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921.
The one-dimensional Klein-Gordon equation is solved for the PT-symmetric generalized Hulthén potential in the scalar coupling scheme. The relativistic bound-state energy spectrum and the
corresponding wave functions are obtained by using the Nikiforov-Uvarov method which is based on solving the second-order
linear differential equations by reduction to a generalized equation of hypergeometric type.
PACS numbers: 03.65.Fd, 03.65.Ge 相似文献
922.
Rafael de la Madrid 《International Journal of Theoretical Physics》2007,46(8):1986-1997
This paper is a contribution to the problem of particle localization in non-relativistic Quantum Mechanics. Our main results
will be (1) to formulate the problem of localization in terms of invariant subspaces of the Hilbert space, and (2) to show
that the rigged Hilbert space incorporates particle localization in a natural manner. 相似文献
923.
André Toom 《Journal of statistical physics》2007,129(3):555-566
We prove the existence of an invariant measure for a large class of random processes with discrete time without assuming their
linearity. Our main examples are “processes with variable length”, in which components may appear and disappear in the course
of functioning. One of these examples displays non-uniqueness of invariant measure in a 1-D process. 相似文献
924.
Shunlong Luo 《Journal of statistical physics》2007,128(5):1177-1188
The classical Fisher information is superadditive in the sense that the Fisher information of a bivariate probability density
is always not less than the sum of those of the marginals. The longstanding conjecture concerning the superadditivity of the
Wigner–Yanase–Dyson information is a quantum analogue of this property. It is remarkable that Hansen constructed a numerical
counterexample to the quantum case (J. Stat. Phys. 126: 643–648, 2007). However, the requirement of superadditivity of an information-theoretic quantity such as the Wigner–Yanase–Dyson information
seems so intuitive, it is desirable to identify conditions as general as possible such that the superadditivity holds. In
this paper, we establish the superadditivity in several physically significant cases. 相似文献
925.
Thomas Richthammer 《Communications in Mathematical Physics》2007,274(1):81-122
The conservation of translation as a symmetry in two-dimensional systems with interaction is a classical subject of statistical
mechanics. Here we establish such a result for Gibbsian particle systems with two-body interaction, where the interesting
cases of singular, hard-core and discontinuous interaction are included. We start with the special case of pure hard core
repulsion in order to show how to treat hard cores in general. 相似文献
926.
We previously reported that a deletion mutant (P478) with a residue Arg deleted at the C terminus of d-hydantoinase (P479) from Pseudomonas putida YZ-26 was dissociated into the monomer from its dimeric state. Based on the above result, a series of mutants of the enzyme
with the C-terminal residues either deleted or substituted were prepared. The size-exclusion chromatography and bioactivity
assay show that a C-terminal-substituted enzyme (R479D) and several truncated mutants (P478, P477, P476, and P475) are dissociated
into the monomeric state as well, but their activities are largely retained. In contrast, two other mutants (R474 and R479A)
are expressed in the form of random aggregates without any activity. Our experiments demonstrate that only the last four amino
acids (-PVQR) at the C terminus of the enzyme can be deleted without seriously affecting its activity, although the enzyme
is dissociated from a dimer into a monomer. These mutants also reveal some unique properties such as the enzymatic activity
in vivo or in vitro, the effect of divalent metal ions, and the thermostability etc. in comparison to wild-type enzyme (P479).
In addition, the three-dimensional structural modeling shows that the intact structure of the enzyme is essential, and the
flexibility of the non-conservative region at the C terminus of the enzyme is quite limited. 相似文献
927.
Resonance Raman spectroscopy of red blood cells using near-infrared laser excitation 总被引:5,自引:0,他引:5
Wood BR Caspers P Puppels GJ Pandiancherri S McNaughton D 《Analytical and bioanalytical chemistry》2007,387(5):1691-1703
Resonance Raman spectra of oxygenated and deoxygenated functional erythrocytes recorded using 785 nm laser excitation are
presented. The high-quality spectra show a mixture of enhanced A1g, A2g, B1g, B2g, Eu and vinyl modes. The high sensitivity of the Raman system enabled spectra from four oxygenation and deoxygenation cycles
to be recorded with only 18 mW of power at the sample over a 60-minute period. This low power prevented photo-/thermal degradation
and negated protein denaturation leading to heme aggregation. The large database consisting of 210 spectra from the four cycles
was analyzed with principal components analysis (PCA). The PC1 loadings plot provided exquisite detail on bands associated
with the oxygenated and deoxygenated states. The enhancement of a band at 567 cm−1, observed in the spectra of oxygenated cells and the corresponding PC1 loadings plot, was assigned to the Fe–O2 stretching mode, while a band appearing at 419 cm−1 was assigned to the Fe–O–O bending mode based on previous studies. For deoxygenated cells, the enhancement of B1g modes at 785 nm excitation is consistent with vibronic coupling between band III and the Soret transition. In the case of
oxygenated cells, the enhancement of iron-axial out-of-plane modes and non-totally symmetric modes is consistent with enhancement
into the y,z-polarized transition centered at 785 nm. The enhancement of non-totally symmetric B1g modes in oxygenated cells suggests vibronic coupling between band IV and the Soret band. This study provides new insights
into the vibrational dynamics, electronic structure and resonant enhancement of heme moieties within functional erythrocytes
at near-IR excitation wavelengths.
Part of this work was first presented at SPEC 2006, Shedding New Light on Disease: Optical Diagnosis for the New Millennium, held at Heidelberg, Germany, on 20–24 May 2006. 相似文献
928.
Paula Santos Nunes Marília Santos Bezerra L. P. Costa Juliana Cordeiro Cardoso R. L. C. AlbuquerqueJr. M. O. Rodrigues Gabriela Borin Barin Francilene Amaral da Silva A. A. S. Araújo 《Journal of Thermal Analysis and Calorimetry》2010,99(3):1011-1014
The purpose of this study was to evaluate the physical–chemical properties of collagen (CL) and usnic acid/collagen-based
(UAC) films, using differential thermal analysis (DTA), thermogravimetry (TG/DTG), infrared spectroscopy (FTIR), and scanning
electron microscopy (SEM). Both films were prepared by casting process using polyethylene glycol 1500 (PEG 1500) as plasticizer.
In the spectrum of UAC, similar bands of the usnic acid are observed, indicating that the polymerization (film formation)
did not affect the stability of the drug. Distinctly, DTA curve of UAC did not show an endothermic peak at 201 °C, indicative
that the drug was incorporated into the polymeric system. These results were corroborated by the scanning electron microscopy
(SEM). The TG/DTG curves of UAC presented a different thermal decomposition profile compared to the individual compounds and
CL. These findings suggest the occurrence of molecular dispersion or solubilization of the drug in the collagen film. 相似文献
929.
Zou X Liu D Zhong L Yang B Lou Y Hu B Yin Y 《Analytical and bioanalytical chemistry》2011,401(4):1251-1261
In this study, we describe a method for highly specific enrichment of phosphopeptides with multifunctional chitosan–glycidyl
methacrylate (GMA)–iminodiacetic acid (IDA)–Fe (III) nanospheres for direct analysis by matrix-assisted laser desorption–ionization
mass spectrometry (MALDI-MS). This is the first time that chitosan has been used to create nanospheres support material for
selective enrichment of phosphopeptides by modification with GMA, derivatization with IDA, and loading with Fe (III) ions.
Chitosan-GMA-IDA-Fe (III) nanospheres with a diameter of 20 to 100 nm have multifunctional chemical moieties which confer
unique properties, good dispersibility in highly acidic binding buffers, as well as good biocompatibility and chemical stability
which improves their specific interaction with phosphopeptides using various types of acid binding buffers. The process of
enrichment is very simple, quick, efficient, and specific. Its high specificity and efficiency for purification of phosphopeptides
is reflected in the very low and substoichiometric amounts of phosphopeptides which can be detected, in quantities as low
as 1:3,000 M ratios. Compared with other state-of the-art technologies such as the use of conventional Fe3+-IMAC and TiO2, these chitosan nanosphere techniques show superior specificity and sensitivity. Moreover, the resultant chitosan-GMA-IDA-Fe3+ nanosphere-absorbed phosphopeptides can be either directly analyzed by MALDI-TOF MS analysis or eluted and further analyzed
by nano-LC-MS/MS. 相似文献
930.
An electrospray ionization (ESI) ambient pressure ion-mobility spectrometer (APIMS) interfaced to an orthogonal reflector time-of-flight mass spectrometer (TOFMS) was evaluated for the first time as a detector for the identification of phenylthiohydantoin (PTH)-derivatized amino acids, the final products in the Edman sequencing process of peptides and proteins. The drift and flight times of the twenty common PTH amino acids were characterized by a well-defined 2-D mobility/mass spectral pattern. The combination of mobility/mass modes of analysis gave rise to a unique trend-line formation for the series of PTH amino acids. In addition, each PTH amino acid had a unique reduced mobility constant K(o), thus enabling the differentiation of all the amino acid derivatives including the PTH-leucine and PTH-isoleucine isomers. More importantly it was shown that it was possible to resolve a complete reference mixture of PTH amino acids in a single experimental run in less than 1 min. Detection limits for the PTH amino acids were found to range from 1.04 to 3.52 ng; indicating that the limits of detection were less than 17.0 pmol for all of the PTH amino acids. 相似文献