全文获取类型
收费全文 | 172篇 |
免费 | 16篇 |
出版年
2022年 | 2篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 9篇 |
2012年 | 5篇 |
2011年 | 5篇 |
2010年 | 9篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有188条查询结果,搜索用时 15 毫秒
121.
122.
Michio Nakamura William C. McGrew Linda F. Marchant Toshisada Nishida 《Primates; journal of primatology》2000,41(3):237-248
Chimpanzees (Pan troglodytes schweinfurthii) in the Mahale Mountains National Park, Tanzania, scratch other individual's bodies while they groom them. This behavioral
pattern of “social scratch” is another example of locality-specific social behavior, or custom, as it is not found in the
Gombe National Park, Tanzania, about 150 km north of Mahale, nor has it been reported from any other sites of chimpanzee study.
Frequency of social scratch was correlated with frequency of social grooming, but not with frequency of self-scratch. Frequencies
of social scratch per grooming bout among adult and adoles-cent males, and from lactating females to infants or juveniles,
were high, and among males, higher-ranking males especially received more. These facts indicate some social function of the
behavior. Social scratch was directed mostly to the dorsal side of the body. However, when lactating females social scratched
to infants or juveniles, they scratched other body parts. Social scratch was not lateralized to left or right. We present
four hypotheses on the functional origin and on the learning process of this cultural behavioral pattern. 相似文献
123.
124.
Hand use for 8 activities was studied in 20 captive cotton-top tamarins (Saguinus oedipus). The purpose of the study was to discover if hand preferences existed across tasks and across subjects, and, if so, whether
these followed the patterns of preference inMacNeilage et al.'s (1987) “postural origins” theory of the evolution of hand preference and hemispheric specialization in primates.
This theory suggests that, for haplorines, the right hand is used preferentially for manipulative acts while the left hand
is used preferentially for visually guided acts. The study showed statistically significant right hand preferences for six
of the seven actions which produced sufficient data to be tested. The strength and consistency of this preference makes this
study the first to suggest true handedness in a non-human primate species. Deviations from the pattern were seen in scratching
and other actions when performed in a vertical posture, but these deviations took the form of a weakening of the right hand
preference rather than a reversal. The findings of the study may be seen as supportingMacNeilage et al.'s (1987) theoryonly if the actions studied are all considered to be manipulative, which can be argued to be the case, though some of the actions
were also visually guided. 相似文献
125.
A single lineage of r2 retrotransposable elements is an active, evolutionarily stable component of the Drosophila rDNA locus 总被引:1,自引:0,他引:1
R2 elements are non-long-terminal-repeat (non-LTR) retrotransposons that
insert specifically in the 28S rRNA genes of many insects. Previous reports
concerning this element in the genus Drosophila have suggested that R2
elements are absent from many species of this genus, particularly those
species from the subgenus Drosophila. In this report, we present an
extensive study of the distribution and evolution of R2 elements in
Drosophila. A PCR survey of 59 species from 23 species groups of the two
major Drosophila subgenera found that R2 elements are present in all but
two species of the melanogaster species subgroup. Phylogenetic analysis
based on partial nucleotide sequences of R2 elements from 23 species
demonstrates that the relationships of R2 elements are congruent with those
of the Drosophila species phylogeny, suggesting that these elements have
been vertically inherited since the divergence of this genus some 60 MYA.
Sequence variation between different copies of R2 elements within each
species was less than 0.16%, indicating that these elements are undergoing
concerted evolution similar to that of the 28S genes. Several properties of
the R2 sequences suggest that these elements depend on retrotransposition
in addition to simple recombination to remain within the rDNA locus: the
rates of synonymous substitutions averaged 4.8 times the rate of
replacement substitutions, 82 of 83 R2 copies partially sequenced contained
intact open reading frames, and, finally, length variation associated with
the poly(A) 3' tails indicated that many R2 copies are the direct result of
retrotransposition.
相似文献
126.
Grips and hand movements of chimpanzees during feeding in Mahale Mountains National Park,Tanzania
下载免费PDF全文
![点击此处可从《American journal of physical anthropology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mary W. Marzke Linda F. Marchant William C. McGrew Sandra P. Reece 《American journal of physical anthropology》2015,156(3):317-326
It has long been assumed that stone tool making was a major factor in the evolution of derived hominin hand morphology. However, stresses on the hand associated with food retrieval and processing also have been recognized as relevant early hominin behaviors that should be investigated. To this end, chimpanzee food manipulation was videotaped in the Mahale Mountains National Park, Tanzania. Grips and hand movements by 39 chimpanzees were analyzed for arboreal and terrestrial feeding involving 10 food‐types and associated vegetation. It was predicted that (1) new grips would be found that had not been observed in captivity, (2) forceful precision grips would be absent from the repertoire, as in captivity, and (3) precision handling would be observed. New grips involving the full thumb and buttressed index finger, and a new integrated pattern of grips and forceful hand movements were discovered, associated with feeding on large fruits and meat. Participation of the full thumb in these grips, rather than the distal thumb and fingers, throws light on feeding behaviors that may have become increasingly significant factors in the evolution of derived hominin thumb morphology. The proximal thumb stabilizes food with the flexed index finger against the pull of the teeth and provides leverage in breaking food into portions. Isolated qualitative observations of possibly forceful pinch by the thumb and side of the index finger highlight the need for comparative quantitative data to test whether humans are unique in forceful precision gripping capability. Precision handling was not seen. Am J Phys Anthropol 156:317–326, 2015. © 2014 Wiley Periodicals, Inc. 相似文献
127.
McGrew WC Marchant LF Hunt KD 《Folia primatologica; international journal of primatology》2007,78(4):240-244
We present the first indirect test of manually lateralized behaviour in non-human primates, based on wells dug for drinking water by wild chimpanzees (Pan troglodytes schweinfurthii). Apes at Toro-Semliki Wildlife Reserve, in Uganda, dig bimanually in sandy riverbeds, leaving behind paired piles of excavated sand. The volumes of left- versus right-side piles do not differ, suggesting a lack of behavioural laterality, but this needs to be verified by further, direct observational data. 相似文献
128.
129.
130.
Shomari DL Zack-Williams Peter E Butler Deepak M Kalaskar 《World journal of stem cells》2015,7(1):51-64
Unlike central nervous system neurons; those in the peripheral nervous system have the potential for full regeneration after injury. Following injury, recovery is controlled by schwann cells which replicate and modulate the subsequent immune response. The level of nerve recovery is strongly linked to the severity of the initial injury despite the significant advancements in imaging and surgical techniques. Multiple experimental model shave been used with varying successes to augment the natural regenerative processes which occur following nerve injury. Stem cell therapy in peripheral nerve injury may be an important future intervention to improve the best attainable clinical results. In particular adipose derived stem cells(ADSCs) are multipotent mesenchymal stem cells similar to bone marrow derived stem cells, which are thought to have neurotrophic properties and the ability to differentiate into multiple lineages. They are ubiquitous within adipose tissue; they can form many structures resembling the mature adult peripheral nervous system. Following early in vitro work; multiple small and large animal in vivo models have been used in conjunction with conduits, autografts and allografts to successfully bridge the peripheral nerve gap. Some of the ADSC related neuroprotective and regenerative properties have been elucidated however much work remains before a model can be used successfully in human peripheral nerve injury(PNI). This review aims to provide a detailed overview of progress made in the use of ADSC in PNI, with discussion on the role of a tissue engineered approach for PNI repair. 相似文献