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41.
A liquid chromatographic chiral stationary phase based on (+)‐(18‐crown‐6)‐2,3,11,12‐tetracarboxylic acid was applied to the resolution of 15 analytes, including racemic rasagiline, a chiral drug for the treatment of Parkinson's disease, and its analogues. The composition of mobile phase was optimized to be ethanol/acetonitrile/acetic acid/triethylamine (80:20:0.2:0.3, v/v/v/v) by evaluating the chromatographic results for the resolution of five selected analytes under various mobile phase conditions. Under the optimized mobile phase conditions, racemic rasagiline was resolved quite well with a separation factor of 1.48 and resolution of 2.71 and its 14 analogues were also resolved reasonably well with separation factors of 1.06–1.54 and resolutions of 0.54–2.11. Among 15 analytes, racemic rasagiline was resolved best except for just one analyte. The analyte structure–enantioselectivity relationship indicated that racemic rasagiline has the most appropriate structural characteristics for resolution on the chiral stationary phase. 相似文献
42.
A series of self-healable polyurethane (SHPU)/modified graphene (MG) nanocomposites were synthesized from poly(tetramethylene glycol) (PTMG) and 4,4′-methylene diphenyl diisocyanate (MDI) with minute amounts (0–1 wt%) of MG which was chemically modified graphene oxide (GO) with phenyl isocyanate and reduced in the presence of phenylhydrazine. 相似文献
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Micro‐RNAs (miRNAs) are small, endogenous, singlestranded, and noncoding RNAs. The miRNAs have been found to perform important functions in many cellular processes, such as development, proliferation, differentiation, and apoptosis. Circulating miRNAs have been proposed as emerging biomarkers in diseases such as cancer, diabetes, and cardiovascular disease including acute myocardial infarction (AMI). In this study, we developed CE with LIF (CE‐LIF) using fluorescence‐labeled DNA probe for determination of low abundance miRNA in cell extracts. The target miRNA is miRNA‐499, a biomarker candidate of AMI with low abundance in biological samples. In order to measure the trace level of miRNA, we optimized the hybridization conditions such as hybridization time, temperature, and buffer solution. The highest fluorescence intensity of the hybridized miRNA‐499 was found when hybridization was conducted at 40°C in 50 mM Tris‐acetate (pH 8.0) buffer containing 50 mM NaCl, and 10 mM EDTA for 15 min. The hybridized miRNA‐499 was detected in cultured H9c2 cardiomyoblast cells and the analysis of miRNA‐499 was completed within 1 h using CE‐LIF. These results showed the potential of CE for fast, specific, and sensitive high‐throughput analysis of low‐abundance miRNAs in cell extracts, biofluids, and tissues. 相似文献
45.
Jinsoo Kim Jimin Park Young Ju Jung Eun Chol Kim Taek Ahn Jae-Won Ka 《Liquid crystals》2013,40(5):589-599
We have synthesised a series of new reactive mesogens with photopolymerisable di-acrylates and their corresponding non-reactive analogues based on the π-conjugated aromatic core, fluorene (F)-di-[thiophene (T)-benzene (B)], using the Stille and Suzuki coupling reaction. The effect of lateral alkyl chains on the 9-position of the central fluorene moiety as well as α, ω- side alkyl chains attached to the π-conjugated aromatic core on the mesomorphism was investigated by utilising differential scanning calorimetry (DSC) and polarising optical microscopy (POM). A wide angle X-ray scattering (WAXS) study at the various temperatures was also carried out to reveal phase structures. Photopolymerisable di-acrylates connected directly to the rigid aromatic core showed higher phase transition temperatures, probably due to the induced dipole moment in comparison with those of a non-reactive methyl–ether counterpart. 相似文献
46.
Hyun Ook Seo Dae Han Kim Kwang-Dae Kim Eun Ji Park Chae Won Sim Young Dok Kim 《Adsorption》2013,19(6):1181-1187
Adsorption and desorption of toluene on bare and TiO2-coated silica with a mean pore size of 15 nm under dry and humid conditions were studied using toluene breakthrough curves and temperature programmed desorption (TPD) of toluene and CO2. Two TiO2/silica samples (either partially or fully covered with TiO2) were prepared with 50 and 200 cycles of TiO2 atomic layer deposition (ALD), respectively. The capacity of silica to adsorb toluene improved significantly with TiO2-thin film coating under dry conditions. However, toluene desorption from the surface due to displacement by water was more pronounced for TiO2-coated samples than bare samples under humid conditions. In TPD experiments, silica with a thinner TiO2 film (50-ALD cycled) had the highest reactivity for toluene oxidation to CO2 both in the absence and presence of water. Toluene adsorption and oxidation reactivity of silica can be controlled by modifying the silica surface with small amount of TiO2 using ALD. 相似文献
47.
Prof. Pil Seok Chae Andrew C. Kruse Dr. Kamil Gotfryd Rohini R. Rana Kyung Ho Cho Prof. Søren G. F. Rasmussen Hyoung Eun Bae Richa Chandra Prof. Ulrik Gether Prof. Lan Guan Prof. Brian K. Kobilka Prof. Claus J. Loland Dr. Bernadette Byrne Prof. Samuel H. Gellman 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(46):15645-15651
Integral membrane proteins play central roles in controlling the flow of information and molecules across membranes. Our understanding of membrane protein structures and functions, however, is seriously limited, mainly due to difficulties in handling and analysing these proteins in aqueous solution. The use of a detergent or other amphipathic agents is required to overcome the intrinsic incompatibility between the large lipophilic surfaces displayed by the membrane proteins in their native forms and the polar solvent molecules. Here, we introduce new tripod amphiphiles displaying favourable behaviours toward several membrane protein systems, leading to an enhanced protein solubilisation and stabilisation compared to both conventional detergents and previously described tripod amphiphiles. 相似文献
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49.
Eun Joung Choi Eunha Kim Youngjun Lee Ala Jo Seung Bum Park 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(5):1370-1374
Fluorescence imaging enables the uniquely sensitive observation of functional‐ and molecular‐recognition events in living cells. However, only a limited range of biological processes have been subjected to imaging because of the lack of a design strategy and difficulties in the synthesis of biosensors. Herein, we report a facile synthesis of emission‐tunable and predictable Seoul‐Fluors, 9‐aryl‐1,2‐dihydrolopyrrolo[3,4‐b]indolizin‐3‐ones, with various R1 and R2 substituents by coinage‐metal‐catalyzed intramolecular 1,3‐dipolar cycloaddition and subsequent palladium‐mediated C H activation. We also showed that the quantum yields of Seoul‐Fluors are controlled by the electronic nature of the substituents, which influences the extent of photoinduced electron transfer. On the basis of this understanding, we demonstrated our design strategy by the development of a Seoul‐Fluor‐based chemosensor 20 for reactive oxygen species that was not accessible by a previous synthetic route. 相似文献
50.
Jung-Hoon Choi In-Hak Cho Hee-Chul Eun Hwan-Seo Park Yung-Zun Cho Ki-Rak Lee Geun-Il Park Song-Hyun Kim Chang-Ho Shin Jong-Kyung Kim 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(3):1731-1738
The pyrochemical process, which uses a dry method to recycle used nuclear fuel generates waste LiCl–KCl salt containing radioactive lanthanide elements. To reuse LiCl–KCl salt, the lanthanide elements are separated through a precipitation method promoted by oxygen sparging and the separated fission product of lanthanide oxide should be fabricated into durable wasteforms sustainable for several 1,000 years to store in a final geological repository. Herein, we report the fabrication of a borosilicate glass based wasteform with a glass matrix of SiO2–Al2O3–B2O3 having a high waste loading of 50 wt% lanthanide oxide. Th physical properties of four kinds of wasteforms having a different lanthanide oxide waste composition were evaluated. To investigate the long-term physical stability of each sample having 50 wt% lanthanide oxide waste loading, time–temperature–transformation (TTT) test was conducted at 500 and 700 °C for 60 and 180 h, and the physical properties were evaluated after each TTT test. 相似文献