全文获取类型
收费全文 | 43814篇 |
免费 | 1656篇 |
国内免费 | 257篇 |
专业分类
化学 | 29506篇 |
晶体学 | 329篇 |
力学 | 835篇 |
综合类 | 4篇 |
数学 | 7057篇 |
物理学 | 7996篇 |
出版年
2023年 | 262篇 |
2022年 | 554篇 |
2021年 | 739篇 |
2020年 | 767篇 |
2019年 | 841篇 |
2018年 | 676篇 |
2017年 | 682篇 |
2016年 | 1394篇 |
2015年 | 1230篇 |
2014年 | 1384篇 |
2013年 | 2427篇 |
2012年 | 2644篇 |
2011年 | 3017篇 |
2010年 | 1838篇 |
2009年 | 1715篇 |
2008年 | 2529篇 |
2007年 | 2437篇 |
2006年 | 2267篇 |
2005年 | 2157篇 |
2004年 | 1786篇 |
2003年 | 1494篇 |
2002年 | 1315篇 |
2001年 | 811篇 |
2000年 | 729篇 |
1999年 | 636篇 |
1998年 | 520篇 |
1997年 | 511篇 |
1996年 | 603篇 |
1995年 | 487篇 |
1994年 | 472篇 |
1993年 | 452篇 |
1992年 | 430篇 |
1991年 | 362篇 |
1990年 | 355篇 |
1989年 | 313篇 |
1988年 | 280篇 |
1987年 | 273篇 |
1986年 | 253篇 |
1985年 | 329篇 |
1984年 | 332篇 |
1983年 | 242篇 |
1982年 | 287篇 |
1981年 | 267篇 |
1980年 | 246篇 |
1979年 | 227篇 |
1978年 | 230篇 |
1977年 | 191篇 |
1976年 | 168篇 |
1975年 | 168篇 |
1973年 | 142篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Martin Kellert Jan-Simon Jeshua Friedrichs Nadine Anke Ullrich Alexander Feinhals Jonas Tepper Peter Lnnecke Evamarie Hey-Hawkins 《Molecules (Basel, Switzerland)》2021,26(7)
The development of novel, tumor-selective and boron-rich compounds as potential agents for use in boron neutron capture therapy (BNCT) represents a very important field in cancer treatment by radiation therapy. Here, we report the design and synthesis of two promising compounds that combine meta-carborane, a water-soluble monosaccharide and a linking unit, namely glycine or ethylenediamine, for facile coupling with various tumor-selective biomolecules bearing a free amino or carboxylic acid group. In this work, coupling experiments with two selected biomolecules, a coumarin derivative and folic acid, were included. The task of every component in this approach was carefully chosen: the carborane moiety supplies ten boron atoms, which is a tenfold increase in boron content compared to the l-boronophenylalanine (l-BPA) presently used in BNCT; the sugar moiety compensates for the hydrophobic character of the carborane; the linking unit, depending on the chosen biomolecule, acts as the connection between the tumor-selective component and the boron-rich moiety; and the respective tumor-selective biomolecule provides the necessary selectivity. This approach makes it possible to develop a modular and feasible strategy for the synthesis of readily obtainable boron-rich agents with optimized properties for potential applications in BNCT. 相似文献
13.
14.
Functional Carbazole Liquid‐Crystal Block Codendrimers with Optical and Electronic Properties 下载免费PDF全文
Ismael Gracia Beatriz Feringán Prof. José Luis Serrano Dr. Roberto Termine Dr. Attilio Golemme Dr. Ana Omenat Prof. Joaquín Barberá 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(3):1359-1369
The synthesis and characterisation of a family of block codendrimers consisting of highly versatile mesogenic and carbazole‐containing 2,2‐bis(hydroxymethyl)propionic acid (bis‐MPA) dendrons are reported. The liquid‐crystal behaviour was investigated by means of differential scanning calorimetry, polarised‐light optical microscopy and X‐ray diffraction. Depending on the chemical structure of the constituent dendrons, the codendrimers show lamellar or columnar mesophases. On the basis of the experimental results, models both at the molecular level and in the mesophase are proposed. The physical properties of the block codendrimers derived from the presence of the carbazole moiety in their structure were investigated: photoluminescence in solution and in the mesophase, electrochemical behaviour and hole transport. Electrodeposition of carbazole dendrons afforded a globular supramolecular conformation in which the mesogenic molecular side plays a key role. 相似文献
15.
16.
Martin Ulirsch 《Mathematische Zeitschrift》2015,280(1-2):195-210
17.
18.
19.
20.