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排序方式: 共有178条查询结果,搜索用时 15 毫秒
71.
Samuel Danishefsky Kenward Vaughan Robert C. Gadwood Kazuo Tsuzuki James P. Springer 《Tetrahedron letters》1980,21(27):2625-2628
A remakable reaction of the substituted bicyclo [3,3,0] oct-3-ene-2-one () with the sodium enolate of malonic ester is described. 相似文献
72.
Finite temperature corrections to classical kink free energies for the sine-Gordon and ø4 chains are obtained analytically by means of the transfer integral method. These corrections reveal that kink excitations cause a Schottky-type anomaly of specific heat at low temperatures. The numerical results of Schneider and Stoll are explained qualitatively. 相似文献
73.
1,3-Dimethyl-4-iminopteridin-2-one, 1,3-dimethylpteridine-2,4-dione, 1-methylpteridine-2,4-dione, 4-alkoxy-1-methylpteridin-2-one, and 4-alkylamino-1-methylpteridin-2-one were synthesized from diaminomaleonitrile (DAMN) through pyrazine-2,3-dicarbonitrile. The synthetic procedures consist of the condensation of DAMN with glyoxal, the nucleophilic substitution of pyrazine-2,3-dicarbonitrile with methylamine, the reaction of 3-methylaminopyrazine-2-carbonitrile with electrophiles such as methyl isocyanate and methyl chloroformate in the presence of sodium hydride, and the transformation of 3-(methoxycarbonylmethyl)aminopyrazine-2-carbonitrile into the pteridine derivatives. 相似文献
74.
Seiji Yamaguchi Kunihiro Tsuzuki Yoshie Sannomiya Yutaka Oh-Hira Yoshiyuki Kawase 《Journal of heterocyclic chemistry》1989,26(2):285-287
Some benzofuro[3,2-b]quinoline derivatives 1a-d and 3a were synthesized by condensation of 2-amino-benzaldehyde, 2-aminoacetophenone, 2-aminobenzophenone, isatin, or 2-aminobenzoic acid with 3(2H)-benzofuranone. The benzofuroquinolinone 3a was also obtained from 2-aminobenzoic acid and phenoxy-acetyl chloride in two steps and converted to 10-chloro derivative 1e . Similarly, some 8-halobenzofuro[3,2-b]-quinoline derivatives 1d,e and 3a (X = F, Cl, Br, I) were synthesized from 5-haloisatin or 2-amino-5-halo-benzoic acid. And benzofuro[3,2-b]quinolines 1a-e thus obtained were converted to corresponding N-oxides 2 . 相似文献
75.
Kodama K Ushida N Mokhtarani A Paolone VS Volk JT Wilcox JO Yager PM Edelstein RM Freyberger AP Gibaut DB Lipton RJ Nichols WR Potter DM Russ JS Zhang Y Jang HI Kim JY Lim IT Pac MY Baller BR Stefanski RJ Nakazawa K Tasaka S Choi YS Chung KH Kim DC Park IG Song JS Yoon CS Chikawa M Abe T Fujii T Fujioka G Fujiwara K Fukushima H Hara T Takahashi Y Taruma K Tsuzuki Y Yokoyama C Chang SD Cheon BG Cho JH Kang JS Kim CO Kim KY Kim TY Lee JC Lee SB Lim GY Nam SW Shin TS Sim KS Woo JK Isokane Y 《Physical review letters》1991,66(14):1819-1822
76.
Yoriko Sonoda Seiji Tsuzuki Nobuyuki Tamaoki Midori Goto 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(3):o196-o200
The crystal structures of the four E,Z,E isomers of 1‐(4‐alkoxyphenyl)‐6‐(4‐nitrophenyl)hexa‐1,3,5‐triene, namely (E,Z,E)‐1‐(4‐methoxyphenyl)‐6‐(4‐nitrophenyl)hexa‐1,3,5‐triene, C19H17NO3, (E,Z,E)‐1‐(4‐ethoxyphenyl)‐6‐(4‐nitrophenyl)hexa‐1,3,5‐triene, C20H19NO3, (E,Z,E)‐1‐(4‐nitrophenyl)‐6‐(4‐n‐propoxyphenyl)hexa‐1,3,5‐triene, C21H21NO3, and (E,Z,E)‐1‐(4‐n‐butoxyphenyl)‐6‐(4‐nitrophenyl)hexa‐1,3,5‐triene, C22H23NO3, have been determined. Intermolecular N⋯O dipole interactions between the nitro groups are observed for the methoxy derivative, while for the ethoxy derivative, two adjacent molecules are linked at both ends through N⋯O dipole–dipole interactions between the N atom of the nitro group and the O atom of the ethoxy group to form a supramolecular ring‐like structure. In the crystal structures of the n‐propoxy and n‐butoxy derivatives, the shortest intermolecular distances are those between the two O atoms of the alkoxy groups. Thus, the nearest two molecules form an S‐shaped supramolecular dimer in these crystal structures. 相似文献
77.
Dr. Atsushi Sakai Dr. Eisuke Ohta Dr. Yasunori Matsui Dr. Seiji Tsuzuki Prof. Dr. Hiroshi Ikeda 《Chemphyschem》2016,17(24):4033-4036
The photoluminescence (PL) properties of a metal‐free organoboron complex, bis(4‐iodobenzoyl)methanatoboron difluoride ( 1BF2 ), were elucidated. At room temperature, 1BF2 emits blue fluorescence (FL) in nBuCl upon photoexcitation. In contrast, crystals of 1BF2 emit green PL comprised of FL and phosphorescence (PH). The room‐temperature PH of crystalline 1BF2 is a consequence of 1) suppression of thermal deactivation of the S1 and T1 excited states and 2) enhancement of intersystem crossing (ISC) from the S1 to T2 or T1. The results of X‐ray crystallographic and theoretical studies supported the proposal that the former (1) is a result of intermolecular interactions caused by π‐stacking in the rigid crystal packing structure of 1BF2 . The latter (2) is an effect of not only the heavy‐atom effect of iodine, but also the continuous π‐stacking alignment of 1BF2 molecules in crystals, which leads to a forbidden S1→S0 transition and a small energy gap between the S1 and T2 or T1. 相似文献
78.
Saori Tsuzuki Prof. Dr. Taichi Kano 《Angewandte Chemie (International ed. in English)》2023,62(16):e202300637
Chiral sulfimides, the aza-analogues of sulfoxides, are valuable compounds in organic synthesis and medicinal chemistry. Herein, we report an efficient method for preparing chiral sulfimides from easily available enantioenriched sulfinamides. The key step of this method is a stereospecific oxygen-selective alkylation of enantioenriched sulfinamides, which is accomplished by using isopropyl iodide, K2CO3, and DMPU. The resulting chiral sulfinimidate esters are transformed to chiral sulfimides by the nucleophilic addition of the Grignard reagents under simple conditions. This transformation enables access to the enantioenriched diaryl or dialkyl sulfimides bearing two similar carbon substituents, which are difficult to synthesize by previous methods. 相似文献
79.
Seki S Umebayashi Y Tsuzuki S Hayamizu K Kobayashi Y Ohno Y Kobayashi T Mita Y Miyashiro H Terada N Ishiguro S 《Chemical communications (Cambridge, England)》2008,(43):5541-5543
An unusual ionic conduction phenomenon related to the phase transition of a novel phosphonium-cation-based room-temperature ionic liquid (RTIL) is reported; we found that in the phase change upon cooling, a clear increase in ionic conductivity was seen as the temperature was lowered, which differs from widely known conventional RTILs; clearly, our finding of abnormality of the correlation between temperature change and ionic conduction is the first observation in the electrolyte field. 相似文献
80.
Horikoshi S Tsuzuki J Sakai F Kajitani M Serpone N 《Chemical communications (Cambridge, England)》2008,(37):4501-4503
The Urushibara Ni (U-Ni) hydrogenation catalyst and some modified forms, and for comparison Raney-Ni, were subjected to conventional (oil bath) and MW heating, and subsequently characterized by electron dispersive X-ray analysis (EDX), by BET surface area, and by scanning electron microscopy (SEM); yields of the catalyzed hydrogenation of acetophenone to 1-phenylethanol in 2-propanol by one of the modified forms (U-Ni-B) were greatly improved (from 68% to 95%). 相似文献