全文获取类型
收费全文 | 368篇 |
免费 | 44篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 10篇 |
2016年 | 15篇 |
2015年 | 21篇 |
2014年 | 19篇 |
2013年 | 25篇 |
2012年 | 30篇 |
2011年 | 19篇 |
2010年 | 26篇 |
2009年 | 14篇 |
2008年 | 21篇 |
2007年 | 35篇 |
2006年 | 24篇 |
2005年 | 17篇 |
2004年 | 17篇 |
2003年 | 10篇 |
2002年 | 1篇 |
2001年 | 12篇 |
2000年 | 15篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1972年 | 2篇 |
1966年 | 1篇 |
1965年 | 2篇 |
排序方式: 共有412条查询结果,搜索用时 140 毫秒
51.
M Porta J Pumarega L Guarner N Malats R Solà FX Real;for the PANKRAS II Study Group 《Biomarkers》2012,17(6):557-565
We analyzed relationships of hepatic and pancreatic biomarkers with the cholestatic syndrome and tumor stage in exocrine pancreatic cancer (N = 183). Information on laboratory tests and on signs and symptoms was obtained from medical records and patient interviews. Bilirubin, aspartate aminotransferase (AST), γ-glutamyltransferase (GGT) and alkaline phosphatase were lower in tumor stage IV. The association was due to the relationship between cholestatic syndrome and earlier presentation of patients. There was no association between hepatic biomarkers and stage when adjusting by cholestatic syndrome. Relationships of hepatic and pancreatic biomarkers with pancreatic symptoms and tumor stage must be controlled in "-omics" and other studies using biomarkers. 相似文献
52.
Matesanz F González-Pérez A Lucas M Sanna S Gayán J Urcelay E Zara I Pitzalis M Cavanillas ML Arroyo R Zoledziewska M Marrosu M Fernández O Leyva L Alcina A Fedetz M Moreno-Rey C Velasco J Real LM Ruiz-Peña JL Cucca F Ruiz A Izquierdo G 《PloS one》2012,7(5):e36140
Multiple Sclerosis (MS) is the most common progressive and disabling neurological condition affecting young adults in the world today. From a genetic point of view, MS is a complex disorder resulting from the combination of genetic and non-genetic factors. We aimed to identify previously unidentified loci conducting a new GWAS of Multiple Sclerosis (MS) in a sample of 296 MS cases and 801 controls from the Spanish population. Meta-analysis of our data in combination with previous GWAS was done. A total of 17 GWAS-significant SNPs, corresponding to three different loci were identified:HLA, IL2RA, and 5p13.1. All three have been previously reported as GWAS-significant. We confirmed our observation in 5p13.1 for rs9292777 using two additional independent Spanish samples to make a total of 4912 MS cases and 7498 controls (ORpooled = 0.84; 95%CI: 0.80-0.89; p = 1.36 × 10-9). This SNP differs from the one reported within this locus in a recent GWAS. Although it is unclear whether both signals are tapping the same genetic association, it seems clear that this locus plays an important role in the pathogenesis of MS. 相似文献
53.
Marcos G Godoy Alejandra Aedo Molly JT Kibenge David B Groman Carmencita V Yason Horts Grothusen Angelica Lisperguer Marlene Calbucura Fernando Avendaño Marcelo Imilán Miguel Jarpa Frederick SB Kibenge 《BMC veterinary research》2008,4(1):1-13
Background
Several forms of progressive retinal atrophy (PRA) segregate in more than 100 breeds of dog with each PRA segregating in one or a few breeds. This breed specificity may be accounted for by founder effects and genetic drift, which have reduced the genetic heterogeneity of each breed, thereby facilitating the identification of causal mutations. We report here a new form of PRA segregating in the Border Collie breed. The clinical signs, including the loss of night vision and a progressive loss of day vision, resulting in complete blindness, occur at the age of three to four years and may be detected earlier through systematic ocular fundus examination and electroretinography (ERG). 相似文献54.
José C. Báez Raimundo Real J. Mario Vargas Antonio Flores-Moya 《Phycological Research》2005,53(4):255-265
The aim of the present paper is to identify the possible existence of groups of species in the genera Audouinella (Rhodophyta), Cystoseira (Phaeophyceae) and Cladophora (Chloropyta) with significantly similar distribution patterns (chorotypes), in the western Mediterranean Sea and the Adriatic Sea. Of the 98 species studied, 59 were grouped into 11 chorotypes, whereas 39 species remained ungrouped. Thirty‐eight species were included in a generalist chorotype, whereas 6 chorotypes were monospecific. The relationships with the environmental factors that could explain the chorotypes are discussed. 相似文献
55.
Dependence of broad-scale geographical variation in fleshy-fruited plant species richness on disperser bird species richness 总被引:1,自引:0,他引:1
Aim We analysed the interdependence of avian frugivore‐ and fruited plant‐species richness at the scale of major river basins across Europe, taking into account several environmental factors along different spatial gradients. Location Continental Europe and the British Isles. Methods We focused on wintering birds and autumn/winter fruiting plants, and used major river basins as geographical units and Structural Equation Modelling as the principal analytical tool. Results The statistical influence of disperser species richness on fleshy‐fruited plant species richness is roughly double that of the reverse. Broad‐scale variation in frugivore richness is more dependent on environmental factors than on fruited plant richness. However, the influence of disperser richness on plant richness is four times higher than the influence of environmental factors. Environmental influences on both birds and plants are greater than purely spatial influences. Main conclusions Our results are interpreted as indicating that biotic dispersal of fruits strongly affects broad‐scale geographical trends of fleshy‐fruited plant species richness, whereas richness of fruited plants moderately affects frugivore richness. 相似文献
56.
Farfán Miguel A. Vargas Juan M. Real Raimundo Palomo Luis J. Duarte Jesús 《Acta theriologica》2004,49(3):319-335
To analyse the population structure and reproductive biology of the Iberian hareLepus granatensis Rosenhauer, 1856, 498 hares (264 males and 234 females) were collected in monthly samples from October 1998 to September
1999. Females reached larger sizes than males, with approximately 400 g difference in body mass on reaching sexual maturity.
The total sex ratio was 1∶1, with a bias in favour of males in winter. Sexually active males and females appeared in every
month but August, when no sexually active female was found. Births occurred in every month and were more frequent between
March and July. Seasonal variation in kidney fat index (KFI) followed a similar pattern in males and females, with an increase
in mid-autumn and a decline at the end of winter. Reproductive activity appeared in every month, with a maximum from February
to June. Reproductively hyperactive females (simultaneously pregnant and nursing) appeared in every month except in January,
with a first peak in March and a second lower peak in May–June. Litter size fluctuated between 1 and 7 leverets. The most
frequent gestations involved 1 or 2 foetuses. The mean annual litter size was 2.08 and the average number of litters per productive
female per year was estimated to be 3.48. The maximum productivity was recorded between March and May. The total annual production
of young per adult female was estimated to be 7.21. The minimum annual survival rate of young was 27.91%. On the basis of
these results we propose to maintain the limit of the hunting period between October and December. We discuss the relationship
between the low young/adult ratio obtained and the hunting method used. 相似文献
57.
Identification of Genotypic Changes in Human Immunodeficiency Virus Protease That Correlate with Reduced Susceptibility to the Protease Inhibitor Lopinavir among Viral Isolates from Protease Inhibitor-Experienced Patients
下载免费PDF全文
![点击此处可从《Journal of virology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dale J. Kempf Jeffrey D. Isaacson Martin S. King Scott C. Brun Yi Xu Kathryn Real Barry M. Bernstein Anthony J. Japour Eugene Sun Richard A. Rode 《Journal of virology》2001,75(16):7462-7469
The association of genotypic changes in human immunodeficiency virus (HIV) protease with reduced in vitro susceptibility to the new protease inhibitor lopinavir (previously ABT-378) was explored using a panel of viral isolates from subjects failing therapy with other protease inhibitors. Two statistical tests showed that specific mutations at 11 amino acid positions in protease (L10F/I/R/V, K20M/R, L24I, M46I/L, F53L, I54L/T/V, L63P, A71I/L/T/V, V82A/F/T, I84V, and L90M) were associated with reduced susceptibility. Mutations at positions 82, 54, 10, 63, 71, and 84 were most closely associated with relatively modest (4- and 10-fold) changes in phenotype, while the K20M/R and F53L mutations, in conjunction with multiple other mutations, were associated with >20- and >40-fold-reduced susceptibility, respectively. The median 50% inhibitory concentrations (IC(50)) of lopinavir against isolates with 0 to 3, 4 or 5, 6 or 7, and 8 to 10 of the above 11 mutations were 0.8-, 2.7-, 13.5-, and 44.0-fold higher, respectively, than the IC(50) against wild-type HIV. On average, the IC(50) of lopinavir increased by 1.74-fold per mutation in isolates containing three or more mutations. Each of the 16 viruses that displayed a >20-fold change in susceptibility contained mutations at residues 10, 54, 63, and 82 and/or 84, along with a median of three mutations at residues 20, 24, 46, 53, 71, and 90. The number of protease mutations from the 11 identified in these analyses (the lopinavir mutation score) may be useful for the interpretation of HIV genotypic resistance testing with respect to lopinavir-ritonavir (Kaletra) regimens and may provide insight into the genetic barrier to resistance to lopinavir-ritonavir in both antiretroviral therapy-naive and protease inhibitor-experienced patients. 相似文献
58.
Selection of Specific Endophytic Bacterial Genotypes by Plants in Response to Soil Contamination 总被引:10,自引:2,他引:8
下载免费PDF全文
![点击此处可从《Applied microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Steven D. Siciliano Nathalie Fortin Anca Mihoc Gesine Wisse Suzanne Labelle Danielle Beaumier Danielle Ouellette Real Roy Lyle G. Whyte M. Kathy Banks Paul Schwab Ken Lee Charles W. Greer 《Applied microbiology》2001,67(6):2469-2475
Plant-bacterial combinations can increase contaminant degradation in the rhizosphere, but the role played by indigenous root-associated bacteria during plant growth in contaminated soils is unclear. The purpose of this study was to determine if plants had the ability to selectively enhance the prevalence of endophytes containing pollutant catabolic genes in unrelated environments contaminated with different pollutants. At petroleum hydrocarbon contaminated sites, two genes encoding hydrocarbon degradation, alkane monooxygenase (alkB) and naphthalene dioxygenase (ndoB), were two and four times more prevalent in bacteria extracted from the root interior (endophytic) than from the bulk soil and sediment, respectively. In field sites contaminated with nitroaromatics, two genes encoding nitrotoluene degradation, 2-nitrotoluene reductase (ntdAa) and nitrotoluene monooxygenase (ntnM), were 7 to 14 times more prevalent in endophytic bacteria. The addition of petroleum to sediment doubled the prevalence of ndoB-positive endophytes in Scirpus pungens, indicating that the numbers of endophytes containing catabolic genotypes were dependent on the presence and concentration of contaminants. Similarly, the numbers of alkB- or ndoB-positive endophytes in Festuca arundinacea were correlated with the concentration of creosote in the soil but not with the numbers of alkB- or ndoB-positive bacteria in the bulk soil. Our results indicate that the enrichment of catabolic genotypes in the root interior is both plant and contaminant dependent. 相似文献
59.
Methods for comparison of biotic regionalizations: the case of pteridophytes in the Iberian Peninsula 总被引:2,自引:0,他引:2
We made several regionalizations of the Iberian Peninsula based on the distributions of the pteridophyte flora to see whether the regionalization depended on the type and scale of lattice or the similarity index considered. We used five types of lattice in which the scale also varied: river basins, mountains and plains, natural regions, physiographic and geological regions, and administrative provinces; and two similarity indices: those of Jaccard and of Baroni-Urbani and Buser. The regionalizations varied according to the type of lattice, the grain size, and the similarity index used. To assess the different regionalizations we used four methods: 1) the coefficient of variation of the size of sites in each lattice. 2) the bestblock method, which considers as the hest lattice that which maximizes the number of matches between presences over all pairwise site comparisons. 3) the Mantel test, to assess the statistical significance of the regionalizations obtained, and 4) mapability, which considers the most contiguous regionalization to be the best. The best regionalization according to our four criteria was that based on administrative provinces and Jaccard's index. This yielded a small central region and three large regions: northern, western, and eastern. 相似文献
60.
S Barni P Lissoni D Mandelli C Archili G Real A L Sormani R Caprotti G Tancini 《The International journal of biological markers》1991,6(2):103-106
It has been suggested that both the menstrual cycle phase and postoperative changes in prolactin (PRL) secretion at the time of surgery may influence the prognosis of breast cancer. The present study was carried out to evaluate the relation between menstrual cycle period and surgery-induced PRL variations. We evaluated 32 premenopausal women with operable breast carcinoma; 17 were in perimenstrual phase (days 1-6 and 21-28) and 15 were in the mid-cycle (days 7-20) period at the time of surgery. To investigate serum levels of PRL, venous blood samples were collected before and 7 days after surgery. Postoperative hyperprolactinemia occurred in 17/32 patients and it was statistically more frequent in patients surgically treated during the perimenstrual phase than in the mid-cycle phase (12/17 vs 5/15; p less than 0.05), while no other parameter (including axillary node and estrogen receptor status) showed a significant influence on hyperprolactinemia rate. The results suggest that in premenopausal breast cancer patients surgery-induced hyperprolactinemia may be influenced by the menstrual cycle phase at the time of surgery. 相似文献