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31.
32.
Petra Bombicz Birger Dittrich Marianna Strumpel Hans‐Peter Nabein Peter Luger 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):1447-1449
The structure of glycyl‐dl ‐leucine, C8H16N2O3, has been determined at 120 K by single‐crystal X‐ray diffraction. In addition to three N—H?O‐type hydrogen bonds of the positively charged RNH3+ group of the zwitterionic molecule, an intermolecular N—H?O contact exists between the peptide bond and the carboxylate group. Four hydrogen‐bond cycles were identified, giving a complex pattern. 相似文献
33.
34.
Claudia M. Orben Birger Dittrich 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(6):580-583
For the structure of fluconazole [systematic name: 2‐(2,4‐difluorophenyl)‐1,3‐bis(1H‐1,2,4‐triazol‐1‐yl)propan‐2‐ol] monohydrate, C13H12F2N6O·H2O, a case study on different model refinements is reported, based on single‐crystal X‐ray diffraction data measured at 100 K with Cu Kα radiation to a resolution of sin θ/λ of 0.6 Å−1. The structure, anisotropic displacement parameters (ADPs) and figures of merit from the independent atom model are compared to `invariom' and `Hirshfeld atom' refinements. Changing from a spherical to an aspherical atom model lowers the figures of merit and improves both the accuracy and the precision of the geometrical parameters. Differences between results from the two aspherical‐atom refinements are small. However, a refinement of ADPs for H atoms is only possible with the Hirshfeld atom density model. It gives meaningful results even at a resolution of 0.6 Å−1, but requires good low‐order data. 相似文献
35.
B Andreasen DM Tanenbaum M Hermenau E Voroshazi MT Lloyd Y Galagan B Zimmernann S Kudret W Maes L Lutsen D Vanderzande U Würfel R Andriessen R Rösch H Hoppe G Teran-Escobar M Lira-Cantu A Rivaton GY Uzunoğlu DS Germack M Hösel HF Dam M Jørgensen SA Gevorgyan MV Madsen E Bundgaard FC Krebs K Norrman 《Physical chemistry chemical physics : PCCP》2012,14(33):11780-11799
The present work is the fourth (and final) contribution to an inter-laboratory collaboration that was planned at the 3rd International Summit on Organic Photovoltaic Stability (ISOS-3). The collaboration involved six laboratories capable of producing seven distinct sets of OPV devices that were degraded under well-defined conditions in accordance with the ISOS-3 protocols. The degradation experiments lasted up to 1830 hours and involved more than 300 cells on more than 100 devices. The devices were analyzed and characterized at different points of their lifetimes by a large number of non-destructive and destructive techniques in order to identify specific degradation mechanisms responsible for the deterioration of the photovoltaic response. Work presented herein involves time-of-flight secondary ion mass spectrometry (TOF-SIMS) in order to study chemical degradation in-plane as well as in-depth in the organic solar cells. Various degradation mechanisms were investigated and correlated with cell performance. For example, photo-oxidation of the active material was quantitatively studied as a function of cell performance. The large variety of cell architectures used (some with and some without encapsulation) enabled valuable comparisons and important conclusions to be drawn on degradation behaviour. This comprehensive investigation of OPV stability has significantly advanced the understanding of degradation behaviour in OPV devices, which is an important step towards large scale application of organic solar cells. 相似文献
36.
Christian B. Hübschle Birger Dittrich Peter Luger 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(9):o540-o542
In the title compound, C11H12N2O2·CH2O2, at 183 K. l ‐tryptophan appears in the zwitterionic form, while the formic acid molecule is neutral. The formic acid molecule is the donor in a strong O—H?O hydrogen bond to the carboxylate group of the tryptophan molecule, with a short O?O contact of 2.487 (2) Å. 相似文献
37.
Expanding the Landscape of Diterpene Structural Diversity through Stereochemically Controlled Combinatorial Biosynthesis 下载免费PDF全文
Dr. Johan Andersen‐Ranberg Dr. Kenneth Thermann Kongstad Dr. Morten Thrane Nielsen Dr. Niels Bjerg Jensen Dr. Irini Pateraki Dr. Søren Spanner Bach Britta Hamberger Prof. Dr. Philipp Zerbe Prof. Dr. Dan Staerk Prof. Dr. Jörg Bohlmann Prof. Dr. Birger Lindberg Møller Prof. Dr. Björn Hamberger 《Angewandte Chemie (International ed. in English)》2016,55(6):2142-2146
Plant‐derived diterpenoids serve as important pharmaceuticals, food additives, and fragrances, yet their low natural abundance and high structural complexity limits their broader industrial utilization. By mimicking the modularity of diterpene biosynthesis in plants, we constructed 51 functional combinations of class I and II diterpene synthases, 41 of which are “new‐to‐nature”. Stereoselective biosynthesis of over 50 diterpene skeletons was demonstrated, including natural variants and novel enantiomeric or diastereomeric counterparts. Scalable biotechnological production for four industrially relevant targets was accomplished in engineered strains of Saccharomyces cerevisiae. 相似文献
38.
Dr. Kartik Chandra Mondal Dr. Sudipta Roy Priv.‐Doz. Dr. Birger Dittrich Dr. Diego M. Andrada Prof. Dr. Gernot Frenking Prof. Dr. Herbert W. Roesky 《Angewandte Chemie (International ed. in English)》2016,55(9):3158-3161
Reduction of the neutral carbene tetrachlorosilane adduct (cAAC)SiCl4 (cAAC=cyclic alkyl(amino) carbene :C(CMe2)2(CH2)N(2,6‐iPr2C6H3) with potassium graphite produces stable (cAAC)3Si3, a carbene‐stabilized triatomic silicon(0) molecule. The Si?Si bond lengths in (cAAC)3Si3 are 2.399(8), 2.369(8) and 2.398(8) Å, which are in the range of Si?Si single bonds. Each trigonal pyramidal silicon atom of the triangular molecule (cAAC)3Si3 possesses a lone pair of electrons. Its bonding, stability, and electron density distributions were studied by quantum chemical calculations. 相似文献
39.
Birger Jansson 《BIT Numerical Mathematics》1964,4(1):6-27
In this paper some generating methods of the multiplicative and mixed congruential types for obtaining pseudo-random numbers are reviewed. Procedures to determine autocorrelations are demonstrated and a few numerical results are also given. 相似文献
40.
Electrolyte reduction products form the solid-electrolyte interphase (SEI) on negative electrodes of lithium-ion batteries. Even though this process practically stabilizes the electrode–electrolyte interface, it results in continued capacity-fade limiting lifetime and safety of lithium-ion batteries. Recent atomistic and continuum theories give new insights into the growth of structures and the transport of ions in the SEI. The diffusion of neutral radicals has emerged as a prominent candidate for the long-term growth mechanism, because it predicts the observed potential dependence of SEI growth. 相似文献