全文获取类型
收费全文 | 328篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学 | 231篇 |
晶体学 | 5篇 |
力学 | 9篇 |
数学 | 32篇 |
物理学 | 56篇 |
出版年
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 12篇 |
2012年 | 9篇 |
2011年 | 11篇 |
2010年 | 6篇 |
2009年 | 8篇 |
2008年 | 8篇 |
2007年 | 12篇 |
2006年 | 3篇 |
2005年 | 9篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 14篇 |
2001年 | 4篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 12篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 10篇 |
1978年 | 10篇 |
1977年 | 13篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 8篇 |
1969年 | 2篇 |
1965年 | 2篇 |
1963年 | 2篇 |
1962年 | 8篇 |
1960年 | 3篇 |
1958年 | 7篇 |
1957年 | 2篇 |
1954年 | 2篇 |
排序方式: 共有333条查询结果,搜索用时 421 毫秒
41.
Prem K. Mehrotra Jayaraman Chandrasekhar Periakaruppan T. Manoharan Sankaran Subramanian 《Chemical physics letters》1979,68(1):219-221
The nonempirical NDDO MO method in its unrestricted form has been used to evaluate isotropic hyperfine coupling constants and nuclear spin-spin coupling constants. Satisfactory agreement with INDO and experimental results is obtained. 相似文献
42.
A relaxed version of Karmarkar's method is developed. This method is proved to have the same polynomial time complexity as Karmarkar's method and its efficient implementation using inexact projections is discussed. Computational results obtained using a preliminary implementation of the method are presented which indicate that the method is practicable.This research was supported in part by NSF Grants CDR 84-21402 and DMS-85-12277 and ONR Contract N00014-87-K-0214. 相似文献
43.
An “average state” of a molecule is defined by distributing the electrons equally among the valence orbitals of a minimal
basis set Hartree-Fock calculation. The resulting eigenvalues, called tempered orbital energies, behave much more like the
Mulliken-Walsh diagram energies or extended Hückel eigenvalues than do the Hartree-Fock canonical orbital energies. 相似文献
44.
Agfacontour film has simplified photographic procedures so that equidensity techniques can now be applied in photoelastic practice and other work requiring evaluation of optical fringes for fractional orders. Direct photography and copying from conventional negatives are described and practical considerations indicated. 相似文献
45.
46.
47.
Jayaraman Chandrasekhar Prem K. Mehrotra Sankaran Subramanian Periyakaruppan T. Manoharan 《Theoretical chemistry accounts》1979,52(4):303-310
Three valence-only schemes based on the Roby version of NDDO MO theory, which differ only in the core-valence treatment and the choice of the basis set, have been applied to the study of molecules containing first-row atoms. Orbital energies, charge distribution, dipole moments, field gradients, and a few other one-electron molecular properties are calculated to satisfactory accuracy. The schemes appear unreliable in the prediction of barriers to internal rotation in molecules, presumably due to errors in the core contribution to the total energy. An alternative treatment is suggested. 相似文献
48.
Jay Jin Saranya Kittanakom Victoria Wong Beverly AS Reyes Elisabeth J Van Bockstaele Igor Stagljar Wade Berrettini Robert Levenson 《BMC neuroscience》2010,11(1):33
Background
Opioid agonist drugs produce analgesia. However, long-term exposure to opioid agonists may lead to opioid dependence. The analgesic and addictive properties of opioid agonist drugs are mediated primarily via the mu-opioid receptor (MOR). Opioid agonists appear to alter neuronal morphology in key brain regions implicated in the development of opioid dependence. However, the precise role of the MOR in the development of these neuronal alterations remains elusive. We hypothesize that identifying and characterizing novel MOR interacting proteins (MORIPs) may help to elucidate the underlying mechanisms involved in the development of opioid dependence. 相似文献49.
Eti Mehrotra Jyotsna Vishwakarma Avinash C. Tripathi Pankaj K. Sonar 《Natural product research》2019,33(4):568-572
The present study explored the schizonticidal potential of traditionally used Magnolia champaca (L.) Baill. ex. Pierre flowers, identifying constituents of interest. The extraction of phytoconstituents was carried out by microwave-assisted technique, isolated via column chromatography, and characterised by various physicochemical, spectral (IR, 1H-NMR and Mass) and chromatographic (HPTLC) techniques. Both the isolated compounds (parthenolide and costunolide diepoxide) exhibited potent schizonticidal antimalarial activity during primary screening in rodent models, with maximum parasitaemia suppression (85.18% and 83.65%, respectively) at a dose of 20 mg/kg body weight when compared to the standard drugs chloroquine and artesunate. In silico techniques were employed to identify the probable biological target and mechanism of action of these isolated compounds. Molecular docking studies also predicted the binding orientations and multi-targeted action of these compounds, in particular costunolide diepoxide with maximum affinity towards SERCA and DHFR proteins. Additionally, favourable in silico ADMET parameters were envisaged through various computational programmes. 相似文献
50.
The phenomenon of proton emission is treated as a process of asymmetric fission through a one-dimensional potential barrier
developed due to combined effects of the Coulomb potential, centrifugal potential and various renormalization processes. The
barrier is simulated to an asymmetric, smooth and analytically solvable potential with adjustable depth, shape and range.
The half-lives of proton emitters in the mass range A = 105–171 have been calculated using exact expression for the transmission coefficients. Good agreement with the experimental
data is obtained by the adjustment of just one parameter in all the cases.
相似文献