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排序方式: 共有186条查询结果,搜索用时 15 毫秒
61.
62.
Dönmez-Altuntas H Hamurcu Z Liman N Demirtas H Imamoglu N 《Biological trace element research》2006,112(3):241-246
Cadmium (Cd) is a toxic heavy metal that has been classified as a human carcinogen by the International Agency for Research
on Cancer. The genotoxic effects of cadmium oxide (CdO) were investigated in cultured dog lymphocytes after a short-term oral
CdO administration by the micronucleus (MN) test. The dogs were given 10 mg CdO/kg body weight per day for 3 and 28 d, respectively
group I (n=7) and group II (n=6). Blood samples were collected at the beginning of feeding and at 4 and 29 d after Cd administration and cultured for 72
h. Whereas no significant increase in the MN frequency in group I was observed (p=0.398), a significant MN induction with CdO was found in group II (p=0.028) when compared with initial MN frequencies of dogs in both groups. Our results suggest that CdO might be directly and/or
indirectly genotoxic after a monthly oral administration of CdO in dogs. 相似文献
63.
64.
乙酸铜对蚕豆根尖细胞致畸效应 总被引:11,自引:0,他引:11
采用蚕豆根尖细胞的微核试验和染色体畸变试验方法,以不同浓度的乙酸铜为诱变剂,选择不同的处理时间,测定蚕豆根尖细胞的有丝分裂指数、微核率和染色体畸变率。结果表明:乙酸铜能诱发较高频率的微核率,处理6h、12h时微核率均随着乙酸铜浓度的升高而增加,具有明显的剂量效应;处理24h时在实验浓度范围内,其微核率随乙酸铜浓度的升高而增加,但高于一定浓度后反而呈下降趋势。不同浓度的乙酸铜在不同处理时间均使蚕豆根尖细胞有丝分裂指数增大。乙酸铜还能诱导蚕豆根尖细胞产生较高频率的染色体畸变,且产生多种类型的染色体畸变。因此,乙酸铜对蚕豆根尖细胞具有明显的致畸效应。 相似文献
65.
本文采用80MeV/u的^12C^6 辐照番茄干种子,研究处于不同离子贯穿深度番茄干种子的辐照生物学效应,检测其生理生化指标。结果表明:辐照后不同贯穿深度上番茄种子的发芽势与物理剂量对应,第8层样品(对应于碳离子在水中的贯穿深度为15mm)出现峰值76.7%,发芽率随离子入射深度的变化不明显;不同贯穿深度辐照样品的根尖细胞微核率也与物理剂量相对应,在第6、7层样品中出现峰值0.257%;另外,辐照样品幼苗茎叶的一氧化氮合酶(NOS)活性、谷胱甘肽(GSH)含量及总抗氧化力在第9层出现峰值,谷胱甘肽过氧化物酶(GSH-PX)活性在第7-8层出现峰值,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性的变化与重离子贯穿深度没有明显的相关性。总而言之,本工作发现辐照品的多个生理生化指标均与入射离子的微剂量分布相对应,即存在生物效应峰。 相似文献
66.
Micheline Kirsch-Volders Toshio Sofuni Marilyn Aardema Silvio Albertini David Eastmond Michael Fenech Motoi Ishidate Jr. Stephan Kirchner Elisabeth Lorge Takeshi Morita Hannu Norppa Jordi Surralls Annelies Vanhauwaert Akihiro Wakata 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2003,540(2):153
At the Washington “2nd International Workshop on Genotoxicity Testing” (25–26 March 1999) current methodologies and data for the in vitro micronucleus test were reviewed. As a result, guidelines for the conduct of specific aspects of the protocol were developed. Agreement was achieved on the following topics: choice of cells, slide preparation, analysis of micronuclei, toxicity, use of cytochalasin-B, number of doses, and treatment/harvest times [Environ. Mol. Mutagen. 35 (2000) 167]. Because there were a number of important in vitro micronucleus validation studies in progress, it was not possible to design a definitive, internationally harmonized protocol at that time. These studies have now been completed and the data were reviewed at the Plymouth “3rd International Workshop on Genotoxicity Testing” (28–29 June 2002). Data from studies coordinated by the French Society of Genetic Toxicology, Japanese collaborative studies, European pharmaceutical industry validation studies, along with data from Lilly Research Laboratories were used to prepare conclusions on the main aspects of the in vitro micronucleus protocol. In this paper, the consensus agreements on the protocol for performing the in vitro micronucleus assay are presented. The major recommendations concern:
- 1. Demonstration of cell proliferation: both cell lines and lymphocytes can be used, but demonstration of cell proliferation in both control and treated cells is compulsory for the acceptance of the test.
- 2. Assessment of toxicity and dose range finding: assessment of toxicity should be performed by determining cell proliferation, e.g. increased cell counts (CC) or population doubling (PD) without cytochalasin-B, or e.g. cytokinesis-block proliferation index with cytochalasin-B; and by determining other markers for cytotoxicity (confluency, apoptosis, necrosis) which can provide valuable additional information.
- 3. Treatment schedules for cell lines and lymphocytes.
- 4. Choice of positive controls: without S9-mix both a clastogen (e.g. mitomycin C or bleomycin) and an aneugen (e.g. colchicine) should be included as positive controls and a clastogen that requires S9 for activity when S9-mix is used (e.g. dimethylnitrosamine, or cyclophosphamide in those cell types that cannot activate this agent directly).
- 5. Duplicate cultures and number of cells to be scored.
- 6. Repeat experiments: in lymphocytes, for each experiment blood from 2 different healthy young and non-smoking donors should be compared. In cell lines, the experiments need only to be repeated if the first one is negative.
- 7. Statistics: statistical significance should not be the sole factor for determining positive results. Biological meaning should serve as a guideline. Examples of statistical analyses are given.
67.
Zuhal Hamurcu Hamiyet Donmez Recep Saraymen Halil Demirtas 《Biological trace element research》2001,83(2):97-102
Micronuclei (MN) in blood lymphocytes were determined in 31 male workers occupationally exposed to lead (Pb), zinc (Zn), and
cadmium (Cd) and 20 control workers matched for age and smoking habits. Exposed workers have higher MN mean values than control
workers (p<0.01). In exposed workers, blood Pb concentrations were also significantly higher than in control workers (p<0.001), but the mean concentrations of Zn and Cd in the blood were not statistically significant compared to the controls
(p>0.05). These results suggest that lead may be genotoxic and the human lymphocyte micronucleus test can be used to assess
genotoxic effects that result from occupational exposures. 相似文献
68.
Miguel Alcaraz Encarnación Olmos Miguel Alcaraz-Saura Daniel G. Achel Julián Castillo 《Electromagnetic biology and medicine》2014,33(1):51-57
In recent years extremely low-frequency magnetic fields (ELF-EMF) have become widely used in human activities, leading to an increased chance of exposure to ELF-EMF. There are few reports on in vivo mammalian genotoxic effects using micronucleus (MN) assays, which generally have been used as a short-term screening system. We analyzed the possible genotoxic effect induced by long-term exposure (7, 14, 21, 28?d) of a 50?Hz ELM-MF to mice by measuring the increase in frequency of micronucleated polychromatic erythrocyte in their bone marrow (MNPCEs) and we compared it with that induced by 50?cGy of X-rays. Subsequently, we tried to reduce this chromosomal damage by administering four antioxidants substances with radioprotective capacities: dimethyl sulfoxide (DMSO), 6-n-propyl-2-thiouracil (PTU), grape-procyanidins (P) and citrus flavonoids extract (CE). The increase in micronucleated cells was higher in both physical treatments (Control?p?0.01) p?>?0.001)); however, the antioxidant substances only showed a genoprotective capacity against the damage induced by ionizing radiation (Ci?>?PTU?=?DMSO (p?0.001) >P?=?CE (p?0.001). The 50?Hz ELM-MF increased MNPCEs in mouse bone marrow, expressing a genotoxic capacity. Administration of antioxidant substances with radioprotective capacities known to act through the elimination of free radicals did not diminish the genotoxic effect induced by ELM-MF. 相似文献
69.
Differential DNA Amplification and Copy Number Control in the Hypotrichous Ciliate Euplotes crassus 总被引:1,自引:0,他引:1
ABSTRACT. During macronuclear development in hypotrichous ciliated protozoans, several thousand macronuclear DNA molecules are amplified several-hundred fold. We investigated the regulation of this amplification by determining the copy numbers of three different macronuclear DNA molecules in the hypotrichous ciliate Euplotes crassus. Two of the macronuclear DNA molecules were present in approximately 1,000 copies per cell, while the third was present in approximately 6,500 copies per cell. These reiteration levels were achieved either during macronuclear development, or shortly thereafter, and were maintained during vegetative growth. The most abundant macronuclear DNA molecule is present as a single-copy sequence in the micronuclear genome. Thus, its high copy number results from differential amplification. These results indicate that DNA amplification during macronuclear development is regulated individually for each macronuclear DNA molecule. 相似文献
70.
The mouse bone marrow micronucleus assay is anin vivo test commonly used in the pharmaceutical industry to evaluate the genotoxic potential of new compounds. The test detects agent-induced chromosomal damage or damage of the mitotic spindle apparatus. In this paper the state-of-the-art in automated rodent micronucleus evaluation using computerized image analyis in combination with high-quality slides obtained by the cellulose column fractionation technique is reviewed. The latter allows the effective removal of nucleated cells from rodent bone marrow. It has been found that automatic micronucleus scoring with the Leitz MIAC image analyzer is substantially faster than labor-intensive manual analysis. Automatic scoring can be performed overnight for up to 16 slides. We have been successfully using automatic micronucleus analysis for the testing of new pharmaceutical drugs for more than 3 years.Abbreviations MNE
NCE containing micronuclei
- MPE
PCE containing micronuclei
- NCE
normochromatic erythrocyte
- PCE
polychromatic erythrocyte
deceased on 25 May 1994 相似文献