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91.
92.
Mandy Eibisch Sebastian Zellmer Rolf Gebhardt Rosmarie Süß Beate Fuchs Jürgen Schiller 《Rapid communications in mass spectrometry : RCM》2011,25(18):2619-2626
The liver is an important organ that is particularly involved in the lipid metabolism of the organism. Thus, high interest is nowadays focused on the lipid composition of the liver and particularly the liver parenchymal cells, the hepatocytes. Hepatocytes contain common phospholipids (PL) such as phosphatidylcholines, ‐ethanolamines and ‐inositols, for instance, that can be easily analyzed by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) even without previous separation of the PL mixture. However, in addition to common PL, hepatocytes possess also significant amounts of cardiolipin (CLP). The MS analysis of this PL is quite challenging because it (a) has a higher mass than common lipids and (b) possesses a higher negative charge. We will show here that caution is required if CLP is analyzed directly from the total lipid extract because PC dimers may be interpreted as cardiolipins if the positive ion MALDI mass spectra are analyzed. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
93.
Klaus Günther Alex von Bohlen Gerhard Paprott Reinhold Klockenkämper 《Fresenius' Journal of Analytical Chemistry》1992,342(4-5):444-448
Summary Total-reflection X-ray fluorescence (TXRF) and inductively coupled plasma mass spectrometry (ICP-MS) were used for the analysis of two biological reference materials. The quantifications were carried out after addition of one single standard element which serves as an internal standard in both cases. The results of TXRF analysis were good to satisfactory. The method is therefore suitable for fast multielement analysis, because it needs no special calibration specimens. The results of ICP-MS analysis are at least in the order of magnitude of the certified values. In some cases recoveries fit very well. For quantitative analysis, however, the use of the standard addition method or the calibration with external standards is required. 相似文献
94.
Shneor R Monaghan P Subedi R Anderson BD Aniol K Annand J Arrington J Benaoum H Benmokhtar F Bertin P Bertozzi W Boeglin W Chen JP Choi S Chudakov E Cisbani E Craver B de Jager CW Feuerbach RJ Frullani S Garibaldi F Gayou O Gilad S Gilman R Glamazdin O Gomez J Hansen JO Higinbotham DW Holmstrom T Ibrahim H Igarashi R Jans E Jiang X Jiang Y Kaufman L Kelleher A Kolarkar A Kuchina E Kumbartzki G LeRose JJ Lindgren R Liyanage N Margaziotis DJ Markowitz P Marrone S Mazouz M Meekins D Michaels R 《Physical review letters》2007,99(7):072501
We investigated simultaneously the 12C(e,e'p) and 12C(e,e'pp) reactions at Q2=2 (GeV/c)2, xB=1.2, and in an (e, e'p) missing-momentum range from 300 to 600 MeV/c. At these kinematics, with a missing momentum greater than the Fermi momentum of nucleons in a nucleus and far from the delta excitation, short-range nucleon-nucleon correlations are predicted to dominate the reaction. For (9.5+/-2)% of the 12C(e,e'p) events, a recoiling partner proton was observed back-to-back to the 12C(e,e'p) missing-momentum vector, an experimental signature of correlations. 相似文献
95.
Navasardyan T Adams GS Ahmidouch A Angelescu T Arrington J Asaturyan R Baker OK Benmouna N Bertoncini C Blok HP Boeglin WU Bosted PE Breuer H Christy ME Connell SH Cui Y Dalton MM Danagoulian S Day D Dodario T Dunne JA Dutta D El Khayari N Ent R Fenker HC Frolov VV Gan L Gaskell D Hafidi K Hinton W Holt RJ Horn T Huber GM Hungerford E Jiang X Jones M Joo K Kalantarians N Kelly JJ Keppel CE Kubarovski V Li Y Liang Y Malace S Markowitz P McGrath E McKee P Meekins DG Mkrtchyan H Moziak B 《Physical review letters》2007,98(2):022001
A large data set of charged-pion (pi+/-) electroproduction from both hydrogen and deuterium targets has been obtained spanning the low-energy residual-mass region. These data conclusively show the onset of the quark-hadron duality phenomenon, as predicted for high-energy hadron electroproduction. We construct several ratios from these data to exhibit the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark-->pion production mechanisms. 相似文献
96.
97.
The model studies were designed to obtain information concerning wind loads on a tall building by placing the model in a turbulent
shear flow simulating expected atmospheric boundary-layer winds. Since current design codes are inadequate for predicting
all possible motions of tall buildings, it is important that better knowledge of mean and fluctuating loadings and their distributions
becomes available.
Experiments were conducted to determine the mean and fluctuating forces and twisting moments at several levels over the surface
of a model. By determining the effects at several levels simultaneously, it was possible to correlate forces and moments at
five levels with one common level.
A single model was tested at varying orientations. Tests were also conducted with an identical model placed upstream so that
its wake influenced the flow around the instrumented model.
Results are presented in terms of distributions of force and moment coefficients and correlations at different levels. The
spectral character of the force and moment components is illustrated for one case.
Paper was presented at 1977 SESA Spring Meeting held in Dallas, TX on May 15–20. 相似文献
98.
99.
Two 2,6‐Dioxabicyclo[3.3.1]nonan‐3‐ones from Phragmanthera capitata (Spreng.) Balle (Loranthaceae)
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Bruno N. Lenta Joél T. Ateba Jean R. Chouna Makoah N. Aminake Flore Nardella Gabriele Pradel Beate Neumann Hans Georg Stammler Catherine Vonthron‐Sénécheau Silvère Ngouela Norbert Sewald 《Helvetica chimica acta》2015,98(7):945-952
Phytochemical investigation of the leaves of Phragmanthera capitata collected on Cassia spectabilis tree led to the isolation of two natural lactones, rel‐(1R,5S,7S)‐7‐[2‐(4‐hydroxyphenyl)ethyl]‐2,6‐dioxabicyclo[3.3.1]nonan‐3‐one ( 1 ) and 4‐{2‐[rel‐(1R,3R,5S)‐7‐oxo‐2,6‐dioxabicyclo[3.3.1]non‐3‐yl]ethyl}phenyl 3,4,5‐trihydroxybenzoate ( 2 ) together with the known compounds betulinic acid ( 3 ), dodoneine ( 4 ), quercetin 3‐O‐α‐L ‐rhamnopyranoside ( 5 ), quercetin 3‐O‐α‐L ‐arabinofuranoside ( 6 ), quercetin ( 7 ), betulin ( 8 ), lupeol ( 9 ), and sitosterol ( 10 ). Their structures were established by means of modern spectroscopic techniques, and the relative configuration of compound 1 was confirmed by X‐ray analysis. Compounds 1 and 2 were tested in vitro for their antiplasmodial activity against the Plasmodium falciparum chloroquine sensitive‐strains NF54 and 3D7. Compound 2 exhibited good antiplasmodial activity against both strains with IC50 of 2.4 and 4.9 μM , respectively, while compound 1 was inactive. 相似文献
100.
Susan Torabi Lukas Hammerschmidt Elena Voloshina Beate Paulus 《International journal of quantum chemistry》2014,114(14):943-951
The performance of wavefunction‐based correlation methods in theoretical solid‐state chemistry depends on reliable Hartree–Fock (HF) results for infinitly extended systems. Therefore, we optimized basis sets of valence‐triple‐ζ quality based on HF calculations for the periodic system of group‐12‐metal difluorides. Scalar‐relativistic effects were included in the case of the metal‐ions by applying small‐core pseudopotentials. To assess the quality of the proposed basis sets, the structural parameters, bulk moduli as well as cohesive and lattice energies of the systems were evaluated at the HF and the density functional theory levels. In addition to these two mean‐field approaches and to assess further employment of our basis sets to wavefunction‐based correlation methods we performed periodic local MP2 computations. Finally, the possibilities of pressure induced structural phase transitions occurring in the ZnF2, CdF2, and HgF2 were investigated. © 2014 Wiley Periodicals, Inc. 相似文献