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   362篇
  免费   39篇
  2020年   3篇
  2017年   3篇
  2016年   5篇
  2015年   8篇
  2014年   8篇
  2013年   10篇
  2012年   12篇
  2011年   17篇
  2010年   8篇
  2009年   10篇
  2008年   9篇
  2007年   17篇
  2006年   10篇
  2005年   12篇
  2004年   9篇
  2003年   7篇
  2002年   18篇
  2001年   25篇
  2000年   15篇
  1999年   9篇
  1998年   8篇
  1995年   5篇
  1993年   4篇
  1992年   7篇
  1991年   6篇
  1990年   6篇
  1989年   8篇
  1988年   5篇
  1987年   3篇
  1986年   7篇
  1985年   10篇
  1984年   5篇
  1983年   7篇
  1982年   8篇
  1981年   7篇
  1980年   3篇
  1979年   5篇
  1978年   6篇
  1977年   5篇
  1976年   3篇
  1974年   6篇
  1973年   5篇
  1972年   7篇
  1971年   4篇
  1970年   5篇
  1965年   3篇
  1946年   3篇
  1925年   2篇
  1915年   2篇
  1907年   2篇
排序方式: 共有401条查询结果,搜索用时 15 毫秒
71.

Background  

The aim of this study was to evaluate long-term platinum retention in patients treated with cisplatin and oxaliplatin.  相似文献   
72.
73.
74.
We examined changes in psychological distress experienced by residents of Christchurch following two catastrophic earthquakes in late 2010 and early 2011, using data from the New Zealand Attitudes and Values Study (NZAVS), a national probability panel study of New Zealand adults. Analyses focused on the 267 participants (172 women, 95 men) who were living in central Christchurch in 2009 (i.e., before the Christchurch earthquakes), and who also provided complete responses to our yearly panel questionnaire conducted in late 2010 (largely between the two major earthquakes), late 2011, and late 2012. Levels of psychological distress were similar across the different regions of central Christchurch immediately following the September 2010 earthquake, and remained comparable across regions in 2011. By late 2012, however, average levels of psychological distress in the regions had diverged as a function of the amount of property damage experienced within each given region. Specifically, participants in the least damaged region (i.e., the Fendalton-Waimairi and Riccarton-Wigram wards) experienced greater drops in psychological distress than did those in the moderately damaged region (i.e., across the Spreydon-Heathcote and Hagley-Ferrymead wards). However, the level of psychological distress reported by participants in the most damaged region (i.e., across Shirley-Papanui and Burwood-Pegasus) were not significantly different to those in the least damaged region of central Christchurch. These findings suggest that different patterns of psychological recovery emerged across the different regions of Christchurch, with the moderately damaged region faring the worst, but only after the initial shock of the destruction had passed.  相似文献   
75.
The epigenome plays a vital role in helping to maintain and regulate cell functions in all organisms. Alleles with differing epigenetic marks in the same nucleus do not function in isolation but can interact in trans to modify the epigenetic state of one or both alleles. This is particularly evident when two divergent epigenomes come together in a hybrid resulting in thousands of alterations to the methylome. These changes mainly involve the methylation patterns at one allele being changed to resemble the methylation patterns of the other allele, in processes we have termed trans-chromosomal methylation (TCM) and trans-chromosomal demethylation (TCdM). These processes are primarily modulated by siRNAs and the RNA directed DNA methylation pathway. Drawing from other examples of trans-allelic interactions, we describe the process of TCM and TCdM and the effect such changes can have on genome activity. Trans-allelic epigenetic interactions may be a common occurrence in many biological systems.  相似文献   
76.
Summary Using in situ hybridisation, we have localised the CD34 gene to chromosome 1 in the region q32.  相似文献   
77.
78.
Major osteological landmarks were used to prepare idealized drawings of mammalian and reptilian lower jaws. Measurements from these drawings allowed the average output or bite force, along the entire jaw, to be calculated for many different anteroposterior positions of the input or muscle force. In the mammalian drawing, the maximum average bite force is exerted when the resultant force is located at about 30% of the way along the jaw from the joints. Because of geometric differences in the reptilian drawing, a resultant positioned at 20% of the way along the jaw exerts the maximum average bite force; a maximum force that is smaller than that in the mammalian case. The estimated location of the muscle resultant in actual cases corresponds to these calculated positions. Therefore, in real animals, the muscles are located in the position that produces the largest average force for any jaw length. The geometric changes necessary to transform the idealized reptilian drawing, with a smaller maximum average bite force, into that of the mammalian drawing, with a larger maximum force, are the same as those changes seen in the fossil record of the reptile/mammal transition. This finding suggests that the morphological changes that occurred in the jaws increased the average bite force in the primitive mammals.  相似文献   
79.
We have previously described a developmentally regulated mRNA in maize that accumulates in mature embryos and is involved in a variety of stress responses in the plant. The sequence of the encoded 16 kDa protein (MA16) predicts that it is an RNA-binding protein, since it possesses a ribonucleoprotein consensus sequence-type RNA-binding domain (CS-RBD). To assess the predicted RNA binding property of the protein and as a starting point to characterize its function we have used ribohomopolymer-binding assays. Here we show that the MA16-encoded protein binds preferentially to uridine- and guanosine-rich RNAs. In light of these results a likely role for this protein in RNA metabolism during late embryogenesis and in the stress response is discussed.  相似文献   
80.
Chemoattractant arachidonate lipoxygenase products have been recovered from the skin lesions of psoriasis, and may play a role in eliciting the intra-epidermal neutrophil infiltrate that characterises this disease. In view of evidence for lipoxygenase activity in psoriasis, the characteristic vasolidation in psoriatic lesions, and the vasodilator properties of leukotriene (LT) C4 and D4 in human skin, the presence of these LTs in psoriatic lesions has been investigated. Skin chamber fluid from abraded psoriatic lesions contained significantly greater amounts of immunoreactive material than that from clinically normal skin, as determined by a double antibody radioimmunoassay (RIA) that uses antiserum cross-reacting with both LTC4 and LTD4. Purification of lesional chamber fluid and scale extracts by high performance liquid chromatography (HPLC) and RIA of fractions showed immunoreactivity which co-eluted with standard LTC4 and LTD4. These findings suggest that LTC4 and LTD4 may play a role in mediating the vasodilation and increased blood flow that characterise psoriatic skin lesions.  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