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排序方式: 共有174条查询结果,搜索用时 578 毫秒
71.
Hanwei Zhao Shunhai Wang Son N. Nguyen S. Gokhan Elci Igor A. Kaltashov 《Journal of the American Society for Mass Spectrometry》2016,27(2):211-219
Transferrin (Tf) is a promising candidate for targeted drug delivery. While development of such products is impossible without the ability to monitor biodistribution of Tf-drug conjugates in tissues and reliable measurements of their levels in blood and other biological fluids, the presence of very abundant endogenous Tf presents a significant impediment to such efforts. Several noncognate metals have been evaluated in this work as possible tracers of exogenous transferrin in complex biological matrices using inductively coupled plasma mass spectrometry (ICP MS) as a detection tool. Placing Ni(II) on a His-tag of recombinant Tf resulted in formation of a marginally stable protein–metal complex, which readily transfers the metal to ubiquitous physiological scavengers, such as serum albumin. An alternative strategy targeted iron-binding pockets of Tf, where cognate Fe(III) was replaced by metal ions known to bind this protein. Both Ga(III) and In(III) were evaluated, with the latter being vastly superior as a tracer (stronger binding to Tf unaffected by the presence of metal scavengers and the retained ability to associate with Tf receptor). Spiking serum with indium-loaded Tf followed by ICP MS detection demonstrated that protein quantities as low as 0.04 nM can be readily detected in animal blood. Combining laser ablation with ICP MS detection allows distribution of exogenous Tf to be mapped within animal tissue cross-sections with spatial resolution exceeding 100 μm. The method can be readily extended to a range of other therapeutics where metalloproteins are used as either carriers or payloads. 相似文献
72.
Mütesir Temel Omer Tayfuroglu Abdulkadir Kocak 《Journal of computational chemistry》2023,44(4):559-569
Here, we investigate the performance of “Accurate NeurAl networK engINe for Molecular Energies” (ANI), trained on small organic compounds, on bulk systems including non-covalent interactions and applicability to estimate solvation (hydration) free energies using the interaction between the ligand and explicit solvent (water) from single-step MD simulations. The method is adopted from ANI using the Atomic Simulation Environment (ASE) and predicts the non-covalent interaction energies at the accuracy of wb97x/6-31G(d) level by a simple linear scaling for the conformations sampled by molecular dynamics (MD) simulations of ligand-n(H2O) systems. For the first time, we test ANI potentials' abilities to reproduce solvation free energies using linear interaction energy (LIE) formulism by modifying the original LIE equation. Our results on ~250 different complexes show that the method can be accurate and have a correlation of R2 = 0.88–0.89 (MAE <1.0 kcal/mol) to the experimental solvation free energies, outperforming current end-state methods. Moreover, it is competitive to other conventional free energy methods such as FEP and BAR with 15-20 × fold reduced computational cost. 相似文献
73.
Senem Karahan Pelin Kose Elif Subasi Huseyin Alp Hamdi Temel 《Transition Metal Chemistry》2008,33(7):849-854
The hitherto unknown complexes, [M2(CO)6(μ-CO)(μ-L)], [M = Cr; 1, Mo; 2, W; 3] and [M2(CO)6(μ-CO)(μ-L′)], [M = Cr; 4, Mo; 5, W; 6] have been synthesized by the photochemical reactions of photogenerated intermediate, M(CO)5THF (M = Cr, Mo, W) with thio Schiff base ligands, N,N′-bis(2-aminothiophenol)-1,4-bis(2-carboxaldehydephenoxy)butane (H
2
L) and N,N′-bis(2-aminothiophenol)-1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane (H
2
L′). The complexes have been characterized by elemental analysis, LC-mass spectrometry, magnetic studies, FT-IR and 1H NMR spectroscopy. The spectroscopic studies show that H
2
L and H
2
L′ ligands are converted to benzothiazole derivatives, L and L′ after UV irradiation and coordinated to the central metal as bridging ligands via the central azomethine nitrogen and sulphur
atoms in 1–6. 相似文献
74.
A new cobalt Schiff-base complex, [Co(L)(OH)(H2O)] (where L = [N,N′-bis(2-aminothiophenol)-1,4-bis(carboxylidene phenoxy)butane), was synthesized and its electrochemical and spectroelectochemical properties were investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and thin-layer spectro-electrochemistry in solutions of dimethyl sulfoxide (DMSO) and dichloromethane (CH2Cl2). The [Co(L)(OH)(H2O)] complex displays two well-defined reversible reduction processes with the corresponding anodic waves. The half-wave potentials of the first and second reduction processes were displayed at E1/2 = 0.08 V and E1/2 = −1.21 V (scan rate: 0.100 Vs−1) in DMSO, and E1/2 = −0.124 V and E1/2 = −1.32 V (scan rate: 0.100 Vs−1) in CH2Cl2. The potentials of the reduction processes in DMSO are shifted toward negative potentials (0.220–0.112 V) compared to those in CH2Cl2. The electrochemical results are assigned to two one-electron reduction processes; [Co(III)L] + −e → [Co(II)L]− and [Co(II)L]− + −e → [Co(I)L]2−. The six-coordination of the complex remains unchanged during the reduction processes and the electron transfer processes were not followed by a chemical reaction upon scan reversal. It was also seen that [Co(L)(OH)(H2O)] was reduced at a more positive potential than the corresponding salen analogs. The shift and reversibility are apparently related to the high degree of electron delocalization of the [Co(L)(OH)(H2O)] complex, having a N2O2S2 donor set and two additional benzene units. Additionally, in situ spectroelectrochemical measurements support Co(III)/Co(II) and Co(II)/Co(I) reversible reduction processes with the observation of the corresponding spectral changes with the applied potentials Eapp = −0.40 and −1.60 V. Application of the spectroelectrochemical results allowed the determination ofE1/2 and n (the number of electrons) from the spectra of the fully oxidized and reduced species in one unified experiment as well. The results obtained by this method are in agreement with those by the CV and DPV methods. 相似文献
75.
76.
77.
Gokhan Temel Binnur Aydogan Nergis Arsu Yusuf Yagci 《Journal of polymer science. Part A, Polymer chemistry》2009,47(11):2938-2947
The general design for the synthesis of AB diblock, and A2B and AB2 star copolymers based on the statistical coupling of poly(styrene) (PSt) and poly (methyl methacrylate) (PMMA) macromolecules containing photoreactive benzophenone is presented. For this purpose, mono- and bifunctional initiators for Atom Transfer Radical Polymerization (ATRP) bearing benzophenone group were synthesized and characterized. End- and mid-chain benzophenone functional PSt and PMMA with low molecular weights were obtained by ATRP using these initiators in the presence of CuBr/N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA) catalytic complex. Poly(styrene-block-methyl methacrylate) (PSt-b-PMMA) copolymers were prepared by photolysis of the solutions containing end functional PSt and PMMA in THF at λ = 350 nm for 60 min in the presence of a hydrogen donor such as N-methyldiethanolamine (NMDEA). The proposed mechanism assumes hydrogen abstraction of photoexcited benzophenone moiety by NMDEA. Ketyl radicals resulting from abstraction reaction undergo radical-radical coupling to form benzpinacol structure at the core. Formation of A2B and AB2 type star copolymers upon irradiation of solutions containing appropriate combinations of end- and mid-chain functional polymers was also demonstrated. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2938–2947, 2009 相似文献
78.
In this study,the electronic transition properties and structural analysis of the metal complexes(Ni(Ⅱ),Co(Ⅱ),Cu(Ⅱ)and Mn(Ⅱ))of three different polymer ligands were performed by using XRF and X-ray diffraction(XRD)techniques,respectively.The structural analysis of the polymers and their complexes were performed by XRD technique and some of the polymers were found to be in the face-centred cubic(fcc)structure.In addition,the values of the present K X-ray intensity ratios are significantly greater than the values reported in literature. 相似文献
79.
In this paper, we consider the balanced unidirectional cyclic layout problem (BUCLP) arising in the determination of workstation locations around a closed loop conveyor system, in the allocation of cutting tools on the sites around a turret, in the positioning of stations around a unidirectional single loop AGV path. BUCLP is known to be NP-Complete. One important property of this problem is the balanced material flow assumption where the material flow is conserved at every workstation. We first develop a branch-and-bound procedure by using the special material flow property of the problem. Then, we propose a dynamic programming algorithm, which provides optimum solutions for instances with up to 20 workstations due to memory limitations. The branch and bound procedure can solve problems with up to 50 workstations. 相似文献
80.
Nonlinear Dynamics - Equation 7 should appear as follows 相似文献