全文获取类型
收费全文 | 267篇 |
免费 | 20篇 |
出版年
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 11篇 |
2015年 | 11篇 |
2014年 | 20篇 |
2013年 | 16篇 |
2012年 | 15篇 |
2011年 | 20篇 |
2010年 | 11篇 |
2009年 | 13篇 |
2008年 | 7篇 |
2007年 | 14篇 |
2006年 | 3篇 |
2005年 | 13篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1992年 | 7篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 8篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1964年 | 1篇 |
1963年 | 2篇 |
排序方式: 共有287条查询结果,搜索用时 15 毫秒
71.
Loss of growth homeostasis by genetic decoupling of cell division from biomass growth: implication for size control mechanisms
下载免费PDF全文
![点击此处可从《Molecular systems biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Growing cells adjust their division time with biomass accumulation to maintain growth homeostasis. Size control mechanisms, such as the size checkpoint, provide an inherent coupling of growth and division by gating certain cell cycle transitions based on cell size. We describe genetic manipulations that decouple cell division from cell size, leading to the loss of growth homeostasis, with cells becoming progressively smaller or progressively larger until arresting. This was achieved by modulating glucose influx independently of external glucose. Division rate followed glucose influx, while volume growth was largely defined by external glucose. Therefore, the coordination of size and division observed in wild‐type cells reflects tuning of two parallel processes, which is only refined by an inherent feedback‐dependent coupling. We present a class of size control models explaining the observed breakdowns of growth homeostasis. 相似文献
72.
73.
74.
75.
Qesem Cave is assigned to the Acheulo-Yabrudian cultural complex of the late Lower Paleolithic period. The 7.5 m deep stratigraphic sequence is dated to 400-200 ka (thousands of years ago). It is mostly attributed to the Amudian blade-dominated industry, one of the earliest blade production technologies in the world. In this paper, we present the results of a detailed study of five Amudian assemblages from Qesem Cave and suggest two trajectories for the production of blades at the site. We argue that the reduction sequences of blades at Qesem Cave represent an innovative and straightforward technology aimed at the systemic and serial production of predetermined blanks. We suggest that this predetermined blank technology shows planning and intensity that is not significantly different from Middle Paleolithic Mousterian technological systems. Furthermore, this well-organized serial manufacture of cutting implements mainly for butchering might indicates that a significant change in human behavior had taken place by the late Lower Paleolithic period. 相似文献
76.
Hernndez-Elvira Mariana Salas-Delgado Griselda Kawasaki Laura Domnguez-Martin Eunice Cruz-Martnez Uriel Olivares Abiram E. Torres-Quiroz Francisco Ongay-Larios Laura Coria Roberto 《International microbiology》2022,25(3):639-647
International Microbiology - In addition to the UPR pathway, yeast cells require components of the HOG pathway to respond to ER stress. In this work, we found that unphosphorylated Sln1 and Ssk1... 相似文献
77.
Uriel Hernndez‐Salinas Aurelio Ramírez‐Bautista Raciel Cruz‐Elizalde Shai Meiri Christian Berriozabal‐Islas 《Ecology and evolution》2019,9(4):2061-2071
Juvenile growth rates are thought to be restricted by available food resources. In animals that grow throughout the year, such as tropical lizards, growth is therefore predicted to be faster during the rainy season. We test this prediction using a population of Anolis nebulosusby describing the growth trajectories of both sexes using nonlinear regression models, and we then correlate the growth rates of individuals with food available in the environment, precipitation, and temperature. The Von Bertalanffy model fits the growth rates of the females better, while the logistic‐by‐length model fits the males better. According to both models, the males grew faster than females, reaching slightly smaller sizes at adulthood. Males reached sexual maturity when 35 mm long, at an age of seven months, and females matured at 37 mm (SVL), taking nine months to reach this size. In 1989, juvenile males and females grew more in both seasons (rainy and dry) than adults; for 1990, there were no differences by season or between age classes. These results are interesting since in the 1989 and 1990 rainy seasons, practically the same orders of prey and the greatest abundance of prey available in the environment were registered. A possible explanation could be that predation was more intense in 1990 than in 1989. There is little evidence that food, temperature, and humidity affect growth rates of A. nebulosus, refuting our predictions. This is mainly due to the low variation in growth observed in 1990. Therefore we think that the growth of this species reflects a complex combination of ecological and genetic factors. 相似文献
78.
Variation in morphological and reproductive characteristics of females of Anolis nebulosus (Squamata: Dactyloidae) from island and mainland populations near the Pacific Coast of Mexico
下载免费PDF全文
![点击此处可从《Acta zoologica》网站下载免费的PDF全文](/ch/ext_images/free.gif)
We present a comparative analysis of the morphological and reproductive characteristics of adult female Anolis nebulosus, an arboreal lizard found on both mainland and insular habitats near the Pacific Coast of Mexico. Females from San Pancho Island were larger in all measured morphological variables than females from Biological Field Station Chamela (BFSCH) on the mainland, and those also reproduced at smaller body size (snout‐vent length, SVL: range = 35–44, = 39 mm) than females on San Pancho Island (range = 40–47, = 43 mm). Egg mass and egg volume were also greater on San Pancho Island, but clutch frequency was higher on BFSCH during breeding season; in this place, one egg every 8 days over a period of 4 months (123 days) versus one egg every 10 days over a period of 4 months (130 days) on San Pancho Island. Thus, we conclude that certain characteristics related to reproduction (e.g. size at sexual maturity, egg mass and egg volume) in A. nebulosus with populations inhabiting islands and mainland, vary primarily in accordance with female SVL. These variations are most likely a response to the different pressures where A. nebulosus inhabits on environments the islands and mainland near the Pacific Coast of Mexico. 相似文献
79.
Bethany L. Krebs Tavis K. Anderson Tony L. Goldberg Gabriel L. Hamer Uriel D. Kitron Christina M. Newman Marilyn O. Ruiz Edward D. Walker Jeffrey D. Brawn 《Proceedings. Biological sciences / The Royal Society》2014,281(1796)
Animals can decrease their individual risk of predation by forming groups. The encounter-dilution hypothesis extends the potential benefits of gregariousness to biting insects and vector-borne disease by predicting that the per capita number of insect bites should decrease within larger host groups. Although vector-borne diseases are common and can exert strong selective pressures on hosts, there have been few tests of the encounter-dilution effect in natural systems. We conducted an experimental test of the encounter-dilution hypothesis using the American robin (Turdus migratorius), a common host species for the West Nile virus (WNV), a mosquito-borne pathogen. By using sentinel hosts (house sparrows, Passer domesticus) caged in naturally occurring communal roosts in the suburbs of Chicago, we assessed sentinel host risk of WNV exposure inside and outside of roosts. We also estimated per capita host exposure to infected vectors inside roosts and outside of roosts. Sentinel birds caged inside roosts seroconverted to WNV more slowly than those outside of roosts, suggesting that social groups decrease per capita exposure to infected mosquitoes. These results therefore support the encounter-dilution hypothesis in a vector-borne disease system. Our results suggest that disease-related selective pressures on sociality may depend on the mode of disease transmission. 相似文献
80.
Anne L. Wilson Ramesh C. Dhiman Uriel Kitron Thomas W. Scott Henk van den Berg Steven W. Lindsay 《PLoS neglected tropical diseases》2014,8(10)