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71.
Nuss G Saischek G Harum BN Volpe M Belaj F Mösch-Zanetti NC 《Inorganic chemistry》2011,50(24):12632-12640
Reaction of potassium tris(mercapto-tert-butylpyridazinyl)borate K[Tn(tBu)] with copper(II) chloride in dichloromethane at room temperature led to the diamagnetic copper boratrane compound [Cu{B(Pn(tBu))(3)}Cl] (Pn = pyridazine-3-thionyl) (1) under activation of the B-H bond and formation of a Cu-B dative bond. In contrast to this, stirring of the same ligand with copper(I) chloride in tetrahydrofuran (THF) gave the dimeric compound [Cu{Tn(tBu)}](2) (2) where one copper atom is coordinated by two sulfur atoms and one hydrogen atom of one ligand and one sulfur of the other ligand. Hereby, no activation of the B-H bond occurred but a 3-center-2-electron B-H···Cu bond is formed. The reaction of copper(II) chloride with K[Tn(tBu)] in water gave the same product 2, but a formal reduction of the metal center from Cu(II) to Cu(I) occurred. When adding tricyclohexyl phosphine to the reaction mixture of K[Tn(R)] (R = tBu, Me) and copper(I) chloride in MeOH, the distorted tetrahedral Cu complexes [Cu{Tn(R)}(PCy(3))] (R = tBu 3, Me 4) were formed. Compound 4 is exhibiting an "inverted" κ(3)-H,S,S, coordination mode. The copper boratrane 1 was further investigated by density functional theory (DFT) calculations for a better understanding of the M→B interaction involving the d(8) electron configuration of Cu. 相似文献
72.
Haas W Rath T Pein A Rattenberger J Trimmel G Hofer F 《Chemical communications (Cambridge, England)》2011,47(7):2050-2052
Cu(2)ZnSnSe(4) nanoparticles have high potential to be used as ink for printable solar cells. Using transmission electron microscopy we show that these nanoparticles exhibit a broad range of chemical heterogeneity. These results are contrary to the interpretation of previous experimental work and will have considerable impact on the development of these nanoparticles. 相似文献
73.
Ma Z Rissner F Wang L Heimel G Li Q Shuai Z Zojer E 《Physical chemistry chemical physics : PCCP》2011,13(20):9747-9760
Density functional theory calculations are used to investigate the electronic structure of pyridine-based self-assembled monolayers (SAMs) on an Au(111) surface. We find that, when using pyridine docking groups, the bonding-induced charge rearrangements are frequently found to extend well onto the molecular backbone. This is in contrast to previous observations for the chemisorption of other SAMs, e.g., organic thiolates on gold, and can be explained by a pinning of the lowest unoccupied states of the SAM at the metal Fermi-level. The details of the pinning process, especially the parts of the molecules most affected by the charge rearrangements, strongly depend on the length of the molecular backbone and the tail-group substituent. We also mention methodological shortcomings of conventional density functional theory that can impact the quantitative details regarding the circumstances under which pinning occurs and highlight a number of peculiarities associated with bond dipoles that arise from Fermi-level pinning. 相似文献
74.
Martin Fink Guy Desaulniers Markus Frey Ferdinand Kiermaier Rainer Kolisch François Soumis 《European Journal of Operational Research》2019,272(2):699-711
Synchronization of workers and vehicles plays a major role in many industries such as logistics, healthcare or airport ground handling. In this paper, we focus on operational ground handling planning and model it as an archetype of vehicle routing problems with multiple synchronization constraints, coined as “abstract vehicle routing problem with worker and vehicle synchronization” (AVRPWVS). The AVRPWVS deals with routing workers to ground handling jobs such as unloading baggage or refuelling an aircraft, while meeting each job’s time window. Moreover, each job can be performed by a variable number of workers. As airports span vast distances and due to security regulations, workers use vehicles to travel between locations. Furthermore, each vehicle, moved by a driver, can carry several workers. We propose two mathematical multi-commodity flow formulations based on time-space networks to efficiently model five synchronization types including movement and load synchronization. Moreover, we develop a branch-and-price heuristic that employs both conventional variable branching and a novel variable fixing strategy. We demonstrate that the procedure achieves results close to the optimal solution in short time when compared to the two integer models. 相似文献
75.
Vid Agrež Ferdinand Bammer Boštjan Podobnik Rok Petkovšek 《Applied physics. B, Lasers and optics》2013,112(1):73-81
We present an experimental and numerical analysis, how deviations of the multiplexer-retardation influence the output power of a time-multiplexed dual channel laser. The laser has two different channels, each one with its own gain medium. The channels are time-multiplexed by a single crystal photo-elastic modulator. It enables to double the repetition rate and output power of the laser. However, as multiplexing is based on polarization-switching, the retardation of the modulator should be kept within certain limits. By experimental measurement and theoretical analysis, we determine the operational window within which the retardation should be kept to avoid additional losses into the resonator. The analysis was done for two configurations of the laser setup, namely with and without a quarter-wave plate. 相似文献
76.
On the basis of the realistic argon atom model consisting of 65 discrete effective levels numerical results for the collisional-radiative volume recombination, ionization and decay coefficients are obtained. The computations are carried out without any approximations of integral functions. The presented comparison of theoretical and experimental results for the decay coefficient shows that the values calculated by us are in much better agreement with experimental values than those obtained by Desai and Corcoran on the assumption that the argon atom is hydrogen-like. 相似文献
77.
Helmut Schwarz Claus Koppel Ferdinand Bohlmann 《Journal of mass spectrometry : JMS》1973,7(10):1211-1213
By the investigation of 13C-labelled dimethylbenzylbromide, it has been shown that the [M – Br]+ ion isomerises to a dimethyltrophylium cation. 相似文献
78.
Ferdinand Nf Ren Decorzant Walter Thommen Bruno Willhalm Günther Ohloff 《Helvetica chimica acta》1975,58(4):1016-1037
The four geometrical isomers of 1,3,5-undecatriene, 1a–d have been prepared (stereospecifically and non-stereospecifically), using either (1) the Wittig reaction, (2) thermal sigmatropic hydrogen shifts, (3) partial reduction of triple bonds by zinc, or (4) organocopper reagents. The thermal behaviour of the four 1,3,5-undecatrienes has been investigated and the products formed have been characterized. The spectra of 1a–d, and of related compounds, have been discussed in order to corroborate their configurational assignment. 相似文献
79.
Zusammenfassung Eine Methode wurde entwickelt, um Calcium und Magnesium in natürlichen Wässern bei pH 10 an einer Tl2O3-Anode unter Verwendung von ÄDTA und ÄGTA als Titrationsmittel zu bestimmen. Die dabei verwendete Apparatur eignet sich gut für Serienbestimmungen, da die Zugabe des Titrationsmittels und die Aufzeichnung des Kurvenverlaufs automatisch erfolgen. Die Auswertung wird graphisch durchgeführt.
Automatic amperometer determination of calcium and magnesium through complexometric titration
Summary A method has been developed for the determination of calcium and magnesium in natural waters at pH 10 on a Tl2O3-anode with employment of EDTA and EGTA as titration agents. The apparatus used is well suited to series determinations, because the addition of the titration agent and the recording of the course of the curve are done automatically. The evaluation is conducted graphically.相似文献
80.
Ferdinand Hucho 《Angewandte Chemie (International ed. in English)》1975,14(9):591-601
The three enzymes pyruvate dehydrogenase, dihydrolipoamide transacetylase, and dihydrolipoamide dehydrogenase constitute the pyruvate dehydrogenase multienzyme complex of E. coli; in mammals the complex also contains a kinase and a phosphatase. Multienzyme complexes are structural, functional, and regulatory units enabling the organism to operate more economically than with single enzymes. The pyruvate dehydrogenase multienzyme complex may stand at the switch-point between energy metabolism and gluconeogenesis. 相似文献