全文获取类型
收费全文 | 13343篇 |
免费 | 558篇 |
国内免费 | 87篇 |
专业分类
化学 | 8774篇 |
晶体学 | 112篇 |
力学 | 324篇 |
综合类 | 1篇 |
数学 | 2470篇 |
物理学 | 2307篇 |
出版年
2023年 | 97篇 |
2022年 | 70篇 |
2021年 | 227篇 |
2020年 | 259篇 |
2019年 | 292篇 |
2018年 | 211篇 |
2017年 | 227篇 |
2016年 | 520篇 |
2015年 | 426篇 |
2014年 | 439篇 |
2013年 | 819篇 |
2012年 | 755篇 |
2011年 | 865篇 |
2010年 | 591篇 |
2009年 | 502篇 |
2008年 | 679篇 |
2007年 | 703篇 |
2006年 | 564篇 |
2005年 | 638篇 |
2004年 | 548篇 |
2003年 | 426篇 |
2002年 | 365篇 |
2001年 | 186篇 |
2000年 | 176篇 |
1999年 | 120篇 |
1998年 | 130篇 |
1997年 | 127篇 |
1996年 | 121篇 |
1995年 | 108篇 |
1994年 | 100篇 |
1993年 | 113篇 |
1992年 | 96篇 |
1991年 | 98篇 |
1990年 | 96篇 |
1989年 | 88篇 |
1988年 | 73篇 |
1987年 | 75篇 |
1986年 | 85篇 |
1985年 | 133篇 |
1984年 | 133篇 |
1983年 | 106篇 |
1982年 | 92篇 |
1981年 | 94篇 |
1980年 | 84篇 |
1979年 | 86篇 |
1978年 | 97篇 |
1977年 | 64篇 |
1976年 | 69篇 |
1975年 | 72篇 |
1974年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Dominik Vítek Prof. Aleš Růžička Lise Vermeersch Dr. Libor Dostál Dr. Jan Turek Prof. Roman Jambor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(70):e202202639
Reactivity studies of the GeII→B complex L(Cl)Ge⋅BH3 ( 1 ; L=2-Et2NCH2-4,6-tBu2-C6H2) were performed to determine the effect on the GeII→B donation. N-coordinated compounds L(OtBu)Ge⋅BH3 ( 2 ) and [LGe⋅BH3]2 ( 3 ) were prepared. The possible tuning of the GeII→B interaction was proved experimentally, yielding compounds 1-PPh2-8-(LGe)-C10H6 ( 4 ) and L(Cl)Ge⋅GaCl3 ( 5 ) without a GeII→B interaction. In 5 , an unprecedented GeII→Ga coordination was revealed. The experimental results were complemented by a theoretical study focusing on the bonding in 1 − 5 . The different strength of the GeII→E (E=B, Ga) donation was evaluated by using energy decomposition analysis. The basicity of different L(X)Ge groups through proton affinity is also assessed. 相似文献
2.
Nonlinear Dynamics - In this article, the authors simulate and study dark and bright soliton solutions of 1D and 2D regularized long wave (RLW) models. The RLW model occurred in various fields such... 相似文献
3.
4.
5.
6.
Lubomír Havlk Jan Fbry Margarida Henriques Michal Duek 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(7):623-630
The title structures of KScS2 (potassium scandium sulfide), RbScS2 (rubidium scandium sulfide) and KLnS2 [Ln = Nd (potassium neodymium sufide), Sm (potassium samarium sulfide), Tb (potassium terbium sulfide), Dy (potassium dysprosium sulfide), Ho (potassium holmium sulfide), Er (potassium erbium sulfide), Tm (potassium thulium sulfide) and Yb (potassium ytterbium sulfide)] are either newly determined (KScS2, RbScS2 and KTbS2) or redetermined. All of them belong to the α‐NaFeO2 structure type in agreement with the ratio of the ionic radii r3+/r+. KScS2, the member of this structural family with the smallest trivalent cation, is an extreme representative of these structures with rare earth trivalent cations. The title structures are compared with isostructural alkali rare earth sulfides in plots showing the dependence of several relevant parameters on the trivalent cation crystal radius; the parameters thus compared are c, a and c/a, the thicknesses of the S—S layers which contain the respective constituent cations, the sulfur fractional coordinates z(S2−) and the bond‐valence sums. 相似文献
7.
8.
Nováková Kateřina Hrdlička Vojtěch Navrátil Tomáš Vyskočil Vlastimil Barek Jiří 《Monatshefte für Chemie / Chemical Monthly》2015,146(5):761-769
Monatshefte für Chemie - Chemical Monthly - The voltammetric behavior of 5-nitroindazole was investigated at polished (p-AgSAE) and at mercury meniscus-modified (m-AgSAE) silver solid amalgam... 相似文献
9.
Formation of porous polymer morphology by microsyneresis during divinylbenzene polymerization 下载免费PDF全文
Libuše Hanková Ladislav Holub Karel Jeřábek 《Journal of Polymer Science.Polymer Physics》2015,53(11):774-781
This article describes the investigation of the importance of various reaction conditions on microsyneretic pore formation during polymerization of divinylbenzene (DVB) under so‐called “solvothermal” conditions. To induce microsyneretic pore formation, the most important parameter is an unusually high dilution of monomers with a “good” porogen solvating the polymer chains. High dilution and solvation of the growing poly(DVB) chains promote the prolongation of the polymer chains rather than their interconnection by crosslinking. Consequently, when the polymer gel density reaches the point where syneresis starts, the polymer network is geometrically too extensive to be broken up into precipitating entities and, instead, porogen droplets are formed within the continuous polymer gel. The pore geometry created by microsyneresis offers high surface area in wide mesopores and hence, high capacity for supporting functional groups or reactions with much better accessibility than narrow pores between polymer microspheres produced by macrosyneresis in conventional styrenic polymer supports. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 774–781 相似文献
10.