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891.
GF Wang XJ Song F Chen YZ Li XT Chen ZL Xue 《Dalton transactions (Cambridge, England : 2003)》2012,41(36):10919-10922
The reactions of FeCl(2) and CoCl(2) with a bistriazolium salt yields the NHC complexes [Fe(III)()(2)]I·H(2)O, [Fe(III)()(2)]PF(6)·CH(3)CN and [Co(III)()(2)]I·0.5CH(3)CN, through an unusual ring opening of one of the triazoyl rings, which leads to the formation of C,N,O tridentate ligands or . Furthermore, a Fe(ii) species [Fe(II)()(2)]·CH(2)Cl(2) was also obtained. 相似文献
892.
Liu Z Zhou H Lim YS Song JH Piao L Kim SH 《Langmuir : the ACS journal of surfaces and colloids》2012,28(25):9244-9249
Synthesis of silver nanoplates was studied in the modified polyol method, where the nucleation and seed stage occurred in a poly(ethylene glycol) (PEG)-water mixture solution, and the growth stage happened in the PEG environment. The morphological evolution of nanoplates was characterized using UV, SEM, and TEM. Interestingly, plane nanostructures with unusual jagged edges were finally formed in our modified polyol method. Using TEM, we observed the medium state of fusion between two nanoplates, resulting in generating unusual jagged edges. Therefore, a novel two-dimensional oriented attachment occurred in our modified polyol method, which involves smaller nanoplates as the building blocks. Further control experiments showed that the presence of water could break this kinetic preferred reactivity, leading to the formation of nanoparticles. 相似文献
893.
Choi I Song HD Lee S Yang YI Kang T Yi J 《Journal of the American Chemical Society》2012,134(29):12083-12090
We report core-satellites (Au-Ag) coupled plasmonic nanoassemblies based on bottom-up, high-density assembly of molecular-scale silver nanoparticles on a single gold nanoparticle surface, and demonstrate direct observation and quantification of enhanced plasmon coupling (i.e., intensity amplification and apparent spectra shift) in a single particle level. We also explore metal ion sensing capability based on our coupled plasmonic core-satellites, which enabled at least 1000 times better detection limit as compared to that of a single plasmonic nanoparticle. Our results demonstrate and suggest substantial promise for the development of coupled plasmonic nanostructures for ultrasensitive detection of various biological and chemical analytes. 相似文献
894.
GM Sun F Luo YM Song XZ Tian HX Huang Y Zhu ZJ Yuan XF Feng MB Luo SJ Liu WY Xu 《Dalton transactions (Cambridge, England : 2003)》2012,41(38):11559-11561
Herein, we report a new acylamide ligand and its application in the construction of a metal-organic framework. The resultant acylamide metal-organic framework, namely [Zn(2)(L)(OH)(btc)](n) (1, L = N(1),N(4)-bis(pyridin-3-ylmethyl) naphthalene-1,4-dicarboxamide, H(3)btc = benzene-1,3,5-tricarboxylic acid), was obtained by hydrothermal synthesis. The outstanding structural feature of it is the 0D + 2D → 2D polycatenation array containing a self-catenated feature which has never previously been observed. To the best of our knowledge, the coexistence of self-catenation and polycatenation phenomena is highly exceptional. 相似文献
895.
Y Wen L Xu C Li H Du L Chen B Su Z Zhang X Zhang Y Song 《Chemical communications (Cambridge, England)》2012,48(67):8410-8412
DNA assembles that can perform "OR" and "AND" logic gate operations were fabricated. The feasibility of intelligent logic controlled release was demonstrated through the controlled organization of gold nanoparticles on the surface of mesoporous silica by stimuli-induced structural transformation of DNA ensembles. 相似文献
896.
Wang B Inutan ED Trimpin S 《Journal of the American Society for Mass Spectrometry》2012,23(3):442-445
Liquid chromatography (LC) solvent assisted inlet ionization (SAII) mass spectrometry (MS) was previously reported to give
good chromatographic resolution and MS detection injecting 66 ng of a BSA tryptic digest. In analogy to nano-electrospray
ionization (nESI), we extend SAII LC/MS to nano-SAII (nSAII) operating at nL min–1 flow rates and demonstrate good quality ion chromatograms and mass spectra from injection of as little as 0.7 ng of BSA digest
onto a capillary LC column. Data dependent fragmentation is demonstrated for injection of 7 ng of a BSA digest. This method
has advantages over nESI in ease of use and low cost as it requires no voltage and is operational without the necessity of
connectors or fragile nESI emitters, although similar constricted tips can be helpful in nSAII to stabilize the signal at
low nanoliter flow. At a flow rate of 0.8 μL min–1, the only requirement for nSAII is that the exit-end of the capillary LC column be adjusted near the aperture of the heated
inlet of the mass spectrometer. 相似文献
897.
In this work, an electrochemical sensor 1-phenyl-3-methyl-4-(2-furoyl)-5-pyrazolone/multiwalled carbon nanotubes/glassy carbon
electrode (GCE) was prepared for the determination of xanthine (XN) in the presence of an excess of uric acid. Cyclic voltammetry
and differential pulse voltammetry were used to characterize the electrode. The oxidation of XN occurred in a well-defined
peak having E
p 0.73 V in phosphate buffer solution of pH 6.0. Compared with the bare GCE, the electrochemical sensor greatly enhanced the
oxidation signal of XN with negative shift in peak potential about 110 mV. Based on this, a sensitive, rapid, and convenient
electrochemical method for the determination of XN has been proposed. Under the optimized conditions, the oxidation peak current
of XN was found to be proportional to its concentration in the range of 0.3~50 μM with a detection limit of 0.08 μM. The analytical
utility of the proposed method was demonstrated by the direct assay of XN in urine samples and was found to be promising at
our preliminary experiments. 相似文献
898.
Dhruthiman R. Mantheni M. P. K. Maheswaram Hany F. Sobhi Naullage Indika Perera Alan T. Riga M. Ellen Matthews K. Alexander 《Journal of Thermal Analysis and Calorimetry》2012,108(1):227-233
Novel dielectric behavior of a linear increase in ionic conductivity prior to melt temperature was observed for active pharmaceutical
ingredients (APIs), organic chemicals, amino acids, and carbohydrates. Though, there are solids like polyolefins and long
chain organic compounds (tetracosane, pentacosane) which do not exhibit this premelt behavior (i.e., the temperature where
the onset of increase in ionic conductivity to melt temperature). We have discovered novel electrical conductivity properties
and other physical analytical variations which can lead to unique synthetic routes of certain chemical entities. The above-mentioned
unique variations are not related to solid–solid transitions which are quite often observed in pharmaceutical crystalline
solids. These new properties are related to amorphous crystalline behavior of a solid. We have also studied the effect of
various experimental variables: such as amount of mass tested, applied frequency at a given electric field and heating rate,
which results in varying the onset temperature of the increase in ionic conductivity. Melting of the solids was correlated
using differential scanning calorimetry (DSC). Activation energies for all the solids were measured in the premelt region
using an Arrhenius plot at a specific frequency since we observed changes in the conductivity with frequency. This study focused
on frequencies 0.1 to 10 Hz, since the conductivity at these frequencies related to surface analysis. This new physical properties
are leading to new electro synthetic procedures to modify or prepare chemicals. 相似文献
899.
Libby Yoerg M. Ellen Matthews Lakshmi Kaza Naullage Indika Perera David W. Ball John Moran Alan T. Riga 《Journal of Thermal Analysis and Calorimetry》2012,108(1):19-24
Three aldohexose monosaccharides, d-glucose, d-mannose, and d-galactose, were examined by scanning temperature dielectric analysis (DEA) from ambient temperatures through their melts.
Phase transitions, including glass transition (T
g) and melting temperature (T
m), were evaluated by differential scanning calorimetry (DSC). The monosaccharides were found to exhibit thermally-induced
dielectric loss spectra in their amorphous-solid phase before melting. Activation energies for electrical charging of each
of the monosaccharides were calculated from an Arrhenius plot of the tan delta (e″/e′, dielectric loss factor/relative permittivity) peak frequency versus reciprocal temperature in Kelvin. The DEA profiles
were also correlated with the DSC phase diagrams, showing the changes in electrical behavior associated with solid–solid and
solid–liquid transitions. 相似文献
900.
Hou-yin Zhao Yan Cao Song P. Sit Quentin Lineberry Wei-ping Pan 《Journal of Thermal Analysis and Calorimetry》2012,107(2):541-547
The pyrolysis behavior of bitumen was investigated using a thermogravimetric analyzer–mass spectrometer system (TG–MS) and
a differential scanning calorimeter (DSC) as well as a pyrolysis-gas chromatograph/mass spectrometer system (Py-GC/MS). TG
results showed that there were three stages of weight loss during pyrolysis—less than 110, 110–380, and 380–600 °C. Using
distributed activation energy model, the average activation energy of the thermal decomposition of bitumen was calculated
at 79 kJ mol−1. The evolved gas from the pyrolysis showed that organic species, such as alkane and alkene fragments had a peak maximum temperature
of 130 and 480 °C, respectively. Benzene, toluene, and styrene released at 100 and 420 °C. Most of the inorganic compounds,
such as H2, H2S, COS, and SO2, released at about 380 °C while the CO2 had the maximum temperature peaks at 400 and 540 °C, respectively. FTIR spectra were taken of the residues of the different
stages, and the results showed that the C–H bond intensity decreased dramatically at 380 °C. Py-GC/MS confirmed the composition
of the evolved gas. The DSC revealed the endothermic nature of the bitumen pyrolysis. 相似文献