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71.
Spontaneous alternating copolymerization of isobutoxyallene with 4-phenyl-1,2,4-triazoline-3,5-dione
Shin-Ichi Yamamoto Fumio Sanda Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2001,39(10):1564-1571
The spontaneous copolymerization of isobutoxyallene ( 1 ) with 4-phenyl-1,2,4-triazoline-3,5-dione ( 2 ) was carried out to afford a copolymer with a number-average molecular weight of 5900–10,300. The copolymer consisted of a 2,3-polymerization unit of 1 and a NN polymerization unit of 2 , maintaining an alternating character regardless of the monomer feed ratio. The corresponding copolymerization of 1 with 2 in the presence of methanol afforded the adduct of the compounds without the polymer, indicating the generation of a zwitterion of 1 and 2 . © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1564–1571, 2001 相似文献
72.
Kanyiva KS Kashihara N Nakao Y Hiyama T Ohashi M Ogoshi S 《Dalton transactions (Cambridge, England : 2003)》2010,39(43):10483-10494
A combination of Ni(cod)(2) and PCyp(3) is found to be an effective catalyst for chemoselective activation of the C-H bond of fluoroarenes over C-F bonds followed by insertion of alkynes to allow direct alkenylation of the electron-deficient arenes. The characteristics of the reactions are: a C-H bond ortho to a fluorine substituent is selectively activated; the reactivity of fluorobenzenes is roughly proportional to the number of fluorine atoms. The reaction conditions tolerate a broad range of both alkynes and fluoroarenes containing both electron-withdrawing and -donating groups, thus allowing efficient synthesis of a variety of substituted ethenes containing a fluoroaryl motif in high regio- and stereoselective manners. Mechanistic studies including both labeling experiments and stoichiometric reactions reveal that oxidative addition of C-H bonds in fluoroarenes to nickel(0) is kinetically highly facile whereas that of C-F bonds is thermodynamically favoured. 相似文献
73.
Toriyama T Nakao A Yamaki Y Nakao H Murakami Y Hasegawa K Isobe M Ueda Y Ushakov AV Khomskii DI Streltsov SV Konishi T Ohta Y 《Physical review letters》2011,107(26):266402
Synchrotron x-ray diffraction experiment shows that the metal-insulator transition occurring in a ferromagnetic state of a hollandite K(2)Cr(8)O(16) is accompanied by a structural distortion from the tetragonal I4/m to monoclinic P112(1)/a phase with a √2×√2×1 supercell. Detailed electronic structure calculations demonstrate that the metal-insulator transition is caused by a Peierls instability in the quasi-one-dimensional column structure made of four coupled Cr-O chains running in the c direction, leading to the formation of tetramers of Cr ions below the transition temperature. This provides a rare example of the Peierls transition of fully spin-polarized electron systems. 相似文献
74.
Shin-Ichi Ohno Katsutoshi Furukawa Masamitsu Taguchi Hideki Namba Hiroshi Watanabe 《Radiation Physics and Chemistry》1999,55(5-6):503-506
Experimental data on the spatial distribution of the energy deposited around an energetic heavy ion, from 1 MeV proton to 5.9 MeV/n uranium ion, which have been reported in the literature were documented to obtain a scaled radial dose distribution; (β/Z*)2 D(Z*, β,t)=200 (for t=0–1), 200/t2 (for t=1tc), and 200 tc/t3 (for t>tc) where Z* and β are the effective charge and velocity relative to c, the velocity of light, of the incident ion, respectively, D the dose in unit of Gy, t the radial distance in unit of nm, tc the critical distance empirically determined.
Then, if we know the yield of any chemical reaction as a function of dose from the results of experiments using γ-radiations or fast electrons or theoretical calculations, we can calculate the probability for the yield of the chemical reaction in the system bombarded with a heavy ion of the effective charge Z* and velocity β. The results of the present calculation of the LET-values and of G(Fe3+) in the ferrous sulfate acidic solution are presented and compared with reported experimental results. 相似文献
75.
Mitsuhiro T. Nakao Yoshitaka Watanabe 《Journal of Computational and Applied Mathematics》1994,50(1-3):401-410
This paper is an extension of the preceding study (Nakao, this journal, 1991) in which we described a numerical verification method of the solution for one-space dimensional parabolic problems, to the several-space dimensional case. Here, numerical verification means the automatic proof of the existence of solutions to the problems by some numerical techniques on a computer. We reformulate the verification condition for nonlinear parabolic initial boundary value problems using the fixed-point problem of a compact operator on certain function spaces. As in the preceding study based upon a simple C0 finite-element approximation and its constructive a priori error estimates, a numerical verification procedure is presented with some numerical examples. 相似文献
76.
Shin-Ichi Ohta 《Proceedings Mathematical Sciences》2017,127(5):833-855
We continue our study of geometric analysis on (possibly non-reversible) Finsler manifolds, based on the Bochner inequality established by Ohta and Sturm. Following the approach of the \(\Gamma \)-calculus of Bakry et al (2014), we show the dimensional versions of the Poincaré–Lichnerowicz inequality, the logarithmic Sobolev inequality, and the Sobolev inequality. In the reversible case, these inequalities were obtained by Cavalletti and Mondino (2015) in the framework of curvature-dimension condition by means of the localization method. We show that the same (sharp) estimates hold also for non-reversible metrics. 相似文献
77.
Much attention has been paid to the cross-coupling reaction of organosilicon compounds due to their stability, non-toxicity, and natural abundance of silicon. In addition, the silicon-based cross-coupling has many advantages over other cross-coupling protocols. Successful examples of the silicon-based cross-coupling reaction are reviewed, focusing especially on the advances made in the last decade. Having had a number of highly effective palladium catalysts developed mainly for other cross-coupling reactions, the development of the silicon-based protocol owes heavily to the design of organosilicon reagents which effectively undergo transmetalation, a key elemental step of the silicon-based cross-coupling reaction. This tutorial review thus classifies various organosilicon reagents depending on substituents on silicon and surveys their cross-coupling reactions with various electrophiles. 相似文献
78.
Nakao Hayashi Pavel I. Naumkin 《Nonlinear Analysis: Theory, Methods & Applications》2011,74(18):6950-6964
We study the global in time existence of small solutions to the nonlinear Schrödinger equation with quadratic interactions (0.1) We prove that if the initial data u0 satisfy smallness conditions in the weighted Sobolev norm, then the solution of the Cauchy problem (0.1) exists globally in time. Furthermore, we prove the existence of the usual scattering states and find the large time asymptotics of the solutions. 相似文献
79.
Watanuki S Matsuura K Tomura Y Okada M Okazaki T Ohta M Tsukamoto S 《Chemical & pharmaceutical bulletin》2011,59(8):1029-1037
A series of 1-isopropyl-1,2,3,4-tetrahydroisoquinoline derivatives were synthesized and their bradycardic activities were evaluated in isolated guinea pig right atria. Structure-activity relationship studies revealed that the introduction of an appropriate substituent and its position on the 1,2,3,4-tetrahydroisoquinoline ring are essential for potent in vitro activity. Furthermore, the tether between the piperidyl moiety and the terminal aromatic ring is important for potent antihypertensive activity. Oral administration of 6-fluoro-1-isopropyl-2-{[1-(2-phenylethyl)piperidin-4-yl]carbonyl}-1,2,3,4-tetrahydroisoquinoline (3b) to spontaneously hypertensive rats (SHR) elicited antihypertensive effects without inducing reflex tachycardia, which is often caused by traditional L-type Ca2? channel blockers. 相似文献
80.
Sano S Okubo Y Handa A Nakao M Kitaike S Nagao Y Kakegawa H 《Chemical & pharmaceutical bulletin》2011,59(7):885-888
Isoliquiritigenin [ILG, (E)-1] was readily prepared via the Horner-Wadsworth-Emmons reactions using β-ketophosphonates 5a, b. An improved protocol for the synthesis of (E)-1 via the Claisen-Schmidt condensation was also presented. 相似文献