全文获取类型
收费全文 | 1169篇 |
免费 | 3篇 |
国内免费 | 2篇 |
专业分类
化学 | 769篇 |
晶体学 | 17篇 |
力学 | 7篇 |
数学 | 195篇 |
物理学 | 145篇 |
无线电 | 41篇 |
出版年
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 9篇 |
2016年 | 9篇 |
2015年 | 10篇 |
2013年 | 16篇 |
2012年 | 45篇 |
2011年 | 42篇 |
2010年 | 28篇 |
2009年 | 14篇 |
2008年 | 40篇 |
2007年 | 47篇 |
2006年 | 44篇 |
2005年 | 38篇 |
2004年 | 27篇 |
2003年 | 25篇 |
2002年 | 32篇 |
2001年 | 13篇 |
2000年 | 12篇 |
1999年 | 16篇 |
1998年 | 24篇 |
1997年 | 13篇 |
1996年 | 24篇 |
1995年 | 24篇 |
1994年 | 19篇 |
1993年 | 21篇 |
1992年 | 18篇 |
1991年 | 20篇 |
1990年 | 14篇 |
1989年 | 22篇 |
1988年 | 18篇 |
1987年 | 21篇 |
1986年 | 22篇 |
1985年 | 20篇 |
1984年 | 31篇 |
1983年 | 26篇 |
1982年 | 22篇 |
1981年 | 27篇 |
1980年 | 25篇 |
1979年 | 25篇 |
1978年 | 26篇 |
1977年 | 18篇 |
1976年 | 15篇 |
1974年 | 11篇 |
1973年 | 17篇 |
1972年 | 15篇 |
1971年 | 16篇 |
1969年 | 11篇 |
1967年 | 9篇 |
1966年 | 13篇 |
排序方式: 共有1174条查询结果,搜索用时 46 毫秒
101.
102.
103.
We construct a smash product operation on secondary homotopy groups yielding the structure of a lax symmetric monoidal functor.
Applications on cup-one products, Toda brackets and Whitehead products are considered.
The second author was partially supported by the Spanish Ministry of Education and Science under MEC-FEDER grants MTM2004-01865
and MTM2004-03629, the postdoctoral fellowship EX2004-0616, and a Juan de la Cierva research contract. 相似文献
104.
The small-angle x-ray scattering (SAXS) intensity of highly-oriented, low-density polyethylene (LDPE) with fixed draw ratio has been investigated during several heating and cooling cycles. Using a three-dimensional, monoclinic, paracrystalline superlattice to describe the superstructure of the sample, it has been possible to calculate the SAXS patterns completely. A very large irreversible variation of the superstructure during the first heating cycle, and a smaller reversible variation of the average size and distance of the crystallites during subsequent temperature cycles, could be obtained. These results can be explained using the thermodynamic theory of crystallization of polymer multicomponent systems of Kilian. 相似文献
105.
Peter Pirsch Carsten Reuter Jens Peter Wittenburg Mark B. Kulaczewski Hans-Joachim Stolberg 《The Journal of VLSI Signal Processing》2001,29(3):157-165
Architectural concepts are presented aimed at future multimedia processing schemes. Starting from an analysis of current and future multimedia applications, specific computational requirements are derived. It will be shown that multimedia applications benefit from an exhaustive and flexible exploitation of parallelism. Three architectural concepts—reconfigurable computing, simultaneous multithreading, and associative controlling—are presented, and their potential to increase further the performance on future multimedia applications is investigated. 相似文献
106.
107.
Since the permutation decoding algorithm is more efficient the smaller the size of the PD-set, it is important for the applications to find small PD-sets. A lower bound on the size of a PD-set is given by Gordon. There are examples for PD-sets, but up to now there is no method known to find PD-sets. The question arises whether the Gordon bound is sharp. To handle this problem we introduce the notion of antiblocking system and we show that there are examples where the Gordon bound is not sharp. 相似文献
108.
109.
Clarissa Müller Tim Ortmann Akram Abi Dave Hartig Stephan Scholl Hans-Joachim Jördening 《Applied biochemistry and biotechnology》2017,182(1):197-215
Immobilization methods and carriers were screened for immobilization of Euglena gracilis extract with laminaribiose phosphorylase activity. The extract was successfully immobilized on three different carriers via covalent linkage. Suitable immobilization carriers were Sepabeads EC-EP/S and ECR 8209M with epoxy groups and ECR 8309M with amino groups as functional units. Immobilization on Sepabeads EC-EP/S resulted in highest retained activity (65%). The immobilizates were characterized for pH, temperature, and buffer molarity preferences. The immobilized enzyme lost 48% of its activity when used seven times. Together with sucrose phosphorylase, laminaribiose phosphorylase was successfully applied for bienzymatic production of laminaribiose from sucrose and glucose with a final laminaribiose concentration of 14.3 ± 2.1 g/L (20% yield). 相似文献
110.
The binding of (partial) agonists in the binding pocket of biogenic amine receptors induces a conformational change from the
inactive to the active state of the receptors. There is only little knowledge about the binding pathways of ligands into binding
pocket on molecular level. So far, it was not possible with molecular dynamic simulations to observe the ligand binding and
receptor activation. Furthermore, there is nearly nothing known, in which state of ligand binding, the receptor gets activated.
The aim of this study was to get more detailed insight into the process of ligand binding and receptor activation. With the
recently developed LigPath algorithm, we scanned the potential energy surface of the binding process of dimeric histaprodifen, a partial agonist at
the histamine H1-receptor, into the guinea pig histamine H1-receptor, taking also into account the receptor activation. The calculations exhibited large conformational changes of Trp6.48 and Phe6.55 during ligand binding and receptor activation. Additionally, conformational changes were also observed for Phe6.52, Tyr6.51 and Phe6.44. Conformational changes of Trp6.48 and Phe6.52 are discussed in literature as rotamer toggle switch in context with receptor activation. Additionally, the calculations
indicate that the binding of dimeric histaprodifen, accompanied by receptor activation is energetically preferred. In general,
this study gives new, theoretical insights onto ligand binding and receptor activation on molecular level. 相似文献