全文获取类型
收费全文 | 186篇 |
免费 | 27篇 |
国内免费 | 1篇 |
专业分类
214篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 11篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 6篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 10篇 |
1999年 | 2篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1972年 | 6篇 |
1971年 | 3篇 |
1970年 | 4篇 |
1968年 | 4篇 |
1967年 | 2篇 |
1966年 | 2篇 |
1940年 | 1篇 |
1939年 | 1篇 |
1938年 | 1篇 |
1936年 | 3篇 |
1935年 | 1篇 |
1933年 | 2篇 |
1931年 | 2篇 |
排序方式: 共有214条查询结果,搜索用时 0 毫秒
1.
The aims of this study were to investigate the control of fatty acid synthesis and its relationship to surfactant production in the fetal lung during alteration of hormonal and substrate conditions. Lung explants from 18 day fetuses (term = 22 days) which were cultured 2 days in the presence of 10 mM lactate showed parallel acceleration of de novo fatty acid synthesis (3H2O incorporation) and [14C]choline incorporation into disaturated phosphatidylcholine (DSPC) compared to culture of explants in glucose. Both the cultured and fresh explants were resistant to the classical short term (4 h) cAMP inhibition of fatty acid synthesis with 3 mM dibutyryl cAMP or 0.5 mM aminophylline. In the cultured explants short term cAMP elevation increased DSPC production, and long term (2 day) cAMP elevation caused a further increase in DSPC synthesis and also stimulated fatty acid synthesis. In cultured explants from 17 day fetuses, dexamethasone (0.1 microM) caused a synergistic increase with aminophylline in both fatty acid synthesis and DSPC production whereas, in explants from 18 day fetuses, dexamethasone inhibited both processes and reduced the level of stimulation of DSPC and fatty acid synthesis seen with aminophylline alone. Dexamethasone also reduced the stimulation of both DSPC and fatty acid synthesis produced in the culture of 18 day explants with bacitracin (0.5 mg/ml), whereas the combination of bacitracin and aminophylline resulted in a synergistic increase in DSPC production. Culture with glucagon (0.1 microM) also stimulated DSPC synthesis but at physiological levels insulin had no effect on either DSPC or fatty acid synthesis. These data show that lung fatty acid synthesis exhibits unique features of fatty acid synthesis regulation compared to other lipogenic tissues and also suggest a link between de novo fatty acid synthesis and surfactant production during the critical period of accelerated lung maturation. 相似文献
2.
The serologic types of 265 isolates of Pasteurella multocida collected from 50 species of wild birds and seven species of wild mammals over a 22-yr period were determined with the gel diffusion precipitin test. Antigens prepared from these isolates reacted with reference P. multocida antisera representing serotypes 1, 2, 3, 4, 5, 6, 7, 8, 12, and 15. Antigens from some isolates reacted slightly with antisera from more than one serotype. Overall, gel precipitin reactions involving serotype 1 (65%) and 3 (20%) were the most prevalent. 相似文献
3.
4.
H J Enfiejian N L Chiaia G J Macdonald R W Rhoades 《Somatosensory & motor research》1989,6(5-6):537-552
Neonatal transection results in a marked reduction of the number of trigeminal (V) ganglion cells that contribute axons to the regenerate infraorbital nerve (ION; Jacquin and Rhoades, 1985; Chiaia et al., 1987). Such lesions also produce a profound deafferentation of the V brain stem complex that appears to spare the innervation of layers I and II of subnucleus caudalis (SpC) by substance-P-positive (SP-positive) primary afferents (Jacquin and Rhoades, 1985; Rhoades et al., 1988). In the present study, we combined retrograde tracing with immunocytochemistry to determine whether neonatal transection of the ION alters the percentage of SP-positive V ganglion cells that contribute axons to this V branch upon regeneration. In V ganglia ipsilateral to the intact ION (n = 8), 11.6% +/- 3.2% of the cells labeled after application of true blue (TB) to the ION were also SP-positive. In ganglia ipsilateral to the neonatally damaged nerve (n = 8), 18.6% +/- 4.7% of the cells labeled after application of TB to the regenerate ION were also SP-positive (p less than 0.001). We also compared the SP content of intact ganglia (n = 10) with that of ganglia ipsilateral to the damaged nerve (n = 10) by means of radioimmunoassay. The normal V ganglia contained (mean +/- SD) 3496 +/- 774 pg SP/mg protein. The value for the ganglia ipsilateral to the damaged nerve was 5533 +/- 1746 pg SP/mg protein (p less than 0.01). There was no significant difference between SP levels on the control and partially deafferented sides of the brain stem in neonatally nerve-damaged adult rats. In one additional experiment, we injected TB into both vibrissa pads of seven rats on the day of birth prior to transection of the ION. After an 8-hr delay, the nerve on one side was then cut and allowed to regenerate, and both V ganglia were then processed for immunocytochemistry. On the nerve-damage side, 25.8% of the TB-labeled cells were SP-positive. The value for the intact side was 12.0% (p less than 0.000001). This result demonstrated that the lesion-induced change in the percentage of SP-positive ION cells was not the result of either late-growing axons from SP-positive ganglion cells that may have been missed by our nerve cuts or collateral sprouting into the regenerate ION by undamaged SP-positive ganglion cells. 相似文献
5.
IL-4 down-regulates IL-1 and TNF gene expression in human monocytes 总被引:37,自引:0,他引:37
R Essner K Rhoades W H McBride D L Morton J S Economou 《Journal of immunology (Baltimore, Md. : 1950)》1989,142(11):3857-3861
6.
Mutations of bacteriophage T5 were isolated which lack one or more of the natural single-chain interruptions that occur in the mature DNA of this virus. Interruption-deficient mutants were detected by screening survivors of hydroxylamine mutagenesis for altered DNA structure by electrophoresis in agarose slab gels. Over 60 independent mutants were isolated from a survey of approximately 800 phages particles. All of the mutants were viable and could be grouped into two classes. Mutants in one class lacked one of the localized sites where interruptions occur in T5 DNA. To date, mutants that affect five different sites have been obtained. Mutants in the other class were essentially free from interruptions or had a reduced frequency of interruptions throughout the genome. The members of this class included several amber mutants. Complementation tests indicated that at least two genes are required for the presence of interruptions in mature T5 DNA. 相似文献
7.
8.
Reactive oxygen species alter contractile properties of pulmonary arterial smooth muscle 总被引:2,自引:0,他引:2
R A Rhoades C S Packer D A Roepke N Jin R A Meiss 《Canadian journal of physiology and pharmacology》1990,68(12):1581-1589
Reactive oxygen species alter pulmonary arterial vascular tone and cause changes in pulmonary vascular resistance. The objective of this investigation was to determine direct effects of oxygen radicals on the contractile properties of pulmonary arterial smooth muscle. Isolated pulmonary arterial rings from Sprague-Dawley rats were placed in tissue baths containing Earle's balanced salt solution (gassed with 95% O2 - 5% CO2, 37 degrees C, pH 7.4). Vessels were contracted with 80 mM KCl to establish maximum active force production (Po). All other responses were normalized as percentages of Po for comparative purposes. Reactive oxygen metabolites were generated enzymatically with either the xanthine oxidase (XO) reaction or the glucose oxidase (GO) reaction, or hydrogen peroxide (H2O2) was added directly to the muscle bath. Exposure to XO, GO, or to H2O2 resulted in a contractile response that was sustained during the 30-min exposure period. The muscle fully relaxed following removal of the reactive oxygen species. Resting tension remained unchanged throughout the experimental period, suggesting no functional change in membrane potential. The contractile response was dose dependent and was not prevented by either cyclooxygenase or lipoxygenase inhibition, or by removal of the endothelium. Pretreatment of vessels with superoxide dismutase (SOD) partially blocked the XO-induced contraction, while mannitol or deferoxamine had no effect on the response to XO. However, pretreatment with catalase (CAT) completely blocked the XO-induced contraction. These data suggest that superoxide ions and hydrogen peroxide are the major causative agents. Following O2-radical exposure, vessels showed a decrease in contractile responsiveness to 80 mM KCl (recovery response), suggesting damage to the smooth muscle cells.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
9.
R A Rhoades 《Journal of applied physiology》1975,38(3):513-516
The relative utilization of [U-14C]glucose and [1-14C]palmitate was examined in lung slices of male Long Evans hooded rats fed ad libitum and starved for 72 h. Food deprivation (72-h fast) significantly decreased [U-14C]flucose oxidation and incorporation into lung lipids. Glucose incorporation into phospholipid-fatty acid (53%) was, in proportion, more markedly reduced than into phospholipid-gluceride glycerol (33%), suggesting that glucose was being conserved for the formation of alpha-glycerol phosphate. (1-14C) palmitate utilization following fasting showed a significant 40% increase in oxidation, and a significant 16% increase in phospholipids, indicating preferential utilization of fatty acids over glucose. Phospholipid fatty acid composition, surface tension measurements and volume-pressure curves were not affected by fasting. Khe data indicate that glucose and palmitate metabolism are interrelated, and that the relative utilization of these substrates is changed to maintain essential lung lipids during an altered physiologic state. 相似文献
10.