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51.
A new and efficient method of converting acid hydrazides 1 to the corresponding N,N′‐diacylhydrazines 2 under microwave irradiation and in solvent‐free conditions has been described. 相似文献
52.
Susanna Branion 《合成通讯》2013,43(15):2121-2127
We report in detail the preparation of two substituted terephthalic acids: 2‐sulfomethylterephthalic acid (1) and 2‐phosphonoterephthalic acid (2). Efficient, short syntheses have been developed for both compounds. They are potentially useful monomers for construction of acid‐pendant polymer chains. 相似文献
53.
Cl3CCONH2/PPh3 was a versatile reagent to convert carboxylic acids into their corresponding acid chlorides. This intermediate was clearly confirmed by spectroscopic methods (IR, 1H, 13C NMR). This one-pot reaction of in situ acid chloride generated with various alcohols successfully furnished the corresponding esters in moderate to excellent yields. 相似文献
54.
55.
Dr. Fangping Ren Ji Xian Zhaowei Jia Zhichun Chen Hongjun Fu Prof. Dr. Rui Wang Prof. Dr. Wen-Dao Chu Prof. Dr. Xiaobo Pan Jincai Wu 《Angewandte Chemie (International ed. in English)》2023,62(44):e202306759
To synthesize high molecular weight poly(phenolic ester) via a living ring-opening polymerization (ROP) of cyclic phenolic ester monomers remains a critical challenge due to serious transesterification and back-biting reactions. Both phenolic ester bonds in monomer and polymer chains are highly active, and it is difficult so far to distinguish them. In this work, an unprecedented selectively bifunctional catalytic system of tetra-n-butylammonium chloride (TBACl) was discovered to mediate the syntheses of high molecular weight salicylic acid-based copolyesters via a living ROP of salicylate cyclic esters (for poly(salicylic methyl glycolide) (PSMG), Mn=361.8 kg/mol, Ð<1.30). Compared to previous catalysis systems, the side reactions were suppressed remarkably in this catalysis system because phenolic ester bond in monomer can be selectively cleaved over that in polymer chains during ROP progress. Mechanistic studies reveal that the halide anion and alkyl-quaternaryammonium cation work synergistically, where the alkyl-quaternaryammonium cation moiety interacts with the carbonyl group of substrates via non-classical hydrogen bonding. Moreover, these salicylic acid-based copolyesters can be recycled to dimeric monomer under solution condition, and can be recycled to original monomeric monomers without catalyst under sublimation condition. 相似文献
56.
Xueting Zhou Qingqin Huang Jiami Guo Dr. Lei Dai Prof. Dr. Yixin Lu 《Angewandte Chemie (International ed. in English)》2023,62(45):e202310078
Chiral α,α-diaryl ketones are structural motifs commonly present in bioactive molecules, and they are also valuable building blocks in synthetic organic chemistry. However, catalytic asymmetric synthesis of α,α-diaryl ketones bearing a tertiary stereogenic center remains largely unsolved. Herein, we report a catalytic de novo enantioselective synthesis of α,α-diaryl ketones from simple alkynes via chiral phosphoric acid (CPA) catalysis. A broad range of enolizable α,α-diaryl ketones are prepared in good yields and with excellent enantioselectivities. The described protocol also serves as an efficient deuteration method for the preparation of enantiomerically enriched deuterated α,α-diaryl ketones. Using the methodology reported, bioactive molecules, including one of the best-selling anti-breast cancer drugs, tamoxifen, are readily synthesized. 相似文献
57.
Deokhee Kang Do-Wook Kim Joo-Chan Kim Prof. Hee-Sung Park 《Angewandte Chemie (International ed. in English)》2023,62(7):e202214815
Demand for peptide-based pharmaceuticals has been steadily increasing, but only limited success has been achieved to date. To expedite peptide-based drug discovery, we developed a general scheme for cell-based screening of cyclic peptide inhibitors armed with a user-designed warhead. We combined unnatural amino acid incorporation and split intein-mediated peptide cyclization techniques and integrated a yeast-based colorimetric screening assay to generate a new scheme that we call the custom-designed warhead-armed cyclic peptide screening platform (CWCPS). This strategy successfully discovered a potent inhibitor, CY5-6Q, that targets human histone deacetylase 8 (HDAC8) with a KD value of 15 nM. This approach can be a versatile and general platform for discovering cyclic peptide inhibitors. 相似文献
58.
Dr. Satyadeep Waiba Kakoli Maji Mamata Maiti Prof. Dr. Biplab Maji 《Angewandte Chemie (International ed. in English)》2023,62(10):e202218329
Herein, we report a straightforward synthesis of valuable α-hydroxycarboxylic acid molecules via an acceptorless dehydrogenative coupling of ethylene glycol and primary alcohols. A bench-stable manganese complex catalyzed the reaction, which is scalable, with the product being isolated with high yields and selectivities under mild conditions. The protocol is environmentally benign, producing water and hydrogen gas as the only byproducts. Methanol can also be used as a C1 source for producing the platform molecule lactic acid, with a high turnover of >104. The methodology was also used to functionalize alcohols derived from natural products and fatty acids. Furthermore, it was applied for synthesizing α-amino acid, α-thiocarboxylic acid, and several drugs and bioactive molecules, including endogenous metabolites, Danshensu, Enalapril, Lisinopril, and Rosmarinic acid. Preliminary mechanistic studies were performed to shed light on the mechanism involved in the reaction. 相似文献
59.
Dr. Amitosh Sharma Dr. Jaewoong Lim Seonghwan Lee Dr. Seungwan Han Dr. Junmo Seong Prof. Dr. Seung Bin Baek Prof. Dr. Myoung Soo Lah 《Angewandte Chemie (International ed. in English)》2023,62(29):e202302376
A few metal–organic frameworks (MOFs), which typically use strong acids as proton sources, display superprotonic conductivity (≈10−1 S cm−1); however, they are rare due to the instability of MOFs in highly acidic conditions. For the first time, we report superprotonic conductivity using a moderately acidic guest, zwitterionic sulfamic acid (HSA), which is encapsulated in MOF-808 and MIL-101. HSA acts not only as a proton source but also as a proton-conducting medium due to its extensive hydrogen bonding ability and zwitterion effect. A new sustained concentration gradient method results in higher HSA encapsulation compared to conventional methods, producing 10HSA@MOF-808-(bSA)2 and 8HSA@MIL-101. These MOFs show impressive superprotonic conductivity of 2.47×10−1 and 3.06×10−1 S cm−1, respectively, at 85 °C and 98 % relative humidity, and maintain stability for 7 days. 相似文献
60.
Dr. Mengyi Xiong Dr. Yuting Wu Dr. Gezhi Kong Whitney Lewis Dr. Zhenglin Yang Hanxiao Zhang Li Xu Ying Liu Qin Liu Prof. Xuhua Zhao Prof. Xiao-Bing Zhang Prof. Yi Lu 《Angewandte Chemie (International ed. in English)》2023,62(37):e202308086
DNA-based probes have gained significant attention as versatile tools for biochemical analysis, benefiting from their programmability and biocompatibility. However, most existing DNA-based probes rely on fluorescence as the signal output, which can be problematic due to issues like autofluorescence and scattering when applied in complex biological materials such as living cells or tissues. Herein, we report the development of bioluminescent nucleic acid (bioLUNA) sensors that offer laser excitation-independent and ratiometric imaging of the target in vivo. The system is based on computational modelling and mutagenesis investigations of a genetic fusion between circular permutated Nano-luciferase (NLuc) and HaloTag, enabling the conjugation of the protein with a DNAzyme. In the presence of Zn2+, the DNAzyme sensor releases the fluorophore-labelled strand, leading to a reduction in bioluminescent resonance energy transfer (BRET) between the luciferase and fluorophore. Consequently, this process induces ratiometric changes in the bioluminescent signal. We demonstrated that this bioLUNA sensor enabled imaging of both exogenous Zn2+ in vivo and endogenous Zn2+ efflux in normal epithelial prostate and prostate tumors. This work expands the DNAzyme sensors to using bioluminescence and thus has enriched the toolbox of nucleic acid sensors for a broad range of biomedical applications. 相似文献