全文获取类型
收费全文 | 467篇 |
免费 | 34篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 18篇 |
2020年 | 17篇 |
2019年 | 15篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 17篇 |
2015年 | 27篇 |
2014年 | 19篇 |
2013年 | 35篇 |
2012年 | 46篇 |
2011年 | 30篇 |
2010年 | 19篇 |
2009年 | 20篇 |
2008年 | 22篇 |
2007年 | 41篇 |
2006年 | 24篇 |
2005年 | 18篇 |
2004年 | 24篇 |
2003年 | 14篇 |
2002年 | 15篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1952年 | 1篇 |
1943年 | 1篇 |
1921年 | 2篇 |
排序方式: 共有501条查询结果,搜索用时 31 毫秒
121.
Sasha K. Whitmarsh Peter G. Fairweather Charlie Huveneers 《Journal of fish biology》2019,95(3):952-955
We compared night deployments of Baited Remote Underwater Video Stations (BRUVS) in South Australia, illuminated by either red or blue light and found similar species compositions and abundances with both colours. We observed c. 1800 individuals from 52 species across 107 night-time deployments, with only one site out of six showing differences in assemblages between the two colours. With five out of six sites showing similarities between light colours our results differ from previous results and more generally suggest that the most suitable colour can differ among studies. 相似文献
122.
Elin Videvall Se Jin Song Hanna M. Bensch Maria Strandh Anel Engelbrecht Naomi Serfontein Olof Hellgren Adriaan Olivier Schalk Cloete Rob Knight Charlie K. Cornwallis 《Molecular ecology》2019,28(10):2653-2667
The development of gut microbiota during ontogeny is emerging as an important process influencing physiology, immunity and fitness in vertebrates. However, knowledge of how bacteria colonize the juvenile gut, how this is influenced by changes in the diversity of gut bacteria and to what extent this influences host fitness, particularly in nonmodel organisms, is lacking. Here we used 16S rRNA gene sequencing to describe the successional development of the faecal microbiome in ostriches (Struthio camelus, n = 66, repeatedly sampled) over the first 3 months of life and its relationship to growth. We found a gradual increase in microbial diversity with age that involved multiple colonization and extinction events and a major taxonomic shift in bacteria that coincided with the cessation of yolk absorption. Comparisons with the microbiota of adults (n = 5) revealed that the chicks became more similar in their microbial diversity and composition to adults as they aged. There was a five‐fold difference in juvenile growth during development, and growth during the first week of age was strongly positively correlated with the abundance of the genus Bacteroides and negatively correlated with Akkermansia. After the first week, the abundances of six phylogenetically diverse families (Peptococcaceae, S24‐7, Verrucomicrobiae, Anaeroplasmataceae, Streptococcaceae, Methanobacteriaceae) were associated with subsequent reductions in chick growth in an age‐specific and transient manner. These results have broad implications for our understanding of the development of gut microbiota and its associations with animal growth. 相似文献
123.
124.
Background
The glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) evolved from a common ancestor. Still not completely understood is how specificity for glucocorticoids (e.g. cortisol) and mineralocorticoids (e.g. aldosterone) evolved in these receptors. 相似文献125.
Xiwen Xiong Rongya Tao Ronald A. DePinho X. Charlie Dong 《The Journal of biological chemistry》2012,287(46):39107-39114
126.
Wu D Sullards MC Oldham CD Gelbaum L Lucrezi J Pullman GS May SW 《The New phytologist》2012,193(2):313-326
? Myo-inositol hexakisphosphate (InsP(6)), abundant in animals and plants, is well known for its anticancer activity. However, many aspects of InsP(6) function in plants remain undefined. We now report the first evidence that InsP(6) can inhibit cellular proliferation in plants under growth conditions where phosphorus is not limited. ? A highly anionic molecule inhibitory to early-stage somatic embryo growth of loblolly pine (LP) was purified chromatographically from late-stage LP female gametophytes (FGs), and then characterized structurally using mass spectrometry (MS) and nuclear magnetic resonance (NMR) analyses. ? Exact mass and mass spectrometry-mass spectrometry (MS-MS) fragmentation identified the bioactive molecule as an inositol hexakisphosphate. It was then identified as the myo-isomer (i.e. InsP(6)) on the basis of (1)H-, (31)P- and (13)C-NMR, (1)H-(1)H correlation spectroscopy (COSY), (1)H-(31)P heteronuclear single quantum correlation (HSQC) and (1)H-(13)C HSQC. Topical application of InsP(6) to early-stage somatic embryos indeed inhibits embryonic growth. ? Recently evidence has begun to emerge that InsP(6) may also play a regulatory role in plant cells. We anticipate that our findings will help to stimulate additional investigations aimed at elucidating the roles of inositol phosphates in cellular growth and development in plants. 相似文献
127.
Water as an Essential Resource: Orb Web Spiders Cannot Balance Their Water Budget by Prey Alone 总被引:1,自引:0,他引:1
André Walter Natasha Cadenhead Valerie Sze Weii Lee Charlie Dove Emma Milley Mark A. Elgar 《Ethology : formerly Zeitschrift fur Tierpsychologie》2012,118(6):534-542
Water is essential for all living organisms because it acts as a major solvent and reaction medium. Terrestrial animals may lose water through evaporation and excretion and consequently have evolved strategies to balance their water budget by either minimising losses or by gaining water. The major pathway to gain water is via food intake, although many animals additionally drink free water. Spiders acquire substantial amounts of water by ingesting enzymatically liquefied prey. However, this may not account for the water needs of some species. We tested whether drinking is essential for orb web spiders of the genus Argiope by experimentally manipulating the diet (flies or crickets) and water supply (no water or a daily shower) to females and then measuring their subsequent drinking behaviour. Individuals of Argiope trifasciata, which are typically found in dry habitats, increased their body mass when fed crickets but not when fed flies. However, spiders deprived of water subsequently ingested significantly more water than spiders that received water every day, regardless of their feeding regime. This pattern was replicated in Argiope aetherea, which is found in the tropics and perhaps less likely to be water deprived in natural populations. Our results reveal that drinking allows these spiders to realise their water balance independent from the nutritional status. We suggest that the spiders may need to drink fresh water to process ingested nutrients. 相似文献
128.
129.
130.
Thomas R. Gillespie David Morgan J. Charlie Deutsch Mark S. Kuhlenschmidt Johanna S. Salzer Kenneth Cameron Trish Reed Crickette Sanz 《EcoHealth》2009,6(4):557-564
Many studies have examined the long-term effects of selective logging on the abundance and diversity of free-ranging primates.
Logging is known to reduce the abundance of some primate species through associated hunting and the loss of food trees for
frugivores; however, the potential role of pathogens in such primate population declines is largely unexplored. Selective
logging results in a suite of alterations in host ecology and forest structure that may alter pathogen dynamics in resident
wildlife populations. In addition, environmental pollution with human fecal material may present a risk for wildlife infections
with zoonotic protozoa, such as Cryptosporidium and Giardia. To better understand this interplay, we compared patterns of infection with these potentially pathogenic protozoa in sympatric
western lowland gorillas (Gorilla gorilla gorilla) and chimpanzees (Pan troglodytes troglodytes) in the undisturbed Goualougo Triangle of Nouabalé-Ndoki National Park and the adjacent previously logged Kabo Concession
in northern Republic of Congo. No Cryptosporidium infections were detected in any of the apes examined and prevalence of infection with Giardia was low (3.73% overall) and did not differ between logged and undisturbed forest for chimpanzees or gorillas. These results
provide a baseline for prevalence of these protozoa in forest-dwelling African apes and suggest that low-intensity logging
may not result in long-term elevated prevalence of potentially pathogenic protozoa. 相似文献