全文获取类型
收费全文 | 652篇 |
免费 | 39篇 |
国内免费 | 1篇 |
专业分类
化学 | 547篇 |
晶体学 | 2篇 |
力学 | 6篇 |
数学 | 32篇 |
物理学 | 105篇 |
出版年
2023年 | 10篇 |
2022年 | 12篇 |
2021年 | 10篇 |
2020年 | 29篇 |
2019年 | 6篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 27篇 |
2015年 | 26篇 |
2014年 | 23篇 |
2013年 | 38篇 |
2012年 | 41篇 |
2011年 | 43篇 |
2010年 | 31篇 |
2009年 | 22篇 |
2008年 | 50篇 |
2007年 | 42篇 |
2006年 | 35篇 |
2005年 | 48篇 |
2004年 | 19篇 |
2003年 | 15篇 |
2002年 | 15篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 4篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1974年 | 3篇 |
1973年 | 8篇 |
1972年 | 3篇 |
1968年 | 2篇 |
1935年 | 2篇 |
1933年 | 6篇 |
排序方式: 共有692条查询结果,搜索用时 15 毫秒
41.
42.
Christiane Lorenz Harald Hagendorfer Natalie von Goetz Ralf Kaegi Robert Gehrig Andrea Ulrich Martin Scheringer Konrad Hungerbühler 《Journal of nanoparticle research》2011,13(8):3377-3391
Consumer spray products are already on the market in the cosmetics and household sector, which suggest by their label that
they contain engineered nanoparticles (ENP). Sprays are considered critical for human health, because the lungs represent
a major route for the uptake of ENP into the human body. To contribute to the exposure assessment of ENP in consumer spray
products, we analyzed ENP in four commercially available sprays: one antiperspirant, two shoe impregnation sprays, and one
plant-strengthening agent. The spray dispersions were analyzed by inductively coupled plasma mass spectrometry (ICPMS) and
(scanning-) transmission electron microscopy ((S)TEM). Aerosols were generated by using the original vessels, and analyzed
by scanning mobility particle sizer (SMPS) and (S)TEM. On the basis of SMPS results, the nanosized aerosol depositing in the
respiratory tract was modeled for female and male consumers. The derived exposure levels reflect a single spray application.
We identified ENP in the dispersions of two products (shoe impregnation and plant spray). Nanosized aerosols were observed
in three products that contained propellant gas. The aerosol number concentration increased linearly with the sprayed amount,
with the highest concentration resulting from the antiperspirant. Modeled aerosol exposure levels were in the range of 1010 nanosized aerosol components per person and application event for the antiperspirant and the impregnation sprays, with the
largest fraction of nanosized aerosol depositing in the alveolar region. Negligible exposure from the application of the plant
spray (pump spray) was observed. 相似文献
43.
44.
Carl A. Batt Anna M. Waldron Natalie Broadwater 《Journal of nanoparticle research》2008,10(7):1141-1148
Nanotechnology will be an increasing part of the everyday lives of most people in the world. There is a general recognition
that few people understand the implications of the technology, the technology itself or even the definition of the word. This
lack of understanding stems from a lack of knowledge about science in general but more specifically difficulty in grasping
the size scale and symbolism of nanotechnology. A potential key to informing the general public is establishing the ability
to comprehend the scale of nanotechnology. Transitioning from the macro to the nanoscale seems to require an ability to comprehend
scales of one-billion. Scaling is a skill not common in most individuals and tests of their ability to extrapolate size based
upon scaling a common object demonstrates that most individuals cannot scale to the extent needed to make the transition to
nanoscale. Symbolism is another important vehicle to providing the general public with a basis to understand the concepts
of nanotechnology. With increasing age, individuals are able to draw representations of atomic scale objects, but these tend
to be iconic and the different representations not easily translated. Ball and stick models are most recognized by the public,
which provides an opportunity to present not only useful symbolism but also a reference point for the atomic scale. 相似文献
45.
Banerjee and Andrade generated axially symmetric electrovac solutions from the spherically symmetric Reissner-Nordström solution by giving a complex translation along theZ axis. We use the same method for generating new more complicated axially symmetric solutions from known solutions. Several such examples are given. 相似文献
46.
The growth of magnetic energy density is considered in a collapsing ferrofluid with infinite electrical conductivity whose magnetic permeability is not a constant. It is shown that the variation of the magnetic permeability affects the growth of magnetic energy. The case of isotropic collapse and a specific case of anisotropic collapse are examined. 相似文献
47.
Investigation of dual-channel fiber-optic surface plasmon resonance sensing for biological applications 总被引:1,自引:0,他引:1
A dual-channel fiber-optic sensor based on surface plasmon resonance (SPR) for self-referencing refractive-index measurements has been proposed. Most applications of fiber-optic SPR sensors are designed to measure the refractive index of a liquid or gas sample by measuring the signal from a single surface, the sensitivity and stability of which is easily affected by the fluctuation of external environmental conditions. We have designed a dual-channel fiber-optic surface sensor with two independent SPR signals from two areas of the same probe. A prototype sensor was fabricated and characterized. The preliminary experimental results demonstrate the characteristic responses of both SPR signals from two channels that independently correspond to the refractive index changes in the liquid samples with which they are in contact. The design could be extended to a multichannel sensor with further developments. The experimental results confirmed that one channel can be used as a reference sensor that could compensate for unexpected changes in bulk refraction or temperature and develop this sensor as a practicable high-sensitivity biosensing device. 相似文献
48.
We report a new approach to analyze both vapor and liquid phases by utilizing a tapered fiber optic surface plasmon resonance (SPR) probe. This technique employs a fiber optic SPR probe with a modified geometry to tune the SPR coupling wavelength-angle pair. The observed composite spectrum included two distinct SPR dips associated with surface plasmons excited in the gas and liquid active regions. This sensor is able to detect refractive index changes in both vapor and liquid phases individually by simultaneous monitoring SPR coupling wavelengths from the two sensing surfaces. 相似文献
49.
Glycopeptides were isolated from functional units of two molluscan hemocyanins (Hcs). They were analyzed and localized in the sequences. A comparison with potential N-glycosylation sites of two other molluscan Hcs was made. An immunological cross-reactivity was observed between the beta-Hc and the alpha-macroglobulin of Helix pomotia. ELISA experiments with glycopeptide fractions indicated a competition. 相似文献
50.
Václav Štengl Snejana Bakardjieva Natalie Murafa Eva Večerníková Jan Šubrt Vladimír Balek 《Journal of nanoparticle research》2007,9(3):455-470
A new method for preparation of titania nanowires with diameter around 10 nm and length up to 2–3 μm is described. The precursor
was prepared from sodium titanate by adding ethylene glycole (EG) and heating at temperature of 198°C for 6 h under reflux.
The sodium titanate glycolate formed by this way aggregated into 1D nanostructures and was subsequently transformed into titania
glycolate during a chemical treatment with 98% sulfuric acid. Titania nanowires with variable amount of anatase and rutile
were prepared by heating to temperatures in the range 350–1000°C. The precursor as well as titania based samples were characterized
by X-ray diffraction, Infrared spectroscopy, Scanning electron microscopy, High resolution transmission microscopy, Thermogravimetry,
Differential thermal analysis, Evolved gas analysis and Emanation thermal analysis. The nitrogen adsorption/desorption was
used for surface area and porosity determination. The photoactivity of the prepared titania samples was assessed by the photocatalytic
decomposition of 4-chlorophenol in an aqueous slurry under UV irradiation of 365 nm wavelength. 相似文献