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231.
Inhomogeneous multidimensional cosmological models with a higher-dimensional space-time manifold
0
i=1
n Mi (n 1) are in stigated under dimensional reduction to a D
0-dimensional effective non-minimally coupled -model which generalizes the familiar Brans–Dicke model. The general form of the Einstein frame representation of multidimensional solutions known in the Brans–Dicke frame is given with respect to cosmic synchronous time. As an example, the transformation is demonstrated explicitly for the generalized Kasner solutions where it is shown that solutions in the Einstein frame show no inflation of the external space although they can undergo deflation after the cosmic synchronous time inversion. 相似文献
232.
Fernando Rinaldi Johannes Michael Ostermann Andrea Kroner Rainer Michalzik 《Optics Communications》2007,270(2):310-313
Vertical-cavity surface-emitting lasers (VCSELs) showing continuous-wave operation with emission wavelengths ranging between 717 and 790 nm have been fabricated. The samples are grown by solid source molecular beam epitaxy on GaAs substrates and are entirely based on the AlGaAs material system. A maximum single-mode output power of 2.0 mW is obtained at 754 nm wavelength by using the inverted surface relief technique. 相似文献
233.
Thomas Harmening Constanze M. Fehse Rainer Pöttgen 《Journal of solid state chemistry》2011,184(12):3303-3309
The silicides ScTSi (T=Fe, Co, Ni, Cu, Ru, Rh, Pd, Ir, Pt) were synthesized by arc-melting and characterized by X-ray powder diffraction. The structures of ScCoSi, ScRuSi, ScPdSi, and ScIrSi were refined from single crystal diffractometer data. These silicides crystallize with the TiNiSi type, space group Pnma. No systematic influences of the 45Sc isotropic magnetic shift and nuclear electric quadrupolar coupling parameters on various structural distortion parameters calculated from the crystal structure data can be detected. 45Sc MAS-NMR data suggest systematic trends in the local electronic structure probed by the scandium atoms: both the electric field gradients and the isotropic magnetic shifts relative to a 0.2 M aqueous Sc(NO3)3 solution decrease with increasing valence electron concentration and within each T group the isotropic magnetic shift decreases monotonically with increasing atomic number. The 45Sc nuclear electric quadrupolar coupling constants are generally well reproduced by quantum mechanical electric field gradient calculations using the WIEN2k code. 相似文献
234.
Frank Tappe Christian Schwickert Stefan Linsinger Rainer P?ttgen 《Monatshefte für Chemie / Chemical Monthly》2011,15(2):1087-1095
Abstract
The series of rare earth metal (RE)-rich intermetallics RE 4 TAl and RE 4 TIn (T = Ru, Rh, Ir) were synthesized by induction melting of the elements in sealed tantalum tubes. These compounds crystallize with the cubic Gd4RhIn-type structure, space group F[`4]3mF\bar{4}3m. The structures of eight crystals (including the isotypic compounds Ce4RuMg and Ce4RuCd) have been refined from X-ray single-crystal diffractometer data. The structures are composed of condensed RE 6 T trigonal prisms which form a rigid network with adamantane-like topology. Large cavities within these networks are filled with empty RE 6 octahedra and Al4, In4, Mg4, or Cd4 tetrahedra, respectively. Some of the RE 4 TAl and RE 4 TIn show small homogeneity ranges that result from small degrees of Al/T and In/T mixing on the 16e sites. All cerium compounds show small anomalies in the plots of the cell volumes. This is confirmed by temperature-dependent magnetic susceptibility measurements. Ce4RuMg, Ce4RuCd, Ce4RuAl, and Ce4RuIn show intermediate cerium valence and no magnetic ordering down to 3 K. Ce4RhAl shows essentially trivalent cerium. 相似文献235.
236.
237.
Dr. Carlo Fasting Prof. Christoph A. Schalley Dr. Marcus Weber Prof. Oliver Seitz Prof. Stefan Hecht Prof. Beate Koksch Dr. Jens Dernedde Prof. Christina Graf Prof. Ernst‐Walter Knapp Prof. Rainer Haag 《Angewandte Chemie (International ed. in English)》2012,51(42):10472-10498
Multivalent interactions can be applied universally for a targeted strengthening of an interaction between different interfaces or molecules. The binding partners form cooperative, multiple receptor–ligand interactions that are based on individually weak, noncovalent bonds and are thus generally reversible. Hence, multi‐ and polyvalent interactions play a decisive role in biological systems for recognition, adhesion, and signal processes. The scientific and practical realization of this principle will be demonstrated by the development of simple artificial and theoretical models, from natural systems to functional, application‐oriented systems. In a systematic review of scaffold architectures, the underlying effects and control options will be demonstrated, and suggestions will be given for designing effective multivalent binding systems, as well as for polyvalent therapeutics. 相似文献
238.
239.
Dirk Steinhilber Torsten Rossow Dr. Stefanie Wedepohl Florian Paulus Dr. Sebastian Seiffert Prof. Dr. Rainer Haag 《Angewandte Chemie (International ed. in English)》2013,52(51):13538-13543
pH‐Cleavable cell‐laden microgels with excellent long‐term viabilities were fabricated by combining bioorthogonal strain‐promoted azide–alkyne cycloaddition (SPAAC) and droplet‐based microfluidics. Poly(ethylene glycol)dicyclooctyne and dendritic poly(glycerol azide) served as bioinert hydrogel precursors. Azide conjugation was performed using different substituted acid‐labile benzacetal linkers that allowed precise control of the microgel degradation kinetics in the interesting pH range between 4.5 and 7.4. By this means, a pH‐controlled release of the encapsulated cells was achieved upon demand with no effect on cell viability and spreading. As a result, the microgel particles can be used for temporary cell encapsulation, allowing the cells to be studied and manipulated during the encapsulation and then be isolated and harvested by decomposition of the microgel scaffolds. 相似文献
240.
Wolfgang Scherer Prof. Dr. Christoph Hauf Dipl.‐Phys. Manuel Presnitz Dipl.‐Phys. Ernst‐Wilhelm Scheidt Dr. Georg Eickerling Dr. Volker Eyert Dr. Rolf‐Dieter Hoffmann Dr. Ute C. Rodewald Dipl.‐Ing. Adrienne Hammerschmidt Dr. Christian Vogt Dr. Rainer Pöttgen Prof. Dr. 《Angewandte Chemie (International ed. in English)》2010,49(9):1578-1582