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61.
Shokyoku Kanaoka Masahiko Minoda Mitsuo Sawamoto Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1990,28(5):1127-1136
Amphiphilic block polymers of vinyl ethers (VEs). $\rlap{--} [{\rm CH}_{\rm 2} {\rm CH}\left( {{\rm OCH}_{\rm 2} {\rm CH}_{\rm 2} {\rm NH}_{\rm 2} } \right)\rlap{--} ]_m \rlap{--} [{\rm CH}_{\rm 2} {\rm CH}\left( {{\rm OR}} \right)\rlap{--} ]_n \left( {{\rm R: }n{\rm - C}_{{\rm 16}} {\rm H}_{{\rm 33}} ,{\rm }n{\rm - C}_{\rm 4} {\rm H}_{\rm 9} ;m \simeq 40,{\rm n} = 1 - 10} \right)$ were prepared, each of which consists of a hydrophilic segment with pendant primary amino groups and a hydrophobic poly(alkyl VE) segment. Their precursors were obtained by the HI/I2-initiated sequential living cationic polymerization of an alkyl VE and a VE with a phthalimide pendant (CH2 = CHOCH2CH2Im; Im; phthalimide group), where the segment molecular weights and compositions (m/n ratio) could be controlled by regulating the feed ratio of two monomers and the concentration of hydrogen iodide. Hydrazinolysis of the imide functions gave the target polymers which were readily soluble in water under neutral conditions at room temperature. These amphiphilic block polymers lowered the surface tension of their aqueous solutions (0.1 wt%, 25°C) to a minimum ? 30 dyn/cm when the hydrophobic pendant R was n-C4H9 (n = 4–9). The polymers with n-C4H9 pendants in the hydrophobic segment exhibited a higher surface activity than those with n-C16 H33 pendants. The surface activity of the polymers also depended on the pH of the polymer solutions; the surface activity increased in more basic solutions where the ionization of the amino group (? NH2)2? NH3⊕) is suppressed. 相似文献
62.
Masahiko Takahashi Tomoko Gunji Akiko Ichikawa 《Journal of heterocyclic chemistry》2002,39(5):1029-1033
Reactions of 1,2‐dihydro‐4H‐3,1‐benzothiazine‐2,4‐dithiones (trithioisatoic anhydrides) 3 with N‐substi‐tuted benzylamines 9 gave 1,2‐dihydroquinazoline‐4‐thiones 10 , o‐thioureidodithiobenzoic acid 11 , o‐aminothiobenzamides 12 , 2‐amino‐3,1‐benzothiazine‐4‐thiones 13 , or quinazoline‐2,4‐dithiones 14 , depending on the kinds of amine and the reaction solvent. On the other hand, reaction of 3 with trialkyl phosphites afforded dialkyl (1,2‐dihydro‐2‐thioxo‐4H‐3,1‐benzothiazin‐4‐yl)phosphonates 18 . 相似文献
63.
Fukuji Higashi Shin-Ichi Ogata Yasuhiro Aoki 《Journal of polymer science. Part A, Polymer chemistry》1982,20(8):2081-2087
Poly(p-phenyleneterephthalamide) of high molecular weight was obtained when the polycondensation of terephthalic acid and p-phenylenediamine was carried out in N-methylpyrrolidone (NMP) that contained dissolved CaCl2 and LiCl in the presence of pyridine. The molecular weight of the polymer obtained varied with the amount of pyridine relative to the metal salts and with the molar ratios of CaCl2 to LiCl, the maximum ηinh value of 4.5 being obtained under the conditions Py/(CaCl2 + LiCl) ≈ 2.5 (mol/mol), CaCl2/LiCl ≈ 1.2 (mol/mol), and LiCl + CaCl2 ≈ 4 g. Among the solvents tested, NMP was significantly effective for the reaction. Polycondensations of several combinations of other dicarboxylic acids and diamines were carried out with limited success. 相似文献
64.
Mitsuru Ueda Toshitaka Koyama Motokazu Mano Masahiko Yazawa 《Journal of polymer science. Part A, Polymer chemistry》1989,27(3):751-762
Ethyl α-hydroxymethylacrylate (EHMA) was synthesized and homopolymerized in bulk and in solution. The poly(EHMA) is readily soluble in alcohol, acetone, tetrahydrofuran, and methylene chloride at room temperature. Intramolecular lactone formation occurred when poly(EHMA) was heated to 180–230°C. The kinetics of EHMA homopolymerization was investigated in ethyl acetate, using α,α′-azobisisobutylonitrile as an initiator. The rate of polymerization Rp was expressed by Rp = k[AIBN]0.50[EHMA]1.4 and the overall activation energy was calculated as 71.9 kJ/mol. Kinetic constants for EHMA polymerization were obtained as follows: kp/k = 0.17L0.9mol?0.9s?0.5; 2fkd = 1.5 × 10?5 s?1. The relative reactivity ratios of EHMA(M2) copolymerization with styrene (r1 = 0.472, r2 = 0.564) in ethyl acetate were obtained. Applying the Q-e scheme led to Q = 0.84 and e = 0.35 for EHMA. 相似文献
65.
Isoelectric focusing of catalase from acatalasemic mouse and human blood, and cultured human skin fibroblasts 总被引:1,自引:0,他引:1
Hemolysates of normal, heterozygous hypocatalasemic and acatalasemic mice and of Japanese acatalasemic subjects were separated into three fractions, A, B and C, by DEAE-cellulose column chromatography, and pI values of A, B and C fractions were determined by isoelectric focusing. The pI value of catalase in the A, B and C fractions increased in the order of normal, hypocatalasemic and acatalasemic mouse blood. The results obtained from Japanese acatalasemic blood samples showed that the pI values of catalase in the A, B and C fractions were similar to those in normal blood. Catalase in Japanese acatalasemic cultured skin fibroblasts was also analyzed by isoelectric focusing. The pI values of catalase in the extract from the cultured skin acatalasemic fibroblasts was similar to that in normal fibroblasts. 相似文献
66.
Synthesis and binding affinity of rationally designed artificial ditopic nucleobase receptors are reported. The ditopic receptors were designed to recognize thymine-thymine dinucleotides by their two hydrogen-bonding moieties, which are connected to conformationally well-defined linkages such as ferrocene and biphenylene. The ditopic receptors exhibited a remarkably strong binding affinity for lipophilic TpT analogue in CDCl(3)/DMSO-d(6) (85:15, v/v). The binding affinity of the ditopic receptors for the dinucleotide was so high that even native TpT was extracted by them into CDCl(3). Detailed comparisons for the recognition abilities of the ditopic receptors were also conducted. 相似文献
67.
Kiyoshi Tanaka Hideki Takahashi Kozo Takimoto Masahiko Sugita Keiryo Mitsuhashi 《Journal of heterocyclic chemistry》1992,29(4):771-777
Synthesis of pyrido[1′,2′:1,2]imidazo[4,5-b]quinoxalines by the facile cyclizations of 2,3-dichloroquinoxalines with 2-aminopyridines and of 2-amino-3-chloroquinoxalines with various substituted pyridines is described. 相似文献
68.
Addition reaction of two geometrical isomers of 1-chlorovinyl p-tolyl sulfoxides, derived from unsymmetrical ketones and chloromethyl p-tolyl sulfoxide, with lithium enolate of tert-butyl acetate gave single isomers of the adduct, respectively. Treatment of each diastereomer with i-PrMgCl resulted in the formation of magnesium carbenoids. Highly regiospecific 1,3-CH insertion reaction was found to take place from the magnesium carbenoids to afford cyclopropanes in high yields. Stereochemistry of the adducts, reaction mechanism, and origin of the regiospecificity are discussed. 相似文献
69.
Motokawa R Annaka M Nakahira T Koizumi S 《Colloids and surfaces. B, Biointerfaces》2004,38(3-4):213-219
By employing small-angle neutron scattering (SANS), we investigated the microstructures of, poly(N-isopropylacrylamide) (PNIPA)-block-poly(ethylene glycol) (PEG) (NE) in deuterated water D2O, as related to macroscopic behaviors of fluidity, turbidity and synerisis. SANS revealed following results: (i) microphase separation occurs at around above 17 °C in a temperature range of transparent sol below 30 °C. In the microdomain appeared in the transparent sol state, both block chains of PNIPA and PEG are swollen by water; (ii) for the NE solution of polymer concentration Wp > 3.5% (w/v), corresponding to opaque gel above 30 °C, a percolated structure, i.e., network-like domain is formed by NE as a result of macrophase separation due to dehydration of the PNIPA chains. As the temperature increases toward 40 °C, the network domain is squeezed along a direction parallel to the NE interface, which leads to increase of the interfacial thickness given by swollen PEG chains and to the macroscopic synerisis behavior. 相似文献
70.