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   76篇
  免费   8篇
  2023年   1篇
  2022年   2篇
  2020年   4篇
  2018年   3篇
  2016年   3篇
  2014年   4篇
  2013年   5篇
  2012年   5篇
  2011年   2篇
  2010年   3篇
  2009年   3篇
  2008年   7篇
  2007年   6篇
  2006年   6篇
  2005年   4篇
  2004年   3篇
  2003年   5篇
  2002年   1篇
  2001年   1篇
  1999年   2篇
  1995年   1篇
  1994年   3篇
  1993年   2篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1979年   1篇
  1974年   1篇
  1959年   1篇
排序方式: 共有84条查询结果,搜索用时 15 毫秒
11.
A serially correlated gamma frailty model for longitudinal count data   总被引:3,自引:0,他引:3  
  相似文献   
12.
The I93M mutation in ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) was reported in one German family with autosomal dominant Parkinson's disease (PD). The causative role of the mutation has, however, been questioned. We generated transgenic (Tg) mice carrying human UCHL1 under control of the PDGF-B promoter; two independent lines were generated with the I93M mutation (a high- and low-expressing line) and one line with wild-type human UCH-L1. We found a significant reduction in the dopaminergic neurons in the substantia nigra and the dopamine content in the striatum in the high-expressing I93M Tg mice as compared with non-Tg mice at 20 weeks of age. Although these changes were absent in the low-expressing I93M Tg mice, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment profoundly reduced dopaminergic neurons in this line as compared with wild-type Tg or non-Tg mice. Abnormal neuropathologies were also observed, such as silver staining-positive argyrophilic grains in the perikarya of degenerating dopaminergic neurons, in I93M Tg mice. The midbrains of I93M Tg mice contained increased amounts of insoluble UCH-L1 as compared with those of non-Tg mice, perhaps resulting in a toxic gain of function. Collectively, our data represent in vivo evidence that expression of UCHL1(I93M) leads to the degeneration of dopaminergic neurons.  相似文献   
13.
Somatic mutations of the fibroblast growth factor receptor 3 (FGFR3) gene were detected by peptide nucleic acid (PNA)-mediated real-time PCR clamping. Mutation was detected in negative control containing only wild-type DNA due to a misincorporation of dNTPs to PNA binding sites when the amount of template DNA was decreased to 1 ng. Thus, the amount of template DNA was critical determinant of the assay sensitivity in PNA-mediated PCR clamping. Assay conditions were optimized to detect FGFR3 mutations in exons 7, 10, and 15, at a concentration of more than 1% mutated DNA using 50 ng of genomic DNA as the template. Mutations were detected in 12 of 13 (92.3%) tumor tissues and 11 of 13 (84.6%) urine samples from patients with superficial bladder cancer, while no mutations were detected in tissues and/or urine samples from patients with muscle-invasive bladder cancer or chronic cystitis.  相似文献   
14.
15.
Regulation of food intake by acyl and des-acyl ghrelins in the goldfish   总被引:2,自引:0,他引:2  
Our recent research has indicated that intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administration of n-octanoic acid-modified ghrelin (acyl ghrelin) stimulates food intake and locomotor activity in the goldfish. The manner in which peripherally administered acyl ghrelin regulates food intake, however, remains unclear. In contrast to acyl ghrelin, non-acylated ghrelin (des-acyl ghrelin) does not exert an orexigenic action or induce hypermotility. To this extent, the biological role of des-acyl ghrelin in fish is unknown. Given the possible involvement of afferent pathways in mediating the effects of acyl ghrelin, as is known to occur in rodents, we examined the effect of capsaicin, a neurotoxin which destroys primary sensory (vagal and splanchnic) afferents, on the orexigenic activity induced by i.p.-injected acyl ghrelin. Pretreatment with i.p.-injected capsaicin (0.16 micromol/g body weight (BW)) cancelled the orexigenic action of i.p.-injected acyl ghrelin (8 pmol/g BW), although i.p.-injected capsaicin alone did not affect food intake. The effect of des-acyl ghrelin on the orexigenic action of acyl ghrelin in the goldfish was also investigated. The i.c.v. and i.p. injection of des-acyl ghrelin at doses 3-10 times higher than that of acyl ghrelin suppressed the orexigenic action of i.c.v.- and i.p.-injected acyl ghrelin (doses of 1 and 8 pmol/g BW). In contrast, injection of des-acyl ghrelin alone did not show any inhibitory effect on food intake. These results suggest that, as is seen in rodents, circulating acyl ghrelin derived from peripheral tissues acts via primary sensory afferent pathways on feeding centers in the brain. The results also show that des-acyl ghrelin inhibits acyl ghrelin-induced orexigenic activity in goldfish.  相似文献   
16.

Background

In the early stages of Pandemic (H1N1) 2009, border control measures were taken by quarantine stations to block the entry of infected individuals into Japan and community containment measures were implemented to prevent the spreading. The objectives of this study were to describe these measures and the characteristics of infected individuals, and to assess the measures'' effectiveness.

Methodology/Principal Findings

Border control and community containment measures implemented from April to June (Period I: April 28–May 21, Period II: May 22–June 18) 2009 were described. Number of individuals identified and disease characteristics were analyzed. For entry screening, a health declaration form and an infrared thermoscanner were used to detect symptomatic passengers. Passengers indicated for the rapid influenza test underwent the test followed by RT-PCR. Patients positive for H1N1 were isolated, and close contacts were quarantined. Entry cards were handed out to all asymptomatic passengers informing them about how to contact a health center in case they developed symptoms. Nine individuals were identified by entry screening and 1 during quarantine to have Pandemic (H1N1) 2009. Health monitoring by health centers was performed in period I for passengers arriving from affected countries and in period II for those who had come into contact with the individuals identified by entry screening. Health monitoring identified 3 infected individuals among 129,546 in Period I and 5 among 746 in Period II. Enhanced surveillance, which included mandatory reporting of details of the infected individuals, identified 812 individuals, 141 (18%) of whom had a history of international travel. Twenty-four of these 141 passengers picked up by enhanced surveillance had been developing symptoms on entry and were missed at screening.

Conclusion/Significance

Symptomatic passengers were detected by the various entry screening measures put in place. Enhanced surveillance provided data for the improvement of public health measures in future pandemics.  相似文献   
17.
A wide variety of methods have been proposed to detect microbial activities, but most of them can be applied to limited categories of terrestrial organisms. We propose here to use phosphatase activity, which seems to be an essential catalytic activity for all the terrestrial organisms, and possibly for extraterrestrial organisms. We determined phosphatase activity in core samples, chimney samples, and sea water samples obtained in submarine hydrothermal systems located at Suiyo Seamount, Izu-Bonin Arc, and South Mariana. It was shown that phosphatase activity is one of possible biomarkers for extant life.  相似文献   
18.
19.
Regulation of food intake by melanin-concentrating hormone in goldfish   总被引:5,自引:4,他引:1  
Melanin-concentrating hormone (MCH), originally discovered in the teleost pituitary, is a hypothalamic neuropeptide involved in the regulation of body color in fish. Although MCH is also present in the mammalian brain, it has no evident function in providing pigmentation. Instead, this peptide is now recognized to be one of the key neuropeptides that act as appetite enhancers in mammals such as rodents and primates. Although there has been little information about the central action of MCH on appetite in fish, recent studies have indicated that, in goldfish, MCH acts as an anorexigenic neuropeptide, modulating the α-melanocyte-stimulating hormone signaling pathway through neuronal interaction. These observations indicate that there may be major differences in the mode of action of MCH between fish and mammals. This paper reviews what is currently known about the regulation of food intake by MCH in fish, especially the goldfish.  相似文献   
20.
Summary To assess the relationship between relatively severe hereditary hypercholesterolemia with Achilles tendon xanthomas and the defect of the low density lipoprotein (LDL) receptor gene, family studies were carried out in 17 hypercholesterolemic families. In 16 out of the 17 families, hypercholesterolemia co-segregated with four different gross rearrangements, six different restriction fragment length polymorphism (RFLP) haplotypes, or an abnormal TaqI band of the LDL receptor gene. These findings are compatible with the interpretation that hypercholesterolemia is caused by defective LDL receptor genes, and that the origin of the mutant LDL receptor genes in Japanese generally differs among different pedigrees. In the remaining family, the proband and his sibling, both having relatively severe hypercholesterolemia and Achilles tendon xanthomas, shared an RFLP haplotype, although the proband's other sibling with moderate hypercholesterolemia but without Achilles tendon xanthomas did not. The mutant gene for familial defective apolipoprotein B-100 was not detected in the 17 probands. These data suggest that most, if not all, of the relatively severe hereditary hypercholesterolemia associated with Achilles tendon xanthomas is caused by a defect of the LDL receptor gene.  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