全文获取类型
收费全文 | 1369篇 |
免费 | 117篇 |
出版年
2023年 | 6篇 |
2022年 | 16篇 |
2021年 | 35篇 |
2020年 | 27篇 |
2019年 | 33篇 |
2018年 | 46篇 |
2017年 | 37篇 |
2016年 | 49篇 |
2015年 | 70篇 |
2014年 | 77篇 |
2013年 | 101篇 |
2012年 | 116篇 |
2011年 | 107篇 |
2010年 | 72篇 |
2009年 | 66篇 |
2008年 | 93篇 |
2007年 | 67篇 |
2006年 | 65篇 |
2005年 | 66篇 |
2004年 | 52篇 |
2003年 | 47篇 |
2002年 | 55篇 |
2001年 | 24篇 |
2000年 | 21篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1992年 | 12篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1981年 | 3篇 |
1977年 | 5篇 |
1976年 | 10篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1971年 | 4篇 |
1961年 | 1篇 |
1953年 | 1篇 |
1948年 | 1篇 |
排序方式: 共有1486条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
Mayra Domínguez-Pérez Arturo Simoni-Nieves Patricia Rosales Natalia Nuño-Lámbarri Mónica Rosas-Lemus Verónica Souza Roxana U. Miranda Leticia Bucio Salvador Uribe Carvajal Jens U. Marquardt Daekwan Seo Luis E. Gomez-Quiroz María Concepción Gutiérrez-Ruiz 《Journal of cellular physiology》2019,234(5):7213-7223
55.
Willian Batista‐Silva David B. Medeiros Accio Rodrigues‐Salvador Danilo M. Daloso Rebeca P. Omena‐Garcia Franciele Santos Oliveira Lilian Ellen Pino Lzaro Eustquio Pereira Peres Adriano Nunes‐Nesi Alisdair R. Fernie Agustín Zsgn Wagner L. Araújo 《Plant, cell & environment》2019,42(2):448-465
Auxin modulates a range of plant developmental processes including embryogenesis, organogenesis, and shoot and root development. Recent studies have shown that plant hormones also strongly influence metabolic networks, which results in altered growth phenotypes. Modulating auxin signalling pathways may therefore provide an opportunity to alter crop performance. Here, we performed a detailed physiological and metabolic characterization of tomato (Solanum lycopersicum) mutants with either increased (entire) or reduced (diageotropica—dgt) auxin signalling to investigate the consequences of altered auxin signalling on photosynthesis, water use, and primary metabolism. We show that reduced auxin sensitivity in dgt led to anatomical and physiological modifications, including altered stomatal distribution along the leaf blade and reduced stomatal conductance, resulting in clear reductions in both photosynthesis and water loss in detached leaves. By contrast, plants with higher auxin sensitivity (entire) increased the photosynthetic capacity, as deduced by higher Vcmax and Jmax coupled with reduced stomatal limitation. Remarkably, our results demonstrate that auxin‐sensitive mutants (dgt) are characterized by impairments in the usage of starch that led to lower growth, most likely associated with decreased respiration. Collectively, our findings suggest that mutations in different components of the auxin signalling pathway specifically modulate photosynthetic and respiratory processes. 相似文献
56.
Gilberto N. Salvador Calebe Maia Guilherme M. Dutra Tiago C. Pessali Naraiana L. Benone Luciano F. A. Montag Tiago M. S. Freitas 《Zeitschrift fur angewandte Ichthyologie》2019,35(4):1039-1041
The present study provides the length–weight relationships (LWR) for eight fish species in 19 streams from the Pedreira River basin, a small tributary of the Guyana coastal drainages from Amapá State, Brazil. Fishes were collected at two occasions, one in November 2016, the other in July 2018, using hand nets, with 0.5 mm of mesh size and 0.25 m2 of mouth area, and trawl nets, with 0.5 mm of mesh size and 3 m long. Standard length and total weight were measured to determine the LWRs. The results show that the coefficient b varied between 2.798 and 3.380 and thus the values were within the expected range. 相似文献
57.
Corentin Bochaton Renaud Boistel Sandrine Grouard Ivan Ineich Anne Tresset Salvador Bailon 《Historical Biology》2019,31(2):140-156
This paper aims to demonstrate how subfossil bone remains from Pleistocene and Holocene deposits can help to reconstruct the history of recently extinct taxa through the example of Pholidoscelis lizards from the Guadeloupe Islands in the French West Indies. To achieve this, we conducted a new anatomical and zooarchaeological study of fossil Pholidoscelis remains collected from 23 archaeological and paleontological deposits on the Guadeloupe Islands from which this genus is nowadays absent. Our results shed light on the past existence of large Pholidoscelis lizards on all the Guadeloupe islands but also on the difficulties of confident specific identification for these remains. Nevertheless, we suggest a possible past occurrence of the now extinct Pholidoscelis major on nearly all of the Guadeloupe islands. In addition, we identified a new Pholidoscelis species, Pholidoscelis turukaeraensis sp. nov., on Marie-Galante Island, where no Pholidoscelis lizards were previously reported. This new species underwent an increase in size after the end of the Pleistocene period, possibly due to reduced predation pressure. We also highlight the consumption of Pholidoscelis lizards by pre-Columbian Amerindians and the huge impact of European colonization, which led to the extinction of all these lizards in less than 300 years.http://zoobank.org/urn:lsid:zoobank.org:pub:15C39436-A083-483F-B35E-78807B606904 相似文献
58.
59.
60.
Ferreira EO Salvador MJ Pral EM Alfieri SC Ito IY Dias DA 《Zeitschrift für Naturforschung. C, Journal of biosciences》2004,59(7-8):499-505
A new aurone 1 and two known substances, aurantiamide acetate (2) and tiliroside (3), were isolated from the ethanolic extract of Gomphrena agrestis. The structural determination of 1 was based on spectroscopic and spectrometric data. The substance was defined as (E)-3'-O-beta-D-glucopyranosyl-4,5,6,4'-tetrahydroxy-7,2'-dimethoxyaurone. Biological activity of the ethanolic crude extract and isolated compounds against bacteria, fungi and Leishmania amazonensis amastigotes was evaluated. This appears to be the first report documenting aurone and aurantiamide compounds in the Amaranthaceae family. In the evaluation of biological activity the ethanolic extract of G. agrestis and compounds 1, 2, and 3 were shown to be active mainly against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. 相似文献