全文获取类型
收费全文 | 686篇 |
免费 | 54篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 16篇 |
2020年 | 13篇 |
2019年 | 12篇 |
2018年 | 18篇 |
2017年 | 25篇 |
2016年 | 25篇 |
2015年 | 39篇 |
2014年 | 44篇 |
2013年 | 48篇 |
2012年 | 55篇 |
2011年 | 42篇 |
2010年 | 28篇 |
2009年 | 28篇 |
2008年 | 36篇 |
2007年 | 26篇 |
2006年 | 28篇 |
2005年 | 32篇 |
2004年 | 30篇 |
2003年 | 19篇 |
2002年 | 22篇 |
2001年 | 8篇 |
2000年 | 16篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 10篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有740条查询结果,搜索用时 15 毫秒
1.
2.
Contents of individual carotenoids in the fruits of Ramillete cultivar ofCapsicum annuum L. changed during ripening of recently harvested fruits or fruits stored 15 d in a dark and cool room. β-carotene and β-cryptoxanthin contents rose to a maximum and then declined, while the contents of other earotenoids rose to a rather steady level. Capsanthin was the main carotenoid which together with capsorubin were responsihle for the ripening colour. 相似文献
3.
4.
Cryptic species and colonization processes in Ophryotrocha (Annelida,Dorvilleidae) inhabiting vertebrate remains in the shallow‐water Mediterranean 下载免费PDF全文
Sergi Taboada Carlos Leiva Maria Bas Nancy Schult Damhnait McHugh 《Zoologica scripta》2017,46(5):611-624
Over the past several years, there has been growing interest in how bones of decaying mammals are colonized in the marine seabed. One of the most common opportunistic taxa occurring worldwide on bones is dorvilleid polychaetes of the genus Ophryotrocha. In a recent study in the Mediterranean, Ophryotrocha puerilis and Ophryotrocha alborana were two of the most abundant species occurring in experimentally deployed bones. These species have direct development and this makes them a suitable model to study the mechanisms and processes allowing organisms lacking a dispersive larval phase to colonize new substrates. Here, we address the colonization processes at the molecular level for populations of O. puerilis and O. alborana on experimentally deployed mammal bones in the shallow‐water Mediterranean collected over a year at 3‐month intervals. High genetic distances between some of the O. puerilis organisms collected indicated the occurrence of at least two cryptic sibling species (O. puerilis ‘Shallow’ and O. puerilis ‘Deep’) apart from O. puerilis sensu stricto. This was corroborated with phylogenetic analyses using an alignment of three concatenated genes (COI, 16S, H3) and with species delimitation analyses using COI. The haplotype network inferred from COI sequences for O. puerilis ‘Shallow’ showed a few common haplotypes shared between the two trimesters analysed and several other less represented haplotypes only present in one trimester. Thus, colonization of these experimental bones may have been achieved by a few organisms that arrived to the bones and were able to reseed, and by several individuals arriving to the experimental bones and not persisting across time. In contrast, the haplotype network for O. alborana revealed that none of the haplotypes present in three different trimesters were shared, suggesting that the populations arriving at the bones during each trimester were totally replaced by new individuals during the subsequent trimesters. Our study suggests that different species of shallow‐water Ophryotrocha occurring in the Mediterranean may have different patterns of substrate colonization despite sharing similar life histories. 相似文献
5.
6.
7.
Isabel Espejo Luciano Di Croce Sergi Aranda 《BioEssays : news and reviews in molecular, cellular and developmental biology》2020,42(12):2000203
Chromatin-bound proteins underlie several fundamental cellular functions, such as control of gene expression and the faithful transmission of genetic and epigenetic information. Components of the chromatin proteome (the “chromatome”) are essential in human life, and mutations in chromatin-bound proteins are frequently drivers of human diseases, such as cancer. Proteomic characterization of chromatin and de novo identification of chromatin interactors could, thus, reveal important and perhaps unexpected players implicated in human physiology and disease. Recently, intensive research efforts have focused on developing strategies to characterize the chromatome composition. In this review, we provide an overview of the dynamic composition of the chromatome, highlight the importance of its alterations as a driving force in human disease (and particularly in cancer), and discuss the different approaches to systematically characterize the chromatin-bound proteome in a global manner. 相似文献
8.
The variations in length and fresh and dry mass of etiolated hypocotyls of lupin during the growth have been studied. The
growth exhibited by the different zones delimited along the hypocotyl was dependent on the localization of the zone as well
as on the age of seedlings, but in both cases the pattern of growth was similar. During the period of growth studied (seedlings
7 to 21 d old), the growth of hypocotyl was basically due to cell elongation, since the relative elongation of cells was positively
correlated with the relative elongation of the hypocotyl. 相似文献
9.
Bartolomé Sabater 《Physiologia plantarum》1982,55(2):121-128
A molecular mechanism is proposed for unitary multiphasic uptake in which the carrier has two binding sites for the substrate. The first site binds n-1 molecules of substrate, and then one additional substrate molecule can become bound at the second binding site. Only this last molecule is transported in the operation of the carrier molecule. In the free state, the carrier can be activated to successive states with increasing affinities for the substrate in the two binding sites. The mechanism is resolved for the steady state conditions, obtaining a simple uptake rate equation, which fits the experimental data. Methods for determining the parameters of the equation are presented. Evidence other than kinetics is discussed for the mechanism. The mechanism also provides a physiological interpretation for multiphasic uptake: the active transport mechanisms (energy-requiring mechanisms) are prevented from operating at high substrate concentrations, thus preventing a waste of energy by the cells. 相似文献
10.
Colonization of dynamic Mediterranean landscapes: where do birds come from after fire? 总被引:5,自引:0,他引:5
Aim Two main mechanisms may explain post‐disturbance species colonization patterns of early successional habitats such as those originated by wildfires. First, post‐disturbance colonization is not limited by the dispersal ability of the species to reach the newly created open areas and, secondly, colonization is limited by dispersal. Under the first hypothesis, we expect, at a regional scale, to find similar post‐disturbance communities to develop on recently burned sites. However, colonization limited by dispersal will lead to strong between‐site variations in species composition. Location To test these hypotheses, we studied the post‐fire colonization patterns of nine open‐habitat bird species in eight distantly located wildfires in the north‐eastern Iberian Peninsula. Methods We censused post‐fire bird composition by means of field transects and identified potential colonization sources from species–habitat suitability maps derived from atlas data. Results Our results showed strong significant differences in post‐fire species composition between burnt areas. Burnt areas located in areas with low probability of species presence before the fire event showed lower species occurrence and richness after the fire. Main conclusions These results do not support the idea that early successional stages and open habitats have a homogeneous community structure at regional scales and suggest that dispersal is a key constraint determining bird colonization of post‐fire habitats. Further attention should be paid to landscape heterogeneity as a key factor in determining population dynamics of open‐habitat species in the light of current and future land‐use changes in Mediterranean regions. 相似文献