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71.
Increasing the Chemical‐Shift Dispersion of Unstructured Proteins with a Covalent Lanthanide Shift Reagent 下载免费PDF全文
Dr. Christoph Göbl Moritz Resch Dr. Madeleine Strickland Christoph Hartlmüller Martin Viertler Dr. Nico Tjandra Prof. Dr. Tobias Madl 《Angewandte Chemie (International ed. in English)》2016,55(47):14847-14851
The study of intrinsically disordered proteins (IDPs) by NMR often suffers from highly overlapped resonances that prevent unambiguous chemical‐shift assignments, and data analysis that relies on well‐separated resonances. We present a covalent paramagnetic lanthanide‐binding tag (LBT) for increasing the chemical‐shift dispersion and facilitating the chemical‐shift assignment of challenging, repeat‐containing IDPs. Linkage of the DOTA‐based LBT to a cysteine residue induces pseudo‐contact shifts (PCS) for resonances more than 20 residues from the spin‐labeling site. This leads to increased chemical‐shift dispersion and decreased signal overlap, thereby greatly facilitating chemical‐shift assignment. This approach is applicable to IDPs of varying sizes and complexity, and is particularly helpful for repeat‐containing IDPs and low‐complexity regions. This results in improved efficiency for IDP analysis and binding studies. 相似文献
72.
73.
John GH May I Sarsfield MJ Collison D Helliwell M 《Dalton transactions (Cambridge, England : 2003)》2007,(16):1603-1610
The reaction between [UO2(ReO4)2.H(2)O] and two equivalents of either tri-n-butyl phosphine oxide (TBPO) or tri-iso-butyl phosphate (TiBP) results in the formation of [UO2(mu2-ReO4)(ReO4)(TBPO)2]2 (1) and [UO2(mu2-ReO4)(ReO4)(TiBP)2]2 (2) respectively. Both complexes crystallise as two structurally similar centrosymmetric dimers, the cores containing two uranyl moieties linked by bridging perrhenates. Two P=O donor ligands and one monodenatate perrhenate complete the pentagonal bipyramidal coordination sphere at each metal centre. Both complexes have also been characterised in the solid state by vibrational and absorption spectroscopy. Solution spectroscopic characterisation indicates that both perrhenate and phosphine oxide (1) or phosphate (2) remain coordinated, although it is not possible to state conclusively that the dimeric species remain intact. A low resolution structural study of a minor product from the reaction that yielded revealed a monomeric complex with only monodentate perrhenate coordination, [UO2(ReO4)2(H2O)(TiBP)2] (2'). These results represent the first structural evidence for the bridging coordination mode of perrhenate on coordination to an actinide and yields further insight into the possible solvent phase pertechnetate complexes that may exist in PUREX process phosphate rich solvent. 相似文献
74.
Does a high UV environment ensure adequate vitamin D status? 总被引:1,自引:0,他引:1
Kimlin M Harrison S Nowak M Moore M Brodie A Lang C 《Journal of photochemistry and photobiology. B, Biology》2007,89(2-3):139-147
This study assesses the Vitamin D status of 126 healthy free-living adults aged 18-87 years, in southeast Queensland, Australia (27 degrees S) at the end of the 2006 winter. Participants provided blood samples for analysis of 25(OH)D (the measure of an individual's Vitamin D status), PTH, Calcium, Phosphate, and Albumin, completed a questionnaire on sun-protective/sun-exposure behaviours, and were assessed for phenotypic characteristics such as skin/hair/eye colour and BMI. We found that 10.2% of the participants had serum 25(OH)D levels below 25 nmol/l (considered deficient) and a further 32.3% had levels between 25 nmol/l and 50 nmol/l (considered insufficient). Our results show that low levels of 25(OH)D can occur in a substantial proportion of the population at the end of winter, even in a sunny climate. 25(OH)D levels were higher amongst those who spent more time in the sun and lower among obese participants (BMI>30) than those who were not obese (BMI<30). 25(OH)D levels were also lower in participants who had black hair, dark/olive skin, or brown eyes, when compared with participants who had brown or fair hair, fair skin, or blue/green eyes. No associations were found between 25(OH)D status and age, gender, smoking status, or the use of sunscreen. 相似文献
75.
Sañudo EC Muryn CA Helliwell MA Timco GA Wernsdorfer W Winpenny RE 《Chemical communications (Cambridge, England)》2007,(8):801-803
Cyclic octanuclear complexes, each containing seven group 13 metals and one d-block metal are reported and preliminary physical characterisation of the compounds discussed. 相似文献
76.
Shaw R Laye RH Jones LF Low DM Talbot-Eeckelaers C Wei Q Milios CJ Teat S Helliwell M Raftery J Evangelisti M Affronte M Collison D Brechin EK McInnes EJ 《Inorganic chemistry》2007,46(12):4968-4978
We report the synthesis, by solvothermal methods, of the tetradecametallic cluster complexes [M14(L)6O6(OMe)18Cl6] (M=FeIII, CrIII) and [V14(L)6O6(OMe)18Cl6-xOx] (L=anion of 1,2,3-triazole or derivative). Crystal structure data are reported for the {M14} complexes [Fe14(C2H2N3)6O6(OMe)18Cl6], [Cr14(bta)6O6(OMe)18Cl6] (btaH=benzotriazole), [V14O6(Me2bta)6(OMe)18Cl6-xOx] [Me2btaH=5,6-Me2-benzotriazole; eight metal sites are VIII, the remainder are disordered between {VIII-Cl}2+ and {VIV=O}2+] and for the distorted [FeIII14O9(OH)(OMe)8(bta)7(MeOH)5(H2O)Cl8] structure that results from non-solvothermal synthetic methods, highlighting the importance of temperature regime in cluster synthesis. Magnetic studies reveal the {Fe14} complexes to have ground state electronic spins of S相似文献
77.
Matthew Brewis Guy J. Clarkson Victoria Goddard Madeleine Helliwell Andrea M. Holder Neil. B. McKeown 《Angewandte Chemie (International ed. in English)》1998,37(8):1092-1094
Nonscattering glasses that are indefinitely stable with respect to crystallization can be prepared from the title compounds. In these solid solutions, the dendritic substituents effectively suppress interactions between the phthalocyanine units (see the structure depicted on the right). 相似文献
78.
79.
Jacqueline M. Thorpe Roy L. Beddoes David Collison C. David Garner Madeleine Helliwell Jeremy M. Holmes Peter A. Tasker 《Angewandte Chemie (International ed. in English)》1999,38(8):1119-1121
A tetranuclear iron cluster is the principal component of the purple coatings produced by treating a mild steel surface with a salicylaldoxime corrosion inhibitor. This was shown by comparison of the spectroscopic data with those of the cluster [{Fe(salH)(HsalH)}4], which was obtained from FeCl3 and salicylaldoxime (H2salH) and has a distorted tetrahedral arrangement of FeIII atoms coordinated by terminal (1−) and bridging (2−) salicylaldoximate ligands (the central core of the cluster is depicted). 相似文献
80.
Robert E. Berry Elaine M. Armstrong Roy L. Beddoes David Collison S. Nigar Ertok Madeleine Helliwell C. David Garner 《Angewandte Chemie (International ed. in English)》1999,38(6):795-797
Fly agaric accumulate vanadium in the form of amavadin, whose structure has been elucidated (see picture for the crystal structure). Amavadin contains one VIV center coordinated to two (S,S)-hidpa3− ligands (H3hidpa=2,2′-(hydroxyimino)dipropionic acid) through one η2-NO− group and two unidentate carboxylato groups from each ligand. The arrangement of the two η2-NO− groups leads to a chiral vanadium center, which has been characterized in both the Λ and Δ forms. The carboxylato groups of the amavadin anions bind cations, for example, Ca2+ ions, and/or become involved in hydrogen bonding. 相似文献