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121.
Kiyoshi Ozawa Yoshio Sakka Muneyuki Amano 《Journal of Sol-Gel Science and Technology》2000,19(1-3):595-598
Cubic antimonic acid (Sb2O5·nH2O) films were successfully prepared on stainless steel and Si(100) substrates by electrophoretic deposition (EPD) using two types of sols. The sols were prepared by reacting an H2O2 aqueous solution with Sb(O-i-C3H7)3 or metallic Sb powder. The resulting films were found to consist of fine particles of cubic Sb2O5·nH2O single crystals with uniform particle sizes of 30 nm and 150 nm. The weight of the Sb2O5·nH2O deposit on the anode Si(100) substrate by EPD increased linearly with the current density in the range of 0–0.67 mA cm–2, when the sol pH was over 7. The proton conductivity of the polycrystalline Sb2O5·nH2O discs, formed from the two types of sols, was evaluated by an ac impedance method at room temperature under controlled levels of relative humidity. 相似文献
122.
A novel conjugation-elongated bis(ethylenedithio)tetraselenafulvalene (BETS) type donor, 2,5-bis(4,5-ethylenedithio-1,3-diselenol-2-ylidene)-2,3,4,5-tetrahydrothiophene (BEDT-HBDST) and its magnetic and non-magnetic anion salts, (BEDT-HBDST)2MX4 (MX4−=FeCl4−, GaCl4−, FeBr4− and GaBr4−), were prepared. These four salts are isostructural and belong to the space group of P2/c. They showed semiconducting behavior with small activation energies (59-64 meV). The band structures of these salts are quasi one-dimensional and there is a midgap between the upper band and the lower band, since the degree of dimerization is significant in the stacking direction. The MX4− ions are located between the donor columns and near to the ethylenedithio moieties of the donor molecules. The magnetic susceptibilities of the FeCl4− and FeBr4− salts follow the Curie-Weiss law with Curie constants of 4.6 and 4.8 emu K mol−1 (sum of the spins of S=5/2 and S=1/2) and negative Weiss temperatures of θ=−1.2 and −4.9 K, respectively, revealing a weak antiferromagnetic interaction of 3d spins of the FeCl4− and FeBr4− anions. The Fe?Fe (6.66-7.60 Å), Cl?Cl (4.81-4.82 Å) and Br?Br (4.74-4.77 Å) distances in the crystal structures of these salts are significantly long. Therefore, the direct magnetic interaction between the 3d spins of the nearest neighboring Fe3+ ions appears to be not readily accessible. 相似文献
123.
E. I. Zhilyaeva S. A. Torunova R. N. Lyubovskaya R. B. Lyubovskii 《Russian Chemical Bulletin》1996,45(5):1107-1110
Radical cation salts with halide mercurate anions were obtained by the electrochemical oxidation of bis(ethylenedioxo)tetrathiafulvalene (BEDO-TTF), and their conductivity was studied. The compounds (BEDO-TTF)4Hg3X8 (X = Cl or Br), (BEDO-TTF)4Hg3.5I9, and (BEDO-TTF)2HgBr3 possess the conductivity of the metallic type down to helium temperatures.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1167–1170, May, 1996. 相似文献
124.
Novel Fast Ion Conductors of the Type M MIIICl6 (MI = Li, Na, Ag; MIII = In, Y) The ternary chlorides Li3InCl6, Na3InCl6, Ag3InCl6, and Li3YCl6 have been studied by difference scanning calorimetry, high-temperature X-ray, infrared, and high-temperature Raman methods. Impedance spectroscopic measurements exhibit fast ionic conductivity increasing in the sequence Na3InCl6 < Li3YCl6 < Ag3InCl6 < Li3InCl6. In the range of 300°C, Li3InCl6 is the best lithium ion conductor known so far (σ = 0,2 Ω?1 cm?1 at 300°C). With the exception of Na3InCl6, the chlorides exhibit complicated order-disorder phase transitions. 相似文献
125.
Band structure calculations at the level of LMTO-ASA provide insight into the electronic structure of BaV10O15 and the origin of the structural phase transition. A crystal orbital Hamiltonian population/integrated crystal orbital Hamiltonian population analysis provides evidence that the crystallographic phase transition is driven by V-V bond formation. As well, the energy bands near the Fermi level are very narrow, <1 eV, consistent with the fact that the observed insulating behavior can be due to electron localization via either Mott-Hubbard correlation and/or Anderson disorder. The partial solid solution, BaV10−xTixO15, was examined to study the effect of Ti-doping at the V sites on the structure and electronic transport properties. In spite of the non-existence of “BaTi10O15”, the limiting x=8, as indicated by a monotonic increase in the cell volume and systematic changes in properties. This limit may be due to the difficulty of stabilizing Ti2+ in this structure. For x=0.5 both the first order structural phase transition and the magnetic transition at 40 K are quenched. The samples obey the Curie-Weiss law to x=3 with nearly spin only effective moments along with θ values which range from −1090 K (x=0.5) to −1629 K (x=3). For x>3 a very large, ∼2×10−3 emu/mol, temperature independent (TIP) contribution dominates. Conductivity measurements on sintered, polycrystalline samples show semiconducting behavior for all compositions. Activation energies for Mott hopping derived from high temperature data range from ∼0.1 eV for x=0-1 and fall to a plateau of 0.06 eV for x=3-7. Low temperature data for x=3, 5 and 7 show evidence for Mott variable range hoping (VRH) with a T1/4 law and in one case between 5 and 17 K, a Efros-Shklovskii correlated hopping, T1/2 law, was seen, in sharp contrast to BaV10O15 where only the E-S law was observed up to 75 K. Seebeck coefficients are small (<35 μV/K), positive, roughly TIP and increase with increasing x up to x=5. This may point to a Heikes hopping of holes but a simple single carrier model is impossible. The compositions for x>3 are remarkable in that local moment behavior is lost, yet a metallic state is not reached. The failure of this system to be driven metallic even at such high doping levels is not fully understood but it seems clear that disorder induced carrier localization plays a major role. 相似文献
126.
127.
凝胶型聚合物电解质的电导率与温度的关系孙晓光,林云青,齐力,景遐斌,王佛松(中国科学院长春应用化学研究所长春130022)关键词凝胶电解质,离子电导率,活化能无定形聚合物电解质电导与温度的依赖关系一般可用Vogel-Tamman-Fulcherc(V... 相似文献
128.
研究了直流电场对含LiClO4的聚氧化乙烯(PEO)400与环氧树脂形成的液晶态互穿网络高分子忆禽子导体的电导率的影响。在室温至90℃范围内,电导率随外加电压增加面降低。外加电压越高,对电导率变化的影响越大。 相似文献
129.
The thermal conductivity of polyolefins and halogen-substituted polymers was studied in a broad temperature interval spanning both solid and melt states, in the range of pressures from 0.1 up to 100 MPa with the aid of a high-pressure-calorimeter in the continuous heating regime. Treatment of data on the pressure dependence of the thermal conductivity of melts in terms of Barker's equation yielded the values of quasilattice Grueneisen parameter B which exhibited the same dependence on molecular structure of a polymer as the parameter 3C/p from the Simha-Somcynsky equation of state (number of external degress of freedom per chain repeat unit). Analysis of the dependence of the thermal conductivity of polyethylene on the degree of crystallinity revealed the inadequacy of the current two-phase model which does not account for the microheterogeneity of the amorphous phase. It was concluded that interchain heat transfer makes the dominant contribution to the thermal conductivity of polymers both in amorphous and in crystalline states.
Zusammenfassung Mit Hilfe eines Hochdruck-- Kalorimeters mit kontinuierlicher Aufheizung wurde im Druckintervall 0,1 bis 100 MPa und in einem breiten Temperaturbereich, in den sowohl feste als auch flüssige Zustände gehören, die Wärmeleitfähigkeit von Polyolefinen und halogenierten Polymeren untersucht. Drückt man die Druckabhängigkeit der Wärmeleitfähigkeit der Schmelzen mit Hilfe der Barkerschen Gleichung aus, erhält man die Werte für den Quasigitter Grueneisen-Parameterb, der die gleiche Abhängigkeit von der Molekular-struktur eines Polymers zeigt, wie der Parameter 3C/p aus der Gleichung von Simha-Somcynsky (Zahl der externen Freiheitsgrade geteilt durch Kettenstruktureinheit). Eine Untersuchung der Abhängigkeit der Wärmeleitfähigkeit von Polyethylen von Kristallinitäts-grad zeigt die Mängel dieses Zwei-Phasen-Modelles, was die Mikroheterogenität der amorph-en Phase nicht erklärt. Man zog die Schlußfolgerung, daß ein Wärmetransport zwischen den Ketten sowohl im amorphen als auch im kristallinen Zustand den entscheidenden Beitrag zur Wärmeleitfähigkeit von Polymeren liefert.相似文献
130.
《Electroanalysis》2004,16(22):1837-1842
Electronic sensor technology remains of widespread and intense interest. There are compelling needs to detect chemical species ranging from small molecules dispersed in the gas phase to complex biopolymers in aqueous solution. This review describes some recent advances in three main areas: chemically sensitive resistors (chemiresistors, CRs) including inorganic and organic based devices, field effect transistors (FETs) with semiconducting layers and/or gates with chemical sensitivity, and sensors based on the differential conductivity of nanotubes and nanowires. Results reported in the last two to three years are emphasized, highlighting some current trends in the development of sensors for applications such as diagnostics, process monitoring, and security. 相似文献