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881.
882.
Catherina Gasser Isabel Delazer Eva Neuner Katharina Pascher Karl Brillet Sarah Klotz Lukas Trixl Maximilian Himmelstoß Eric Ennifar Dietmar Rieder Alexandra Lusser Ronald Micura 《Angewandte Chemie (International ed. in English)》2020,59(17):6881-6886
Temporal information about cellular RNA populations is essential to understand the functional roles of RNA. We have developed the hydrazine/NH4Cl/OsO4‐based conversion of 6‐thioguanosine (6sG) into A′, where A′ constitutes a 6‐hydrazino purine derivative. A′ retains the Watson–Crick base‐pair mode and is efficiently decoded as adenosine in primer extension assays and in RNA sequencing. Because 6sG is applicable to metabolic labeling of freshly synthesized RNA and because the conversion chemistry is fully compatible with the conversion of the frequently used metabolic label 4‐thiouridine (4sU) into C, the combination of both modified nucleosides in dual‐labeling setups enables high accuracy measurements of RNA decay. This approach, termed TUC‐seq DUAL, uses the two modified nucleosides in subsequent pulses and their simultaneous detection, enabling mRNA‐lifetime evaluation with unprecedented precision. 相似文献
883.
Lukas Biesen Nithiya Nirmalananthan‐Budau Katrin Hoffmann Ute Resch‐Genger Thomas J. J. Müller 《Angewandte Chemie (International ed. in English)》2020,59(25):10037-10041
N‐Benzyl aroyl‐S,N‐ketene acetals can be readily synthesized by condensation of aroyl chlorides and N‐benzyl 2‐methyl benzothiazolium salts in good to excellent yields, yielding a library of 35 chromophores with bright solid‐state emission and aggregation‐induced emission characteristics. Varying the substituent from electron‐donating to electron‐withdrawing enables the tuning of the solid‐state emission color from deep blue to red. 相似文献
884.
Henrik Müller Ann‐Kristin Becker Gottfried J. Palm Leona Berndt Christoffel P. S. Badenhorst Simon P. Godehard Lukas Reisky Michael Lammers Uwe T. Bornscheuer 《Angewandte Chemie (International ed. in English)》2020,59(28):11607-11612
Certain hydrolases preferentially catalyze acyl transfer over hydrolysis in an aqueous environment. However, the molecular and structural reasons for this phenomenon are still unclear. Herein, we provide evidence that acyltransferase activity in esterases highly correlates with the hydrophobicity of the substrate‐binding pocket. A hydrophobicity scoring system developed in this work allows accurate prediction of promiscuous acyltransferase activity solely from the amino acid sequence of the cap domain. This concept was experimentally verified by systematic investigation of several homologous esterases, leading to the discovery of five novel promiscuous acyltransferases. We also developed a simple yet versatile colorimetric assay for rapid characterization of novel acyltransferases. This study demonstrates that promiscuous acyltransferase activity is not as rare as previously thought and provides access to a vast number of novel acyltransferases with diverse substrate specificity and potential applications. 相似文献
885.
Charan Krishna Nichenametla Jesus Calvo Stefan Riedel Lukas Gerlich Meike Hindenberg Sergej Novikov Alexander Burkov Primož Kozelj Raul Cardoso-Gil Maik Wagner-Reetz 《无机化学与普通化学杂志》2020,646(14):1231-1237
Abstract . We report on semi-metallic cobalt monosilicide (CoSi) as a CMOS-compatible thermoelectric (TE) material and discuss the effect of n- and p-type dopants on its transport properties. Thin films of CoSi are developed using chemical vapor deposition tools and subsequent rapid thermal processing. Film properties such as microstructure, crystallinity and elemental distribution are studied via electron microscopy, X-ray diffraction and time-of-flight secondary ion mass spectroscopy. Doping silicon with boron prior to silicidation impedes the Co-Si diffusion process, while phosphorus atoms distribute uniformly in silicides with no voids or agglomerations. CoSi makes a suitable n-type TE candidate and provides an alternative to Si or SiGe materials. Transport properties of undoped CoSi exhibit a linear dependence within the investigated temperature window, whereas dopants in CoSi increase the number of electron carriers that contribute to charge transport and thereby influence the Seebeck coefficient. Thus, TE characteristics of thin CoSi films can be tuned via (i) the type of dopants used and/or (ii) varying the residual silicon thickness post silicidation. 相似文献
886.
Dr. Maxime Debost Dr. Paul B. Klar Dr. Nicolas Barrier Dr. Edwin B. Clatworthy Dr. Julien Grand Dr. Fabien Laine Dr. Petr Brázda Dr. Lukas Palatinus Dr. Nikolai Nesterenko Dr. Philippe Boullay Dr. Svetlana Mintova 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(52):23697-23701
Small-pore zeolites such as chabazite (CHA) are excellent candidates for the selective separation of CO2; however, the current synthesis involves several steps and the use of organic structure-directing agent (OSDA), increasing their cost and energy requirements. We report the synthesis of small-pore zeolite crystals (aluminosilicate) with CHA-type framework structure by direct synthesis in a colloidal suspension containing a mixture of inorganic cations only (Na+, K+, and Cs+). The location of CO2 molecules in the host structure was revealed by 3D electron diffraction (3D ED). The high sorption capacity for CO2 (3.8 mmol g−1 at 121 kPa), structural stability and regenerability of the discreate CHA zeolite nanocrystals is maintained for 10 consecutive cycles without any visible degradation. The CHA zeolite (Si:Al=2) reaches an almost perfect CO2 storage capacity (8 CO2 per unit cell) and high selectivity (no CH4 was adsorbed). 相似文献
887.
Dr. Romain Costil Dr. Stefano Crespi Dr. Lukas Pfeifer Prof. Dr. Ben L. Feringa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(35):7783-7787
The preparation, assembly and dynamic properties of photoswitchable bisphosphine ligands based on the stiff-stilbene scaffold are reported. Directional bonding and coordination-induced assembly allow complexation of these ligands with palladium(II), resulting in the formation of discrete metallo-supramolecular entities. While the Z isomer forms a simple bidentate metallo-macrocycle, an intricate double helicate figure-of-eight dimer is observed with the E ligand. Topologically 3D complexes can thus be obtained from 2D ligands. Upon irradiation with UV light, isomerization of the ligands allows control of the architecture of the formed complexes, resulting in a light-triggered modulation of the supramolecular topology. Furthermore, a mechanistic investigation unveiled the dynamic nature of the helicate chirality, where a transmission of motion from the palladium centers yields an „eight-to-eight“ inversion. 相似文献
888.
Malte Gallhof Lukas Kell Prof. Malte Brasholz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(8):1772-1775
Ruthenium(II) alkylidene complexes such as the Grubbs’ 1st and 2nd generation catalysts undergo a ligand substitution with 2,2′-bipyridine, which readily leads to the common photoredox catalyst Ru(bpy)32+. The application of this catalyst transformation in sequential olefin metathesis/photoredox catalysis is demonstrated by way of ring-closing metathesis (RCM)/photoredox ATRA reactions. 相似文献
889.
Philippe Klein Vivien Denise Lechner Tanja Schimmel Prof. Dr. Lukas Hintermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(1):176-180
The generation of arylzinc reagents (ArZnX) by direct insertion of zinc into the C−X bond of ArX electrophiles has typically been restricted to iodides and bromides. The insertions of zinc dust into the C−O bonds of various aryl sulfonates (tosylates, mesylates, triflates, sulfamates), or into the C−X bonds of other moderate electrophiles (X=Cl, SMe) are catalyzed by a simple NiCl2–1,4-diazadiene catalyst system, in which 1,4-diazadiene (DAD) stands for diacetyl diimines, phenanthroline, bipyridine and related ligands. Catalytic zincation in DMF or NMP solution at room temperature now provides arylzinc sulfonates, which undergo typical catalytic cross-coupling or electrophilic substitution reactions. 相似文献
890.
Johannes Bayer Jan Herberger Lukas Holz Prof. Dr. Rainer F. Winter Dr. Thomas Huhn 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(72):17546-17558
C−C cross coupling products of bowl-shaped as-indaceno[3,2,1,8,7,6-pqrstuv]picene (Idpc) and different planar arenes and ethynyl-arenes were synthesized. Photoluminescence as well as electrochemical properties of all products were investigated and complemented by time-dependent quantum chemical calculations. UV/Vis spectroelectrochemistry investigations of the directly linked (Idpc)2 indicated the absence of any intramolecular charge-transfer transition of intermittently formed (Idpc)2.−. All coupling products showed fluorescence. Ferrocene-1-yl-Idpc was structurally characterized by X-ray diffraction and is a rare example of a ferrocene-containing buckybowl exhibiting luminescence. 相似文献