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   34篇
  国内免费   23篇
  2024年   1篇
  2023年   5篇
  2022年   4篇
  2021年   22篇
  2020年   8篇
  2019年   8篇
  2018年   13篇
  2017年   10篇
  2016年   9篇
  2015年   22篇
  2014年   11篇
  2013年   24篇
  2012年   18篇
  2011年   15篇
  2010年   14篇
  2009年   17篇
  2008年   16篇
  2007年   10篇
  2006年   22篇
  2005年   8篇
  2004年   8篇
  2003年   7篇
  2002年   10篇
  2001年   7篇
  2000年   9篇
  1999年   3篇
  1998年   4篇
  1997年   5篇
  1996年   2篇
  1995年   2篇
  1994年   3篇
  1993年   1篇
  1991年   2篇
  1990年   4篇
  1988年   1篇
  1987年   2篇
  1985年   2篇
  1979年   1篇
  1978年   1篇
  1974年   1篇
排序方式: 共有332条查询结果,搜索用时 31 毫秒
91.
Can Taste Aversion Prevent Bruxism?   总被引:2,自引:0,他引:2  
The first part of this note sketches a biofeedback modality for the treatment of bruxism. A mildly aversive, safe liquid is inserted into, and sealed in, small, bilaterally sleeved, polyethylene capsules. Two capsules are attached to a simple dental appliance that comfortably and securely places them between the lower and upper back teeth. The appliance and capsules are worn at night or at other times when bruxism is suspected to occur. Whenever a sleeping or an awake patient attempts to brux, one or both capsules rupture and the liquid is released into the mouth. The liquid then draws the patient's conscious attention to, and forestalls, any attempt of teeth clenching or grinding. Variations of the method and device can be used to diagnose bruxism. The second part of this note describes the long-term application of this taste-based approach to one chronic bruxer.  相似文献   
92.
93.
父母MTHFR基因型对后代发生神经管畸形的影响   总被引:9,自引:1,他引:8  
朱慧萍  李竹  刀京晶  赵欣荣  赵如冰 《遗传》2000,22(5):285-287
本研究旨在探讨父母双方MTHFR基因型与其后代发生神经管畸形风险性的关 系。采用成组匹配的病例对照研究方案,用纸片法采集病例和对照外周血标本,用PCR-RFLP方法确定基因型(C677T)。结果显示,分别比较两组父亲或母亲基因型频率时,差别不显著;将父母基因型联合起来分析则发现,病例组父母等位突变基因频率(T)高于对照组父母,提示后代是纯合突变( TT)概率越大,发生NTD的风险性也越大。结论是,父母双方的基因型对后代发生NTD的风险性有同等重要的作用,父母双方传递给胎儿的一对突变等位基因(T/T)是NTD发生的风险因素之一。 Abstract:The effect of parental MTHFR genotypes on fetal phenotype of NTD is studied.It was designed as group matched case-control study.Venous blood cases and controls were collected by dry blood spots.Genotype(C677T)of each sample was decided by PCR-RFLP method.When the genotypes of father and mother are compared separately,no significant difference is discovered between cases and controls.On the other hand,when the mutant allele frequency(T)is computed for father and mother together,it is significantly higher in cases than in controls.Higher probabilities of the offspring being homozygotes(TT),higher the risk for NTD occurrence has been observed.It is concluded that genotypes of MTHFR for both father and mother have the same impact on NTD occurrence of their offspring.It is the pair of mutant allele(T/T)which transmitted to the baby from its parents that increases the risk.  相似文献   
94.
Coronavirus disease, COVID-19 (coronavirus disease 2019), caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), has a higher case fatality rate in European countries than in others, especially East Asian ones. One potential explanation for this regional difference is the diversity of the viral infection efficiency. Here, we analyzed the allele frequencies of a nonsynonymous variant rs12329760 (V197M) in the TMPRSS2 gene, a key enzyme essential for viral infection and found a significant association between the COVID-19 case fatality rate and the V197M allele frequencies, using over 200,000 present-day and ancient genomic samples. East Asian countries have higher V197M allele frequencies than other regions, including European countries which correlates to their lower case fatality rates. Structural and energy calculation analysis of the V197M amino acid change showed that it destabilizes the TMPRSS2 protein, possibly negatively affecting its ACE2 and viral spike protein processing.  相似文献   
95.
《Free radical research》2013,47(6-7):498-506
Abstract

The etiologies of idiopathic sudden sensorineural hearing loss (SSNHL) and Ménière's disease remain unclear. Recently, accumulating evidence has demonstrated that free radicals are related to the pathology of inner ear disease. Because genetic factors may contribute partly to the etiologies of SSNHL and Ménière's disease, we investigated the association between genetic polymorphisms located in genes related to the free-radical process and susceptibility to SSNHL and Ménière's disease. We compared 83 patients affected by SSNHL and 83 patients affected by Ménière's disease with 2048 adults (for SSNHL) and 1946 adults (for Ménière's disease) who participated in the National Institute for Longevity Sciences, Longitudinal Study of Aging. Multiple logistic regression was used to calculate odds ratios (ORs) for SSNHL and Ménière's disease in individuals with polymorphisms in the genes: methionine synthase (MTR; rs1805087); methionine-synthase reductase (MTRR; rs1801394); nitric oxide synthase 3 (NOS3; rs1799983); caveolin 1 (Cav1; rs3840634); melatonin receptor 1B (MTNR1B; rs1387153); NAD(P)H oxidase p22(phox) subunit (NADH/NADPHp22phox; rs4673); and mitochondria 5178 (MT5178; rs28357984). The NOS3 polymorphism was significantly associated with a risk of SSNHL; in addition, the OR for the NOS3 polymorphism and SSNHL risk was 2.108 (CI, 1.343–3.309) with adjustment for age and sex. The Cav1 polymorphism was significantly associated with a risk of Ménière's disease; moreover, the OR for the Cav1 polymorphism and Ménière's disease risk was 1.849 (CI, 1.033–3.310) with adjustment for age and sex. In conclusion, the NOS3 and Cav1 polymorphisms were significantly associated with the risk of SSNHL and Ménière's disease, respectively.  相似文献   
96.
Population‐level analyses suggest that habitat complexity, but not necessarily space availability, has important welfare outcomes for elephants in human care. At the Dallas Zoo, the opening of a new exhibit complex allowed us to measure the behavior of two female African elephants across three treatments to evaluate the independent effects of complexity and space. Preoccupancy observations were conducted in the elephants’ older exhibit, which consisted of a smaller, more simple yard (630 m2). Subsequent postoccupancy observations measured behavior in two different spaces in the new exhibit: a larger, complex yard (15,000 m2), and a smaller, but complex yard (1,520 m2). The elephants’ overall activity levels were greater in complex habitats, regardless of their size. Similar effects of habitat complexity oversize were observed with greater rates of foraging and lower rates of being stationary. Furthermore, elephants were out of view of visitors significantly more in the small, simple yard compared to either of the more complex habitats. However, exhibit size affected the incidence of stereotypic behavior (with lower rates of stereotypy in the larger exhibit compared to the smaller yards) and investigatory behavior (elephants investigated their environments more with increasing size and complexity). Behavioral diversity also increased with exhibit size and complexity. These results indicate that space availability alone is not sufficient to enhance the behavioral welfare of zoo elephants. Therefore, facilities with limited space can still encourage species‐appropriate behaviors and improved welfare for the elephants in their care by converting a small, simple area into a more complex habitat.  相似文献   
97.
Background, Aims and Scope A strategy of local incineration with 17 small incinerators (Scenario L) is compared to a strategy of 3 centralized waste incinerators (Scenario C) for the region of Central Norway, in order to assess differences in environmental performance. Rough calculations of costs are also included. The functional unit is the treatment of municipal, commercial and special waste not recycled, plus the heating of a specific number of households, for the period of 2002 to 2020. Methods Data on large and small scale incinerators were obtained from technology providers. LCA databases were used for transportation and heating, while cost estimates and Norwegian input-output tables were used for the construction of the facilities. The CML2 method was used to evaluate the impacts. Results and Discussion Transportation is a major contributor to aquatic toxicity and acidification as well as CO2 emissions. Impacts from construction are considerable for photochemical oxidation, while incineration is important for terrestrial toxicity and CO2 emissions. Conclusion Construction and operation of treatment facilities are, together with transportation, the main processes making a difference between the two strategies. Substantial gains will come from the reduction in transportation need when introducing a local incineration strategy. When considering a time span of two decades, the centralized scenario is about 2.5 to 5 times the impact potential of the local scenario for most impact categories, in terms of cumulative results. Cost estimates for the two solutions support these findings, as cumulated costs also favors a local solution. Recommendation and Outlook Transportation is a major contributor to several impact categories, and especially the transportation of special waste should become more efficient in terms of transportation distances. Cost estimates support the environmental assessment, but a more comprehensive economic study of the system would be valuable.  相似文献   
98.

Background

Identification of the causative genes of retinitis pigmentosa (RP) is important for the clinical care of patients with RP. However, a comprehensive genetic study has not been performed in Korean RP patients. Moreover, the genetic heterogeneity found in sensorineural genetic disorders makes identification of pathogenic mutations challenging. Therefore, high throughput genetic testing using massively parallel sequencing is needed.

Results

Sixty-two Korean patients with nonsyndromic RP (46 patients from 18 families and 16 simplex cases) who consented to molecular genetic testing were recruited in this study and targeted exome sequencing was applied on 53 RP-related genes. Causal variants were characterised by selecting exonic and splicing variants, selecting variants with low allele frequency (below 1 %), and discarding the remaining variants with quality below 20. The variants were additionally confirmed by an inheritance pattern and cosegregation test of the families, and the rest of the variants were prioritised using in-silico prediction tools. Finally, causal variants were detected from 10 of 18 familial cases (55.5 %) and 7 of 16 simplex cases (43.7 %) in total. Novel variants were detected in 13 of 20 (65 %) candidate variants. Compound heterozygous variants were found in four of 7 simplex cases.

Conclusion

Panel-based targeted re-sequencing can be used as an effective molecular diagnostic tool for RP.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1723-x) contains supplementary material, which is available to authorized users.  相似文献   
99.
中国援利埃博拉诊疗中心在执行埃博拉收治任务时,积极对接利国疫情防控体系,建设实践了一套病例调查与接触追踪上报体系,包括建立体系组织架构、完善调查上报制度、构建数据链信息平台、建立内部核查机制,其准确性和及时性得到了广泛赞誉。通过实践,我们认为,建立病例调查和接触追踪机制,是传染病疫情控制的关键,未来应不断探索与国际接轨的机制、拓展应用信息化技术,并始终做到持续改进。  相似文献   
100.
目的 建立主诊医师负责制下的住院绩效分配新模式,以适应医药分开改革的新要求。方法 探索基于医疗成果产出的岗位绩效管理考核和分配新制度,重点激励各主诊医师组医疗产出的工作量和工作难度,促使各主诊医师组增加服务量、提高技术水平和诊治疾病的难度。结果 以某科室各主诊医师组为例,从科室管理、团队建设、学科发展、工作效率等角度分析医改前后转变。结论 重点激励分配制度,逐步被医务人员所接受,并取得较为明显的成效。  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