全文获取类型
收费全文 | 346篇 |
免费 | 10篇 |
出版年
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2017年 | 2篇 |
2016年 | 10篇 |
2015年 | 12篇 |
2014年 | 11篇 |
2013年 | 24篇 |
2012年 | 24篇 |
2011年 | 25篇 |
2010年 | 19篇 |
2009年 | 15篇 |
2008年 | 26篇 |
2007年 | 27篇 |
2006年 | 26篇 |
2005年 | 18篇 |
2004年 | 22篇 |
2003年 | 21篇 |
2002年 | 24篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有356条查询结果,搜索用时 15 毫秒
131.
132.
133.
Bozena Kolano Dorota Siwinska Luz Gomez Pando Joanna Szymanowska-Pulka Jolanta Maluszynska 《Plant Systematics and Evolution》2012,298(1):251-255
The extent and significance of intraspecific genome size variation were analysed in quinoa (Chenopodium quinoa Willd.), a pseudocereal important for human consumption in the Andean region of South America. Flow cytometry, with propidium
iodide as the DNA stain, was used to estimate the genome size of 20 quinoa accessions from Ecuador, Peru, Bolivia, Argentina,
Chile and the USA. Limited genome size variation was found among the analysed accessions. The differences between the accessions
were statistically significant but the maximum inter-accession difference between the populations with the largest and the
smallest genome reached only 5.9%. The largest genome was found in population C4 from Chile (mean 3.077 pg/2C) and the smallest
in the Peruvian population P2 (mean 2.905 pg/2C). The variation was not correlated with collection site; however, the quinoa
accessions analysed in this study belonged to three distinct geographical groups: northern highland, southern highland and
lowland. 相似文献
134.
Galpin AJ Raue U Jemiolo B Trappe TA Harber MP Minchev K Trappe S 《Analytical biochemistry》2012,425(2):175-182
The aim of this project was to develop a method to assess fiber type specific protein content across the continuum of human skeletal muscle fibers. Individual vastus lateralis muscle fibers (n = 264) were clipped into two portions: one for sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) fiber typing and one for Western blot protein identification. Following fiber type determination, fiber segments were combined into fiber type specific pools (~20 fibers/pool) and measured for total protein quantity, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), citrate synthase (CS), and total p38 content. GAPDH content was 64, 54, 160, and 138% more abundant in myosin heavy chain (MHC) I/IIa, MHC IIa, MHC IIa/IIx, and MHC IIx fibers, respectively, when compared with MHC I. Inversely, CS content was 528, 472, 242, and 47% more abundant in MHC I, MHC I/IIa, MHC IIa, and MHC IIa/IIx fibers, respectively, when compared with MHC IIx. Total p38 content was 87% greater in MHC IIa versus MHC I fibers. These data and this approach establish a reliable method for human skeletal muscle fiber type specific protein analysis. Initial results show that particular proteins exist in a hierarchal fashion throughout the continuum of human skeletal muscle fiber types, further highlighting the necessity of fiber type specific analysis. 相似文献
135.
Niederer L Kuhnert P Egger R Büttner S Hächler H Korczak BM 《Applied and environmental microbiology》2012,78(1):288-291
Multilocus sequence typing (MLST) extended with flaB typing of 425 Campylobacter jejuni isolates and 42 Campylobacter coli isolates revealed quite a low overlap between human isolates from travel-associated and domestic cases in Switzerland. Men were more frequently affected by Campylobacter than women, but strains from women and, overall, from travel-associated cases showed mutations conferring quinolone resistance more frequently than strains from men and domestic cases, respectively. 相似文献
136.
Schorderet DF Nichini O Boisset G Polok B Tiab L Mayeur H Raji B de la Houssaye G Abitbol MM Munier FL 《American journal of human genetics》2008,82(5):1178-1184
Several dysmorphic syndromes affect the development of both the eye and the ear, but only a few are restricted to the eye and the external ear. We describe a developmental defect affecting the eye and the external ear in three members of a consanguineous family. This syndrome is characterized by ophthalmic anomalies (microcornea, microphthalmia, anterior-segment dysgenesis, cataract, coloboma of various parts of the eye, abnormalities of the retinal pigment epithelium, and rod-cone dystrophy) and a particular cleft ear lobule. Linkage analysis and mutation screening revealed in the first exon of the NKX5-3 gene a homozygous 26 nucleotide deletion, generating a truncating protein that lacked the complete homeodomain. Morpholino knockdown expression of the zebrafish nkx5-3 induced microphthalmia and disorganization of the developing retina, thus confirming that this gene represents an additional member implicated in axial patterning of the retina. 相似文献
137.
Neuroprotectant FK506 inhibits glutamate-induced apoptosis of astrocytes in vitro and in vivo 总被引:4,自引:0,他引:4
Neuron-astrocyte interactions are critical for signalling, energy metabolism, extracellular ion and glutamate homeostasis, volume regulation and neuroprotection in the CNS. Glutamate uptake by astrocytes may prevent excitotoxic glutamate elevation and determine neuronal survival. However, an excess of glutamate can cause the death of astrocytes. FK506, an inhibitor of calcineurin, and an immunosuppressive drug, is neuroprotective in animal models of neurologic diseases, including focal and global ischaemia. In the present work, we demonstrate that a single injection of FK506 60 min after a transient middle cerebral artery occlusion (MCAo) significantly decreases the number of terminal deoxynucleotidyl transferase nick-end labelling (TUNEL)-positive cells in the ischaemic cortex and striatum. Using 3-D confocal microscopy we found that, 24 h after MCAo, many TUNEL-positive cells in the ischaemic striatum and cortex are astrocytes. Furthermore, we demonstrate that exposure of cultured cortical astrocytes to 50-100 mM Glu for 24 h induces apoptotic alterations in nuclear morphology, DNA fragmentation, dissipation of mitochondrial transmembrane potential (DeltaPsi) and caspase activation. FK506 (1 muM) efficiently inhibits Glu-induced apoptosis of cultured astrocytes, DNA fragmentation and changes in mitochondrial DeltaPsi. Our findings suggest that modulation of glutamate-induced astrocyte death early after reperfusion may be a novel mechanism of FK506-mediated neuroprotection in ischaemia. 相似文献
138.
Abnormal shoot branching was observed in Pinus sylvestris trees in Poland. These abnormalities resulted in the formation of dense, ball‐like structures with dwarfed needles. The presence of phytoplasma in the needles of branched and surrounding symptomless shoots was demonstrated using nested‐polymerase chain reaction (PCR) with universal primer pairs that amplified phytoplasma 16S rDNA, as well as using restriction fragment length polymorphic analysis of PCR products. Comparison of nucleotide sequences of DNA samples from three P. sylvestris trees with ball‐like structures revealed that their fragments of 16S rDNA were identical. The nucleotide sequence showed more than 99% similarity with the corresponding fragments of sequence of ‘Candidatus phytoplasma pini’. 相似文献
139.
Katarzyna H Kaminska Mikihiko Kawai Michal Boniecki Ichizo Kobayashi Janusz M Bujnicki 《BMC structural biology》2008,8(1):48
Background
Catalytic domains of Type II restriction endonucleases (REases) belong to a few unrelated three-dimensional folds. While the PD-(D/E)XK fold is most common among these enzymes, crystal structures have been also determined for single representatives of two other folds: PLD (R.BfiI) and half-pipe (R.PabI). Bioinformatics analyses supported by mutagenesis experiments suggested that some REases belong to the HNH fold (e.g. R.KpnI), and that a small group represented by R.Eco29kI belongs to the GIY-YIG fold. However, for a large fraction of REases with known sequences, the three-dimensional fold and the architecture of the active site remain unknown, mostly due to extreme sequence divergence that hampers detection of homology to enzymes with known folds. 相似文献140.