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911.
Time‐resolved luminescence measurements of luminescent lanthanide complexes have advantages in biological assays and high‐throughput screening, owing to their high sensitivity. In spite of the recent advances in their energy‐transfer mechanism and molecular‐orbital‐based computational molecular design, it is still difficult to estimate the quantum yields of new luminescent lanthanide complexes. Herein, solid‐phase libraries of luminescent lanthanide complexes were prepared through amide‐condensation and Pd‐catalyzed coupling reactions and their luminescent properties were screened with a microplate reader. Good correlation was observed between the time‐resolved luminescence intensities of the solid‐phase libraries and those of the corresponding complexes that were synthesized by using liquid‐phase chemistry. This method enabled the rapid and efficient development of new sensitizers for SmIII, EuIII, and TbIII luminescence. Thus, solid‐phase combinatorial synthesis combined with on‐resin screening led to the discovery of a wide variety of luminescent sensitizers. 相似文献
912.
Ultrasensitive method to quantify intracellular zidovudine mono‐, di‐ and triphosphate concentrations in peripheral blood mononuclear cells by liquid chromatography–tandem mass spectrometry
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Ei Kinai Hiroyuki Gatanaga Yoshimi Kikuchi Shinichi Oka Shingo Kato 《Journal of mass spectrometry : JMS》2015,50(6):ii-ii
Although zidovudine (AZT) is not the preferred antiretroviral drug for adult HIV‐infected patients, it is still widely used in infants for both prevention of mother‐to‐infant HIV‐1 transmission and treatment of HIV‐infected children. However, it is difficult to measure intracellular concentrations of AZT metabolites in small blood samples due to their extremely low concentrations in peripheral blood mononuclear cells and interference by endogenous nucleotide triphosphates, residual plasma phosphates and electrolytes. We developed an ultrasensitive assay using liquid chromatography–tandem mass spectrometry (LC–MS/MS) for measurement of intracellular concentrations of zidovudine (AZT)‐monophosphate (AZT‐MP), ‐diphosphate (AZT‐DP) and ‐triphosphate (AZT‐TP). The high sensitivity was due to the improvement of peripheral blood mononuclear cells extraction for complete removal of plasma and electrolytes, alkalization of LC buffer and use of alkaline‐stable high performance liquid chromatography column and tetrabutylammonium hydroxide as the ion pair. Using this method, the lower limits of quantification of AZT, AZT‐MP, ‐DP and ‐TP were 6, 6, 10 and 10 fmol per sample, respectively. Accuracy ranged 89–115% and precision was lower than 15% in the quantification range of 6–6000 fmol/sample for plasma AZT and intracellular AZT‐MP and 10–10 000 fmol/sample for AZT‐DP and ‐TP. The validation parameters met the international requirements. Among nine AZT‐treated HIV‐infected adult patients, five had low AZT‐TP levels (<10 fmol/106 cells). Our assay has high sensitivity and is advantageous for evaluation of AZT phosphates in children and infants based on minimum blood sampling requirement. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
913.
Setsuko Todoriki Olivia Kimiko Kikuchi Motoko Nakaoka Mika Miike Toru Hayashi 《Radiation Physics and Chemistry》2002,63(3-6):349-351
“Soft-electron” is a new term we have created referring to electrons with energies of 300 kV or lower. Homogenous irradiation of surfaces with soft electrons can decontaminate dry food ingredients such as gains, pulses, spices, dehydrated vegetables and tealeaves without detrimental effects. Treatment of soybeans with electrons of acceleration voltages at 170 kV reduced their microbial count to an undetectable level. Pre-treatment of soybeans with soft electrons enabled the extension of soymilk without sterilization process at a high temperature (120°C). The gelatinized property of soymilk from soft electron-treated beans was better than that of high-temperature sterilized soymilks. These results indicate that soft-electron sterilization improved the quality of soybeans for the processing of soymilk and Tofu(soymilk curd). 相似文献
914.
BACKGROUND: Chromophore-assisted laser inactivation (CALI) is a powerful method for the study of in situ protein function in cellular processes. By using CALI, it is possible to abrogate the function of a target protein with unprecedented spatial and temporal resolution. However, CALI has some limitations, which restrict wider biological application, owing mainly to the use of antibody for target recognition. To circumvent the limitations, we have developed small molecule-based CALI (smCALI). RESULTS: The inositol 1,4,5-trisphosphate receptor (IP3R) was selected as the target protein and a malachite green-conjugated IP3 analog, MGIP3, was used as a small-molecular probe. We examined the effect of MGIP3-based CALI on Ca2+ release via IP3R using permeabilized smooth muscle cells. When the cells were treated with MGIP3 followed by laser irradiation, the IP3-induced Ca2+ release rate was decreased in a concentration- and irradiation time-dependent manner. The effect was specific for IP3R, because the Ca2+ uptake function of the co-localized sarco/endoplasmic reticulum Ca2+-ATPase was not affected. CONCLUSIONS: IP3R was specifically inactivated by smCALI using MGIP3. The efficiency of inactivation was calculated to be substantially greater than that of antibody-based CALI. The efficient and specific inactivation of IP3R would allow us to obtain an insight into spatiotemporal roles of IP3R in various cell functions. Our results may be considered to be a first step for a wider application of smCALI as a useful method to study spatiotemporal protein functions. 相似文献
915.
Daisuke Yuya Toshinori Kikuchi Tadashi Inoue Yoshitaka Iwai 《Journal of Macromolecular Science: Physics》2013,52(1):85-103
The nucleation rate was measured by directly counting the number of nuclei, which were developed while an isotactic polypropylene melt was flowing under shear in a thin film. The nucleation rate was enhanced with an increased rate of shear, e.g., by a factor of 10 larger at the rate of shear of 14 s?1 compared with the quiescent state, at 134°C. The ratio of the shear‐enhanced nucleation rate to the nucleation rate in the quiescent state was larger at a higher temperature of crystallization, i.e., about 10 times at 134°C to 590 times at 140°C. The increase of the nucleation rate under shear flow was explained by a reduction of the lateral and end (fold) surface free energies; the product σ s 2 σ e decreased to 3.2×10?7 for the sheared melt, from 6.0×10?7 (J m?2)3 for the isotropic state. The free energy reduction was caused by transition of the nucleus formation mode from three‐dimensional folded chain nuclei to two‐dimensional bundle nuclei, in which chains lie down on the glass substrate, aligning parallel to the flow direction. 相似文献
916.
Microstructural changes after several cycles of the thermomechanical treatment consisting of a small deformation by stress-induced martensitic transformation (fcc to hcp) and subsequent reversion to austenite by heating (referred to as 'training') have been studied by atomic force microscopy in Fe-Mn-Si based shape memory alloys. Well-trained samples contain a uniform distribution of thin martensite plates of the same variant, the widths of which decrease with increasing number of the training cycles, and their distribution becomes more uniform. Such microstructural development by training originates mainly from extremely thin plates (about 1 nm thick) of hcp phase that are still retained together with stacking faults in the austenite even after heating far above the reverse transformation temperature. In the reverse transformation on heating, a martensite plate that looks as though it is apparently one plate is, in fact, split into very thin plates, which indicates that the plate actually consists of extremely thin martensite plates and these thin plates are reverse-transformed one after another by reverse movement of the Shockley partial dislocations at their tips. This mode of reverse transformation ensures a perfect shape memory effect. 相似文献
917.
Hidetaka Yuge Takeshi Ken Miyamoto Tomofumi Kikuchi Yukihiro Iwasaki 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(12):m594-m596
In the first bis[ruthenium(II)–porphyrin]–dicarbene complex, μ‐[1,4‐phenylenebis(phenylmethylidene‐κC)]bis[(ethanol‐κO)(5,10,15,20‐tetra‐p‐tolylporphyrinato‐κ4N)ruthenium(II)] 1,2‐dichloroethane trisolvate, [Ru2(C20H14)(C48H36N4)2(C2H6O)2]·3C2H4Cl2, an inversion center is located at the center of the μ‐phenylene group, leading to a parallel arrangement for the pair of porphyrin ring systems. The bond lengths and angles compare favourably with literature values for ruthenium–porphyrin–monocarbene complexes; the Ru=C(carbene) bond length and the C(phenyl)—C(carbene)—C(phenylene) angle are 1.865 (3) Å and 112.3 (3)°, respectively. The RuII ion is displaced out of the C20N4 porphyrin least‐squares plane (by 0.2373 Å) toward the bridging ligand of the Ci‐symmetry dimer. The porphyrin ring systems of the dimer thus exhibit mildly domed conformations. 相似文献
918.
Haruhisa Konishi Kenta Takahashi Makoto Nakamura Hidefumi Sakamoto Keiichi Kimura 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(3-4):147-152
Complexation of π-coordinate calix[4]arene derivatives toward soft metal ions, silver and thallium (I) ions, has been studied by electrospray-ionization mass spectrometry. Competitive metal–ion complexation of three calix[4]arene derivatives demonstrates a significant effect of olefinic substituents and its location on the silver ion complexation, but there was no effect of them on the thallium ion complexation. The stability constants for the metal ion complexes of the calixarene derivatives in methanol have been successfully determined by a mass-spectrometric method using 18-crown-6 as the reference ligand. 相似文献
919.
We demonstrate an adjustable pure dispersion slope compensating-module based on strain-chirped fiber Bragg gratings.The center wavelength of the module is preserved while the pure dispersion slope is tuned. 相似文献
920.
S. Tsutsui J. Umemura H. Kobayashi T. Tazaki S. Nasu Y. Kobayashi Y. Yoda H. Onodera H. Sugawara T. D. Matsuda D. Kikuchi H. Sato C. Sekine I. Shirotani 《Hyperfine Interactions》2006,168(1-3):1073-1077
We have carried out Mössbauer spectroscopy and nuclear resonant inelastic scattering to elucidate the lattice dynamics in filled-Skutterudite compounds, especially phosphides. The second-order Doppler shift obeys the Debye model in RFe4P12. Nuclear quadrupole interaction reveals an unusual temperature dependence in these compounds. An anomaly is observed in 57Fe nuclear resonant inelastic scattering of these compounds. The energy where the anomaly observed in SmFe4P12 agrees with the phonon excitation energy observed by 149Sm nuclear resonant inelastic scattering. We have also performed the 99Ru Mössbauer measurements of SmRu4P12. 相似文献