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   194篇
  免费   9篇
  国内免费   8篇
儿科学   1篇
基础医学   60篇
口腔科学   1篇
临床医学   27篇
内科学   16篇
皮肤病学   3篇
神经病学   21篇
特种医学   3篇
外科学   9篇
综合类   33篇
预防医学   3篇
眼科学   7篇
药学   16篇
中国医学   4篇
肿瘤学   7篇
  2022年   2篇
  2021年   4篇
  2020年   5篇
  2019年   3篇
  2018年   5篇
  2017年   4篇
  2016年   4篇
  2015年   4篇
  2014年   3篇
  2013年   19篇
  2012年   10篇
  2011年   8篇
  2010年   12篇
  2009年   13篇
  2008年   8篇
  2007年   11篇
  2006年   11篇
  2005年   10篇
  2004年   10篇
  2003年   10篇
  2002年   6篇
  2001年   10篇
  2000年   10篇
  1999年   5篇
  1998年   7篇
  1997年   5篇
  1996年   5篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   1篇
排序方式: 共有211条查询结果,搜索用时 15 毫秒
1.
Renal gene transfer techniques are being developed as a novelexperimental approach to understand the pathogenesis of renaldisease and to potentially develop new therapeutic tools. Wereview the currently available technology to introduce foreigngenetic material into renal tissue, i.e., retroviral, adenoviral,and liposomal transfer systems with their respective advantagesand caveats. Today, the transfer efficiency of these methodsappears to be sufficiently high to study the effects of transducedgenes on renal function and morphology in rat kidney. This willallow (i) the elucidation of the function of genes on the courseof renal disease in experimental animal models and (ii) themodulation of local expression of endogenous genes which presumptivelycontribute to renal pathology in these models. One strategyto accomplish this aim is the use of recombinant DNA technologyto design antisense DNA constructs or oligonucleotides, whichinterfere with the renal expression of target genes. We willalso discuss some of the shortcomings of the currently usedtechniques with respect to potential therapeutic use of genetransfer systems and gene modulation.  相似文献   
2.
N-Hydroxy-2-acetylaminofluorene (N-OH-AAF) is the proximate carcinogenic metabolite of the powerful rat liver carcinogen 2-acetylaminofluorene. In this study, transgenic Big Blue(R) rats were used to examine the relationship between in vivo mutagenicity and DNA adduct formation by N-OH-AAF in the target liver compared with that in nontarget tissues. Male rats were given one, two, or four doses of 25 mg N-OH-AAF/kg body weight by i.p. injection at 4-day intervals, and groups of treated and control rats were euthanized up to 10 weeks after beginning the dosing. Mutant frequencies were measured in the spleen lymphocyte hprt gene, and lacI mutant frequencies were determined in the liver and spleen lymphocytes. At 6 weeks after beginning the dosing, the hprt mutant frequency in spleen lymphocytes from the four-dose group was 16.5 x 10(-6) compared with 3.2 x 10(-6) in control animals. Also at 6 weeks, rats given one, two, or four doses of N-OH-AAF had lacI mutant frequencies in the liver of 97.6, 155.6, and 406.8 x 10(-6), respectively, compared with a control frequency of 25.7 x 10(-6); rats given four doses had lacI mutant frequencies in spleen lymphocytes of 55.8 x 10(-6) compared with a control frequency of 20.4 x 10(-6). Additional rats were evaluated for DNA adduct formation in the liver, spleen lymphocytes, and bone marrow by (32)P-postlabeling. Adduct analysis was conducted 1 day after one, two, and four treatments with N-OH-AAF, 5 days after one treatment, and 9 days after two treatments. N-(Deoxyguanosin-8-yl)-2-aminofluorene was the major DNA adduct identified in all the tissues examined. Adduct concentrations increased with total dose to maximum values in samples taken 1 day after two doses, and remained essentially the same after four doses. In samples taken after four doses, adduct levels were 103, 28, and 7 fmol/microg of DNA in liver, spleen lymphocytes, and bone marrow, respectively. The results indicate that the extent of both DNA adduct formation and mutant induction correlates with the organ specificity for N-OH-AAF carcinogenesis in the rat. Environ. Mol. Mutagen. 37:195-202, 2001. Published 2001 Wiley-Liss, Inc.  相似文献   
3.
口服转内皮抑素基因双歧杆菌制剂对肺癌的疗效   总被引:6,自引:1,他引:5  
目的:探讨转人内皮抑素基因双歧杆菌口服制剂对肺癌的治疗效果。方法:选择肺癌患者118例,比较服用转内皮抑素基因双歧杆菌口服制剂前后患者症状和体征,影像学检查(X线、CT,MRI),细胞学检查,纤维支气管镜检查及病理活检、免疫学检查(CEA)和生活质量等方面的变化。结果:服用转内皮抑素基因双歧杆菌口服制剂后患者症状和体征及生活质量等较服用前均有好转或明显好转,肺癌细胞生长被明显抑制。结论:转内皮抑素基因双歧杆菌口服制剂对肺癌有较好的治疗效果。  相似文献   
4.
Comparison of spontaneous mutation spectra derived from different transgenic constructs can provide valuable insights for interpreting the mechanisms of spontaneous mutation. In this study, spontaneous mutation frequencies and spectra of the lacI transgene are compared in the liver of C57BL/6, B6C3F1, and BC-1 mice and F344 rats. Before correction for clonal expansion, the mutant frequency varied from 2.6 +/- 0.45 to 5.0 +/- 2.4 x 10(-5). Correction for potential clonal expansion reduced the range in mutation frequency to between 2.3 +/- 0.45 and 3.5 +/- 2.0 x 10(-5). There is thus no statistical difference in spontaneous mutation frequency between the different strains and species. G:C --> A:T transitions and to a lesser extent, G:C --> T:A transversions dominate the mutational spectra in all of these animals. In three strains of mice, G:C --> A:T transitions account for 50.7-53.3% of mutation, 81.7-83.8% of which involve CpG sites, whereas G:C --> T:A transversions account for 17.8-32.9% of mutations with 43.2-50.0% found at CpG sites. In rats, G:C --> A:T transitions account for 38.0% of the spectra, 70.0% of which involve CpG sites, whereas G:C --> T:A transversions account for 23.0% of the spectra, 70.0% of which involve CpG sites. The distribution of other classes of mutations is also very similar. We conclude that, despite reports about species and strain differences in induced mutation, spontaneous mutations in the lacI transgene appear to be similar, regardless of genomic location, rodent strain, or species. In addition to insights into spontaneous mutation, this study also provides essential data for comparison with and interpretation of induced mutations.  相似文献   
5.
Three novel G-protein-coupled receptor genes related to the previously described RA1c gene have been isolated from the mouse genome. Expression of these genes has been detected in distinct areas of the brain and also in the olfactory epithelium of the nose. Developmental studies revealed a differential onset of expression: in the brain at embryonic stage 17, in the olfactory system at stage E12. In order to determine which cell type in the olfactory epithelium expresses this unique receptor type, a transgenic approach was employed which allowed a coexpression of histological markers together with the receptor and thus visualization of the appropriate cell population. It was found that the receptor-expressing cells were located very close to the basal membrane of the epithelium; however, the cells extended a dendritic process to the epithelial surface and their axons projected into the main olfactory bulb where they converged onto two or three glomeruli in the dorsal and posterior region of the bulb. Thus, these data provide evidence that this unique type of receptor is expressed in mature olfactory neurons and suggests that it may be involved in the detection of special odour molecules.  相似文献   
6.
目的 构建pUC18-α珠蛋白DNA-CD59cDNA重组分子。方法 采用人心肌组织作为RNA的来源,经RT-PCR扩增得到CD59基因的cDNA片段。以pUC18质粒为载体;人α-球蛋白DNA为启动子,并提供polyA+尾巴;以编码全部CD59蛋白质的核苷酸序列的cDNA作为目标基因,三者拼接成重组分子。结果 经酶切鉴定,重组分子拼接成功。结论 该重组分子可作为转基因构件,经微注射液入供体动物受  相似文献   
7.
目的 观察转bcl-2基因大鼠全脑缺血组再灌注后P-P38蛋白在海马回CA1区的表达. 方法 90只健康雄性SD大鼠,随机分为三组:假手术组(SO组,n=30),暴露血管而不夹闭;缺血再灌注组(IR组,n=30),采用4-VO法建立全脑缺血再灌注模型,5 min缺血后给予再灌注;转bcl-2基因组(bcl-2组,n=30):大鼠经转基因处理后再缺血再灌注.各组动物于再灌注后2,6,12,24,48,72 h处死,将脑组织切片进行HE染色,免疫组化染色及TUNEL染色,观察海马回神经元形态改变,凋亡细胞数量及P-P38在CA1区表达. 结果 HE染色显示:IR组全脑缺血再灌注后48 h CA1区神经元数目减少,排列紊乱,核膜界限不清,结构模糊;bcl-2组变化不明显.免疫组化染色显示:P-P38在SO组基本呈阴性着色;IR组CA1区2h出现,48 h达高峰,72 h略有下降;bcl-2组P-P38表达趋势同IR组,但各时间点表达强度弱于IR组.TUNEL染色显示:SO组可见到少量凋亡细胞;IR组全脑缺血再灌注后48 h凋亡细胞数达高峰;bcl-2组再灌注后12-72 h凋亡细胞数量较IR组均明显减少. 结论 全脑缺血再灌注后海马CA1区P-P38表达增加,bcl-2可通过抑制P-P38表达抑制脑缺血再灌注后的细胞凋亡.  相似文献   
8.
9.
10.
摘要: 目的 制作肝脏特异性高表达人胆固醇酯转移蛋白(CETP)转基因家兔并对其生物学特性分析进行分析。方法 利用显微注射方法制作CETP转基因家兔,利用Western Blot、Real-time PCR和CETP活性鉴定试剂盒鉴定模型家兔中人CETP转基因的表达和活性。结果 PCR检验结果显示我们成功获得CETP转基因家兔,转基因主要在肝脏特异性表达,其血浆CETP活性相对于非转基因家兔明显升高。结论 本研究首次成功建立了高表达人CETP的转基因家兔,为研究CETP功能和其参与心血管疾病的机制提供了良好模型。  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