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131.
Cell death by reactive oxygen species generated from water-soluble cationic metalloporphyrins as superoxide dismutase mimics. 总被引:3,自引:0,他引:3
T Ohse S Nagaoka Y Arakawa H Kawakami K Nakamura 《Journal of inorganic biochemistry》2001,85(2-3):201-208
We investigated the effect on cell death of reactive oxygen species induced by water-soluble cationic metalloporphyrins with superoxide dismutase (SOD) activity. The SOD activity of 5,10,15,20-tetrakis(4-N-methylpyridyl)]porphine (MPy(4)P) containing Fe, Mn or Cu was measured using a cytochrome c assay by the xanthine/xanthine oxidase system and stopped-flow kinetic analysis. Cell viability of four cell lines treated with metalloporphyrins, mitomycin c (MMC), or cisplatin was estimated by a trypan blue exclusion assay. FeMPy(4)P with a high SOD activity showed a significant cytotoxicity compared with MMC and cisplatin, while CuMPy(4)P without SOD activity exhibited no cytotoxicity. However, MnMPy(4)P showing an SOD activity as high as that of FeMPy(4)P did not indicate cytotoxicity. These findings suggest that FeMPy(4)P as SOD mimic converts intracellular O2(*-) to H(2)O(2) and that it rapidly reacts with H(2)O(2) to form *OH, causing DNA damage and inducing cell death. On the other hand, MnMPy(4)P did not participate in the Fenton reaction, so that DNA damage in the cells treated with MnMPy(4)P was not observed. In addition, the cytotoxicity by the metalloporphyrin was inversely correlated with the SOD activity of the cells and the selective damage at cellular and DNA levels was confirmed. We believe that for an anticancer drug with antioxidant ability O(2)(*-) is useful as a target molecule to induce selective cell death between cancer and normal cells and that metalloporphyrins showing SOD activity and Fenton-like reaction are a new class of anticancer agents. 相似文献
132.
Hiroyuki Mochizuki Yasushi Ohki Hirokazu Arakawa Masahiko Kato Kenichi Tokuyama Akihiro Morikawa 《Journal of applied physiology》2002,92(1):155-161
We evaluated the mechanism of the anti-asthmatic effect of inhaled indomethacin (Indo) by using an animal model (guinea pigs) of airway inflammation. After being exposed to either ozone or room air at identical flow rates (5 l/min) for 2 h, guinea pigs were anesthetized, tracheostomized, and lung resistance (RL) was subsequently measured. Guinea pigs inhaled either saline or Indo (1.5 mg/ml) for 1 min before undergoing an ultrasonically nebulized distilled water (UNDW) inhalation test. RL increased significantly after 10 min of UNDW inhalation in the room air and ozone groups but more so in the ozone group. This increase in RL was significantly suppressed by pretreatment with Indo. In the morphometric assessment of airway mucosa, a significant swelling of the epithelial cells after UNDW inhalation was observed in both the room air and ozone groups but especially so in the ozone group. This increase was also suppressed with Indo pretreatment. These results suggest that the increase in RL and the swelling of airway epithelial cells induced by inhaled UNDW in ozone-exposed guinea pigs was suppressed by pretreatment of inhaled Indo and that this suppression may be one of the reasons for the anti-asthmatic effect of inhaled Indo. 相似文献
133.
Conidiomata of the white root rot fungus were produced in axenic culture under near-ultraviolet light radiation. Pieces of
sterilized Japanese pear twigs were placed on 7-day-old oatmeal agar culture in plates. The plates were further incubated
for 5 days and then illuminated by near-ultraviolet light. Synnemata developed on the twigs within 5 weeks in 19 of 20 isolates
tested, and conidia were observed in 12 of the 19 isolates. The synnemata and conidia produced were morphologically identical
to those of Dematophora necatrix.
Received: October 29, 2001 / Accepted: March 11, 2002 相似文献
134.
Abstract: Budded particles of nucleopolyhedrovirus (NPV) were found to infect perorally the 4th (prefinal) instar larvae of Bombyx mori L. that were treated by an optical brightener, Tinopal UNPA-GX (Tinopal). Host larvae were fed a diet containing 0.3% (w/w) Tinopal on day 1 in the 4th instar and then fed a diet contaminated by budded particles of NPV (1.0 × 106 TCID50 U/larva) that was pathogenic to B . mori (BmNPV) on day 2 (inoculation schedule 1). Another set of host larvae was fed a diet containing BmNPV budded particles (2.5 × 106 TCID50 U/larva) together with 0.3% (w/w) Tinopal on day 1 in the 4th instar (inoculation schedule 2). Host larvae treated by both schedules died of viral infection. The operation of schedule 2 is simpler than that of schedule 1, although the former required higher doses of the virus for satisfactory infection. We inoculated a baculovirus vector carrying human serum albumin (HSA) gene into 4th instar B . mori larvae by schedule 1. Recombinant HSA was detected in the homogenate of host larvae 4 days after inoculation. The peroral inoculation of BmNPV budded particles aided by Tinopal may thus lead to industrial pharmaceutical production using a baculovirus vector for large numbers of insect hosts. 相似文献
135.
T Arakawa 《Analytical biochemistry》1985,144(1):267-268
Larger elution volumes of proteins in gel filtration in the presence of polyethylene glycol than in its absence were explained in terms of the unfavorable interactions between polyethylene glycol and both the proteins and the gel matrix. This should favor the protein molecules being in the cavity of the gel matrix, leading to their slower elution, since, in this situation, the unfavorable interactions are decreased. 相似文献
136.
Dehydration-induced conformational transitions in proteins and their inhibition by stabilizers. 总被引:17,自引:1,他引:16 下载免费PDF全文
Dehydration of proteins results in significant, measurable conformational changes as observed using Fourier-transform infrared spectroscopy and resolution-enhancement techniques. For several proteins these conformational changes are at least partially irreversible, since, upon rehydration, denaturation and aggregation are observed. The presence of certain stabilizers inhibited these dehydration-induced transitions; the native structure was preserved in the dried state and upon reconstitution. Conformational transitions were also observed in a model polypeptide, poly-L-lysine, after lyophilization and were inhibited with the addition of stabilizing cosolutes. The ability of a particular additive to preserve the aqueous structure of dehydrated proteins and poly-L-lysine upon dehydration correlates directly with its ability to preserve the activity of lactate dehydrogenase, a labile enzyme, during drying. 相似文献
137.
138.
139.
Nobuhiko Arakawa Choten Inagaki Tomiko Kitamura Sumiko Fujiki Masao Fujimaki 《Bioscience, biotechnology, and biochemistry》2013,77(7):1445-1447
A two-dimensional mapping analysis was performed by HPLC for 4 kinds of standard galactosyllactoses (GLs, trisaccharide) which were assumed to be produced from lactose (galactopyranosylβ1→4 glucopyranose) in yogurt during the fermentation of lactic acid bacteria. After the pyridylamination of GLs, they were analyzed by HPLC in the reverse-phase (RP) and anion-exchange (AE) modes. The retention times of each peak obtained were converted to glucose units (GU) in RP mode for the pyridylaminated isomaltooligosaccharides (G1-3) and to relative retention time (RRT) in AE mode against pyridylaminated-isomaltotriose, and then the address data [GU, RRT] were plotted on a graph. This two-dimensional mapping method was found useful for a rapid qualitative evaluation of the chemical structure of trisaccharides formed in yogurt. 相似文献
140.
Makoto Watanabe Yu Kamimaki Marino Mori Shigeaki Okabe Izumi Arakawa Yoshiyuki Kinose Satoshi Nakaba Takeshi Izuta 《Journal of plant research》2018,131(6):907-914
Ozone is an air pollutant that negatively affects photosynthesis in woody plants. Previous studies suggested that ozone-induced reduction in photosynthetic rates is mainly attributable to a decrease of maximum carboxylation rate (Vcmax) and/or maximum electron transport rate (Jmax) estimated from response of net photosynthetic rate (A) to intercellular CO2 concentration (Ci) (A/Ci curve) assuming that mesophyll conductance for CO2 diffusion (gm) is infinite. Although it is known that Ci-based Vcmax and Jmax are potentially influenced by gm, its contribution to ozone responses in Ci-based Vcmax and Jmax is still unclear. In the present study, therefore, we analysed photosynthetic processes including gm in leaves of Siebold’s beech (Fagus crenata) seedlings grown under three levels of ozone (charcoal-filtered air or ozone at 1.0- or 1.5-times ambient concentration) for two growing seasons in 2016–2017. Leaf gas exchange and chlorophyll fluorescence were simultaneously measured in July and September of the second growing season. We determined the A, stomatal conductance to water vapor and gm, and analysed A/Ci curve and A/Cc curve (Cc: chloroplast CO2 concentration). We also determined the Rubisco and chlorophyll contents in leaves. In September, ozone significantly decreased Ci-based Vcmax. At the same time, ozone decreased gm, whereas there was no significant effect of ozone on Cc-based Vcmax or the contents of Rubisco and chlorophyll in leaves. These results suggest that ozone-induced reduction in Ci-based Vcmax is a result of the decrease in gm rather than in carboxylation capacity. The decrease in gm by elevated ozone was offset by an increase in Ci, and Cc did not differ depending on ozone treatment. Since Cc-based Vcmax was also similar, A was not changed by elevated ozone. We conclude that gm is an important factor for reduction in Ci-based Vcmax of Siebold’s beech under elevated ozone. 相似文献