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101.
Jun-ichi Yamada Maki Watanabe Hiroyuki Anzai Hiroyuki Nishikawa Isao Ikemoto Koichi Kikuchi 《Angewandte Chemie (International ed. in English)》1999,38(6):810-813
Metallic behavior down to low temperature is shown by charge transfer salts of BDH-TTP ( 1 ), a structural isomer of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF). In the case of (BDH-TTP)2PF6 this behavior is attributed to the structure, which is made up of κ-type sheets of BDH-TTP donor molecules and sheets of PF6− anions. 相似文献
102.
103.
Kawasaki H Sasaki A Kawashima T Sasaki S Kakehashi R Yamashita I Fukada K Kato T Maeda H 《Langmuir : the ACS journal of surfaces and colloids》2005,21(13):5731-5737
Lyotropic phase behavior of the nonionic and the half-ionized oleyldimethylamine oxide (OlDMAO)/water systems was investigated using polarized light microscopy, small-angle X-ray diffraction, and differential scanning calorimetry. Nonionic OlDMAO formed isotropic micellar solution, nematic, hexagonal, cubic, and lamellar liquid crystalline phases as the surfactant concentration increased. In contrast, half-ionized OlDMAO (i.e., 1:1 mixture of the nonionic and the protonated species) had a greater tendency to form bilayer structures, and the phase diagram became quite similar to those of double-chained ionic surfactants rather than single-chained ones, despite the introduction of positive charges to the nonionic one. The preference of the bilayer structures in the half-ionized OlDMAO was interpreted in terms of the dimers stabilized by the hydrogen bond between the nonionic and protonated species. For alkyldimethylamine oxides with a saturated hydrocarbon chain (CnDMAO, chain length: n = 14, 16, and 18), the phase sequence of lyotropic liquid crystals was hardly affected by the protonation, but an elongation of the cylinders of the hexagonal phase was observed for the half-ionized C14DMAO. Consequently, it can be considered that the dominant bilayer formation of the half-ionized OlDMAO is attributed to the combined effect of the hydrogen-bonded dimer formation and the cis-double-bond configuration of the alkyl chain. 相似文献
104.
Summary
Vacuum Fusion Determination of Micro-quantities of Bulk Gases in Low Carbon Iron Without an Effect of Surface Gases
Micro-quantities of bulk and surface oxygen and hydrogen in low carbon iron was simultaneously determined by the surface-area-variation method using vacuum fusion analysis. Among the difference of three surface treatments, silicon carbide abrasive, electropolishing and hydrogen reduction methods, bulk oxygen and hydrogen were in agreement within their errors, however, surface oxygen and hydrogen were influenced from the surface treatments. Even in the case of electropolishing, which gave the smallest surface oxygen value, bulk oxygen less than 10g/g is needed to discriminate from the surface oxygen. Bulk hydrogen of 0.03g/g was determined without the effect of surface hydrogen in the hydrogen reduction treatment. 相似文献
105.
Masato Kawamoto Yasuyuki Mori Akihiko Tsuge Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2022,60(8):1416-1421
Anionic ring-opening polymerization (ROP) behavior of trans-cyclohexene carbonate (CHC) using metal alkoxides as initiators was investigated. As a result, lithium tert-butoxide-initiated ROP of CHC with a high-monomer concentration (10 M) at low temperature (−15 to −10°C) proceeded to afford a poly(trans-cyclohexene carbonate) (PCHC) without undesired side reactions such as mainly backbiting. The suppression of side reactions enables the control of the molecular weight (Mn = 2400–6100) of PCHC with low molar-mass dispersity values (Mw/Mn = 1.16–1.22). Furthermore, by increasing the feed ratio of the monomer to the initiator, the molecular weight increases proportionally, indicating a controllable polymerization. The results of a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis, a kinetic study, and a chain extension experiment suggested a living nature of this ROP using lithium tert-butoxide. 相似文献
106.
Shahi Imam Reja Yuichiro Hori Takuya Kamikawa Kohei Yamasaki Miyako Nishiura Steven D. Bull Kazuya Kikuchi 《Chemical science》2022,13(5):1419
The ability to monitor proteolytic pathways that remove unwanted and damaged proteins from cells is essential for understanding the multiple processes used to maintain cellular homeostasis. In this study, we have developed a new protein-labeling probe that employs an ‘OFF–ON–OFF’ fluorescence switch to enable real-time imaging of the expression (fluorescence ON) and degradation (fluorescence OFF) of PYP-tagged protein constructs in living cells. Fluorescence switching is modulated by intramolecular contact quenching interactions in the unbound probe (fluorescence OFF) being disrupted upon binding to the PYP-tag protein, which turns fluorescence ON. Quenching is then restored when the PYP-tag–probe complex undergoes proteolytic degradation, which results in fluorescence being turned OFF. Optimization of probe structures and PYP-tag mutants has enabled this fast reacting ‘OFF–ON–OFF’ probe to be used to fluorescently image the expression and degradation of short-lived proteins.An “OFF–ON–OFF” fluorescence probe for real-time imaging of the expression (fluorescence ‘OFF’) and degradation (fluorescence ‘ON’) of short lived PYP-tag proteins in cellular systems. 相似文献
107.
Hiroaki Shimomoto Akira Oda Motoki Kanayama Tomoya Sako Tomomichi Itoh Eiji Ihara Naohiro Hoshikawa Akihiko Koiwai Naoki Hasegawa 《Journal of polymer science. Part A, Polymer chemistry》2016,54(12):1742-1751
Pd‐initiated polymerization and oligomerization of diazo compounds containing a dialkoxyphosphinyl group are described. Polymerization of 2‐dialkoxyphosphinylethyl diazoacetates with π‐allylPdCl‐based initiating systems afforded C? C main chain polymers bearing phosphonate on each main chain carbon atom. The quantitative transformation of the side chain phosphonate to phosphonic acid resulted in the formation of water soluble polymers having the acid groups accumulated around their main chains, although the carbonyl ester linkage in the side chain was cleaved via intramolecular acid‐assisted hydrolysis in water at 80 °C. Pd‐initiated oligomerization of diethyl diazomethylphosphonate yielded an oligomeric product bearing diethoxyphosphiny groups directly attached to its main chain carbons, with unexpected incorporation of azo group in the main chain framework. Hydrolysis of the phosphonate of the oligomer afforded a water‐soluble product, which was revealed to show higher proton conductivity than poly(vinylphosphonic acid) under certain conditions. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1742–1751 相似文献
108.
109.
The liquid-liquid extraction of copper(I) with 12-, 13-, 15- and 16-membered cyclic tetrathio ethers ([n]aneS4, where n represents the total number of carbon and sulphur atoms in the cyclic ligand ring) was examined stoichiometrically using picrate ion (Pic?) for the formation of the ion pair. Copper(I) was extracted with four ligands (L) into 1,2-dichloroethane as the ion-pair compound, [Cu(I)L]+Pic?. The extraction constant, Kex, with each ligand was determined. As the ring size of cyclic tetrathio ethers increases, the log Kex values, including that previously reported for [14]aneS4, increase from 7.7 to 9.4. The value of Δ log Kex, which represents the increase in log Kex due to the addition of one carbon atom to the macrocyclic ring, was large between [13]aneS4 and [14]aneS4 (Δ log Kex=1.0) and small between [14]aneS4 and [15]aneS4 (Δ log Kex=0.1). 相似文献
110.
Interfacial property modulation of thermoresponsive polymer brush surfaces and their interaction with biomolecules 总被引:2,自引:0,他引:2
Nagase K Kobayashi J Kikuchi A Akiyama Y Kanazawa H Okano T 《Langmuir : the ACS journal of surfaces and colloids》2007,23(18):9409-9415
Dense poly(N-isopropylacrylamide) (PIPAAm) brushes were created on silica bead surfaces by surface-initiated atom transfer radical polymerization (ATRP). Interfacial properties of PIPAAm brushes were characterized by thermoresponisve interaction with biomolecules. The grafted amounts of PIPAAm on silica bead surfaces exceeded that from previously reported polymer-hydrogel-modified silica beads prepared by conventional radical polymerization by nearly 1 order of magnitude. Temperature-dependent chromatographic interactions with soluble analytes were modulated by changing the grafted PIPAAm chain lengths. Short PIPAAm-grafted silica beads produce insufficient dehydration and chain aggregation to separate steroids using weak hydrophobic interactions. In contrast, broad unresolved peaks were observed on silica beads column grafted with long PIPAAm chains due to steroid partitioning into thick, densely grafted PIPAAm brush layers. Thus, silica beads column grafted with PIPAAm chains of proper length can demonstrate baseline separation of steroids with relatively high resolution among the tested columns. Relatively longer retention times for steroid analytes were observed on all columns compared to those previously reported for other PIPAAm-grafted silica beads. This indicates that densely PIPAAm-grafted chains enable control of strong hydrophobic interactions with steroids by changing the column temperature. Densely grafted PIPAAm columns were also successful in separating two peptides into two peaks as the column temperature was increased to 40 degrees C. This provides an effective separation alternative for peptides using substantial hydrophobicity without modification of hydrophobic surfaces and/or low mobile phase pH. In conclusion, densely PIPAAm-grafted surfaces exhibit strong, reversible temperature-modulated hydrophobic interactions, facilitating baseline separations of steroids and peptides in aqueous milieu without changes in the mobile phase pH and high ionic strength. 相似文献