全文获取类型
收费全文 | 709篇 |
免费 | 54篇 |
国内免费 | 55篇 |
出版年
2024年 | 2篇 |
2023年 | 19篇 |
2022年 | 48篇 |
2021年 | 65篇 |
2020年 | 54篇 |
2019年 | 44篇 |
2018年 | 49篇 |
2017年 | 22篇 |
2016年 | 33篇 |
2015年 | 55篇 |
2014年 | 36篇 |
2013年 | 44篇 |
2012年 | 48篇 |
2011年 | 48篇 |
2010年 | 22篇 |
2009年 | 32篇 |
2008年 | 29篇 |
2007年 | 18篇 |
2006年 | 21篇 |
2005年 | 16篇 |
2004年 | 13篇 |
2003年 | 10篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 12篇 |
1998年 | 2篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1985年 | 4篇 |
1982年 | 2篇 |
排序方式: 共有818条查询结果,搜索用时 15 毫秒
91.
92.
93.
Glycopeptide antibiotics are clinically important medicines to treat serious Gram-positive bacterial infections. The emergence of glycopeptide resistance among pathogens has motivated considerable interest in expanding structural diversity of glycopeptide to counteract resistance. The complex structure of glycopeptide poses substantial barriers to conventional chemical methods for structural modifications. By contrast, biochemical approaches have attracted great attention because ample biosynthetic information and sophisticated toolboxes have been made available to change reaction specificity through protein engineering, domain swapping, pathway engineering, addition of substrate analogs, and mutagenesis. 相似文献
94.
95.
Shuyang Xie Wei Li Zhaorui Ren Jingzhi Zhang Xinbin Guo Shu Wang Shuzhen Huang Fanyi Zeng Yi-Tao Zeng 《遗传学报》2008,35(10)
Large amounts of aberrantly spliced mRNA from the β654 allele was present in erythroid cells, which might impair the erythropoiesis.A therapeutic strategy for β-thalassemia was explored by knocking down the aberrantly spliced mRNA of β-globin. Lentiviral vector with siRNA fragment targets on the specific portion of β654-globin aberrantly spliced pre-mRNA was constructed. In HeLa β654 cells, the siRNA vector could reduce approximately 60% of aberrantly spliced mRNA, which was assessed by RT-PCR and qRT-PCR. Furthermore, a disease model of β654 thalassemia mice with lentiviral-mediated siRNA was produced by subzonal injection (named Hβi-Hbbth-4/Hbb+transgenic mice). Our results showed that the hemotological parameters were improved in Hβi-Hbbth-4/Hbb+ transgenic mice. This study provides a potential way for β654-thalassemia therapy by knocking down the aberrantly spliced β-globin mRNA, whilst supporting that the aberrantly spliced β-globin mRNA may aggravate the disease. 相似文献
96.
Jeong JB Kim HY Jun LJ Lyu JH Park NG Kim JK Jeong HD 《Diseases of aquatic organisms》2008,78(3):209-215
We examined the distribution of iridoviruses in 10 freshwater ornamental fish species hatched in Korea and imported from other Asian countries using both 1-step and 2-step polymerase chain reation (PCR). None of the 10 fish species analyzed were free of iridovirus as shown by 2-step PCR positive results, and 3 species yielded 1-step PCR positive results with associated mortality. Cloned PCR amplicons of the adenosine triphosphatase (ATPase) and major capsid protein (MCP) genes in genomic DNA of iridovirus showed the same nucleotide sequences as that of infectious spleen and kidney necrosis virus (ISKNV) isolated from the mandarinfish Siniperca chuatsi. These results indicate the presence of ISKNV disease in various ornamental fish as new host species and that the disease is widespread throughout different Asian countries including Korea, Singapore and China. Such infections were either clinical with associated mortality (and 1-step PCR positive) or asymptomatic in fish that were externally healthy (and only positive in 2-step PCR). Molecular analyses of the K2 region performed on iridovirus samples isolated from freshwater ornamental fishes revealed deletion/insertion of repetitive sequences of various lengths (42 to 339 bp), depending on the ISKNV isolates, without substitutions. Experimental infection of pearl gourami Trichogaster leeri and silver gourami T. microlepis with a tissue homogenate of pearl gourami infected by ISKNV induced 70 and 20% cumulative mortalities in the pearl and silver gourami, respectively. 相似文献
97.
98.
移植视网膜NOS阳性神经元的发育 总被引:2,自引:1,他引:1
目的 观察不同年龄组段大鼠正常视网膜及移植视网膜内NOS阳性神经元的发育情况及其定位分布。方法 实验分正常视网膜发育组和移植视网膜发育组,应用还原型烟酰胺腺嘌呤二核苷酸磷酸(NADPH)组织化学方法显示。结果 1、NOS阳性神经元最早出现于生后第五天(P5),P18时阳性神经元数目达到最高峰,2、移植视网膜具有正常视网膜的各层结构和相似的生长规律,NOS阳性神经元在生后第4天移植视网膜(TP4)中出现,TP12数量达到高峰值,TP22后降至正常成年鼠水平。结论 根据NOS阳性神经元的定位,分布,推测其为无长突细胞,移位无长突细胞及节细胞。 相似文献
99.
100.