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121.
Veselov Mark S. Ivanenkov Yan A. Yamidanov Renat S. Osterman Ilya A. Sergiev Petr V. Aladinskiy Vladimir A. Aladinskaya Anastasia V. Terentiev Victor A. Ayginin Andrey A. Skvortsov Dmitry A. Komarova Katerina S. Chemeris Alexey V. Baimiev Alexey Kh. Sofronova Alina A. Machulkin Alexey E. Petrov Rostislav A. Maklakova Svetlana Yu. Bezrukov Dmitry S. Filkov Gleb I. Zainullina Liana F. Maximova Marina A. Zileeva Zulfiya R. Kartsev Victor G. Vakhitova Yulia V. Dontsova Olga A. 《Molecular diversity》2020,24(1):233-239
Molecular Diversity - A series of 5-oxo-4H-pyrrolo[3,2-b]pyridine derivatives was identified as novel class of highly potent antibacterial agents during an extensive large-scale high-throughput... 相似文献
122.
In this paper we show a lower bound for the on-line version of Heilbronn's triangle problem in d dimensions. Specifically,
we provide an incremental construction for positioning n points in the d-dimensional unit cube, for which every simplex defined
by d + 1 of these points has volume Ω(1/n(d+1)ln(d-2)-0.265 d+2.269) (for d ≥ 5). 相似文献
123.
124.
The kinetics of the reaction between the protonated species of trans-[Mo(CN)4O2]4– and salicylaldehyde (Hsal) was studied in the 7.8–12.0 pH range in H2O-MeOH mixtures. Spectroscopic characterization of the product indicates that the aqua and cyano ligands are substituted by sal– with formation of the [Mo(CN)3O (sal- 2O,O)]2– ion. The formation quotient, Kf for the overall reaction=31 (±1) at 25°C. In the presence ofan excess of ligand, the rate law is of the formd[Mo(CN)3O(sal- 2O,O)2–]/dt =kobs[Mo(CN)4O (H2O)2–]. The kobs value is equal to 2.9 (±8)×10–3 at 25°C. The activation parameters H (kobs) and S (kobs) are 103 (±9)kJmol–1 and 45 (±8)JK–1mol–1, respectively. The amount of the product formed decreases with increasing pH but the rate of the product formation increases. The reaction mechanism and the possible formation of Schiff base ligands in the presence of amines are discussed. 相似文献
125.
Ma?analytische Bestimmung von Lanthan mit Natriumwolframat in Anwesenheit von Adsorptionsindicatoren
Zusammenfassung Zur genauen und schnellen Bestimmung von Lanthan wird die Titration mit Natrium-wolframat unter Verwendung der Adsorptionsindicatoren Chlorphenolrot, o-Kresolrot und Methylrot, sowie der Gemische Methylrot + Bromkresolgrün und Chlorphenolrot + Anilinblau empfohlen. Der Fehler der Bestimmung beträgt höchstens 0,5%. Die Methode eignet sich zur Bestimmung von La3+ in reinen Salzen und zur Bestimmung der Summe von Seltenen Erdmetallen nach vorhergehender Abtrennung von anderen Schwermetallen, die mit Natriumwolframat einen schwerlöslichen Niederschlag bilden.
Volumetric determination of lanthanum using sodium tungstate in presence of adsorption indicators
The accurate and rapid method described employs the following indicators: chlorophenol red, o-cresol red, methyl red, and the mixtures methyl red + bromocresol green and chlorophenol red + aniline blue. In all instances the error is smaller than 0.5%. The method is suitable for La3+ determination in lanthanum salts and also for the determination of the total amount of rare earths after separation from other heavy metals forming with sodium tungstate difficultly soluble precipitates.相似文献
126.
JPC – Journal of Planar Chromatography – Modern TLC - Selected nicotinic acid derivatives have been chromatographed on RP-HPTLC plates with methanol-water in different volume... 相似文献
127.
Wieckowska A Bilewicz R Domagała S Woźniak K Korybut-Daszkiewicz B Tomkiewicz A Mroziński J 《Inorganic chemistry》2003,42(18):5513-5522
New face-to-face heterodinuclear complexes containing copper(II) and nickel(II) in identical tetraazamacrocyclic environments have been synthesized and characterized using ESI mass-spectrometry, X-ray diffraction, spectroscopic methods, and elemental analysis. These new bismacrocyclic systems were compared with the respective mono- and bismacrocyclic and [2]catenane homonuclear complexes. Interactions between the metal centers were monitored by magnetic and electrochemical measurements. Magnetic data indicate that all copper compounds studied behave as weakly interacting magnets. In the case of copper [2]catenane, the extent of magnetic interactions decreased when a benzocrown moiety was introduced between the macrocyclic units. On the basis of electrochemical data, the interactions between the metal centers were found to be substantially larger for the nickel complexes than for the corresponding copper ones. Interlocking of a benzocrown ether to form [2]catenane led to a nonequivalence of the metal centers and to the increase of donor abilities of the catenane compared to the respective bismacrocyclic complex. This is reflected by the shift of the first formal potential to less positive values. Intermetallic interactions for the heteronuclear nickel/copper complexes were found intermediary compared to the homonuclear ones. They were strengthened by shortening the spacer between the two tetraazamacrocyclic subunits which is a convenient way of fine-tuning the interactions. The increase of intermetallic interactions led to the increased stability of the intermediate mixed-valence states indicated by the higher values of comproportionation constants. 相似文献
128.
Alina Wojakowska E. Krzyżak Stanisława Plińska 《Journal of Thermal Analysis and Calorimetry》2007,88(2):525-530
Melting
and high temperature solid-state transitions in CoCl2
and CoBr2 are widely discussed. On the basis of DSC
and conductometric measurements it was found that melting process of CoCl2
is preceded by a solid-state transition appearing about 20 K below the melting
point of CoCl2. Due to deconvolution of the thermograms,
the enthalpy of fusion and that of solid-state transition were found to be
36.4 and 9.6 kJ mol–1, respectively. Melting
points of CoCl2 and CoBr2 were
established to be 999.0 and 949.7 K, respectively. Hitherto unknown enthalpy
of fusion of CoBr2 was determined to be 27.2 kJ mol–1.
A solid-state transition in CoBr2 at 650 K has been
confirmed. 相似文献
129.
Bartomiej Rogalewicz Alina Climova Ekaterina Pivovarova Jarosaw Sukiennik Kamila Czarnecka Pawe Szymaski Magorzata Szczesio Katarzyna Gas Maciej Sawicki Monika Pitucha Agnieszka Czylkowska 《Molecules (Basel, Switzerland)》2022,27(9)
A novel biologically active thiosemicarbazide derivative ligand L (N-[(phenylcarbamothioyl)amino]pyridine-3-carboxamide) and a series of its five metal(II) complexes, namely: [Co(L)Cl2], [Ni(L)Cl2(H2O)], [Cu(L)Cl2(H2O)], [Zn(L)Cl2] and [Cd(L)Cl2(H2O)] have been synthesized and thoroughly investigated. The physicochemical characterization of the newly obtained compounds has been performed using appropriate analytical techniques, such as 1H and l3C nuclear magnetic resonance (NMR), inductively coupled plasma (ICP), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR) and magnetic measurements. In order to study the pharmacokinetic profile of the compounds, ADMET analysis was performed. The in vitro studies revealed that the synthesized compounds exhibit potent biological activity against A549 human cancer cell line. 相似文献
130.
Summary (bpyH)3(H3O)[W(CN)8]·H2O reacts at high temperature to give the ionic species [W(bpy)(CN)6]2–. Tetraphenylphosphonium and tetraphenylarsonium salts were isolated as solids whereas the acid and its alkali metal salts were investigated in solution. The new complexes were characterized by u.v. and visible, i.r. and e.s.r. spectrometry, t.g. and d.t. analysis. The intensively coloured salts exhibit solvent—dependent absorption bands at low energy assigned to Wbpy transitions. 相似文献