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131.
Prof. Joe Otsuki Takumi Okumura Dr. Kosuke Sugawa Dr. Shin-ichiro Kawano Prof. Kentaro Tanaka Dr. Takehiro Hirao Prof. Takeharu Haino Yu Jin Lee Seongsoo Kang Prof. Dongho Kim 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(12):4053-4063
Self-assembly of porphyrins is a fascinating topic, not only for mimicking chlorophyll assemblies in photosynthetic organisms, but also for the potential of creating molecular-level devices. Herein, zinc porphyrin derivatives bearing a meta-pyridyl group at the meso position were prepared and their assemblies studied in chloroform. Among the porphyrins studied, one with a carbamoylpyridyl moiety gave a distinct 1H NMR spectrum in CDCl3, which allowed the supramolecular structure in solution to be probed in detail. Ring-current-induced chemical-shift changes in the 1H NMR spectrum, together with vapor-pressure osmometry and diffusion-ordered NMR spectroscopy, among other evidence, suggested that the porphyrin molecules form a trimer with a triangular cone structure. Incorporation of a directly linked porphyrin–ferrocene dyad with the same assembling properties in the assemblies led to a rare example of a light-harvesting/charge-separation system in which an energy gradient is incorporated and reductive quenching occurs. 相似文献
132.
Abstract The conformations of pyridinio-appended β-cyclodextrin (CDP+) and nicotinamide-appended β-cyclodextrin (CDNA+) were studied by NMR spectroscopy. The orientations of the pyridine residue of CDP+ and the nicotinamide residue of CDNA+ were determined by using a combination of NMR spectroscopic techniques. NMR spectra indicate that the shapes of the cavities of CDP+ and CDNA+ were changed after forming complexes. This change depended on the shape of the guest. CDNA+ could separate the 1H resonances at the Cβ position of racemic tryptophan into two sets of resonances for each enantiomer. 相似文献
133.
Hirohito Ikeda Yukiko Sano Tomonori Matsubara Mitsunobu Kawahara Miho Yukawa Masao Fujisawa Eiji Yukawa Hatsumi Aki 《Journal of Thermal Analysis and Calorimetry》2013,113(3):1135-1138
Propericiazine (PCZ) is an antipsychotic agent used for the treatment and the prevention of relapse of schizophrenia. We found that when an oral solution containing PCZ was mixed with a green tea drink, the residual content of PCZ was reduced by forming an insoluble complex between PCZ and tea polyphenol. In this study, the mechanism underlying the incompatibility of PCZ with green tea polyphenol (GTP) in the solution was clarified by isothermal titration microcalorimetry (ITC). Both solutions of 27.4 mM PCZ and 2.2 mM (?)-epigallocatechin gallate (EGCg), which is a main ingredient of GTP, were mixed and then PCZ in the filtrate was reduced to approximately 60 %. According to measurement at 298 K by ITC, PCZ formed an insoluble complex with EGCg at an associate constant (K) of 4.75 × 102 M?1 exothermically, ΔH = ?40.0 kJ mol?1. When (?)-epicatechin gallate (ECg) was used as the GTP, PCZ interacted with ECg with K and ΔH values of 3.74 × 102 M?1 and ?22.1 kJ mol?1, respectively. On the other hand, little heat of the reaction between PCZ and (?)-epigallocatechin or (?)-epicatechin was observed. The results indicated that the main reason for this incompatibility was the formation of an insoluble complex by PCZ and a gallate-type GTP such as EGCg and ECg in the aqueous solution. 相似文献
134.
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136.
Hiroyuki Ishibashi Iwao Takamuro Yo-Ichi Mizukami Maki Irie Masazumi Ikeda 《合成通讯》2013,43(3-4):443-452
Friedel-Crafts acylation of arenes with methylthio- (1) or phenylthio-acetyl chloride (2) provides ready access to α-methylthio- or α-phenylthio-substituted acetophenones. The acyl chlorides 1 and 2 reacted also with organoaluminum reagents to give α-sulfenylated alkanones. 相似文献
137.
Unsymmetrical oxamides are conveniently synthesized in good yields by a new trapping reaction of unstable carbamoyl lithiums with isocyanates. 相似文献
138.
Sulfonylurea derivatives including useful antidiabetics (Tolbutamide, Chlorpropamide) were synthesized in good yields from benzene-sulfonamides with thiocarbamates in the presence of DBU. Thiocarbamates were prepared by the selenium-assisted carbonylation of primary amines with carbon monoxide, sulfur, and methyl iodide under mild conditions. 相似文献
139.
Takumi Kusano Kenta Fujii Masaaki Tabata Mitsuhiro Shibayama 《Journal of solution chemistry》2013,42(10):1888-1901
Aggregation structures of 1-alkyl-3-methylimidazolium based ionic liquids (ILs) in aqueous solution were investigated by small-angle neutron scattering (SANS) from the viewpoint of alkyl chain length, n, and anions (Cl?, Br? and trifluoromethanesulfonate, $ {\text{CF}}_{3} {\text{SO}}_{3}^{ - } $ ). In [C4mIm+]-based IL systems, no noticeable SANS intensity was observed for all of the systems examined here, although aqueous [C4mIm+][ $ {\text{BF}}_{4}^{ - } $ ] solutions show a significant SANS profile originating from concentration fluctuations in the solution (Almasy et al. J Phys Chem B 112:2382–2387, 2008). This suggests that [C4mIm+][Cl?], [C4mIm+][Br?] and [C4mIm+][ $ {\text{CF}}_{3} {\text{SO}}_{3}^{ - } $ ] homogeneously mix with water, unlike the [C4mIm+][ $ {\text{BF}}_{4}^{ - } $ ] system, due to preferential hydration of the ions. In the case of the C n mIm cations with longer alkyl chain lengths (n = 8 and 12), SANS profiles were clearly observed in the aqueous solutions at IL concentrations of C IL > 230 and 20.0 mmol·dm?3, respectively. For aqueous [C8mIm+][Br?] solutions, the asymptotic behavior of the scattering function varied largely from I(q) ~ q ?2 to ~q ?4 with increasing C IL, indicating that the solution changes from an inhomogeneous mixing state to a nano-scale micelle state. Aqueous [C12mIm+][Br?] solutions show a typical SANS profile for micelle formation in solution. It was found from a model-fitting analysis that the structure of the [C12mIm+][Br?] micelle is ellipsoidal, not spherical, in solutions over the C IL range examined here. 相似文献
140.
Masahiro Yodoshi Natsumi Ikeda Naoko Yamaguchi Mana Nagata Noriaki Nishida Kazuaki Kakehi Takao Hayakawa Shigeo Suzuki 《Electrophoresis》2013,34(22-23):3198-3205
We have identified novel CE conditions for the separation of 7‐amino‐4‐methylcoumarin‐labeled monosaccharides and oligosaccharides from glycoproteins. Using a neutrally coated capillary and alkaline borate buffer containing hydroxypropylcellulose and ACN, saccharide derivatives form anionic borate complexes, which move from the cathode to the anode in an electric field and are detected near the anodic end. Excess labeling reagents and other fluorescent products remain at the cathodic end. Fluorimetric detection using an LED as a light source enables determination of monosaccharide derivatives with good linearity between at least 0.4 and 400 μM, may correspond to 140 amol to 140 fmol. The lower LOD (S/N = 5) is only 80 nM in the sample solution (ca. 28 amol). The results were comparable to reported values using fluorometric detection LC. The method was also applied to the analysis of oligosaccharides that were enzymatically released from glycoproteins. Fine resolution enables profiling of glycans in glycoproteins. The applicability of the method was examined by applying it to other derivatives labeled with nonacidic tags such as ethyl p‐aminobenzoate‐ and 2‐aminoacridone‐labeled saccharides. 相似文献