全文获取类型
收费全文 | 5433篇 |
免费 | 313篇 |
国内免费 | 2篇 |
出版年
2024年 | 2篇 |
2023年 | 61篇 |
2022年 | 85篇 |
2021年 | 190篇 |
2020年 | 144篇 |
2019年 | 165篇 |
2018年 | 174篇 |
2017年 | 166篇 |
2016年 | 267篇 |
2015年 | 348篇 |
2014年 | 322篇 |
2013年 | 417篇 |
2012年 | 482篇 |
2011年 | 438篇 |
2010年 | 300篇 |
2009年 | 222篇 |
2008年 | 315篇 |
2007年 | 312篇 |
2006年 | 269篇 |
2005年 | 231篇 |
2004年 | 198篇 |
2003年 | 195篇 |
2002年 | 167篇 |
2001年 | 30篇 |
2000年 | 36篇 |
1999年 | 28篇 |
1998年 | 36篇 |
1997年 | 22篇 |
1996年 | 21篇 |
1995年 | 16篇 |
1994年 | 15篇 |
1993年 | 9篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 11篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1967年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有5748条查询结果,搜索用时 448 毫秒
951.
Marcelo Leandro Bueno Vanessa Leite Rezende Vanessa Pontara Ary Teixeira de Oliveira-Filho 《Plant Ecology》2017,218(10):1171-1186
The Paraguayan territory and region, in the centre of South America, is a huge transition area with a succession of various vegetation types. However, this area has received little attention from researchers, with few works published on its flora and its delimitations. We aimed to identify the most important environmental driving forces and delimit floristic patterns in this region, since understanding the forces that drive floristic variations in this ecotonal region could help comprehend the distribution of vegetation not only in this region but throughout South America. We obtained 1234 tree species occurrence records, 205 geographic coordinates and 23 environmental variables and altitude from the ‘NeoTropTree’ database and verified the influence and contribution of environmental factors through variance partition. We tested the floristic consistency of the different vegetation types using dendrogram, indicator species and ordination analyses. We also constructed multiple linear models to check the correlation between species distribution and environmental variables. We found eight consistent vegetation types. The spatial variables coupled with environmental variables were more important than individual environmental or spatial variables. Among the environmental variables, the aridity index was the most important. Despite the importance of spatial factors, due to environmental heterogeneity, we found a gradient related to climate and edaphic variables related to tree flora. The results confirm that the Paraguayan territory and region can be considered to be a diversified and important ecotone area in South America with respect to tree flora. 相似文献
952.
Clarissa Alves da Rosa Nelson Henrique de Almeida Curi Fernando Puertas Marcelo Passamani 《Biological invasions》2017,19(7):2101-2123
The invasion of alien species is an important cause of biodiversity loss worldwide, and many mammals are considered successful invaders outside their former range, with recognized detrimental effects to native ecosystems. Our aim was to review the current literature on alien mammals that have established feral populations in Brazil and to systematize the existing knowledge. Furthermore, we evaluated the current distributions of all invasion mammals and discuss different management actions, including eradication techniques for island populations. We found 17 species of alien mammals living in the wild in Brazil. Based on the current literature and databases regarding invasive species, Lepus europaeus and Sus scrofa had the largest distributions in the Brazilian territory and seem to continue expanding their geographic distributions. Feral dogs and cats were the main alien predators threatening wildlife conservation, especially in protected areas. Further, we call attention to the invasion of Bubalus bubalis, a large species that currently thrives in isolated populations but seems to be quickly expanding its distribution. In conclusion, alien mammals are widespread in Southern and Southeastern Brazil, but at least four ungulate species (Indian sambar, horse, goat, and axis deer) still have small and isolated populations. Finally, future efforts need to evaluate the impacts of alien mammals in Brazil and techniques for their control. 相似文献
953.
Marcelo Piaia Carolina Bonet Bub Guilherme de Menezes Succi Margareth Torres Thiago Henrique Costa Fabricio Costa Pinheiro Marcelo Henrique Napimoga 《Cell and tissue banking》2017,18(1):75-81
According to the Brazilian Association of Organ Transplants, in 2015, 19,408 bone transplants were performed in Brazil, over 90% by Dental Surgeons. The surgical technique itself has a respectable number of reports regarding its clinical efficacy, as measured by long-term survival of dental implants in grafted areas. Uncertainty remains, however, as to whether fresh frozen grafts from human bone donors remain immunologically innocuous in the body of the host. Six male with no previous medical history of note, including systemic diseases, surgery or blood transfusion were selected. These patients underwent reconstructive procedures (sinus lifting) using fresh frozen human bone from a tissue bank. All patients had venous blood samples collected prior to surgery and 6 months after the procedure. Anti-HLA analysis for the detection of HLA (human leukocyte antigen) antibodies was performed using methods such as the LABScreen PRA Class I and Class II, LABScreen Single Antigen Class I and Class II, Luminex Platform. Reactive individuals to the screening tests (LABScreen PRA) were further investigated to determine the specificity of the antibodies detected (LABScreen Single Antigen) with a cutoff value of median fluorescence intensity ≥500. As a result, it was observed that two patients (33%) were positive in screening tests, one presenting with anti-HLA Class I and II sensitization and the other with anti-HLA class II. The specificity analysis showed that the patients sensitized to HLA class II presented 4 specificities, 3 of which immunologically relevant. In the second individual, 23 specificities were identified, 6 of which immunologically important for HLA class I and 4 specificities for HLA class II, 3 of these were immunologically important. All specificities detected had average fluorescence. These findings are suggestive that sinus-lifting procedures with allogeneic bone can induce immunological sensitization. 相似文献
954.
Genome‐wide transcriptome analysis of Aspergillus fumigatus exposed to osmotic stress reveals regulators of osmotic and cell wall stresses that are SakAHOG1 and MpkC dependent
下载免费PDF全文
![点击此处可从《Cellular microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
955.
956.
957.
Weerayuth Supiwong Thomas Liehr Marcelo B. Cioffi Arunrat Chaveerach Nadezda Kosyakova Krit Pinthong Tawatchai Tanee Alongklod Tanomtong 《Zoologischer Anzeiger》2014
We analyzed the distribution of repetitive DNA sequences on the chromosomes of nine species of the Bagridae from Thailand, i.e., Hemibagrus filamentus; H. nemurus; H. wyckii; H. wyckioides; Mystus atrifasciatus; M. multiradiatus; M. mysticetus; M. bocourti and Pseudomystus siamensis. Two classes of microsatellites and one transposable element (TE) were mapped by fluorescence in situ hybridization. The distribution of the repetitive sequences was comparatively analyzed in view to investigate their contribution in the chromosomal evolution of this fish group. In all species the microsatellites (CA)15 and (GA)15 are abundantly distributed in all chromosomes, usually in the telomeric regions. The retrotransposable element Rex 1 is widely distributed over the whole genome including heterochromatin and euchromatin, but with an unexpected accumulation in one chromosome pair in some species. In fact, some species–specific patterns could be observed considering both microsatellites and TE distribution. The results demonstrated that the compartmentalization of repeated elements is not simply restricted to heterochromatic regions, as it has been postulated in the first concepts of the genomic organization of repetitive elements in genomes. Moreover, the organization of these repeats seems to reflect their intense and specific evolutionary pathway, providing new insights about the chromosomal evolution in the Bagridae. 相似文献
958.
959.
Tatiane A. Paixão Marcelo C. C. Malta Semíramis A. Soave Herlandes P. Tinoco Maria E.L.T. Costa Angela T. Pessanha Rodrigo O.S. Silva Fernanda M. Coura Luciana F. Costa Andreia P. Turchetti Francisco C.F. Lobato Marilia M. Melo Marcos B. Heinemann Renato L. Santos 《Journal of medical primatology》2014,43(2):118-121
960.
Laura Azeredo Miranda Mota Jo?o Roberto Neto Ver?nica Gomes Monteiro Caroliny Samary Silva Lobato Marco Antonio de Oliveira Maura da Cunha Heloisa D’ávila Sérgio Henrique Seabra Patrícia Torres Bozza Renato Augusto DaMatta 《Memórias do Instituto Oswaldo Cruz》2014,109(6):767-774
Lipid bodies [lipid droplets (LBs)] are lipid-rich organelles involved in lipid
metabolism, signalling and inflammation. Recent findings suggest a role for LBs in
host response to infection; however, the potential functions of this organelle
in Toxoplasma gondii infection and how it alters macrophage
microbicidal capacity during infection are not well understood. Here, we investigated
the role of host LBs in T. gondii infection in mouse peritoneal
macrophages in vitro. Macrophages cultured with mouse serum (MS) had higher numbers
of LBs than those cultured in foetal bovine serum and can function as a model to
study the role of LBs during intracellular pathogen infection. LBs were found in
association with the parasitophorous vacuole, suggesting that T. gondii
may benefit from this lipid source. Moreover, increased numbers of
macrophage LBs correlated with high prostaglandin E2 (PGE2) production and decreased
nitric oxide (NO) synthesis. Accordingly, LB-enriched macrophages cultured with MS
were less efficient at controlling T. gondii growth. Treatment of
macrophages cultured with MS with indomethacin, an inhibitor of PGE2 production,
increased the microbicidal capacity against T. gondii. Collectively,
these results suggest that culture with MS caused a decrease in microbicidal activity
of macrophages against T. gondii by increasing PGE2 while lowering
NO production. 相似文献