全文获取类型
| 收费全文 | 688篇 |
| 免费 | 87篇 |
| 国内免费 | 1篇 |
专业分类
| 776篇 |
出版年
| 2023年 | 3篇 |
| 2022年 | 4篇 |
| 2021年 | 21篇 |
| 2020年 | 9篇 |
| 2019年 | 13篇 |
| 2018年 | 8篇 |
| 2017年 | 7篇 |
| 2016年 | 15篇 |
| 2015年 | 18篇 |
| 2014年 | 31篇 |
| 2013年 | 38篇 |
| 2012年 | 54篇 |
| 2011年 | 49篇 |
| 2010年 | 31篇 |
| 2009年 | 26篇 |
| 2008年 | 36篇 |
| 2007年 | 34篇 |
| 2006年 | 28篇 |
| 2005年 | 37篇 |
| 2004年 | 39篇 |
| 2003年 | 25篇 |
| 2002年 | 33篇 |
| 2001年 | 15篇 |
| 2000年 | 11篇 |
| 1999年 | 24篇 |
| 1998年 | 14篇 |
| 1997年 | 7篇 |
| 1996年 | 8篇 |
| 1995年 | 10篇 |
| 1994年 | 5篇 |
| 1993年 | 9篇 |
| 1992年 | 9篇 |
| 1991年 | 14篇 |
| 1990年 | 10篇 |
| 1989年 | 7篇 |
| 1988年 | 11篇 |
| 1987年 | 5篇 |
| 1986年 | 8篇 |
| 1985年 | 7篇 |
| 1984年 | 6篇 |
| 1983年 | 6篇 |
| 1982年 | 7篇 |
| 1981年 | 3篇 |
| 1979年 | 5篇 |
| 1978年 | 3篇 |
| 1977年 | 5篇 |
| 1969年 | 1篇 |
| 1963年 | 1篇 |
| 1951年 | 1篇 |
| 1944年 | 1篇 |
排序方式： 共有776条查询结果，搜索用时 15 毫秒
771.
Inbal Ayalon Laura F. de Barros Marangoni Jennifer I. C. Benichou Dror Avisar Oren Levy 《Global Change Biology》2019,25(12):4194-4207
Coral reefs represent the most diverse marine ecosystem on the planet, yet they are undergoing an unprecedented decline due to a combination of increasing global and local stressors. Despite the wealth of research investigating these stressors, Artificial Light Pollution at Night (ALAN) or “ecological light pollution” represents an emerging threat that has received little attention in the context of coral reefs, despite the potential of disrupting the chronobiology, physiology, behavior, and other biological processes of coral reef organisms. Scleractinian corals, the framework builders of coral reefs, depend on lunar illumination cues to synchronize their biological rhythms such as behavior, reproduction and physiology. While, light pollution (POL) may mask and lead de‐synchronization of these biological rhythms process. To reveal if ALAN impacts coral physiology, we have studied two coral species, Acropora eurystoma and Pocillopora damicornis, from the Gulf of Eilat/Aqaba, Red Sea, which is undergoing urban development that has led to severe POL at night. Our two experimental design data revealed that corals exposed to ALAN face an oxidative stress condition, show lower photosynthesis performances measured by electron transport rate (ETR), as well as changes in chlorophyll and algae density parameters. Testing different lights such as Blue LED and White LED spectrum showed more extreme impact in comparison to Yellow LEDs on coral physiology. The finding of this work sheds light on the emerging threat of POL and the impacts on the biology and ecology of Scleractinian corals, and will help to formulate specific management implementations to mitigate its potentially harmful impacts. 相似文献
772.
773.
The molecular mechanisms regulating intrinsic axon growth potential during development or following injury remain largely unknown despite their vast importance. Here, we have established a neurite sprouting assay of primary cultured mushroom body (MB) neurons. We used the MARCM technique to both mark and manipulate MB neurons, enabling us to quantify the sprouting abilities of single WT and mutant neurons originating from flies at different developmental stages. Sprouting of dissociated MB neurons was dependent on wnd, the DLK ortholog, a conserved gene that is required for axon regeneration. Next, and as expected, we found that the sprouting ability of adult MB neurons was significantly decreased. In contrast, and to our surprise, we found that pupal‐derived neurons exhibit increased sprouting compared with neurons derived from larvae, suggesting the existence of an elevated growth potential state. We then contrasted the molecular requirements of neurite sprouting to developmental axon regrowth of MB ? neurons, a process that we have previously shown requires the nuclear receptor UNF acting via the target of rapamycin (TOR) pathway. Strikingly, we found that while TOR was required for neurite sprouting, UNF was not. In contrast, we found that PTEN inhibits sprouting in adult neurons, suggesting that TOR is regulated by the PI3K/PTEN pathway during sprouting and by UNF during developmental regrowth. Interestingly, the PI3K pathway as well as Wnd were not required for developmental regrowth nor for initial axon outgrowth suggesting that axon growth during circuit formation, remodeling, and regeneration share some molecular components but differ in others. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 262–276, 2016 相似文献
774.
Responses of forest ecosystems to increased atmospheric CO2 concentration have been studied in few free‐air CO2 enrichment (FACE) experiments during last two decades. Most studies focused principally on the overstory trees with little attention given to understory vegetation. Despite its small contribution to total productivity of an ecosystem, understory vegetation plays an important role in predicting successional dynamics and future plant community composition. Thus, the response of understory vegetation in Pinus taeda plantation at the Duke Forest FACE site after 15–17 years of exposure to elevated CO2, 6–13 of which with nitrogen (N) amendment, was examined. Aboveground biomass and density of the understory decreased across all treatments with increasing overstory leaf area index (LAI). However, the CO2 and N treatments had no effect on aboveground biomass, tree density, community composition, and the fraction of shade‐tolerant species. The increases of overstory LAI (~28%) under elevated CO2 resulted in a reduction of light available to the understory (~18%) sufficient to nullify the expected growth‐enhancing effect of elevated CO2 on understory vegetation. 相似文献
775.
Danny Bavli Xue Sun Chen Kozulin Dena Ennis Alex Motzik Alva Biran Shlomi Brielle Adi Alajem Eran Meshorer Amnon Buxboim Oren Ram 《Developmental cell》2021,56(12):1804-1817.e7
- Download : Download high-res image (151KB)
- Download : Download full-size image
776.
Changfu Yao Stephanie A. Bora Tanyalak Parimon Tanzira Zaman Oren A. Friedman Joseph A. Palatinus Nirmala S. Surapaneni Yuri P. Matusov Giuliana Cerro Chiang Alexander G. Kassar Nayan Patel Chelsi E.R. Green Adam W. Aziz Harshpreet Suri Jo Suda Andres A. Lopez Gislâine A. Martins Barry R. Stripp Peter Chen 《Cell reports》2021,34(1):108590
- Download : Download high-res image (182KB)
- Download : Download full-size image