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841.
Hikaru Yanai Takumi Suzuki Florian Kleemiss Haruhiko Fukaya Yasuo Dobashi Lorraine A. Malaspina Simon Grabowsky Takashi Matsumoto 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(26):8931-8936
1,1‐Diamino‐2,2‐bis(triflyl)ethylenes with both twisted and planar structures around the partial “C=C” bond were synthesised. Bonding properties in these compounds were analysed by an experimental approach using high‐resolution X‐ray diffraction data treated with X‐ray wavefunction refinement (XWR). In the twisted compound, a dominant contribution of the charge‐separated resonance structure was revealed. On the contrary, the nearly planar compound still showed π‐bonding character, however, with a considerable contribution of the charge‐separated resonance structure. 相似文献
842.
Xin Wang Takashi Hisatomi Zheng Wang Jun Song Junle Qu Tsuyoshi Takata Kazunari Domen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(31):10776-10780
LaTaON2 is a photocatalyst with intense visible light absorption up to 650 nm, but exhibits low H2 evolution activity owing to uncontrolled facets and high defect densities. In this work, core–shell‐structured plate‐like LaKNaTaO5/LaTaON2 was synthesized by nitriding a layered perovskite‐type LaKNaTaO5. The volatilization of K and Na species during the nitridation promoted the rapid transformation of LaKNaTaO5 into LaTaON2 along [010] direction with the plate‐like shape retained. This yielded high‐quality LaTaON2 shells exposing (010) facets on the lattice‐matched LaKNaTaO5 cores. After loading with a Rh co‐catalyst, LaKNaTaO5/LaTaON2 showed photocatalytic H2 evolution activity four times greater than that obtained from conventional irregular‐shaped LaTaON2 powders and utilized visible light up to 620 nm. This work provides a novel strategy yielding oxynitrides with well‐defined facets and low defect densities by selecting lattice‐matched oxide precursors containing volatile components. 相似文献
843.
844.
Recently, we introduced an orbital-invariant approximate coupled-cluster (CC) method in the spin-projection manifold. The multi-determinantal property of spin-projection means that the parametrization in the spin-extended CC (ECC) ansatz is nonorthogonal and overcomplete. Therefore, the linear dependencies must be removed by an orthogonalization procedure to obtain meaningful solutions. Multi-reference methods often achieve this by diagonalizing a metric of the equation system, but this is not feasible with ECC because of the enormous size of the metric, a consequence of the incomplete active space of the spin-projected Hartree–Fock reference. As a result, the applicability of ECC has been limited to small benchmark systems, for which the ansatz was shown to be superior to the configuration interaction and linearized approximations. In this article, we provide a solution to this problem that completely avoids the metric diagonalization by iteratively projecting out its null-space from the working equations. As the additional computational cost required for this iterative projection is only marginal, it greatly expands the application range of ECC. We demonstrate the potential of approximate ECC by studying the complete basis set limit of F2 and transition metal complexes such as NiO, Mn2, and [Cu2O2]2+ , which have all been hindered by the prohibitively large metric size. We also identify the potential inadequacy of the molecular orbitals given by spin-projected Hartree–Fock in some cases, and propose possible solutions. © 2018 Wiley Periodicals, Inc. 相似文献
845.
846.
Anjana Adhikari-Devkota Sara Mustafa Idris Elbashir Takashi Watanabe 《Natural product research》2019,33(11):1670-1673
Flowers of Citrus plants are used as mild sedatives and for the treatment of insomnia in traditional medicines. In Japan, tea made from the flowers of Satsuma mandarin is consumed as healthy drink. Hesperidin (1), hesperetin (2), rutin (3), quercetin (4), nicotiflorin (5), eriocitrin (6), narirutin (7), phenylethyl glucoside (8) and unshuoside A (9) were isolated from the MeOH extract of fresh flowers. Structure elucidation of these compounds was performed on the basis of NMR spectroscopic data. Among them, rutin (3), quercetin (4) and eriocitrin (6) showed potent free radical scavenging activity, whereas hesperetin (2) and quercetin (4) showed potent α-glucosidase inhibitory activity. 相似文献
847.
Takashi Kaneta 《Chemical record (New York, N.Y.)》2019,19(2-3):452-461
Laser‐induced fluorometry (LIF) has achieved the detection of single molecules, which ranks it among the most sensitive of detection techniques, whereas capillary electrophoresis (CE) is known as a powerful separation method with resolution that is beyond the reach of many other types of chromatography. Therefore, a coupling of LIF with CE has established an unrivaled analytical technique in terms of sensitivity and resolution. CE‐LIF has demonstrated excellent performance in bioanalytical chemistry for the high‐resolution separation and highly sensitive detection of DNAs, proteins, and small bioactive molecules. This review describes the CE‐LIF methods developed by the author's group that include indirect and direct detection using diode lasers, post‐column derivatization, and Hadamard transformation, as well as applications to the binding assays of specific DNA immunoassays of proteins and to the determination of anticancer drugs. 相似文献
848.
Kosaka H Shigyou H Mitsumori Y Rikitake Y Imamura H Kutsuwa T Arai K Edamatsu K 《Physical review letters》2008,100(9):096602
We demonstrate that the superposition of light polarization states is coherently transferred to electron spins in a semiconductor quantum well. By using time-resolved Kerr rotation, we observe the initial phase of Larmor precession of electron spins whose coherence is transferred from light. To break the electron-hole spin entanglement, we utilized the big discrepancy between the transverse g factors of electrons and light-holes. The result encourages us to make a quantum media converter between flying photon qubits and stationary electron-spin qubits in semiconductors. 相似文献
849.
We have performed electroabsorption spectroscopy on micelle-wrapped single-wall carbon nanotubes. In semiconducting nanotubes, many oscillating structures composed of the increase and decrease of absorption are observed in the spectra in the region of the first and second absorption bands, E11 and E22. The spectral shape is reproduced mainly by the second-derivative curve of the absorption spectrum, which indicates the presence of nearly degenerate bright and dark excitonic states. 相似文献
850.
Takashi Uchida Masaya Tazawa Hiroshi Sakai Yoshihiro Kobayashi 《Applied Surface Science》2008,254(23):7591-7595
Radial breathing modes (RBMs) in resonance Raman spectra from single-walled carbon nanotubes (SWCNTs) on a SiO2/Si (0 0 1) substrate are studied between 25 and 720 °C. A change in the relative intensity of each RBM peak with temperature is observed, which originates from the temperature dependence of the resonance condition of nanotubes. For 25 °C, each RBM peak is reasonably assigned on the basis of data in the literature [J. Maultzsch, H. Telg, S. Reich, F. Hennrich, C. Thomsen, Phys. Rev. B 72 (2005) 205438]. By taking into account the temperature-dependent behavior of the relative intensity of the RBM peaks, each RBM peak is successfully assigned even for 720 °C. It is found that most of the observed RBM peaks for a laser excitation energy of Eexc = 1.96 eV are from chiral SWCNTs. These results make it possible to discuss further details of the chirality-dependent growth behavior observed for in situ Raman spectroscopy. 相似文献