全文获取类型
收费全文 | 1077篇 |
免费 | 56篇 |
专业分类
1133篇 |
出版年
2022年 | 8篇 |
2021年 | 12篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 24篇 |
2014年 | 45篇 |
2013年 | 64篇 |
2012年 | 52篇 |
2011年 | 74篇 |
2010年 | 35篇 |
2009年 | 45篇 |
2008年 | 66篇 |
2007年 | 94篇 |
2006年 | 71篇 |
2005年 | 79篇 |
2004年 | 66篇 |
2003年 | 63篇 |
2002年 | 51篇 |
2001年 | 15篇 |
2000年 | 12篇 |
1999年 | 10篇 |
1998年 | 13篇 |
1997年 | 18篇 |
1996年 | 19篇 |
1995年 | 9篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 12篇 |
1991年 | 7篇 |
1990年 | 11篇 |
1989年 | 12篇 |
1988年 | 2篇 |
1987年 | 8篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 14篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1980年 | 10篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1973年 | 2篇 |
1970年 | 2篇 |
1960年 | 1篇 |
排序方式: 共有1133条查询结果,搜索用时 0 毫秒
991.
Sei-itsu Murota Ikuo Morita Susumu Tsurufuji Hiroshi Sato Kazuo Sugio 《Prostaglandins & other lipid mediators》1978,15(2):297-301
The effects of prostaglandin I2, 6-ketoprostaglandin F1α, prostaglandin E1 and thromboxane B2 on the vascular permeability response in rat carrageenin granuloma were studied with the aid of 131I- and 125I-human serum albumin as indicators for the measurement of local vascular permeability.A single injection of 5 μg of prostaglandin I2 methyl ester or I2 sodium salt into the locus of the granulomatous inflammation elevated local vascular permeability 2.0–2.5 times over the control within 30 min. The potency was equal to that of the positive control prostaglandin E1 which has been known to be the most potent mediator in this index among several candidate prostaglandins for chemical mediator of inflammation. The other prostaglandin and thromboxane B2 tested were essentially inactive. 相似文献
992.
Masanobu Tanaka Ikuo Morita Syun Hirakawa Sei-itsu Murota 《Prostaglandins & other lipid mediators》1981,21(1):83-86
Homogenate of human uterine cervix at delivery were incubated with radioactive arachidonic acid. A major metabolite (conversion rate, approx. 20%) was identified with 6-ketoprostaglandin F1α, a metabolite of prostacyclin. The 6-ketoprostaglandin F1α production in the ripening cervix was more than 6 times per wet weight and 37 times per DNA as much as that in the non-pregnant cervix. 相似文献
993.
Ikuo Morita Yuko Nakayama Sei-itsu Murota 《Prostaglandins & other lipid mediators》1979,18(4):507-517
Fibroblasts derived from a rat carrageenin granuloma were cultured in the presence of radioactive arachidonic acid, palmitic acid and linoleic acid. More than 90% of each labeled fatty acid was incorporated into a phospholipid fraction by the cells in 18 hrs. Arachidonic acid was evenly incorporated into phosphatidylcholine and phosphatidylethanolamine, while both palmitic acid and linoleic acid were almost entirely incorporated into phosphatidylcholine. The position of phosphatidylcholine where the fatty acids were incorporated was different for each fatty acid. The ratio of the amount of fatty acid incorporated into the 2-position to the amount incorporated into the 1-position of phosphatidylcholine for each fatty acid was >90% for arachidonic acid, 2:1 for palmitic acid and 5:1 for linoleic acid. In the case of phosphatidylethanolamine, most arachidonic acid (>90%) was incorporated into the 2-position. PGF2α caused the stimulation of arachidonic acid release but not of palmitic acid and linoleic acid from pre-labeled fibroblasts.The serum in the medium was completely replaceable by bovine serum albumin. The effect of PGF2α increased with an increasing concentration of bovine serum albumin, suggesting that serum only acts as a ‘trap’ for released arachidonic acid. The effect of PGF2α was greater than bradykinin, and no synergistic effect was seen, although an additive effect was observed.The effect of PGF2α depended on the concentration of calcium ions under magnesium-supplemented conditions. 相似文献
994.
995.
Ikuo Igarashi Francis Kimani Njonge Yutaro Kaneko Yoshihiro Nakamura 《Experimental parasitology》1998,90(3):290-293
Igarashi, I., Njonge, F. K., Kaneko, Y., and Nakamura, Y. 1998.Babesia bigemina:In vitroandin vivoeffects of curdlan sulfate on growth of parasites.Experimental Parasitology90, 290–293. 相似文献
996.
Raman spectra were measured for poly(L -histidine) in H2O, poly(L -histidine-d2 and -d3) in D2O, L -histidine in H2O, L -histidine-d3 (and d4) in D2O, and 4-methylimidazole in H2O with various pH (or pD) values. The Raman scattering peaks observed for these samples were ascribed to the neutral and positively charged imidazole groups on the basis of the spectral changes due to the pH variation and to the deuterium substitution of the imino protons. The vibrational modes of these peaks were deduced from the normal coordinate analysis made on the positively charged and neutral 4-ethylimidazoles. The Raman scattering peaks from the imidazole groups in the neutral form clearly indicate that these imidazole groups exist in the equilibrium between the two tautomeric forms, the 1-N protonated from (tautomer I) and the 3-N protonated one (tautomer II). For example, the breathing vibration of the 1-N protonated form is observed at 1282 cm?1 for L -histidine and at 1304 cm?1 for 4-methylimidazole, while the breathing vibration of the 3-N protonated form is observed at 1260 cm?1 for L -histidine and 4-methylimidazole. From the temperature dependence of the relative intensities of the tautomer I peak to that of the tautomer II, it was concluded that the tautomer I is energetically more stable than the tautomer II, and the ΔH value is 1.0 ± 0.3 kcal/mol for L -histidine and 0.4 ± 0.1 kcal/mol for 4-methylimidazole. Poly(L -histidine) with the neutral imidazole side chains shows the amide I peak at 1672 cm?1, indicating that the sample assumes the antiparallel pleated-sheet structure. Poly(L -Ala75L -His25) and poly(L -Ala50L -His50) were found to take the α-helical and β-form conformations, respectively. 相似文献
997.
Iwao Koyama Mari Yakushijin Takanori Nakajima Shigeru Hokari Shin-ichiro Kawai Kohtaro Oh-Ie Ikuo Inoue Kiyohiko Negishi Shigehiro Katayama Tsugikazu Komoda 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》1998,121(4):417-423
We found previously that human bone alkaline phosphatase (AP) was glycated by aseptic incubation with glucose, and partially broken down by reactive oxygen species. In this study, we examined whether selective in vivo glycation of AP molecules occurred in bone tissue, using experimental diabetic rats induced by streptozotocin and spontaneously diabetic rats. Additionally, the effects of hyperlipidemia on bone AP activity were examined. Serum AP activity was significantly elevated after incipient onset of diabetes, and the increased activity originated from the intestinal isozyme. High levels of intestinal AP activity were also observed in rats with hyperlipidemia induced by feeding high-fat or high-fructose chow, but the AP activity in bone tissues was maintained at a constant level. AP activity in bone was reduced after the onset of diabetes. The resulting bone AP molecule bound to an aminophenylboronic acid column, which had affinity for glycated proteins, and contained smaller molecular sizes than the native bone AP. These results suggest that elevated levels of serum AP activity originated from the intestinal isozyme accompanied with hyperlipidemia induced by diabetes. In contrast, the reduced serum levels of AP activity in diabetic rats might be dependent on inactivation of bone AP, which was glycated, followed by partial breakdown of bone AP molecules, possibly due to reactive oxygen species. 相似文献
998.
Takayuki Negishi Toshikazu Tominaga Yoshiyuki Ishii Shigeru Kyuwa Ikuo Hayasaka Yoichiro Kuroda Yasuhiro Yoshikawa 《Experimental Animals》2004,53(4):391-394
We compared the toxicokinetics of bisphenol A (BPA) among three animal species: rats, cynomolgus monkeys and chimpanzees. Rats and monkeys were administered BPA orally or subcutaneously at 10 or 100 mg/kg body weight, while chimpanzees were administered only 10 mg/kg of BPA. BPA in serum was measured by ELISA. In oral administration of BPA at 10 mg/kg, both C(max) and AUC were rats < chimpanzee < monkeys. In oral administration of BPA at 100 mg/kg, both C(max) and AUC were rats < monkeys. Subcutaneous BPA administrations also revealed similar results, although the values of toxicokinetic parameters in subcutaneous administration were higher than those in oral administration. These results suggest that orally or subcutaneously administered BPA in primates is more easily absorbed than that in rats. We conclude that there are considerable differences in distribution, metabolism, and excretion of BPA between rodents and primates. 相似文献
999.
Does ADP-Ribosylation of Proteins in Nuclei Contribute to Ectoderm Cell Differentiation in Sea Urchin Embryos? 总被引:3,自引:3,他引:0
Yasuyuki Kamata Akiko Fujiwara Shigehisa Furuya Ikuo Yasumasu 《Development, growth & differentiation》1993,35(1):89-98
In nuclei of sea urchin embryos, marked increase in ADP-ribosyltransferase activity followed by its decrease occurrs in the pre-hatching and post-hatching periods with peaks of activity at the morula and gastrula stages. Increase in its activity was blocked by cycloheximide in the pre- and post-hatching periods and by actinomycin D only in the post-hatching period. Embryo wall cells (ectoderm cells) isolated from gastrulae exhibited markedly higher activity of this enzyme than archenteron cells and mesenchyme cells. Probably, the increase in the activity of this enzyme in the post-hatching period results from expression of the gene for this enzyme mainly in ectoderm cells. In the post-hatching period, the activity increased more in animalized embryos than in normal ones, and increased little in vegetalized embryos. 3-Aminobenzamide (3-ABA), as well as luminol and nicotinamide, inhibited formation of ectoderm structures more than that of endoderm structures, such as the archenteron, in normal and animalized embryos, but had no appreciable effect on morphogenesis in vegetalized embryos. The reaction catalyzed by ADP-ribosyltransferase probably contributes to ectoderm cell differentiation. Treatment of embryos with 3-ABA in the pre-hatching period had little inhibitory effect on the morphogenesis in the post-hatching period, though it caused death of many embryos. 相似文献
1000.
The conjugation of RGDS peptide with CM-chitin augments the peptide-mediated inhibition of tumor metastasis 总被引:4,自引:0,他引:4
Hiroyuki Komazawa Ikuo Saiki Yu Igarashi Ichiro Azuma Seiichi Tokura Masayoshi Kojima Atsushi Orikasa Mitsunori Ono Isamu Itoh 《Carbohydrate polymers》1993,21(4):299-307
A water soluble 6-O-carboxymethyl chitin (CM-chitin) containing cell adhesive Arg-Gly-Asp-Ser (RGDS) sequence, i.e. CM-chitin-RGDS conjugate was synthesized, and the inhibitory effects of this compound on lung or liver metastasis of lung-metastatic B16-BL6 melanoma or liver-metastatic L5178Y-ML25 lymphoma cells in mice was examined. CM-chitin-RGDS showed the inhibitory effects on lung metastasis of melanoma cells in a dose-dependent manner (ranging from 100 to 1000 μg) and on liver metastasis of lymphoma cells. A mixture of CM-chitin and RGDS peptide or CM-chitin alone did not show any inhibitory effect on experimental lung metastasis as compared with the conjugate CM-chitin-RGDS on a molar basis. GRGDS peptide, however, required a higher dose (3000 μg) to obtain a sufficiently antimetastatic effect. The in-vitro tumor invasion study showed that CM-chitin-RGDS was apparently more effective for the inhibition of tumor cell penetration into reconstituted basement membrane Matrigel than RGDS or the mixture of RGDS and CM-chitin on a molar basis. Intermittent i.v. administration of CM-chitin-RGDS after the inoculation of B16-BL6 cells caused significant inhibition of spontaneous lung metastasis produced by intrafootpad injection of tumor cells as compared with the multiple administration of RGDS, CM-chitin or untreated control. These results demonstrate the importance of the conjugation of RGDS peptide with CM-chitin as a polymeric carrier for the increased therapeutic potential to cancer metastasis, thus implying a possibility that RGDS-polymer conjugation may lead to the prolongation of antimetastatic action of RGDS peptide in vivo. 相似文献