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941.
Kanematsu M Naumov P Kojima T Fukuzumi S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(44):12372-12384
The rate constants of intermolecular photoinduced electron transfer from triplet excited states of metalloporphyrins to a series of p-benzoquinone derivatives in benzonitrile were determined to examine the effects of the driving force, the metal, and the conformational distortion of the porphyrin ring on the reorganization energies (λ) of electron transfer by laser flash photolysis. The λ values were evaluated from the determined rate constants on the basis of the Marcus theory of electron transfer. The λ values of planar metalloporphyrins, [Al(TPP)(PhCOO)] and [Zn(TPP)] (TPP(2-)=tetraphenylporphyrin dianion), are approximately the same, but they are 0.27 eV smaller than those of the corresponding nonplanar (saddle-distorted) metalloporphyrins [Al(DPP)(PhCOO)] and [Zn(DPP)] (DPP(2-)=dodecaphenylporphyrin dianion) when they are compared for the same driving force of photoinduced electron transfer. The axial ligand PhCOO(-) of [Al(TPP)](+) and [Al(DPP)](+) was replaced by anthraquinone-2-carboxylate (AqCOO(-)) to afford the electron donor-acceptor complexes [Al(TPP)(AqCOO)] and [Al(DPP)(AqCOO)], respectively. The X-ray crystal structure of [Al(TPP)(AqCOO)] revealed strong coordination of AqCOO(-) to the Al(3+) ion of [Al(TPP)](+) and the existence of π-π interactions between AqCOO(-) and the porphyrin ring. In the case of the saddle-distorted [Al(DPP)(AqCOO)], however, the AqCOO(-) moiety is nearly perpendicular to the porphyrin ring. The photodynamics of intracomplex photoinduced electron transfer from the singlet excited state of [Al(TPP)](+) and [Al(DPP)](+) to the AqCOO(-) moiety were also examined in comparison with the intermolecular photoinduced electron-transfer reactions, and the determined rate constants were evaluated in light of the Marcus theory of electron transfer to reveal that the electron transfer is adiabatic in each case. 相似文献
942.
943.
Nishioka H Uesugi K Ueda N Kondo Y Tsuji M Abe H Harayama T Hamasaki T Baba M Takeuchi Y 《Chemical & pharmaceutical bulletin》2011,59(8):1075-1076
Optically active structural isomers (1b-f and dst-1b-f) of 3',4'-di-(O)-(-)-camphanoyl-(+)-khellactone (DCK) were synthesized and their anti-human immunodeficiency virus (HIV) activity was investigated. The value of the sensitivity index (SI) of 1b was greater than that of DCK. 相似文献
944.
Ariyasu S Hanaya K Tsunoda M Kitamura M Hayase M Abe R Aoki S 《Chemical & pharmaceutical bulletin》2011,59(11):1355-1362
Photochemical bond-cleavage reactions are potentially useful in chemistry, bioorganic chemistry and medicinal chemistry. We previously reported on a photochemical cleavage reaction of 8-quinolinyl sulfonate (8-QS) derivatives in aqueous solution at neutral pH, which we proposed to proceed via an excited triplet state. In this report, we report on the synthesis of some new photocleavable 8-QS derivatives, in which halogen atoms or a nitro group was introduced at the 7-position, in an attempt to improve photoreactive properties and to produce a red-shift in the irradiation wavelength. The introduction of bromine and iodine resulted in an acceleration in the photoreaction by about 1.5 times, possibly due to a heavy atom effect. It was also found that 7-nitro-8-QS absorbs at >360 nm, and, as a result, the S-O bond of this compound can be cleaved by photoirradiation with a fluorescent lamp in aqueous solution and on silicon surface. 相似文献
945.
Noguchi T Chikara C Kuroiwa K Kaneko K Kimizuka N 《Chemical communications (Cambridge, England)》2011,47(22):6455-6457
Supramolecular complexes consisting of anionic polyoxometalate (POM) and chiral, cationic lipids are newly developed. They give nanofibers, helical ribbons, and nanotapes in organic media depending on the chemical structure of lipid molecules. Lipid ammonium groups exert significant influence on their photoreduction characteristics. 相似文献
946.
Rai VK Nishiura M Takimoto M Hou Z 《Chemical communications (Cambridge, England)》2011,47(20):5726-5728
A neutral 2,2'-dipyridylamido (dpa)-supported bis(cyclometalated) iridium(III) complex [Ir(ppy)(2)(dpa)] (ppy = o-(2-pyridyl)phenyl) has been synthesized and structurally characterized for the first time, which emits green electroluminescence with high current efficiency (123.5 cd A(-1)) and high power efficiency (43.2 lm W(-1)). 相似文献
947.
Yutaro Sugiura Toshiyuki Takayanagi Masanori Tachikawa 《International journal of quantum chemistry》2020,120(22):e26376
The positron-electron correlation-polarization potential model is used to calculate annihilation spectra of carbon disulfide and benzene. We assume that the positron is captured in the vibrationally excited states of the target molecule through vibrational Feshbach resonances. Using the standard normal mode representation, we calculated the resonance energies and widths for each vibrational mode. The resonance widths were calculated with Fermi's Golden Rule approximation, where the time-dependent wave packet approach has been applied. We found that vibrational resonances of infrared-active modes play a dominant role in resonant annihilation; however, infrared-inactive modes also contribute to the annihilation spectrum through polarizability changes along normal mode coordinates. 相似文献
948.
Hiroyuki Nishide Naoki Yoshioka Takahiko Kaku Takashi Kaneko Masanori Yamazaki Eishun Tsuchida 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11-12):1177-1187
Synthesis and magnetic properties of π-conjugated stable polyradicals bearing a polyacetylene backbone are described. 2,6-Di-tert-butyl-4-ethynylphenol (8) and 4-ethynylphenylhydrogalvinoxyl (9) are polymerized with W, Mo chloride or Rh complex to yield their polyacetylene derivatives with molecular weight of ca. 104, while 2-ethynylphenalenone (10) gives only its oligomer. The polymers are soluble in common solvents and converted to the corresponding conjugated polyradicals via heterogeneous chemical oxidation using PbO2 or alkaline K3Fe(CN)6. The polyradicals with extremely high spin concentration (up to 4.8 × 1023 spins/monomer mol) are obtained by regulating the oxidative conditions. The polyradicals are quite stable in solution and even in the solid state because of resonance stabilization and/or a steric effect of the substituents. Magnetic interactions between the unpaired spins in the conjugated stable polyradicals are discussed. 相似文献
949.
Akihiko Toda Ken Taguchi Kano Sato Koji Nozaki Masanori Maruyama Katsuharu Tagashira Misuzu Konishi 《Journal of Thermal Analysis and Calorimetry》2013,113(3):1231-1237
Melting kinetics of it-polypropylene crystals has been examined over wide heating rates of 0.6 K min?1?104 K s?1 using a standard DSC and a fast-scan DSC. With fast-scan DSC, we have an access to the melting of crystals obtained at low temperatures, which are susceptible to re-organization at the heating rates applicable with standard DSC. It is clearly discernible that the appearance and disappearance of multiple melting peaks are strongly influenced by the applied heating rates and dependent on the crystallization temperatures. By examining the heating rate dependence of superheating of melting, we have determined the melting points of as-grown crystals formed under wide crystallization temperatures. 相似文献
950.
Yuhei Ishizaka Yuki Kawaguchi Kunimasa Saitoh Masanori Koshiba 《Optics Communications》2011,284(14):3528-3533
We propose a novel ultra-compact all-optical XOR and AND logic gates without using nonlinear optics. In order to realize these devices, we adopt photonic crystal waveguides (PCWs) based on multi-mode interference devices. Numerical results show that the operating bandwidth of the ON to OFF logic-level contrast ratio of not less than 6.79 dB is 35 nm for XOR logic gate and 9 nm for AND logic gate. Proposed logic gates have the potential to be key components for an optical packet switching system due to their small feature sizes and low power consumption. 相似文献