全文获取类型
收费全文 | 284篇 |
免费 | 22篇 |
国内免费 | 5篇 |
出版年
2021年 | 4篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 13篇 |
2015年 | 10篇 |
2014年 | 20篇 |
2013年 | 24篇 |
2012年 | 20篇 |
2011年 | 24篇 |
2010年 | 11篇 |
2009年 | 14篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 10篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 11篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1964年 | 1篇 |
1962年 | 1篇 |
1938年 | 1篇 |
排序方式: 共有311条查询结果,搜索用时 31 毫秒
61.
A modified Segmental Sedimentation and Counting Technique (SSCT) to examine the presence of Echinococcus multilocularis helminths in segments of fox (Vulpes vulpes) intestine is described and compared to the “gold standard”, SCT. Out of the 358 intestines collected, 117 were E. multilocularis positive. Using SSCT methods we compare the sensitivity of individual or pairs of segments to establish a tradeoff between saving time and the reliability of the diagnosis, especially in areas with low infection intensities. The results show that the analysis of segment S4 associated with segment S1 or S2 give 98.3% sensitivity, with specificity close to 100%. Based on our results and the time saved, we recommend using SSCT for routine examination of fox intestines for large epidemiological studies, particularly where the endemic prevalence of E. multilocularis is low or unknown. 相似文献
62.
We cloned the cDNA and genomic DNA encoding for Izumo1 of cashmere goat (Capra hircus) and sheep (Ovis aries). Analysis of 4.6 kb Izumo1 genomic sequences in sheep and goat revealed a canonical open reading frame (ORF) of 963 bp spliced
by eight exons. Sheep and goat Izumo1 genes share >99% identity at both DNA and protein levels and are also highly homologous to the orthologues in cattle, mouse,
rat and human. Extensive cloning and analysis of Izumo1 cDNA revealed three (del 69, del 182 and del 217) and two (del 69
and ins 30) alternative splicing isoforms in goat and sheep, respectively. All of the isoforms are derived from splicing at
typical GT-AG sites leading to partial or complete truncation of the immunoglobulin (Ig)-like domain. Bioinformatics analysis
showed that caprine and ovine Izumo1 proteins share similar structure with their murine orthologue. There are a signal peptide
at the N-terminus (1–22 aa), a transmembrane domain at the C-terminus (302–319 aa), and an extracellular Ig-like region in
the middle (161–252 aa) with a putative N-linked glycosylation site (N205-N-S). Alignment of Izumo1 protein sequences among 15 mammalian species displayed several highly conserved regions, including
LDC and YRC motifs with cysteine residues for potential disulfide bridge formation, CPNKCG motif upstream of the Ig-like domain,
GLTDYSFYRVW motif upstream of the putative N-linked glycosylation site, and a number of scattered cysteine residues. These
distinctive features are very informative to pinpoint the important gene motifs and functions. The C-terminal regions, however,
are more variable across species. Izumo1 cDNA sequences of goat, sheep, and cow were found to be largely homologous, and the
molecular phylogenetic analysis is consistent with their morphological taxonomy. This implies the Izumo1 gene evolves from the same ancestor, and the mechanism of sperm–egg fusion in mammals may be under the same principle in
which Izumo1 plays an important role. 相似文献
63.
小肠上皮细胞作为肠道的主要功能细胞,在多种肠道疾病和上皮间质转化的研究中发挥着重要的作用。采取组织块消化和肠绒毛消化两种方法对新生仔猪小肠上皮细胞进行分离培养,传代后通过细胞形态学及免疫荧光等方法对其进行鉴定,结果表明:肠绒毛消化法所获得的小肠上皮细胞要远好于组织块消化法所得细胞,细胞在24~48h贴壁,呈现出典型的三角形或多角形样,10~12d细胞汇合成片、单层生长、互不重叠;细胞角蛋白18(cytokeratin-18)和尾型同源盒基因2(Cdx2)阳性,碱性磷酸酶检测阴性,扫描电镜下可以清楚地看到均匀分布的肠绒毛。以上结果表明,该实验成功建立出可连续传代并符合小肠上皮细胞鉴定标准的仔猪小肠上皮细胞。 相似文献
64.
Farah Abdel Samad Alex Baumel Marianick Juin Daniel Pavon Sonia Siljak-Yakovlev Frédéric Médail Magda Bou Dagher Kharrat 《Plant Systematics and Evolution》2014,300(5):819-830
The Lebanese mountain range is an important zone of plant species richness and endemism where the genus Astragalus constitutes a principal component of plant biodiversity. Most of endemic Astragalus taxa, living in mountains and arid zones of Mounts Lebanon and anti-Lebanon, are characterized by a cushion, spiny vegetative form, named “tragacanthic”, which is a remarkable example of vegetative convergence evolution. Because of determination difficulties, taxonomic uncertainties, and discrepancy in the number of taxa listed according to authors, new data are hardly needed to improve systematics of Astragalus and to investigate the role of the Lebanese mountain range as refugia of biodiversity. Before this study only two values on the genome size of Astragalus were reported in the literature and no previous molecular studies had been carried out on Astragalus genus in Lebanon. We examined the utility of rDNA ITS molecular markers to distinguish Astragalus species of Lebanese mountain range and the variation range of their genome size. The main results revealed a striking diversity in Lebanese Astragalus species with the emphasis of a huge variation of genome sizes, an important inter-specific chromosome polymorphism and the existence of a high phylogenetic diversity. The strict endemic species of the Lebanese mountains are positioned throughout the phylogeny. These results confirm that the Lebanon and anti-Lebanon mounts constitute a third diversity center for Astragalus and that high altitude areas are important refugia of plant biodiversity despite centuries of exploitation by humans. 相似文献
65.
66.
67.
Kabindra Adhikari Alfred E. Hartemink Budiman Minasny Rania Bou Kheir Mette B. Greve Mogens H. Greve 《PloS one》2014,9(8)
Estimation of carbon contents and stocks are important for carbon sequestration, greenhouse gas emissions and national carbon balance inventories. For Denmark, we modeled the vertical distribution of soil organic carbon (SOC) and bulk density, and mapped its spatial distribution at five standard soil depth intervals (0−5, 5−15, 15−30, 30−60 and 60−100 cm) using 18 environmental variables as predictors. SOC distribution was influenced by precipitation, land use, soil type, wetland, elevation, wetness index, and multi-resolution index of valley bottom flatness. The highest average SOC content of 20 g kg−1 was reported for 0−5 cm soil, whereas there was on average 2.2 g SOC kg−1 at 60−100 cm depth. For SOC and bulk density prediction precision decreased with soil depth, and a standard error of 2.8 g kg−1 was found at 60−100 cm soil depth. Average SOC stock for 0−30 cm was 72 t ha−1 and in the top 1 m there was 120 t SOC ha−1. In total, the soils stored approximately 570 Tg C within the top 1 m. The soils under agriculture had the highest amount of carbon (444 Tg) followed by forest and semi-natural vegetation that contributed 11% of the total SOC stock. More than 60% of the total SOC stock was present in Podzols and Luvisols. Compared to previous estimates, our approach is more reliable as we adopted a robust quantification technique and mapped the spatial distribution of SOC stock and prediction uncertainty. The estimation was validated using common statistical indices and the data and high-resolution maps could be used for future soil carbon assessment and inventories. 相似文献
68.
Patrice?Njomnang?Soh Boris?Delaunay Elie?Bou?Nasr Martine?Delannes Michel?Soulie Eric?HuygheEmail author 《Andrologie》2014,24(1):13
Purpose
To assess sexual functions and behaviors of men treated by penile brachytherapy for a cancer of the penis.Materials and methods
Thirty eight men (19 patients treated by penile brachytherapy for a cancer of the penis and 19 age paired-matched controls) participated in a survey about sexuality. The mean age of patients and controls were 73.2 +/- 11.7 and 70.0 +/- 10.5 years, respectively (NS). Controls were men without penile pathology, without history of cancer and no evidence of cognitive impairment. All agreed to participate in the survey about sexuality using 2 questionnaires : the IIEF questionnaire, which explores 4 domains of sexual functions, namely erection, satisfaction, orgasm and desire, and a questionnaire created using the BASIC IDEA grid, which addresses nine domains: behavior, affect, sensation, self-image, cognition, interpersonal, drugs, expectation and attitude.Results
Patients had better scores than controls in 3 domains of the IIEF: erection, desire and satisfaction. These results contrasted with the frequency of intercourse and the quality of erection (evaluated through the BASIC IDEA questionnaire) that were not significantly different between the two populations. Patients also had significantly higher frequency of masturbation (p <0.001) lower worry about sexual performance and higher expected satisfaction for future life (p: 0.021) than controls.Conclusion
Penile brachytherapy is a treatment of cancer of the penis that seems to have a moderated impact on sexual functions since most of sexual scores are not inferior in these patients than in age pair-matched controls.69.
70.
Petra Matou?ková Hana Bártíková Iva Bou?ová Veronika Hanu?ová Barbora Szotáková Lenka Skálová 《PloS one》2014,9(1)
Obesity and metabolic syndrome is increasing health problem worldwide. Among other ways, nutritional intervention using phytochemicals is important method for treatment and prevention of this disease. Recent studies have shown that certain phytochemicals could alter the expression of specific genes and microRNAs (miRNAs) that play a fundamental role in the pathogenesis of obesity. For study of the obesity and its treatment, monosodium glutamate (MSG)-injected mice with developed central obesity, insulin resistance and liver lipid accumulation are frequently used animal models. To understand the mechanism of phytochemicals action in obese animals, the study of selected genes expression together with miRNA quantification is extremely important. For this purpose, real-time quantitative PCR is a sensitive and reproducible method, but it depends on proper normalization entirely. The aim of present study was to identify the appropriate reference genes for mRNA and miRNA quantification in MSG mice treated with green tea catechins, potential anti-obesity phytochemicals. Two sets of reference genes were tested: first set contained seven commonly used genes for normalization of messenger RNA, the second set of candidate reference genes included ten small RNAs for normalization of miRNA. The expression stability of these reference genes were tested upon treatment of mice with catechins using geNorm, NormFinder and BestKeeper algorithms. Selected normalizers for mRNA quantification were tested and validated on expression of NAD(P)H:quinone oxidoreductase, biotransformation enzyme known to be modified by catechins. The effect of selected normalizers for miRNA quantification was tested on two obesity- and diabetes- related miRNAs, miR-221 and miR-29b, respectively. Finally, the combinations of B2M/18S/HPRT1 and miR-16/sno234 were validated as optimal reference genes for mRNA and miRNA quantification in liver and 18S/RPlP0/HPRT1 and sno234/miR-186 in small intestine of MSG mice. These reference genes will be used for mRNA and miRNA normalization in further study of green tea catechins action in obese mice. 相似文献