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31.
The functionalized pyranosyl hetero-olefins , and received a remarkable diastereoselective addition of methyllithium to form adducts, one of which was introduced into a possible synthetic intermediate as for maytansine () along Scheme I. 相似文献
32.
Cao B Hasegawa M Okada K Tomiyama T Okazaki T Suenaga K Shinohara H 《Journal of the American Chemical Society》2001,123(39):9679-9680
33.
M. Okada 《Journal of Radioanalytical and Nuclear Chemistry》1974,20(1):135-138
Known intensities of X-rays emitted from radioactive nuclides have been plotted against atomic number, and a distinct correlation
has been found only for EC-decay type nuclides, as follows: 2.75 Z1.06>X>0.507 Z1.06, and Xmost probable=1.18 Z1.06, where X is the absolute percentage and Z is the atomic number of the decay product. 相似文献
34.
Evaporation behavior of water from aqueous dispersions of multihollow particles prepared by the stepwise alkali/acid method 总被引:1,自引:0,他引:1
In order to clarify the formation mechanism of multihollow structures inside styrene–methacrylic acid copolymer particles
prepared by the stepwise alkali/acid method, which we proposed in 1990, the evaporation behavior of water from aqueous dispersions
of the original carboxylated particles and those after the alkali treatment and the stepwise alkali/acid treatments was examined.
It is concluded that the particle after the alkali treatment had a number of small water pools inside.
Received: 22 February 2001 Accepted: 20 June 2001 相似文献
35.
Kenji Okada 《Journal of Molecular Structure》1996,380(3):223-233
The crystal and molecular structures of 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A, BPA) (1), benzyl 4-hydroxybenzoate (2), 1,7-bis(4-hydroxyphenylthio)-3,5-dioxaheptane (3) and 4-hydroxyphenyl 4-isopropoxyphenyl sulfone (4) have been determined by X-ray crystal structure analysis. Theoretical calculations of the steric hindrance and semiempirical quantum chemical calculations to determine the color characteristics have been carried out. It is clear that the energy barriers for the variation of the orientation of phenol group in 1 to 4 are due to steric hindrance caused by the other moiety and the peak profiles are due to repulsive interactions of the other moiety. Net atomic charges on the hydrogen of the OH group are larger than those on the other atoms in the molecules. This high electron charge of the para orientation will cause the different thermosensitivity and stabilization. 相似文献
36.
Minoru Wakimoto 《Communications in Mathematical Physics》1986,104(4):605-609
The aim of this note is to show that the affine Lie algebraA
1
(1)
has a natural family , ,v of Fock representations on the spaceC[x
i,y
j;i andj ], parametrized by (,v) C
2. By corresponding the highest weight
, of , to each (,), the parameter spaceC
2 forms a double cover of the weight spaceC0C –1 with singularities at linear forms of level –2; this number is (–1)-times the dual Coxeter number. Our results contain explicit realizations of irreducible non-integrable highest wieghtA
1
(1)
-modules for generic (,v). 相似文献
37.
Masahiro?Okada Takumi?Matoba Masayoshi?OkuboEmail author 《Colloid and polymer science》2003,282(2):193-197
The influence of nonionic emulsifier, included inside styrene-methacrylic acid copolymer [P(S-MAA)] particles during emulsion copolymerization, on the formation of multihollow structure inside the particles via the alkali/cooling method (proposed by the authors) was examined in comparison to emulsifier-free particles. It was clarified that the nonionic emulsifier included inside the P(S-MAA) particles eased the formation of multihollow structure.Part CCL of the series studies on suspension and emulsion 相似文献
38.
Kondo T Kaneko Y Taguchi Y Nakamura A Okada T Shiotsuki M Ura Y Wada K Mitsudo TA 《Journal of the American Chemical Society》2002,124(24):6824-6825
Pyranopyrandiones were prepared by a novel ruthenium-catalyzed carbonylative dimerization of cyclopropenones via C-C bond cleavage. For example, treatment of dipropylcyclopropenone with a catalytic amount of Ru3(CO)12 and NEt3 in THF under 15 atm of carbon monoxide at 140 degrees C for 20 h gave a novel functional monomer, 3,4,7,8-tetrapropylpyrano[6,5-e]pyran-2,6-dione, in an isolated yield of 81%. Unsymmetrically substituted pyranopyrandiones were also obtained by ruthenium-catalyzed carbonylative coupling of cyclopropenones with alkynes under similar reaction conditions. 相似文献
39.
Liposomes prepared from synthetic amphiphiles. I. Their technetium labeling and stability 总被引:1,自引:0,他引:1
In order to apply liposomes prepared from synthetic amphiphiles containing amino acid residues to radiopharmaceuticals, their labeling with 99Tc or 99mTc and stability in saline or in serum were investigated. These liposomes were highly labeled by embedding stearylamine-diethylenetriamine pentaacetic acid as a ligand of technetium. The labeling was more efficient at pH 7.0 than at pH 4.0 or 8.5. Among these technetium-labeled liposomes tested, liposomes containing the alanine residue were stable in saline or in 50% serum at 37 degrees C for at least 24 h, in contrast to liposomes (phosphatidylcholine: cholesterol = 1:1 molar ratio) whose stability had been enhanced by adding cholesterol. 相似文献
40.
Ken-Ichi Ito Masamichi Nishimura Minoru Sashio Masahiro Tsunooka 《Journal of polymer science. Part A, Polymer chemistry》1994,32(11):2177-2185
It was found that amines were formed efficiently by the photolysis of O-acyloximes followed by hydrolysis in polystyrene films and the relationship between structures of O-acyloximes and yields of amines were investigated. O-phenylacetyl acetophenone oxime (PaApO), O-pivaloyl acetophenone oxime (PApO), and O-benzoyl acetophenone oxime (BApO) as monofunctional O-acyloximes and O,O′-succinyl diacetophenone oxime (SDApO) and O,O′-glutaryl diacetophenone oxime (GDApO) as bifunctional O-acyloximes were examined. The yields of amines for PaApO and SDApO under N2 were ca. 70%, which was the highest among O-acyloximes examined in this experiment. On the other hand, the yields for PApO, BApO, and GDApO were less than 15% and it was verified that the hydrogen abstraction by imino radicals via 6-membered cyclic intermediates resulted in the lowering of yields. Although the effect of oxygen under photolysis on the yields of amine for PaApO was negligible under 50% conversion of PaApO, the yield decreased with further increase in the conversion and was 50% at 90% conversion. © 1994 John Wiley & Sons, Inc. 相似文献