全文获取类型
收费全文 | 81篇 |
免费 | 5篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2019年 | 2篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 3篇 |
2013年 | 10篇 |
2012年 | 5篇 |
2011年 | 2篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 1篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1990年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有86条查询结果,搜索用时 203 毫秒
71.
Six Costa Rican communities of different ecological settings were selected for the study of food intake in children under 5 years of age. Intake was expressed as calorie and protein adequacy. Calorie deficiency was more prevalent than protein defficiency. Practically there were no differences in adequacy by age, although 4 year-olds had a slightly greater deficiency than observed in a relatively more advanced rural region 4 years earlier. Only 13 per cent of the children selected at random were covered by Social Development and Family Allowances programs which provide for two "hot meals" per day. Calorie deficiencies of children benefiting from this program were of similar magnitude as those of children not attending the food distribution centers. These observations point to the need to carry out further investigation of the actual effectiveness and drawbacks of such programs. 相似文献
72.
Chase D. Mendenhall Cagan H. Sekercioglu Federico Oviedo Brenes 《Journal of Field Ornithology》2010,81(1):49-63
ABSTRACT Field methods for determining the sex of birds are often limited due to morphometric overlap between sexes, intermediate plumages, seasonality, and reliance on subjective age classification. Interpubic distance, characterized in birds as the distance between the distal ends of the pubic bones, has not been formally tested as a method for determining the sex of birds, despite references among parrot breeders and the frequent use of analogous measurements in mammals. We developed a harmless and easily performed field method for measuring interpubic distance in studies involving bird capture, and compared the interpubic distances of known sex White‐ruffed Manakins (Corapipo altera), Orange‐collared Manakins (Manacus aurantiacus), and Blue‐crowned Manakins (Lepidothrix coronata) to evaluate the possible use of this measurement to determine sex. Using interpubic distance ranges based on 85% confidence intervals where overlap existed between sexes, the sex of 92.8–100% of all manakins in our study was accurately determined with no misclassification. Interpubic distance performed better than plumage‐based methods that sexed 74.0% of all individuals and misclassified 1.5%. Using linear discriminant analysis, we developed classification equations that allowed us to accurately determine the sex of all individuals with 100% accuracy using mass and interpubic distance. Additionally, we compared the interpubic distances of female White‐ruffed Manakins to evaluate the potential to determine age and reproductive status. Despite an apparent relationship between interpubic distance, age and reproductive status, we concluded that interpubic distance has limited use for determining age and reproductive status due to extensive overlap (31.6–100%), but shows potential in other applications. Based on these results, we endorse the use of interpubic distance to determine the sex of manakins. We encourage further study to develop additional classification equations using different morphometric measurements and to test the efficacy of interpubic distance to determine sex in other bird species. 相似文献
73.
74.
75.
Dott. CL. CH. Mathon 《Plant biosystems》2013,147(2-3):345-356
Resumé Chez les Blés branchus de l'espèce «turgidum» (Triticum turgidum compositum), il existe des sortes à thermostade plutôt froid (Blés d'hiver ou de semi-hiver) et des sortes à thermostade chaud, tièe ou «indifférent» (Blés de printemps). Les Blés branchus de l'espèce «turgidum» apparaissent comme étant des plantes à photostade de jour long. La plus ou moins grande rapidité de l'accomplissement du photostade, par rapport à la rapidité de l'assimilation des matières plastiques, détermine la structure, — non ramifiée ou ramifiée — de l'épi. 相似文献
76.
SGO1 but not SGO2 is required for maintenance of centromere cohesion in Arabidopsis thaliana meiosis
L. Zamariola N. De Storme CL. Tiang S. J. Armstrong F. C. H. Franklin D. Geelen 《Sexual plant reproduction》2013,26(3):197-208
Shugoshin is a protein conserved in eukaryotes and protects sister chromatid cohesion at centromeres in meiosis. In our study, we identified the homologs of SGO1 and SGO2 in Arabidopsis thaliana. We show that AtSGO1 is necessary for the maintenance of centromere cohesion in meiosis I since atsgo1 mutants display premature separation of sister chromatids starting from anaphase I. Furthermore, we show that the localization of the specific centromeric cohesin AtSYN1 is not affected in atsgo1, suggesting that SGO1 centromere cohesion maintenance is not mediated by protection of SYN1 from cleavage. Finally, we show that AtSGO2 is dispensable for both meiotic and mitotic cell progression in Arabidopsis. 相似文献
77.
78.
Survey of Malassezia sp and dermatophytes in the cutaneous microbiome of free‐ranging golden‐headed lion tamarins (Leontopithecus chrysomelas ‐ Kuhl, 1820)
下载免费PDF全文
![点击此处可从《Journal of medical primatology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
79.
80.
A lyophilized aqueous leaf extract of Cecropia obtusifolia proved to be antihypertensive when intravenously administrated to conscious spontaneous hypertensive rats. Forty-five minutes after injection, the maximum fall in arterial pressure (-23.5% relative to preinjection values) was seen and recovery was not complete by the end of the 180 min observation period. The extract was also given to pre-hypertensive SHR and normotensive rats. The fall in blood pressure was more conspicuous in the two SHr groups and was not accompanied by changes in cardiac frequency in any group. This would appear to rule out either a direct or indirect involvement of the heart in regard to the observed hypotension. 相似文献