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61.
高效阳离子交换法分离纯化蛋清中的溶菌酶 总被引:3,自引:0,他引:3
建立了用高效阳离子交换分离纯化蛋清中溶菌酶的新方法 ,讨论了纯化的工艺条件。蛋清样品匀浆后 ,用氯化钠初步纯化 ,然后用弱阳离子交换柱XIDACE WCX分离。结果表明 ,被纯化的溶菌酶和杂蛋白得到很好分离。经活性检测 ,溶菌酶过柱后的活性回收率为 10 7% ,蛋白的比活为 15 4 6 7U/mg ,纯化倍数提高了 5 6倍。用尺寸排阻 (SEC)鉴定 ,得到的溶菌酶呈均一性。该法较传统软基质低压离子交换分离速度快 ,纯化效率高。 相似文献
62.
Ângela F. S. S. Mendonça Dina T. R. Formigo Isabel M. S. Lampreia 《Journal of solution chemistry》2002,31(8):653-670
Solubilities of triethylamine in aqueous tetraethylammonium chloride solutions were measured at 20, 25, and 35°C. The molalities in Et4NCl of the aqueous solvents ranged from 0.03 to 1 mol-kg–1. The data were evaluated from density measurements using a vibrating-tube densimeter. At each temperature, least-squares method was used to fit experimental density data points to double polynomial equations of various degrees. Triethylamine molalities of the saturated aqueous phases were estimated by extrapolation from those equations. Experimental data were interpreted in terms of hydrophobic and electrostatic perturbed domains in the hydration shells of the noneleceory and of the cation of the salt, as a function of temperature and salt concentration. The conclusions obtained are consistent with previous volumetric studies. 相似文献
63.
Egorochkin A. N. Voronkov M. G. Skobeleva S. E. Zderenova O. V. 《Russian Chemical Bulletin》2001,50(1):35-42
The first vertical ionization potentials (I) of phosphorus compounds P(Xi)3, OP(Xi)3, SP(Xi)3, (4-XC6H4)3P, and PCX are related to the inductive, resonance, and polarizability parameters of inorganic, organic, and organometallic substituents X by dependences of the type I = I
H + aI + bR
+ + c, where I
H is the I value for X = H. The I values are also affected by hyperconjugation. The ratio of the contributions of the resonance (bR
+) and polarizability (c) effects to the I value is determined by the degree of delocalization of the unpaired electron and the positive charge in the radical cations formed upon ionization of neutral molecules. The R
+ resonance parameters of organosilicon, organogermanium, and organotin substituents bound to the P
·+ radical cation center were calculated for the first time. 相似文献
64.
Sumio Kato Masataka Ogasawara Mikio Sugai Shinichi Nakata 《Catalysis Surveys from Asia》2004,8(1):27-34
Studies on the role of oxygen vacancy in structural change of nonstoichiometric perovskites and a property of oxygen-deficient perovskite-related K2NiF4 compounds are reviewed.The structural changes on which the authors focused are cation ordering and lattice distortion. The relationship between the distortion and oxygen vacancy was investigated by comparing the structures of Sr2(Sr1-xMx)TaO6-d (M = Ca2+ and Nd3+) solid solutions. It was found that distortion of a perovskite-type lattice decreased with an increasing amount of oxygen vacancies. In order to investigate the relationship between the cation ordering on octahedral sites and oxygen vacancy, structures of stoichiometric Sr2-xLaxCo1-yTa1+yO6 and oxygen-deficient Sr2-xLaxMg1-yTa1+yO6-d solid solutions were compared. The authors' work reveals that the cation ordering affects the amount of oxygen vacancies in addition to cation charge and size. 相似文献
65.
Specific sorption sites for nitrogen, N2, in NaLSX and LiLSX zeolites were investigated using a DRIFT spectroscopic method. Sorption of molecular hydrogen, H2, by NaLSX or LiLSX zeolite at 77 K with DRIFT control of perturbation of sorbed molecules allowed to discriminate two or three different types of specific sorption sites in the respective zeolites. Their H–H stretching frequencies are 4077 and 4081 cm–1 for NaLSX, and 4061, 4084 and 4129 cm–1 for LiLSX. With reference to an independent investigation by methods of both sorption thermodynamics and molecular modeling for N2 sorption on LiLSX, the first two of the corresponding bands were ascribed to H2 sorption on lithium cations, Li+, localized in supercages of the faujasite, FAU, zeolite framework at sites SIII and SIII, while the latter band most likely belongs to H2 sorption on Li+ cations at sites SII, and on hydroxyl groups, OH. Sorption of N2 by Li+ cations at sites SIII and SIII is the strongest, resulting in a decrease of intensity of the corresponding DRIFT bands that stem from subsequent H2 sorption. Nitrogen sorption by Li+ cations at sites SII is much weaker. Sorption of N2 on Na+ cations at sites SIII in NaLSX zeolite is also stronger than by Na+ cations at sites SII. 相似文献
66.
Ryo HorikoshiTomoyuki Mochida Hiroshi Moriyama 《Journal of solid state chemistry》2002,164(2):320-325
A series of ionic 4-(4′-pyridylthio)-1-methylpyridinium salts with different counteranions (1, I−; 2, BF−4; 3, PF−6; and 4, OTf−, where OTf=trifluoromethanesulfonate) have been prepared. Structural analysis reveals that the cation exhibits a variety of stacking structures dependent on the anion. Compound 1 crystallizes in space group P21/n (#14), with a=10.764(3) Å, b=9.601(5) Å, c=13.105(3) Å, β=108.35(2), V=1285.4(8) Å3, and Z=4. In this compound, each cation moiety is stacked in a helical arrangement along the c-axis. Compound 2, which is isomorphous to 1, has space group P21/n (#14), with a=11.647(2) Å, b=9.203(3) Å, c=13.232(2) Å, β=108.42(2), V=1345.6(5) Å3, and Z=4. Compound 3 crystallizes in space group P21/n (#14), with a=8.06(1) Å, b=17.43(1) Å, c=10.30(1) Å, β=103.0(1), V=1410(3) Å3, and Z=4. In this salt, the cation molecules assume a head-to-tail stacking arrangement, forming a polar pseudo 1-D chain. Compound 4 crystallizes in space group Pb? (#2), with a=7.585(4) Å, b=15.443(7) Å, c=6.775(4) Å, α=99.33(4), β=108.35(2)o, γ=98.37(4), V=756.6(7) Å3, and Z=2. The structure of 4 consists of a columnar stacking of pyridine moieties, with the cation moieties surrounded by the counteranions. Calculations show that the 4-(4′-pyridylthio)-1-methylpyridinium cation may be a good building block for second harmonic generation (SHG) materials, even though salts 1-4 crystallized in centrosymmetric structures and were SHG inactive. 相似文献
67.
Pentafluorophenyliodine(III) Compounds. 2. Fluorine-Aryl Substitution Reactions on Iodinetrifluoride: Synthesis of Pentafluorophenyliodinedifluoride C6F5IF2 and Bis(pentafluorophenyl)iodonium Pentafluorophenylfluoroborates[(C6F5)2I]+[(C6F5)nBF4?n]? Mono- and disubstitution can be achieved in the fluorine-aryl substitution reaction on the low-temperature phase IF3 in CH2Cl2 at ?78°C depending on the aryl transfer reagent. With B(C6F5)3 [(C6F5)2I]+ [(C6F5)nBF4?n]? (68% yield) and with Cd(C6F5)2 C6F5IF2 (97% yield) is obtained whereas with C6F5SiMe3 no fluorine-aryl substitution takes place on IF3 even under basic conditions (EtCN or F? addition). At ?78°C in EtCN solution IF3 does not disproportionate but attacks the solvent under formation of HF. 相似文献
68.
Xe(OTeF5)2 reacts with Sb(OTeF5)3 under the formation of [Xe2(OTeF5)3]+[Sb(OTeF5)6]-. From SO2ClF solution a yellow solvate [F5TeOXe]+·SO2ClF· [Sb(OTeF5)6]- is formed with the crystal data: a = 1028.1(1), b = 1040.9(1), c = 1780.2(3) pm, α = 98.07(1), β = 97.68(1), γ = 105.82(1)°, space group . The O-Xe···O fragment is essentially linear (176.1(2)°), and the two Xe-O distances are quite different 197.1(4) and 242.6(4) pm. 相似文献
69.
用混合床离子色谱柱同时测定阴阳离子 总被引:3,自引:0,他引:3
将阴离子交换树脂和阳离子交换换树脂混合后填充在一根色谱柱中,即所谓阴阳离子混合床柱。研究了阴阳离子在此混合柱上的保留行为并探讨了其保留机理。 相似文献
70.
Young Gun Ko Ung Su Choi Yong Sung Park Je Wan Woo 《Journal of polymer science. Part A, Polymer chemistry》2004,42(8):2010-2018
The role of hydrogen bonding in the chemistry of transition‐metal complexes remains a topic of intense scientific and technological interest. Poly(acrylo‐amidino diethylenediamine) was synthesized to study the effects of hydrogen bonding on complexes at different pHs. The polymer was synthesized through the coupling of diethylene triamine with polyacrylonitrile fiber in the presence of AlCl3 · 6H2O addition. The adsorption capacity of this polymer was 11.4 mequiv/g. The ions used for the adsorption test were CrO, PO, Cu2+, Ni2+, Fe2+, and Ag+. All experiments were confirmed with Fourier transform infrared. In the study of anion adsorption, at low pHs, only ionic bonds existed, whereas at high pHs, no bonds existed. However, in the middle pH region, both ionic bonds and hydrogen bonds formed between poly(acrylo‐amidino diethylenediamine) and the chromate ion or phosphate ion. When poly(acrylo‐amidino diethylenediamine) and metal ions (Cu2+, Ni2+, Fe2+, and Ag+) formed complexes, a hydrogen‐bonding effect was not observed with Fourier transform infrared. The quantity of metal ions adsorbed onto poly(acrylo‐amidino diethylenediamine) followed the order Ag+ > Cu2+ > Fe2+ > Ni2+. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2010–2018, 2004 相似文献