全文获取类型
收费全文 | 197篇 |
免费 | 31篇 |
出版年
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 8篇 |
2012年 | 12篇 |
2011年 | 12篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 7篇 |
2007年 | 10篇 |
2006年 | 13篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 5篇 |
1999年 | 6篇 |
1998年 | 9篇 |
1997年 | 2篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 9篇 |
1990年 | 2篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1965年 | 2篇 |
1959年 | 1篇 |
1956年 | 1篇 |
1951年 | 1篇 |
1925年 | 1篇 |
1924年 | 2篇 |
1923年 | 1篇 |
排序方式: 共有228条查询结果,搜索用时 15 毫秒
111.
112.
NELL1 and NELL2 (neural epidermal growth factor-like 1 and 2) are recently described members of the epidermal growth factor gene family that have previously been shown to be expressed almost exclusively in brain tissue. Here we demonstrate regulated expression of NELL1 and NELL2 in human hematopoietic cells. Mature NELL1 mRNA is not detected in any normal hemopoietic cell type, although the gene is transcribed during a narrow window of pre-B cell development, and cell lines at the same developmental stage express the NELL1 mRNA. The related NELL2 gene is expressed by all nucleated peripheral blood cells examined (B, T, monocyte, and natural killer cells), but not in any of the bone marrow B lineage cells at earlier stages of development. However, leukemic cell lines corresponding to the same early differentiation stages express abundant NELL2 mRNA. These results suggest normal and possible oncogenic roles for the NELL proteins in hemopoietic cells. 相似文献
113.
114.
Adoption programs can be enormously satisfying for all involved-not least the animals themselves-and constitute an important refinement in humane animal care and use. Most of the potential problems associated with adoption can be minimized with careful thought and planning. The authors describe adoption programs at two large academic campuses, noting differences between direct and indirect programs. 相似文献
115.
A new magnetic resonance imaging (MRI) contrast agent designed to mimic sialyl Lewis X (sLeX) and to target inflammation has been synthesized and characterized. The evolution of its proton longitudinal relaxivity as a function of the magnetic field (NMRD) and temperature has been studied. The exchange rate of the water coordinated to the metal has been assessed by oxygen-17 relaxometry. The transmetalation by zinc(II) ions and the noncovalent binding to human serum albumin have been evaluated. The results show no limitation by the residence time of the coordinated water molecule above room temperature, a higher stability of the complex versus transmetalation by zinc(II) ions than a parent complex, the clinically used Gd-DTPA-BMA, and negligible interaction with human serum albumin. 相似文献
116.
Gautam?Aggarwal EA?Worthey Paul?D?McDonagh Peter?J?MylerEmail author 《BMC bioinformatics》2003,4(1):23
Background
Seattle Biomedical Research Institute (SBRI) as part of the Leishmania Genome Network (LGN) is sequencing chromosomes of the trypanosomatid protozoan species Leishmania major. At SBRI, chromosomal sequence is annotated using a combination of trained and untrained non-consensus gene-prediction algorithms with ARTEMIS, an annotation platform with rich and user-friendly interfaces.Results
Here we describe a methodology used to import results from three different protein-coding gene-prediction algorithms (GLIMMER, TESTCODE and GENESCAN) into the ARTEMIS sequence viewer and annotation tool. Comparison of these methods, along with the CODON USAGE algorithm built into ARTEMIS, shows the importance of combining methods to more accurately annotate the L. major genomic sequence.Conclusion
An improvised and powerful tool for gene prediction has been developed by importing data from widely-used algorithms into an existing annotation platform. This approach is especially fruitful in the Leishmania genome project where there is large proportion of novel genes requiring manual annotation.117.
118.
Angelo Peccerillo Giuliano F. Panza Abdelkrim Aoudia Maria Luce Frezzotti 《Rendiconti Lincei》2008,19(4):291-309
Shear-wave (V
S
) tomography along transects across the Western-Central Mediterranean area reveals heterogeneous lateral and vertical physical
characteristics in the lithosphere-asthenosphere system (LAS). A 50 km thick low velocity layer (LVL), with V
S
∼ 4.0–4.2 km/sec, typical of low rigidity fluid-bearing mantle material, is observed at a depth of about 70–120 km from offshore
Provence, to Sardinia and the Central Tyrrhenian Sea. This LVL, enclosed between higher velocity mantle rocks, rises to a
depth of less than 30 km below the recent and active volcanoes of Central Italy and the Southern Tyrrhenian Sea, where a maximum
in the heath flow is observed. The LVL is absent beneath Southeastern France and the northern border of the African foreland.
In the Balearic Sea-Sardinia-Central Tyrrhenian section, the depth of LVL corresponds to pressure conditions of minimum temperature
of peridotite+CO2+H2O solidus, consistent with conditions where fluid loss from the slab and mantle flow over the subducting plate favor significant
melt generation above steep, west-dipping subduction zones. It is suggested that LVL in the Balearic-Tyrrhenian domains is
the result of mantle contamination and melting left behind by the eastward retreating Adriatic-Ionian subducting plates from
Oligo-Miocene to present. This layer also marks a discontinuity between the lithospere and underlying mantle behind the subduction
zone, favoring detachment and westward drift of the lithosphere, and consequent opening of backarc basins.
These data support the hypothesis that the orogenic Oligocene to Quaternary volcanism in the Western Mediterranean area is
the effect of shallow mantle processes, and argue against the presence of deep mantle plumes. A shallow-mantle origin is also
suggested for the EM1-type Plio-Quaternary anorogenic magmatism in Sardinia and for the FOZO-DMM-type magmatism on the northern
margin of the African foreland.
相似文献
119.
Benziwa Nathalie Johnson Marie Luce Akossiwoa Quashie Gilles Chaix Letizia CamusKulandaivelu Kossi Adjonou Kossi Novinyo Segla Adzo Dzifa Kokutse Christine Ouinsavi Babou Andr Bationo Habou Rabiou Kouami Kokou Hlne Vignes 《Ecology and evolution》2020,10(23):13403
To study the genetic diversity and structure of the forest species Pterocarpus erinaceus Poir., seventeen polymorphic nuclear microsatellite markers were isolated and characterized, using next‐generation sequencing. Three hundred and sixty‐five (365) individuals were analyzed within fifteen (15) West African populations. The number of alleles for these loci varied from 4 to 30, and the heterozygosity varied from 0.23 to 0.82. The seventeen (17) primers designed here will allow characterizing the genetic diversity of this threaten species on its natural stands and to better understand the population differentiation mechanisms shaping it. 相似文献
120.