首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   346篇
  免费   8篇
  国内免费   7篇
  2022年   2篇
  2021年   2篇
  2019年   2篇
  2018年   7篇
  2017年   1篇
  2015年   1篇
  2014年   1篇
  2013年   9篇
  2012年   11篇
  2011年   6篇
  2010年   6篇
  2009年   12篇
  2008年   10篇
  2007年   8篇
  2006年   12篇
  2005年   17篇
  2004年   17篇
  2003年   7篇
  2002年   8篇
  2001年   5篇
  2000年   4篇
  1999年   11篇
  1998年   13篇
  1997年   3篇
  1996年   4篇
  1995年   9篇
  1994年   16篇
  1993年   11篇
  1992年   10篇
  1991年   11篇
  1990年   14篇
  1989年   11篇
  1988年   7篇
  1987年   8篇
  1986年   5篇
  1985年   14篇
  1984年   6篇
  1983年   7篇
  1982年   8篇
  1981年   7篇
  1980年   6篇
  1979年   6篇
  1978年   2篇
  1977年   6篇
  1976年   1篇
  1975年   2篇
  1973年   2篇
  1972年   8篇
  1971年   2篇
  1970年   2篇
排序方式: 共有361条查询结果,搜索用时 93 毫秒
51.
Highly repeated DNA sequences from man, five other primate species and rat were compared using five restriction endonucleases. Calculations of a similarity index based on the mobility of various bands indicate that man, chimpanzee and baboons are very similar. The sequences of the genomes studied have apparently been reorganized during primate evolution.  相似文献   
52.
Engaging children in developing countries to care for wildlife, and to make appropriate choices to protect wildlife, are challenging tasks. Proyecto Tití works to conserve the cotton-top tamarin (Saguinus oedipus), a critically endangered endemic monkey from Colombia, using a multi-disciplinary approach that focuses on scientific research, community empowerment, habitat protection, and conservation education to protect this species. Proyecto Tití has developed a multi-tiered methodology for education in rural communities that increases knowledge and understanding of the cotton-top tamarin and the threats to its survival, generates attitudes and behavior that support conservation, and provides opportunities to develop the future generation of conservation leaders in Colombia. We evaluated TITÍ KIDS and CARTITILLA, two of Proyecto Tití’s educational programs, measuring the knowledge gained by students before and immediately after the program. For CARTITILLA, we also measured the retention of knowledge after five years, and if the program developed pro-conservation attitudes and behaviors. We analyzed the evaluations of over 6000 students who participated in programs from 2011 to 2016, using a paired t-test. Students significantly increased their knowledge of cotton-top tamarins (p  0.01) and their ability to identify and classify domesticated and wild animals in their regions (p  0.01). Five years after participating in the CARTITILLA program, students had retained their knowledge about cotton-top tamarins and demonstrated attitudes and behavior that support cotton-top tamarin conservation. The educational programs of Proyecto Tití provide evidence that engaging youth in meaningful conservation activities can assist in the protection of cotton-top tamarins.  相似文献   
53.
54.
A series of 60 chimpanzees (Pan troglodytes) were tested for their human-type A-B-O blood groups and for ten simian-type blood factors. Of the 60 chimpanzees four were group O and 56 group A; combining this with our previous results, among 274 chimpanzees there were 36 group O and 238 group A. Gene frequency analysis of the V-A-B types (determined by three antisera, anti- V c, anti- A c and anti- B c) of the 60 chimpanzees indicated inheritance by four allelic genes, namely, the amorphic gene v and the three additional alleles vA, vB and V. This theory allows for the existence of ten genotypes but only seven V-A-B phenotypes, since the type V.AB is excluded. Gene frequency analysis confirmed that Cc and cc are contrasting antigens determined by corresponding allelic genes. The distribution of the C-c-E-F types among the 60 chimpanzees, as well as among 133 chimpanzees previously tested, is compatible with the postulation of five allelic genes, namely, the amorph c, and the alleles CE, CF, CEF and the very rare allele C. The blood factor G c appears to define a separate blood group system, independent of the V-A-B and C-E-F systems. The newly defined blood factor Lindsay appears to be related to the V-A-B system, while factor H c may be related to the C-E-F system.  相似文献   
55.
Summary The distribution of adrenergic terminals to the anterior eye segment of humans, Cynomolgue monkeys, squirrel monkeys, owl monkeys, Cebus monkeys, vervets, tamarins, and baboons has been investigated. The cornea is normally devoid of adrenergic terminals, except in a plexus near the limbus. The trabecular meshwork contains varying numbers of adrenergic terminals: usually none in Cynomolgus monkeys, patas monkeys, vervets, and humans, although fibres have very rarely been observed in Cynomolgus monkeys, vervets, and humans; a few in owl monkeys, squirrel monkeys, and tamarins; and moderate numbers in Cebus monkeys and baboons. From the evidence, however, it seems premature to presume an adrenergic innervation of the trabecular mechanism regulating the outflow resistance. The dilatator pupillae is regularly supplied with numerous adrenergic terminals and in the iris stroma there is probably an adrenergic innervation of the melanophores. The sphincter pupillae regularly contains adrenergic terminals with notable species differences; most fibres occur in baboons and fewest in humans, with the remaining species forming a middle class. The ciliary processes in all species contain a moderate number of adrenergic terminals, presumably primarily associated with the epithelium. Intraepithelial adrenergic terminals have been observed on the pars plana of the ciliary body of humans, Cebus monkeys, vervets, baboons, and patas monkeys. The ciliary muscle of baboons and Cynomolgus monkeys contains numerous adrenergic terminals. Moderate numbers occur in Cebus monkeys and vervets, and still less in (in falling order) tamarins, squirrel monkeys, humans, and patas monkeys.  相似文献   
56.
This study is an exercise to check the efficiency of the existing reserve system, and to show how systematic conservation planning—using information available and the complementarity concept—can improve the basis for decisions and minimize costs. We verified the performance, in number of cells and primate species representation, of the existing Atlantic Forest (Brazil) reserve network with a quarter-degree resolution grid, with 1,884 cells. We used occurrence data of 20 endemic primate species, and the maps of 237 existing reserves. Reserve networks were selected to represent primate species first considering no pre-existing reserves in Atlantic Forest, and then, considering the existing reserve system, taking into account the minimum area for viable population of the larger species (Northern muriqui Brachyteles hypoxanthus). Reserve selection was carried out using the complementarity concept implemented by a simulated annealing algorithm. Primate species representation (at least one occurrence in the network) could be achieved with 8% of the existing reserve system (nine cells in relation to the 120 in the existing reserve system). We found that today’s reserve system represents 89% of endemic primate species, excluding the species Coimbra Filho’s titi monkey (Callicebus coimbrai) and Marcgraf’s capuchin (Cebus flavius). The networks selected without considering existing reserves contained nine cells. The networks selected considering existing reserves (120 cells), had two new cells necessary to represent all the primates. This does not mean that a viable alternative is to start from zero (i.e., nonexistent reserves). Identifying critical supplementary areas using biodiversity information to fill the gaps and then starting “conservation in practice” in these areas should be priorities.  相似文献   
57.
Recent excavations in northwestern Kenya have recovered a vertebrate fauna of late early or early late Oligocene age. Among the mammal remains, a fragmentary lower jaw and an isolated upper molar have been attributed to a small primate, Lokonepithecus manai gen. et sp. nov. Lokonepithecus is a primitive member of the Parapithecidae and possibly most closely related to Apidium from the Fayum. The new primate from Kenya is the youngest parapithecid known and its occurrence in the Oligocene of Kenya suggests that sub-Saharan Africa probably played a major role in the evolutionary history of several groups of mammals.  相似文献   
58.
Vieira  Emerson M.  Izar  Patrícia 《Plant Ecology》1999,145(1):75-82
The Brazilian Atlantic rainforest harbours at least 129 non-volant mammal species. There is also a diverse and numerous epiphytic flora associated with this Neotropical rainforest, including several species of Araceae. Nevertheless, knowledge of the ecology of this group of plants and its interaction with animals is poor. In this study we investigated the interactions between epiphytic aroids and arboreal mammals in the Atlantic forest. We carried out the field work between November 1995 and June 1997 in the Parque Estadual Intervales, southeastern Brazil, a still well preserved forest area of approximately 490 km2. We analysed faecal samples from primates (Cebus apella and Brachyteles arachnoides), collected during observations in the field, and marsupials (Didelphis aurita, Micoureus demerarae, Gracilinanus microtarsus), collected from animals captured monthly or bi-monthly in live-traps. We recorded 17 species of Araceae in the study area. The seeds of eight species occurred in the faecal samples: Anthurium harrissi, Monstera adansonii, Philodendron corcovadense, P. appendiculatum, P. exymium, P. crassinervium, P. obliquifolium, and Heteropsis oblongifolia. Aroids were present in faecal samples of the primates during most of the year, with a mean monthly percentage of occurrence of about 56.2%. For marsupials, aroids also were a seasonally important food source, as between November and June the mean monthly percentage of occurrence in faecal samples was about 26.5%. Our data indicate that aroids are an important food source for arboreal and semi-arboreal mammals and that these animals may play an important role as seed dispersers of this group. Aroids and arboreal mammals appear to interact more strongly in Atlantic forest than in other Neotropical forests.  相似文献   
59.
消息与动态     
《人类学学报》1993,12(1):96-96
这个会议于1992年6月30日至7月3日在西班牙北部拉摩塔(La Motta)城堡举行。会议是由西班牙国家博物馆、马德里康卜留腾斯(Complutense)大学等单位的有关部门组织的,除西班牙的有关专家外还邀请了近年在人属化石进化研究领域最活跃的外国专家如F.Clark Howell,M.H.Wolpoff,C.Stringer及J.J.Hublin等。会议重点是展示阿塔帕尔卡的人类化石、旧石器以及有关的古生物、地质等方面的科研成果,也报告世界近年在这些方面研究的新成果。会议期间还参观了阿塔帕尔卡的人类化石模型、石器及野外发掘现场。  相似文献   
60.
Patterns of interlimb coordination based on telemetered electromyography of extensor muscles are described for the brown lemur (Lemur fulvus) and the talapoin monkey (Miopithecus talapoin) in order to address the issue of possible motor programs for quadrupedal stepping in primates. Differences in modal patterns of ipsilateral limb coupling (phase intervals) between walking and galloping indicate that gait-specific programs do exist in primates, especially for symmetrical gaits. These preferred patterns distinguish primates from most other mammals (e.g., the domestic cat), but do not rule out the possibility of subtle differences among primates in species-specific mechanisms of neural control. Variability about the preferred modes is better interpreted as an expression of the flexibility or facultative capabilities of the neural mechanisms controlling locomotion than as “errors” in the motor program.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号