全文获取类型
收费全文 | 5190篇 |
免费 | 393篇 |
国内免费 | 1篇 |
出版年
2023年 | 34篇 |
2022年 | 84篇 |
2021年 | 139篇 |
2020年 | 56篇 |
2019年 | 88篇 |
2018年 | 120篇 |
2017年 | 139篇 |
2016年 | 185篇 |
2015年 | 240篇 |
2014年 | 285篇 |
2013年 | 350篇 |
2012年 | 446篇 |
2011年 | 455篇 |
2010年 | 243篇 |
2009年 | 183篇 |
2008年 | 266篇 |
2007年 | 292篇 |
2006年 | 270篇 |
2005年 | 282篇 |
2004年 | 240篇 |
2003年 | 209篇 |
2002年 | 184篇 |
2001年 | 69篇 |
2000年 | 44篇 |
1999年 | 45篇 |
1998年 | 54篇 |
1997年 | 25篇 |
1996年 | 21篇 |
1995年 | 32篇 |
1994年 | 20篇 |
1993年 | 22篇 |
1992年 | 15篇 |
1991年 | 16篇 |
1990年 | 17篇 |
1989年 | 19篇 |
1988年 | 28篇 |
1987年 | 21篇 |
1986年 | 16篇 |
1985年 | 25篇 |
1984年 | 25篇 |
1983年 | 26篇 |
1982年 | 18篇 |
1981年 | 22篇 |
1977年 | 19篇 |
1976年 | 16篇 |
1975年 | 14篇 |
1972年 | 20篇 |
1971年 | 12篇 |
1969年 | 12篇 |
1968年 | 16篇 |
排序方式: 共有5584条查询结果,搜索用时 15 毫秒
101.
Collecting and storing biological material from wild animals in a way that does not deteriorate DNA quality for subsequent analyses is instrumental for research in ecology and evolution. Our aims were to gather reports on the effectiveness of methods commonly used by researchers for the field collection and long‐term storage of blood samples and DNA extracts from wild birds. Personal experiences were collected with an online survey targeted specifically at researchers sampling wild birds. Many researchers experienced problems with blood sample storage but not with DNA extract storage. Storage issues generated problems with obtaining adequate DNA quality and sufficient DNA quantity for the targeted molecular analyses but were not related to season of blood sampling, access to equipment, transporting samples, temperature, and method of blood storage. Final DNA quality and quantity were also not affected by storage time before DNA extraction or the methods used to extract DNA. We discuss practical aspects of field collection and storage and provide some general recommendations, with a list of pros and cons of different preservation methods of avian blood samples and DNA extracts. 相似文献
102.
Syukur Syukur Joanna Richmond Marwan E. Majzoub Jadranka Nappi Suhelen Egan Torsten Thomas 《Environmental microbiology》2024,26(1):e16564
Different marine seaweed species have been shown to harbour specific bacterial communities, however, the extent to which vertical symbiont transmission from parents to offspring contributes to host-specificity is unclear. Here we use fluorescence and electron microscopy as well as 16S rRNA gene-based community analysis to investigate symbiont transmission in members of the three major seaweed groups (green Chlorophyta, red Rhodophyta and brown Phaeophyceae). We found seaweeds employ diverse strategies to transfer symbionts to their progeny. For instance, the green Ulva australis does not appear to have the capacity for vertical transmission. In contrast, the brown Phyllospora comosa adopts a non-selective vertical transmission. The red Delisea pulchra demonstrates weak selectivity in symbiont transmission, while the brown Hormosira banksii exhibits a strongly selective symbiont transfer. Mucilage on the gametes appears to facilitate vertical transmission and transferred bacteria have predicted properties that could support early development of the seaweeds. Previous meta-analysis has indicated that vertical transmission is rare in aquatic compared to terrestrial environments, however, our results contribute to the growing evidence that this might not be the case and that instead vertical transmission with various degrees of symbiont selection occurs in the ecologically important group of seaweeds. 相似文献
103.
104.
105.
106.
107.
108.
109.
110.