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41.
2-(3,5-二氯-2-吡啶偶氮)-5-二甲氨基苯胺与铂(Ⅳ)显色反应的研究 总被引:8,自引:0,他引:8
研究了2-(3,5-二氯-2-吡啶偶氮)-5-二甲氨基苯胺(3,5-diCl-PADMA)与铂(Ⅳ)的显色反应及铂配合物的质子化行为。结果表明,在0.04~0.48mol/L的H2SO4溶液中,于加热的条件下,试剂可与铂(Ⅳ)形成稳定的1∶2绿蓝色PtL2H2+2配合物,其最大吸收波长位于634nm,表观摩尔吸光系数为9.73×104L·mol-1·cm-1,桑德尔灵敏度为0.002μg·cm-2。铂配合物的三级质子化常数分别为:lgKa1=3.91,lgKa2=-2.21,lgKa3=-3.37。较大量的常见金属离子及除钯、钌外的其它贵金属离子不干扰测定。利用Pt,Pd与试剂反应所需的温度差异,可以用差减法消除微量Pd的干扰.铂(Ⅳ)浓度在每10mL0~7.5μg范围内符合比尔定律。所拟方法用于二次合金管理样-88及催化剂中微量铂的测定,结果满意。 相似文献
42.
B. M. Bulychev V. N. Verbetskii A. I. Sizov T. M. Zvukova V. K. Genchel’ V. N. Fokin 《Russian Chemical Bulletin》2007,56(7):1305-1312
Crystallization of non-solvated aluminum hydride from a diethyl ether-benzene mixed solvent was studied. The desolvation of
AlH3·(Et2O)x etherate in solution and the crystallization of α-AlH3 during polythermal heating of the solution occur only in the presence of ≥10 wt.% LiAlH4. The process is multistage, and the crystallization begins with the formation of the AlH3·0.25Et2O solvate, which recrystallizes in the solid phase into γ-AlH3 and then α-AlH3. Four crystalline modifications of aluminum hydride were characterized by X-ray diffraction and electron microscopy.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1259–1265, July, 2007. 相似文献
43.
44.
45.
O. V. Gusev L. N. Morozova T. A. Peganova P. V. Petrovskii N. A. Ustynyuk 《Russian Chemical Bulletin》1994,43(3):474-477
A mixture ofendo-H andexo-H isomers (1a and1b) of the (4-C5Me5H)PtCl2 complex was prepared by the reaction of K2PtCl4 with C5Me5H in MeOH. The mixture of isomers reacts with CpTl in the presence of TiBF4 to give a novel complex, [(4-C5Me5H)Pt(5-C5H5)]+BF4
–, as a mixture ofendo-H- andexo-H-isomers (2a and2b). The data of1H and13C NMR spectroscopy of the resulting complexes are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 514–517, March, 1994. 相似文献
46.
Three highly sensitive spectrophotometric methods for the determination of platinum(IV) have been developed, based on its colour reactions with molybdate and basic dyes (BD) in aqueous solution in the presence of poly(vinyl alcohol). Platinum(IV) reacts with molybdate and BD to form ion — association complexes of composition (BD)2[Pt (MoO4)3]. The molar absorptivities are between 6.83 × 105 and 9.51 × 105 dm3mol–1cm–1, the highest value being found with nile blue. Suitable conditions for the reactions and the effects of foreign ions were investigated. The methods can be applied to the spectrophotometric determination of trace amounts of platinum(IV) in some catalysts and ores. 相似文献
47.
Danilov A. I. Molodkina E. B. Polukarov Yu. M. 《Russian Journal of Electrochemistry》2004,40(6):585-596
The oxidation of polycrystalline platinum in 0.5 M H2SO4 is studied by cyclic voltammetry at potential scan rates of 5–500 mV s–1 while varying the potential cycling range. The scheme, which is proposed for explaining the observed acceleration and deceleration of oxygen sorption at 0.75–1.0 V, accounts for the presence of oxygen in the subsurface layers of platinum (Oss) and the formation of a barrier layer comprising complexes Oss–Pt
n
–SO4. Cycling platinum secures certain steady-state contents of Oss at 0.01–1.35 V. In an anodic scan, Oss accumulates at E > 0.85 V (slow post-electrochemical stage) due to exchange of platinum and oxygen atom sites. In a cathodic scan, the desorption of most oxygen gives way to the adsorption of anions, which prevent residual Oss from appearing on the surface. The residual Oss disappears at E < 0.1 V after a sufficiently complete desorption of anions and the destruction of stable complexes Oss–Pt
n
–SO4. Varying the potential cyclic limit leads, after a delay, to other steady-state Oss contents. 相似文献
48.
B. Michalkiewicz 《Chemical Papers》2006,60(5):371-374
The reactions taking place during methane esterification in oleum were investigated. It was found that the primary products
were methyl bisulphate and formaldehyde, which was subsequently oxidized to carbon dioxide. The catalyst, Pd or PtCl4, was needed to activate methane and for its oxidation to the primary products. The formation of CO2 was not a catalytic process. It was found that the addition of either carbon dioxide or ester into the reaction mixture did
not slow down the reactions. Methane oxidation in oleum is an irreversible process, during which water is produced and subsequently
consumed to give sulphuric acid by the reaction with sulphur trioxide.
Presented at the 33rd International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 22–26 May
2006. 相似文献
49.
The hydrogenation of benzene and toluene was investigated over US-SSY, -Al2O3, and Ha1-MCM-41 supported platinum catalysts. The acidity of catalyst supports was measured by IR spectra of pyridine adsorption. On the Brönsted acid supported catalyst, both the hexacyclic saturation product and the pentacyclic one, the hydroisomerization product, were observed, and these two products were revealed to be primary reaction products. The two products were proposed to be formed competitively on Brönsted acid sites with carbonium ions as the reaction intermediate. By contrast, no hydroisomerization product was found on Lewis acid supported catalysts. It was inferred that the electron-deficient reaction intermediate formed on Lewis acids could not undertake any skeletal isomerization process to give a pentacyclic saturation product. 相似文献
50.
The paper presents the principles and advantages of a technique combining high performance liquid chromatography and hydride
generation atomic absorption spectrometry (HPLC-HGAAS) applied to speciation analysis of inorganic species of arsenic As(III)
and As(V) in ground water samples. With separation of the arsenic species on an ion-exchange column in the chromatographic
system and their detection by the hydride generation atomic absorption spectrometry, the separation of the analytical signals
of the arsenic species was excellent at the limits of determination of 1.5 ng/ml As(III) and 2.2 ng/ml As(V) and RSD of 4.3%
and 7.8% for the concentration of 25 ng/ml. The hyphenated technique has been applied for determination of arsenic in polluted
ground water in the course of the study on migration of micropollutants. For total arsenic concentration two independent methods:
HGICP-OES and HGAAS were used for comparison of results of real samples analysis. 相似文献