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71.
Berthold A Laugere F Schellevis H de Boer CR Laros M Guijt RM Sarro PM Vellekoop MJ 《Electrophoresis》2002,23(20):3511-3519
Glass microdevices for capillary electrophoresis (CE) gained a lot of interest in the development of micrototal analysis systems (microTAS). The fabrication of a microTAS requires integration of sampling, chemical separation and detection systems into a microdevice. The integration of a detection system into a microchannel, however, is hampered by the lack of suitable microfabrication technology. Here, a microfabrication method for integration of insulated microelectrodes inside a leakage-free microchannel in glass is presented. A combination of newly developed technological approaches, such as low-temperature glass-to-glass anodic bonding, channel etching, fabrication of buried metal interconnects, and deposition of thin plasma-enhanced chemical vapour deposition (PECVD) silicon carbide layers, enables the fabrication of a CE microdevice with an integrated contactless conductivity detector. The fabrication method of this CE microdevice with integrated contactless conductivity detector is described in detail. Standard CE separations of three inorganic cations in concentrations down to 5 microM show the viability of the new microCE system. 相似文献
72.
73.
On the Thermal Stability of Binary Cadmium Phosphides A study on the thermal stability of the binary cadmium phosphides was carried out through three entirely different methods, i.e. the total pressure measurement, the partial pressure measurement of Cd and the estimation of the thermodynamic values by analogy considerations. The results showed the existance of a stable CdP2 phase at temperatures lower than 870 K and above this temperature Cd3P2 was found as the most stable condensed binary phase. 相似文献
74.
Sevenard DV Kolomeitsev AA Hoge B Lork E Röschenthaler GV 《Journal of the American Chemical Society》2003,125(41):12366-12367
Phenyl triflate reacts with CF3SiMe3/Q+F- (Q+ = [K(18-crown-6)]+, Me4N+) and (Me2N)3S+Me3SiF2- to afford the first noncyclic [10-S-5] sulfuranide dioxide salts, [(CF3)3SO2]-Q+, with three S-C bonds, whose molecular structure was determined by X-ray crystallography. 相似文献
75.
Berthold Hoge Christoph Thösen 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8-9):2151-2152
During our attempts to synthesize chiral bidentate bis(trifluoromethyl)phosphane containing ligands, we found a bis(trifluoromethyl)phosphanide induced formal insertion of acetone into tetrakis(trifluoromethyl)diphosphane. 相似文献
76.
We present a probabilistic analysis of integer linear programs (ILPs). More specifically, we study ILPs in a so-called smoothed
analysis in which it is assumed that first an adversary specifies the coefficients of an integer program and then (some of)
these coefficients are randomly perturbed, e.g., using a Gaussian or a uniform distribution with small standard deviation.
In this probabilistic model, we investigate structural properties of ILPs and apply them to the analysis of algorithms. For
example, we prove a lower bound on the slack of the optimal solution. As a result of our analysis, we are able to specify
the smoothed complexity of classes of ILPs in terms of their worst case complexity. This way, we obtain polynomial smoothed
complexity for packing and covering problems with any fixed number of constraints. Previous results of this kind were restricted
to the case of binary programs.
相似文献
77.
Robin F. Weitkamp Beate Neumann Hans‐Georg Stammler Berthold Hoge 《Angewandte Chemie (International ed. in English)》2019,58(41):14633-14638
The reaction of a strongly basic phosphazene (Schwesinger base) with water afforded the corresponding metastable hydroxide trihydrate [OH(OH2)3]? salt. This is the first hydroxide solvate that is not in contact with a cation and furthermore one of rare known water‐stabilized hydroxide anions. Thermolysis in vacuum results in the decomposition of the hydroxide salt and quantitative liberation of the free phosphazene base. This approach was used to synthesize the Schwesinger base from its hydrochloride salt after anion exchange in excellent yields of over 97 %. This deprotonation method can also be used for the phosphazene‐base‐catalyzed preparation of the Ruppert–Prakash reagent Me3SiCF3 using fluoroform (HCF3) as the trifluoromethyl building block and sodium hydroxide as the formal deprotonation agent. 相似文献
78.
Dr. Lewis R. Thomas-Hargreaves Chantsalmaa Berthold William Augustinov Dr. Matthias Müller Dr. Sergei I. Ivlev Dr. Magnus R. Buchner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(35):e202200851
Diphenylberyllium [Be3Ph6] is shown here to react cleanly as a Brønsted base with a vast variety of protic compounds. Through the addition of the simple molecules tBuOH, HNPh2 and HPPh2, as well as the more complex 1,3-bis-(2,6-diisopropylphenyl)imidazolinium chloride, one or two phenyl groups in diphenylberyllium were protonated. As a result, the long-postulated structures of [Be3(OtBu)6] and [Be(μ-NPh2)Ph]2 have finally been verified and shown to be static in solution. Additionally [Be(μ-PPh2)(HPPh2)Ph]2 was generated, which is only the second beryllium-phospanide to be prepared; the stark differences between its behaviour and that of the analogous amide were also examined. The first crystalline example of a beryllium Grignard reagent with a non-bulky aryl group has also been prepared; it is stabilised with an N-heterocyclic carbene. 相似文献
79.
Yulia Krupskaya Alexey Alfonsov Anupama Parameswaran Vladislav Kataev Dr. Rüdiger Klingeler Dr. Gunther Steinfeld Norman Beyer Mathias Gressenbuch Berthold Kersting Prof. Dr. Bernd Büchner Prof. Dr. 《Chemphyschem》2010,11(9):1961-1970
The ability of bridging thiophenolate groups (RS?) to transmit magnetic exchange interactions between paramagnetic NiII ions is examined. Specific attention is paid to complexes with large Ni? SR? Ni angles. For this purpose, dinuclear [Ni2L1(μ‐OAc)?I2][I5] ( 2 ) and trinuclear [Ni3L2(OAc)2][BPh4]2 ( 3 ), where H2L1 and H2L2 represent 24‐membered macrocyclic amino‐thiophenol ligands, are prepared and fully characterized by IR‐ and UV/Vis spectroscopy, X‐ray crystallography, static magnetization M measurements and high‐field electron spin resonance (HF‐ESR). The dinuclear complex 2 has a central N3Ni2(μ‐S)2(μ‐OAc)Ni2N3 core with a mean Ni? S? Ni angle of 92°. The macrocycle L2 supports a trinuclear complex 3 , with distorted octahedral N2O2S2 and N2O3S coordination environments for one central and two terminal NiII ions, respectively. The Ni? S? Ni angles are at 132.8° and 133.5°. We find that the variation of the bond angles has a very strong impact on the magnetic properties of the Ni complexes. In the case of the Ni2‐complex, temperature T and magnetic field B dependencies of M reveal a ferromagnetic coupling J=?29 cm?1 between two NiII ions (H=JS1S2). HF‐ESR measurements yield a negative axial magnetic anisotropy (D<0) which implies a bistable (easy axis) magnetic ground state. In contrast, for the Ni3‐complex we find an appreciable antiferromagnetic coupling J′=97 cm?1 between the NiII ions and a positive axial magnetic anisotropy (D>0) which implies an easy plane situation. 相似文献
80.
Asma Gul Aris Perperoglou Zardad Khan Osama Mahmoud Miftahuddin Miftahuddin Werner Adler Berthold Lausen 《Advances in Data Analysis and Classification》2018,12(4):827-840
Combining multiple classifiers, known as ensemble methods, can give substantial improvement in prediction performance of learning algorithms especially in the presence of non-informative features in the data sets. We propose an ensemble of subset of kNN classifiers, ESkNN, for classification task in two steps. Firstly, we choose classifiers based upon their individual performance using the out-of-sample accuracy. The selected classifiers are then combined sequentially starting from the best model and assessed for collective performance on a validation data set. We use bench mark data sets with their original and some added non-informative features for the evaluation of our method. The results are compared with usual kNN, bagged kNN, random kNN, multiple feature subset method, random forest and support vector machines. Our experimental comparisons on benchmark classification problems and simulated data sets reveal that the proposed ensemble gives better classification performance than the usual kNN and its ensembles, and performs comparable to random forest and support vector machines. 相似文献