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101.
102.
KazutakeShimada TatsuyaHigashi KunikoMitamura 《色谱》2003,21(6):632-637
Steroids comprise a large group of natural substances that must frequently be monitored in various biological materials. Due to the metabolic versatility of steroid molecules, extremely complex mixtures are often encountered, necessitating the use of a chromatographic procedure prior to measurement. In this article we present our work, that is, the development of analyses of biological steroids (especially vitamin D compounds and neurosteroids) using gas chromatography/mass spectrometry, high-performance liquid chromatography (including inclusion chromatography using cyclodextrin) and liquid chromatography/mass spectrometry. 相似文献
103.
Yuki Marubashi Tatsuro Higashi Shoichiro Hirakawa Seiji Tani Tomoki Erata Mitsuo Takai Jun Kawamata 《Optical Review》2004,11(6):385-387
The molecular chain orientation of mercerized cellulose II was examined by optical second harmonic generation (SHG) measurements. The SHG intensities of several kinds of mercerized cellulose II were found to be much larger than those expected for a structural model with an antiparallel molecular chain orientation as proposed by X-ray studies. This result suggests that the orientation of mercerized cellulose II is parallel as suggested by molecular dynamics simulation. © 2004 The Optical Society of Japan 相似文献
104.
105.
A method is presented for characterizing the family of overall systems reconstructable from a given possibilistic structure system. The technique is elaborated in terms of fuzzy relation equations.It is demonstrated that the reconstruction family of a given structure system is equivalent to the set of solutions of a special type of fuzzy relation equation. The solution set is partially ordered, and contains both minimal solutions and a unique maximum solution. When these elements are identified, all members of the reconstruction family are determined.Another characteristic of the reconstruction family is its reconstruction uncertainty, a measure of which is also developed in this paper. This measure is used to define an identifiability quotient that expresses the degree of confidence with which we may identify a single overall system given a particular structure system. 相似文献
106.
Zheng HW Perez P Auchincloss P Blanis D Bodek A Budd H Eno S Fry CA Harada H Ho YH Kim YK Kumita T Mori T Olsen SL Shaw NM Sill A Thorndike EH Ueno K Imlay R Kirk P Lim J McNeil RR Metcalf W Myung SS Cheng CP Gu P Li J Li YK Ye MH Zhu YC Abashian A Gotow K Hu KP Low EH Mattson ME Piilonen L Sterner KL Lusin S Rosenfeld C Wang AT Wilson S Frautschi M Kagan H Kass R Trahern CG Breedon RE Kim GN Ko W Lander RL Maeshima K Malchow RL Smith JR Stuart D Abe K Fujii Y Higashi Y Kim SK Kurihara Y Maki A 《Physical review D: Particles and fields》1990,42(3):737-747
107.
Tadatomi Nishikubo Atsushi Kameyama Hiroto Kudo Kousuke Tsutsui 《Journal of polymer science. Part A, Polymer chemistry》2002,40(9):1293-1302
New photoreactive calixarene derivatives containing spiro ortho ester groups (calixarenes 3a–3c ) were synthesized by the reaction of 2‐bromomethyl‐1,4,6‐trioxaspiro[4.4]nonane with 2,8,14,20‐tetramethyl‐4,6,10,12,16,18,22,24‐octakis(carboxymethoxy)calix[4]resorcinarene, 5,11,17,23,29,35‐hexamethyl‐37,38,39,40,41,42‐hexakis(carboxymethoxy)calix[6]arene, and 5,11,17,23,29,35,41,47‐octa‐tert‐butyl‐49,50,51,52, 53,54,55,56‐octakis‐(carboxymethoxy)calix[8]arene, which were prepared by the reaction of C‐methylcalix[4]resorcinarene, p‐methylcalix[6]arene, and p‐tert‐butylcalix[8]arene, respectively. The thermal stability of the obtained calixarene derivatives containing spiro ortho ester groups was examined with thermogravimetric analysis, and it was found that these calixarene derivatives had good thermal stability. The photoinitiated cationic polymerization of spiro ortho ester groups in calixarene derivatives 3a–3c was examined with certain photoacid generators in the film state. Interestingly enough, the reaction of calixarene derivatives did not proceed with only photoirradiation; however, the reaction proceeded smoothly when the photoirradiation was followed by heating. Furthermore, calixarene 3a , composed of a C‐methylcalix[4]resorcinarene structure, showed the highest photochemical reactivity in this reaction system. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1293–1302, 2002 相似文献
108.
Conformational structures of solvated cobalt(II) ions in several amides and trimethyl phosphate (TMP) have been studied by the X-ray diffraction method using the isomorphous substitution technique. The amides used are formamide (FA), N-methylformamide (NMF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), and N,N-dimethylpropioamide (DMPA). From the analysis of radial distribution functions around Co2+, the distances from Co2+ to each atom of coordinated solvent molecules were obtained and the coordination numbers were determined to be six, except for DMPA where four-coordinate species coexist. The Co—O bond distances are 2.09(1)–2.11(1) Å for six-coordinate species but is 1.96(2) Å for the four-coordinate species. In the amide solutions the Co—O—C bond angles are 126(3)° (FA), 123(2)° (NMF), 123(2)° (DMF), 134(3)° (DMA), and 137(4)–138(4)° (DMPA). The Co—O—C—N dihedral angles were also estimated to discuss the conformational distortion on the Co2+-amide interactions. For TMP solutions the Co—O—P angle was determined to be 150(4)°, and the conformational structure on the Co2+–TMP interaction is discussed. 相似文献
109.
Hiroaki Saito Kousuke Inoue Keiji Matsumoto Makoto Tadokoro Yukio Nakamura 《Journal of Cluster Science》1998,9(2):145-164
The oxidative addition reaction of 2,6-bis(bromomethyl)pyridine to Ru3(CO)12 gave scarcely soluble {Ru2Br2(-Q)(CO)4}
n
, 1, [Q=C5H3N-2-C(O)CH2-6-CH2] or a mixture of 1 and the mononuclear complex RuBr(Q)(CO)3, 2, [Q=C5H3N-2-C(O)CH2-6-CH2Br] according to the reactant's mole ratio. Further reactions of 1 with some N- and P-donor ligands (L) afforded readily soluble dinuclear complexes, Ru2(-Br)(-Q)Br(CO)
n
(L)
m
[n=4, m=1, L=PPh3
3a, or py 3b; n=3, m=2, L=PPh3
5a, or PPh2(o-tolyl) 5b]. In this paper, the characterization of these products by the elemental analyses and the spectroscopic methods are described. The X-ray crystal structures of Ru2(-Br) (-Q)Br(CO)4(PPh3)(MeOH), 4, which was obtained by crystallization of 3a from MeOH, and of 5a · (2CHCl
3
) are also described. Each of the metal atoms in 4 has a distorted octahedral coordination, while in 5a · (2CHCl
3
) one metal atom takes a distorted octahedral geometry and the other pseudooctahedral, which is completed by presenting a Ru ··· Br secondary bonding interaction. 相似文献
110.
This article describes a pilot plant test, which was carried out to examine the effect of start-up operation conditions on catalytic performance in the commercial hydrotreating equipment. From the simulated several pilot tests, it was found that the operation conditions of this commercial equipment were very severe and the hydrogen supply to the catalyst active site was critical. When the heavy residue containing large amount of asphaltene was supplied at the start of run (SOR) in the commercial equipment, the permanent adsorption of carbonaceous deposit on the active site should cause leading the catalyst deactivation. 相似文献