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991.
Functional molecules such as dyes (Methyl Red, azobenzene, and Naphthyl Red) were tethered on D-threoninol as base surrogates (threoninol-nucleotide), which were consecutively incorporated at the center of natural oligodeoxyribonucleotides (ODNs). Hybridization of two ODNs involving threoninol-nucleotides allowed interstrand clustering of the dyes on D-threoninol and greatly stabilized the duplex. When two complementary ODNs, both of which had tethered Methyl Reds on consecutive D-threoninols, were hybridized, the melting temperature increased proportionally to the number of Methyl Reds, due to stacking interactions. Clustering of Methyl Reds induced both hypsochromicity and narrowing of the band, demonstrating that Methyl Reds were axially stacked relative to each other (H-aggregation). Since hybridization lowered the intensity of circular dichroism peaks at the pi-pi* transition region of Methyl Red (300-500 nm), clustered Methyl Reds were scarcely wound in the duplex. Alternate hetero dye clusters could also be prepared only by hybridization of two ODNs with different threoninol-nucleotides, such as Methyl Red-azobenzene and Methyl Red-Naphthyl Red combinations. A combination of Methyl Red and azobenzene induced bathochromic shift and broadening of the band at the Methyl Red region due to the disturbance of exciton interaction among Methyl Reds. But interestingly, the Methyl Red and Naphthyl Red combination induced merging of each absorption band to give a single sharp band, indicating that exciton interaction occurred among the different dyes. Thus, D-threoninol can be a versatile scaffold for introducing functional molecules into DNA for their ordered clustering. 相似文献
992.
Zheng HW Perez P Auchincloss P Blanis D Bodek A Budd H Eno S Fry CA Harada H Ho YH Kim YK Kumita T Mori T Olsen SL Shaw NM Sill A Thorndike EH Ueno K Imlay R Kirk P Lim J McNeil RR Metcalf W Myung SS Cheng CP Gu P Li J Li YK Ye MH Zhu YC Abashian A Gotow K Hu KP Low EH Mattson ME Piilonen L Sterner KL Lusin S Rosenfeld C Wang AT Wilson S Frautschi M Kagan H Kass R Trahern CG Breedon RE Kim GN Ko W Lander RL Maeshima K Malchow RL Smith JR Stuart D Abe K Fujii Y Higashi Y Kim SK Kurihara Y Maki A 《Physical review D: Particles and fields》1990,42(3):737-747
993.
994.
Y. Fujii H. Kakihana M. Okamoto T. Oi Y. Sakuma 《Isotopes in environmental and health studies》2013,49(7):203-208
Isotope separation by chromatographic electromigration has been studied for lithium (6Li and 7Li) and uranium (235U and 238U), using cation-exchange membranes as migration media. The membranes were pulled back against the direction of the movement of isotopic cations in a countercurrent manner. In both cases of the elements the lighter isotope, 6Li or 235U, was concentrated at the frontal part of a migration zone; at the extreme front the 6Li atom % increased to 16.8% from the original value of 7.5% after 386 cm migration, and the 235 U atom % rose to 0.743% from the original value of 0.723% after 200 cm migration. Isotope separation coefficients were experimentally determined: ε = (3.7 ± 0.4) μ 10?3 for lithium isotopes, and two slightly different values ε = (4.9 ± 1.0) μ 10?5 and (5.4 ± 1.1) μ 10?5 for uranium isotopes. The steep isotope accumulation was observed in a narrow boundary region. A mathematical expression for the isotope accumulation curve was derived, and the slope of the curve was assessed for each experimental result. 相似文献
995.
The magnetic field dependence of spontaneous oscillation in n-InSb is investigated. We have observed two types of variation in the oscillation with increasing magnetic field. One is an abrupt appearance of the oscillation between 0.56 T and 0.68 T. The other is the appearance of bifurcation in the oscillation period above 0.79 T. This can be explained by the change of the number of levels in the electron system, according to the generation-recombination model of Schöll for the self-generated chaos. The magnitude of the current at the onset of the oscillation decreases linearly with increasing magnetic field. 相似文献
996.
In the case of 38 and 96 kHz ultrasonic vibrating electrode (USVE) voltammetry of chlorpromazine, the oxidation current increased considerably with ultrasonic power (amplitude). Movement of the first oxidation product, crimson coloured cation radical, and the streaming of liquid in the neighbourhood of the USVE, were visually observed in order to understand the mechanism of the promotive effects of ultrasound on the oxidation reaction. The reaction profile of the oxidation of chlorpromazine in 38 kHz seems to be somewhat different from that in 96 kHz. However, the mechanical agitation of solution in the area nearest the electrode surface, which is essentially the same fundamental mechanism, takes place in both the cases of 38 and 96 kHz. Both micro- and macro-streamings due to the vibration of a small bubble on the electrode surface with a frequency lower than that of the ultrasonic wave were formed in 38 kHz. These streamings seemed to contribute to the agitation and the exchange of the solution near the electrode surface. However, at the same ultrasonic amplitude, the oxidation current at 96 kHz was much greater than that at 38 kHz. Such a promoting effect of ultrasound on the electrode reaction was considered to be due to the increase of the moving speed or to the acceleration of the particle in the solution. 相似文献
997.
Shinmoto H Oshio K Tanimoto A Higuchi N Okuda S Kuribayashi S Mulkern RV 《Magnetic resonance imaging》2009,27(3):355-359
Purpose
The purpose of this study was to investigate the need for biexponential signal decay modeling for prostate cancer diffusion signal decays with b-factor over an extended b-factor range.Materials and Methods
Ten healthy volunteers and 12 patients with a bulky prostate cancer underwent line scan diffusion-weighted MR imaging in which b-factors from 0 to 3000 s/mm2 in 16 steps were sampled. The acquired signal decay curves were fit with both monoexponential and biexponential signal decay functions and a statistical comparison between the two fits was performed.Results
The biexponential model provided a statistically better fit over the monoexponential model on the peripheral zone (PZ), transitional zone (TZ) and prostate cancer. The fast and slow apparent diffusion coefficients (ADCs) in the PZ, TZ and cancer were 2.9±0.2, 0.7±0.2×10−3 mm2/ms (PZ); 2.9±0.4, 0.7±0.2×10−3 mm2/ms (TZ); and 1.7±0.4, 0.3±0.1×10−3 mm2/ms (cancer), respectively. The apparent fractions of the fast diffusion component in the PZ, TZ and cancer were 70±10%, 60±10% and 50±10%, respectively. The fast and slow ADCs of cancer were significantly lower than those of TZ and PZ, and the apparent fraction of the fast diffusion component was significantly smaller in cancer than in PZ.Conclusions
Biexponential diffusion decay functions are required for prostate cancer diffusion signal decay curves when sampled over an extended b-factor range, providing additional, unique tissue characterization parameters for prostate cancer. 相似文献998.
The atomic structures and the formation processes of the Ga- and As-rich (2×2) reconstructions on GaAs(111)A have been studied. The Ga-rich (2×2) structure is formed by heating the As-rich (2×2) phase, but the reverse change hardly occurs by cooling the Ga-rich surface under the As2 flux. Only when the Ga-rich (2×2) surface covered with amorphous As layers was thermally annealed, the As-rich (2×2) surface is formed. The As-rich (2×2) surface consists of As trimers located at a fourfold atop site of the outermost Ga layer, in which the rest-site Ga atom is replaced by the As atom. 相似文献
999.
Mohamed H. Gabr Nguyen T. Phong Mohammad Ali Abdelkareem Kazuya Okubo Kiyoshi Uzawa Isao Kimpara Toru Fujii 《Cellulose (London, England)》2013,20(2):819-826
In this research, fully environment-friendly, sustainable and biodegradable ‘green’ composites were fabricated. A novel material comprised of microfibrillated cellulose and laponite clay with different inorganic/organic ratios (m/m) was prepared. The composites were characterized by tensile, bending and water absorption tests as well as dynamic mechanical analysis. The morphologies of these nanocomposites were evaluated through scanning electron microscopy. Results showed considerable improvement of mechanical properties; specifically in elastic modulus, tensile strength and flexural modulus with the addition of nanoclay up to 7.5 wt% nano-clay. The modulus of elasticity increased significantly by about 26 % at 5 wt% nanocaly. The flexural modulus increased by about 90 % at 7.5 wt% nanoclay. However, with an increased load of clay in the nanocomposite, the mechanical properties decreased due to the agglomeration of excessive nanoclay. The storage modulus was significantly increased at high temperature with increasing the load of nanoclay. 相似文献
1000.
Benzoic acid-doped titania electrodes were prepared from titanium alkoxide sols containing benzoic acid in order to examine the photocatalytic reaction of the fuel material concentrated on the titania surface of a photofuel cell electrode. This doping was developed in order to understand the physicochemical processes on the titania rather than to advance the practical use of the photofuel cells. The observed photocurrent and CO2 and H2O productions indicated that the oxidation of the benzoic acid enhanced the generation of electricity during the UV irradiation. Benzoic acid molecules should be oxidized by oxygen molecules and holes on the titania surface. The steam treatment of the electrodes improved the benzoic acid oxidation and the photocurrent because it promoted the titania densification and enhanced the interaction between the benzoic acid and titania. The benzoic acid-doped titania is a valid model of the fuel material concentrated in the porous titania when using benzoic acid as the fuel material. The contact between the benzoic acid and titania is important in order to obtain a high photofuel electric conversion. 相似文献