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排序方式: 共有335条查询结果,搜索用时 15 毫秒
321.
Dicopper(II) Metallacyclophanes with Electroswitchable Polymethyl‐Substituted para‐Phenylene Spacers
Dr. Jesús Ferrando‐Soria María Castellano Dr. Rafael Ruiz‐García Dr. Joan Cano Prof. Dr. Miguel Julve Prof. Dr. Francesc Lloret Prof. Dr. Catalina Ruiz‐Pérez Dr. Jorge Pasán Dr. Laura Cañadillas‐Delgado Dr. Donatella Armentano Dr. Yves Journaux Dr. Emilio Pardo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):12124-12137
322.
Giomi D Alfini R Micoli A Calamai E Faggi C Brandi A 《The Journal of organic chemistry》2011,76(22):9536-9541
1-(2-Pyridyl)-2-propen-1-ol, obtained by vinylation of commercially available picolinaldehyde, resulted a good starting material for the synthesis of the indolizidine skeleton. In particular, a simple process involving bromination, reduction, and nucleophilic substitution (via elimination and addition) allowed an easy conversion of the starting material into (±)-lentiginosine in ~27% overall yield. 相似文献
323.
Paula Escamilla Marta Viciano-Chumillas Rosaria Bruno Donatella Armentano Emilio Pardo Jesús Ferrando-Soria 《Molecules (Basel, Switzerland)》2021,26(13)
We present a novel bio-friendly water-stable Zn-based MOF (1), derived from the natural amino acid L-serine, which was able to efficiently photodegrade water solutions of brilliant green dye in only 120 min. The total degradation was followed by UV-Vis spectroscopy and further confirmed by single-crystal X-ray crystallography, revealing the presence of CO2 within its channels. Reusability studies further demonstrate the structural and performance robustness of 1. 相似文献
324.
325.
A highly diastereoselective Diels-Alder reaction between cyclopentadiene and ethyl (Z)-2-N-Boc-amino-3-nitroacrylate in neat conditions affords the ethyl 2-t-butoxycarbonylamino-3-endo-nitro-bicyclo[2.2.1]hept-5-ene-2-exo-carboxylate: a new constrained carbocyclic amino acid. Catalytic hydrogenation of this cycloadduct gave the corresponding reduced norbornane derivative. A preliminary investigation into the chemistry of these two amino acids was performed. In particular, the epimerization to their corresponding 3-exo-nitro compounds by treatment both with acid and base was studied. From this study, valuable information on the endo/exo process at the C-3 carbon atom, as well as on the stability of the different stereomers, was obtained. The stability is closely related to the presence or the absence of the double bond in the ring and to the substitution pattern. Finally, deprotection of the amino acid function has been performed. 相似文献
326.
327.
Capitani D Yethiraj A Burnell EE 《Langmuir : the ACS journal of surfaces and colloids》2007,23(6):3036-3048
We report a detailed analysis of deuteron NMR spectra of micellar, lamellar, cubic, and hexagonal mesophases in the aqueous non-ionic surfactant system C(12)E(6)/water. Samples are prepared with and without shear. Particular attention is paid to an interesting temperature-driven phase sequence that includes all of the above phases that are studied before and after shear parallel or perpendicular to the magnetic field direction. Surprising memory effects are found across mesophase transitions. These memory effects provide clues to the structure of the various phases. 相似文献
328.
Bonifacio A Finaurini S Krafft C Parapini S Taramelli D Sergo V 《Analytical and bioanalytical chemistry》2008,392(7-8):1277-1282
The multivariate algorithm hierarchical cluster analysis is applied to sets of resonance Raman spectra collected from human erythrocytes infected with the malaria parasite Plasmodium falciparum. The images obtained yield information about the distribution of hemoglobin and hemozoin (or malaria pigment) within the parasitized cells and about their molecular structure. This method has the advantage of conveying more information than other imaging approaches based on resonance Raman spectroscopy, and it is a promising tool to study the hemozoin formation process and its interaction with antimalarial drugs within unstained, well-preserved parasites. 相似文献
329.
Valeria Di Tullio Noemi Proietti Marco Gobbino Donatella Capitani Roberto Olmi Saverio Priori Cristiano Riminesi Elisabetta Giani 《Analytical and bioanalytical chemistry》2010,396(5):1885-1896
As is well known, the deterioration of wall paintings due to the capillary rise of water through the walls is a very widespread
problem. In this paper, a study of microclimate monitoring, unilateral nuclear magnetic resonance (NMR), and evanescent-field
dielectrometry (EFD) was applied to map non-destructively, in situ, and in a quantitative way the distribution of the moisture
in an ancient deteriorated wall painting of the eleventh century. Both unilateral NMR and EFD are quite new, fully portable,
and non-destructive techniques, and their combination is absolutely new. The approach reported here is proposed as a new analytical
protocol to afford the problem of mapping, non-destructively, the moisture in a deteriorated wall painting in a hypogeous
building such as that of the second level of St. Clement Basilica, Rome (Italy), where the use of IR thermography is impaired
due to the environmental conditions, and the gravimetric tests are forbidden due to the preciousness of the artifact. The
moisture distribution was mapped at different depths, from the very first layers of the painted film to a depth of 2 cm. It
has also been shown how the map obtained in the first layers of the artwork is affected by the environmental conditions typical
of a hypogeous building, whereas the maps obtained at higher depths are representative of the moisture due to the capillary
rise of water from the ground. The quantitative analysis of the moisture was performed by calibrating NMR and EFD signals
with purposely prepared specimens. This study may be applied before and after performing any intervention aimed at restoring
and improving the state of conservation of this type of artwork and reducing the dampness or extracting salts (driven by the
variation of moisture content) and monitoring the effectiveness of the performed interventions during the time. This protocol
is applicable to any type of porous material. 相似文献
330.
Summary As(III), As(V) and organic arsenic in water are determined by differential pulse polarography. As (III) is directly determined in 2M HCl as supporting electrolyte. Total inorganic arsenic [As (III) + As(V)] is measured after reduction of electro-inactive As(V) with sodium sulphite. Total arsenic is determined after oxidative treatment of the water residue with potassium permanganate and magnesium nitrate, and reduction of arsenic with sodium sulphite. Organic arsenic is evaluated by difference. The efficiency of the whole procedure is 78–80% and its detection limit is 1g/l. The relative standard deviation is better than ±1.5% at 50g/l. Interferences due to heavy metals are overcome by removing them by anionexchange or pre-electrolysis with a mercury cathode.
Differential-puls-polarograpbische Bestimmung von anorganischem und organischem Arsen in natürlichen Wässern
Zusammenfassung As (III), As(V) und organisches Arsen in Wässern wurden differentialpuls-polarographisch bestimmt. As (III) wurde direkt in 2 M HCl als Trägerelektrolyt bestimmt. Das anorganische Gesamtarsen [As(III) und As(V)] wurde nach Reduktion des elektro-inaktiven As(V) mit Natriumsulfit gemessen. Nach der oxydativen Behandlung des Wasserrückstandes mit KMnO4 und Magnesiumnitrat und nach Reduktion des Arsens mit Natriumsulfit wurde das Gesamtarsen bestimmt, und das organisch gebundene Arsen durch Differenzbildung ermittelt. Die Ausbeute des gesamten Verfahrens beträgt 78–80%, seine Erfassungsgrenze 1g/l Die relative Standardabweichung ist besser als ±1,5% bei 50g/l. Störungen durch Schwermetalle werden entweder durch deren Entfernung mittels Anionen-austauscher oder durch vorhergehende Elektrolyse mit einer Quecksilberelektrode beseitigt.相似文献