首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   73篇
  免费   9篇
  国内免费   9篇
基础医学   3篇
临床医学   3篇
内科学   17篇
特种医学   1篇
外科学   1篇
综合类   15篇
预防医学   28篇
药学   20篇
中国医学   1篇
肿瘤学   2篇
  2021年   2篇
  2020年   1篇
  2019年   4篇
  2018年   1篇
  2017年   3篇
  2016年   1篇
  2015年   2篇
  2014年   3篇
  2013年   5篇
  2012年   1篇
  2011年   4篇
  2010年   4篇
  2009年   3篇
  2008年   1篇
  2007年   4篇
  2006年   6篇
  2005年   5篇
  2004年   1篇
  2003年   2篇
  2002年   3篇
  2001年   3篇
  2000年   1篇
  1999年   1篇
  1998年   2篇
  1997年   1篇
  1995年   4篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1991年   4篇
  1990年   5篇
  1989年   6篇
  1988年   1篇
  1987年   2篇
排序方式: 共有91条查询结果,搜索用时 31 毫秒
1.
  1. The metabolism of deltamethrin (DLM), cis-permethrin (CPM) and trans-permethrin (TPM) was studied in liver microsomes, liver cytosol and plasma from male Sprague–Dawley rats aged 15, 21 and 90 days and from adult humans.

  2. DLM and CPM were metabolised by rat hepatic microsomal cytochrome P450 (CYP) enzymes and to a lesser extent by microsomal and cytosolic carboxylesterase (CES) enzymes, whereas TPM was metabolised to a greater extent by CES enzymes.

  3. In human liver, DLM and TPM were mainly metabolised by CES enzymes, whereas CPM was metabolised by CYP and CES enzymes.

  4. The metabolism of pyrethroids by cytosolic CES enzymes contributes to the overall hepatic clearance of these compounds.

  5. DLM, CPM and TPM were metabolised by rat, but not human, plasma CES enzymes.

  6. This study demonstrates that the ability of male rats to metabolise DLM, CPM and TPM by hepatic CYP and CES enzymes and plasma CES enzymes increases with age. In all instances, apparent intrinsic clearance values were lower in 15 than in 90?day old rats. As pyrethroid-induced neurotoxicity is due to the parent compound, these results suggest that DLM, CPM and TPM may be more neurotoxic to juvenile than to adult rats.

  相似文献   
2.
  1. The metabolism of the pyrethroids deltamethrin (DLM), cis-permethrin (CPM) and trans-permethrin (TPM) was studied in human expressed cytochrome P450 (CYP) and carboxylesterase (CES) enzymes.

  2. DLM, CPM and TPM were metabolised by human CYP2B6 and CYP2C19, with the highest apparent intrinsic clearance (CLint) values for pyrethroid metabolism being observed with CYP2C19. Other CYP enzymes contributing to the metabolism of one or more of the three pyrethroids were CYP1A2, CYP2C8, CYP2C9*1, CYP2D6*1, CYP3A4 and CYP3A5. None of the pyrethroids were metabolised by CYP2A6, CYP2E1, CYP3A7 or CYP4A11.

  3. DLM, CPM and TPM were metabolised by both human CES1 and CES2 enzymes.

  4. Apparent CLint values for pyrethroid metabolism by CYP and CES enzymes were scaled to per gram of adult human liver using abundance values for microsomal CYP enzymes and for CES enzymes in liver microsomes and cytosol. TPM had the highest and CPM the lowest apparent CLint values for total metabolism (CYP and CES enzymes) per gram of adult human liver.

  5. Due to their higher abundance, all three pyrethroids were extensively metabolised by CES enzymes in adult human liver, with CYP enzymes only accounting for 2%, 10% and 1% of total metabolism for DLM, CPM and TPM, respectively.

  相似文献   
3.
Deltamethrin (DLM) is a well‐known pyrethroid insecticide used extensively in pest control. Exposure to DLM has been demonstrated to cause apoptosis in various cells. However, the immunotoxic effects of DLM on mammalian system and its mechanism is still an open question to be explored. To explore these effects, this study has been designed to first observe the interactions of DLM to immune cell receptors and its effects on the immune system. The docking score revealed that DLM has strong binding affinity toward the CD45 and CD28 receptors. In vitro study revealed that DLM induces apoptosis in murine splenocytes in a concentration‐dependent manner. The earliest markers of apoptosis such as enhanced reactive oxygen species and caspase 3 activation are evident as early as 1 h by 25 and 50 µM DLM. Western blot analysis demonstrated that p38 MAP kinase and Bax expression is increased in a concentration‐dependent manner, whereas Bcl 2 expression is significantly reduced after 3 h of DLM treatment. Glutathione depletion has been also observed at 3 and 6 h by 25 and 50 µM concentration of DLM. Flow cytometry results imply that the fraction of hypodiploid cells has gradually increased with all the concentrations of DLM at 18 h. N‐acetyl cysteine effectively reduces the percentage of apoptotic cells, which is increased by DLM. In contrast, buthionine sulfoxamine causes an elevation in the percentage of apoptotic cells. Phenotyping data imply the effect of DLM toxicity in murine splenocytes. In brief, the study demonstrates that DLM causes apoptosis through its interaction with CD45 and CD28 receptors, leading to oxidative stress and activation of the mitochondrial caspase‐dependent pathways which ultimately affects the immune functions. This study provides mechanistic information by which DLM causes toxicity in murine splenocytes. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 808–819, 2016.  相似文献   
4.
溴氰菊酯致大鼠慢性中毒的肝组织形态学观察   总被引:1,自引:1,他引:0  
目的探讨溴氰菊酯对大鼠肝组织结构的慢性损伤作用。方法选取大鼠32只,随机分为空白对照组(Ⅰ组)、橄榄油对照组(Ⅱ组)、溴氰菊酯1.56 mg/kg组(Ⅲ组)、溴氰菊酯6.25 mg/kg组(Ⅳ组),每组8只。Ⅲ、Ⅳ组连续6个月经口灌胃染毒,Ⅱ组只给予相当剂量的橄榄油,观察大鼠染毒期间行为学变化,测定肝脏器系数,肝组织切片经苏木精-伊红染色和PAS染色,观察肝细胞形态学变化和肝细胞糖原含量的变化。结果染毒组大鼠出现流涎、大汗、立毛等中毒症状。苏木精-伊红染色显示Ⅲ、Ⅳ组肝细胞胞浆疏松,内可见脂滴,肝血窦淤血。染毒组大鼠肝细胞的糖原含量有不同程度降低,Ⅳ组与Ⅰ、Ⅱ、Ⅲ组相比,Ⅲ组和Ⅰ组相比差异有统计学意义(F=9.015,q=3.675~10.058,P<0.05);但Ⅲ组与Ⅱ组比较,差异无统计学意义(q=0.672,P>0.05)。Ⅲ、Ⅳ组肝脏器系数与其他各组比较,差异均有统计学意义(F=10.737,q=3.945~9.968,P<0.05)。结论长期低剂量摄入溴氰菊酯可造成大鼠肝组织的慢性损伤,并具有剂量-效应关系。  相似文献   
5.
用拟除虫菊酯亚致死剂量处理中华按蚊,显示该蚊的生存力和繁殖率降低。以胺菊酯或溴氰菊酯处理中华按蚊,产卵的胚胎发育减慢。溴氰菊酯致死的部分中华按蚊幼虫体长缩短。  相似文献   
6.
国外迄今尚未见有急性拟除虫菊酯中毒的临床报告。国内医学文献自1982年至1988年则已报道急性拟除虫菊酯中毒共573例,其中生产性中毒229例,意外性中毒344例。以急性溴氰菊酯中毒最为多见(325例),其次为戊氰菊酯(196例)及氯氰菊酯(45例)等急性中毒。本文对573例急性拟除虫菊酯中毒的临床表现进行综述与分析,并探讨其诊断分级与鉴别诊断,为制定职业性急性拟除虫菊酯中毒诊断标准提供参考。  相似文献   
7.
为探讨混合喷洒拟菊酯与有机磷对施药员健康的影响,作者等在河北产棉区进行了流行病学调查和生物监测研究。混合喷洒拟菊酯与有机磷和单纯喷洒拟菊酯两组人群在不良反应率和中毒率上未见明显差别。混喷组施药员全血胆碱酯酶活性也未见明显变化。混喷组施药员尿中拟菊酯原型的排泄有高于单纯喷洒组的趋势,尿中代谢物Br_2A未见增加。结果表明,在本文观察的接触水平下,混合喷洒拟菊酯与有机磷杀虫剂对施药员健康的影响未超过单纯喷洒拟菊酯者。  相似文献   
8.
An experiment was conducted to determine whether spraying with a broad-spectrum pyrethroid insecticide in grassland habitat for the control of grasshoppers could affect nesting songbirds through the removel of insect food resources. Three 81 ha plots were sprayed at the recommended rate of Decis 5F (6.25 g deltamethrin ha–1). Paired control plots remained unsprayed. The density of (Acrididae) grasshoppers was monitored throughout the spring and summer. The nests of chestnut-collared longspurs (Calcarius ornatus) were monitored to determine the nest and nestling survival rates, size at fledging and food habits. Attributes of parental foraging were quantified. Food selection by parents and consumption by nestlings were measured using oesophageal ligatures. Grasshoppers accounted for >85% of the biomass of the nestling diet to spraying and this proportion increased throughout the season in unsprayed plots. Applications of Decis 5F initially reduced the grasshopper density by 93%. After spraying, parent birds switched to other arthropod taxa less affected by insecticide application; the overall biomass fed to nestlings was not significantly reduced although the acridid proportion declined to <30%. The weight and skeletal size of the nestlings at fledging was unaffected. Parent birds in sprayed plots flew no further to feed their nestlings at a similar rate to that of birds in the control plots. The clutch size and nestling survival were similar between the sprayed and unsprayed plots after Decis 5F application, but egg success was lower in the sprayed plots compared to the control plots (67 versus 87%, p < 0.05)  相似文献   
9.
目的:研究应用溴氰菊酯浸泡蚊帐时疟疾媒介嗜人按蚊对杀虫剂产生抗药性的潜力,方法:交配后3-5d龄的的雌性嗜人按蚊通过溴氰菊酯药帐吸豚鼠血,控制蚊虫48h死亡率于50%左右,存活蚊产卵并按常规方法饲养传代,连续选育18代,每两对幼虫及成蚊进行敏感度测定,求出幼虫半数致死浓度(LC50)、成蚊半数击倒时间(KT50)、成半数致死时间(LT50),并计算各自的抗性指数。结果:选育过程中按蚊幼虫抗性指数均小于2.0,成蚊抗性指数也小于2.0,结论:模拟溴氰菊酯浸泡蚊帐条件下嗜人按蚊对溴氰菊酯产生抗药性的潜力小,提示局部选择性应用菊酯杀虫可能对媒介按蚊的抗性抗压力较小,可延长菊酯杀虫剂使用寿命。  相似文献   
10.
Continuous and indiscriminate use of pesticides, especially in tropical countries for public health or agriculture purpose, has led many vector populations to become resistant to organochlorides, organophosphates, and even to carbamates and pyrethroids. Development of resistance by a vector population has been one of the reasons for the failure of the control measures in many countries. This investigation demonstrates the efficacy of piperonyl-butoxide (PBO) with deltamethrin, as pyrethroid insecticide, against the field-collected mosquitoe larvae of five species, Aedes aegypti, Anopheles culicifacies, An. stephensi, An. vagus, and Culex quinqufasciatus, and two morphological variants of Cx. tritaeniorhynchus (type A from grand pools of Mysore city and type B from rice fields of Mandya district). For testing the synergistic effect of PBO, stock solutions of deltamethrin and PBO were mixed in 1:6 ratio. The synergistic ratio and the percent suppression in deltamethrin tolerance were calculated by using LC(50) values. From the results, it is clear that, PBO is an effective synergist with deltamethrin against all of species undertaken in this investigation. So, it is suggested that PBO is a good synergist in this area for decreasing the use of pesticides in environment in vector control.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号