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111.
Caterina Trotta Dr. Gabriel Menendez Rodriguez Dr. Leonardo Tensi Dr. Alexander V. Yakimov Dr. Luca Rocchigiani Prof. Anna Donnadio Prof. Cristiano Zuccaccia Prof. Christophe Copéret Prof. Alceo Macchioni 《欧洲无机化学杂志》2023,26(26):e202300211
A stringent comparison between two pairs of molecular/immobilized water oxidation catalysts ([Cp*Ir(Me-pica)Cl], 1 , versus 1_SiO2 , Me-pica=κ2-N-methyl-picolinamide; [Cp*Ir(pysa)NO3], 2 , versus 2_SiO2 , pysa=κ2-pyridine-2-sulfonamide]) reveals distinctive catalytic trends. While the molecular compound 1 exhibits a substantial higher activity than the analogous immobilized system 1_SiO2 , under all the experimental conditions explored, the contrary is found with 2 that is far less active than its immobilized counterpart 2_SiO2 . This is explained by the unique tendency of 2 to form dimeric complexes [Cp*Ir-(κ2-μ2-Hpysa)(κ2-μ2-pysa)IrCp*], 2 a , in phosphate buffered solution at pH 7, and [Cp*Ir-(κ2-μ2-Hpysa)2IrCp*], 2 b , in water. 2 a and 2 b have been completely characterized in solution by multinuclear and multidimensional NMR spectroscopy. They have been also isolated as single crystals and their structure in solid state determined by X-Ray diffractometry. 2 a and 2 b appear to be off-cycle species, whose formation is detrimental for water oxidation activity, as indicated by the observation of a long induction period when 2 a is used as catalytic precursor. In addition, TOF versus ΔE (E−E0=−RT/nF ln([IO4−]/[IO3−]) trends for the first two runs do not overlap for catalyst 2 and TOFmax is remarkably higher in the second run upon the addition of fresh NaIO4. In the immobilized system 2_SiO2 the detrimental associative processes are likely inhibited leading to an activity higher than that of 2 . 相似文献
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Baudat Emilie Gautier Céline Fichet Pascal Destrel Eric Colin Christèle Giuliani Margaux Lambrot Gabriel 《Journal of Radioanalytical and Nuclear Chemistry》2021,328(2):637-650
Journal of Radioanalytical and Nuclear Chemistry - 90Sr radiochemical method using nitric acid for Sr and Ca separation was optimized using design of experiments methodology. Nitric acid... 相似文献
114.
Gabriel Hancu Daniela Lupu Andreea Milan Monica Budu Enik Barabs‐Hajdu 《Biomedical chromatography : BMC》2021,35(1)
Venlafaxine (VFX) is a serotonin and norepinephrine reuptake inhibitor chiral drug used in therapy as an antidepressant in the form of a racemate consisting of R‐ and S‐VFX. The two enantiomers of VFX exhibit different pharmacological activities: R‐VFX inhibits both norepinephrine and serotonin synaptic reuptake, whereas S‐VFX inhibits only the serotonin one. R‐ and S‐VFX are metabolized in the liver to the respective R‐ and S‐O‐desmethylvenlafaxine (ODVFX), R‐ and S‐N‐desmethylvenlafaxine (NDVFX), and R‐ and S‐N,O‐didesmethylvenlafaxine (NODVFX). The pharmacological profile of ODVFX is close to that of VFX, whereas the other two chiral metabolites (NDVFX and NODVFX) have lower affinity for the receptor sites. The pharmacokinetics of the VFX enantiomers appear stereoselective, including the metabolism process. In the past 20 years, several studies describing the enantioselective analysis of R‐ and S‐VFX in pharmaceutical formulations and its chiral metabolites in biological matrices were published. These methods encompass liquid chromatography coupled with UV detection, mass spectrometry, or tandem mass spectrometry, and capillary electrophoresis. This paper reviews the published methods used for the determination of the individual enantiomers of VFX and its chiral metabolites in different matrices. 相似文献
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2‐Phenylethanol, racemic 1‐phenyl‐2‐propanol, and 2‐methyl‐1‐phenyl‐2‐propanol have been pyrolyzed in a static system over the temperature range 449.3–490.6°C and pressure range 65–198 torr. The decomposition reactions of these alcohols in seasoned vessels are homogeneous, unimolecular, and follow a first‐order rate law. The Arrhenius equations for the overall decomposition and partial rates of products formation were found as follows: for 2‐phenylethanol, overall rate log k1(s−1)=12.43−228.1 kJ mol−1 (2.303 RT)−1, toluene formation log k1(s−1)=12.97−249.2 kJ mol−1 (2.303 RT)−1, styrene formation log k1(s−1)=12.40−229.2 kJ mol−1(2.303 RT)−1, ethylbenzene formation log k1(s−1)=12.96−253.2 kJ mol−1(2.303 RT)−1; for 1‐phenyl‐2‐propanol, overall rate log k1(s−1)=13.03−233.5 kJ mol−1(2.303 RT)−1, toluene formation log k1(s−1)=13.04−240.1 kJ mol−1(2.303 RT)−1, unsaturated hydrocarbons+indene formation log k1(s−1)=12.19−224.3 kJ mol−1(2.303 RT)−1; for 2‐methyl‐1‐phenyl‐2‐propanol, overall rate log k1(s−1)=12.68−222.1 kJ mol−1(2.303 RT)−1, toluene formation log k1(s−1)=12.65−222.9 kJ mol−1(2.303 RT)−1, phenylpropenes formation log k1(s−1)=12.27−226.2 kJ mol−1(2.303 RT)−1. The overall decomposition rates of the 2‐hydroxyalkylbenzenes show a small but significant increase from primary to tertiary alcohol reactant. Two competitive eliminations are shown by each of the substrates: the dehydration process tends to decrease in relative importance from the primary to the tertiary alcohol substrate, while toluene formation increases. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 401–407, 1999 相似文献
117.
Leulescu Marian Rotaru Andrei Pălărie Ion Moanţă Anca Cioateră Nicoleta Popescu Mariana Morîntale Emilian Bubulică Maria Viorica Florian Gabriel Hărăbor Ana Rotaru Petre 《Journal of Thermal Analysis and Calorimetry》2018,134(1):209-231
Journal of Thermal Analysis and Calorimetry - The food-colouring dye tartrazine is a significant additive and in the same time a biologically active material. Thermal behaviour of trisodium... 相似文献
118.
Interrupted Baeyer–Villiger Rearrangement: Building A Stereoelectronic Trap for the Criegee Intermediate 下载免费PDF全文
Dr. Vera A. Vil' Gabriel dos Passos Gomes Oleg V. Bityukov Prof. Konstantin A. Lyssenko Prof. Gennady I. Nikishin Prof. Igor V. Alabugin Prof. Alexander O. Terent'ev 《Angewandte Chemie (International ed. in English)》2018,57(13):3372-3376
The instability of hydroxy peroxyesters, the elusive Criegee intermediates of the Baeyer–Villiger rearrangement, can be alleviated by selective deactivation of the stereoelectronic effects that promote the 1,2‐alkyl shift. Stable cyclic Criegee intermediates constrained within a five‐membered ring can be prepared by mild reduction of the respective hydroperoxy peroxyesters (β‐hydroperoxy‐β‐peroxylactones) which were formed in high yields in reaction of β‐ketoesters with BF3?Et2O/H2O2. 相似文献
119.
Controlling Proton and Electron Transfer Rates to Enhance the Activity of an Oxygen Reduction Electrocatalyst 下载免费PDF全文
Rajendra P. Gautam Yi Teng Lee Gabriel L. Herman Cynthia M. Moreno Prof. Dr. Edmund C. M. Tse Prof. Dr. Christopher J. Barile 《Angewandte Chemie (International ed. in English)》2018,57(41):13480-13483
An electrochemical approach is developed that allows for the control of both proton and electron transfer rates in the O2 reduction reaction (ORR). A dinuclear Cu ORR catalyst was prepared that can be covalently attached to thiol‐based self‐assembled monolayers (SAMs) on Au electrodes using azide–alkyne click chemistry. Using this architecture, the electron transfer rate to the catalyst is modulated by changing the length of the SAM, and the proton transfer rate to the catalyst is controlled with an appended lipid membrane modified with proton carriers. By tuning the relative rates of proton and electron transfer, the current density of the lipid‐covered catalyst is enhanced without altering its core molecular structure. This electrochemical platform will help identify optimal thermodynamic and kinetic parameters for ORR catalysts and catalysts of other reactions that involve the transfer of both protons and electrons. 相似文献
120.
Monica M. Schroll Katelyn R. Ludwig Gabriel J. LaBonia Emily L. Herring Amanda B. Hummon 《Journal of the American Society for Mass Spectrometry》2018,29(10):2012-2022
Short-term glucose starvation prior to chemotherapy has the potential to preferentially weaken cancer cells, making them more likely to succumb to treatment, while protecting normal cells. In this study, we used 3D cell cultures of colorectal cancer and assessed the effects of short-term glucose starvation and chemotherapy compared to treatment of either individually. We evaluated both phenotypic changes and protein expression levels. Our findings indicate that the combined treatment results in more significant phenotypic responses, including decreased cell viability and clonogenicity. These phenotypic responses can be explained by the decreased expression of LDHA and 14-3-3 family proteins, which were found only in the combined treatment groups. This study indicates that short-term glucose starvation has the potential to increase the efficacy of current cancer treatment regimes. 相似文献