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831.
832.
The reactions of 2,2'-dimethoxy-1,1'-binaphthyl-3,3'-bis(4-vinylpyridine)(L) with AgNO3 or AgClO4 at 70 degrees C gave rise to two novel luminescent homochiral lamellar coordination polymers, AgL2X (X = NO3- for 1 or ClO4- for 2), which are built from linking helical chains by Ag(I) atoms as hinges. 相似文献
833.
Dallas B. Warren David K. Chalmers Keith Hutchison Wenbin Dang Colin W. Pouton 《Colloids and surfaces. A, Physicochemical and engineering aspects》2006,280(1-3):182-193
Bile salts are surfactants in bile that facilitate digestion, adsorption and excretion of various compounds. They have planar hydrophobic and hydrophilic faces and therefore exhibit some unusual properties; including the shape and size of the micelles that they form. Molecular dynamics simulations of the spontaneous aggregation of six bile salts (cholate (CHD), glycocholate (GCH), taurocholate (TCH), glycochenodeoxycholate (GCD), glycodeoxycholate (GDX) and glycolithocholate (GLC)) were performed in an aqueous phase to gain insight into their micellar structure. The aggregates that formed spontaneously from a random distribution of molecules ranged in size from 8 to 17 molecules. The structures are highly dynamic in nature and are on average oblate, but can vary from oblate, to spherical or prolate. Intermolecular hydrogen bonding within the micelles was found to be an important factor in determining the micelle size, structure and dynamics. The molecular arrangement within the micelles maximises the hydration of the hydrophilic chains and some favourable orientations for adjacent molecules were acquired. The dynamics of the micelles were investigated using the hydrogen-bond lifetime autocorrelation function correlation time, which exhibited a relationship with the degree of hydroxylation. Comparison of the proposed model to the three literature models showed some features of the disk shaped models of Cary and Small [M.C. Cary, D.M. Small, Arch. Intern. Med. 130 (1972) 506–527] and Kawamura et al. [H. Kawamura, Y. Murata, T. Yamaguchi, H. Igimi, M. Tanaka, G. Sugihara, J.P. Kratohvil, J. Phys. Chem. 93 (1989) 3321–3326], whereas the third, inverted helix model of Giglio et al. [E. Giglio, S. Loreti, N.V. Pavel, J. Phys. Chem. 92 (1988) 2858–2862] can be discounted. The proposed model is better than the existing models, which assumed a rigid and structured molecular arrangement. 相似文献
834.
NaCl、KCl在蔗糖水溶液中的粘度 总被引:2,自引:0,他引:2
报导了在298.15及308.15K下,NaCl、KCl在含有蔗糖5,10,15,20,25%(质量分数w)的水溶液中的密度及粘度数据.计算了在无限稀释条件下,NaCl和KCl在该体系中的粘度B系数及偏摩尔体积.结果发现:两种电解质的B系数随蔗糖含量的增加及温度的升高而增大且对蔗糖水溶液的结构起破坏作用.讨论了该三元体系内部溶质-溶质、溶质-溶剂间的相互作用,同时应用流动过渡状态理论计算了两种电解质在各组成下蔗糖水溶液中的流动活化参数 相似文献
835.
A new chiral bridging ligand, 2,2'-pentaethylene glycol-1,1'-binaphthyl-6,6'-bis(phosphonic acid), was synthesized in 40.7% overall yield in five steps and used to generate single crystals of the first porous lanthanide phosphonates with chiral crown ether pillars. Single-crystal and powder X-ray crystallography established that these chiral crown ether decorated lamellar solids retain their framework structures after the removal of their included guest molecules and serve as structural models for porous solids that are exploitable for bulk chiral separations. 相似文献
836.
A new rigid angular bridging ligand, 7-oxa-dibenzofluorene-3,11-dicarboxylic acid (H(2)L), was synthesized by cyanation of known rac-6,6'-dibromo-1,1'-bi-2-naphthol followed by ring closure and hydrolysis with concentrated sulfuric acid and used for the self-assembly of nanoscopic molecular rectangle [Cu(4)(L)(4)(Py)(8)].2DMF.10H(2)O, 1, and 1-D coordination polymer [Co(2)(L)(2)(Py)(4)].2DMF.2H(2)O, 2. Both 1 and 2 contain open channels occupied by DMF and water guest molecules. Crystal data for 1:[?] triclinic, space group P(-)1, a = 8.869(2) A, b = 16.437(3) A, c = 21.586(4) A, alpha = 78.18(3), beta = 79.19(3), gamma = 83.66(3), U = 3017.0(11) A(3), and Z = 1. Crystal data for 2: triclinic, space group P(-)1, a = 8.254(2) A, b = 12.154(2) A, c = 15.348(3) A, alpha = 95.34(3), beta = 93.38(3), gamma = 94.37(3), U = 1525.1(5) A(3), and Z = 1. 相似文献
837.
β-环糊精对显色反应作用的研究 Ⅰ.铬天青S和埃铬菁R体系 总被引:1,自引:0,他引:1
本文研究了β-环糊精(β-CD)及阳离子表面活性剂-β-CD 对 Al(Ⅲ)、Ga(Ⅲ)、In(Ⅲ)的铬天青 S 和埃铬菁 R 体系的作用及有关机理。结果表明,β-CD 对这些体系均无增敏作用、加入 CTMAB 或 CPB 后,产生不同程度的增敏作用,并有如下顺序:In(Ⅲ)-CAS(ECR)>Ga(Ⅲ)-CAS(ECR)>Al(Ⅲ)-CAS(ECR).其原因在于,阳离子表面活性剂的憎水基进入β-CD内腔,而另一端与显色螯合离子缔合,形成包合-缔合“桥式”结构,其极性比单独β-CD 增大,从而产生协同增敏作用。金属离子 In(Ⅲ)的离子半径最大,外层电子为18电子型,与显色剂形成的螫合离子极性也最大,与带异电的阳离子表面活性剂-β-CD 相互极化作用最强,故增敏作用最强。而 Al(Ⅲ)的离子半径最小,电子构型属惰气型,与阳离子表面活性剂-β-CD缔合作用最弱,故增敏作用也最低。 相似文献
838.
A homochiral triple helix was self-assembled from an axially chiral bipyridine and a linear metal-connecting point, which further assembles into a 2D network via infinite pi...pi stacking interactions and acts as a host for the inclusion of guest molecules. 相似文献
839.
β—环糊精及其衍生物对萘胺的荧光增强效应及机理 总被引:7,自引:0,他引:7
研究了β-环糊精及其衍生物丙基-β-环糊精、叔胺-β-环糊精对萘胺荧光强度的影响,发现HP-β-CD、TA-β-CD对萘胺的荧光增强作用比β-CD大。 相似文献
840.
Treatments of lanthanide nitrate or perchlorate and C2-symmetric 2,2'-hydroxy-1,1'-binaphthalene-6,6'-dicarboxylic acid (6,6'-H2BDA) led to diastereoselective self-assembly of nanoscale, porous molecular adamantanoids [Ln4(BDA)6(H2O)12]*12DMF (Ln = Gd, La, 1a,b). These adamantanoid clusters possess perfect T symmetry as a result of the C2-symmetric nature of BDA bridging ligands and C3-symmetric nature of lanthanide ions. Face-to-face intercluster hydrogen bonds formed between 2,2'-dihydroxyl groups of BDA ligands and carboxylate oxygen atoms direct the assembly of 3D polycages based on chiral molecular adamantanoid building blocks which possess two different types of open channels. 相似文献