全文获取类型
收费全文 | 85篇 |
免费 | 6篇 |
出版年
2021年 | 3篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 6篇 |
2012年 | 4篇 |
2011年 | 4篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1973年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有91条查询结果,搜索用时 15 毫秒
11.
Tree seasonality in a warming climate 总被引:1,自引:0,他引:1
Climate warming has increased researchers' interest in plant phenology and its modelling. Although the main focus is on projections of accelerated springtime phenological events, also a further extension of the growing season by delayed growth cessation is often projected. However, ecophysiological studies indicate that, for boreal and temperate trees, such generalisations are precluded owing to differential climatic conditions and inter- and intraspecific genetic differences. The annual cycle of these trees is an integrated system, where one phase affects subsequent phases, resulting in delayed impacts, which are only partially addressed in current ecophysiological models. Here, we outline an updated integrated conceptual model of the annual cycle by identifying ecophysiological phenomena that are particularly significant under climate warming. 相似文献
12.
Streptavidin derived from Streptomyces avidinii was displayed on the cell surface of the yeast Saccharomyces cerevisiae by cell-surface engineering using two types of plasmid for the expression of a native subunit and an anchored subunit fused with the C-terminus of 318 amino acids of Flo1p containing a glycosylphosphatidylinositol anchor attachment signal. The displayed streptavidin had the binding ability for biotinylated compounds. This was confirmed by fluorescence microscopy after the adsorption of yeast cells displaying streptavidin and biotinylated fluorescein isothiocyanate. On the other hand, streptavidin produced by cells harboring only the plasmid for the expression of the anchored subunit showed a very low binding activity for biotinylated compounds. Cells displaying streptavidin may constitute novel whole-cell affinity adsorbents widely used for immunoassay and biosensing. This coexpression method will ensure that proteins, such as homo- and hetero-oligomeric proteins, are displayed on the cell surface in an active form. 相似文献
13.
14.
Deficiency of inducible nitric oxide synthase exacerbates hepatic fibrosis in mice fed high-fat diet
Yi Chen Sadaaki Sawamura Naoto Fukuyama Tetsuya Mine Ryuzaburo Tanino Hiroe Nakazawa 《Biochemical and biophysical research communications》2004,326(1):45-51
The role of inducible nitric oxide synthase (iNOS) in the progression of fibrosis during nonalcoholic steatohepatitis remains to be elucidated. This study examined the role of iNOS in the progression of fibrosis during steatohepatitis by comparing iNOS knockout (iNOS−/−) and wild-type (iNOS+/+) mice that were fed a high-fat diet. Severe fatty metamorphosis developed in the liver of iNOS+/+ and iNOS−/− mice. Fibrotic changes were marked in iNOS−/− mice. Gelatin zymography showed that pro MMP-2 and pro MMP-9 protein expressions were more highly induced in iNOS+/+ mice than in iNOS−/− mice. Active forms of MMP-2 and MMP-9 were clearly present only in the liver tissue of iNOS+/+ mice. In situ zymography showed strong gelatinolytic activities in the liver tissue of iNOS+/+ mice, but only spotty activity in iNOS−/−mice. iNOS may attenuate the progression of liver fibrosis in steatohepatitis, in part by inducing MMP-2 and MMP-9 expression and augmenting their activity. 相似文献
15.
Kohji Egawa Naohiro Seo Takae Tanino Tomomi Tsukiyama 《Cancer immunology, immunotherapy : CII》1996,41(6):384-388
Q5 antigens are expressed on the surface of various experimental murine tumor cells. They share partially common antigenicity with Qa-2 alloantigens expressed on normal lymphocytes. For that reason we tested the immunoprotection by anti-Qa-2 immunization of mice against a Q5+ tumor. Nerve fibrosarcoma (NSFA) tumor, which specifically develops metastasis in the lung, has been reported to be poorly immunogenic. However, expression of the Q5 antigen was evident on the surface of NFSA cells. After immunizing (C3H/He x B6.K1)F1 (Qa-2-) mice with B6 (Qa-2+) lymphocytes, the protection against the proliferation of the semi-syngeneic NFSA tumor was examined First, immunization of normal mice induced resistance to NFSA cell transplants. Second, when the tumor cells were transplanted to the hind foot of a mouse and the resulting tumor was removed by amputating the leg, the mice were protected against the development of lung metastasis after immunization by intraperitoneal inoculation of B6 cells 3 days after tumor removal. Immunization with attenuated NFSA cells in this system failed to protect the mice from lung metastasis. On the other hand, inoculation of the mice with B6 cells without removal of the original tumor on the foot showed little effect on the progression of the tumor. Thus, cytotoxic T lymphocytes (CTL), which seemed to be present in an inactive form in the mice from which the tumor had not been removed, were induced in the mice after the removal of the major tumor followed by immunization with B6 lymphocytes. The induction of CTL by the immunization was suppressed in mice bearing large tumors. Cells stimulated by the tumor antigen seemed to be involved in the suppression. It was also shown that the Q5 antigen is the direct recognition target of the CTL since the activity of Q5-specific CTL clones in lysing tumor cells was inhibited by a monoclonal antibody specific for the Q5 antigen. In contrast to immunization with attenuated tumor cells, our novel allogeneic lymphocyte immunization procedure offers high CTL activation, by-passing the induction of T cell unresponsiveness. 相似文献
16.
Melanoma is the most lethal cutaneous cancer with a highly aggressive and metastatic phenotype. While recent genetic and epigenetic studies have shed new insights into the mechanism of melanoma development, the involvement of regulatory non‐coding RNAs remain unclear. Long non‐coding RNAs (lncRNAs) are a group of endogenous non‐protein‐coding RNAs with the capacity to regulate gene expression at multiple levels. Recent evidences have shown that lncRNAs can regulate many cellular processes, such as cell proliferation, differentiation, migration and invasion. In the melanoma, deregulation of a number of lncRNAs, such as HOTAIR, MALAT1, BANCR, ANRIL, SPRY‐IT1 and SAMMSON, have been reported. Our review summarizes the functional role of lncRNAs in melanoma and their potential clinical application for diagnosis, prognostication and treatment. 相似文献
17.
Changes in odor quality discrimination following recovery from olfactory nerve transection 总被引:4,自引:2,他引:2
Following recovery from olfactory nerve transection, animals regain their
ability to discriminate between odors. Odor discrimination is restored
after new neurons establish connections with the olfactory bulb. However,
it is not known if the new connections alter odor quality perception. To
address this question, 20 adult hamsters were first trained to discriminate
between cinnamon and strawberry odors. After reaching criterion (> or =
90% correct response), half of the animals received a bilateral nerve
transection (BTX) and half a surgical sham procedure. Animals were not
tested again until day 40, a point in recovery when connections are
re-established with the bulb. When BTX animals were tested without food
reinforcement, they could not perform the odor discrimination task. Sham
animals, however, could discriminate, demonstrating that the behavioral
response had not been extinguished during the 40 day period. When
reinforcement was resumed, BTX animals were able to discriminate between
cinnamon and strawberry after four test sessions. In addition, their
ability to discriminate between these two familiar odors was no different
than that of BTX and sham animals tested with two novel odors, baby powder
and coffee. These findings suggest that, after recovery from nerve
transection, there are alterations in sensory perception and that
restoration of odor quality discrimination requires that the animal must
again learn to associate individual odor sensations with a behavioral
response.
相似文献
18.
Masoomeh Etehadnia Doug R. Waterer Karen K. Tanino 《Journal of Plant Growth Regulation》2008,27(4):331-341
The phytohormone abscisic acid (ABA) has been proposed to act as a mediator in plant responses to a range of stresses, including
salt stress. Most studies of ABA response apply ABA as a single dose. This may not resemble the prolonged increasing endogenous
ABA levels that can occur in association with slowly increasing salinity stresses in nature or field situations. Salt stress
response based on method of ABA application was examined in four potato genotypes of varying salt stress resistance: the sensitive
ABA-deficient mutant and its normal sibling, a resistant genotype line 9506, and commercial cultivar ‘Norland’ of moderate
resistance. ABA was applied by root drench at 0, 50, 75, or 100 μM concentrations through a single dose, or by slowly increasing
multiple ABA doses in a sand-based growing system under greenhouse conditions. Salt tolerance was then evaluated after 2 weeks
of exposure to 150–180 mM NaCl stress. The method of ABA application had a marked effect on the responses to salt stress.
Plant responses to the method of ABA application were differentiated according to (1) growth rate, (2) root water content,
and (3) apparent shoot growth response. Under a single dose, growth rate increased in all genotypes under salt stress, whereas
slowly increasing multiple ABA applications generally maintained stable growth rates except in the ABA-deficient mutant where
there was an upward growth trend. Percent root water content was elevated only under slowly increasing multiple ABA doses
in two genotypes, whereas none of the single-dose treatments induced any change. The single ABA dose enhanced vertical growth,
whereas the slowly increasing multiple ABA dose applications enhanced lateral shoot growth. Because exogenous application
is still an artificial system, endogenous ABA was supplied through grafting of ABA-deficient mutant scions onto rootstocks
with known elevated ABA levels. Multiple exogenous ABA applications as low as 50 μM elicited similar shoot water content responses
as grafting treatments without ABA application in the mutant genotype but had no effect on the ABA normal sibling. Shoot dry
weight was significantly increased through grafting over all exogenous ABA treatments. Our study further indicates that the
method of ABA application regime in itself can alter plant responses under salt stress and that certain application regimes
may reflect responses to elevated endogenous levels of ABA. 相似文献
19.
Masoomeh Etehadnia Doug Waterer Hielke De Jong Karen K. Tanino 《Journal of Plant Growth Regulation》2008,27(2):125-140
Tolerance of salt stress in potato (Solanum tuberosum L.) increased when the plants were pre-exposed to low concentrations of salt (salt acclimation). This acclimation was accompanied
by increased levels of abscisic acid (ABA) in the shoot. To further study the role of roots and shoots in this acclimation
process, reciprocal grafts were made between a salt-tolerant (9506) and salt-sensitive ABA(−) mutant and its ABA(+) normal
sibling potato genotype. The grafted plants were acclimated with 75 or 100 mM NaCl for 3 weeks and then exposed to 150–180 mM
NaCl, depending on the salt tolerance of the rootstock. After 2 weeks of exposure to the salt stress, the acclimated and unacclimated
plants were compared for physiologic and morphologic parameters. The response to the salt stress was strongly influenced by
the rootstock. The salt-tolerant 9506 rootstock increased the salt tolerance of scions of both the ABA-deficient mutant and
its ABA(+) sibling. This salt tolerance induced by the rootstock was primarily modulated by salt acclimation and manifested
in the scion via increased plant water content, stem diameter, dry matter accumulation, stomatal conductivity, and osmotic
potential, and is associated with a reduction in leaf necrosis. There was also a pronounced scion effect on the rootstock.
Using 9506 as a scion significantly increased root fresh and dry weights, stem diameter, and root water content of ABA(−)
mutant rootstocks. Specific evidence was found of the role of exogenous ABA in the enhancement of water status in grafted
plants under salt stress beyond that of grafting alone. This was verified by more positive stomatal conductivity and upward
water flow in ABA-treated grafted and nongrafted plants and the absence of upward water flow in nontreated grafted plants
through NMR imaging. Grafting using either salt-tolerant scions or rootstocks with inherently high ABA levels may positively
modify subsequent responses of the plant under salt stress. 相似文献
20.
There is increasing evidence that temperature, in addition to photoperiod, may be an important factor regulating bud dormancy.
The impact of temperature during growth cessation, dormancy development, and subsequent cold acclimation was examined in four
hybrid poplar clones with contrasting acclimation patterns: ‘Okanese’—EARLY, ‘Walker’—INT1, ‘Katepwa’—INT2, and ‘Prairie Sky’—LATE.
Four day–night temperature treatments (13.5/8.5, 18.5/13.5, 23.5/8.5, and 18.5/3.5°C) were applied during a 60-day induction
period to reflect current and predicted future annual variation in autumn temperature for Saskatoon, SK. Warm night temperature
(18.5/13.5°C) strongly accelerated growth cessation, dormancy development, and cold acclimation in all four clones. Day temperature
had the opposite effect of night temperature. Day and night temperatures appeared to act antagonistically against each other
during growth cessation and subsequent dormancy development and cold acclimation. Growth cessation, dormancy development,
and cold acclimation in EARLY and LATE were less affected by induction temperature than INT1 and INT2 suggesting that genotypic
variations exist in response to temperature. Separating specific phenological stages and the impact by temperature on each
clone revealed the complexity of fall phenological changes and their interaction with temperature. Most importantly, future
changes in temperature may affect time to growth cessation, subsequently altering the depth of dormancy and cold hardiness
in hybrid poplar. 相似文献