全文获取类型
收费全文 | 409篇 |
免费 | 32篇 |
出版年
2023年 | 3篇 |
2022年 | 10篇 |
2021年 | 9篇 |
2020年 | 11篇 |
2019年 | 18篇 |
2018年 | 16篇 |
2017年 | 20篇 |
2016年 | 21篇 |
2015年 | 35篇 |
2014年 | 32篇 |
2013年 | 31篇 |
2012年 | 42篇 |
2011年 | 21篇 |
2010年 | 22篇 |
2009年 | 18篇 |
2008年 | 12篇 |
2007年 | 18篇 |
2006年 | 16篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1967年 | 1篇 |
1966年 | 4篇 |
1965年 | 1篇 |
排序方式: 共有441条查询结果,搜索用时 15 毫秒
91.
Aline Semblano Carreira Falc?o Maria Sueli da Silva Kataoka Nélson Antonio Bail?o Ribeiro José Antonio Pican?o Diniz Jr Sérgio Melo Alves Jr André L. Ribeiro Ribeiro Adriane Sousa de Siqueira Artur Luiz da Silva Rommel Thiago Jucá Ramos Vanessa M. Freitas Ruy G. Jaeger Jo?o J. V. Pinheiro 《PloS one》2014,9(8)
92.
93.
S. Ivan Perez Verónica Lema José Alexandre Felizola Diniz‐Filho Valeria Bernal Paula N. Gonzalez Diego Gobbo Héctor M. Pucciarelli 《Journal of Biogeography》2011,38(1):148-163
Aim Understanding the importance of ecological factors in the origin and maintenance of patterns of phenotypic variation among populations, in an explicit geographical context, is one of the main goals of human biology, ecology and evolutionary biology. Here we study the ecological factors responsible for craniofacial variation among human populations from South America. Location South America. Methods We studied a dataset of 718 males from 40 South American populations, coming from groups that inhabited different geographical and ecological regions. Cranial size and shape variation were studied using 30 cranial measurements. We first used spatial correlograms and interpolated maps to address spatial patterns. We then regressed the shape (principal component scores) and size variables against ecology (mean annual temperature and diet) using multiple and multivariate spatial regression. Finally, the expected magnitudes of shape and size divergence under the influence of genetic drift and mutations alone were evaluated using neutral expectation for the divergence rate. Results The spatial correlograms showed a cline affecting the entire South American distribution. Interpolated maps showed that size and allometric shape vary from south‐east to north‐west. Multiple and multivariate regression analyses suggested that diet has the largest and most significant effect on this pattern of size and allometric shape variation. Finally, the results of the divergence rate test suggested that random processes alone cannot account for the morphological divergence exhibited by cranial size and allometric shape scores among southernmost populations. Main conclusions Correlograms, spatial regression and divergence rate analyses showed that although local factors (neutral processes or local environmental conditions) are important to explain spatial interpopulation differentiation in cranial characteristics among these populations, there is significant correlation of cranial size and allometric shape variation with diet. Gene flow among human populations, or local environmental conditions, could explain spatial variation mainly at smaller spatial scales, whereas the large‐scale pattern of the South American dataset is mainly related to the high proportion of carbohydrates and low proportion of proteins consumed. 相似文献
94.
95.
96.
97.
Photobiomodulation of mesenchymal stem cells encapsulated in an injectable rhBMP4‐loaded hydrogel directs hard tissue bioengineering
下载免费PDF全文
![点击此处可从《Journal of cellular physiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
98.
Thalita Macedo Araújo Magalhães Teixeira Souza Raphael Hermano Santos Diniz Celina Kiyomi Yamakawa Lauren Bergmann Soares Jaciane Lutz Lenczak Juliana Velasco de Castro Oliveira Gustavo Henrique Goldman Edilene Alves Barbosa Anna Clara Silva Campos Ieso Miranda Castro Rogelio Lopes Brandão 《Antonie van Leeuwenhoek》2018,111(10):1749-1766
This work was performed to verify the potential of yeast strains isolated from cachaça distilleries for two specific biotechnological applications: beer and bioethanol production. In the beer production, the strains were tested for characteristics required in brewery practices, such as: capacity to ferment maltose and maltotriose, ability to grow at lowest temperatures, low H2S production, and flocculation profile. Among the strains tested, two of them showed appropriate characteristics to produce two different beer styles: lager and ale. Moreover, both strains were tested for cachaça production and the results confirmed the capacity of these strains to improve the quality of cachaça. In the bioethanol production, the fermentation process was performed similarly to that used by bioethanol industries: recycling of yeast biomass in the fermentative process with sulfuric acid washings (pH 2.0). The production of ethanol, glycerol, organic acids, dry cell weight, carbohydrate consumption, and cellular viability were analyzed. One strain presented fermentative parameters similar to PE2, industrial/commercial strain, with equivalent ethanol yields and cellular viability during all fermentative cycles. This work demonstrates that cachaça distilleries seem to be an interesting environment to select new yeast strains to be used in biotechnology applications as beer and bioethanol production. 相似文献
99.
Duetting behavior in a Neotropical ovenbird: sexual and seasonal variation and adaptive signaling functions
下载免费PDF全文
![点击此处可从《Journal of avian biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Pedro Diniz Edvaldo F. da Silva Júnior Michael S. Webster Regina H. Macedo 《Journal of avian biology》2018,49(4)
Duetting is a collective behavior and might have multiple functions, including joint territory defense and mate guarding. An important step toward understanding the adaptive function of bird song is to determine if and how singing behavior varies seasonally. However, seasonal patterns for duetting species are different from the pattern described for species in which only the male sings, because song function may vary according to sex, singing role (initiator vs responder) and level of duet organization (individual vs pair). We investigated whether patterns of seasonal variation in duetting depends on these factors, which would suggest different interpretations of song function. We studied social pairs of a Neotropical bird species (rufous hornero Furnarius rufus) for seven consecutive months, recording vocal and territorial behaviors. Overall, partners coordinated 61% of their songs into duets and many song traits (song initiation rate, song output and duet rate) peaked in territorial contexts. Males engaged in territorial interactions with strangers more often, initiated more songs, and answered proportionately more of their partners’ songs than females. Male song initiation rate peaked during the pre‐ and post‐breeding stages, whereas females initiated more songs during the non‐breeding season. Both sexes answered partner songs faster and at higher rates during the pre‐breeding and female fertile stages. Partners duetted at a higher rate during the pre‐ and post‐breeding stages. Finally, song initiation rates and duet rate, but not song answering rates, correlated with frequency of territorial interactions with strangers. Although our findings indicate that song function may vary with sex, singing role and level of duet organization, our results suggest that in general duet functions to defend common territories and as a mutual mate guarding strategy in the rufous hornero. 相似文献
100.
The complete cDNA sequence and protein reading frame of a developmentally
regulated hemocyanin subunit in the Dungeness crab (Cancer magister) is
presented. The protein sequence is aligned with 18 potentially homologous
hemocyanin-type proteins displaying apparent sequence similarities.
Functional domains are identified, and a comparison of predicted
hydrophilicities, surface probabilities, and regional backbone
flexibilities provides evidence for a remarkable degree of structural
conservation among the proteins surveyed. Parsimony analysis of the protein
sequence alignment identifies four monophyletic groups on the arthropodan
branch of the hemocyanin gene tree: crustacean hemocyanins, insect
hexamerins, chelicerate hemocyanins, and arthropodan prophenoloxidases.
They form a monophyletic group relative to molluscan hemocyanins and
nonarthropodan tyrosinases. Arthropodan prophenoloxidases, although
functionally similar to tyrosinases, appear to belong to the arthropodan
hexamer- type hemolymph proteins as opposed to molluscan hemocyanins and
tyrosinases.
相似文献