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201.
Troff RW Hovorka R Weilandt T Lützen A Cetina M Nieger M Lentz D Rissanen K Schalley CA 《Dalton transactions (Cambridge, England : 2003)》2012,41(27):8410-8420
A series of di-(m-pyridyl)-urea ligands were prepared and characterized with respect to their conformations by NOESY experiments and crystallography. Methyl substitution in different positions of the pyridine rings provides control over the position of the pyridine N atoms relative to the urea carbonyl group. The ligands were used to self-assemble metallo-supramolecular M(2)L(2) and M(3)L(3) macrocycles which are generated in a finely balanced equilibrium in DMSO and DMF according to DOSY NMR experiments and ESI FTICR mass spectrometry. Again, crystallography was used to characterize the assemblies. Methyl substitution in positions next to the pyridine nitrogen prevents coordination, while the other ligands form small metallo-supramolecular macrocycles. The incorporated urea carbonyl groups provide hydrogen bonding sites which converge towards the center of the assemblies. 相似文献
202.
Beyeh NK Weimann DP Kaufmann L Schalley CA Rissanen K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(18):5552-5557
The non-covalent interactions of different upper-rim-substituted C(2)-resorcinarenes with tetramethylammonium salts were analyzed in the gas phase in an Electrospray Ionization Fourier-transform ion-cyclotron-resonance (ESI-FTICR) mass spectrometer and by (1)H NMR titrations. The order of binding strengths of the hosts towards the tetramethylammonium cation in the gas phase reflects the electronic nature of the substituents on the upper rim of the resorcinarene. In solution, however, a different trend with particularly high binding constants for halogenated resorcinarenes has been observed. This trend can be explained by a synergetic effect originating from the interaction of the halogenated resorcinarenes with the counter anions through hydrogen bonding. This study highlights the importance of weak interactions in recognition processes and points out the benefits of comparing the gas-phase data with results obtained from solution experiments. 相似文献
203.
A. Kankainen Yu. N. Novikov M. Oinonen L. Batist V. -V. Elomaa T. Eronen J. Hakala A. Jokinen P. Karvonen M. Reponen J. Rissanen A. Saastamoinen G. Vorobjev C. Weber J. ?yst? 《The European Physical Journal A - Hadrons and Nuclei》2012,48(4):1-11
Low-energy-particle-induced fission is a cost-effective way to produce neutron-rich nuclei for spectroscopic studies. Fission has been utilized at the IGISOL to produce isotopes for decay and nuclear structure studies, collinear laser spectroscopy and precision mass measurements. The ion guide technique is also very suitable for the fission yield measurements, which can be performed very efficiently by using the Penning trap for fission fragment identification and counting. The proton- and neutron-induced fission yield measurements at the IGISOL are reviewed, and the independent isotopic yields of Zn, Ga, Rb, Sr, Cd and In in 25MeV deuterium-induced fission are presented for the first time. Moving to a new location next to the high intensity MCC30/15 light-ion cyclotron will allow also the use of the neutron-induced fission to produce the neutron rich nuclei at the IGISOL in the future. 相似文献
204.
Repo S Paldanius TA Hytönen VP Nyholm TK Halling KK Huuskonen J Pentikäinen OT Rissanen K Slotte JP Airenne TT Salminen TA Kulomaa MS Johnson MS 《Chemistry & biology》2006,13(10):1029-1039
The chicken genome encodes several biotin-binding proteins, including avidin and avidin-related protein 4 (AVR4). In addition to D-biotin, avidin binds an azo dye compound, 4-hydroxyazobenzene-2-carboxylic acid (HABA), but the HABA-binding properties of AVR4 are not yet known. Differential scanning calorimetry, UV/visible spectroscopy, and molecular modeling were used to analyze the binding of 15 azo molecules to avidin and AVR4. Significant differences are seen in azo compound preferences for the two proteins, emphasizing the importance of the loop between strands beta3 and beta4 for azo ligand recognition; information on these loops is provided by the high-resolution (1.5 A) X-ray structure for avidin reported here. These results may be valuable in designing improved tools for avidin-based life science and nanobiotechnology applications. 相似文献
205.
The synthesis and structural characterization of a new trimethylplatinum(IV) iodide complex of 4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine ligand L, {PtMe3IL} ( 1 ) is reported. The X-ray crystal structure shows that the terpyridine ligand L binds the platinum(IV) metal center in bidentate fashion, which is well supported by the 1H NMR spectrum of 1 . The complex 1 upon crystallization with 1,4-diiodotetrafluorobenzene (DITFB) forms the halogen bonded complex 1a ( 1· DITFB). The structural investigation shows that 1a exhibits the halogen bonding interaction in which the non-coordinated pyridyl nitrogen acts as halogen bond acceptors by forming I ··· N interaction with iodine atom of DITFB. In addition iodine atom of complex 1 also acts as weak halogen bond acceptor. 相似文献
206.
A. Jokinen C. Weber T. Eronen V. -V. Elomaa U. Hager J. Hakala S. Rahaman S. Rinta-Antila J. Rissanen J. Äystö 《Hyperfine Interactions》2006,173(1-3):143-151
JYFLTRAP is a Penning trap system at the accelerator laboratory in Jyväskylä, Finland that enables high-precision experiments with stored, exotic species that are produced at the IGISOL facility. On one hand, these can be performed within the trap itself, like e.g. mass spectrometry. On the other hand, the trap can be used to provide the highly purified species for further experiments, e.g. for trap-assisted nuclear decay spectroscopy. This contribution focuses on these two possible applications with the presentation of some recent results on superallowed beta decays. 相似文献
207.
Eve Saarikoski Sami Lipponen Marja Rissanen Jukka Seppälä 《Cellulose (London, England)》2012,19(3):661-669
Alkaline solutions of cellulose and polyethylene-co-acrylic acid (PE-co-AA) were mixed in order to prepare homogeneous cellulose/PE-co-AA blends. Different mixing methods were tested and the evolution of solutions was characterized by rheological methods and optical microscopy. In addition to the solution stage studies, the precipitated dry blends were characterized by Differential Scanning Calorimetry, Scanning Electron Microscopy, Fourier Transform Infrared and Dynamic Mechanical Analysis. Mixing the solutions led to the formation of a suspension, consisting of PE-co-AA particles dispersed evenly throughout the cellulose solution. Based on the conducted studies, it became clear that a uniform quality and the best mixing were attained with a method in which the suspension was frozen and melted between the mixing. In dry blends the polymers were found to be mixed on 1 μm scale, and the crystallization temperature of the PE-co-AA phase was increased ~6 °C due to the nucleation ability of the cellulose phase. 相似文献
208.
Jarmo Ropponen Tero Tuuttila Manu Lahtinen Sami Nummelin Kari Rissanen 《Journal of polymer science. Part A, Polymer chemistry》2004,42(22):5574-5586
The syntheses and thermal and X‐ray powder diffraction analyses of three sets of aliphatic polyester dendrimers based on 2,2‐bis(hydroxymethyl)propionic acid as a repeating unit and 2,2‐dimethyl‐1,3‐propanediol, 1,5‐pentanediol, and 1,1,1‐tris(hydroxymethyl)ethane as core molecules are reported. These dendritic polyesters were prepared in high yields with the divergent method. The thermal properties of these biodendrimers were evaluated with thermogravimetric analysis and differential scanning calorimetry. The thermal decomposition of the compounds occurred around 250 °C for the hydroxyl‐ended dendrimers and around 150 °C for the acetonide‐protected dendrimers. In addition, the crystallinity of the lower generation dendrimers was evaluated with X‐ray powder diffraction. The highest crystallinity and the highest melting points were observed for the first‐generation dendritic compounds. The higher generation dendrimers showed weaker melting transitions during the first heating scan. Only the glass‐transition temperatures were observed in subsequent heating scans. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5574–5586, 2004 相似文献
209.
210.
Gordana P. Radi?Verica V. Glo?ovi? Ivana D. Radojevi?Olgica D. Stefanovi? Ljiljana R. ?omi?Zoran R. Ratkovi? Arto ValkonenKari Rissanen Sre?ko R. Trifunovi? 《Polyhedron》2012,31(1):69-76
S-Alkyl (R = benzyl, methyl, ethyl, propyl and butyl) derivatives of thiosalicylic acid and the corresponding palladium(II) complexes were prepared and their structures were proposed on the basis of infrared, 1H and 13C NMR spectroscopy. The cis geometrical configurations of the isolated complexes were proposed on the basis of an X-ray structural study of the bis(S-benzyl-thiosalicylate)-palladium(II), [Pd(S-bz-thiosal)2] complex.Antimicrobial activity of the tested compounds was evaluated by determining the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) in relation to 26 species of microorganisms. The tested ligands, with a few exceptions, show low antimicrobial activity. The palladium(II) complexes, [Pd(S-R-thiosal)2], have statistically significant higher activity than the corresponding ligands. The complexes [Pd(S-et-thiosal)2] and [Pd(S-pro-thiosal)2] displayed the strongest activity amongst the all tested compounds. The palladium(II) complexes show selective and moderate antibacterial activity and significant antifungal activity. The most sensitive were Aspergillus fumigatus and Aspergillus flavus. 相似文献