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991.
Chemical reactivity of sc3n @ c80 and la2 @ c80 总被引:2,自引:0,他引:2
Iiduka Y Ikenaga O Sakuraba A Wakahara T Tsuchiya T Maeda Y Nakahodo T Akasaka T Kako M Mizorogi N Nagase S 《Journal of the American Chemical Society》2005,127(28):9956-9957
Sc3N@C80 has a lower thermal reactivity than La2@C80, although Sc3N@C80 has the same carbon cage (Ih) and oxidation state (C806-) as La2@C80. This result is attributed to the difference in the energy level and distribution of LUMO between Sc3N@C80 and La2@C80. 相似文献
992.
Takahiro Soma Toshio Shimizu Kazunori Hirabayashi Nobumasa Kamigata 《Heteroatom Chemistry》2007,18(3):301-311
2‐(Methylchalcogenomethyl)diphenyl selenoxides 1 and 2‐{2′‐(N,N‐dimethylamino)ethyl}phenyl alkyl (or aryl) selenoxides 2 , which were expected to be stabilized toward racemization by intramolecular coordination, were synthesized and optically resolved into their enantiomers on an optically active column using high‐performance liquid chromatography. Relationship between the absolute configurations and the chiroptical properties of the enantiomers was clarified by comparing with those of sulfur analogues. Stabilities toward racemization of optically active selenoxides 1a and 1b were nearly equal to that of 2‐{(N,N‐dimethylamino)methyl}diphenyl selenoxide and mesityl phenyl selenoxide. The rates of racemization for optically active selenoxides 2 were found to be faster than that of 2‐{(N,N‐dimethylamino)methyl}phenyl alkyl (or aryl) selenoxides. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:301–311, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20299 相似文献
993.
Yamada M Nakahodo T Wakahara T Tsuchiya T Maeda Y Akasaka T Kako M Yoza K Horn E Mizorogi N Kobayashi K Nagase S 《Journal of the American Chemical Society》2005,127(42):14570-14571
The exohedrally functionalized derivative of endohedral metallofullerene, Ce2@C80(Mes2SiCH2SiMes2), was successfully synthesized and fully characterized. X-ray crystallographic and NMR spectroscopic analyses reveal that the free random motion of two metal atoms in Ce2@C80 is controlled inside the cage by exohedral chemical functionalization. 相似文献
994.
Anomalous Freezing of Nano‐Confined Water in Room‐Temperature Ionic Liquid 1‐Butyl‐3‐Methylimidazolium Nitrate 下载免费PDF全文
Prof. Hiroshi Abe Dr. Takahiro Takekiyo Prof. Yukihiro Yoshimura Koji Saihara Prof. Akio Shimizu 《Chemphyschem》2016,17(8):1136-1142
Non‐crystal formation of ice is investigated by simultaneous X‐ray diffraction and differential scanning calorimetry measurements upon cooling to ?100 °C. At room temperature, size‐tunable water confinement (≈20 Å size) in a room‐temperature ionic liquid (RTIL, 1‐butyl‐3‐methylimidazolium nitrate, [C4mim][NO3]) exists in a water‐rich region (70–90 mol % D2O). The confined water (water pocket) is characterized by almost monodispersive size distribution. In [C4mim][NO3]‐x mol % D2O (70<x<94), the absence of sharp Bragg reflections and a distinct exothermal peak indicate that crystallization/cold crystallization both of [C4mim][NO3] and D2O is suppressed, even upon slow cooling and heating. 相似文献
995.
Akira Adachi Joji Ohshita Takahiro Ohno Atsutaka Kunai Stefan A. Manhart Koichi Okita Junji Kido 《应用有机金属化学》1999,13(12):859-865
Double‐layer electroluminescent (EL) devices composed of an alternating polymer with mono‐, di‐, or tri‐silanylene and phenylene units, [(Si R) m (C6H4)] n (R = alkyl, m = 1–3) as a hole‐transporting layer, and tris(8‐quinolinolato)aluminium(III) complex (Alq) as an electron‐transporting–emitting layer were fabricated. The longer silanylene chain lengths in the polymer, on going from m = 1 to m = 2 and 3, result in better electrical properties for the EL devices, implying that the σ–π conjugation in the polymers plays an important role in the hole‐transporting properties, including the hole‐injection efficiency from an anode. This is in marked contrast to the improved hole‐transporting properties that occur in response to reducing the silanylene chain length of silanylene‐diethynylanthracene polymers previously reported. The UV absorption maxima of silanylene‐phenylene polymers shift to longer wavelengths with increasing m, and their oxidation peak potentials in cyclic voltammograms shift to lower potential with increasing m, in accordance with the improved electrical properties of the device that are observed with the polymers containing the longer silanylene chain. A triple‐layer EL device with a hole‐transporting layer of monosilanylene‐diethynylanthracene polymer, an electron‐transporting–emitting layer of Alq, and an electron‐blocking layer of N,N′‐diphenyl‐N,N′‐bis(3‐methylphenyl)‐1,1′‐biphenyl‐4,4′‐diamine (TPD) exhibited a maximum efficiency of 1.0 lm W−1 and a maximum luminance of 14750 cd m−2, both of which are much higher than the values obtained from a conventional EL device with TPD/Alq. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
996.
Takahiro Sugimoto Yuichi Tateishi Yoshihisa Sei Seiji Shinkai 《Tetrahedron letters》2005,46(32):5347-5350
A new strategy to control the orientation and aggregation numbers of porphyrins by alignment along well-defined templates has been demonstrated. Porphyrin-bridged bisPYBOX ligands were arranged along the oligomeric secondary dialkylammonium cations as templates to form well-defined supramolecular complexes. The templates controlled the aggregations of the porphyrins. 相似文献
997.
Kiyoshi Endo Takahiro Kitagawa Kenji Nakatani 《Journal of polymer science. Part A, Polymer chemistry》2006,44(13):4088-4094
The effect of an alkyl substituted in the aromatic ring of the salen ligand on the polymerization of butadiene (Bd) with (salen)Co(II) complexes in combination with methylaluminoxane (MAO) was investigated. The activity for the polymerization of Bd was influenced significantly by the introduction of alkyl groups at the 3,3′,5,5′‐positions in the aromatic ring of the salen ligand, and both the polymerization rate and 1,4‐cis contents increased in the following order with respect to the alkyl group: H < CH3 < t‐C4H9. This is in good agreement with the bulkiness of the alkyl groups. The activity for the polymerization of the (salen)Co(II) complex possessing t‐C4H9 at the 3,3′‐positions was higher than that of the (salen)Co(II) bearing t‐C4H9 at the 5,5′‐positions. Thus, the introduction of bulky substituents at the 3,3′‐positions of the salen ligand was an important factor in achieving both high activity and high 1,4‐cis selectivity in the polymerization of Bd with (salen)Co(II) complexes in combination with MAO. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4088–4094, 2006 相似文献
998.
Using an in situ pulsed laser photolysis/pulsed laser‐induced fluorescence/technique, the OH reaction kinetics of a three‐ring polycyclic aromatic hydrocarbon (PAH), phenanthrene (and its deuterated form), was investigated over the temperature range of 373–1000 K. This study represents the first examination of the OH kinetics for phenanthrene at elevated temperatures using the absolute rate technique. The phenanthrene results indicate a temperature dependence similar to its isomer anthracene, reported previously in R. Ananthula, T. Yamada, and P. H. Taylor, J Phys Chem A 2006, 100, 3559–3566, over a similar temperature range. The phenanthrene rate constants are similar to anthracene at high temperature (ca. 1000 K) and a factor of ca. 2 lower at low temperatures (373–700 K). The rate measurements were best fitted by the following two‐parameter expression of the form ATn: k1(373–1000 K) = 4.98 ± 2.96 × 10?6 * T?1.97±0.10 (in units of cm3 molecule?1 s?1, error limits ±1σ). Rate measurements with deuterated phenanthrene below 725 K were indistinguishable from the phenanthrene rate measurements, within random error limits, providing strong evidence for an OH‐addition mechanism. The effects of PAH size on their reactivity with OH radicals based on selected data over the temperature range of 243–1200 K are discussed. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 629–637, 2007 相似文献
999.
1000.
Yuichi Ito Takahiro Shimada Jaekook Ha Martin Vacha Hisaya Sato 《Journal of polymer science. Part A, Polymer chemistry》2006,44(14):4338-4345
We report the preparation of a new electroluminescent polymer by the oxidative coupling copolymerization of N‐(4‐n‐butylphenyl)phenoxazine and 9,9‐di‐n‐butylfluorene with ferric(III) chloride. The reaction yields soluble polymers with a weight‐average molecular weight as high as 9000. The reactivity has been studied with respect to the reaction time, temperature, and feed ratio of the comonomers. Under optimum conditions, a copolymer with a 50% comonomer incorporation ratio can be obtained in a 75% yield. The polymers have been characterized with differential scanning calorimetry, cyclic voltammetry, and optical spectroscopy. A simple single‐layer light‐emitting‐diode device of an indium tin oxide/polymer/Mg–Ag structure shows a luminance of 200 cd/m2 at an 18‐V operating voltage. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4338–4345, 2006 相似文献