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   240篇
  免费   11篇
  国内免费   3篇
儿科学   1篇
基础医学   20篇
口腔科学   1篇
临床医学   11篇
内科学   8篇
神经病学   11篇
特种医学   9篇
外科学   5篇
综合类   47篇
预防医学   30篇
药学   62篇
中国医学   43篇
肿瘤学   6篇
  2023年   1篇
  2022年   2篇
  2021年   4篇
  2020年   3篇
  2019年   1篇
  2018年   3篇
  2017年   7篇
  2016年   14篇
  2015年   5篇
  2014年   21篇
  2013年   27篇
  2012年   25篇
  2011年   26篇
  2010年   16篇
  2009年   13篇
  2008年   12篇
  2007年   7篇
  2006年   9篇
  2005年   3篇
  2004年   5篇
  2003年   9篇
  2002年   4篇
  2001年   1篇
  2000年   3篇
  1999年   3篇
  1998年   4篇
  1997年   3篇
  1995年   4篇
  1994年   3篇
  1992年   2篇
  1991年   1篇
  1982年   1篇
  1974年   2篇
  1973年   3篇
  1972年   1篇
  1971年   2篇
  1970年   1篇
  1969年   3篇
排序方式: 共有254条查询结果,搜索用时 62 毫秒
1.
研究了LDPE/CPE/炭黑三相复合导电体系的导性能和电流-电压特性。实验结果表明复合体系具有明显的导电渗滤效应,在共混比LDPE/CPE>50/50时,导电性能随CPE含量增加而显著提高,这主要是由于炭黑粒子在LDPE和CPE两组分分中的分布不均匀性所致。  相似文献   
2.
本文采用荧光素钠正常鼠脑悬液做模拟示踪物质,对肾综合征出血热病毒气溶胶在空气中的物理稳定性进行了测定,并与其生物稳定性做了比较。结果表明:病毒气溶胶的粒子大小在1um左右,它随气溶胶的胶龄增长而减少,且其分散度变窄。初始气溶胶的物理回收率及其各胶龄的物理存留率均明显地高于它的生物回收率和生物存活率。本文还就肾综合征出血热病毒气溶胶的物理稳定性和生物稳定性,对本病空气传播的影响进行了讨论。  相似文献   
3.
Lack of efficient culture systems for hepatitis C virus (HCV) has been a major obstacle in HCV research. Human liver cells grown in a three-dimensional radial-flow bioreactor were successfully infected following inoculation with plasma from an HCV carrier. Subsequent detection of increased HCV RNA suggested viral replication. Furthermore, transfection of HCV RNA transcribed from full-length cDNA also resulted in the production and release of HCV virions into supernatant. Infectivity was shown by successful secondary passage to a new culture. Introduction of mutations in RNA helicase and polymerase regions of HCV cDNA abolished virus replication, indicating that reverse genetics of this system is possible. The ability to replicate and detect the extracellular release of HCV might provide clues with regard to the persistent nature of HCV infection. It will also accelerate research into the pathogenicity of HCV, as well as the development of prophylactic agents and new therapy.  相似文献   
4.
CT引导下经皮穿刺种植放射性125I粒子治疗晚期肺癌   总被引:41,自引:0,他引:41  
目的 探讨应用肿瘤组织间三维立体定向放射治疗计划系统 (TPS)、CT引导下经皮穿刺种植放射性12 5I粒子治疗晚期非小细胞肺癌及并发症处理方法。方法 随机选择 5 3例术前活检证实为非小细胞肺癌患者 ,应用TPS计算出放射源—12 5I粒子在瘤灶区的剂量分布 ,绘出等剂量曲线及适形粒子分布图并制定治疗计划 ,通过CT引导经皮穿刺种植12 5I粒子。术后即刻CT扫描验证 ,术后2个月复查CT检查肿瘤情况。结果 植入粒子后 ,瘤体接受的平均照射剂量为 15 0 .5Gy ,mPD84 .6Gy,D90 92 .4Gy,D90 >mPD。 2例需要立即补种粒子。术后 2个月复查的 37例患者 ,胸CT显示完全缓解 10例 ,部分缓解 2 7例。并发症包括术中气胸 19例 ,咳血 7例 ,术后发烧 5例 ,4例粒子移位 ,2例游走。结论 TPS立体定向CT引导下经皮穿刺种植放射性12 5I粒子是一种有效的、微创的治疗晚期非小细胞肺癌的方法  相似文献   
5.
Amorphous silica nanoparticles (SiNPs) have previously been shown to induce marked cytokine (interleukin-6; IL-6 and interleukin-8; CXCL8/IL-8) responses independently of particle uptake in human bronchial epithelial BEAS-2B cells. In this study the involvement of the mitogen-activated protein kinases (MAP-kinases), nuclear factor-kappa Β (NF-κΒ) and in particular tumour necrosis factor-α converting enzyme (TACE) and—epidermal growth factor receptor (EGFR) signalling pathways were examined in triggering of IL-6 and CXCL8 release after exposure to a 50 nm silica nanoparticle (Si50). Exposure to Si50 increased phosphorylation of NF-κΒ p65 and MAP-kinases p38 and JUN-N-terminal protein kinase pathways (JNK), but not extracellular signal regulated kinases (ERK). Inhibition of NF-κΒ and p38 reduced the cytokine responses to Si50, whereas neither JNK- nor ERK-inhibition exerted any significant effect on the responses to Si50. Increases in membrane-bound transforming growth factor-α (TGF-α) release and EGFR phosphorylation were also observed after Si50 exposure, and pre-treatment with inhibitors of these pathways reduced the release of IL-6 and CXCL8, but did not affect the Si50-induced phosphorylation of p38 and p65. In contrast, p38-inhibition partially reduced Si50-induced TGF-α release, while the p65-inhibition was without effect. Overall, our results indicate that Si50-induced IL-6 and CXCL8 responses in BEAS-2B cells were regulated through combined activation of several pathways, including NF-κΒ and p38/TACE/TGF-α/EGFR signalling. The study identifies critical, initial events in the triggering of pro-inflammatory responses by nanoparticles.  相似文献   
6.
Data generated using standardized testing protocols for toxicity studies generally provide reproducible and reliable results for establishing safe levels and formulating risk assessments. The findings of three OECD guideline-type oral toxicity studies of different duration in rats are summarized in this publication; each study evaluated different titanium dioxide (TiO2) particles of varying sizes and surface coatings. Moreover, each study finding demonstrated an absence of any TiO2 -related hazards. To briefly summarize the findings: 1) In a subchronic 90-day study (OECD TG 408), groups of young adult male and female rats were dosed with rutile-type, surface-coated pigment-grade TiO2 test particles (d50 = 145 nm − 21% nanoparticles by particle number criteria) by oral gavage for 90 days. The no-adverse-effect level (NOAEL) for both male and female rats in this study was 1000 mg/kg bw/day, the highest dose tested. The NOAEL was determined based on a lack of TiO2 particle-related adverse effects on any in-life, clinical pathology, or anatomic/microscopic pathology parameters; 2) In a 28-day repeated-dose oral toxicity study (OECD TG 407), groups of young adult male rats were administered daily doses of two rutile-type, uncoated, pigment-grade TiO2 test particles (d50 = 173 nm by number) by daily oral gavage at a dose of 24,000 mg/kg bw/day. There were no adverse effects measured during or following the end of the exposure period; and the NOAEL was determined to be 24,000 mg/kg bw/day; 3) In an acute oral toxicity study (OECD TG 425), female rats were administered a single oral exposure of surface-treated rutile/anatase nanoscale TiO2 particles (d50 = 73 nm by number) with doses up to 5000 mg/kg and evaluated over a 14-day post-exposure period. Under the conditions of this study, the oral LD50 for the test substance was >5000 mg/kg bw. In summary, the results from these three toxicity studies – each with different TiO2 particulate-types, demonstrated an absence of adverse toxicological effects. Apart from reporting the findings of these three studies, this publication also focuses on additional critical issues associated with particle and nanotoxicology studies. First, describing the detailed methodology requirements and rigor upon which the standardized OECD 408 guideline subchronic oral toxicity studies are conducted. Moreover, an attempt is made to reconcile the complex issue of particle size distribution as it relates to measurements of nanoscale and pigment-grade TiO2 particles. Clearly this has been a confusing issue and often misrepresented in the media and the scientific literature. It is clear that the particle-size distribution for pigment-grade TiO2, contains a small (“tail”) component of nanoscale particles (i.e., 21% by particle number and <1% by weight in the test material used in the 90-day study). However, this robust particle characterization finding should not be confused with mislabeling the test materials as exclusively in the nanoscale range. Moreover, based upon the findings presented herein, there appears to be no significant oral toxicity impact contributed by the nanoscale component of the TiO2 Test Material sample in the 90-day study. Finally, it seems reasonable to conclude that the study findings should be considered for read-across purposes to food-grade TiO2 particles (e.g., E171), as the physicochemical characteristics are quite similar.  相似文献   
7.
目的:建立脑脉利颗粒中芍药苷,益母草碱,黄芪甲苷及盐酸水苏碱的含量测定方法。方法:采用甲醇、酸水等不同的溶剂提取,并采用高效液相色谱法,液质联用法等灵敏、专属的色谱方法进行含量测定。结果:每10g脑脉利颗粒中含有芍药苷 42.41 mg,益母草碱 1.73mg,黄芪甲苷 0.10 mg,盐酸水苏碱 37.98mg。结论:制剂中其他组分与所测定的各组分分离良好,不干扰测定,可用于脑脉利颗粒中芍药苷,益母草碱,黄芪甲苷及盐酸水苏碱的含量测定。  相似文献   
8.
目的 探讨女珍颗粒联合佐匹克隆片治疗更年期失眠症的临床疗效。方法 选取2016年3月—2018年10月在内蒙古自治区精神卫生中心进行治疗的82例更年期失眠患者为研究对象,根据用药的差别分为观察组(41例)和对照组(41例)。对照组给予佐匹克隆片,7.5 mg/次,1次/d,睡前服用;观察组在对照组基础上口服女珍颗粒,6 g/次,3次/d。两组均治疗4周后进行效果对比。结果 经治疗,对照组有效率为82.92%,显著低于治疗组95.12%(P<0.05)。经治疗,两组患者匹兹堡睡眠质量指数量表(PSQI)评分降低;多导睡眠监测(PSG)中入睡时间、觉醒时间降低,总睡眠时间增加,睡眠效率提高;睡眠结构中I期时间缩短,II、III期及快速动眼期时间延长(P<0.05),且观察组睡眠情况显著优于对照组(P<0.05)。经治疗,两组患者血清中神经递质去甲肾上腺素(NE)、5-羟色胺(5-HT)、多巴胺(DA)水平显著升高(P<0.05),且观察组神经递质水平显著高于对照组(P<0.05)。经治疗,两组焦虑自评量表评分(SAS)、抑郁自评量表评分(SDS)、SCL-90、Hamilton抑郁量表(HAMD)评分均显著降低(P<0.05),且观察组上述评分显著低于对照组(P<0.05)。结论 女珍颗粒联合佐匹克隆片治疗更年期失眠症效果良好,可有效减轻失眠症状,改善患者负面情绪,提高患者生活质量,有着良好临床应用价值。  相似文献   
9.
目的 研究小儿肺热咳喘颗粒(XFKP)清热解毒、止咳平喘作用。方法 采用牛奶致热家兔模型观察XFKP的解热作用;制备脂多糖(LPS)肺炎小鼠模型,观察XFKP对支气管肺泡灌洗液中超氧化物歧化酶(SOD)、髓过氧化物酶(MPO)活性及炎症细胞的积聚的影响;采用小鼠氨水、豚鼠磷酸组胺诱咳引喘模型,观察XFKP的止咳平喘作用。结果 与对照组比较,高、中剂量XFKP能够显著降低发热家兔体温(P<0.05);高、中剂量XFKP明显降低肺炎模型小鼠肺内积水量和肺泡中白细胞总数、淋巴细胞数,且高剂量组能显著抑制MPO活性(P<0.05、0.01);高、中剂量XFKP组能够显著地延长小鼠咳嗽潜伏期,减少咳嗽次数,延长豚鼠引喘潜伏期(P<0.05、0.01)。结论 小儿肺热咳喘颗粒具有显著的清热解毒、止咳平喘作用。  相似文献   
10.
目的:建立疏络化纤颗粒的质量控制方法。方法:对制剂中的百合、灵芝、茜草、地龙、丹参采用薄层色谱(TLC)法进行定性鉴别;采用高效液相色谱(HPLC)法对制剂中的疏络化纤颗粒所含成分芍药苷进行含量测定,以C18柱为色谱柱,乙腈-0.1%磷酸水溶液(1486)为流动相,检测波长为230 nm。结果:用薄层鉴别百合、灵芝具有较好的专属性;在0.313~0.626μg范围内芍药苷与峰面积呈良好的线性关系,r2=0.9999,回收率均在95%与105%之间,RSD小于5%(n=6)。结论:所建立的方法专属性强,简便准确,该制剂标准可有效控制其质量。  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