全文获取类型
收费全文 | 438篇 |
免费 | 5篇 |
国内免费 | 5篇 |
专业分类
化学 | 321篇 |
晶体学 | 6篇 |
力学 | 10篇 |
数学 | 34篇 |
物理学 | 77篇 |
出版年
2024年 | 6篇 |
2023年 | 12篇 |
2022年 | 17篇 |
2021年 | 16篇 |
2020年 | 23篇 |
2019年 | 15篇 |
2018年 | 17篇 |
2017年 | 20篇 |
2016年 | 16篇 |
2015年 | 6篇 |
2014年 | 27篇 |
2013年 | 35篇 |
2012年 | 31篇 |
2011年 | 31篇 |
2010年 | 19篇 |
2009年 | 18篇 |
2008年 | 17篇 |
2007年 | 20篇 |
2006年 | 16篇 |
2005年 | 6篇 |
2004年 | 12篇 |
2003年 | 19篇 |
2002年 | 10篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1983年 | 1篇 |
1981年 | 4篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1962年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有448条查询结果,搜索用时 15 毫秒
131.
Kapil Parihar Surya Shekhar Daga Umema Ahmed G. K. Mathur Supriya Kumari Jyoti Kumawat Mahipal Singh Sankhla 《Macromolecular Symposia》2024,413(1):2300056
Accurate gender determination is crucial in many scientific disciplines, especially in prenatal diagnosis of X-linked diseases and forensic investigations. Today, molecular techniques, especially typing for a length variation in the X–Y homologous amelogenin gene (AMEL X and AMEL Y), are used for gender assignation. This amelogenin is an integral part of most PCR multiplex kits for gender determination marker, but in 1998 there was a report of two normal males being typed as female with this marker. Subsequently, a small number of males with amelogenin deleted genes have been reported in various populations but little data are available characterizing these deletions. This review aims to explore possible relationships among the AMEL Y deleted samples and Y-chromosome microsatellite haplotypes. Also, attempts are made to determine the frequency of males with AMEL Y deleted gene in various countries across the globe. Although some studies have shown that males with AMEL Y deleted gene are extremely rare in most populations, typing an additional gender-determining locus should be considered in forensic investigations where the reference sample is of unknown gender. 相似文献
132.
Bikshandarkoil R. Srinivasan Jyoti V. Sawant Pallepogu Raghavaiah 《Journal of Chemical Sciences》2007,119(1):11-20
The reaction of hydrated magnesium or calcium 4-nitrobenzoate (4-nba) generated in situ, with imidazole (Im) results in the formation of the complexes [Mg(H2O)2(Im)2(4-nba)2] 1 and [Ca(H2O)3(Im)(4-nba)2]·Im 2, which exhibit the same metal:4-nba:Im ratio but different degrees of hydration. Complex 1 crystallizes in the triclinic Pī space group and the Mg atom is located on an inversion centre, while 2 crystallizes in the monoclinic P21/c space group and all atoms are located in general positions. In 1 the Im ligands, which are trans to each other, are coordinated to Mg, while 2 contains coordinated as well as free Im. The monodentate 4-nba ligands are disposed trans to each other in 1, while they adopt a cis orientation in 2 resulting in different supramolecular structures. Complex 1 exhibits two types of H-bonding interactions namely O-H···O and
N-H···O, while in 2 three varieties of H-bond, viz. O-H···O, N-H···O and O-H···N are observed. The Im ligand ligand functions as a bifurcated
H-bond donor in 1 while the O atom of the nitro group functions as a H-bond acceptor. In contrast, the nitro group in 2 is not involved in any H-bonding interactions. The free Im in 2 functions as a bifurcated acceptor and forms an extended chain linking adjacent complex molecules. The chains thus formed
are further cross-linked with the aid of H-donor bonds from both the free as well as the coordinated Im. Both 1 and 2 exhibit π-π stacking interactions. Complex 1 is thermally more stable as compared to 2, and both complexes can be dehydrated to the corresponding anhydrous complexes by heating at 140 and 100°C respectively.
At elevated temperatures, both the complexes can be pyrolysed to the corresponding oxide. The anhydrous complexes can be rehydrated
to obtain the starting hydrated materials. 相似文献
133.
134.
Romesh Chandra Boruah Purabi Devi J. S. Sandhu 《Journal of heterocyclic chemistry》1979,16(8):1555-1557
Some 7-melhyl-substituted-2,1-benzisoxazoles and cyclopropanobenzofurazan oxides are synthesized and characterized by their elemental and spectral analyses. 相似文献
135.
Jyoti K Parikh 《Pramana》1976,6(1):42-58
The energy levels of21, 23Na,22, 23Ne,24, 28Mg and25, 29Al are obtained by mixing various bands using the projected deformed Hartree-Fock (DHF) method. Solutions having minimum energies
are found to be prolate for all the nuclei considered here. Higher bands are obtained either by considering particle-hole
excitations or oblate solutions. These various bands are mixed using the projection method and care has been taken to orthogonalize
the bands. The interactions used in this study are those given by Kuo, Preedom-Wildenthal (PW) and WHMK interactions. The
last one seems to give good results for most of the nuclei considered here. Not only are the lowest bands well-reproduced
but the second lowest bands agree reasonably well in most nuclei. The third lowest ones obtained in some nuclei are not yet
observed as complete bands. However, K obtained for the third band seems to be correct. A comparison with shell model calculations—which
are numerically exhausting—shows similar results for the lowest band. However, the agreement of the second band varies from
nucleus to nucleus. A comparison between matrix elements of the interactions is made to analyze the results. 相似文献
136.
Newton MA Jyoti B Dent AJ Fiddy SG Evans J 《Chemical communications (Cambridge, England)》2004,(21):2382-2383
Synchronous, time resolved, infra-red, XAFS, and mass spectroscopies are simultaneously applied in situ to the investigation of the dynamic behaviour of Rh/Al2O3 catalysts during NO reduction by CO; NO conversion, and its kinetic character are closely correlated to the conversion of Rh(I)(predominantly RhI(CO)2) to Rh(0). 相似文献
137.
Sally A. Goldman Jyoti Parwatikar Subhash Suri 《Journal of Algorithms in Cognition, Informatics and Logic》2000,34(2):370
We study non-preemptive, online admission control in the hard deadline model: each job must either be serviced prior to its deadline or be rejected. Our setting consists of a single resource that services an online sequence of jobs; each job has a length indicating the length of time for which it needs the resource and a delay indicating the maximum time it can wait for the service to be started. The goal is to maximize total resource utilization. The jobs are non-preemptive and exclusive, meaning once a job begins, it runs to completion, and at most one job can use the resource at any time. We obtain a series of results, under varying assumptions of job lengths and delays. 相似文献
138.
We prove that the “naive” convolution Dirichlet series $D_{2}(s)$ attached to a degree 2 Siegel Hecke cusp form $F$ , has a pole at $s=1$ . As an application, we write down the asymptotic formula for the partial sums of the squares of the eigenvalues of $F$ with an explicit error term. Further, as a corollary, we are able to show that the abscissa of absolute convergence of the (normalized) spinor-zeta function attached to $F$ is $s = 1$ . 相似文献
139.
Pallav Jyoti Pal Mainul Haque Prashanta Kumar Mandal 《Mathematical Methods in the Applied Sciences》2014,37(16):2429-2450
The present investigation deals with a predator–prey model with disease that spreads among the predator species only. The predator species is split out into two groups—the susceptible predator and the infected predator both of which feeds on prey species. The stability and bifurcation analyses are carried out and discussed at length. On the basis of the normal form theory and center manifold reduction, the explicit formulae are derived to determine stability and direction of Hopf bifurcating periodic solution. An extensive quantitative analysis has been performed in order to validate the applicability of our model under consideration. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
140.
Pabitra Kumar Kalita Susanta Kumar Borthakur Runumi Das Chandan Jyoti Choudhury 《合成通讯》2013,43(21):2444-2453
This paper describes a general method for the synthesis of homoallylic alcohols and amines by nucleophilic addition reaction of allyltributylstannane to carbonyl compounds and aldimines where iodine acts as a catalyst in H2O/acetic acid (1:1) medium. Only 10 mol% of I2 is required for various organic transformations. By using this process, various homoallylic alcohols and amines are produced in good to excellent yields. 相似文献