全文获取类型
收费全文 | 166篇 |
免费 | 11篇 |
国内免费 | 4篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2020年 | 9篇 |
2019年 | 14篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 13篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 6篇 |
2009年 | 4篇 |
2008年 | 8篇 |
2007年 | 12篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 5篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 5篇 |
排序方式: 共有181条查询结果,搜索用时 500 毫秒
11.
Ecotoxicological tests (or bioassays) are controlled, reproducible tests where ecological responses are determined quantitatively. Due to numerous difficulties arising when airborne emissions are sampled, relatively few ecotoxicological assays have been applied. Aerosol particles are generally collected on a filter, which limits the quantity of the sample, thus also limiting the range of available test organisms. Bacterial bioassays require low sample quantity, and make a good choice when eco‐ or genotoxicity of the sample are to be determined. Of bacterial assays, the bioluminescence inhibition test has been proven applicable for assessing toxicity of airborne contaminants. In this paper diverse test protocols and their modifications are reviewed. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
12.
13.
Carolina Ruiz Zambon Vania Helena Techio Luiz Fernando de Oliveira da Silva Adelson Francisco de Oliveira 《Plant biosystems》2019,153(1):68-76
The study evaluated the microsporogenesis of olive trees subjected to different agricultural pesticide applications during flowering. Inflorescences of cultivars Arbequina and MGS GRAP541 were subjected to agricultural pesticides: mineral oil, neem oil, dimethoate and deltamethrin. The floral buds were fixed in Carnoy for the microsporogenesis analysis and in Karnovsky for scanning electron microscopy. The slides were prepared by squash technique and staining with propionic carmine. The pollen viability was determined by Alexander’s stain and in vitro germination. Results show that the quantification of abnormalities in meiosis in the two cultivars caused significant effect among the treatments, being that all differed statistically from the control group. Both methods showed a higher percentage of viable pollens in the control treatment and lower percentage of viability with the agricultural pesticides. The method of pollen viability by staining presented the highest averages of viable pollens, but when compared together, both methods presented a strongly related positive linear correlation. It was concluded that the used chemical products increased the percentage of chromosomal abnormalities during microsporogenesis, which interfered in the pollen viability of the two analyzed cultivars. The product deltamethrin caused the strongest effect on meiosis and on pollen viability. 相似文献
14.
15.
Stepan A. Kremis Dmitry S. Baev Alla V. Lipeeva Elvira E. Shults Tatiana G. Tolstikova Olga I. Sinitsyna Alexey V. Kochetov Tatiana S. Frolova 《Journal of biochemical and molecular toxicology》2019,33(11)
The furocoumarin backbone is a promising platform for chemical modifications aimed at creating new pharmaceutical agents. However, the high level of biological activity of furocoumarins is associated with a number of negative effects. For example, some of the naturally occurring ones and their derivatives can show genotoxic and mutagenic properties as a result of their forming crosslinks with DNA molecules. Therefore, a particularly important area for the chemical modification of natural furocoumarins is to reduce the negative aspects of their bioactivity. By studying a group of 21 compounds—1,2,3‐triazolyl modified derivatives of furocoumarin and peucedanin—using the SOS chromotest, the Ames test, and DNA‐comet assays, we revealed modifications that can neutralize the structure's genotoxic properties. Theoretical aspects of the interaction of the compound library were studied using molecular modeling and this identified the leading role of the polyaromatic molecular core that takes part in stacking‐interactions with the pi‐systems of the nitrogenous bases of DNA. 相似文献
16.
Marzin D 《Cell biology and toxicology》1999,15(6):359-365
New developments in mutagenic risk assessment have appeared in the past few years. New methods have been developed such asin vitro micronucleus assay for chromosomal alterations, comet assay for primary DNA damage, use of transgenic animals to detectin vivo gene mutations, and fluorescent in situ hybridization method to detect aneuploidy. Other new methods will be developed in the few next years, including the use of
DNA chips and the use of molecular biological methods. Several micromethods have been developed to test a great number of
chemical compounds. New concepts have appeared concerning interpretation of data, and particularly of thresholds especially
in the case of aneugens; in some cases metabolic or mechanistic thresholds were demonstrated. Genotoxic studies are best integrated
into toxicological testing: for example, some genotoxicity tests can be integrated into subacute toxicology; interpretation
of data includes metabolism; and toxicokinetic data relate to other toxicological studies. Conversely, genotoxicity data can
be used to interpret toxicology studies.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
The comet assay for DNA damage and repair 总被引:9,自引:0,他引:9
Collins AR 《Molecular biotechnology》2004,26(3):249-261
The comet assay (single-cell gel electrophoresis) is a simple method for measuring deoxyribonucleic acid (DNA) strand breaks
in eukaryotic cells. Cells embedded in agarose on a microscope slide are lysed with detergent and high salt to form nucleoids
containing supercoiled loops of DNA linked to the nuclear matrix. Electrophoresis at high pH results in structures resembling
comets, observed by fluorescence microscopy; the intensity of the comet tail relative to the head reflects the number of DNA
breaks. The likely basis for this is that loops containing a break lose their supercoiling and become free to extend toward
the anode. The assay has applications in testing novel chemicals for genotoxicity, monitoring environmental contamination
with genotoxins, human biomonitoring and molecular epidemiology, and fundamental research in DNA damage and repair. The sensitivity
and specificity of the assay are greatly enhanced if the nucleoids are incubated with bacterial repair endonucleases that
recognize specific kinds of damage in the DNA and convert lesions to DNA breaks, increasing the amount of DNA in the comet
tail. DNA repair can be monitored by incubating cells after treatment with damaging agent and measuring the damage remaining
at intervals. Alternatively, the repair activity in a cell extract can be measured by incubating it with nucleoids containing
specific damage. 相似文献
18.
19.
Oncogenic hyperplasia is the first and inevitable stage of formation of a (solid) tumor. This stage is also the core of many other proliferative diseases. The present work proposes the first minimal model that combines homeorhesis with oncogenic hyperplasia where the latter is regarded as a genotoxically activated homeorhetic dysfunction. This dysfunction is specified as the transitions of the fluid of cells from a fluid, homeorhetic state to a solid, hyperplastic-tumor state, and back. The key part of the model is a nonlinear reaction-diffusion equation (RDE) where the biochemical-reaction rate is generalized to the one in the well-known Schlögl physical theory of the non-equilibrium phase transitions. A rigorous analysis of the stability and qualitative aspects of the model, where possible, are presented in detail. This is related to the spatially homogeneous case, i.e. when the above RDE is reduced to a nonlinear ordinary differential equation. The mentioned genotoxic activation is treated as a prevention of the quiescent G0-stage of the cell cycle implemented with the threshold mechanism that employs the critical concentration of the cellular fluid and the nonquiescent-cell-duplication time. The continuous tumor morphogeny is described by a time-space-dependent cellular-fluid concentration. There are no sharp boundaries (i.e. no concentration jumps exist) between the domains of the homeorhesis- and tumor-cell populations. No presumption on the shape of a tumor is used. To estimate a tumor in specific quantities, the model provides the time-dependent tumor locus, volume, and boundary that also points out the tumor shape and size. The above features are indispensable in the quantitative development of antiproliferative drugs or therapies and strategies to prevent oncogenic hyperplasia in cancer and other proliferative diseases. The work proposes an analytical-numerical method for solving the aforementioned RDE. A few topics for future research are suggested. 相似文献
20.
Lack of direct DNA damage in human blood leukocytes and lymphocytes after in vitro exposure to high power microwave pulses 总被引:3,自引:0,他引:3
Chemeris NK Gapeyev AB Sirota NP Gudkova OY Tankanag AV Konovalov IV Buzoverya ME Suvorov VG Logunov VA 《Bioelectromagnetics》2006,27(3):197-203
Currently, the potential genotoxicity of high power microwave pulses (HPMP) is not clear. Using the alkaline single cell gel electrophoresis assay, also known as the alkaline comet assay, we studied the effects of HPMP (8.8 GHz, 180 ns pulse width, peak power 65 kW, pulse repetition frequency 50 Hz) on DNA of human whole-blood leukocytes and isolated lymphocytes. The cell suspensions were exposed to HPMP for 40 min in a rectangular waveguide. The average SAR calculated from the temperature kinetics was about 1.6 kW/kg (peak SAR was about 300 MW/kg). The steady-state temperature rise in the 50 microl samples exposed to HPMP was 3.5 +/- 0.1 degrees C. In independent experiments, we did not find any statistically significant DNA damage manifested immediately after in vitro HPMP exposure of human blood leukocytes or lymphocytes or after HPMP exposure of leukocytes subsequently incubated at 37 degrees C for 30 min. Our results indicate that HPMP under the given exposure conditions did not induce DNA strand breaks, alkali-labile sites, and incomplete excision repair sites, which could be detected by the alkaline comet assay. 相似文献