全文获取类型
收费全文 | 500篇 |
免费 | 49篇 |
出版年
2023年 | 6篇 |
2022年 | 4篇 |
2021年 | 12篇 |
2020年 | 13篇 |
2019年 | 3篇 |
2018年 | 12篇 |
2017年 | 4篇 |
2016年 | 27篇 |
2015年 | 26篇 |
2014年 | 20篇 |
2013年 | 34篇 |
2012年 | 36篇 |
2011年 | 39篇 |
2010年 | 24篇 |
2009年 | 19篇 |
2008年 | 34篇 |
2007年 | 28篇 |
2006年 | 26篇 |
2005年 | 20篇 |
2004年 | 18篇 |
2003年 | 20篇 |
2002年 | 18篇 |
2001年 | 14篇 |
2000年 | 13篇 |
1999年 | 12篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有549条查询结果,搜索用时 15 毫秒
21.
22.
23.
Phenanthropyran derivatives from Phalaenopsis equestris 总被引:1,自引:0,他引:1
Two phenanthropyran derivatives, 3-methoxy-2,7-dihydroxy-5H-phenanthro[4,5-bcd]pyran and 2,3,7-trihydroxy-5H-phenanthro[4,5-bcd]pyran were isolated from the orchid Phalaenopsis equestri. Their chemical structures were elucidated from spectroscopic (NMR, MS etc.) analyses. 相似文献
24.
N Tanaka T Tanaka T Fujioka H Fujii K Mihashi K Shimomura K Ishimaru 《Phytochemistry》2001,57(8):1287-1291
An ellagic acid derivative, 3,3'-di-O-methylellagic acid 4-(5"-acetyl)-alpha-L-arabinofuranoside, and two iridoid glucosides, 6alpha-dihydrocornic acid and 6beta-dihydrocornic acid, were isolated from Cornus capitata adventitious roots cultured in Murashige-Skoog (Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant. 15, 473-487) liquid medium containing 10 microM CuSO(4). Three known related metabolites, i.e. stenophyllin H1, dihydrocornin and cornin were also produced in the root cultures. The chemical structures were characterized by analysis of spectroscopic data. 相似文献
25.
Sun L Tamaki H Ishimaru T Teruya T Ohta Y Katsuyama N Chinen I 《Bioscience, biotechnology, and biochemistry》2004,68(12):2613-2615
Seven-week old female rats fed restricted foods including the fish oils Docosahesaenoic Acid (DHA) and Eicosapentaenoic Acid (EPA) and perilla oil with food intake decreased by 50%, had increases of fracture force and bone mineral density (BMD) and decreases in levels of Deoxypiridinoline (Dpd) and Calcium (Ca) in the urine, compared with those of rats with osteoporosis due to restricted soy bean oil food intake. Therefore, the fish oils DHA and EPA and perilla oil depressed excretion of urinary Ca and inhibited osteoporosis due to restricted food intake. 相似文献
26.
Tamaki H Sun L Ohta Y Katsuyama N Ishimaru T Chinen I 《Bioscience, biotechnology, and biochemistry》2004,68(7):1578-1580
Running at 0.7 km/h for 10 min every day inhibited development of osteoporosis caused by protein deficient (PD) food intake. Urine alkaline phosphatase (ALP), a marker of bone formation osteoporosis, was not elevated in rats fed PD, when the osteoporosis was inhibited by running. Estrogen supplementation increased bone-breaking energy (BBE), but did not increase bone mineral density (BMD), and did not decrease urinary ALP levels. 相似文献
27.
28.
El-Sayed NM Ghedin E Song J MacLeod A Bringaud F Larkin C Wanless D Peterson J Hou L Taylor S Tweedie A Biteau N Khalak HG Lin X Mason T Hannick L Caler E Blandin G Bartholomeu D Simpson AJ Kaul S Zhao H Pai G Van Aken S Utterback T Haas B Koo HL Umayam L Suh B Gerrard C Leech V Qi R Zhou S Schwartz D Feldblyum T Salzberg S Tait A Turner CM Ullu E White O Melville S Adams MD Fraser CM Donelson JE 《Nucleic acids research》2003,31(16):4856-4863
29.
Hou X Gobeil F Marrache AM Quiniou C Brault S Checchin D Bernier SG Sennlaub F Joyal JS Abran D Peri K Varma DR Chemtob S 《American journal of physiology. Regulatory, integrative and comparative physiology》2003,284(4):R928-R935
Oxidant stress contributes to the pathogenesis of hypoxic-ischemic encephalopathies. Platelet-activating factor (PAF) is generated during oxidant stress. We studied the vasomotor mode of actions of PAF on periventricular (PV) microvessels of fetal ( approximately 75% of term), newborn (1-3 days), and adult pigs. PAF constricted PV microvessels from fetal (29.27 +/- 2.6%) and newborn (22.14 +/- 3.2%) pigs but was ineffective in adults (<2.5%). Specific [(3)H]PAF binding was greater in fetus and newborn than in adults; a concordant developmental PAF-induced inositol phosphate formation was observed. PAF-induced vasoconstriction was abrogated by thromboxane A(2) (TXA(2)) synthase and receptor inhibitors, calcium channel blockers, and by removal of endothelium; vasoconstriction to TXA(2) mimetic U-46619 did not differ with age. Immunoreactive TXA(2) synthase expression and PAF-evoked TXA(2) formation revealed a fetus> newborn>adult profile. Thus the greater PAF-induced PV microvascular constriction in younger subjects seems attributable to greater PAF receptor density and mostly secondary to TXA(2) formation from endothelium. The resulting decrease in blood flow may contribute to the increased vulnerability of the PV brain regions to oxidant stress-induced injury in immature subjects. 相似文献
30.
Ishimaru T Hatanaka S Yata T Horikawa I Tsukatani T Nishimura T Miwa T Furukawa M 《Chemical senses》2002,27(8):711-717
Intravenous olfaction is a unique stimulation method often used in Japan to diagnose olfactory disturbances. Odorant is injected into a vein and transported by blood flow and respiration to the upper air tract. The intravenous olfaction might allow the potential at the frontal scalp to be recorded without contamination from electromyograms, such as those caused by sniffing. We injected Alinamin (thiamine propyldisulphide) into healthy subjects according to a standard protocol for clinical intravenous olfaction testing and we simultaneously recorded potential changes at the frontal scalp. When Alinamin was injected into the right median cubital vein over a 20 s period, the potential changes with gamma-band oscillations were detected 17.6 +/- 6.7 s (mean +/- SD) after the start of the injection. The main frequency component of this gamma-band oscillation is 30-160 Hz. The gamma-band oscillation elicited by intravenous olfactory stimulation (VOP) was similar to the induced wave of the olfactory bulb. Mapping the VOPs on the frontal scalp of a subject with less developed frontal sinuses and the relation between the thickness of the frontal sinuses and VOP amplitude suggest an intracranial source, possibly the olfactory bulb. The gamma-band potential at the frontal scalp is a useful measure of central disturbance. 相似文献