全文获取类型
收费全文 | 2214篇 |
免费 | 57篇 |
国内免费 | 21篇 |
专业分类
化学 | 1506篇 |
晶体学 | 60篇 |
力学 | 31篇 |
数学 | 389篇 |
物理学 | 306篇 |
出版年
2023年 | 24篇 |
2022年 | 28篇 |
2021年 | 43篇 |
2020年 | 46篇 |
2019年 | 54篇 |
2018年 | 25篇 |
2017年 | 15篇 |
2016年 | 42篇 |
2015年 | 55篇 |
2014年 | 44篇 |
2013年 | 118篇 |
2012年 | 131篇 |
2011年 | 147篇 |
2010年 | 73篇 |
2009年 | 54篇 |
2008年 | 133篇 |
2007年 | 108篇 |
2006年 | 127篇 |
2005年 | 135篇 |
2004年 | 93篇 |
2003年 | 81篇 |
2002年 | 91篇 |
2001年 | 32篇 |
2000年 | 17篇 |
1999年 | 26篇 |
1998年 | 25篇 |
1997年 | 33篇 |
1996年 | 38篇 |
1995年 | 24篇 |
1994年 | 24篇 |
1993年 | 21篇 |
1992年 | 24篇 |
1991年 | 13篇 |
1990年 | 21篇 |
1989年 | 20篇 |
1988年 | 15篇 |
1987年 | 15篇 |
1986年 | 13篇 |
1985年 | 18篇 |
1984年 | 28篇 |
1983年 | 15篇 |
1982年 | 21篇 |
1981年 | 11篇 |
1980年 | 22篇 |
1979年 | 18篇 |
1978年 | 19篇 |
1977年 | 19篇 |
1976年 | 14篇 |
1975年 | 15篇 |
1974年 | 17篇 |
排序方式: 共有2292条查询结果,搜索用时 0 毫秒
1.
Susan Baker Lisa Kelchner Barbara Weinrich Linda Lee Paul Willging Robin Cotton Karen Zur 《Journal of voice》2006,20(4):631-641
Laryngotracheal stenosis is defined as a congenital or acquired narrowing of the airway. Congenital causes may include subglottic membranous or cartilaginous narrowing. Acquired causes may include trauma due to prolonged endotracheal or tracheal intubation or laryngotracheal injury. Although advances have been made over the past 30 years in reconstructive surgeries to improve airway patency in these patients, long-term laryngeal function for voice production is not well defined in this population. This review examines causes, symptoms and signs, and methods for diagnosing laryngotracheal stenosis. Surgical management procedures are briefly summarized. The current literature on voice outcomes is summarized. The predominant voice characteristics in the population are presented, although results are challenged by the heterogeneity of voice presentation and paucity of data from instrumental measures. Considerations for subjective and instrumental assessment, measures of quality of life, instrumental methods, and treatment options specific to the needs of this population are discussed. Research strategies to identify long-term outcomes of surgical and behavioral treatments in this population are posed. 相似文献
2.
Two groups of 10 speech-language pathology graduate students were each given 7 weeks of singing lessons to determine whether voice lessons could have an effect on their clinical and perceptual skills. Pre-, mid-, and posttests to measure various skills were designed and implemented. With use of paired sample statistical testing, statistically significant results were obtained. In addition, the subjective responses of the students show that the lessons were effective in improving pitch perception, breath control, and legato production or easy onset. This study supports efforts to integrate curricula in vocal performance and speech-language pathology. 相似文献
3.
4.
5.
6.
7.
Auvergne R. Saint‐Loup R. Joly‐Duhamel C. Robin J. J. Boutevin B. 《Journal of polymer science. Part A, Polymer chemistry》2007,45(7):1324-1335
The synthesis and characterization of photopolymerizable unsaturated polyester resins based on PET waste are described. The resins came from a depolymerization process based on the glycolysis of PET by diethylene glycol (DEG). Different molecular weights of glycolysates were synthesized. Then, the latter was functionalized by a methyl hemiester of maleic acid to obtain unsatured α,ω‐bismaleate PET oligomers. In the presence of an electron donor monomer, such as triethylene glycol divinyl ether, these electron acceptor oligomers were copolymerized by way of charge‐transfer complexes under UV irradiation. The reaction was monitored in situ by real‐time IR spectroscopy to study the kinetics of photopolymerization. This one was studied in relation with the physical and chemical characteristics of oligoesters and the composition of mixtures containing divinyl ethers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1324–1335, 2007 相似文献
8.
Microarrays are a popular technology to study genes that are differentially expressed between two conditions. In this Note, we propose an iterative procedure to determine the biggest subset of non-differentially expressed genes. We prove a pseudo Markov relationship that allows practical computations. We obtain explicit expressions for FDR and the level of the proposed test at each step. To cite this article: A. Bar-Hen, S. Robin, C. R. Acad. Sci. Paris, Ser. I 337 (2003). 相似文献
9.
10.
A rooted graph is a pair (G,x), where G is a simple undirected graph and x ∈ V(G). If G is rooted at x, its kth rotation number hk (G,x) is the minimum number of edges in a graph F of order |G| + k such that for every v ∈ V(F) we can find a copy of G in F with the root vertex x at v. When k = 0, this definition reduces to that of the rotation number h(G,x), which was introduced in [“On Rotation Numbers for Complete Bipartite Graphs,” University of Victoria, Department of Mathematics Report No. DM-186-IR (1979)] by E.J. Cockayne and P.J. Lorimer and subsequently calculated for complete multipartite graphs. In this paper, we estimate the kth rotation number for complete bipartite graphs G with root x in the larger vertex class, thereby generalizing results of B. Bollobás and E.J. Cockayne [“More Rotation Numbers for Complete Bipartite Graphs,” Journal of Graph Theory, Vol. 6 (1982), pp. 403–411], J. Haviland [“Cliques and Independent Sets,” Ph. D. thesis, University of Cambridge (1989)], and J. Haviland and A. Thomason [“Rotation Numbers for Complete Bipartite Graphs,” Journal of Graph Theory, Vol. 16 (1992), pp. 61–71]. © 1993 John Wiley & Sons, Inc. 相似文献