全文获取类型
收费全文 | 14420篇 |
免费 | 1041篇 |
国内免费 | 7篇 |
专业分类
15468篇 |
出版年
2023年 | 132篇 |
2022年 | 271篇 |
2021年 | 486篇 |
2020年 | 337篇 |
2019年 | 428篇 |
2018年 | 539篇 |
2017年 | 474篇 |
2016年 | 645篇 |
2015年 | 817篇 |
2014年 | 912篇 |
2013年 | 1008篇 |
2012年 | 1113篇 |
2011年 | 1021篇 |
2010年 | 603篇 |
2009年 | 547篇 |
2008年 | 687篇 |
2007年 | 701篇 |
2006年 | 584篇 |
2005年 | 513篇 |
2004年 | 470篇 |
2003年 | 394篇 |
2002年 | 362篇 |
2001年 | 244篇 |
2000年 | 212篇 |
1999年 | 179篇 |
1998年 | 90篇 |
1997年 | 81篇 |
1996年 | 87篇 |
1995年 | 73篇 |
1994年 | 82篇 |
1993年 | 43篇 |
1992年 | 100篇 |
1991年 | 106篇 |
1990年 | 77篇 |
1989年 | 83篇 |
1988年 | 70篇 |
1987年 | 74篇 |
1986年 | 85篇 |
1985年 | 61篇 |
1984年 | 59篇 |
1983年 | 50篇 |
1982年 | 44篇 |
1981年 | 41篇 |
1980年 | 31篇 |
1979年 | 39篇 |
1978年 | 45篇 |
1977年 | 36篇 |
1975年 | 42篇 |
1973年 | 33篇 |
1972年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
Marciane Danniela Fleck Ervandil Corrêa Costa Maristela Machado Araujo Karine Schoeninger Leonardo Mortari Machado Jéssica Maus da Silva Leandra Pedron Dayanna do Nascimento Machado Jardel Boscardin 《Revista Brasileira de Entomologia》2019,63(3):212-216
Forest species can have their seeds damaged by granivorous insects, especially by those in their larval stage. In this context, this study aims to report the occurrence of Amblycerus species in Cordia trichotoma seeds, to describe their main damage to seeds and effects on germination, as well as their associated hymenopteran parasitoids. Therefore, seven trees were selected in the municipality of Taquaruçu do Sul, RS, Brazil. Fruits were collected weekly from the medium third of the tree crown, from the beginning of their formation until total dehiscence. To examine the damage caused by granivorous insects within the fruits, 15 fruits from each tree were sectioned with a scalpel. Furthermore, 10 fruits from each tree were stored individually in clear plates to verify the occurrence and identification of granivorous insect species. Evidence of the damage caused to seeds was verified through the germination test by comparing preserved and damaged seeds, with four repetitions of 25 seeds each. The species Amblycerus longesuturalis and Amblycerus profaupar (Chrysomelidae: Bruchinae) were found associated with fruits of C. trichotoma. Female insects predominantly laid eggs on the superior part between the marcescent calyx and the fruit, and larvae perforated the fruit tegument to start consuming seed embryos and reserves. Bruquine larvae are parasitized by Hymenoptera of Bracon, Mirax, Omeganastatus and Triapsis genera. In conclusion, the germination of C. trichotoma seeds is significantly affected by emergence orifices caused by granivorous species. 相似文献
994.
de Queiroz João Vitor Vieira José Cavalcante Souza de Oliveira Grasieli Braga Camila Pereira da Cunha Bataglioli Izabela da Silva Janaína Macedo de Paula Araújo Wellington Luiz de Magalhães Padilha Pedro 《Biological trace element research》2019,187(1):291-300
Biological Trace Element Research - Predator fish can accumulate high levels of mercury, which qualifies them as potential indicators of this toxic metal. The predatory species Brachyplatystoma... 相似文献
995.
de Oliveira Hellen Oliveira de Castro Gledson Luiz Salgado Correa Lorena Oliveira Silvestre Walter Vellasco Duarte do Nascimento Sidney Vasconcelos da Silva Valadares Rafael Borges de Oliveira Guilherme Corrêa Santos Rodolfo Inacio Nunes Festucci-Buselli Reginaldo Alves Pinheiro Hugo Alves 《Photosynthesis research》2019,140(2):189-205
Photosynthesis Research - This study examined whether drought sensitivity in açaí (Euterpe oleracea Mart.) is associated with reductions in photosynthesis and increasing oxidative stress... 相似文献
996.
997.
998.
999.
Sylvia R Silveira Constance Le Gloanec Andrea Gmez-Felipe Anne-Lise Routier-Kierzkowska Daniel Kierzkowski 《Plant physiology》2022,188(2):769
Development of multicellular organisms is a complex process involving precise coordination of growth among individual cells. Understanding organogenesis requires measurements of cellular behaviors over space and time. In plants, such a quantitative approach has been successfully used to dissect organ development in both leaves and external floral organs, such as sepals. However, the observation of floral reproductive organs is hampered as they develop inside tightly closed floral buds, and are therefore difficult to access for imaging. We developed a confocal time-lapse imaging method, applied here to Arabidopsis (Arabidopsis thaliana), which allows full quantitative characterization of the development of stamens, the male reproductive organs. Our lineage tracing reveals the early specification of the filament and the anther. Formation of the anther lobes is associated with a temporal increase of growth at the lobe surface that correlates with intensive growth of the developing locule. Filament development is very dynamic and passes through three distinct phases: (1) initial intense, anisotropic growth, and high cell proliferation; (2) restriction of growth and proliferation to the filament proximal region; and (3) resumption of intense and anisotropic growth, displaced to the distal portion of the filament, without cell proliferation. This quantitative atlas of cellular growth dynamics provides a solid framework for future studies into stamen development. 相似文献