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71.
Hosseini Fahimeh Mohammadi-Khanaposhtani Maryam Azizian Homa Ramazani Ali Tehrani Maliheh Barazandeh Nadri Hamid Larijani Bagher Biglar Mahmoud Adibi Hossein Mahdavi Mohammad 《Structural chemistry》2020,31(3):999-1012
Structural Chemistry - A new series of 4-oxobenzo[d]1,2,3-triazin-pyridinium-phenylacetamide hybrids 8a–p was designed, synthesized, and screened as the potential cholinesterase inhibitors... 相似文献
72.
Shengfei Jin Hang T. Dang Graham C. Haug Viet D. Nguyen Hadi D. Arman Oleg V. Larionov 《Chemical science》2020,11(34):9101
Construction of C–C bonds at the α-carbon is a challenging but synthetically indispensable approach to α-branched carbonyl motifs that are widely represented among drugs, natural products, and synthetic intermediates. Here, we describe a simple approach to generation of boron enolates in the absence of strong bases that allows for introduction of both α-alkyl and α-aryl groups in a reaction of readily accessible 1,2-dicarbonyls and organoboranes. Obviation of unselective, strongly basic and nucleophilic reagents permits carrying out the reaction in the presence of electrophiles that intercept the intermediate boron enolates, resulting in two new α-C–C bonds in a tricomponent process.α-Branched carboxylic acids and other carbonyls are readily accessed by a metal- and base-free deoxygenative α-alkylation and α-arylation of 1,2-dicarbonyls via boron enolates, resulting in a tricomponent coupling with unconventional electrophiles. 相似文献
73.
Awang K Mukhtar MR Hadi AH Litaudon M Latip J Abdullah NR 《Natural product research》2006,20(6):567-572
The alkaloidal extract of the leaves of Phoebe grandis (nees) merr. have provided two new minor alkaloids; phoebegrandine D (1), a proaporphine-tryptamine dimer, and phoebegrandine E (2), an indoloquinolizidine. This is the first report on the occurrence of an indoloquinolizidine in the Phoebe species. The crude extract also exhibited antiplasmodial activity (IC50<8 microg mL-1). The structures of the novel compounds were elucidated by spectroscopic methods, notably 2D NMR and HRMS. 相似文献
74.
The reaction of cis-[Pt(15NH3)2(H2O) 2] 2+ (3) with N-acetylcysteine [H3accys] was investigated in aqueous solution. In this reaction, the ammine in the platinum complex formed was liberated. A
mono-dentate sulfur-boundplatinum(II) product cis-[Pt(15NH3)2(H2O)(H2accys-S)]+ (7) and six-membered che-late ring complex cis-[Pt(15NH3)2 (Haccys-S,O)] (8) were formed in solution. The dinuclear sulfur-bridged complex 9, giving a broad peak in 15N NMR, was also observed, but only present in very tiny amounts. The mass spectrometry (ES-MS) was undertaken from this re
action, and the product detected was only the dinuclear sulfur bridged platinum species and species related to it by ammine
loss. 相似文献
75.
Taha H Hadi AH Nordin N Najmuldeen IA Mohamad K Shirota O Nugroho AE Piow WC Kaneda T Morita H 《Chemical & pharmaceutical bulletin》2011,59(7):896-897
Pseuduvarines A (1) and B (2), two new dioxoaporphine alkaloids with an amino moiety, were isolated from the stem bark of Pseuduvaria rugosa and their structures were elucidated by combination of 2D-NMR spectroscopic analysis. Pseuduvarines A (1) and B (2) showed cytotoxicity against MCF7, HepG2, and HL-60 (1: IC??, 0.9, 21.7, and >50.0 μM, respectively, 2: IC?? >50.0, 15.7, and 12.4 μM, respectively). 相似文献
76.
A series of allylpalladium dimers having metals connected by binucleating dialkyldithiooxamidate [N(R)SC-CS(R)N](2-) [R = methyl, ethyl, isopropyl, benzyl, isoamyl, (S)-1-(1-phenyl)ethyl, meso-(1-phenyl)ethyl, and rac-(1-phenyl)ethyl] were prepared by reacting the monochelate [(η(3)-allyl)Pd(N(R)SC-CS(R)NH κ-S,S Pd)] with [(η(3)-allyl)PdCl](2) in chloroform. At low temperature (20 °C), the bimetallic complexes [(η(3)-allyl)Pd](2)(μ-dialkyldithiooxamidate κ-N,N' Pd, κ-S,S' Pd') (kinetic compounds) are formed in a short reaction time (10 min). At a higher temperature (50 °C) and a longer reaction time (24 h), the corresponding bimetallic isomers [(η(3)-allyl)Pd](2)(μ-dialkyldithiooxamidate κ-N,S Pd, κ-N',S' Pd') (thermodynamic compounds) are obtained. Both kinetic and thermodynamic compounds can exist as endo or exo isomers, depending on the reciprocal orientation of the allyl cuspids. Both endo and exo isomers are only detectable in solution when the alkyl substituents are chiral alkyl groups. Moreover, diffractometric modeling agrees with the presence of both isomers in the solid state even when the alkyl substituent is an achiral alkyl group. In a chloroform solution, endo and exo isomers undergo isomeric conversion owing to the apparent allyl rotation that follows the Pd-N bond rupture in the (η(3)-allyl)Pd(N^N) frame of kinetic compounds or in the (η(3)-allyl)Pd(N^S) frame of thermodynamic compounds. The dithiooxamidate [N(R)SC-CS(R)N](2-), when engaged in a κ-N,S Pd, κ-N',S' Pd' coordination mode, behaves as a hybrid hemilabile binucleating ligand. At room temperature and in a chloroform solution, the kinetic compounds rearrange into the thermodynamically more stable isomers in about 3 or 4 days. The higher stability of the thermodynamic species was evaluated by means of computational studies in accordance with the maximum hardness principle. Finally, the crystal structures of [(η(3)-allyl)Pd](2)(μ-diethyldithiooxamidate κ-N,S Pd, κ-N',S' Pd'), [(η(3)-allyl)Pd](2)(μ-meso-(1-phenyl)ethyldithiooxamidate κ-N,S Pd, κ-N',S' Pd'), and [(η(3)-allyl)Pd](2)(μ-rac-(1-phenyl)ethyldithiooxamidate κ-N,N' Pd, κ-S,S' Pd') are reported. 相似文献
77.
Ali Reza Ghiasvand Morasaalsadat Nasseri Sara Farsizaeh Mohammad Hadi Meshkatalsadat Reza Sadeghi-Sarabi Shahriar Shadabi Mohammad Borzoei 《Chromatographia》2011,73(9-10):1031-1035
Ultrasound-assisted headspace solid-phase microextraction (UA-HS-SPME) coupled to gas chromatography–mass spectrometry (GC–MS) has been used for analysis of volatile compounds in dry Tagetes minuta L. The highest extraction efficiency was achieved with a 100-μm polydimethylsiloxane (PDMS) fiber. Different experimental conditions, for example, type of fiber coating, sonication time, extraction time and temperature, and desorption time, were investigated. Thirty compounds were identified by use of this UA-HS-SPME–GC–MS method. Comparison of the method with the commonly used hydrodistillation (HD) method showed that the proposed method is simpler, needs much less sample, requires shorter extraction time and lower temperature, has high trapping ability, and extracts more volatile and thermally sensitive compounds. The major components identified by use of the method were e-ocimenone (10.3%), cis-β-ocimene (4.8%), α-terpinolene (8.4%), trans-caryophyllene (19.7%), germacrene-d (10.0%), and camphor (3.6%). 相似文献
78.
This paper presents a method for the construction of a graphene paste electrode (GPE) from reduced graphene oxide (RGO). The GPE was successfully used for the determination of medetomidine. The influence of some experimental variables such as pH, supporting electrolyte, scan rate, and possible interferences were studied. Differential pulse voltammetric (DPV) peak currents of medetomidine increased linearly with its concentration in the range from 0.009 to 2.5 µM. The limit of detection (LOD) and limit of quantitation (LOQ) values for the determination of medetomidine were 2.8 and 9.2 nM, respectively. Also, for the first time, the electroreduction behavior of medetomidine was investigated. 相似文献
79.
Quality assessment of gasoline using comprehensive two‐dimensional gas chromatography combined with unfolded partial least squares: A reliable approach for the detection of gasoline adulteration 下载免费PDF全文
Comprehensive two‐dimensional gas chromatography and flame ionization detection combined with unfolded‐partial least squares is proposed as a simple, fast and reliable method to assess the quality of gasoline and to detect its potential adulterants. The data for the calibration set are first baseline corrected using a two‐dimensional asymmetric least squares algorithm. The number of significant partial least squares components to build the model is determined using the minimum value of root‐mean square error of leave‐one out cross validation, which was 4. In this regard, blends of gasoline with kerosene, white spirit and paint thinner as frequently used adulterants are used to make calibration samples. Appropriate statistical parameters of regression coefficient of 0.996–0.998, root‐mean square error of prediction of 0.005–0.010 and relative error of prediction of 1.54–3.82% for the calibration set show the reliability of the developed method. In addition, the developed method is externally validated with three samples in validation set (with a relative error of prediction below 10.0%). Finally, to test the applicability of the proposed strategy for the analysis of real samples, five real gasoline samples collected from gas stations are used for this purpose and the gasoline proportions were in range of 70–85%. Also, the relative standard deviations were below 8.5% for different samples in the prediction set. 相似文献
80.
Hadi Gholami Dr. Mercy Anyika Jun Zhang Dr. Chrysoula Vasileiou Prof. Dr. Babak Borhan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(27):9235-9239
The absolute stereochemistry of cyanohydrins, derived from ketones and aldehydes, is obtained routinely, in a microscale and derivatization‐free manner, upon their complexation with Zn‐MAPOL, a zincated porphyrin host with a binding pocket comprised of a biphenol core. The host–guest complex leads to observable exciton‐coupled circular dichroism (ECCD), the sign of which is easily correlated to the absolute stereochemistry of the bound cyanohydrin. A working model, based on the ECCD signal of cyanohydrins with known configuration, is proposed. 相似文献