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941.
Extent-based kinetic identification is a kinetic modeling technique that uses concentration measurements to compute extents and identify reaction kinetics by the integral method of parameter estimation. This article considers the case where spectroscopic data are used together with a calibration model to predict concentrations. The calibration set is assumed to be constructed from reacting data that include pairs of concentration and spectral data. Alternatively, one can use the concentration- and spectral contributions of the reactions and mass transfers, which are obtained by pretreatment in reaction- and mass-transfer-variant form. The extent-based kinetic identification using concentrations predicted from spectroscopic data is illustrated through the simulation of both a homogeneous and a gas–liquid reaction system. 相似文献
942.
Tuan‐Anh Nguyen Julien Roger Houssein Nasrallah Vincent Rampazzi Sophie Fournier Hlne Cattey E. Daiann Sosa Carrizo Paul Fleurat‐Lessard Charles H. Devillers Nadine Pirio Dominique Lucas Jean‐Cyrille Hierso 《化学:亚洲杂志》2020,15(18):2879-2885
Di‐tert‐butylated‐bis(phosphino)ferrocene ligands bearing phosphino substituents R (R=phenyl, cyclohexyl, iso‐propyl, mesityl, or furyl) allow tuning the selective formation of Au(I) halide complexes. Thus, dinuclear linear two‐coordinate, but also rare mononuclear trigonal three‐coordinate and tetrahedral four‐coordinate complexes were formed upon tuning of the conditions. Both Au(I) chloride and rarer Au(I) iodide complexes were synthesized, and their X‐ray diffraction analysis are reported. The significance of the control of structure and nuclearity in Au(I) complexes is further illustrated herein by its strong effect on the efficiency and selectivity of gold‐catalysed cycloisomerization. Cationic linear digold(I) bis(dicyclohexylphosphino) ferrocenes outperform other catalysts in the demanding regioselective cycloisomerization of enyne sulphonamides into cyclohexadienes. Conversely, tetrahedral and trigonal cationic monogold(I) complexes were found incompetent for enyne cycloaddition. We used the two‐coordinate linear electron‐rich Au(I) complex 2 b (R=Cy) to extend the scope of selective intramolecular cycloaddition of different 1,6‐enyne sulfonylamines with high activity and excellent selectivity to the endo cyclohexadiene products. 相似文献
943.
Lakshmi-Narayana A. Prakash N. Guru Dhananjaya M. Hussain O. M. Jun Qiu Ye Julien C. M. 《Journal of Solid State Electrochemistry》2020,24(6):1371-1385
Journal of Solid State Electrochemistry - Li2TiO3 (LTO) is a promising Ti-based material showing interesting electrochemical performance, good structural stability, cost-effectiveness, and... 相似文献
944.
Stphanie Norsikian Cedric Tresse Marc Franois‐Eude Louis Jeanne‐Julien Guillaume Masson Vincent Servajean Grgory Genta‐Jouve Jean‐Marie Beau Emmanuel Roulland 《Angewandte Chemie (International ed. in English)》2020,59(16):6612-6616
A total synthesis of tiacumicin B, a natural macrolide whose remarkable antibiotic properties are used to treat severe intestinal infections, is reported. The strategy is in part based on the prior synthesis of the tiacumicin B aglycone, and on the decisive use of sulfoxides as anomeric leaving groups in hydrogen‐bond‐mediated aglycone delivery (HAD). This new HAD variant permitted highly β‐selective rhamnosylation and noviosylation. To increase convergence, the rhamnosylated C1–C3 fragment thus obtained was anchored to the C4–C19 aglycone fragment by adapting the Suzuki–Miyaura cross‐coupling used for the aglycone synthesis. Ring‐size‐selective macrolactonization provided a compound engaged directly in the noviolysation step with virtually total β selectivity. The final efficient removal of all the protecting groups provided synthetic tiacumicin B. 相似文献
945.
Dillon T. Flood Xuejing Zhang Xiang Fu Zhenxiang Zhao Shota Asai Brittany B. Sanchez Emily J. Sturgell Julien C. Vantourout Paul Richardson Mark E. Flanagan David W. Piotrowski Dominik K. Klmel Jinqiao Wan Mei‐Hsuan Tsai Jason S. Chen Phil S. Baran Philip E. Dawson 《Angewandte Chemie (International ed. in English)》2020,59(19):7377-7383
DNA encoded libraries (DEL) have shown promise as a valuable technology for democratizing the hit discovery process. Although DEL provides relatively inexpensive access to libraries of unprecedented size, their production has been hampered by the idiosyncratic needs of the encoding DNA tag relegating DEL compatible chemistry to dilute aqueous environments. Recently reversible adsorption to solid support (RASS) has been demonstrated as a promising method to expand DEL reactivity using standard organic synthesis protocols. Here we demonstrate a suite of on‐DNA chemistries to incorporate medicinally relevant and C?S, C?P and N?S linkages into DELs, which are underrepresented in the canonical methods. 相似文献
946.
Dr. Guodong Qi Dr. Yueying Chu Dr. Qiang Wang Xingxing Wang Prof. Yi Li Dr. Julien Trébosc Prof. Olivier Lafon Prof. Jun Xu Prof. Feng Deng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(44):19700-19706
Lewis acid zeolites have found increasing application in the field of biomass conversion, in which the selective transformation of carbonyl-containing molecules is of particular importance due to their relevance in organic synthesis. Mechanistic insight into the activation of carbonyl groups on Lewis acid sites is challenging and critical for the understanding of the catalytic process, which requires the identification of reaction intermediates. Here we report the observation of a stable surface gem-diol-type species in the activation of acetone on Sn-β zeolite. 13C, 119Sn, and 13C–119Sn double-resonance NMR spectroscopic studies demonstrate that only the open Sn site ((SiO)3Sn-OH) on Sn-β is responsible for the formation of the surface species. 13C MAS NMR experiments together with density functional theory calculations suggest that the gem-diol-type species exhibits high reactivity and can serve as an active intermediate in the Meerwein—Ponndorf–Verley–Oppenauer (MPVO) reaction of acetone with cyclohexanol. The gem-diol-type species offers an energy-preferable pathway for the direct carbon-to-carbon hydrogen transfer between ketone and alcohol. The results provide new insights into the transformation of carbonyl-containing molecules catalyzed by Lewis acid zeolites. 相似文献
947.
948.
Ish K. Khanna Francis J. Koszyk Michael A. Stealey Richard M. Weier Janet Julien Richard A. Mueller 《Journal of carbohydrate chemistry》2013,32(6):843-878
Abstract A useful methodology for the synthesis of a number of 2-, 3- and 2,3-disubstituted deoxynojirimycin analogs is reported. It has been found that the epoxides in stereoselectively synthesized N-carboalkoxy-2,3-anhydro-1-deoxymannojirimycins (4 and 5) react with N-, S- and F- nucleophiles to give a mixture of gluco and altro products. The 3-azido altro compound (12b) yields the desired gluco derivative (40) by oxidation, in situ epimerization at C-3, followed by stereoselective reduction of the carbonyl group. The azido intermediate (12a) affords the 2,3-diazido gluco compound (51) by double inversion at C-3. Attempts have been made to understand the factors contributing to the opening of epoxides (4, 5 and 9) by different nucleophiles. 相似文献
949.
Dr. Florian Rechenmacher Dr. Stefanie Neubauer Dr. Carlos Mas‐Moruno Dr. Petra M. Dorfner Dr. Julien Polleux Dr. Judith Guasch Dr. Bert Conings Prof. Dr. Hans‐Gerd Boyen Dr. Alexander Bochen Prof. Dr. Tariq R. Sobahi Priv.‐Doz. Dr. Rainer Burgkart Prof. Dr. Joachim P. Spatz Prof. Dr. Reinhard Fässler Prof. Dr. Horst Kessler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(28):9218-9223
We present a click chemistry‐based molecular toolkit for the biofunctionalization of materials to selectively control integrin‐mediated cell adhesion. To this end, α5β1‐selective RGD peptidomimetics were covalently immobilized on Ti‐based materials, and the capacity to promote the selective binding of α5β1 was evaluated using a solid‐phase integrin binding assay. This functionalization strategy yielded surfaces with a nine‐fold increased affinity for α5β1, in comparison to control samples, and total selectivity against the binding of the closely related integrin αvβ3. Moreover, our methodology allowed the screening of several phosphonic acid containing anchoring units to find the best spacer–anchor moiety required for establishing an efficient binding to titanium and to promote selective integrin binding. The integrin subtype specificity of these biofunctionalized surfaces was further examined in vitro by inducing selective adhesion of genetically modified fibroblasts, which express exclusively the α5β1 integrin. The versatility of our molecular toolkit was proven by shifting the cellular specificity of the materials from α5β1‐ to αvβ3‐expressing fibroblasts by using an αvβ3‐selective peptidomimetic as coating molecule. The results shown here represent the first functionalization of Ti‐based materials with α5β1‐ or αvβ3‐selective peptidomimetics that allow an unprecedented control to discriminate between α5β1‐ and αvβ3‐mediated adhesions. The role of these two integrins in different biological events is still a matter of debate and is frequently discussed in literature. Thus, such bioactive titanium surfaces will be of great relevance for the study of integrin‐mediated cell adhesion and the development of new biomaterials targeting specific cell types. 相似文献
950.
Dr. Mona A. Furrer Amine Garci Emmanuel Denoyelle‐Di‐Muro Dr. Patrick Trouillas Federico Giannini Dr. Julien Furrer Catherine M. Clavel Prof. Dr. Paul J. Dyson Prof. Dr. Georg Süss‐Fink Prof. Dr. Bruno Therrien 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(9):3198-3203
Hexanuclear thiolato‐bridged arene ruthenium metalla‐prisms of the general formula [(p‐cymene)6Ru6(SR)6(tpt)2]6+ (R=CH2Ph, CH2C6H4‐p‐tBu, CH2CH2Ph; tpt=2,4,6‐tris(4‐pyridyl)‐1,3,5‐triazine), obtained from the dinuclear precursors [(p‐cymene)2Ru2(SR)2Cl2], AgCF3SO3 and tpt, have been isolated and fully characterised as triflate salts. The metalla‐prisms are highly cytotoxic against human ovarian cancer cells, especially towards the cisplatin‐resistant cell line A2780cisR (IC50 <0.25 μM ). 相似文献