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   358篇
  免费   24篇
  国内免费   36篇
耳鼻咽喉   1篇
儿科学   1篇
妇产科学   1篇
基础医学   13篇
口腔科学   1篇
临床医学   11篇
内科学   11篇
神经病学   5篇
特种医学   2篇
外科学   12篇
综合类   77篇
预防医学   94篇
药学   83篇
中国医学   80篇
肿瘤学   26篇
  2024年   2篇
  2023年   4篇
  2022年   5篇
  2021年   6篇
  2020年   4篇
  2019年   6篇
  2018年   2篇
  2017年   6篇
  2016年   9篇
  2015年   16篇
  2014年   16篇
  2013年   32篇
  2012年   23篇
  2011年   33篇
  2010年   18篇
  2009年   34篇
  2008年   34篇
  2007年   34篇
  2006年   25篇
  2005年   33篇
  2004年   14篇
  2003年   26篇
  2002年   11篇
  2001年   8篇
  2000年   5篇
  1999年   3篇
  1998年   3篇
  1997年   3篇
  1996年   1篇
  1992年   1篇
  1991年   1篇
排序方式: 共有418条查询结果,搜索用时 15 毫秒
1.
怀槐愈伤组织形成与异黄酮积累   总被引:3,自引:0,他引:3  
目的 :考察怀槐愈伤组织形成与总异黄酮积累的关系。方法 :不同培养基诱导怀槐子叶和下胚轴产生愈伤组织 ,紫外分光光度术测定愈伤组织中总异黄酮并含量。结果 :NAA /BA及含 2 ,4-D组合有利子叶愈伤组织的诱导 ;MS ,N6 ,B5培养基适宜子叶形成愈伤组织 ,而SH较适宜下胚轴产生愈伤组织。愈伤组织具有异黄酮合成能力 ,含有NAA激素组合诱导的子叶愈伤组织总异黄酮含量较高 ,而 2 ,4-D/BA组合诱导的下胚轴愈伤组织总异黄酮含量较高 ,高浓度 2 ,4-D/KT组合抑制子叶和下胚轴愈伤组织积累异黄酮。愈伤组织根据发育的形态特征可分为 4种类型 ,以黄色、疏松、颗粒状的Ⅱ型愈伤组织中总异黄酮含量最高。结论 :培养基与激素组合影响愈伤组织的形成及发育形态特征 ,并反映在愈伤组织异黄酮合成差异上 ,获得的黄色、疏松颗粒状愈伤组织为后续的细胞液体悬浮培养及异黄酮合成代谢的调控研究奠定了基础。  相似文献   
2.
Data from epidemiological studies suggest that isoflavones in soy may have a protective effect on the development of colon cancer in humans. Therefore, we have investigated whether soy isoflavones will inhibit intestinal tumour development in ApcMin mice. The mice were fed a Western-type high risk diet (high fat, low fibre and calcium) containing two different isolates of soy protein as a protein source. For the control and test groups this resulted in the administration of about 16 and 475 mg of total isoflavones per kg diet, respectively. As a positive control, a third group of mice was administered a low isoflavone diet supplemented with 300 ppm sulindac. No significant differences in the incidence, multiplicity, size and distribution of intestinal tumours were observed between Min mice fed low and high isoflavone-containing diets. However, a clear reduction in the number of small intestinal tumours was observed for the sulindac diet. Thus, in contrast to epidemiological studies, our results demonstrate that high amounts of soy isoflavones present in a Western-type high risk diet do not protect against intestinal tumour development in a relevant animal model such as the Min mice.  相似文献   
3.
胶束毛细管电泳测定豆粕及发酵豆粕中大豆异黄酮含量   总被引:1,自引:0,他引:1  
 目的 建立测定豆粕及发酵豆粕中大豆异黄酮含量的毛细管电泳方法方法 采用胶束毛细管电泳法(MECC),未涂层弹性石英毛细管(50 μm×60 cm,50 cm);压力进样,压力:3.0×103 Pa;进样时间:5 s;分离电压:17 kV;柱温:20 ℃;检测波长:254 nm;运行缓冲液:15 mmol·L-1 十二烷基硫酸钠、5%甲醇的10 mmol·L-1硼砂溶液(pH 9.4)。结果 测得6种大豆异黄酮组分在24 min内能完全分离并具有良好的线性关系;平均加样回收率(n=5)在 99.6%~103.5%之间,RSD为1.8%~2.3%。结论 方法准确、可靠、经济、操作简便,适合于豆粕及发酵豆粕中大豆异黄酮含量的测定。  相似文献   
4.
合成了7-氯和-6-氯-7-甲氧基-3′-(N,N-二乙胺甲基)-4′-羟基异黄酮(1478和1481)。它们的合成是由间-氯苯酚或3-羟基-4-氯苯酚与对-硝基苯乙酰氯反应,制得取代的脱氧安息香。它们与原甲酸乙酯环合得到取代的-4′-硝基异黄酮,再将化合物中的硝基用锌粉还原成氨基,再经重氮化和水解,得到取代的-4′-羟基异黄酮。它们经Mannich反应,最后制得7-氯和6-氯-7-甲氧基-3′-(N,N-二乙胺甲基)-4′-羟基异黄酮。它们耐氧作用不如已合成的7-甲氧基-3′-(N,N-二烷胺甲基)-4′-羟基异黄酮。  相似文献   
5.
Aim: To investigate the effects of puerarin (Pue), an isoflavone derived from Kudzu roots, on angiotensin II (Ang II)-induced hypertrophy of cardiomyocytes in vivo and in vitro.
Methods: C57BL/6J mice were infused with Ang II and treated with Pue (100 mg·kg-1·d-1, po) for 15 d. After the treatment, systolic blood pressure (SBP) and left ventricular wall thickness were assessed. The ratios of heart weight to body weight (HW/BW) and left ventricular weight to body weight (LVW/BW) were determined, and heart morphometry was assessed. Expression of fetal-type genes (ANP, BNP and β-MHC) in left ventricles was measured using semi-quantitative RT-PCR. Mouse primary cardiomyocytes were treated with Pue (50, 100, 200 μmol/L), then exposed to Ang II (1 μmol/L). ROS level was examined with flow cytometry, the binding activity of NF-κB was determined using EMSA. Western blot was used to measure the levels of ERK1/2, p38 and NF-κB pathway proteins. [3H]leucine incorporation was used to measure the rate of protein synthesis.
Results: Oral administration of Pue significantly suppressed Ang II-induced increases in the myocyte surface area, HW/BW, LVW/BW, SBP and left ventricular wall thickness. Furthermore, Pue significantly suppressed Ang II-induced increases in ANP, BNP and β-MHC expression in the left ventricles in vivo. Treatment of cardiomyocytes with Pue (50–500 μmol/L) did not affect the viability of cardiomyocytes in vitro. Pretreatment of cardiomyocytes with Pue dose-dependently inhibited Ang II-induced increases in ROS production, NF-κB binding activity, protein synthesis and cell breadth. Furthermore, pretreatment with Pue significantly suppressed Ang II-induced activation of ERK1/2, p38 and the NF-κB pathway proteins and the expression of ANP and β-MHC in cardiomyocytes. The positive drug valsartan exerted similar effects on Ang II-induced cardiac hypertrophy in vivo and in vitro.
Conclusion: Pue attenuates Ang II-induced cardiac hypertrophy by inhibiting activation of the redox-sensitive ERK1/2, p38 and the NF-κB pathways.  相似文献   
6.
张加梅  褚新红  陈光芝 《齐鲁药事》2007,26(11):673-675
介绍近年来大豆异黄酮研究概况,包括大豆异黄酮的提取分离、含量测定、生理活性及其在体内的吸收代谢。  相似文献   
7.
目的 通过动物实验研究,观察B-cell lymphoma 2(Bcl-2)蛋白和Bcl-2-associated X protein(Bax蛋白)在大鼠卵巢组织中的表达情况。方法 选用2月龄Wistar雌性大鼠50只,按体重随机分成5组:空白对照组(基础饲料),大豆异黄酮低、中、高剂量组[含量分别为100、200、300 mg/(kg.bw)]、雌激素组(EC)(己烯雌酚0.5 mg/kg),实验周期为7周;采用酶联免疫吸附实验(ELISA)测定各组大鼠卵巢组织中Bcl-2蛋白和Bax蛋白水平。结果 空白对照组、大豆异黄酮低、中、高剂量组、雌激素组Bcl-2蛋白浓度分别为(1.41±0.19)、(1.43±0.20)、(2.07±0.58)、(2.42±0.32)、(2.95±0.78)pg/mL,组间差异均无统计学意义;Bax蛋白浓度分别为(33.64±5.83)、(30.02±9.44)、(17.33±4.21)、(9.67±1.95)、(10.69±4.95)pg/mL,其中大豆异黄酮高剂量组与空白对照组比较差异有统计学意义(P<0.05)。结论 大豆异黄酮可抑制大鼠Bax蛋白表达,对Bcl-2蛋白表达无影响。  相似文献   
8.
无花果果实中化学成分研究   总被引:1,自引:0,他引:1  
邵明辉  张文浩  张明明  刘艳萍  赵烽  付艳辉 《中草药》2019,50(11):2524-2528
目的研究桑科榕属植物无花果Ficus carica果实的化学成分。方法综合运用硅胶柱色谱、ODS柱色谱、Sephadex LH-20凝胶柱色谱以及制备型高效液相色谱等技术进行系统分离,根据化合物的理化性质及波谱数据鉴定化合物的化学结构。结果从无花果果实的90%乙醇提取物中分离得到了16个化合物,分别鉴定为怀特酮(1)、甘草宁G(2)、4′-羟基-5,7-二甲氧基-6-(3-甲基-丁烯基)-异黄酮(3)、猫尾草异黄酮(4)、indicanine C(5)、木豆素(6)、美迪紫檀素(7)、高丽槐素(8)、4-羟基-3-甲氧基-8,9-亚甲二氧基紫檀烷(9)、3-羟基-9,10-二甲氧基紫檀烷(10)、松脂素(11)、杜仲树脂酚(12)、丁香树脂醇(13)、8-羟基松脂醇(14)、3-羟基-1-(4-羟基-3-甲氧基苯)-1-丙酮(15)和4-羟基-3-甲氧基苯乙醇(16)。结论所有化合物均为首次从无花果中分离得到。  相似文献   
9.
This study investigated the relationship between headache and dietary consumption of a variety of nutrients in middle-aged women. This cross-sectional analysis used first-visit records of 405 women aged 40–59 years. The frequency of headaches was assessed using the Menopausal Health-Related Quality of Life Questionnaire. Of the 43 major nutrient intakes surveyed using the brief-type self-administered diet history questionnaire, those that were not shared between women with and without frequent headaches were selected. Multiple logistic regression analysis was used to identify nutrients independently associated with frequent headaches. After adjusting for background factors related to frequent headache (vasomotor, insomnia, anxiety, and depression symptoms), the estimated dietary intake of isoflavones (daidzein + genistein) (mg/1000 kcal/day) was negatively associated with frequent headaches (adjusted odds, 0.974; 95% confidence interval, 0.950–0.999). Moreover, the estimated isoflavone intake was not significantly associated with headache frequency in the premenopausal group, whereas it significantly correlated with that in the peri- and post-menopausal groups. Headache in peri- and post-menopausal women was inversely correlated with the dietary intake of isoflavones. Diets rich in isoflavones may improve headaches in middle-aged women.  相似文献   
10.
杨秀伟  张鹏 《中国现代中药》2023,25(5):1105-1112
妇科千金方是治疗妇科炎症性疾病的中药复方,已被认定为国家中药保护品种和国家基本药物目录品种,并已载入《中华人民共和国药典》 2020年版,分为妇科千金片和妇科千金胶囊2个品种。妇科千金方由千斤拔、金樱根、穿心莲、功劳木、单面针、鸡血藤、党参和当归8味中药组成。通过梳理妇科千金方的化学成分、质量控制、药动学和药理作用等相关文献并结合实际研究,基于“中药质量标志物理论”进行预测分析,小檗碱、巴马汀、药根碱、新穿心莲内酯苷、穿心莲内酯、新穿心莲内酯苷元、7-O-甲基汉黄芩素、染料木苷、芒柄花苷、染料木素、柚皮素、反式阿魏酸、水杨酸和Z-藁本内酯等专属性高、可测性强,可作为妇科千金方的潜在质量标志物,为其质量控制研究提供参考。  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