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   275篇
  免费   29篇
  2021年   1篇
  2019年   2篇
  2018年   5篇
  2017年   2篇
  2016年   3篇
  2014年   4篇
  2013年   23篇
  2012年   18篇
  2011年   11篇
  2010年   8篇
  2009年   11篇
  2008年   18篇
  2007年   15篇
  2006年   22篇
  2005年   18篇
  2004年   19篇
  2003年   16篇
  2002年   22篇
  2001年   6篇
  2000年   5篇
  1999年   7篇
  1998年   4篇
  1997年   6篇
  1996年   10篇
  1995年   2篇
  1994年   4篇
  1993年   3篇
  1992年   6篇
  1991年   4篇
  1990年   7篇
  1989年   5篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1984年   2篇
  1982年   1篇
  1980年   1篇
  1978年   2篇
  1977年   2篇
  1974年   3篇
  1972年   1篇
  1970年   1篇
排序方式: 共有304条查询结果,搜索用时 78 毫秒
91.
We previously found that ANG II infusion into rats causes iron deposition in the kidney and heart, which may have a role in the regulation of profibrotic gene expression and tissue fibrosis. In the present study, we have investigated whether ANG II can also induce iron accumulation in the liver. Prussian blue staining detected frequent iron deposition in the interstitium of the liver of rats treated with pressor dose ANG II for 7 days, whereas iron deposition was absent in the livers of control rats. Immunohistochemical and histological analyses showed that some iron-positive nonparenchymal cells were positive for ferritin and heme oxygenase-1 (HO-1) protein and TGF-beta1 mRNA and were judged to be monocytes/macrophages. It was shown that ANG II infusion caused about a fourfold increase in ferritin and HO-1 protein expression by Western blot analysis and about a twofold increase in TGF-beta1 mRNA expression by Northern blot analysis, which were both suppressed by treating ANG II-infused rats with losartan and deferoxamine. In addition, mild interstitial fibrosis was observed in the liver of rats that had been treated with pressor dose ANG II for 7 days or with nonpressor dose ANG II for 30 days, the latter of which also caused loss of hepatocytes and intrahepatic hemorrhage in the liver. Taken together, our data suggest that ANG II infusion induces aberrant iron homeostasis in the liver, which may have a role in the ANG II-induced upregulation of profibrotic gene expression in the liver.  相似文献   
92.
Circulating smooth muscle progenitor cells contribute to atherosclerosis   总被引:20,自引:0,他引:20  
  相似文献   
93.
A series of N-substituted aryl and alkyl carbamates (RNHCOOR'; R: aryl, alkyl; R': aryl, alkyl) was prepared and screened for inhibitory activity toward the germination of oat seeds. The activity of each compound was compared with that of chlorpropham (isopropyl 3-chlorocarbanilate). Some of the synthetic carbamates possessing the N-(phenylthio)methyl group, PhSCH2NHCOOR', showed inhibitory activity close or comparable to that of chlorpropham.  相似文献   
94.

Background

Genetic polymorphisms in the human MDM2 gene are suggested to be a tumor susceptibility marker and a prognostic factor for cancer. It has been reported that a single nucleotide polymorphism (SNP) c.309T>G in the MDM2 gene attenuates the tumor suppressor activity of p53 and accelerates tumor formation in humans.

Methodology

In this study, to detect the SNP c.309T>G in the MDM2 gene, we have developed a new SNP detection method, named “Duplex SmartAmp,” which enabled us to simultaneously detect both 309T and 309G alleles in one tube. To develop this new method, we introduced new primers i.e., nBP and oBPs, as well as two different fluorescent dyes that separately detect those genetic polymorphisms.

Results and Conclusions

By the Duplex SmartAmp method, the genetic polymorphisms of the MDM2 gene were detected directly from a small amount of genomic DNA or blood samples. We used 96 genomic DNA and 24 blood samples to validate the Duplex SmartAmp by comparison with results of the conventional PCR-RFLP method; consequently, the Duplex SmartAmp results agreed totally with those of the PCR-RFLP method. Thus, the new SNP detection method is considered useful for detecting the SNP c.309T>G in the MDM2 gene so as to judge cancer susceptibility against some cellular stress in the clinical setting, and also to handle a large number of samples and enable rapid clinical diagnosis.  相似文献   
95.
(±)-trans-Allethrin-(Z)-ol (IV), (±)-trans-allethrin-(Z)-al (V) and (±)-trans-allethrin-(Z)-acid (VI), the minor components of allethrin metabolites in the insect body, were synthesized. The toxicities of newly synthesized allethrin derivatives (IV, V, VI) and of (±)-trans-allethrin-(E)-acid (Xc) to houseflies (Musca domestica L.) were examined by the injection method. And their low toxicities seem to support the hypothesis that oxidation at the isobutenyl side chain of the acid moiety of the allethrin molecule is a detoxication process in the insect body.  相似文献   
96.
A total synthesis of optically active pyriculol is described. The Wittig reaction between an aldehyde 19 and a triphenylphosphonium ylide 12 gave an intermediate 20. Successive treatment of 20 with p-toluenesulfonic acid, active manganese dioxide, and potassium carbonate gave (3′R,4′S)-pyriculol (23), which was identical with natural pyriculol (1) in all respects. From this synthesis, the absolute stereochemistry of pyriculol (1) was determined to be 2-[(3′R,4′S)-3′,4′-dihydroxy- (1′E,5′E)-1′,5′-heptadienyl]-6-hydroxybenzaldehyde  相似文献   
97.
In mice, the number of intestinal villous columnar epithelium cells that incorporate abnormal prion protein (PrP(Sc) ) decreases significantly after weaning. In this study, the dynamics of PrP(Sc) uptake during the growth of hamsters were investigated by inoculating scrapie 263K agent orally into suckling and weanling Syrian hamsters and estimating the number of PrP(Sc) -positive villous epithelium cells immunohistochemically. The number of PrP(Sc) -positive cells declined significantly as the hamsters aged. The present results suggest that a tendency toward decline of PrP(Sc) -positive cells with increasing age might be a common phenomenon among the superfamily Muridae.  相似文献   
98.
99.
Sumi M  Sata M  Toya N  Yanaga K  Ohki T  Nagai R 《Life sciences》2007,80(6):559-565
Therapeutic angiogenesis has emerged as a promising therapy to treat patients with ischemic diseases. Transplantation of bone marrow cells (BMCs) is reported to augment collateral development in ischemic organs either by differentiating into vascular cells or by secreting angiogenic cytokines. Recent evidence suggests that adipose tissues secrete a number of humoral factors and contain pluripotent stem cells. Here, we evaluated the therapeutic potential of adipose tissue-derived cells to promote angiogenesis in a mouse model of hind limb ischemia. Stromal vascular fraction cells (SVFs) were isolated from inguinal adipose tissue. Endothelial-like cells or smooth muscle-like cells could be obtained from the culture of SVFs in the presence of growth factors. Freshly isolated BMCs, SVFs, or mature adipocytes were transplanted into the ischemic hind limb of mice. SVFs significantly augmented collateral development as determined by the restoration of blood perfusion and capillary density of the ischemic muscle. Angiogenic effects of SVFs were as potent as those of BMCs. Mature adipocytes showed no proangiogenic effects. The ischemic muscle contained endothelial cells or smooth muscle cells that derived from the transplanted SVFs and BMCs. These results suggest that SVFs might be used to promote angiogenesis in ischemic tissues.  相似文献   
100.
Salmonella enterica serovar Typhimurium was isolated from the intestinal contents of Rattus rattus and Rattus norvegicus house rats captured at two buildings, designated buildings J and YS, in Yokohama City, Japan. From October 1997 to September 1998, 52 of 339 (15.3%) house rats were found to carry Salmonella serovar Typhimurium definitive phage type 104 (DT104). In building J, 26 of 161 (16.1%) house rats carried DT104 over the 1-year study period, compared to 26 of 178 (14.6%) rats in building YS. The isolation rates of DT104 from R. rattus and R. norvegicus were similar in the two buildings. Most DT104 strains from building J (24 of 26) showed resistance to ampicillin, chloramphenicol, streptomycin, sulfisoxazole, and tetracycline and contained both the 1.0- and 1.2-kbp integrons, carrying genes pse1, pasppflo-like, aadA2, sulI, and tet(G). All DT104 strains from building YS were resistant to ampicillin and sulfisoxazole, and had the 1.2-kbp integron carrying pse1 and sulI. Cluster analysis of pulsed-field gel electrophoresis patterns of BlnI-digested DT104 DNAs showed that 22 of 26 DT104 strains from building J and 24 of 26 strains from building YS could be grouped into separate clusters each specific for the building origin. These results indicated that DT104 strains were prevalent in house rat colonies in each building and suggest that house rats may play an important role in the epidemiology of DT104.  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