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991.
A stable label-free amperometric immunosensor is presented based on gold nanoparticles and graphene oxide nanocomposites for detection of cardiac troponin-I in the early diagnosis of myocardial infarction. For designing of the sensing platform, firstly the nanocomposites based on GO and AuNPs were prepared and anchored on electrode surfaces. The formed nanocomposites provided a platform with big surface area for loading anti-cTnI capture antibody, and worked as a bridge for fast electron transfer subsequently increased the sensitivity. Moreover, the linkages between AuNP, GO, and electrodes were based on covalent bonding by aryldiazonium salt coupling chemistry, which favors the stability of the sensing interface. Finally, the anti-cTnI detection antibody was immobilized on GO tailored with ferrocene molecules, functioning as the signal reporter for the detection of cTnI. The modification process was monitored using electrochemistry, SEM, XPS. The herein immunosensor demonstrates a good selectivity and high sensitivity against human-cTnI, and is capable of detecting cTnI at concentrations as low as 0.05 ng mL−1, which is 100 times lower than that possible by conventional methods. It is potential to design the portable sensing platform based on AuNPs and GO nanocomposites for future point-of-care diagnostics. 相似文献
992.
Experimental (FT‐IR) and theoretical (DFT) studies on prototropy and H‐bond formation for pyrazine‐2‐amidoxime
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Angelika Głębocka Ewa D. Raczyńska Agnieszka Chylewska Mariusz Makowski 《Journal of Physical Organic Chemistry》2016,29(7):326-335
The results of the first structural studies (with the use of both experimental and theoretical methods) on pyrazine‐2‐amidoxime (PAOX) were shown and discussed. FT‐IR spectra were recorded in different concentrations of the PAOX in apolar solvent to check the possibility of the inter‐ or intramolecular hydrogen‐bond formation. All possible tautomers–rotamers of PAOX were then theoretically considered at the DFT(B3LYP)/6‐311+G** level in vacuo. For selected isomers, calculations were also performed at higher levels of theory {B3LYP/6‐311+G(3df,2p) and G3B3}. Based on the results of DFT calculations, the most stable isomers were found, and their total free energies and infrared spectra were calculated. The energy variation plots for the N8?C7?N9?O10 and N1?C2?C7?N9 dihedral angles were also computed to find two energy barriers, one for E/Z isomerization around the C7?N9 double bond and the other one for rotation of the pyrazinyl ring around the C2?C7 single bond. The results show that the stability of the PAOX isomers strongly depend on their configuration and orientation of the substituents. The possibilities of inter‐ and intramolecular hydrogen bonds were also experimentally and theoretically checked. Finally, a potential of mean force was determined in CHCl3 for a dimer of PAOX with hexamethylphosphoramide. Both, experimental and theoretical results are in agreement. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
993.
Ewa Girejko Luís Machado Agnieszka B. Malinowska Natália Martins 《Mathematical Methods in the Applied Sciences》2016,39(18):5302-5314
We analyze a bounded confidence model, introduced by Krause, on isolated time scales. In this model, each agent takes into account only the assessments of the agents whose opinions are not too far away from its own opinion. We show that the behavior of the model depends strongly on the graininess function μ: If μ takes values in the interval ]0,1], then our discrete time scale model behaves similarly to the classical one, but if μ takes values in ]1,+∞[, then the model has different properties. Simulations are performed to validate the theoretical results. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
994.
Krzysztof Marciniec Jolanta Bafeltowska Maria J. Maślankiewicz Ewa Buszman Stanisław Boryczka 《液相色谱法及相关技术杂志》2016,39(15):702-709
Reversed-phase high-performance liquid chromatography analyses were used for the determination of the retention factor (log k) of a set of quinolinesulfonamides. The analyses utilized a mixture of acetonitrile/water as the mobile phase. The log k values were linearly dependent on the concentration of acetonitrile and extrapolated to 100% water and gave the lipophilicity parameter log kw. The parameter log PHPLC was determined from log kw values using the calibration curve obtained for five standards. The log PHPLC parameters are discussed in terms of structure–lipophilicity relationships. Furthermore, the theoretical lipophilic parameters (log Pcalc) for all compounds were calculated using chemical programs (e.g., Advanced Chemistry Development (ACD/ logP), miLogP, AlogP, ClogP, and Pallas). The determined log PHPLC and calculated log Pcalc values were compared by linear regression analysis. 相似文献
995.
The total chromatic sum of a graph is the minimum sum of colors (natural numbers) taken over all proper colorings of vertices and edges of a graph. We construct infinite families of graphs for which the minimum number of colors to achieve the total chromatic sum is larger than the total chromatic number. 相似文献
996.
Gałdecka Ewa Gałdecki Zdzisław Pruchnik Florian P. Starosta Radosław 《Transition Metal Chemistry》1999,24(1):100-103
The binuclear rhodium(II) complex Na2[Rh2Cl2(OAc)4]· 4H2O has an infinite sheet structure. Binuclear anionic complexes [Rh2Cl2(OAc)4]2– are bound with cationic entities. The Na+ cation has pseudooctahedral coordination and is surrounded by two chloro ligands and two oxygen atoms of bridging acetato ligands of two [Rh2Cl2(OAc)4]2– anions and two water molecules. Both Cl and H2O are bridging ligands involved in formation of the Na+ chains. The remaining water molecules are located between sheets. 相似文献
997.
Chat-Wilk Karolina Rudnik Ewa Włoch Grzegorz Osuch Piotr 《Journal of Solid State Electrochemistry》2022,26(8):1715-1731
Journal of Solid State Electrochemistry - The codeposition of zinc and nickel from slightly acidic chloride, sulfate, and chloride-sulfate solutions containing a gluconate complexing agent was... 相似文献
998.
The importance of electromigration techniques in molecular biology and medicine is increasing rapidly, especially in systematic studies on proteomes and metabolomes. Staphylococcus aureus and Escherichia coli are bacterial species most frequently encountered in human infections, and many serious illnesses can be observed in the hospital environment. In this contribution we proposed a CE method with different modification of internal capillary surface and with monolithic beds as a selective material for determination of bacteria in clinical samples. The electrophoretic separation depends on the differential mobility of bacteria in the capillary and selective interactions between bacterial cells and stationary phases (modified surface, monolithic beads). Proposed procedures could become an effective tool for diagnosis of certain diseases caused by S. aureus and E. coli as well as Proteus vulgaris. 相似文献
999.
The aquation of chromium(III)-isocinchomeronato and quinolinato complexes, mer-[Cr(icaH)3]0 and mer-[Cr(quinH)3]0 (where icaH− and quinH− are N,O-bonded isocinchomeronic and quinolinic acid anion, respectively) was studied in NaOH solutions. The process leads
to successive ligand liberation in the fully deprotonated species. The kinetics of the first ligand liberation were studied
spectrophotometrically in the visible region. A mechanism is proposed in which the rate of the chelate-ring opening at the
Cr–N bond is much faster than the rate of the Cr–O bond breaking. The rate-determining step is described by the rate law:
k
obs1 = k
OH(1) + k
O
Q
2 [OH−], where k
OH(1) and k
O are rate constants of the first ligand liberation from the hydroxo- and oxo-forms of the intermediate, respectively, and
Q
2 is an equilibrium constant between these two protolytic forms. The first pseudo-first-order rate constants (k
obs1) were calculated using SPECFIT software for an A → B → C reaction pattern. The results are compared with those determined
in acidic medium. Kinetics of the second and third ligand liberation were also studied and values of successive pseudo-first-order
rate constants (k
obs2, k
obs3) are [OH−] independent. Effect of chromium(III)-quinolinato and isocinchomeronato complexes on 3T3 fibroblast proliferation was evaluated.
Cytotoxicity of these complexes is low, suggesting they may be promising candidates as novel dietary supplements. 相似文献
1000.
The chromium(III) complexes with a new potential chromium transporting ligand—2,5-pyridinedicarboxylic acid (isocinchomeronic
acid, icaH2):[Cr(icaH)3]0, [Cr(icaH)2 (H2O)2]+ and [Cr(icaH)(H2O)4]2+ (where icaH = N,O-bonded isocinchomeronic acid anion), have been obtained and characterized in solution. The [Cr(icaH)3]0 complex undergoes aquation in acidic media to the diaqua-product. Kinetics of this process was studied spectrophotometrically
in the 0.1–1.0 M HClO4 range, at I = 1.0 M. The first aquation stage, the chelate-ring opening at the Cr–N bond, is a much faster than the second one. The rate
laws are of the form: k
obs = k
1 + k
−1/Q
1[H+] and k
obs = k
2
Q
2[H+]/(1 + Q
2[H+]), where k
1 and k
2 are the rate constants for the chelate-ring opening and the ligand liberation, respectively, k
−1 is the rate constant of the chelate-ring closure, Q
1 and Q
2 are the protonation constants of the pyridine nitrogen and 5-carboxylate group in the one-end bonded intermediate, respectively.
The results are discussed in terms of potential pharmaceutical application of the complex. 相似文献