全文获取类型
收费全文 | 650篇 |
免费 | 42篇 |
出版年
2022年 | 16篇 |
2021年 | 13篇 |
2020年 | 11篇 |
2019年 | 16篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 31篇 |
2015年 | 24篇 |
2014年 | 35篇 |
2013年 | 43篇 |
2012年 | 45篇 |
2011年 | 38篇 |
2010年 | 33篇 |
2009年 | 24篇 |
2008年 | 48篇 |
2007年 | 43篇 |
2006年 | 28篇 |
2005年 | 25篇 |
2004年 | 19篇 |
2003年 | 19篇 |
2002年 | 15篇 |
2001年 | 20篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 8篇 |
1994年 | 3篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 6篇 |
1989年 | 10篇 |
1988年 | 3篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1965年 | 1篇 |
1964年 | 2篇 |
排序方式: 共有692条查询结果,搜索用时 375 毫秒
681.
Ana M. Valente Pelayo Acevedo Ana M. Figueiredo Carlos Fonseca Rita T. Torres 《Mammal Review》2020,50(4):353-366
- Throughout recent years, ungulates have experienced significant increases in numbers and geographic range sizes in Europe, becoming locally overabundant populations in some regions. Changes in legislation regarding poaching, abandonment of land and re-naturalisation of habitats, and decreasing numbers of hunters, among other things, have led to alarming scenarios in wild ungulate biology. Although ungulates bring some financial benefits for ecosystems and society through tourism and hunting, the problems associated with populations that are no longer controlled can outweigh the advantages. Damage to forestry and agriculture, ungulate-vehicle collisions, and diseases are among the most concerning problems related to ungulate overabundance.
- To deal with these problems and to decide on the best management strategy to apply, it is essential to have tools available to monitor populations with an integrative approach based on ecological change indicators, and to assess population and ecosystem status. Furthermore, in a globalised world, people’s opinions matter, and sociological studies regarding human perception of wild mammals must take place in order to allow proper management, including consideration of people’s expectations as well as animal and ecosystem needs. Successful and unsuccessful management strategies have already been attempted, and the knowledge of consequences over time enables an adaptive approach.
- Management of ungulate populations is a complex subject, and each case should be studied, analysing the cost_performance balance of measures to be taken, and ensuring ongoing financial means to carry out and continue with successful ecosystem management strategies. Multidisciplinary teams should be built, including biologists, veterinarians, stakeholders, sociologists, and others, to deal with the management of European wild ungulate populations.
682.
683.
In Vitro Activity of Melaleuca alternifolia (Tea Tree) in Its Free Oil and Nanoemulsion Formulations Against Pythium insidiosum 总被引:1,自引:0,他引:1
Júlia de Souza Silveira Valente Anelise de Oliveira da Silva Fonseca Carolina Litchina Brasil Lauren Sagave Fernanda Cramer Flores Cristiane de Bona da Silva Luís Antônio Sangioni Luciana Pötter Janio Morais Santurio Sônia de Avila Botton Daniela Isabel Brayer Pereira 《Mycopathologia》2016,181(11-12):865-869
684.
Alfredo Gusmão Cristina Valente Verónica Gomes Cíntia Alves António Amorim Maria João Prata Leonor Gusmão 《American journal of physical anthropology》2010,141(4):507-514
In this study, 123 unrelated Portuguese Gypsies were analyzed for 15 highly polymorphic autosomal short tandem repeats (STRs). Average gene diversity across the 15 markers was 76.7%, which is lower than that observed in the non‐Gypsy Portuguese population. Subsets of STRs were used to perform comparisons with other Gypsy and corresponding host populations. Interestingly, diversity reduction in Gypsy groups compared to their non‐Gypsy surrounding populations apparently varied according to an East‐West gradient, which parallels their dispersion in Europe as well as a decrease in complexity of their internal structure. Analysis of genetic distances revealed that the average level of genetic differentiation between Gypsy groups was much larger than that observed between the corresponding non‐Gypsy populations. The high rate of heterogeneity among Gypsies can be explained by strong genetic drift and limited intergroup gene flow. However, when genetic relationships were addressed through principal component analysis, all Gypsy populations clustered together and was clearly distinguished from other populations, a pattern that suggests their common origin. Concerning the putative ancestral genetic component, admixture analysis did not reveal strong Indian ancestry in the current Gypsy gene pools, in contrast to the high admixture estimates for either Europeans or Western Asians. Am J Phys Anthropol 2010. © 2009 Wiley‐Liss, Inc. 相似文献
685.
686.
687.
A. H. Moraes D. Ackerbauer M. Kostadinova M. Bublin F. Ferreira F. C. L. Almeida H. Breiteneder A. P. Valente 《Biomolecular NMR assignments》2013,7(2):133-136
Gad m 1 is the major allergen from Atlantic cod. It belongs to β-parvalbumin protein family and is characterized by the presence of two calcium-binding sites so called EF-hand motifs. β-Parvalbumins such as Gad m 1 are the most important fish allergens and their high cross-reactivity is the cause of the observed polysensitization to various fish species in allergic patients. Despite extensive efforts, the complete elucidation of β-parvalbumin-IgE complexes has not been achieved yet. Allergen structural studies are essential for the development of novel immunotherapy strategies, including vaccination with hypoallergenic derivatives and chimeric molecules. Here, we report for the first time the NMR study of a β-parvalbumin: Gad m 1. This report includes: 1H, 13C and 15N resonance assignments of Gad m 1 as well as the second structure information based on the 13C chemical shifts. 相似文献
688.
Domenica Musumeci Margherita Valente Domenica Capasso Rosanna Palumbo Matthias Grlach Michaela Schmidtke Roland Zell Giovanni N. Roviello Roberto Sapio Carlo Pedone Enrico M. Bucci 《Journal of peptide science》2006,12(3):161-170
Targeting regulatory RNA regions to interfere with the biosynthesis of a protein is an intriguing alternative to targeting a protein itself. Regulatory regions are often unique in sequence and/or structure and, thus, ideally suited for specific recognition with a low risk of undesired side effects. Targeting regulatory RNA elements, however, is complicated by their complex three-dimensional structure, which poses kinetic and thermodynamic constraints to the recognition by a complementary oligonucleotide. Oligonucleotide mimics, which shift the thermodynamic equilibrium towards complex formation and yield stable complexes with a target RNA, can overcome this problem. Peptide nucleic acids (PNA) represent such a promising class of molecules. PNA are very stable, non-ionic compounds and they are not sensitive to enzymatic degradation. Yet, PNA form specific base pairs with a target sequence. We have designed, synthesised and characterised PNA able to enter infected cells and to bind specifically to a control region of the genomic RNA of coxsackievirus B3 (CVB3), which is an important human pathogen. The results obtained by studying the interaction of such PNA with their RNA target, the entrance into the cell and the viral inhibition are herein presented. 相似文献
689.
690.
The cytologic findings in a case of disseminated histoplasmosis diagnosed by fine needle aspiration (FNA) of the adrenal gland are presented. Bilateral adrenal enlargement was discovered on CT scan in a patient whose systemic symptoms had been attributed to tuberculosis, but were resistant to antituberculous chemotherapy. The aspirate contained numerous histiocytes containing intracytoplasmic organisms with the morphologic features of Histoplasma capsulatum. The case shows that radiographically directed FNA of the adrenal gland, which has been recognized as a valuable aid in the confirmation of primary and secondary neoplasia, may also be quite useful in the less common setting of infectious disease involving this organ. 相似文献