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481.
[Cu(II)(3)Tb(III)(L(Pr))(NO(3))(2)(MeOH)(H(2)O)(2)](NO(3))·3H(2)O is a rare example of a 3d-4f single-molecule magnet prepared using a macrocyclic ligand: at low T, it exhibits frequency-dependent alternating-current susceptibility, indicative of slow relaxation of the magnetization. 相似文献
482.
Trioctylphosphine oxide capped cadmium selenide quantum dots, synthesized in organic media were rendered water soluble by
silica overcoating. Silanisation was done by a simple reverse microemulsion method using aminopropyl silane as the silica
precursor. Further, the strong photoluminescence of the silica-coated CdSe quantum dots has been utilized to visualize rabbit
adipose tissue-derived mesenchymal stem cells (RADMSCs) and Daltons lymphoma ascites (DLA) cancerous cells in vitro. Subsequently
the in vivo fluorescence behaviours of QDs in the tissues were also demonstrated by intravenous administration of the QDs
in Swiss albino mice. The fluorescence microscopic images in the stem cells, cancer cells and semi-thin sections of mice organs
proved the strong luminescence property of silica-coated quantum dots under biological systems. These results establish silica-coated
CdSe QDs as extremely useful tools for molecular imaging and cell tracking to study the cell division and metastasis of cancer
and other diseases. 相似文献
483.
484.
LIANG Fu-Tian GONG Datao HOU Suen LIU Chonghan LIU Tiankuan SU Da-ShunG TENG Ping-Kun XIANG Annie YE Jingbo JIN Ge 《中国物理C(英文版)》2013,(11):45-48
An all-transistor active-inductor shunt-peaking structure has been used in a prototype of 8 Gbps high- speed VCSEL driver which is designed for the optical link in ATLAS liquid Argon calorimeter upgrade. The VCSEL driver is fabricated in a commercial 0.25 p~m Silicon-on-Sapphire (SOS) CMOS process for radiation tolerant purpose. The all-transistor active-inductor shunt-peaking is used to overcome the bandwidth limitation from the CMOS pro- cess. The peaking structure has the same peaking effect as the passive one, but takes a small area, does not need linear resistors and can overcome the process variation by adjust the peaking strength via an external control. The design has been taped out, and the prototype has been proven by the preliminary electrical test results and bit error ratio test results. The driver achieves 8 Gbps data rate as simulated with the peaking. We present the all-transistor active-inductor shunt-peaking structure, simulation and test results in this paper. 相似文献
485.
Back Cover: Self‐Assembly of a Giant Tetrahedral 3 d–4 f Single‐Molecule Magnet within a Polyoxometalate System (Angew. Chem. Int. Ed. 51/2015) 下载免费PDF全文
486.
A facile one pot synthetic path for the preparation of pyrimidine-5-carbaldehydes from α-formylaroylketene dithioacetals is described. Amidines were allowed to react with α-formylaroylketene dithioacetals in DMF or acetonitrile to afford the pyrimidine-5-carbaldehydes. The starting compounds reported earlier were synthesized from α-oxoketene dithioacetals in excellent amount. 相似文献
487.
35 GHz electron paramagnetic resonance experiments on a powder sample of the magnetic molecule Mn 19 with a high-spin ground state S = 83/2 are presented. At low temperatures, the data are well described by the simulated spectra for an isolated spin with a zero-field-splitting parameter D = 0.004 cm (-1), which is, in particular, positive. Hence, Mn 19 is not a single-molecule magnet; the previously observed magnetic hysteresis at ultralow temperatures is likely due to intermolecular dipolar interactions. 相似文献
488.
The effect of blocking groups and stereochemistry of the substituents on the regio- and stereoselectivity in intramolecular nitrone-alkene cycloaddition (INAC) of hept-6-enoses are reported. L-ribo-Hept-6-enose 12 and D-lyxo-hept-6-enose 15, both containing a 2,3-O-isopropylidene blocking group, and L-xylo-hept-6-enose 23 and D-arabino-hept-6-enose 30, both with a 2,3-O-trans-diacetal blocking group, were prepared from D-ribose and D-arabinose, respectively. With N-alkyl hydroxylamine, lactols 12 and 15 underwent an INAC reaction to give cis-fused isoxazolidines exclusively whereas lactols 23 and 30 gave a mixture of cis-, trans-fused isoxazolidines (cyclohexanols) and bridged isoxazolidines (cycloheptanols). With the 2,3-O-trans-diacetal protecting group, the bridged bicyclo[4.2.1]isoxazolidines (cycloheptanols), via the endo mode of INAC cyclization, were synthesized for the first time from unbranched sugar derivatives 23 and 30. The stereochemical outcomes of these reactions were rationalized on the basis of transition state energies obtained by computation. The present INAC showed trivial temperature, but significant solvent dependence. For lactols 23 and 30, performing the INAC in 2-propanol gave the best yields of fused isoxazolidines (cyclohexanols) whereas in dichloromethane afforded the best yields of bridged isoxazolidines (cycloheptanols). 相似文献
489.
490.
Han H Yang L Xu Y Ding Y Bligh SW Zhang T Wang Z 《Rapid communications in mass spectrometry : RCM》2011,25(21):3339-3350
Geniposide, an iridoid glycoside, is an important and characteristic compound in the fruits of Gardenia jasminoides Ellis, a commonly used medicinal herb in Chinese traditional and folk medicine for the treatment of inflammation and jaundice. However, few studies have been carried out on the metabolism of geniposide. In this study, we have established a rapid and sensitive method using ultra‐performance liquid chromatography coupled with electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry (UPLC/ESI‐QTOF‐MS) for analysis of the metabolic profile of geniposide in rat urine after oral administration. A total of ten metabolites were detected and identified by comparing their fragmentation patterns with that of geniposide using Metabolynx? and MassFragment? software tools. The results revealed that the principal metabolism pathways of geniposide in rat occurred after deglycosylation of the irdoid glycoside take place and this is followed by glucuronidation and the pyran‐ring cleavages. The major metabolite, the glucuronic acid conjugate of genipin as observed in vivo, was further confirmed by the in vitro enzymatic study. The results of this work have demonstrated the feasibility of the UPLC/ESI‐QTOF‐MS approach for rapid and reliable characterization of metabolites from iridoid compounds. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献