency for CO (FECO) up to 95 % at ?0.43 V), remarkable durability (>75 h without decay of FECO), and large turnover frequency (TOF, up to 9969 h?1). Further experimental and DFT results indicate that the four‐nitrogen‐anchored Zn single atom (Zn‐N4) is the main active site for CO2RR with low free energy barrier for the formation of *COOH as the rate‐limiting step. 相似文献
204.
合金钢中铬的示波滴定 总被引:3,自引:0,他引:3
根据Pb^2+能与CrO^2-4定量形成沉淀,过量的Pb^2+在dE/dt~E曲线上有敏锐切口的性质,本文研究了用Pb^2+标准溶液直接进行合金钢中铬的示波滴定法新方法,该方法矾不被同时滴定,不用加外指示剂,抗溶剂颜色及沉淀干扰的能力强,具有快速,简便,准确等特点,适用于多种合金钢中铬的快速测定。 相似文献
205.
Hao Ruan Chen Yu Xiaogang Niu Weilin Zhang Hanzhong Liu Limin Chen Ruoyao Xiong Qi Sun Changwen Jin Ying Liu Luhua Lai 《Chemical science》2021,12(8):3004
Intrinsically disordered proteins or intrinsically disordered regions (IDPs) have gained much attention in recent years due to their vital roles in biology and prevalence in various human diseases. Although IDPs are perceived as attractive therapeutic targets, rational drug design targeting IDPs remains challenging because of their conformational heterogeneity. Here, we propose a hierarchical computational strategy for IDP drug virtual screening (IDPDVS) and applied it in the discovery of p53 transactivation domain I (TAD1) binding compounds. IDPDVS starts from conformation sampling of the IDP target, then it combines stepwise conformational clustering with druggability evaluation to identify potential ligand binding pockets, followed by multiple docking screening runs and selection of compounds that can bind multi-conformations. p53 is an important tumor suppressor and restoration of its function provides an opportunity to inhibit cancer cell growth. TAD1 locates at the N-terminus of p53 and plays key roles in regulating p53 function. No compounds that directly bind to TAD1 have been reported due to its highly disordered structure. We successfully used IDPDVS to identify two compounds that bind p53 TAD1 and restore wild-type p53 function in cancer cells. Our study demonstrates that IDPDVS is an efficient strategy for IDP drug discovery and p53 TAD1 can be directly targeted by small molecules.A hierarchical computational strategy for IDP drug virtual screening (IDPDVS) was proposed and successfully applied to identify compounds that bind p53 TAD1 and restore wild-type p53 function in cancer cells. 相似文献
206.
本文报道了铜合金中铜的示波滴定方法。样品酸溶后,用抗坏血酸还的Cu^2+为Cu^+,加入过量的四苯硼钠,在PH5-6的HAc-NaAc缓冲溶液中,定量形成Cu-TPB沉淀,过量的TPB^-,以Tl^+标准溶液进行示波滴定,铜合金中共存元素不干扰测定。铜的测定回收率99.8%-100.1%。进行了多种铜合金中铜含量的测定,结果令人满意。 相似文献
207.
Haibing Guo Hexing Li Jian Zhu Wanhua Ye Minghua Qiao Weilin Dai 《Journal of molecular catalysis. A, Chemical》2003,200(1-2):213-221
A Ru-B amorphous alloy catalyst in the form of ultrafine particles was prepared by chemical reduction of RuCl3 with borohydride in aqueous solution, whose amorphous structure was confirmed by XRD, DSC, and SAED. Heating pretreatment resulted in the rapid crystallization and the deep decomposition of the Ru-B amorphous alloy as well as the abrupt decrease in the surface area due to the gathering of small particles at high temperature. XPS spectra revealed that partial electrons transferred from the alloying B to the metallic Ru in the as-prepared Ru-B sample. In comparison with other catalysts, the as-prepared Ru-B amorphous catalyst exhibited excellent activity and perfect selectivity to
-glucitol as well as superior lifetime during the liquid phase glucose hydrogenation, showing its potential application in industrial process. The higher activity of the Ru-based catalysts than that of other metal catalysts, such as Co-B and Ni-B amorphous catalysts as well as Raney Ni catalysts, demonstrated that the metallic Ru was more active than both metallic Ni and Co for the glucose hydrogenation. Meanwhile, the Ru-B amorphous catalyst exhibited higher activity than its corresponding crystallized Ru-B and pure Ru powder catalysts, showing the promoting effects of both the amorphous structure and the electronic interaction between the metallic Ru and the alloying B, which was briefly discussed based on the kinetic studies and various characterizations. 相似文献
208.
Nanostructured PtRu/C as anode catalysts prepared in a pseudomicroemulsion with ionic surfactant for direct methanol fuel cell 总被引:2,自引:0,他引:2
Nanostructured PtRu/C catalysts have been prepared from a water-in-oil pseudomicroemulsion with the aqueous phase of a mixed concentrated solution of H(2)PtCl(6), RuCl(3), and carbon powder, oil phase of cyclohexane, ionic surfactant of sodium dodecylbenzene sulfonate (C(18)H(29)NaO(3)S), and cosurfactant n-butanol (C(4)H(10)O). Two different composing PtRu/C nanocatalysts (catalyst 1, Pt 20 wt %, Ru 15 wt %; catalyst 2, Pt 20 wt %, Ru 10 wt %) were synthesized. The catalysts were characterized by transmission electron microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, and thermogravimetric analysis, and the particles were found to be nanosized (2-4 nm) and inherit the Pt face-centered cubic structure with Pt and Ru mainly in the zero valance oxidation state. The ruthenium oxide and hydrous ruthenium oxide (RuO(x)()H(y)()) were also found in these catalysts. The cyclic voltammograms (CVs) and chronoamperometries for methanol oxidation on these catalysts showed that catalyst 1 with a higher Ru content (15 wt %) has a higher and more durable electrocatalytic activity to methanol oxidation than catalyst 2 with low Ru content (10 wt %). The CV results for catalysts 1 and 2 strongly support the bifunctional mechanism of PtRu/C catalysts for methanol oxidation. The data from direct methanol single cells using these two PtRu/C as anode catalysts show the cell with catalyst 1 has higher open circuit voltage (OCV = 0.75 V) and maximal power density (78 mW/cm(2)) than that with catalyst 2 (OCV = 0.70 V, P(max) = 56 mW/cm(2)) at 80 degrees C. 相似文献
209.
Three large cerium-containing polytungstoarsenate aggregates have been synthesized via a step-by-step assembly process. Reaction of Na(9)[AsW(9)O(33)] precursors, ceric sulfate and potassium citrate in an acidic aqueous solution at pH = 3 led to the isolation of a new dimeric sandwich-type compound K(9)Na(7)[{Ce(2)O(H(2)O)(5)}{WO(H(2)O)}{AsW(9)O(33)}(2)](2). approximately 48H(2)O. The presence of the citrate anion prevents precipitation of simple lanthanide salts with polyoxometalates. The reaction of compound with alpha-alanine at pH = 2 resulted in the formation of a new alanine-decorated cryptand compound K(2)Na(10)[Ce(4)As(4)W(44)O(151)(ala)(4)(OH)(2)(H(2)O)(10)]. approximately 40H(2)O. The reaction between compound and MnCl(2) at pH = 5 yielded the other inorganic cryptate Mn(0.5)K(5)Na(18)[Ce(4)As(4)W(41)O(149)]. approximately 50H(2)O. All compounds are characterized by elemental analyses, TG analyses, IR, UV-Vis absorption spectra, X-ray photoelectron spectroscopy (XPS), single crystal X-ray diffraction and electrochemical analyses. The crystal data for these compounds: , triclinic, P1[combining macron], a = 12.314(3) A, b = 17.953(4) A, c = 22.355(5) A, alpha = 90.18(3) degrees , beta = 101.97(3) degrees, gamma = 91.08(3) degrees , Z = 1; monoclinic, P2(1)/n, a = 23.4483(15) A, b = 21.8764(13) A, c = 23.6930(14) A, beta = 111.0560 degrees , Z = 2; , triclinic, P1[combining macron], a = 20.636(4) A, b = 23.000(4) A, c = 25.039(4) A, alpha = 81.991(3) degrees , beta = 73.333(3) degrees, gamma = 74.835(3) degrees, Z = 2. Electrochemical analyses of compounds suggest that tetravalent cerium ion can be stabilized by the polyanions with high negative charges. 相似文献
210.
Xiong Gan Zhiming Zhang Shuang Yao Weilin Chen Enbo Wang Hong Zhang 《Journal of Cluster Science》2008,19(2):401-410
Two new one-dimensional chain-like compounds, K4Na4[Mn2(H2O)8Mn4(H2O)2(GeW9O34)2] · 20.5H2O (1) and K2Na4Cu2(H2O)12[Cu(H2O)2Cu4(H2O)2(SiW9O34)2] · 15H2O (2), constructed from the sandwich-type clusters, have been obtained by the routine synthetic reactions in aqueous solutions, and their structures were determined by X-ray single crystal diffraction analysis. The crystal data is following: for 1, space group, monoclinic, P 21/n, a = 16.693(3) Å, b = 14.935(3) Å, c = 20.090(4) Å, β = 92.23(3)°, V = 5004.7(17) Å3, Z = 2; For 2, space group, triclinic, P ?1, a = 11.744(2) Å, b = 13.415(3) Å, c = 17.609(4) Å, α = 73.08(3)°, β = 82.68(3)°, γ = 65.18(3)°, V = 2409.1(8) Å3, Z = 1. The crystal structure of 1 shows a 1D ladder-like chain, built up of the sandwich anions [Mn4(H2O)2(GeW9O34)2]12? and the Mn2+ ions. Compound 2 is a polymeric chain, composed of the Cu-substituted sandwich-type anions [Cu4(H2O)2(SiW9O34)2]12? linked by the Cu(H2O)4 clusters. These extended materials based on the sandwich-type polyoxoanions are rarely reported in the POM chemistry. 相似文献