全文获取类型
收费全文 | 245篇 |
免费 | 15篇 |
国内免费 | 3篇 |
专业分类
化学 | 195篇 |
晶体学 | 1篇 |
力学 | 1篇 |
数学 | 21篇 |
物理学 | 45篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 7篇 |
2014年 | 11篇 |
2013年 | 15篇 |
2012年 | 22篇 |
2011年 | 22篇 |
2010年 | 9篇 |
2009年 | 16篇 |
2008年 | 14篇 |
2007年 | 14篇 |
2006年 | 16篇 |
2005年 | 9篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1975年 | 1篇 |
1971年 | 1篇 |
1955年 | 1篇 |
1941年 | 1篇 |
1936年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有263条查询结果,搜索用时 15 毫秒
151.
Amornrat Lertworasirikul Nu‐orn Choothong Hiroaki Yoshida Michiya Matsusaki Toshiyuki Kida Apirat Laobuthee Mitsuru Akashi 《Journal of polymer science. Part A, Polymer chemistry》2012,50(23):4823-4828
The thermosensitivity of biodegradable and non‐toxic amphiphilic polymer derived from a naturally occurring polypeptide and a derivative of amino acid was first reported. The amphiphilic polymer consisted of poly(γ‐glutamic acid) (γ‐PGA) as a hydrophilic backbone, and L ‐phenylalanine ethyl ester (L ‐PAE) as a hydrophobic branch. Poly(γ‐glutamic acid)‐graft‐L ‐phenylalanine (γ‐PGA‐graft‐L ‐PAE) with grafting degrees of 7–49% were prepared by varying the content of a water‐soluble carbodiimide (WSC). γ‐PGA‐graft‐L ‐PAE with a grafting degree of 49% exhibited thermoresponsive phase transition behavior in an aqueous solution at around 80°C. The copolymers with grafting degrees in the range of 30–49% showed thermoresponsive properties in NaCl solution. A clouding temperature (Tcloud) could be adjusted by changing the polymer concentration and/or NaCl concentration. The thermoresponsive behavior was reversible. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
152.
Given a finite map germ f : (X, 0) → (Y, 0) between complex analytic reduced space curves, we look at invariants which control the topological triviality and the Whitney equisingularity in families of this type of map germs. In the case that (Y, 0) is smooth, the main invariant is the Milnor number of a function on a curve. We deduce some applications to the equisingularity of families of finitely determined map germs ${f : (\mathbb{C}^2, 0) \to (\mathbb{C}^2, 0)}$ and ${f : (\mathbb{C}^2, 0) \to (\mathbb{C}^3, 0)}$ . 相似文献
153.
We consider smooth finitely C 0- ${\mathcal{K}}$ -determined map germs ${f : (\mathbb{R}^n, 0) \to (\mathbb{R}^p, 0)}$ and we look at the classification under C 0- ${\mathcal{K}}$ -equivalence. The main tool is the homotopy type of the link, which is obtained by intersecting the image of f with a small enough sphere centered at the origin. When f ?1(0) = {0}, the link is a smooth map between spheres and f is C 0- ${\mathcal{K}}$ -equivalent to the cone of its link. When f ?1(0) ≠ {0}, we consider a link diagram, which contains some extra information, but again f is C 0- ${\mathcal{K}}$ -equivalent to the generalized cone. As a consequence, we deduce some known results due to Nishimura (for n = p) or the first named author (for n < p). We also prove some new results of the same nature. 相似文献
154.
Synthetic polymeric flocculants are used extensively for wastewater remediation, soil stabilization, and reduction in water
leakage from unlined canals. Sources of highly active, inexpensive, renewable flocculants are needed to replace synthetic
flocculants. High kaolin flocculant activity was documented for bovine blood (BB) and blood plasma with several anticoagulant
treatments. BB serum also had high flocculant activity. To address the hypothesis that some blood proteins have strong flocculating
activity, the BB proteins were separated by SEC. Then, the major proteins of the flocculant-active fractions were separated
by SDS-PAGE. Identity of the major protein components was determined by tryptic digestion and peptide analysis by MALDI TOF
MS. The sequence of selected peptides was confirmed using TOF/TOF-MS/MS fragmentation. Hemoglobin dimer (subunits α and β)
was identified as the major protein component of the active fraction in BB; its high flocculation activity was confirmed by
testing a commercial sample of hemoglobin. In the same manner, three proteins from blood plasma (fibrinogen, γ-globulin, α-2-macroglobulin)
were found to be highly active flocculants, but bovine serum albumin, α-globulin, and β-globulin were not flocculants. On
a mass basis, hemoglobin, γ-globulin, α-2-macroglobulin were as effective as anionic polyacrylamide (PAM), a widely used synthetic
flocculant. The blood proteins acted faster than PAM, and unlike PAM, the blood proteins flocculants did not require calcium
salts for their activity. 相似文献
155.
We give a stereological version of the Gauss–Bonnet formula in order to compute the Euler characteristic of a domain with boundary in a smooth orientable surface in 3, by looking at contacts with a 'sweeping' plane. 相似文献
156.
John Hurtado Nelson Nuñez-Dallos Santiago Movilla Gian Pietro Miscione Brian C. Peoples René Rojas 《Journal of Coordination Chemistry》2017,70(5):803-818
Reaction of benzotriazole with 2,6-bis(bromomethyl)pyridine and 2,6-pyridinedicarbonyl dichloride yields the tridentate ligands 2,6-bis(benzotriazol-1-ylmethyl)pyridine (1) and 2,6-bis(benzotriazol-1-ylcarbonyl) pyridine (2). The molecular structures of the ligands were determined by single-crystal X-ray diffraction. These ligands react with CrCl3(THF)3 in THF to form neutral complexes, [CrCl3{2,6-bis(benzotriazolyl)pyridine-N,N,N}] (3, 4), which are isolated in high yields as air stable green solids and characterized by mass spectra (ESI), FTIR spectroscopy, UV–Visible, thermogravimetric analysis (TGA), and magnetic measurements. After reaction with methylaluminoxane (MAO), the chromium(III) complexes are active in the polymerization of ethylene showing a bimodal molecular weight distribution. A DFT computational investigation of the polymerization reaction mechanism shows that the most likely reaction pathway originates from the mer configuration when the spacer is CH2 (complex 3) and from the fac configuration when the spacer is CO (complex 4). 相似文献
157.
[{mu-(Pyridazine-N(1):N(2))}Fe(2)(mu-CO)(CO)(6)](1) reacts with aryllithium reagents, ArLi (Ar = C(6)H(5), m-CH(3)C(6)H(4)) followed by treatment with Me(3)SiCl to give the novel pyridazine-coordinated diiron bridging siloxycarbene complexes [(C(4)H(4)N(2))Fe(2){mu-C(OSiMe(3))Ar}(CO)(6)](2, Ar = C(6)H(5); 3, Ar =m-CH(3)C(6)H(4)). Complex 2 reacts with HBF(4).Et(2)O at low temperature to yield a cationic bridging carbyne complex [(C(4)H(4)N(2))Fe(2)(mu-CC(6)H(5))(CO)(6)]BF(4)(4). Cationic 4 reacts with NaBH(4) in THF at low temperature to afford the diiron bridging arylcarbene complex [(C(4)H(4)N(2))Fe(2){mu-C(H)C(6)H(5)}(CO)(6)](5). Unexpectedly, the reaction of 4 with NaSCH(3) under similar conditions gave the bridging arylcarbene complex 5 and a carbonyl-coordinated diiron bridging carbene complex [Fe(2){mu-C(SCH(3))C(6)H(5)}(CO)(7)](6), while the reaction of NaSC(6)H(4)CH(3)-p with 4 affords the expected bridging arylthiocarbene complex [(C(4)H(4)N(2))Fe(2){mu-C(SC(6)H(4)CH(3)-p)C(6)H(5)}(CO)(6)](7), which can be converted into a novel diiron bridging carbyne complex with a thiolato-bridged ligand, [Fe(2)(mu-CC(6)H(5))(mu-SC(6)H(4)CH(3)-p)(CO)(6)](8). Cationic can also react with the carbonylmetal anionic compound Na(2)[Fe(CO)(4)] to yield complex 5, while the reactions of 4 with carbonylmetal anionic compounds Na[M(CO)(5)(CN)](M = Cr, Mo, W) produce the diiron bridging aryl(pentacarbonylcyanometal)carbene complexes [(C(4)H(4)N(2))Fe(2)-{mu-C(C(6)H(5))NCM(CO)(5)}(CO)(6)](9, M = Cr; 10, M = Mo; 11, M = W). The structures of complexes 2, 5, 6, 8, and 9 have been established by X-ray diffraction studies. 相似文献
158.
159.
160.
Xiaofeng Luo Bedangadas Mohanty Hans Georg Ritter Nu Xu 《Physics of Atomic Nuclei》2012,75(6):676-678
Higher moments of event-by-event net-proton multiplicity distributions have been applied to search for the QCD critical point. Model results are used to provide a baseline for this search. The measured moment products, ??? 2 and S?? of net-proton distributions, which are directly connected to the thermodynamical baryon number susceptibility ratio in Lattice QCD and Hadron Resonance Gas (HRG) model, are compared to the transport and thermal model results. We argue that a non-monotonic dependence of ??? 2 and S?? as a function of beam energy can be used to search for the QCD critical point. 相似文献