全文获取类型
收费全文 | 97168篇 |
免费 | 635篇 |
国内免费 | 883篇 |
专业分类
98686篇 |
出版年
2022年 | 45篇 |
2021年 | 78篇 |
2020年 | 55篇 |
2019年 | 56篇 |
2018年 | 11879篇 |
2017年 | 10704篇 |
2016年 | 7534篇 |
2015年 | 737篇 |
2014年 | 470篇 |
2013年 | 513篇 |
2012年 | 4531篇 |
2011年 | 13123篇 |
2010年 | 12164篇 |
2009年 | 8412篇 |
2008年 | 10032篇 |
2007年 | 11562篇 |
2006年 | 459篇 |
2005年 | 736篇 |
2004年 | 1181篇 |
2003年 | 1224篇 |
2002年 | 977篇 |
2001年 | 300篇 |
2000年 | 200篇 |
1999年 | 64篇 |
1998年 | 52篇 |
1997年 | 53篇 |
1996年 | 40篇 |
1995年 | 33篇 |
1994年 | 48篇 |
1993年 | 58篇 |
1992年 | 54篇 |
1991年 | 60篇 |
1990年 | 31篇 |
1989年 | 32篇 |
1988年 | 42篇 |
1987年 | 34篇 |
1985年 | 24篇 |
1984年 | 45篇 |
1983年 | 43篇 |
1982年 | 28篇 |
1980年 | 37篇 |
1979年 | 21篇 |
1978年 | 36篇 |
1977年 | 33篇 |
1975年 | 27篇 |
1974年 | 24篇 |
1973年 | 23篇 |
1972年 | 257篇 |
1971年 | 285篇 |
1962年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
151.
Paola A Gilardoni Stefan Schuck Ruth Jüngling Björn Rotter Ian T Baldwin Gustavo Bonaventure 《BMC plant biology》2010,10(1):66
Background
Plants trigger and tailor defense responses after perception of the oral secretions (OS) of attacking specialist lepidopteran larvae. Fatty acid-amino acid conjugates (FACs) in the OS of the Manduca sexta larvae are necessary and sufficient to elicit the herbivory-specific responses in Nicotiana attenuata, an annual wild tobacco species. How FACs are perceived and activate signal transduction mechanisms is unknown. 相似文献152.
Eduardo León-Ruiz Purificación Alcázar Eugenio Domínguez-Vilches Carmen Galán 《Aerobiologia》2011,27(1):37-50
The present study sought to determine which of the common Poaceae species in the study area contribute most to the Poaceae
pollen season curve, and to determine the phenological behaviour of the species studied. The different floral phenophases
in thirty-three Poaceae species common in and around the city of Córdoba (SW Iberian Peninsula) were checked periodically
over the period 2004–2006. Results showed that longer phenological ranges were recorded in the coolest and wettest year, and
shorter ranges in the warmest and driest year. Moreover, ranges varied as a function of altitude: populations in lower-lying
areas flowered earlier than those at higher altitudes. The results, taken in conjunction with the findings of preliminary
research into potential pollen production, showed that probably only four of the Poaceae species studied—Dactylis glomerata, Lolium rigidum, Trisetaria panicea and Vulpia geniculata—were major contributors to the Poaceae airborne pollen curve. 相似文献
153.
Taxonomic distribution and origins of the extended LHC (light-harvesting complex) antenna protein superfamily 总被引:1,自引:0,他引:1
Background
The extended light-harvesting complex (LHC) protein superfamily is a centerpiece of eukaryotic photosynthesis, comprising the LHC family and several families involved in photoprotection, like the LHC-like and the photosystem II subunit S (PSBS). The evolution of this complex superfamily has long remained elusive, partially due to previously missing families. 相似文献154.
155.
156.
Yan-Hong He Guo-Gui Ning Ya-Lin Sun Yan Hu Xing-Yu Zhao Man-Zhu Bao 《Molecular breeding : new strategies in plant improvement》2010,26(1):19-29
A male sterile line was isolated in marigold (Tagetes erecta L.) and cytological analysis determined this to be a novel genic male sterility trait (Tems). Through the use of amplified fragment length polymorphisms (AFLPs) and bulked segregant analysis (BSA), tightly linked
markers of Tems were identified with a view towards a map-based cloning strategy. It was found that spontaneous homeotic conversion of floral
organs was the underlying cause of the male sterility in this marigold line. Thus, petals of male sterile plants resembled
sepal-like structures and the stamens were partially converted to styles, although without the full characteristics or function
of the true style organs. We have constructed a fine marker-based map for the Tems gene. This is intended to provide a tool for marker assisted selection (MAS) strategies in hybrid breeding and map-based
cloning strategies for the male sterility locus. We discuss the significance of this spontaneously derived genic male sterility
trait relating to the homeotic conversion of floral organs in marigold. 相似文献
157.
Andrew Leask 《Journal of cell communication and signaling》2010,4(2):109-110
The role of CCN proteins in vivo is only just becoming understood. A prototypical member of the CCN family, CCN3 suppresses proliferation. In a study in press, Shimoyama and colleagues show that mice lacking CCN3 have a hyperproliferative response to vascular injury. These data, along with other recent observations, suggest that CCN3 may represent a novel therapy for hyperproliferative diseases. 相似文献
158.
159.