全文获取类型
收费全文 | 644篇 |
免费 | 14篇 |
国内免费 | 3篇 |
专业分类
化学 | 425篇 |
晶体学 | 5篇 |
力学 | 23篇 |
数学 | 94篇 |
物理学 | 114篇 |
出版年
2021年 | 11篇 |
2019年 | 4篇 |
2017年 | 10篇 |
2016年 | 22篇 |
2015年 | 10篇 |
2014年 | 9篇 |
2013年 | 44篇 |
2012年 | 28篇 |
2011年 | 33篇 |
2010年 | 23篇 |
2009年 | 25篇 |
2008年 | 31篇 |
2007年 | 25篇 |
2006年 | 36篇 |
2005年 | 26篇 |
2004年 | 15篇 |
2003年 | 9篇 |
2002年 | 28篇 |
2001年 | 12篇 |
2000年 | 12篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 11篇 |
1988年 | 18篇 |
1987年 | 5篇 |
1986年 | 8篇 |
1985年 | 12篇 |
1984年 | 15篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 9篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1971年 | 3篇 |
1935年 | 4篇 |
1933年 | 3篇 |
排序方式: 共有661条查询结果,搜索用时 62 毫秒
31.
Ryan E Campbell-Anson Diane Kentor Yi J Wang Kathryn M Bushnell Yufeng Li Luis M Vence Laszlo G Radvanyi 《Journal of immune based therapies and vaccines》2008,6(1):1
Background
Human monocyte-derived DC (mDC) loaded with peptides, protein, tumor cell lysates, or tumor cell RNA, are being tested as vaccines against multiple human malignancies and viral infection with great promise. One of the factors that has limited more widespread use of these vaccines is the need to generate mDC in large scale. Current methods for the large-scale cultivation of mDC in static culture vessels are labor- and time- intensive, and also require many culture vessels. Here, we describe a new method for the large-scale generation of human mDC from human PBMC from leukopheresis or buffy coat products using roller bottles, never attempted before for mDC generation. We have tested this technology using 850 cm2 roller bottles compared to conventional T-175 flat-bottom static culture flasks. 相似文献32.
Hegedus L Kirschner N Wittmann M Simon P Noszticzius Z Amemiya T Ohmori T Yamaguchi T 《Chaos (Woodbury, N.Y.)》1999,9(2):283-297
The polarization curve of an acid-base interface in a hydrogel medium has a diode characteristic. Two of each such electrolyte diodes can be combined to give an electrolyte transistor. When a salt is added to the alkaline or to the acidic part of a reverse biased electrolyte diode, the current response is highly nonlinear. If the salt is added to the acidic side, even bistability can be observed. This bistability can generate complex oscillations in a base-acid-base electrolyte transistor. These nonlinear effects are studied experimentally and theoretically. While the nonlinear salt effect can be explained with the Nernst-Planck equations, to understand the bistable behavior further investigations are necessary. (c) 1999 American Institute of Physics. 相似文献
33.
Amine(N? B)-aminoborane internal complexes and 1,3,2-diazaborolidines were recently identified as intermediates of the borane reduction of imidazolidino[1,2-d]dithiazepines. Theoretical Mo calculations were used to obtain the structural, conformational, and electronic properties and heats of formation of the boron compounds in the framework of the semiempirical AM 1 approximation. Internal constraints in the bicyclic system were analyzed through comparisons with the calculated molecular geometries, electron distribution of monocyclic, and open-chain models. The geometry of the five-membered diazaborolidine systems becomes distorted upon building up the complex bicyclic structure, compared to the nearly planar monocycles. The weak coordinative nitrogen–boron bond (calculated bond order around 0.5) in the internal complexes exerts less conformational strains in the adjoining nine-membered ring containing the disulfide than does the covalent N? B bond in the corresponding 1,2,3-diazaborolidine. Thus, the internal constraints of the bicyclic system is taken up by the five-membered ring to a lesser degree in the 1,3,2diazaborolidine than in the internal complex. © 1992 John Wiley & Sons, Inc. 相似文献
34.
M. Petrascu A. Isbasescu I. Lazar I. Mihai H. Petrascu A. T. Rudchik V. A. Chernievski O. A. Ponkratenko V. A. Ziman 《Zeitschrift für Physik A Hadrons and Nuclei》1993,345(4):395-399
The energy spectra and angular distributions of products in the reaction27Al(14N,X) have been measured at 116 MeV bombarding energy. It is shown that the energy spectra of the products lighter than the projectile, are well described by a three-body breakup calculation. The experimental total breakup cross-section estimated in the present work, together with Glas-Mosel calculation of the fusion cross-section, are in a reasonable agreement with the optical model total reaction cross-section. 相似文献
35.
Stéphane Chalais Alfred Delville Christian Detellier André Gerstmans Pierre Laszlo 《Journal of solution chemistry》1983,12(1):33-40
Intrinsic formation constants for complexes of Na+ ions with a series of polyamines have been determined from23Na NMR measurements in binary mixtures of tetrahydrofuran (THF) and amines. The results show in a totally unambiguous manner a regular decrease in the magnitude of the chelate effect with the number of atoms intervening between the nitrogen ligators. The key assumption, tetracoordination of the cation, is critically examined, and experimental evidence is adduced in its support. 相似文献
36.
A. J. Lazar 《Israel Journal of Mathematics》1969,7(4):357-364
LetX be a polyhedral Banach space whose dual is anL
1(μ) space for some measureμ. Then for each Banach spacesY ⊆Z and each compact operatorT: Y →X there exists a norm preserving compact extension
Z →X. 相似文献
37.
Rudolf Taube Karl Seyferth Lajos Bencze Laszlo Markó 《Journal of organometallic chemistry》1976,111(2):215-223
The reaction of di- and mono-nitrosylmolybdenum complexes with C2H5-AlCl2, AlCl3 and Al(C2H5)3 under argon and CO was followed IR-spectroscopically. Some conclusions were reached concerning the nature of the catalyticactivity of the complex in olefin metathesis. 相似文献
38.
Intranasal irradiation with the xenon chloride ultraviolet B laser improves allergic rhinitis 总被引:1,自引:0,他引:1
Csoma Z Ignacz F Bor Z Szabo G Bodai L Dobozy A Kemeny L 《Journal of photochemistry and photobiology. B, Biology》2004,75(3):137-144
We earlier reported that the 308 nm xenon chloride (XeCl) ultraviolet B (UVB) laser is highly effective for the treatment of inflammatory skin diseases. Since UVB irradiation has been shown to exert both local and systemic immunosuppression, we investigated the clinical efficacy of UVB irradiation in allergic rhinitis. In an open study, groups of patients with severe allergic rhinitis received intranasal irradiation with a 308 nm XeCl UVB excimer laser for two weeks. In the low-dose group (n=10), treatment was given twice weekly, starting with 0.25x the individual minimal erythema dose (MED), whereas patients in the medium-dose group (n=8) were treated four times weekly, starting with 0.4x MED. In each group, the dosage was gradually increased. Evaluation was based on the symptom scores. The effect of the XeCl laser on the skin prick test reaction was also studied. In the low-dose group, seven patients completed the study, and there was no improvement in the nasal symptoms. In the medium-dose group, the XeCl UVB irradiation significantly inhibited the rhinorrhoea, the sneezing, the nasal obstruction and the total nasal score (p<0.05). The XeCl UVB excimer laser also inhibited the allergen-induced skin prick test in a dose-dependent manner. These results suggest that the XeCl UVB excimer laser might serve as a new therapeutic tool in the treatment of allergic rhinitis. 相似文献
39.
40.
For a second order elliptic equation with a nonlinear radiation-type boundary condition on the surface of a three-dimensional domain, we prove existence of generalized solutions without explicit conditions (like
) on the trace of solutions. In the boundary condition, we admit polynomial growth of any fixed degree in the unknown solution, and the heat exchange and emissivity coefficients may vary along the radiating surface. Our generalized solution is contained in a Sobolev space with an exponent q which is greater than
for the fourth power law. 相似文献