全文获取类型
收费全文 | 207篇 |
免费 | 14篇 |
出版年
2023年 | 2篇 |
2020年 | 2篇 |
2018年 | 3篇 |
2016年 | 4篇 |
2015年 | 13篇 |
2014年 | 7篇 |
2013年 | 15篇 |
2012年 | 17篇 |
2011年 | 12篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 14篇 |
2007年 | 3篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 13篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1964年 | 2篇 |
1963年 | 1篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1959年 | 1篇 |
1939年 | 1篇 |
1938年 | 2篇 |
1932年 | 1篇 |
1929年 | 1篇 |
1928年 | 2篇 |
1927年 | 1篇 |
排序方式: 共有221条查询结果,搜索用时 15 毫秒
61.
Po-Chun Chen Jen-Leih Wu Guor Mour Her Jiann-Ruey Hong 《Fish & shellfish immunology》2010,28(2):344-353
Aquatic birnavirus induces necrotic cell death by an ill-understood process. Presently, we demonstrate that infectious pancreatic necrosis virus (IPNV) induces post-apoptotic necrotic cell death through loss of mitochondrial membrane potential (MMP) followed by caspase-3 activation in CHSE-214 cells. Progressive phosphatidylserine externalization was observed at 6 h post-infection (p.i.). This was followed by the development of bulb-like vesicles (bleb formation) at 8 h p.i. Progressive loss of MMP was also observed in IPNV-infected CHSE-214 cells beginning at 6 h p.i. At 8 h and 12 h p.i., IPNV-infected cells demonstrated a dramatic increase in MMP loss, rapid entry into necrotic cell death, and activation of caspase-9 and -3. Additionally, treatment with an inhibitor of MMP loss, bongkrekic acid, an adenine nucleotide translocase inhibitor, blocked IPNV-induced PS exposure and MMP loss, as well as reduced the activation of caspase-3. Taken together, our results suggest that IPNV induces apoptotic cell death via loss of MMP, thereby triggering secondary necrosis and caspases-3 activation. Furthermore, this death-signaling pathway is disrupted by bongkrekic acid in fish cells, indicating that this drug may serve to modulate IPNV-induced pathogenesis. 相似文献
62.
Jae-Hyuk Her Peter W. Stephens Bretni S. Kennon Joel S. Miller 《Inorganica chimica acta》2010,364(1):172-175
Reaction of [Ru2(O2CMe)4]Cl and K2[Ni(CN)4] forms [Ru2(O2CMe)4]2[Ni(CN)4] with the targeted layered structure possessing Ru-NCNi linkages, albeit strained, with Ru-NC and Ni-CN angles in the range of 147-167°. The magnetic properties of [Ru2(O2CMe)4]2[Ni(CN)4] can be fit to a zero-field splitting model with D/kB = 95 K (66 cm−1). 相似文献
63.
64.
Nordihydroguaiaretic acid, an antioxidant, inhibits transforming growth factor-beta activity through the inhibition of Smad signaling pathway 总被引:1,自引:0,他引:1
Transforming growth factor-beta (TGF-beta) and its family are potent and multi-functional cytokines that affect various fundamental biological events. TGF-beta has a unique signaling pathway that is carried by Smad family, and many recent studies showed the extensive crosstalk between Smad pathway and other signaling pathway. There were also clear evidences for the involvement of oxidative events in TGF-beta signaling pathway. To elucidate the role of oxidative events in carrying TGF-beta signals, we examined the effect of various antioxidants on TGF-beta activities in osteoblastic cell line. Among the examined compounds, we found nordihydroguaiaretic acid (NDGA) has a unique and strong inhibitory effect on various TGF-beta activities. Since the majority of TGF-beta activities are mediated by Smad, we questioned whether NDGA blocks the Smad signaling pathway. The result showed that NDGA inhibits the translocation of Smad2 to the nucleus. Further study revealed the strong inhibitory effect of NDGA on the phosphorylation of Smad2. This result may be important for designing chemical modulators of TGF-beta and its family related events and may provide new insights into the action mechanism of antioxidant. 相似文献
65.
In an endeavor to contribute to the comprehension of the evolution of transposable elements (TEs) in the genome of host species, we investigated the phylogenetic relationships of sequences homologous to the retrotransposon gypsy of Drosophila melanogaster in 19 species of Drosophila, in Scaptodrosophila latifasciaeformis, and in Zaprionus indianus. This phylogenetic study was based on approximately 500 base pairs of the env gene. Our analyses showed considerable discrepancy between the phylogeny of gypsy elements and the relationship of their host species, and they allow us to infer a complex evolutionary pattern that could include ancestral polymorphism, vertical transmission, and several cases of horizontal transmission. 相似文献
66.
Nightingale KK Schukken YH Nightingale CR Fortes ED Ho AJ Her Z Grohn YT McDonough PL Wiedmann M 《Applied and environmental microbiology》2004,70(8):4458-4467
A case-control study involving 24 case farms with at least one recent case of listeriosis and 28 matched control farms with no listeriosis cases was conducted to probe the transmission and ecology of Listeria monocytogenes on farms. A total of 528 fecal, 516 feed, and 1,012 environmental soil and water samples were cultured for L. monocytogenes. While the overall prevalence of L. monocytogenes in cattle case farms (24.4%) was similar to that in control farms (20.2%), small-ruminant (goat and sheep) farms showed a significantly (P < 0.0001) higher prevalence in case farms (32.9%) than in control farms (5.9%). EcoRI ribotyping of clinical (n = 17) and farm (n = 414) isolates differentiated 51 ribotypes. L. monocytogenes ribotypes isolated from clinical cases and fecal samples were more frequent in environmental than in feed samples, indicating that infected animals may contribute to L. monocytogenes dispersal into the farm environment. Ribotype DUP-1038B was significantly (P < 0.05) associated with fecal samples compared with farm environment and animal feedstuff samples. Ribotype DUP-1045A was significantly (P < 0.05) associated with soil compared to feces and with control farms compared to case farms. Our data indicate that (i) the epidemiology and transmission of L. monocytogenes differ between small-ruminant and cattle farms; (ii) cattle contribute to amplification and dispersal of L. monocytogenes into the farm environment, (iii) the bovine farm ecosystem maintains a high prevalence of L. monocytogenes, including subtypes linked to human listeriosis cases and outbreaks, and (iv) L. monocytogenes subtypes may differ in their abilities to infect animals and to survive in farm environments. 相似文献
67.
Abnormal neurofilament transport caused by targeted disruption of neuronal kinesin heavy chain KIF5A
Xia CH Roberts EA Her LS Liu X Williams DS Cleveland DW Goldstein LS 《The Journal of cell biology》2003,161(1):55-66
To test the hypothesis that fast anterograde molecular motor proteins power the slow axonal transport of neurofilaments (NFs), we used homologous recombination to generate mice lacking the neuronal-specific conventional kinesin heavy chain, KIF5A. Because null KIF5A mutants die immediately after birth, a synapsin-promoted Cre-recombinase transgene was used to direct inactivation of KIF5A in neurons postnatally. Three fourths of such mutant mice exhibited seizures and death at around 3 wk of age; the remaining animals survived to 3 mo or longer. In young mutant animals, fast axonal transport appeared to be intact, but NF-H, as well as NF-M and NF-L, accumulated in the cell bodies of peripheral sensory neurons accompanied by a reduction in sensory axon caliber. Older animals also developed age-dependent sensory neuron degeneration, an accumulation of NF subunits in cell bodies and a reduction in axons, loss of large caliber axons, and hind limb paralysis. These data support the hypothesis that a conventional kinesin plays a role in the microtubule-dependent slow axonal transport of at least one cargo, the NF proteins. 相似文献
68.
69.
Structural studies of a novel exopolysaccharide produced by a mutant of Rhizobium meliloti strain Rm1021 总被引:4,自引:0,他引:4
The structure of a novel expolysaccharide obtained from a mutant of Rhizobium meliloti strain Rm1021 was elucidated by a combination of enzymic, chemical, and spectroscopic methods. The polysaccharide is composed of a disaccharide repeating-unit, beta-D-Glcp-(1----3)-alpha-D-Galp-(1----3), having a 6-O-acetyl group attached to most D-glucose residues and a 4,6-O-(1-carboxyethylidene) group attached to every D-galactose residue. 相似文献
70.
Huang CK Chang BS Wang KC Her SJ Chen TW Chen YA Cho CL Liao LJ Huang KL Chen WS Liu ZH 《Journal of plant physiology》2004,161(6):709-713
In the day-neutral plant Polianthes tuberosa (cv. Double) putrescine and spermine in corms at the early floral initiation stage decreased by 26 and 36%, respectively, compared with that in the vegetative stage. In contrast, a sharp increase in spermidine and cadaverine titers in corms was recorded at the early floral initiation stage. However, cadaverine in corms disappeared at the flower development stage. Polyamines in the roots were generally lower than those in the leaves and corms. In no case was the change in endogenous polyamine titers in the roots and leaves associated with floral initiation and flower development in P. tuberosa. Exogenous application of spermidine at 5, 25 or 150 microg per plant at the vegetative stage did not affect flower primordium counts. However, addition of a spermidine synthase inhibitor, cyclohexylamine, at 150 or 250 microg per plant (each dose was applied two times in total at an interval of 4 days) significantly reduced flower primordium counts, indicating that spermidine is involved in floral initiation and floral development in P. tuberosa. In P. tuberosa corms at the vegetative stage arginine decarboxylase activity rises and decreases at the early floral initiation stage. In contrast, ornithine decarboxylase activity reaches the highest level at the early floral initiation stage and declines significantly at the vegetative stage. Results indicate that an increase in spermidine and a transient increase in cadaverine titers in the corms seem characteristic of early floral initiation in P. tuberosa. It is also suggested that a significant reduction in putrescine and spermine in the corms is involved in the early floral initiation in P. tuberosa. 相似文献