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排序方式: 共有885条查询结果,搜索用时 125 毫秒
881.
He Q Insler J Muramatsu H Park CS Thorndike EH Yang F Coan TE Gao YS Artuso M Blusk S Butt J Li J Menaa N Mountain R Nisar S Randrianarivony K Sia R Skwarnicki T Stone S Wang JC Zhang K Bonvicini G Cinabro D Dubrovin M Lincoln A Asner DM Edwards KW Briere RA Ferguson T Tatishvili G Vogel H Watkins ME Rosner JL Adam NE Alexander JP Cassel DG Duboscq JE Ehrlich R Fields L Gibbons L Gray R Gray SW Hartill DL Heltsley BK Hertz D Jones CD Kandaswamy J Kreinick DL Kuznetsov VE Mahlke-Krüger H 《Physical review letters》2008,100(9):091801
We present measurements of D--> KS0 pi and D--> KL0 pi branching fractions using 281 pb(-1) of psi(3770) data at the CLEO-c experiment. We find that B(D0--> KS0 pi 0) is larger than B(D0--> KL0 pi 0), with an asymmetry of R(D0)=0.108+/-0.025+/-0.024. For B(D+--> KS0 pi+) and B(D+--> KL0 pi+), we observe no measurable difference; the asymmetry is R(D+)=0.022+/-0.016+/-0.018. The D0 asymmetry is consistent with the value based on the U-spin prediction A(D0--> K0 pi 0)/A(D0--> K0 pi 0)=-tan2 theta C, where theta C is the Cabibbo angle. 相似文献
882.
Reactivity Tuning of Metal-Free Artificial Photoenzymes through Binding Site Specific Bioconjugation
Thomas Kuckhoff Dr. Richard C. Brewster Dr. Calum T. J. Ferguson Dr. Amanda G. Jarvis 《European journal of organic chemistry》2023,26(13):e202201412
The design and development of artificial metal-free photoenzymes aims to combine the selectivity of enzymatic reactions with the benefits of modern synthetic photocatalysts. Removing the need for rare earth metals and allowing for milder reaction conditions, leading to a more sustainable catalytic system. Here, we present the design of a novel artificial photoenzyme by integrating an organophotocatalytic moiety based on a donor-acceptor design into a steroid carrier protein (SCP-2L). SCP-2L possesses a hydrophobic tunnel facilitating substrate binding in aqueous media. The photocatalyst was site-selectively bound to three SCP-2L variants, possessing a non-native cysteine residue strategically placed around the hydrophobic tunnel of the protein. The three modified photoenzymes were shown to be selective for the oxidation of organic sulfides giving up to 192 turnovers. 相似文献
883.
Hannah J. Dokken Brandon L. Frenette Dr. Michael J. Ferguson Prof. Dr. Eric Rivard 《欧洲无机化学杂志》2023,26(26):e202300202
We report the synthesis and reactivity of the geminal-linked fluorene-derived P/B frustrated Lewis pair (FLP) iPr2P(C13H8)BCy2 ( 1 ). Compound 1 displays anomalous behavior towards small molecules, acting as a “masked” FLP. This behavior stems from significant polarization of the B−C(fluorene) bond in 1 , as identified by density functional theory (DFT) computations. We exploit this B−C bond polarity through reactions with PhPCl2, H3N ⋅ BH3, and iPrNH2, demonstrating P−Cl and N−H bond activation, respectively. 相似文献
884.
Brandon L. Frenette Jonathan Trach Dr. Michael J. Ferguson Prof. Dr. Eric Rivard 《Angewandte Chemie (International ed. in English)》2023,62(10):e202218587
We report phosphinidenes (PR) stabilized by an intramolecular frustrated Lewis pair (FLP) chelate. These adducts include the parent phosphinidene, PH, which is accessed via thermolysis of coordinated HPCO. The reported FLP-PH species acts as a springboard to other phosphorus-containing compounds, such as FLP-adducts of diphosphorus (P2) and InP3. Our new adducts participate in thermal- or light-induced phosphinidene elimination (of both PH and PR, R=organic group), transfer P2 units to an organic substrate, and yield the useful semiconductor InP at only 110 °C from solution. 相似文献
885.
Rong Li Julian Heuer Thomas Kuckhoff Katharina Landfester Calum T. J. Ferguson 《Angewandte Chemie (International ed. in English)》2023,62(17):e202217652
Pseudo-homogeneous polymeric photocatalysts are an emerging class of highly efficient and tunable photocatalytic materials, where the photocatalytic centers are easily accessible. The creation of highly efficient photocatalytic materials that can be rapidly separated and recovered is one of the critical challenges in photocatalytic chemistry. Here, we describe pH-responsive photocatalytic nanoparticles that are active and well-dispersed under acidic conditions but aggregate instantly upon elevation of pH, enabling easy recovery. These responsive photocatalytic polymers can be used in various photocatalytic transformations, including CrVI reduction and photoredox alkylation of indole derivative. Notably, the cationic nature of the photocatalyst accelerates reaction rate of an anionic substrate compared to uncharged species. These photocatalytic particles could be readily recycled allowing multiple successive photocatalytic reactions with no clear loss in activity. 相似文献