全文获取类型
收费全文 | 1143篇 |
免费 | 72篇 |
国内免费 | 12篇 |
出版年
2024年 | 2篇 |
2023年 | 14篇 |
2022年 | 11篇 |
2021年 | 21篇 |
2020年 | 39篇 |
2019年 | 44篇 |
2018年 | 44篇 |
2017年 | 29篇 |
2016年 | 54篇 |
2015年 | 35篇 |
2014年 | 73篇 |
2013年 | 86篇 |
2012年 | 45篇 |
2011年 | 58篇 |
2010年 | 46篇 |
2009年 | 64篇 |
2008年 | 73篇 |
2007年 | 75篇 |
2006年 | 56篇 |
2005年 | 50篇 |
2004年 | 29篇 |
2003年 | 30篇 |
2002年 | 32篇 |
2001年 | 19篇 |
2000年 | 23篇 |
1999年 | 20篇 |
1998年 | 19篇 |
1997年 | 9篇 |
1996年 | 13篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 11篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有1227条查询结果,搜索用时 343 毫秒
21.
Paola Villa 《Evolutionary anthropology》1992,1(3):93-104
The key argument for the identification of prehistoric cannibalism is provided by analysis of close similarities in the treatment of human and animal remains. Such analysis requires precise data on depositional context, meticulous excavation records, detailed bone modification studies, a relatively large sample of human and animal postcranial bones, and data on local mortuary practices. With the exception of Fontbrégoua Cave, these necessary conditions are lacking at all Stone Age European sites where it has been hypothesized that cannibalism occurred. The alternative hypothesis of secondary burial practices has been proposed informally for some sites and, in a more formal and detailed way, for Krapina and Fontbrégoua. However, this hypothesis does not have a higher probability, is not justified by current data, and uses ethnographic analogies to prop up interpretations of materials for which contextual data are missing or have been neglected. At Fontbrégoua, cannibalism remains the simplest and most plausible explanation of the evidence; at Krapina and other sites the available evidence is insufficient to prove either secondary burial or cannibalism. 相似文献
22.
B. Mohanty H. Takahara T. Tachibana D. R. Naik H. Nogami 《Cell and tissue research》1993,273(3):427-434
Light-microscopic immunocytochemistry of ferret anterior pituitary revealed the localization of somatotropes in the pars distalis, but no immunoreactive cells were detected in the pars tuberalis. Ultrastructural studies by superimposition immunocytochemistry and immuno-electron microscopy, clucidated the morphological heterogeneity of these somatotropic cells. They were classified into 2 subtypes on the basis of size of the secretory granules. Type-I cells with small granules (mean diameter, 192 nm), were considered to be the immature somatotrop, while Type-II cells, with comparatively larger secretory granules (mean diameter, 257 nm), were considered to be the matured form of Type-I cells and the typical somatotropic cell-type, and were much more predominant than the Type-I cells. The fact that Type-II cells had a distinct Golgi zone and many mitochondria, while in Type-I cells the intracellular organelles were generally less developed, supports this suggestion. In addition to these two extreme subtypes, several intermediate forms were also encountered that may represent different transitional phases during the conversion of Type I to Type II. Protein A-gold immuno-electron microscopy illustrated the specific localization of growth hormone over the granules, with no labelling over any other cytoplasmic organelles of the 2 somatotrope subtypes. 相似文献
23.
C. Massault B. Hellemans B. Louro C. Batargias J. K. J. Van Houdt A. Canario F. A. M. Volckaert H. Bovenhuis C. Haley D. J. De Koning 《Animal genetics》2010,41(4):337-345
Natural mating and mass spawning in the European sea bass (Dicentrarchus labrax L., Moronidae, Teleostei) complicate genetic studies and the implementation of selective breeding schemes. We utilized a two‐step experimental design for detecting QTL in mass‐spawning species: 2122 offspring from natural mating between 57 parents (22 males, 34 females and one missing) phenotyped for body weight, eight morphometric traits and cortisol levels, had been previously assigned to parents based on genotypes of 31 DNA microsatellite markers. Five large full‐sib families (five sires and two dams) were selected from the offspring (570 animals), which were genotyped with 67 additional markers. A new genetic map was compiled, specific to our population, but based on the previously published map. QTL mapping was performed with two methods: half‐sib regression analysis (paternal and maternal) and variance component analysis accounting for all family relationships. Two significant QTL were found for body weight on linkage group 4 and 6, six significant QTL for morphometric traits on linkage groups 1B, 4, 6, 7, 15 and 23 and three suggestive QTL for stress response on linkage groups 3, 14 and 23. The QTL explained between 8% and 38% of phenotypic variance. The results are the first step towards identifying genes involved in economically important traits like body weight and stress response in European sea bass. 相似文献
24.
25.
《L'Anthropologie》2021,125(4):102923
The study is focused on comparative analysis of the five dwellings of the Anosov-Mezin type from the East-Epigravettian site of Yudinovo (Bryansk region, Russia). The analysis is based on data on previously unknown structural elements and methods of installation of mammoth skulls in the basement of dwelling No 5, which were revealed during excavations in 2015–2018. Apart of this the non-utilitarian actions that accompanied the process of dwellings construction was considered. Based on the revealed differences in structural elements and features, it was suggested that the currently used concept Anosovka-Mezin type of dwellings includes two types of the circular structures made of skulls and large mammoth bones. 相似文献
26.
C. B. Wadsworth W. A. Woods Jr D. A. Hahn E. B. Dopman 《Journal of evolutionary biology》2013,26(11):2359-2368
Evolutionary change in the timing of dormancy enables animals and plants to adapt to changing seasonal environments and can result in ecological speciation. Despite its clear biological importance, the mechanisms underlying the evolution of dormancy timing in animals remain poorly understood because of a lack of anatomical landmarks to discern which phase of dormancy an individual is experiencing. Taking advantage of the nearly universal characteristic of metabolic suppression during insect dormancy (diapause), we use patterns of respiratory metabolism to document physiological landmarks of dormancy and test which of the distinct phases of the dormancy developmental pathway contribute to a month‐long shift in diapause timing between a pair of incipient moth species. Here, we show that divergence in life cycle between the earlier‐emerging E‐strain and the later‐emerging Z‐strain of European corn borer (ECB) is clearly explained by a delay in the timing of the developmental transition from the diapause maintenance phase to the termination phase. Along with recent findings indicating that life‐cycle differences between ECB strains stem from allelic variation at a single sex‐linked locus, our results demonstrate how dramatic shifts in animal seasonality can result from simple developmental and genetic changes. Although characterizing the multiple phases of the diapause developmental programme in other locally adapted populations and species will undoubtedly yield surprises about the nature of animal dormancy, results in the ECB moth suggest that focusing on genetic variation in the timing of the dormancy termination phase may help explain how (or whether) organisms rapidly respond to global climate change, expand their ranges after accidental or managed introductions, undergo seasonal adaptation, or evolve into distinct species through allochronic isolation. 相似文献
27.
M. Skog A. Chandrapavan E. Hallberg T. Breithaupt 《Marine and Freshwater Behaviour and Physiology》2013,45(2):119-133
We studied the relevance of urine cues in Homarus gammarus dominance maintenance, hypothesising that urinary signals are necessary to mediate recognition of former opponents. Males in size-matched pairs interacted on two consecutive days with or without blocking urine release by adding catheters to both contestants on the second day. European lobsters established dominance in a first fight, and fight duration and aggression levels decreased strongly from first to second day in animals with free urine release, indicating the maintenance of this dominance relationship. If urine was blocked on the second day, fight durations were long in both first and second day interactions. Results demonstrate that urine signals contribute to the maintenance of dominance in H. gammarus males. 相似文献
28.
29.
《MABS-AUSTIN》2013,5(4):799-802
The commercial pipeline of monoclonal antibodies is highly dynamic, with a multitude of transitions occurring during the year as product candidates advance through the clinical phases and onto the market. The data presented here add to that provided in the extensive “Antibodies to watch in 2014” report published in the January/February 2014 issue of mAbs. Recent phase transition data suggest that 2014 may be a banner year for first approvals of antibody therapeutics. As of May 2014, three products, ramucirumab (Cyramza®), siltuximab (Sylvant®) and vedolizumab (EntyvioTM), had been granted first approvals in the United States, and four additional antibody therapeutics (secukinumab, dinutuximab, nivolumab, pembrolizumab) are undergoing regulatory review in either the US or the European Union. Other notable events include the start of first Phase 3 studies for seven antibody therapeutics (dupilumab, SA237, etrolizumab, MPDL3280A, bavituximab, clivatuzumab tetraxetan, blinatumomab). Relevant data for these product candidates are summarized, and metrics for antibody therapeutics development are discussed. 相似文献
30.
M. Zaccaroni N. Biliotti A. Buccianti S. Calieri M. Ferretti M. Genghini F. Riga V. Trocchi F. Dessì-Fulgheri 《Mammalian Biology》2013,78(6):482-485
In this study, activity patterns of the European hare (Lepus europaeus) were analyzed during winter using global positioning system (GPS) collars on 24 hares in two study areas located in central Italy. We programmed the collars to collect 12 location points per day, for a duration of three months. Results show two distinct phases of activities related to the day–night cycle. The daytime phase is characterized by inactivity at the form while the second phase is characterized by movements. Males were more active than females, showing a constant locomotor activity during the whole night. Females showed two peaks of activity during the night with a reduction in the middle of this time period. The comparison between females of the two study areas showed difference in interfix distance in particular around sunset and sunrise. In fact the minimum daily movement between the two areas shows that foraging sites of area B are more distant than those of area A. The recent possibility to apply GPS collars on small–medium mammals provides a powerful instrument to study the behavioral ecology of the European hare, and consequently promote an effective population management strategy for the species conservation. 相似文献