全文获取类型
收费全文 | 6032篇 |
免费 | 135篇 |
国内免费 | 46篇 |
专业分类
化学 | 3770篇 |
晶体学 | 38篇 |
力学 | 213篇 |
数学 | 1274篇 |
物理学 | 918篇 |
出版年
2022年 | 56篇 |
2021年 | 57篇 |
2020年 | 65篇 |
2019年 | 69篇 |
2018年 | 59篇 |
2017年 | 49篇 |
2016年 | 96篇 |
2015年 | 119篇 |
2014年 | 136篇 |
2013年 | 314篇 |
2012年 | 301篇 |
2011年 | 329篇 |
2010年 | 226篇 |
2009年 | 210篇 |
2008年 | 313篇 |
2007年 | 317篇 |
2006年 | 309篇 |
2005年 | 274篇 |
2004年 | 269篇 |
2003年 | 217篇 |
2002年 | 209篇 |
2001年 | 101篇 |
2000年 | 92篇 |
1999年 | 98篇 |
1998年 | 73篇 |
1997年 | 66篇 |
1996年 | 90篇 |
1995年 | 66篇 |
1994年 | 75篇 |
1993年 | 82篇 |
1992年 | 65篇 |
1991年 | 43篇 |
1990年 | 76篇 |
1989年 | 61篇 |
1988年 | 48篇 |
1987年 | 53篇 |
1986年 | 47篇 |
1985年 | 68篇 |
1984年 | 81篇 |
1983年 | 51篇 |
1982年 | 79篇 |
1981年 | 79篇 |
1980年 | 94篇 |
1979年 | 76篇 |
1978年 | 80篇 |
1977年 | 76篇 |
1976年 | 71篇 |
1975年 | 51篇 |
1974年 | 38篇 |
1973年 | 58篇 |
排序方式: 共有6213条查询结果,搜索用时 0 毫秒
21.
Paul Ruelle Michel Buchmann Hô Nam-Tran Ulrich W. Kesselring 《Journal of computer-aided molecular design》1992,6(5):431-448
Summary The thermodynamics of mobile order is applied to predict the aqueous solubility of liquid and solid aliphatic and polycyclic aromatic hydrocarbons. The solubility values are mainly determined by the magnitude of the hydrophobic effect. However, contrary to the solubilities of the alkanes, the solubilities of polycyclic aromatic hydrocarbons in water predicted in absence of solute-solvent hydrogen (H) bonds are systematically too low. This shows the contribution of weak specific interactions between the OH groups and the electrons of the aromatic substances. According to the theory, these interactions are characterized by a stability bility constant Ko which can be derived from solubility data. At 25°C, this constant amounts to 80 cm3/mol, the order of magnitude of which can be explained by the competition of these intermolecular bonds with the rather weak self-association bonds in the secondary chains of water. 相似文献
22.
Michel Talagrand 《Inventiones Mathematicae》1992,107(1):1-40
Summary Forq>2, an operator fromC(K) toX is of cotypeq if and only if it factors through the Lorentz space
. Forq=2, ifX is a rearrangement invariant space on [0, 1], the injectionC([0, 1])X is of cotype 2 if and only if it factors through the Lorentz space
; but there is a cotype 2 operator C(K) that does not factor through
. If a Banach latticeX satisfies the Orlicz property, any bounded lattice operatorT:C(K)X is of cotype 2. We however construct a Banach lattice with the Orlicz property, but that fails to be of cotype 2.Oblatum 4-VII-1990 & 18-IV-1991Work partially supported by an NSF grant 相似文献
23.
24.
Hans Fritz Rolf Gleiter Michel Nastasi Jean-Luc Schuppiser Jacques Streith 《Helvetica chimica acta》1978,61(8):2887-2898
3-Substituted 1-iminopyridinium ylides 1 undergo photo-induced ring enlargement to 1H-1,2-diazepines. With strongly electron-withdrawing substituents the ring expansion process is regiospecific and leads exclusively to 4-substituted 1 H-1, 2-diazepines. Weak electron-donating substituents, like a methyl group and halogen atoms, do not have any directing effect since both 4- and 6-substituted 1 H -1,2-diazepines are obtained. With strong electron-donating substituents no diazepines are formed; instead one observes photo-induced isomerization to the 2-aminopyridine derivatives, the process being non-regiospecific. Regiospecific photo-induced ring expansion processes are explained in terms of a simple HMO model. 相似文献
25.
Michel Talagrand 《Mathematische Annalen》1979,240(2):97-102
Resumé On construit un groupe compact et une sous-mesure pathologique sur ce groupe dont la convolée avec la mesure de Haar n'est pas pathologique. 相似文献
26.
Quentin Coquerel Claire Legendre Jacinthe Frangieh Stephan De Waard Jrme Montnach Leos Cmarko Joseph Khoury Charifat Said Hassane Dimitri Brard Benjamin Siegler Ziad Fajloun Harold De Pomyers Kamel Mabrouk Norbert Weiss Daniel Henrion Pascal Richomme Csar Mattei Michel De Waard Anne-Marie Le Ray Christian Legros 《Molecules (Basel, Switzerland)》2022,27(13)
Voltage-gated Na+ (NaV) channels are significant therapeutic targets for the treatment of cardiac and neurological disorders, thus promoting the search for novel NaV channel ligands. With the objective of discovering new blockers of NaV channel ligands, we screened an In-House vegetal alkaloid library using fluorescence cell-based assays. We screened 62 isoquinoline alkaloids (IA) for their ability to decrease the FRET signal of voltage sensor probes (VSP), which were induced by the activation of NaV channels with batrachotoxin (BTX) in GH3b6 cells. This led to the selection of five IA: liriodenine, oxostephanine, thalmiculine, protopine, and bebeerine, inhibiting the BTX-induced VSP signal with micromolar IC50. These five alkaloids were then assayed using the Na+ fluorescent probe ANG-2 and the patch-clamp technique. Only oxostephanine and liriodenine were able to inhibit the BTX-induced ANG-2 signal in HEK293-hNaV1.3 cells. Indeed, liriodenine and oxostephanine decreased the effects of BTX on Na+ currents elicited by the hNaV1.3 channel, suggesting that conformation change induced by BTX binding could induce a bias in fluorescent assays. However, among the five IA selected in the VSP assay, only bebeerine exhibited strong inhibitory effects against Na+ currents elicited by the hNav1.2 and hNav1.6 channels, with IC50 values below 10 µM. So far, bebeerine is the first BBIQ to have been reported to block NaV channels, with promising therapeutical applications. 相似文献
27.
28.
29.
Abstract The equilibrium distribution of chloride or nitrate counter-ions of K or NH4 co-ions and of water is determined experimentally at different degrees of ionization X[xbar] of hydrophylic weak-base aminated polyvinyl-alcohol membranes. These data are analyzed and explained in terms of thermodynamics interrelating the molality of fixed-charge densities and of counter-ions to that of the amount of water and of diffused salt in the membrane. Three domains have to be considered: the polyelectrolyte domain with small external concentration compared to the internal net fixed charge concentration (notion of “net-charge” densities), the domain of homogeneous interstitial liquid of the concentrated electrolyte type with sufficiently concentrated salt solution, and the intermediate domain. 相似文献
30.
Abstract Radical copolymerization kinetics of vinyl chloride (VC) and vinyl bromide (VB) lead to the following reactivity ratios rVC=0.825 rVB=1.05 Vinyl bromide acts as a chain transfer agent, more powerful than vinyl chloride, the transfer constant for VC radicals being 8.5 × 10?3 at 40° C. Neither thermal nor ionic degrad-ation produce controlled distribution of short diene sequences in the copolymer. In the ionic process initiated with LiCl or LiBr in dimethylformamide solution, substitution of halogen atoms as well as acid elimination takes place. 相似文献