全文获取类型
收费全文 | 1048篇 |
免费 | 85篇 |
出版年
2023年 | 6篇 |
2022年 | 8篇 |
2021年 | 25篇 |
2020年 | 14篇 |
2019年 | 12篇 |
2018年 | 19篇 |
2017年 | 25篇 |
2016年 | 30篇 |
2015年 | 41篇 |
2014年 | 57篇 |
2013年 | 52篇 |
2012年 | 90篇 |
2011年 | 74篇 |
2010年 | 49篇 |
2009年 | 31篇 |
2008年 | 50篇 |
2007年 | 38篇 |
2006年 | 62篇 |
2005年 | 50篇 |
2004年 | 33篇 |
2003年 | 36篇 |
2002年 | 42篇 |
2001年 | 20篇 |
2000年 | 23篇 |
1999年 | 15篇 |
1998年 | 13篇 |
1997年 | 12篇 |
1996年 | 12篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 9篇 |
1991年 | 13篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 13篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1974年 | 8篇 |
1973年 | 5篇 |
1968年 | 4篇 |
1967年 | 8篇 |
排序方式: 共有1133条查询结果,搜索用时 15 毫秒
81.
Marcelo De Franco Patrícia dos Santos Carneiro Luciana Carla Peters Francisca Vorraro Andrea Borrego Orlando Garcia Ribeiro Nancy Starobinas Wafa Koury Cabrera Olga Martinez Ibañez 《Mammalian genome》2007,18(4):263-269
Lines of mice were obtained by selective breeding for maximum (AIRmax) or minimum (AIRmin) acute inflammation. They present
distinct neutrophil influx and show frequency disequilibrium of the solute carrier family 11a member 1
(Slc11a1) alleles. This gene is involved in ion transport at the endosomes within macrophages and neutrophils, interfering in their
activation. Homozygous AIRmax and AIRmin sublines for the Slc11a1 gene were produced to examine the interaction of this gene with the acute inflammatory loci. The present work investigated
wound-healing traits in AIRmax and AIRmin mice, in F1 and F2 intercrosses, and in Slc11a1 sublines. Two-millimeter ear punches were made in the mice and hole closure was measured during 40 days. AIRmax mice demonstrated
significant tissue repair while AIRmin mice did not. Significant differences between the responses of male and female mice
were also observed. Wound-healing traits demonstrated a correlation with neutrophil influx in F2 populations. AIRmax
SS
showed higher ear-wound closure than AIRmax
RR
mice, suggesting that the Slc11a1
S allele favored ear tissue repair. QTL analysis has detected two inflammatory loci modulating ear wound healing on chromosomes
1 and 14. These results suggest the involvement of the acute inflammation modifier QTL in the wound-healing phenotype. 相似文献
82.
Levasseur A Orlando L Bailly X Milinkovitch MC Danchin EG Pontarotti P 《Biological reviews of the Cambridge Philosophical Society》2007,82(4):551-572
To demonstrate that a given change in the environment has contributed to the emergence of a given genotypic and phenotypic shift during the course of evolution, one should ask to what extent such shifts would have occurred without environmental change. Of course, such tests are rarely practical but phenotypic novelties can still be correlated to genomic shifts in response to environmental changes if enough information is available. We surveyed and re-evaluated the published data in order to estimate the role of environmental changes on the course of species and genomic evolution. Only a few published examples clearly demonstrate a causal link between a given environmental change and the fixation of a genomic variant resulting in functional modification (gain, loss or alteration of function). Many others suggested a link between a given phenotypic shift and a given environmental change but failed to identify the underlying genomic determinant(s) and/or the associated functional consequence(s). The proportion of genotypic and phenotypic variation that is fixed concomitantly with environmental changes is often considered adaptive and hence, the result of positive selection, even though alternative causes, such as genetic drift, are rarely investigated. Therefore, the second aim herein is to review evidence for the mechanisms leading to fixation. 相似文献
83.
84.
85.
New insights to discriminate between Sympterygia acuta Garman 1877 and Sympterygia bonapartii Müller & Henle, 1841 (Rajidae) of the Southwest Atlantic Ocean: on the use of geometric morphometrics and spinulation patterns 下载免费PDF全文
P. Orlando M. González‐Castro E. Mabragaña 《Zeitschrift fur angewandte Ichthyologie》2015,31(2):381-389
Geometric‐morphometric and spinulation pattern approaches were employed to assess the discrimination of two species of Sympterygia skates in the Southwest Atlantic: Sympterygia acuta Garman 1877 and Sympterygia bonapartii Müller & Henle, 1841. Two types of variables were employed: linear morphometrics measurements (LMMs), and interlandmark distances (IlDs). The Principal Component Analysis (PCA) and the discriminant analysis (DA) do not overlap between the species. Morphometrically, S. bonapartii is characterized by a wider disc, larger pelvic fins, larger eyes, a greater distance between nostrils and between the first pair of gill slits, a greater interorbital distance between spiracles, and a wider mouth. On the other hand, S. acuta has a larger disc due to the snout size. Regarding the allometric coefficient analysis performed on the IlDs, S. bonapartii showed a positive allometry for the variables that comprise the Box‐Truss 3 (Ventral protocol), which can be related to the mouth width and the first gill slits. This growth type is consistent with those observed in the Box‐Truss 3 (Outline protocol), which is related to the disc width. It has been interpreted that both structures could develop together. In opposition, S. acuta showed isometric growth for the above‐mentioned variables; on the other hand, S. acuta showed positive allometry for all variables that defined the snout in the three protocols, indicating that the snout has a distinctive growth relative to the size through ontogeny. S. bonapartii, however, showed an isometric snout growth. The remaining variables that defined the morphogeometrical protocols displayed the same type of growth. Regarding spinulation, the thorns and dermal denticles proved to be useful to discriminate both species. Thorns of the caudal region were large and oval with smooth edges in S. bonapartii, and oval with lobed edges in S. acuta. Dermal denticles in S. acuta also presented two elongated ridges with a third small ridge between them, whereas those of S. bonapartii presented three elongated ridges of the same size. 相似文献
86.
R Gon?alves LA Szmuchrowski LS Prado BP Couto JCQ Machado VO Damasceno JA Lamounier 《Biology of sport / Institute of Sport》2015,32(3):255-260
The aim of this study was to assess the suitability of body mass index, waist circumference, waist-to-height ratio and aerobic fitness as predictors of cardiovascular risk factor clustering in children. A cross-sectional study was conducted with 290 school boys and girls from 6 to 10 years old, randomly selected. Blood was collected after a 12-hour fasting period. Blood pressure, waist circumference (WC), height and weight were evaluated according to international standards. Aerobic fitness (AF) was assessed by the 20-metre shuttle-run test. Clustering was considered when three of these factors were present: high systolic or diastolic blood pressure, high low-density lipoprotein (LDL) cholesterol, high triglycerides, high plasma glucose, high insulin concentrations and low high-density lipoprotein (HDL) cholesterol. A ROC curve identified the cut-off points of body mass index (BMI), WC, waist-to-height ratio (WHtR) and AF as predictors of risk factor clustering. BMI, WC and WHR resulted in significant areas under the ROC curves, which was not observed for AF. The anthropometric variables were good predictors of cardiovascular risk factor clustering in both sexes, whereas aerobic fitness should not be used to identify cardiovascular risk factor clustering in these children. 相似文献
87.
Fernanda S. Freitas Orlando C. De‐Paula Jimi N. Nakajima Juliana Marzinek 《Botanical journal of the Linnean Society. Linnean Society of London》2015,179(2):255-265
Heterocoma is a Brazilian endemic genus resulting from the dismemberment of Sipolisiinae, in which only representatives with fruit containing phytomelanin were included in the genus. As the fruits of Asteraceae are known to be systematically important at various taxonomic levels and Heterocoma fruit has not been described previously, we studied the morphology and anatomy of the cypselas of all species of the genus, comparing them with other fruits in the family containing phytomelanin and evaluating the systematic potential at the specific and tribal levels. The fruits were analysed by scanning electron microscopy (SEM) and light microscopy. The morphological features of the fruit, including the carpopodium, ribs and pappi, varied in the genus and demonstrated potential for species discrimination. The anatomy showed a pattern for the genus with a uniseriate exocarp, the outer mesocarp composed of fibres arranged in several layers, the inner mesocarp composed of several layers of parenchyma, the endocarp, and phytomelanin deposited between the inner and outer mesocarp. This anatomical pattern of phytomelanin deposition differs from that of other Asteraceae with phytomelanin in their fruit. Heterocoma is also the only genus in Vernonieae that has phytomelanin deposition in the cypselas. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 255–265. 相似文献
88.
89.
David Gendron Anne-Marie Lemay Claudine Tremblay Laetitia JA Lai Anick Langlois émilie Bernatchez Nicolas Flamand Marie-Renée Blanchet Anthony S Don Ynuk Bossé élyse Bissonnette David Marsolais 《Respiratory research》2015,16(1)
Background
In vivo phosphorylation of sphingosine analogs with their ensuing binding and activation of their cell-surface sphingosine-1-phosphate receptors is regarded as the main immunomodulatory mechanism of this new class of drugs. Prophylactic treatment with sphingosine analogs interferes with experimental asthma by impeding the migration of dendritic cells to draining lymph nodes. However, whether these drugs can also alleviate allergic airway inflammation after its onset remains to be determined. Herein, we investigated to which extent and by which mechanisms the sphingosine analog AAL-R interferes with key features of asthma in a murine model during ongoing allergic inflammation induced by Dermatophagoides pteronyssinus.Methods
BALB/c mice were exposed to either D. pteronyssinus or saline, intranasally, once-daily for 10 consecutive days. Mice were treated intratracheally with either AAL-R, its pre-phosphorylated form AFD-R, or the vehicle before every allergen challenge over the last four days, i.e. after the onset of allergic airway inflammation. On day 11, airway responsiveness to methacholine was measured; inflammatory cells and cytokines were quantified in the airways; and the numbers and/or viability of T cells, B cells and dendritic cells were assessed in the lungs and draining lymph nodes.Results
AAL-R decreased airway hyperresponsiveness induced by D. pteronyssinus by nearly 70%. This was associated with a strong reduction of IL-5 and IL-13 levels in the airways and with a decreased eosinophilic response. Notably, the lung CD4+ T cells were almost entirely eliminated by AAL-R, which concurred with enhanced apoptosis/necrosis in that cell population. This inhibition occurred in the absence of dendritic cell number modulation in draining lymph nodes. On the other hand, the pre-phosphorylated form AFD-R, which preferentially acts on cell-surface sphingosine-1-phosphate receptors, was relatively impotent at enhancing cell death, which led to a less efficient control of T cell and eosinophil responses in the lungs.Conclusion
Airway delivery of the non-phosphorylated sphingosine analog, but not its pre-phosphorylated counterpart, is highly efficient at controlling the local T cell response after the onset of allergic airway inflammation. The mechanism appears to involve local induction of lymphocyte apoptosis/necrosis, while mildly affecting dendritic cell and T cell accumulation in draining lymph nodes. 相似文献90.
Lucélia Santi Lucas André Dedavid e Silva Walter Orlando Beys da Silva Ana Paula Folmer Corrêa Drauzio Eduardo Naretto Rangel Célia Regina Carlini Augusto Schrank Marilene Henning Vainstein 《World journal of microbiology & biotechnology》2011,27(10):2297-2303
The cotton stainer bug Dysdercus peruvianus (Hemiptera: Pyrrhocoridae) is an insect pest that causes heavy losses in cotton plantations. The need to reduce the use of insecticides for control of this pest has increased steadily, and Metarhizium anisopliae (Ascomycota: Clavicipitaceae) could be an important biopesticide candidate to control this pest. The effect of M. anisopliae on D. peruvianus nymphs and adults using formulations with soybean oil and Agral® was evaluated. Formulation using 10% soybean oil added to 108 conidia mL?1 (grown on used and reused rice) was the most effective for nymph and adult, causing 100% mortality 6 and 7 days after exposure, respectively. The SEM analysis of infected insects showed that M. anisopliae conidia were able to adhere anywhere on the exoskeleton, but were more abundant between the joints. Using the same rice for two batches of growth may be an option for improving commercial conidial production of M. anisopliae and may reduce overall costs. Its effect on D. peruvianus adults opens a new possibility for using this fungus as an alternative to chemical pesticides and the use of M. anisopliae in association with integrate pest management. 相似文献