首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   162篇
  免费   0篇
化学   88篇
力学   6篇
数学   22篇
物理学   46篇
  2023年   2篇
  2021年   1篇
  2020年   3篇
  2019年   3篇
  2015年   3篇
  2014年   3篇
  2013年   5篇
  2012年   4篇
  2011年   5篇
  2010年   4篇
  2009年   4篇
  2008年   6篇
  2007年   3篇
  2006年   4篇
  2005年   6篇
  2004年   6篇
  2003年   6篇
  2002年   4篇
  2001年   5篇
  2000年   8篇
  1999年   4篇
  1997年   1篇
  1996年   6篇
  1995年   7篇
  1994年   9篇
  1993年   5篇
  1992年   7篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   2篇
  1987年   3篇
  1985年   3篇
  1984年   3篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1980年   3篇
  1979年   2篇
  1977年   4篇
  1976年   1篇
  1975年   2篇
  1973年   1篇
  1970年   2篇
  1967年   1篇
  1966年   1篇
  1965年   1篇
  1955年   1篇
排序方式: 共有162条查询结果,搜索用时 375 毫秒
21.
The definition and properties of an abstract and very general nonparametric integral of the Calculus of Variations is presented. In harmony with the Lewy-McShane approach, the nonparametric integral ∝ f, for set functions ? taking their values in a Banach space E, is defined in terms of its associated parametric integral. For the latter use is made of the abstract parametric integral proposed by Cesari in Rn and then extended to Banach spaces by Breckenridge, Warner, and the authors. A condition (c) is shown to be relevant for the existence of the integral, and is preserved by the nonlinear operation f. Also, for f nonnegative, a Tonelli-type theorem is proved in the sense that the so defined Weierstrass integral ∝ f is always larger than or equal to the corresponding Lebesgue integral, and equality holds if and only if absolute continuity conditions hold. In the proof a suitable martingale is associated and a convergence theorem for martingales is applied. Applications to the calculus of variations will follow.  相似文献   
22.
23.
Sunto Si generalizzano condizioni sufficienti per la stabilità uniformemente asintotica e per l'instabilità espresse da alcuni teoremi di Matrosov. I risultati ottenuti sono utilizzabili anche nel caso che i secondi membri delle equazioni del moto siano funzioni non limitate. A Bruno Finzi nel suo 70mo compleanno. Lavoro eseguito nell'ambito dei Gruppi di ricerca matematica del C.N.R. Entrato in Redazione il 24 gennaio 1970.  相似文献   
24.
We introduce two new sufficient conditions for the existence of Burkill-Cesari integral: the «quasi additivity by refinement» and the «almost quasi additivity by refinement», that are intermediate between the well-known concepts of quasi additivity; moreover we study the behavior of these concepts in relation to subsets.  相似文献   
25.
Summary Boundary displacements in a large variety of membranes of revolution under live and dead loads are explicitely given. The boundary rotation is proved to be independent of the meridional shape for the dead load and identically zero for live loads under conditions often encountered in structural domes. To Mauro Picone on his 70th birth day.  相似文献   
26.
27.

Background

Antisense oligonucleotide (AON)-mediated exon skipping is a powerful tool to manipulate gene expression. In the present study we investigated the potential of exon skipping by local injection in the central nucleus of the amygdala (CeA) of the mouse brain. As proof of principle we targeted the splicing of steroid receptor coactivator-1 (SRC-1), a protein involved in nuclear receptor function. This nuclear receptor coregulator exists in two splice variants (SRC-1a and SRC-1e) which display differential distribution and opposing activities in the brain, and whose mRNAs differ in a single SRC-1e specific exon.

Methods

For proof of principle of feasibility, we used immunofluorescent stainings to study uptake by different cell types, translocation to the nucleus and potential immunostimulatory effects at different time points after a local injection in the CeA of the mouse brain of a control AON targeting human dystrophin with no targets in the murine brain. To evaluate efficacy we designed an AON targeting the SRC-1e-specific exon and with qPCR analysis we measured the expression ratio of the two splice variants.

Results

We found that AONs were taken up by corticotropin releasing hormone expressing neurons and other cells in the CeA, and translocated into the cell nucleus. Immune responses after AON injection were comparable to those after sterile saline injection. A successful shift of the naturally occurring SRC-1a:SRC-1e expression ratio in favor of SRC-1a was observed, without changes in total SRC-1 expression.

Conclusions

We provide a proof of concept for local neuropharmacological use of exon skipping by manipulating the expression ratio of the two splice variants of SRC-1, which may be used to study nuclear receptor function in specific brain circuits. We established that exon skipping after local injection in the brain is a versatile and useful tool for the manipulation of splice variants for numerous genes that are relevant for brain function.  相似文献   
28.
29.
Nine bis-9,10-dihydrophenanthrene and 9,10-dihydrophenanthrene/(dihydro)stilbene derivatives, including the new phochinenins G-L 16, were isolated from the whole plant of Pholidota chinensis. Their structures were elucidated on the basis of extensive spectroscopic investigations (1D, 2D NMR, and HR-EIMS). Owing to the sterically hindered rotation around the biaryl axis, some of these biaryl compounds can exist as a pair of enantiomers, but were isolated as racemates. Computed inversion barriers of selected atropisomeric derivatives suggested that phochinenins K 5, gymconpin C 7, and flavanthrin 9 have stable atropisomers. Their racemates were separated by HPLC on an optically active stationary phase, and were stereochemically characterized on-line by circular dichroism (CD) spectroscopy (LC-CD coupling), in conjunction with quantum-mechanics CD calculations.  相似文献   
30.
Large enhancements have been observed in the sub-barrier fusion cross sections for Ti+Ni systems in our previous studies. Coupled channel calculations incorporating couplings to 2+ and 3 states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer were carried out for 46,48Ti+61Ni systems. The present paper gives the results of these studies.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号