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排序方式: 共有524条查询结果,搜索用时 46 毫秒
121.
Piceatannol,(E)-3,3′,4,5′-tetrahydroxy stilbene, a natural polyhydroxy stibene, possesses many biological activities, its synthesis has been reported. We designed another route of its synthesis, which can be controlled more easily. The synthetic product was characterized by elemental analysis,IR,MS and ^1H-NMR. Its analogs were synthesized by the similar method. 相似文献
122.
Zhi Song PIAO Lin WANG* Zhi Zhong ZHAO Institute of Materia Medica Peking Union Medical Collage &Chinese Academy of Medical Sciences Beijing 《中国化学快报》2003,14(11)
3,5,4'-Trimethoxystilbene is the methoxy precursor of a natural product 3,5,4'-trihydro- xystilbene (resveratrol)1 , which was reported to have many biological activities2. 3,5,4'-trimethoxystilbene itself is also a natural product2. We have synthesized 3,5,4'-trimethoxystilbene. In the screening of its anti-tumor activity using three different human cancer cell lines, 3,5,4'-trimethoxystilbene was found to have an IC50 5.91 mol/L for KB, 5.82 mol/L for A2780, 7.08 mol/L for HCT-8, respe… 相似文献
123.
Han LIANG Jing Jian LI* Xiao Dong LI Fei Li TANG Gu YUAN* Department of Chemistry Peking University Beijing The Key Laboratory of Bioorganic Chemistry Molecular Engineering Department of Chemical Biology Peking University Beij 《中国化学快报》2002,13(10)
Distamycin is a naturally occurring antibiotic which binds to the AT rich regions in minor groove of DNA1. We have reported the interaction between the analogs and calf thymus DNA by circular dichroism spectropolarimetry (CD) and isothermal titration calorimetry (ITC)2. Due to the greater sensitivity of fluorescence-based techniques in comparison with CD, we employ the fluorimety to explore the interaction between four new distamycin analogs and DNA from herring sperm. O2NNNOHNNO… 相似文献
124.
《Journal of carbohydrate chemistry》2013,32(4-6):549-581
On the basis of the xylose‐inositol analogy, a series of permeant analogs of D‐myo‐inositol 1,4,5‐trisphosphate (InsP3) have been synthesized by various esterifications of the phosphate groups. Their ability to cross the cell membrane has been tested on vasopressin cells. Very fast liberation of calcium occurs when active analogs are introduced in the extracellular medium on intact cells. Membrane crossing as well as hydrolysis of the phosphate is very rapid using acyloxymethyl esterification of all the phosphate groups. The free compounds behave in the cell like InsP3. One of the analogs prepared this way behaves like vasopressin for rat hepatocyte cells expressing vasopressin receptor. 相似文献
125.
The review summarizes data on the synthesis and properties of analogs of ABBB-and ABAB-type tetrapyrrole macrocycles and their
metal complexes. The structural features of these compounds are discussed. Data on aromaticity and biological properties are
considered.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 663–679, April, 2007. 相似文献
126.
Detecting epistatic interactions, or nonlinear interactive effects of Single Nucleotide Polymorphisms (SNPs), has gained increasing attention in explaining the “missing heritability” of complex diseases. Though much work has been done in mapping SNPs underlying diseases, most of them constrain to 2-order epistatic interactions. In this paper, a method of hypergraph construction and high-density subgraph detection, named HC-HDSD, is proposed for detecting high-order epistatic interactions. The hypergraph is constructed by low-order epistatic interactions that identified using the normalized co-information measure and the exhaustive search. The hypergraph consists of two types of vertices: real ones representing main effects of SNPs and virtual ones denoting interactive effects of epistatic interactions. Then, both maximal clique centrality algorithm and near-clique mining algorithm are employed to detect high-density subgraphs from the constructed hypergraph. These high-density subgraphs are inferred as high-order epistatic interactions in the HC-HDSD. Experiments are performed on several simulation data sets, results of which show that HC-HDSD is promising in inferring high-order epistatic interactions while substantially reducing the computation cost. In addition, the application of HC-HDSD on a real Age-related Macular Degeneration (AMD) data set provides several new clues for the exploration of causative factors of AMD. 相似文献
127.
Dr. Mariia Pushina Sepideh Farshbaf Wakana Mochida Masashi Kanakubo Dr. Ryuhei Nishiyabu Prof. Dr. Yuji Kubo Prof. Dr. Pavel Anzenbacher Jr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(44):11344-11351
The newly prepared fluorescent carboxyamidoquinolines ( 1 – 3 ) and their Zn(II) complexes ( Zn@1-Zn@3 ) were used to bind and sense various phosphate anions utilizing a relay mechanism, in which the Zn(II) ion migrates from the Zn@1-Zn@3 complexes to the phosphate, namely adenosine 5’-triphosphate (ATP) and pyrophosphate (PPi), a process accompanied by a dramatic change in fluorescence. Zn@1-Zn@3 assemblies interact with adenine nucleotide phosphates while displaying an analyte-specific response. This process was investigated using UV-vis, fluorescence, and NMR spectroscopy. It is shown that the different binding selectivity and the corresponding fluorescence response enable differentiation of adenosine 5’-triphosphate (ATP), adenosine 5’-diphosphate (ADP), pyrophosphate (PPi), and phosphate (Pi). The cross-reactive nature of the carboxyamidoquinolines-Zn(II) sensors in conjunction with linear discriminant analysis (LDA) was utilized in a simple fluorescence chemosensor array that allows for the identification of ATP, ADP, PPi, and Pi from 8 other anions including adenosine 5’-monophosphate (AMP) with 100 % correct classification. Furthermore, the support vector machine algorithm, a machine learning method, allowed for highly accurate quantitation of ATP in the range of 5–100 μM concentration in unknown samples with error <2.5 %. 相似文献
128.
Byunghyuck Jung Jungkyu K. Lee Jungnam Kim Eunhye K. Kang Sang Yeong Han Hee‐Yoon Lee Insung S. Choi 《化学:亚洲杂志》2019,14(21):3749-3762
(?)‐Cannabidiol ((?)‐CBD), a non‐psychoactive phytocannabinoid from Cannabis, and its structural analogs have received growing attention in recent years because of their potential therapeutic benefits, including neuroprotective, anti‐epileptic, anti‐inflammatory, anxiolytic, and anti‐cancer properties. (?)‐CBD and its analogs have been obtained mainly based on extraction from the natural source; however, the conventional extraction‐based methods have some drawbacks, such as poor quality control along with purification difficulty. Chemical‐synthetic strategies for (?)‐CBD could tackle these issues, and, additionally, generate novel (?)‐CBD analogs that exhibit advanced biological activities. This review concisely summarizes the historic and recent milestones in the synthetic strategies for (?)‐CBD and its analogs. 相似文献
129.
N. O. Mahmoodi M. Mamaghani A. Ghanadzadeh M. Arvand M. Fesanghari 《Journal of Physical Organic Chemistry》2010,23(3):266-270
Synthesis of several ‘dyes’, analogs of retinal imine visual pigment via nucleophilic attack of some secondary amines to pyridinium salts following precyclic ring‐opening reaction, is discussed. The photochromic properties of these dyes have been studied by UV‐Vis spectroscopy under irradiation of UV light. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
130.
Isabelle Abrunhosa-Thomas 《Tetrahedron》2010,66(25):4434-4440
The preparation and reactivity of some α,α-difluorophosphinates are investigated. Alkylation of H-phosphinates with LiHMDS and ClCF2H gives the corresponding α,α-difluorophosphinates in good yield. Deprotonation of these reagents with alkyllithium or LDA is then studied. Subtle electronic effects translate into significant differences in the deprotonation/alkylation of the two ‘Ciba-Geigy reagents’ (EtO)2CRP(O)(OEt)H (R=H, Me). On the other hand, attempted methylation of difluoromethyl-octyl-phosphinic acid butyl ester resulted in the exclusive alkylation of the octyl chain. Finally, reaction with carbonyl compounds results in the formation of 1,1-difluoro-2-phosphinoyl compounds. 相似文献