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201.
Braunschweig H Damme A Gamon D Kelch H Krummenacher I Kupfer T Radacki K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(27):8430-8436
We describe the synthesis of base-free bisborole [Cym(?)(BC(4)Ph(4))(2)]-Cym(?)=(OC)(3)Mn(η(5)-C(5)H(3))-and its transformation into two fully characterized Lewis acid-base adducts with pyridine bases of the type 4-R-NC(5)H(4) (R=tBu, NMe(2)). The results of electrochemical, as well as NMR and UV/Vis spectroscopic studies on [Cym(?)(BC(4 Ph(4))(2)] and the related monoborole derivative [Cym(BC(4)Ph(4))]-Cym=(OC)(3)Mn(η(5)-C(5) H(4))-provided conclusive evidence for 1) the enhanced Lewis acidity of the two boron centers that result from conjugation of two borole fragments, and 2) the fact that Mn-B bonding interactions between the Lewis acidic borole moieties and the Mn center are considerably less pronounced for bisborole [Cym(?)(BC(4)Ph(4))(2)]. In addition, the reduction chemistry of [Cym(?)(BC(4)Ph(4))(2)] has been studied in detail, both electrochemically and chemically. Accordingly, chemical reduction of [Cym(?)(BC(4)Ph(4))(2)] with magnesium anthracene afforded the corresponding tetraanion, which features a rare Mg-OC bonding mode in the solid state. 相似文献
202.
Prof. Dr. Holger Braunschweig Alexander Damme Dr. Daniela Gamon Hauke Kelch Dr. Ivo Krummenacher Dr. Thomas Kupfer Dr. Krzysztof Radacki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(27):8430-8436
We describe the synthesis of base‐free bisborole [Cym?(BC4Ph4)2]—Cym?=(OC)3Mn(η5‐C5H3)—and its transformation into two fully characterized Lewis acid–base adducts with pyridine bases of the type 4‐R? NC5H4 (R=tBu, NMe2). The results of electrochemical, as well as NMR and UV/Vis spectroscopic studies on [Cym?(BC4Ph4)2] and the related monoborole derivative [Cym(BC4Ph4)]—Cym=(OC)3Mn(η5‐C5H4)—provided conclusive evidence for 1) the enhanced Lewis acidity of the two boron centers that result from conjugation of two borole fragments, and 2) the fact that Mn? B bonding interactions between the Lewis acidic borole moieties and the Mn center are considerably less pronounced for bisborole [Cym?(BC4Ph4)2]. In addition, the reduction chemistry of [Cym?(BC4Ph4)2] has been studied in detail, both electrochemically and chemically. Accordingly, chemical reduction of [Cym?(BC4Ph4)2] with magnesium anthracene afforded the corresponding tetraanion, which features a rare Mg? OC bonding mode in the solid state. 相似文献
203.
Checco A Schollmeyer H Daillant J Guenoun P Boukherroub R 《Langmuir : the ACS journal of surfaces and colloids》2006,22(1):116-126
We report on a novel technique to nucleate nanometer-sized droplets on a solid substrate and to image them with minimal perturbation by noncontact atomic force microscopy (NC-AFM). The drop size can be accurately controlled, thus permitting hysteresis measurements. We have studied the nanoscale wettability of several methyl-terminated substrates prepared by the self-assembly of organic molecules. These substrates are alkyltrichlorosilanes on silica, alkylthiols on gold, alkyl chains on hydrogen-terminated silicon, and crystalline hexatriacontane chains on silica. For each of these systems, we report a deviation of the wetting contact angle from the macroscopic value, and we discuss this effect in term of mesoscale surface heterogeneity and long-range solid-liquid interactions. 相似文献
204.
We study the extended Bose-Hubbard model describing an ultracold gas of dipolar molecules in an optical lattice, taking into account all on-site and nearest-neighbor interactions, including occupation-dependent tunneling and pair tunneling terms. Using exact diagonalization and the multiscale entanglement renormalization ansatz, we show that these terms can destroy insulating phases and lead to novel quantum phases. These considerable changes of the phase diagram have to be taken into account in upcoming experiments with dipolar molecules. 相似文献
205.
Hauke Paulsen Ventzislav Rusanov Ruediger Benda Christian Herta Volker Schuenemann Christoph Janiak Thomas Dorn Aleksandr I. Chumakov Heiner Winkler Alfred X. Trautwein 《ChemInform》2002,33(26):no-no
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
206.
207.
Silvia De Sio Jana Waegele Twinkle Bhatia Bruno Voigt Hauke Lilie Maria Ott 《Macromolecular bioscience》2023,23(7):2200527
Amyloid β (Aβ) is the major constituent in senile plaques of Alzheimer's disease in which peptides initially undergo structural conversions to form elongated fibrils. The impact of crowding on the fibrillation pathways of Aβ40 and Aβ42, the most common peptide isoforms are studied. PEG and Ficoll are used as model crowders to mimic a macromolecular enriched surrounding. The fibrillar growth is monitored with the help of ThT-fluorescence assays in order to extract two rates describing primary and secondary processes of nucleation and growth. Techniques as fluorescence correlation spectroscopy and analytical ultracentrifugation are used to discuss oligomeric states; fibril morphologies are investigated using negative-staining transmission electron microscopy. While excluded volume effects imposed by macromolecular crowding are expected to always increase rates of intermolecular interactions and structural conversion, a vast variety of effects are found depending on the peptide, the crowder, or ionic strength of the solution. While investigations of the obtained rates with respect to a reactant-occluded model are capable to display specific surface interactions with the crowder, the employment of crystallization-like models reveal the crowder-induced entropic gain with J mol−1 per volume fraction of the crowder. 相似文献
208.
Xin Liu Bowen Yang Dr. Xin Zhou Dr. Mingjian Wu Prof. Dr. Erdmann Spiecker Prof. Dr. Julien Bachmann Dr. Frank Hauke Prof. Dr. Andreas Hirsch Dr. Tao Wei 《Angewandte Chemie (International ed. in English)》2023,62(47):e202314183
Three-dimensionally (3D) well-ordered and highly integrated graphene hybrid architectures are considered to be next-generation multifunctional graphene materials but still remain elusive. Here, we report the first realization of unprecedented 3D-patterned graphene nano-ensembles composed of a graphene monolayer, a tailor-made structured organophenyl layer, and three metal oxide films, providing the first example of such a hybrid nano-architecture. These spatially resolved and hierarchically structured quinary hybrids are generated via a two-dimensional (2D)-functionalization-mediated atomic layer deposition growth process, involving an initial lateral molecular programming of the graphene lattice via lithography-assisted 2D functionalization and a subsequent stepwise molecular assembly in these regions in the z-direction. Our breakthrough lays the foundation for the construction of emerging 3D-patterned graphene heterostructures. 相似文献