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991.
Sangita Agarwal K. Veeran Gowda Amlan Kanti Sarkar Debotri Ghosh Uttam Bhaumik Tapas Kumar Chattaraj Tapan Kumar Pal 《Chromatographia》2008,67(11-12):893-903
A sensitive and selective liquid chromatographic tandem mass spectrometric (LC–MS–MS) method was developed for simultaneous identification and quantification of tamsulosin and dutasteride in human plasma, which was well applied to clinical study. The method was based on liquid–liquid extraction, followed by an LC procedure with a Gemini C-18, 50 mm × 2.0 mm (3 μm) column and using methanol:ammonium formate (97:3, v/v) as the mobile phase. Protonated ions formed by a turbo ionspray in positive mode were used to detect analytes and internal standard. MS–MS detection was by monitoring the fragmentation of 409.1 → 228.1 (m/z) for tamsulosin, 529.3 → 461.3 (m/z) for dutasteride and 373.2 → 305.3 (m/z) for finasteride (IS) on a triple quadrupole mass spectrometer. The lower limit of quantification for both tamsulosin and dutasteride was 1 ng mL?1. The proposed method enables the unambiguous identification and quantification of tamsulosin and dutasteride for clinical drug monitoring. 相似文献
992.
Superparamagnetic monodispersed spherical beta-MnO 2 nanoparticles of approximately 10 nm size with a band gap of 2.52 eV have been synthesized in toluene and support the oxidative phenol coupling reaction as a photocatalyst. 相似文献
993.
Gurubasavaraj PM Roesky HW Nekoueishahraki B Pal A Herbst-Irmer R 《Inorganic chemistry》2008,47(12):5324-5331
The reaction of LAlMeOH [L = CH(N(Ar)(CMe))2, Ar = 2,6-i-Pr2C6H3] with CpTiMe3, Cp*TiMe3, and Cp*ZrMe3 was investigated to yield LAlMe(mu-O)TiMe2Cp (2), LAlMe(mu-O)TiMe2Cp* (3), and LAlMe(mu-O)ZrMe2Cp* (4), respectively. The resulting compounds 2-4 are stable at elevated temperatures, in contrast to their precursors such as CpTiMe3 and Cp*ZrMe3, which already decompose below room temperature. Compounds 2-4 were characterized by single-crystal X-ray structural analysis. Compounds 2 and 3 were tested for ethylene polymerization in the presence of methylaluminoxane. The half-metallocene complex 3 has higher activity compared to 2. The polydispersities are in the range from 2.8 to 4.2. A copolymerization with styrene was not observed. 相似文献
994.
Ashis Kumar Satpati Manoj Kumbhakar Sukhendu Nath Haridas Pal 《Journal of photochemistry and photobiology. A, Chemistry》2008,200(2-3):270-276
Electron transfer (ET) rates between quinone acceptors and amine donors in micellar media show Marcus inversion behavior on correlating with the free energy changes of the ET reactions. The onset of Marcus inversion in these systems is seen to be tuned by about 0.25 eV by changing the type of the micelle. The results are rationalized on the basis of two-dimensional ET theory where ET occurs along intramolecular coordinate with non-equilibrium configuration along solvation coordinate. Maximum ET rates are seen to vary by about one order of magnitude in different micelles, and are attributed to the micelle-dependent changes in the separations of the interacting quinone–amine pairs. Tunings of Marcus inversion and ET rates by changing micellar microenvironments have been observed and suggested to have useful implications in different applied areas. 相似文献
995.
N. M. Karpyak R. G. Makitra G. A. Marshalok E. Ya. Pal’chikova 《Russian Journal of General Chemistry》2008,78(1):106-111
Solvent effect on the ratio of the endo and exo isomers formed by the Diels-Alder reaction of cyclopentadiene with acrylic acid esters can be described by multiparameter equations involving solvent polarity and electrophilic solvating power as determining parameters. The solvent polarity parameter Ω based on the stereoisomer ratio in the reaction with methyl acrylate cannot be regarded as a universal measure of solvating power, which was demonstrated using a number of examples. 相似文献
996.
Kapoor IP Srivastava P Singh G Singh UP Fröhlich R 《The journal of physical chemistry. A》2008,112(4):652-659
Three salts of phenylenediammonium diperchlorate have been prepared and characterized by X-ray crystallography. Their thermal decomposition has been studied by thermogravimetry (TG), differential thermal analysis (DTA), and explosion delay (DE) measurements. The kinetics of thermal decomposition was evaluated by model fitting and isoconversional methods using TG data. The oxidation-reduction reactions near the surface of thermolysing perchlorates may be responsible for the decomposition followed by explosion. The possible pathways of thermolysis have also been proposed. 相似文献
997.
Singh PK Nath S Kumbhakar M Bhasikuttan AC Pal H 《The journal of physical chemistry. A》2008,112(25):5598-5603
Often an intramolecular relaxation process takes place in a time scale similar to that of the solvent relaxation process. Under these circumstances the dynamic Stokes' shift of the probe can be modulated by the combined effect of these two relaxation processes. In the present article we have studied ultrafast solvent relaxation using three different coumarin dyes and proposed a methodology for the quantitative separation of the dynamics of two competing processes, namely, solvent relaxation and bond twisting, that take place simultaneously in the present systems. 相似文献
998.
Shaikh M Mohanty J Bhasikuttan AC Uzunova VD Nau WM Pal H 《Chemical communications (Cambridge, England)》2008,(31):3681-3683
The binding affinity of Neutral Red with cucurbit[7]uril (CB7) can be fine-tuned by addition and competitive binding of metal ions, which leads also to a pK(a) shift of the dye; this can be exploited to relocate the dye from the macrocyclic cavity of CB7 to the biomolecular pocket of bovine serum albumin. 相似文献
999.
The technique of Fock space multireference coupled-cluster (FSMRCC) is applied for the first time to the correlated calculation of the energy and width of a shape resonance in an electron-molecule collision. The procedure is based upon combining a complex absorbing potential with FSMRCC theory. Accurate resonance parameters are obtained by solving a small non-Hermitian eigenvalue problem. The potential-energy curve of the (2)Pi(g) state of N2- is calculated using the FSMRCC and multireference configuration-interaction (MRCI) level of theories. Comparison with the single-determinant Hartree-Fock theory indicates that correlation effects are important in determining the behavior of the resonance state. 相似文献
1000.
A. Mondal S. Chaudhuri A. K. Pal 《Applied Physics A: Materials Science & Processing》1987,43(1):81-84
Optical properties of p-type ZnTe films, deposited by hot-wall vacuum evaporation, were studied extensively in the range of incident photon energy 0.6–2.6 eV. Variations of refractive index, absorption and extinction coefficients with incident photon energy are reported in this communication. 相似文献