全文获取类型
收费全文 | 270篇 |
免费 | 7篇 |
专业分类
化学 | 223篇 |
力学 | 3篇 |
数学 | 12篇 |
物理学 | 39篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 1篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 11篇 |
2012年 | 18篇 |
2011年 | 14篇 |
2010年 | 11篇 |
2009年 | 8篇 |
2008年 | 12篇 |
2007年 | 12篇 |
2006年 | 16篇 |
2005年 | 16篇 |
2004年 | 14篇 |
2003年 | 17篇 |
2002年 | 13篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1971年 | 1篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1906年 | 1篇 |
1894年 | 1篇 |
排序方式: 共有277条查询结果,搜索用时 15 毫秒
21.
The optimizer developed for the Mining Minima algorithm, which uses ideas from Genetic Algorithms, the Global Underestimator Method, and Poling, has been adapted for use in ligand-receptor docking. The present study describes the resulting methodology and evaluates its accuracy and speed for 27 test systems. The performance of the new docking algorithm appears to be competitive with that of previously published methods. The energy model, an empirical force field with a distance-dependent dielectric treatment of solvation, is adequate for a number of test cases, although incorrect low-energy conformations begin to compete with the correct conformation for larger sampling volumes and for highly solvent-exposed binding sites that impose little steric constraint on the ligand. 相似文献
22.
Yu Na Shin Byung Soo Kim Hyun Hee Ahn Kyung Sook Kim Moon Suk Kim Gilson Khang 《Applied Surface Science》2008,255(2):293-296
Corona discharge treatment was applied to modify the surface of polyethylene (PE). The wettability of PE surface was gradually increased by power increase of a corona treatment along the PE length, indicating that the hydrophilicity of PE surface increased gradually. The adhesion and proliferation behavior of human bone marrow stem cells (hBMSCs) on the gradient PE surface was evaluated. We found that hBMSCs were adhered to and proliferated on better highly hydrophilic than hydrophobic surfaces. The plot of proliferation rate vs. the water contact angles was parabolic. These results indicate that surface wettability plays an important role in the cell attachment and proliferation. 相似文献
23.
Mario Ribeiro de Melo-Júnior Jorge Luiz Silva Araújo-Filho Consuelo Antunes Barreto Lins Nicodemos Teles de Pontes-Filho Luiz Bezerra de CarvalhoJr 《Applied biochemistry and biotechnology》2010,160(8):2198-2207
This work aimed to immobilize the antibody anti-galectin-3 onto polysiloxane–polyvinyl alcohol (POS-PVA) support, to evaluate
its capacity to capture the serum antigen galectin-3 and to quantify by ELISA the antigen levels in sera from patients with
prostatic adenocarcinoma (PA) and benign prostatic hyperplasia (BPH) and healthy individuals. Also, for comparative effect,
the galectin-3 expression in the prostate tissue through immunohistochemistry was evaluated. The optical density (galectin-3
level) values established for the sera from PA and BPH patients were lower compared with those found for the healthy individuals.
Galectin-3 immunohistochemically showed a significant increase and reduction of the cytoplasmatic protein expression in BPH
and PA, respectively, compared with the normal prostate. These results showed that POS-PVA disks could be used as solid phase
to immobilize serum galectins and in immunoassays procedures for the correspondent IgG anti-galectins detection in human sera. 相似文献
24.
S. Di Maria S. Barros J. Bento P. Teles C. Figueira M. Pereira P. Vaz G. Paulo 《Radiation measurements》2011,46(10):1103-1108
The main purpose of this study was to validate and compare Mean Glandular Dose (MGD) values obtained using Monte Carlo simulations with experimental values obtained from Entrance Surface Dose (ESD) and depth dose measurements performed in a Hospital mammography unit. ESD and depth dose were measured using ThermoLuminescent Dosimeters (TLDs), and a tissue equivalent mammography phantom recommended by the American College of Radiology (ACR). Measurements and Monte Carlo simulations were also compared with the MGD calculated using the Automatic Exposure Control (AEC) system of the mammographic unit. In the simulations the Doppler energy broadening effect was also taken into account. The simulated ESD are about 5%–10% higher than the measured ESD values. The deviation between the measured and simulated MGD values in the phantom is of about 15%. The MGD evaluated using the AEC system is smaller both with respect to the Monte Carlo simulation and experimental result by a factor of about 15% and 25% respectively. Moreover the BackScatter Factor (BSF) estimated by Monte Carlo simulations was used for the MGD calculation according to the Wu’s method. Finally the inclusion of the energy broadening effect on MGD calculation produces negligible variations on the simulated results. 相似文献
25.
J. G. Gilson 《International Journal of Theoretical Physics》1969,2(3):281-292
A discrete subquantum classical dynamics is used to show that the conventional definition of quantum probability can be regarded as being reducible. In terms of this basis, a solution is suggested to a difficulty which is encountered in the phase space theory of quantum processes and it is also indicated how a strictly measure theoretical approach to quantum path weighting could be achieved. 相似文献
26.
The Negishi cross-coupling reaction of vinylic- and aryltellurides with heteroarylzinc chlorides catalyzed by PdCl2/CuI is described. This cross-coupling reaction is general and permits the formation of a new sp2-sp2 carbon bond in good yields and high stereoselectivity. 相似文献
27.
28.
29.
30.
The structures of trimethylene oxide and sulphide have been studied by the nematic liquid crystal N.M.R. method. Corrections for the ring puckering motion have been applied and structures determined in conjunction with data from microwave spectroscopic studies. Improved results are obtained if a third motional constant is included in the analysis. 相似文献