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基于变色多酸P2Mo18 与绿光Tb3+之间的功能互补及分子间能量转移的原理, 在维生素C(VC)的还原下, P2Mo18 @Tb3+溶液由浅黄色变为蓝色, 发生荧光猝灭; 相反, 在H2O2氧化下, 溶液的蓝色褪去, 荧光得以恢复, P2Mo18 @Tb3+溶液呈现出可逆的化学响应变色及荧光开关性质. 利用紫外-可见(UV-Vis)及荧光(PL)光谱法对VC浓度进行定量检测, 分别以800 nm处的吸光度和 547 nm处荧光强度的对数值对VC浓度作图, 获得光谱法对VC检测的线性方程, 检出限分别为3.40×10-3和0.21 μmol/L; 利用UV-Vis及PL动力学方法对VC和H2O2检测的响应速度进行了考察, 响应时间分别为52和320 s; 通过UV-Vis光谱及动力学方法考察了VC检测的选择性及可重复使用性. 相似文献
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Limei Sun Kristine Spildo Ketil Djurhuus Arne Skauge 《Journal of Dispersion Science and Technology》2014,35(4):551-555
A laboratory selection of salinity for a low salinity water-low salinity surfactant (LS-LSS) process is presented in this paper with systematical investigation on surfactant phase behavior, interfacial tension (IFT), and dynamic retention in porous media with IOS2024 and isoamyl alcohol (IAA) as surfactant system. The results show that 0.4 wt% IOS2024 with 1 wt% IAA can provide ultra-low IFT of 10?3 mN/m at around 3000–4000 mg/L total dissolved solids, but at that salinity range the surfactant retention is very high. The search for an optimum surfactant formulation has to consider solution properties and retention in addition to the low IFT. The salinity for a LS-LSS process should thus not be focused on either optimal salinity or ultra-low IFT, but instead the best choice could be a compromise between the properties in question. The three-phase region, where ultra-low IFT are found, is also associated with high retention values. However, we show that as salinity is increased from a two-phase region with oil solubilized in a water continuous microemulsion, there is a region close to the three-phase boundary which has potential. This region does not give ultra-low, but fairly low (10?2 mN/m in this case) interfacial tensions, and also significantly lower retention. 相似文献
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Xuemei Liu Limei Cao Wei Sun Zhenhua Zhou Ji Yang 《Research on Chemical Intermediates》2016,42(7):6289-6300
A heterojunction thin film consisting of n-type titanium dioxide (TiO2) and p-type cuprous oxide (Cu2O) was fabricated on an FTO conducting glass. The TiO2 films were grown on the FTO glass by sol–gel and spray pyrolysis methods, and Cu2O was deposited on it via the hydrothermal method. The morphology, crystalline structure, and optical absorption characteristics were studied by scanning electron microscopy, X-ray diffraction, and ultraviolet–visible diffuse reflectance spectrum, respectively. The results show that the surface of the Cu2O/TiO2 film was composed of net and large grains, which contributed to a large specific surface area. The crystal phase of the TiO2 in the Cu2O/TiO2 film remained anatase. The crystal phase of the Cu2O could not be detected as it is found in traces. The Cu2O/TiO2 film had a stronger optical absorption ability than the pure TiO2 film. To investigate catalytic activity, a photocatalytic degradation experiment of the Cu2O/TiO2 film was performed in a homemade thin-layer micro-reactor. The photocatalytic degradation of methylene blue increased with increasing amounts of deposited Cu2O until a maximum limit was reached. The photocatalytic activity might have declined with an increase in Cu2O content. The metallic oxide has the potential to screen other photocatalysts from the UV source. 相似文献
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Hui Ye Limei Hui Katherine Kellersberger Lingjun Li 《Journal of the American Society for Mass Spectrometry》2013,24(1):134-147
Considerable effort has been devoted to characterizing the crustacean stomatogastric nervous system (STNS) with great emphasis on comprehensive analysis and mapping distribution of its diverse neuropeptide complement. Previously, immunohistochemistry (IHC) has been applied to this endeavor, yet with identification accuracy and throughput compromised. Therefore, molecular imaging methods are pursued to unequivocally determine the identity and location of the neuropeptides at a high spatial resolution. In this work, we developed a novel, multi-faceted mass spectrometric strategy combining profiling and imaging techniques to characterize and map neuropeptides from the blue crab Callinectes sapidus STNS at the network level. In total, 55 neuropeptides from 10 families were identified from the major ganglia in the C. sapidus STNS for the first time, including the stomatogastric ganglion (STG), the paired commissural ganglia (CoG), the esophageal ganglion (OG), and the connecting nerve stomatogastric nerve (stn) using matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI-TOF/TOF) and the MS/MS capability of this technique. In addition, the locations of multiple neuropeptides were documented at a spatial resolution of 25 μm in the STG and upstream nerve using MALDI-TOF/TOF and high-mass-resolution and high-mass-accuracy MALDI-Fourier transform ion cyclotron resonance (FT-ICR) instrument. Furthermore, distributions of neuropeptides in the whole C. sapidus STNS were examined by imaging mass spectrometry (IMS). Different isoforms from the same family were simultaneously and unambiguously mapped, facilitating the functional exploration of neuropeptides present in the crustacean STNS and exemplifying the revolutionary role of this novel platform in neuronal network studies. Figure
55 neuropeptides from 10 families were mapped in the crustacean stomatogastric nervous system with high spatial and spectral resolution via MALDI-TOF/TOF and MALDI-FT-ICR IMS 相似文献
16.
Shiliang He Hang Zhao Xiurong Guo Guang Xin Baozhan Huang Limei Ma Xinglong Zhou Rui Zhang Dan Du Xiaohua Wu Zhihua Xing Wen Huang Qianming Chen Yang He 《Tetrahedron》2013
J-AT nucleoside-based organogelators 1a and 1b were designed and synthesized. They were endowed with unparalleled superiority to natural nucleobase analogues 2–6 to gelate aromatic solvents due to their excellent self-assembly properties. The J-AT nucleoside-based organogelators showed a specific self-complementary base pair recognition characteristic. The gel stabilities of 1a and 1b were drastically influenced by adenine analogue 2, hardly affected by thymine analogue 3, uracil analogue 4, cytosine analogue 5, and mildly interrupted by guanine analogue 6. 相似文献
17.
Hongjuan Nian Qingchao Meng Wei Zhang Limei Chen 《Applied biochemistry and biotechnology》2013,169(1):170-180
The faldh gene coding for a putative Brevibacillus brevis formaldehyde dehydrogenase (FALDH) was isolated and then transformed into tobacco. A total of three lines of transgenic plants were generated, with each showing 2- to 3-fold higher specific formaldehyde dehydrogenase activities than wild-type tobacco, a result that demonstrates the functional activity of the enzyme in formaldehyde (HCHO) oxidation. Overexpression of faldh in tobacco confers a high tolerance to exogenous HCHO and an increased ability to take up HCHO. A 13C-nuclear magnetic resonance technique revealed that the transgenic plants were able to oxidize more aqueous HCHO to formate than the wild-type (WT) plants. When treated with gaseous HCHO, the transgenic tobacco exhibited an enhanced ability to transform more HCHO into formate, citrate acid, and malate but less glycine than the WT plants. These results indicate that the increased capacity of the transgenic tobacco to take up, tolerate, and metabolize higher concentrations of HCHO was due to the overexpression of B. brevis FALDH, revealing the essential function of this enzyme in HCHO detoxification. Our results provide a potential genetic engineering strategy for improving the phytoremediation of HCHO pollution. 相似文献
18.
H2-SCR is served as the promising technology for the controlling of NOx emission, and the Pd-based derivative catalyst exhibited high NOx reduction performance. Effectively regulating the electronic configuration of the active component is favorable to the rational optimization of noble Pd. In this work, a series of Pr1-xCexMn1-yPdyO3@Ni were successfully synthesized and exhibited superior NO conversion efficiency at low temperatures. 92.7 % conversion efficiency was achieved at 200 °C over Pr0.9Ce0.1Mn0.9Pd0.1O3@Ni in the presence of 4 % O2 with a GHSV of 32000 h−1. Meanwhile, the outstanding performance was obtained in the resistance to SO2 (200 ppm) and H2O (8 %). Deduced from the results of XRD, Raman, XPS, and H2-TPR, the modification of d orbit states in palladium was confirmed originating from the incorporation in the B site of Pr0.9Ce0.1Mn0.9Pd0.1O3. The existence of higher valence (Pd3+ and Pd4+) than the bivalence in Pr0.9Ce0.1Mn0.9Pd0.1O3 catalyst was evidenced by XPS analysis. Our research provides a new sight into the H2-SCR through the higher utilization of Pd. 相似文献
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