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51.
Aslanoglu M Kutluay A Abbasoglu S Karabulut S 《Chemical & pharmaceutical bulletin》2008,56(3):282-286
A reliable and reproducible method for the determination of uric acid in urine samples has been developed. The method is based on the modification of a glassy carbon electrode by 3-acetylthiophene using cyclic voltammetry. The poly(3-acetylthiophene) modified glassy carbon electrode showed an excellent electrocatalytic effect towards the oxidation of uric acid in 0.1 m phosphate buffer solution (PBS) at pH 7.2. Compared with a bare glassy carbon electrode (GCE), an obvious shift of the oxidation peak potential in the cathodic direction and a marked enhancement of the anodic current response for uric acid were observed. The poly(3-acetylthiophene)/GCE was used for the determination of uric acid using square wave voltammetry. The peak current increased linearly with the concentration of uric acid in the range of 1.25 x 10(-5)-1.75 x 10(-4) M. The detection limit was 5.27 x 10(-7) M by square wave voltammetry. The poly(3-acetylthiophene)/GCE was also effective to determine uric acid and ascorbic acid in a mixture and resolved the overlapping anodic peaks of these two species into two well-defined voltammetric peaks in cyclic voltammetry at 0.030 V and 0.320 V (vs. Ag/AgCl) for ascorbic acid and uric acid, respectively. The modified electrode exhibited stable and sensitive current responses toward uric acid and ascorbic acid. The method has successfully been applied for determination of uric acid in urine samples. 相似文献
52.
O. Karabulut M. Parlak R. Turan U. Serincan E. Tasarkuyu B. G. Aknoglu 《Crystal Research and Technology》2003,38(9):811-916
N‐implantation to GaSe single crystals was carried out perpendicular to c‐axis with ion beam of 6 × 1015 ions/cm2 dose having energy values 30 keV and 60 keV. Temperature dependent electrical conductivities and Hall mobilities of implanted samples were measured along the layer in the temperature range of 100‐320 K. It was observed that N‐implantation decreases the resistivity values down to 103 Ω‐cm depending on the annealing temperature, from the room temperature resistivity values of as‐grown samples lying in the range 106‐107 Ω‐cm. The temperature dependent conductivities exhibits two regions (100‐190 and 200‐320 K) with the activation energies of 234‐267 meV and 26‐74 meV, for the annealing temperatures of 500 and 700 °C, respectively. The temperature dependence of Hall mobility for the sample annealed at 500 °C shows abrupt increase and decrease as the ambient temperature increases. The analysis of the mobility‐temperature dependence in the studied temperature range showed that impurity scattering and lattice scattering mechanisms are effective at different temperature regions with high temperature exponent. Annealing of the samples at 700 °C shifted impurity scattering mechanism toward higher temperature regions. In order to obtain the information about the defect produced by N‐implantation, the carrier density was analyzed by using single donor‐single acceptor model. We found acceptor ionization energy as Ea = 450 meV, and acceptor and donor concentration as 1.3 × 1013 and Nd = 3.5 × 1010 cm−3, respectively. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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We have performed ab initio self-consistent calculations based on full potential linear augmented plane-wave method (FP-LAPW) with the local density approximation (LDA) and generalised gradient approximation (GGA) to investigate the relativistic effects on the structural, electronic, transport and optical properties of II–VI compounds. We mainly show that the stabilisation (destabilisation) of s, p*(p) orbital energies reduces the lattice parameters of II–VI compounds, the band gaps and the effective masses. This, however, induces strong spin–orbit splitting of heavier II–VI compounds. 相似文献
56.
Bahri Sahin Huseyin Yilmaz Yasin Ust Ali Fuat Guneri Bahadır Gulsun 《European Journal of Operational Research》2009
One of the important parameters in the determination of optimal transportation system is economy. Therefore, a realistic method based on the technical, economical and operational parameters of various transportation modes, namely, road, railway, and sea routes is required in the analysis of costs. This method will take into consideration the probable price escalations during the lifetime of a certain transportation system. The cost of a unit of cargo or passenger per route length should be considered since it is an indicator of economics. In this paper, an approach for transportation cost analysis based on the economic analysis of the alternative modes of cargo or passenger transportation, is presented. 相似文献
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In this study, cathodoluminescence (CL) spectroscopy at direct current and alternating current under the sample temperature condition of 40–293 K using different modulation frequencies is presented for alkali feldspar from the Dartmoor granite (UK). These feldspars contain strain-controlled lamellar crypto- and microperthites that are cross-cut by strain-free deuteric microperthites. The CL spectra of the alkali feldspar at room and low temperature confirm that the observed emission peaked at ~460 nm could be associated with Al-O?-Al or Ti impurity centers, yellow emission ~560 nm could be associated with the presence of the centers such as radiation-induced defect centers, and ~756 nm emission could be associated with the Fe3+ impurity center on T1 and T2 sites. The consequence of their association is to produce different luminescence properties such as intensity, peak wavelength, and band shape. 相似文献
59.
Stefan B. Lindström Erdem Karabulut Artem Kulachenko Houssine Sehaqui Lars Wågberg 《Cellulose (London, England)》2012,19(3):809-819
The creep behavior of nanocellulose films and aerogels are studied in a dynamic moisture environment, which is crucial to
their performance in packaging applications. For these materials, the creep rate under cyclic humidity conditions exceeds
any constant humidity creep rate within the cycling range, a phenomenon known as mechanosorptive creep. By varying the sample
thickness and relative humidity ramp rate, it is shown that mechanosorptive creep is not significantly affected by the through-thickness
moisture gradient. It is also shown that cellulose nanofibril aerogels with high porosity display the same accelerated creep
as films. Microstructures larger than the fibril diameter thus appear to be of secondary importance to mechanosorptive creep
in nanocellulose materials, suggesting that the governing mechanism is found between molecular scales and the length-scales
of the fibril diameter. 相似文献
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