全文获取类型
收费全文 | 345篇 |
免费 | 18篇 |
国内免费 | 2篇 |
专业分类
化学 | 275篇 |
晶体学 | 2篇 |
力学 | 1篇 |
数学 | 33篇 |
物理学 | 54篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 11篇 |
2013年 | 20篇 |
2012年 | 24篇 |
2011年 | 34篇 |
2010年 | 9篇 |
2009年 | 20篇 |
2008年 | 18篇 |
2007年 | 31篇 |
2006年 | 23篇 |
2005年 | 23篇 |
2004年 | 10篇 |
2003年 | 17篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1976年 | 1篇 |
1971年 | 3篇 |
1968年 | 1篇 |
1903年 | 1篇 |
排序方式: 共有365条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
For any weighted space HV(G) of holomorphic functions on an open set G ? ?Nwith a topology stronger than that of uniform convergence on the compact sets and for any quasibarrelled space E we prove the topological isomorphism $HV(G,E_{b}^{\prime})={\cal L}_b(E,HV(G))$ and derive a similar, more complicated isomorphism for weighted spaces of continuous functions. This generalizes results of [3], [7] and [6] and should be compared with the ∈-product representations for the corresponding spaces of functions with o-growth conditions. At the end we also show the topological isomorphism HV1(G1, HV2(G2)) = H (V1 ? V2)(G1 × G2). 相似文献
95.
96.
Rózyło TK Siembida R Nemeth ZI Albert L Tyihak E 《Biomedical chromatography : BMC》2000,14(3):173-179
Taking into consideration the unquestionable intracellular occurrence of formaldehyde (HCHO) and its generators in cells of plant, animal and human organisms as well as in body fluids it was resolved to determine their levels in hard tissues of physiologically and pathologically changed teeth. The aim of the work was to determine the relationship between the level of HCHO and the levels of its generators in pathologically changed teeth, mainly carietic teeth as tooth caries is still a serious and commonly occurring problem. The occurrence of HCHO (captured as its dimedone adduct) and some of its potential generators was demonstrated in the hard tissues of healthy and pathological human teeth by means of OPLC, HPLC and MS analyses. It was established that the measurable level of HCHO was increased in the carietic teeth in comparison with healthy ones. In the case of paradontic tooth sample, a dramatic increase of HCHO was observed and at the same time the level of betaines was decreased considerably. The obtained results give a new insight into the pathology of hard tissues of teeth in strong correlation with the phases of stress syndrome. 相似文献
97.
Silke I. Nitsche Edwin Weber Wilhelm Seichter Nikoletta Báthori Kayrat M. Beketov Gerhard Roewer 《Silicon Chemistry》2003,2(1-2):55-71
New organosilicon compounds 1–3 featuring bulky triphenylsilyl moieties attached to rigid linear or trigonal spacer units have been synthesized and demonstrated to act as clathrate hosts, yielding crystalline inclusion compounds mostly with apolar and aprotic dipolar guest molecules, while the nonbulky dimethylphenylsilyl or trimethylsilyl substituted analogous compounds 4 and 5, which were also synthesized, proved inefficient. X-ray crystal structures of the inclusion compounds 1·DMF (1:1), 1·pyridine (1:1), 2·1,4-dioxane (2:1), 2·pyridine (2:1), 2·p-xylene (2:1), 2·H2O (2:1) as well as of the unsolvated compounds 2 and 5 are described, and thermal stability studies of selected clathrates are reported. 相似文献
98.
Rathgeber S Pakula T Wilk A Matyjaszewski K Beers KL 《The Journal of chemical physics》2005,122(12):124904
We measured the form factor of bottle-brush macromolecules under good solvent conditions with small-angle neutron scattering and static light scattering. The systems under investigation are brushes, synthesized via the grafting-from route, built from a poly(alkyl methacrylate) backbone to which poly(n-butyl acrylate) side chains are densely grafted. The aim of our work is to study how the systematic variation of structural parameters such as the side chain length and backbone length change the conformation of the polymer brushes in solution. All spectra can be consistently described by a model, considering the bottle-brush polymers as flexible rods with internal density fluctuations. Parameters discussed are (1) the contour length per main chain monomer l(b), (2) the fractal dimension of the side chains Ds, as well as (3) the fractal dimension D, and (4) the Kuhn length lambdak of the overall brush. l(b)=0.253+/-0.008 nm is found to be independent of the side chain length and equal to the value found for the bare main chain, indicating a strongly stretched conformation for the backbone due to the presence of the side chains. The fractal dimension of the side chains is determined to be Ds=1.75+/-0.07 which is very close to the value of 10.588 approximately 1.70 expected for a three-dimensional self-avoiding random walk (3D-SAW) under good solvent conditions. On larger length scales the overall brush appears to be a 3D-SAW itself (D=1.64+/-0.08) with a Kuhn-step length of lambdak=70+/-4 nm. The value is independent of the side chain length and 46 times larger than the Kuhn length of the bare backbone (lambdak=1.8+/-0.2 nm). The ratio of Kuhn length to brush diameter lambda(k)d>or=20 determines whether lyotropic behavior can be expected or not. Since longer side chains do not lead to more persistent structures, lambda(k)d decreases from 8 to 4 with increasing side chain length and lyotropic behavior becomes unlikely. 相似文献
99.
100.
Krol S Nolte M Diaspro A Mazza D Magrassi R Gliozzi A Fery A 《Langmuir : the ACS journal of surfaces and colloids》2005,21(2):705-709
The immobilization of cells in defined arrays (cell patterning) is a key step towards cell-based biosensors or other cell-based devices. While cell patterning is usually achieved by modifying the surface on which only the cells should adhere and leaving the cells unmodified, we present here a different approach in which cells are first coated with polyelectrolytes and subsequently immobilized on patterned surfaces. By coating, the cells are protected and their interactions with the substrate are modified such that patterning is simplified. We used microcontact printing of polyelectrolytes to structure surfaces such that regions of opposite charges and the same charge as the cell coating were present and found that we can thus achieve patterning of the coated yeast cells. In accordance with prior work, we find that coating does not kill the cells and coated GFP-expressing cells still function after immobilization, which we checked by fluorescence microscopy. 相似文献