全文获取类型
收费全文 | 2023篇 |
免费 | 97篇 |
国内免费 | 2篇 |
出版年
2021年 | 17篇 |
2020年 | 14篇 |
2019年 | 18篇 |
2018年 | 30篇 |
2017年 | 16篇 |
2016年 | 38篇 |
2015年 | 76篇 |
2014年 | 71篇 |
2013年 | 144篇 |
2012年 | 143篇 |
2011年 | 118篇 |
2010年 | 73篇 |
2009年 | 100篇 |
2008年 | 128篇 |
2007年 | 143篇 |
2006年 | 127篇 |
2005年 | 136篇 |
2004年 | 131篇 |
2003年 | 128篇 |
2002年 | 124篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 17篇 |
1998年 | 27篇 |
1997年 | 26篇 |
1996年 | 26篇 |
1995年 | 23篇 |
1994年 | 11篇 |
1993年 | 22篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 10篇 |
1987年 | 16篇 |
1986年 | 6篇 |
1985年 | 12篇 |
1984年 | 6篇 |
1983年 | 10篇 |
1982年 | 5篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1965年 | 3篇 |
1964年 | 2篇 |
1963年 | 2篇 |
排序方式: 共有2122条查询结果,搜索用时 31 毫秒
971.
972.
973.
We hypothesized that movement fluctuations in the index finger reflect the integrated result of the coordination of multiple muscles because index finger movements are determined by the cooperation of multiple muscles spanning the metacarpophalangeal (MCP) joint. To evaluate this hypothesis, the aim of the present study was to examine the fluctuations of the index finger in abduction-adduction and extension-flexion directions during a position-holding task using two laser displacement sensors. Eleven healthy men maintained their index finger position while supporting a load at 5% of the maximal voluntary contraction force. To maintain the position of the index finger, displacement of the index finger in the abduction-adduction and extension-flexion directions was measured from a distance with two laser displacement sensors that were positioned to the lateral side of and above the index finger. The index finger movements fluctuated around the target position in not only the abduction-adduction direction but also the extension-flexion direction. The path length of finger displacement and the standard deviation of finger acceleration were significantly greater in the extension-flexion direction than in the abduction-adduction direction. These results suggest that the index finger movements quantified by two laser displacement sensors reflect the coordination of multiple muscles spanning the MCP joint. 相似文献
974.
975.
The study of vocal communication of wild mandrills in Cameroon in relation to their social structure 总被引:3,自引:0,他引:3
Hiroko Kudo 《Primates; journal of primatology》1987,28(3):289-308
The vocal repertoire of the mandrill (Mandrillus sphinx), a forest living baboon, is described, and their vocal communication analyzed quantitatively. Although the vocal repertoire
of mandrills corresponds well to that of savanna living baboons,Papio, some characteristics differed, such as the development of long-distance calls and differentiation of vocalizations between
age-sex classes. Vocal communication within a group was closely related to changes in the spatial distribution of group members,
and the two most common vocalizations, crowing and 2PG, appear to function as contact calls. Based on the wide dispersion
of food trees, a group of mandrills divided into several feeding groups (subgroups). The two types of contact call were given
in different and in some senses complementary contexts, and helped to facilitate and maintain group integration. According
to their acoustic structure, these calls are long distance calls. Influenced by the high-level of attenuation of vocalization
on the forest floor, the mandrill has developed them as contact calls, instead of using the contact “grunt,” which is common
to the savanna living baboons. Comparing the patterns of vocal exchanges of mandrills with those of gelada and hamadryas baboons
which have a multi-levelled society, the social structure of the mandrill is discussed. From the analysis of the spatial distribution
of vocal emission, a number of clusters of vocalizations were obtained. These clusters correspond to subgroups. The frequent
female-female and female-male vocal exchange between subgroups of mandrills suggest that the relationships between subgroups
are less closed than between the one-male units of gelada and hamadryas baboons. Furthermore some of these clusters include
more than two vocalizing adult males, while in other clusters there are no vocalizing adult males. Thus, the social structure
of mandrills is suggested to be multi-male rather than a multilevelled type. The absence of contact calls specific for short
distance and the functional replacement of the grunting of all group members by persistent emission of a loud call (2PG) by
usually just one adult male suggests that the social structure of mandrills is not exactly equivalent to that of the multimale
troop of savanna living baboons. Usually the use of 2PG is monopolized by one adult male travelling in the rear part of the
group. Such monopolization of 2PG emission and the pattern of 2PG-2PG or 2PG-roar exchanges by adult males in some cases indicate
the existence of strong dominance relationships among adult males, and especially the existence of a leader male within a
multi-male group of mandrills. 相似文献
976.
It is not always easy to apply microarray technology to small numbers of cells because of the difficulty in selectively isolating
mRNA from such cells. We report here the preparation of mRNA from ciliated sensory neurons of Caenorhabditis elegans using the mRNA-tagging method, in which poly(A) RNA was co-immunoprecipitated with an epitope-tagged poly(A)-binding protein
specifically expressed in sensory neurons. Subsequent cDNA microarray analyses led to the identification of a panel of sensory
neuron-expressed genes. 相似文献
977.
978.
Hiroko Yokochi Michio Tanaka Mari Kumashiro Atsushi Iriki 《Somatosensory & motor research》2013,30(2):115-125
Neuronal activities of the anterior part of the inferior parietal lobule (area 7b or PF) were investigated in five awake Japanese monkeys. There were neurons which had specific combinations of receptive field (RF) locations, most typically in both the face and hand; we refer to these as Face-Hand neurons. The most interesting property of the Face-Hand neurons is that some of these neurons responded to specific behavior executed with synergism between the face (especially the mouth) and hand movements; namely, face-hand coordinated behavior (e.g., eating behavior). We call these cells Face-Hand coordination neurons (52% of all the Face-Hand neurons). These neurons discharged more strongly when the animal executed face-hand coordinated behavior, especially eating behavior, than when somatosensory stimuli were given to RFs passively, or when face movements and hand movements were executed separately. We thus propose that the neuronal activities of area 7b are related to the representation of face-hand coordination. 相似文献
979.
Sabine M. H?lter Mary Stromberg Marina Kovalenko Lillian Garrett Lisa Glasl Edith Lopez Jolene Guide Alexander G?tz Wolfgang Hans Lore Becker Birgit Rathkolb Jan Rozman Anja Schrewed Martin Klingenspor Thomas Klopstock Holger Schulz Eckhard Wolf Wolfgang Wursta Tammy Gillis Hiroko Wakimoto Jonathan Seidman Marcy E. MacDonald Susan Cotman Valérie Gailus-Durner Helmut Fuchs Martin Hrabě de Angelis Jong-Min Lee Vanessa C. Wheeler 《PloS one》2013,8(11)
Huntington’s disease (HD) is an autosomal dominant neurodegenerative disorder caused by the expansion of a CAG trinucleotide repeat in the HTT gene encoding huntingtin. The disease has an insidious course, typically progressing over 10-15 years until death. Currently there is no effective disease-modifying therapy. To better understand the HD pathogenic process we have developed genetic HTT CAG knock-in mouse models that accurately recapitulate the HD mutation in man. Here, we describe results of a broad, standardized phenotypic screen in 10-46 week old heterozygous HdhQ111 knock-in mice, probing a wide range of physiological systems. The results of this screen revealed a number of behavioral abnormalities in HdhQ111/+ mice that include hypoactivity, decreased anxiety, motor learning and coordination deficits, and impaired olfactory discrimination. The screen also provided evidence supporting subtle cardiovascular, lung, and plasma metabolite alterations. Importantly, our results reveal that a single mutant HTT allele in the mouse is sufficient to elicit multiple phenotypic abnormalities, consistent with a dominant disease process in patients. These data provide a starting point for further investigation of several organ systems in HD, for the dissection of underlying pathogenic mechanisms and for the identification of reliable phenotypic endpoints for therapeutic testing. 相似文献
980.
Three new sesquiterpene lactones of the germacranolide-type [(11R)-11,13-dihydrotatridin-A, (11R)-11,13-dihydrotatridin-B and (11R)-6-O 相似文献