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991.
The percutaneous absorption of ketoprofen (KPF) from gel patches containing d-limonene and ethanol was investigated in rats. Plasma levels of KPF varied with the kind of polymers which constitute the gel patch, and the highest level was observed when the copolymer of ethylacrylate (EA) and diethyleneglycolmethacrylate (DEGMA) was used as a vehicle. The amount of KPF permeating through the rat skin from the gel patch was well correlated with that of ethanol. Permeations were enhanced with increase in the amount of d-limonene distributed from the vehicle to the skin tissue. The amount of d-limonene accumulated in the skin varied greatly with the kind of polymers; the highest accumulation was observed with the EA-DEGMA copolymer, and decreased with increasing affinity of d-limonene to the polymers. The reason EA-DEGMA copolymer showed the highest percutaneous absorption of KPF from gel patches containing d-limonene may be the hydrophilic nature of this polymer which showed the lowest affinity to d-limonene. 相似文献
992.
A. I. Nekhaev B. I. Kolobkov M. T. Toshev Kh. B. Dustov G. G. Aleksandrov 《Russian Chemical Bulletin》1991,40(4):827-830
Reaction of excess styrene with Fe3(CO)12 and sulfur (60°C, 15 h, Ar, S/Fe3(CO)12 0.6 g-atom/mole) gave Fe2(CO)6S2, Fe3(CO)9S2, Fe2(CO)6(S2CO), Fe2(CO)6S2(PhCHCH2), PhCHCH2S4, and a novel binuclear complex Fe2(CO)6(S2CH2S), whose structure was analyzed by x-ray crystallography. The crystals are monoclinic, a=7.764(3), b=13.205(4), c=6.628(6) Å, =98.97(3)°. V=671.2(7) Å3, Z=2, space group P21/m. The bond lengths are Fe-Fe 2.520(2), Fe-S 2.236(2), S-S 2.078(4), C-S 1.825(12), Fe-CO 1.784(8), and CO 1.148(9) Å.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 930–934, April, 1991. 相似文献
993.
It is possible to synthesize OGaF in an argon matrix by co-condensation of GaF with O atoms. The stretching vibrations of this compound are found at 943 and 690 cm−1 (16O69GaF). An exact calculation of the force field is possible with the aid of the observed 16O/18O and 69Ga/71Ga shifts. The following force constants are found: f(GaO) = 6.32; f(GaF) = 4.69; f(GaO/GaF) = −0.1 [102Nm−1] 相似文献
994.
Rusakov E. A. Tomchin A. B. Zelenin K. N. Drabkin A. E. Samoilenko N. P. 《Chemistry of Heterocyclic Compounds》1977,13(1):98-102
Thiosemicarbazides of 2-hydroxyphenylglyoxylic acid, which, depending on the conditions, undergo cyclization to interconvertible 5-(2-hydroxyphenyl)-6-oxo-1,2,4-triazine-3-thiones or (2-hydroxy-benzoyl)-2-1,2,4-triazoline-5-thiones, are formed by the action of thiosemicarbazide and its homologs on coumarindione. The thiosemicarbazones of 2-hydroxyphenylglyoxlyic and other 2-substituted phenylglyoxylic acids undergo cyclization to 6-(2-hydroxyphenyl)-5-oxo-1,2,4-triazine-3-thiones.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp, 116–121, January, 1977. 相似文献
995.
I. O. Konstantinov B. V. Zatolokin N. N. Krasnov Yu. G. Sevastyanov L. S. Volkova 《Journal of Radioanalytical and Nuclear Chemistry》1976,31(2):487-493
Procedures for determining traces of calcium, titanium, vanadium, chromium, iron, copper, niobium, molybdenum and tungsten
in tantalum are described utilizing 11 MeV proton activation. The instrumental method of analysis with the use of a Ge(Li)
detector and the radiochemical separation of the corresponding fractions are described. The formula for the calculation of
the concentration of traces with the use of thick target yields is given. Experimental data on the thick target yields of
radioisotopes44Sc,52Mn,56Co,65Zn,93mMo,96Tc are presented. Based on the experimental data, the detection limits are estimated at 1–10 ppb for the above mentioned metal
traces in tantalum. The successful solution of the task of the simultaneous determination of nine elements in tantalum confirms
the wide applicability of proton activation analysis. 相似文献
996.
The method proposed for the evaluation of statistical weights in paper I, and the three-state model [alpha-helical (alpha), extended (epsilon), and other (c) states] formulated in paper II, have been used to develop a procedure to predict the backbone conformations of proteins, based on the concept of the predominant role played by shortrange interactions in determining protein conformation. Conformational probability profiles, in which the probabilities of formation of three consecutive alpha-helical conformations (triad) and of four consecutive extended conformations (tetrad) have been defined relative to their average values over the whole molecule, are calculated for 19 proteins, of which 16 had been used in paper I to evaluate the set of statistical weights of the 20 naturally occurring amino acids. By comparing these conformational probability profiles to experimental x-ray observations, the following results have been obtained: 80% of the alpha-helical regions and 72% of the extended conformational regions have been predicted correctly for the 19 proteins. The percentage of residues predicted correctly is in the range of 53 to 90% for the alpha-helical conformation and in the range of 63 to 88% for the extended conformation for the 19 proteins in the two-state models [alpha-helical (alpha) and other (c) states, and extended (epsilon) and other (c) states]. In the three-state model, the percentage of residues predicted correctly is in the range of 47% to 77 for 19 proteins. These results suggest that the assumption of the dominance of short-range interactions, on which the predictive scheme is based, is a reasonable one. The present predictive method is compared with that of other authors. 相似文献
997.
Lifetimes of Hg(3P0) complexes were determined by simultaneous observation of Hg(3P0) optical absorption and complex emission, using a modulation technique and phase sensitive detection. The lifetimes of the mercury complexes with methanol, (1.4 ± 0.7) × 10-8 s, and water, ? 8 × 10-8 s, were found to be much shorter than reported in earlier work. For the ammonia complex, however a lifetime was measured which is in good agreement with previous determinations. Reasons for the large errors in earlier work where the methanol and water complex lifetimes were determined from complex emission data alone are discussed, and these data are reinterpreted. In the reaction rate of Hg(3P0) with methanol no detectable contribution from the termolecular process Hg(3P0) + 2CH3OH → (Hg·CH3OH)* + CH3OH could be observed. 相似文献
998.
I-Phenacylazolopyridazinium bromides reacted with 2,3-diphenylcyclopropenone or -thione in the presence of triethylaminc to give 3,4,6-triphenyl-2-pyrone or -2-thiopyrone and the corresponding azolopyridazine. Quaternized azolopyridazines reacted with hydrazine to give either 3,6-diphenylpyridazine and the corresponding azoloazine or hy ring opening of the azine part to give 1-methyl-2-(pyrazolyl-5′)imidazole. 相似文献
999.
Zusammenfassung Die Abhängigkeit der Struktur des o-Hydroxymandelsäurelactons von Lösungsmittel und Temperatur wird mit Hilfe IR- und NMR-spektroskopischer Methoden nachgewiesen.
The temperature and solvent dependence of the structures of 2-hydroxymandelic acid lactone and dioxindole have been shown by IR and NMR spectroscopy.相似文献
1000.
K. H. Beckmann 《Angewandte Chemie (International ed. in English)》1968,7(3):161-171
Measurement of the state of polarization of reflected light (ellipsometry) permits the determination of the thickness and refractive index of thin layers formed on a surface. The IR absorption spectra of such thin layers, which can be measured by means of internal reflection spectroscopy (IRS), provide information about their chemical composition. These methods have been used to study adsorption processes and the formation of reaction layers at semiconductor interfaces, and may also be used for measurements of free charge carriers in the space-charge region and in surface states. Results of such investigations are given in this article. 相似文献