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141.
Sergi Jansana Guilhem Coussanes Jordi Puig Faiza Diaba Josep Bonjoch 《Helvetica chimica acta》2019,102(10)
A general procedure is reported for the synthesis of cis ring fused azapolycyclic compounds bearing an all‐carbon quaternary stereocenter at the ring fusion and an adequate functionalization for the assembly of new rings leading to advanced synthetic intermediates for Daphniphyllum alkaloid synthesis. The key carbon?carbon bond‐forming step in this approach is a radical cyclization of an N‐cycloalkenyl trichloroacetamide derivative involving a tetrasubstituted enamide to achieve polyfunctionalized lactams. 相似文献
142.
Hamidreza Enshaei Brenda G. Molina Luis J. del Valle Francesc Estrany Carme Arnan Jordi Puiggalí Núria Saperas Carlos Alemn 《Macromolecular bioscience》2019,19(8)
Ambroxol is a pharmacological chaperone (PC) for Gaucher disease that increases lysosomal activity of misfolded β‐glucocerebrosidase (GCase) while displaying a safe toxicological profile. In this work, different poly(ε‐caprolactone) (PCL)‐based systems are developed to regulate the sustained release of small polar drugs in physiological environments. For this purpose, ambroxol is selected as test case since the encapsulation and release of PCs using polymeric scaffolds have not been explored yet. More specifically, ambroxol is successfully loaded in electrospun PCL microfibers, which are subsequently coated with additional PCL layers using dip‐coating or spin‐coating. The time needed to achieve 80% release of loaded ambroxol increases from ≈15 min for uncoated fibrous scaffolds to 3 days and 1 week for dip‐coated and spin‐coated systems, respectively. Furthermore, it is proven that the released drug maintains its bioactivity, protecting GCase against induced thermal denaturation. 相似文献
143.
Electronic Structure Modulation in an Exceptionally Stable Non‐Heme Nitrosyl Iron(II) Spin‐Crossover Complex
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Lucía Piñeiro‐López Dr. Norma Ortega‐Villar Prof. Dr. M. Carmen Muñoz Dr. Gábor Molnár Dr. Jordi Cirera Prof. Dr. Rafael Moreno‐Esparza Prof. Dr. Víctor M. Ugalde‐Saldívar Dr. Azzedine Bousseksou Prof. Dr. Eliseo Ruiz Prof. Dr. José A. Real 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(36):12741-12751
The highly stable nitrosyl iron(II) mononuclear complex [Fe(bztpen)(NO)](PF6)2 (bztpen=N‐benzyl‐N,N′,N′‐tris(2‐pyridylmethyl)ethylenediamine) displays an S=1/2?S=3/2 spin crossover (SCO) behavior (T1/2=370 K, ΔH=12.48 kJ mol?1, ΔS=33 J K?1 mol?1) stemming from strong magnetic coupling between the NO radical (S=1/2) and thermally interconverted (S=0?S=2) ferrous spin states. The crystal structure of this robust complex has been investigated in the temperature range 120–420 K affording a detailed picture of how the electronic distribution of the t2g–eg orbitals modulates the structure of the {FeNO}7 bond, providing valuable magneto–structural and spectroscopic correlations and DFT analysis. 相似文献
144.
Dr. Miriam Corredor Dr. Daniel Carbajo Cecilia Domingo Dr. Yolanda Pérez Dr. Jordi Bujons Prof. Dr. Angel Messeguer Dr. Ignacio Alfonso 《Angewandte Chemie (International ed. in English)》2018,57(37):11973-11977
Despite heparin being the most widely used macromolecular drug, the design of small‐molecule ligands to modulate its effects has been hampered by the structural properties of this polyanionic polysaccharide. Now a dynamic covalent selection approach is used to identify a new ligand for heparin, assembled from extremely simple building blocks. The amplified molecule strongly binds to heparin (KD in the low μm range, ITC) by a combination of electrostatic, hydrogen bonding, and CH–π interactions as shown by NMR and molecular modeling. Moreover, this ligand reverts the inhibitory effect of heparin within an enzymatic cascade reaction related to blood coagulation. This study demonstrates the power of dynamic covalent chemistry for the discovery of new modulators of biologically relevant glycosaminoglycans. 相似文献
145.
Rodríguez-Ropero F Zanuy D Casanovas J Nussinov R Alemán C 《Journal of chemical information and modeling》2008,48(2):333-343
Conformationally restricted amino acids are promising candidates to serve as basic pieces in redesigned protein motifs which constitute the basic modules in synthetic nanoconstructs. Here we study the ability of constrained cyclic amino acid 1-aminocyclohexane-1-carboxylic acid (Ac6c) to stabilize highly regular beta-helical motifs excised from naturally occurring proteins. Calculations indicate that the conformational flexibility observed in both the ring and the main chain is significantly higher than that detected for other 1-aminocycloalkane-1-carboxylic acids (Acnc, where n refers to the size of the ring) with smaller cycles. Incorporation of Ac6c into the flexible loops of beta-helical motifs indicates that the stability of such excised building blocks as well as the nanoassemblies derived from them is significantly enhanced. Thus, the intrinsic Ac6c tendency to adopt folded conformations combined with the low structural strain of the cyclohexane ring confers the ability to both self-adapt to the beta-helix motif and to stabilize the overall structure by absorbing part of its conformational fluctuations. Comparison with other Acnc residues indicates that the ability to adapt to the targeted position improves considerably with the ring size, i.e., when the rigidity introduced by the strain of the ring decreases. 相似文献
146.
Ruiz E Cirera J Cano J Alvarez S Loose C Kortus J 《Chemical communications (Cambridge, England)》2008,(1):52-54
This theoretical study discusses the interplay of the magnetic anisotropy and magnetic exchange interaction of two Mn6 complexes and suggests that large magnetic anisotropy is not favoured by a high spin state of the ground state. 相似文献
147.
148.
Paital AR Bertolasi V Aromí G Ribas-Ariño J Ray D 《Dalton transactions (Cambridge, England : 2003)》2008,(7):861-864
A perchlorate ligand in the rare mu4-1,1,2,2 binding mode is seen for the first time as the sole support for the assembly of two cationic [Cu II 2L]+ fragments (H3L = a dinucleating ligand) in the formation of a magnetically-exchanged tetranuclear cluster. 相似文献
149.
Escudero-Adán EC Benet-Buchholz J Kleij AW 《Dalton transactions (Cambridge, England : 2003)》2008,(6):734-737
The interaction of Zn(salphen) complex with biologically important structures such as (benz)imidazoles and purine has been studied and revealed in the case of unprotected purine and (benz)imidazole derivatives a demetalated product, whereas for structurally related 1-methyl-(benz)imidazole the formation of 1 : 1 coordination complexes was evidenced by NMR, MS and X-ray crystallography. 相似文献
150.
Zanuy D Flores-Ortega A Casanovas J Curcó D Nussinov R Alemán C 《The journal of physical chemistry. B》2008,112(29):8692-8700
Recently, a potentially powerful strategy based on phage-display libraries has been presented to target tumors via homing peptides attached to nanoparticles. The Cys-Arg-Glu-Lys-Ala (CREKA) peptide sequence has been identified as a tumor-homing peptide that binds to clotted plasmas proteins present in tumor vessels and interstitium. The aim of this work consists of mapping the conformational profile of CREKA to identify the bioactive conformation. For this purpose, a conformational search procedure based on modified simulated annealing combined with molecular dynamics was applied to three systems that mimic the experimentally used conditions: (i) the free peptide; (ii) the peptide attached to a nanoparticle; and (iii) the peptide inserted in a phage display protein. In addition, the free peptide was simulated in an ionized aqueous solution environment, which mimics the ionic strength of the physiological medium. Accessible minima of all simulated systems reveal a multiple interaction pattern involving the ionized side chains of Arg, Glu, and Lys, which induces a beta-turn motif in the backbone observed in all simulated CREKA systems. 相似文献