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   5266篇
  免费   183篇
  国内免费   2篇
  2023年   129篇
  2020年   52篇
  2019年   53篇
  2018年   46篇
  2017年   46篇
  2016年   67篇
  2015年   126篇
  2014年   147篇
  2013年   533篇
  2012年   229篇
  2011年   185篇
  2010年   139篇
  2009年   121篇
  2008年   147篇
  2007年   166篇
  2006年   120篇
  2005年   119篇
  2004年   85篇
  2003年   81篇
  2002年   99篇
  1999年   56篇
  1998年   48篇
  1997年   58篇
  1996年   45篇
  1995年   41篇
  1994年   34篇
  1993年   47篇
  1992年   36篇
  1989年   76篇
  1988年   69篇
  1987年   99篇
  1986年   57篇
  1985年   58篇
  1984年   58篇
  1983年   39篇
  1982年   55篇
  1981年   54篇
  1980年   62篇
  1979年   63篇
  1978年   65篇
  1977年   67篇
  1976年   87篇
  1975年   80篇
  1974年   60篇
  1973年   35篇
  1972年   40篇
  1971年   29篇
  1964年   40篇
  1958年   37篇
  1957年   32篇
排序方式: 共有5451条查询结果,搜索用时 15 毫秒
1.
The recent identification of VKORC1 has made important contributions to our understanding of the vitamin K cycle. The VKORC1 enzyme was shown to be the molecular target of coumarin drugs. Mutations and polymorphisms in coding and noncoding regions of the VKORC1 gene have been shown to cause both a partial to total coumarin resistance and coumarin sensitivity. Availability of molecular diagnostics (VKORC1, CYP2C9) and drug monitoring by HCPLC (determination of coumarin, vitamin K, and vitamin K epoxide levels) is helpful for detecting hereditary and acquired factors influencing coumarin therapy. In the future, these tools may be instrumental in designing individualized oral anticoagulation therapy regimens.  相似文献   
2.
Nutrition plays a key role in many aspects of health and dietary imbalances are major determinants of chronic diseases including cardiovascular disease, obesity, diabetes and cancer. Adequate nutrition is particularly essential during critical periods in early life (both pre- and postnatal). In this regard, there is extensive epidemiologic and experimental data showing that early sub-optimal nutrition can have health consequences several decades later.  相似文献   
3.
4.
Bench testing is a useful method to characterize the response of different automatic positive airway pressure (APAP) devices under well-controlled conditions. However, previous models did not consider the diversity of obstructive sleep apnea (OSA) patients’ characteristics and phenotypes. The objective of this proof-of-concept study was to design a new bench test for realistically simulating an OSA patient’s night, and to implement a one-night example of a typical female phenotype for comparing responses to several currently-available APAP devices. We developed a novel approach aimed at replicating a typical night of sleep which includes different disturbed breathing events, disease severities, sleep/wake phases, body postures and respiratory artefacts. The simulated female OSA patient example that we implemented included periods of wake, light sleep and deep sleep with positional changes and was connected to ten different APAP devices. Flow and pressure readings were recorded; each device was tested twice. The new approach for simulating female OSA patients effectively combined a wide variety of disturbed breathing patterns to mimic the response of a predefined patient type. There were marked differences in response between devices; only three were able to overcome flow limitation to normalize breathing, and only five devices were associated with a residual apnea-hypopnea index of <5/h. In conclusion, bench tests can be designed to simulate specific patient characteristics, and typical stages of sleep, body position, and wake. Each APAP device behaved differently when exposed to this controlled model of a female OSA patient, and should lead to further understanding of OSA treatment.  相似文献   
5.
6.
7.
8.
It has long been debated whether the mind consists of specialized and independently evolving modules, or whether and to what extent a general factor accounts for the variance in performance across different cognitive domains. In this study, we used a hierarchical Bayesian model to re-analyse individual level data collected on seven primate species (chimpanzees, bonobos, orangutans, gorillas, spider monkeys, brown capuchin monkeys and long-tailed macaques) across 17 tasks within four domains (inhibition, memory, transposition and support). Our modelling approach evidenced the existence of both a domain-specific factor and a species factor, each accounting for the same amount (17%) of the observed variance. In contrast, inter-individual differences played a minimal role. These results support the hypothesis that the mind of primates is (at least partially) modular, with domain-specific cognitive skills undergoing different evolutionary pressures in different species in response to specific ecological and social demands.  相似文献   
9.
10.
Therapeutic use of stem cells Here the hematopoetic system of blood‐ and immune cell renewal is reviewed. Curing of chronic leucemias and malignant lymphomas is the most successful stem cell based therapy up to date. However, mismatches of histocompatibility‐complexes (HLA‐types) between receiver and donor set narrow limits to such therapies. Whether other diseases such as Parkinson could be cured by infusion of stem cells is still in question.  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