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881.
882.
Jie Zhang Xinbiao Xiao Xiaozhen Sheng Chunyan Zhang Ruiqian Wang Xuesong Jin 《Applied Acoustics》2016
This paper presents a detailed Statistical Energy Analysis (SEA) and contribution analysis of the interior noise of a high-speed train through extensive simulations and measurements. The SEA model was developed based on the actual geometrical parameters of a benchmark high-speed coach. Sound transmission loss levels of the structural components of the car body, which are required in the SEA model, were tested in a dedicated acoustic laboratory following international standard ISO 140-3:1995. Modal densities of these structural components were derived from measured frequency response functions using the modal counting method. Damping loss factors were obtained using the half-power bandwidth method and the vibration attenuation method. By considering the relationship between sound radiation and power transmission, coupling loss factors between structures and cavities were estimated. Source inputs to the SEA model were derived from field experiment data. Interior noise due to those sources was predicted using the SEA model and the prediction was generally in good agreement with measurement. Contribution analysis was then performed using this validated model through parametric study, and this analysis was further examined experimentally. In conclusion, for the coach that was investigated in this paper, the key factors for interior noise are sidewall vibration, bogie area noise, and floor sound transmission loss. Based on this and other engineering considerations, an interior noise control strategy can be defined. 相似文献
883.
Hui-nan Leng 《应用数学学报(英文版)》2016,32(2):407-422
In this paper we consider infinite horizon backward doubly stochastic differential equations (BDSDEs for short) coupled with forward stochastic differential equations, whose terminal functions are non-degenerate. For such kind of BDSDEs, we study the existence and uniqueness of their solutions taking values in weighted L p (dx)?L 2(dx) space (p ≥ 2), and obtain the stationary property for the solutions. 相似文献
884.
Summary A simple, rapid and accurate, routine-HPLC method is described for simultaneous determination of acetaminophen, caffeine and
chlorpheniramine maleate in a new tablet formulation Chromatographic separation of the three pharmaceuticals was achieved
on a Hypersil CN column (150×5.0 mm, 5 μm) using a mobile phase comprising a mixture of acetonitrile, an ion-pair solution
and tetrahydrofuran (13:14:87, v/v,pH4.5). The flow-rate was changed from 1.0 mL min−1 (in 0≈7.5 min) to 1.8 mL min−1 (after 3.5 min). was complete in <10 min. The method was validated for system suitability, linearity, accuracy, precision,
limits of detection and quantitation, and robustness. Linearity, accuracy and precision were found to be acceptable over the
ranges 31.6≈315.8 μg mL−1 for acetaminophen, 9.5≈94.6 μg mL−1 for caffeine and 1.4≈13.8 μg mL−1 for chlorpheniramine maleate. 相似文献
885.
Huang X Li C Jiang S Wang X Zhang B Liu M 《Journal of colloid and interface science》2005,285(2):680-685
Complex monolayers of barbituric acid and melamine were formed by spreading a chloroform solution of amphiphilic barbituric acid on the subphase of melamine solution. It was confirmed that the complex monolayer was formed through in situ complementary hydrogen bonding at the air-water interface. It was interesting to find that the complex LB films showed supramolecular chirality although both of the molecules were achiral, as verified by the circular dichroism spectral measurements. It was suggested that the pi-pi stacking of the neighboring barbituric acid and melamine group in a helical sense resulted in the chirality of the molecular assemblies. Due to the directionality of the hydrogen bonding, the BA-M film could form regular aligned nanofibers on the AFM images. Increasing the subphase temperature will lead to the decrease of CD intensity and the change of the morphologies. We suggested that the strength of the hydrogen bonding resulted in the difference. 相似文献
886.
A study of the fluorescence of some newly synthesized europium complexes with pyrazolone derivatives 总被引:2,自引:0,他引:2
Qian DJ Leng WN Zhang Y Chen Z Van Houten J 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2000,56(14):457-2651
Some europium complexes with pyrazolone derivatives and 1,10-phenanthroline were synthesized and characterized. The europium ion was found to coordinate to O atoms of the pyrazolone derivatives and to N atoms of 1,10-phenanthroline. A strongly ligand-localized UV absorption leads to the europium-centered emissions between 580 and 750 nm which were assigned as the 5D0-->7F0,1,2,3,4 and 5D1-->7F3,4 transitions. A low site symmetry for the Eu3+ ion was confirmed from the observation of 5D0-->7F0 emission and from the splitting of the other bands. In contrast to many Eu complexes that have been investigated a rather weak emission was measured by introduction of a Schiff base to form a ternary complex with the pyrazolone derivative. The long fluorescence lifetimes of these complexes suggest an energy transfer process from ligands to Eu3+ ion through the triplet state of the ligands. 相似文献
887.
[reaction: see text] A library of hanging porphyrin xanthene (HPX) compounds containing pendant groups with various proton-donating abilities (pK(a) ranging from approximately 2 to 25) has been synthesized. Their corresponding chloroiron(III) complexes promote the catalase-like disproportionation of hydrogen peroxide. The overall activity and turnover numbers (TONs) are maximal for iron HPX complexes bearing acidic hydrogen-bond pendants. These results establish that careful control of intramolecular proton inventory can dramatically influence the catalytic activation of O-O bonds. 相似文献
888.
调节硫酸氧钒与盐酸羟胺溶液至pH~4制得的题目晶体属空间群P2_1/n,晶胞参数a=8.201,b=8.597,c=9.947A,β=93.00°,Z=4.结构解出精修后R因子为0.069.结果表明,不对称单位中二个羟胺根以侧接态与VO~(3+)配位,另一羟胺取端接态以O占据V的第五赤道配位位置,配位水处于氧钒基强键反位,Cl~-则在配阳离子界外以平衡电荷,晶体对的化学式确证为[(VO~(3+))(NH_2O~_)_2(NH_3O)(H_2O)][Cl~-] 相似文献
889.
In this paper, we study the regularity of generalized solutions u(x,t) for the n -dimensional quasi-linear parabolic diffraction problem. By using various estimates and Steklov average methods, we prove that (1): for almost all t the first derivatives ux(x,t) are Hölder continuous with respect to x up to the inner boundary, on which the coefficients of the equation are allowed to be discontinuous; and (2): the first derivative ut(x,t) is Hölder continuous with respect to (x,t) across the inner boundary. 相似文献
890.
To study the effect of ligand charge on DNA-ligand binding, we measured the difference in volume change of the noncovalent complex formed between calf thymus DNA and the charged and uncharged form of 3,8-diamino-6-phenylphenanthridine (DAPP). We found that the volume change for binding with the charged DAPPH+ is about 7.8 +/- 1.5 cm3 mol(-1) more positive than with the neutral DAPP. We hypothesize that this large difference in interaction volume originates from partial desolvation of the charge of DAPPH+ when it is bound to DNA. 相似文献