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951.
Tanaka K Endo S Imanaka T Shizuma K Hasai H Hoshi M 《Radiation and environmental biophysics》2008,47(3):323-330
Epilation was reported among atomic bomb survivors in Hiroshima and Nagasaki, including "early entrance survivors" who entered the cities after the bombings. The absorbed dose to the skin by neutron-activated soil via beta and gamma rays has been estimated in a preliminary fashion, for these survivors in Hiroshima. Estimation was done for external exposures from activated soil on the ground as well as skin and hair contamination from activated soil particles, using the Monte Carlo radiation transport code MCNP-4C. Assuming 26 mum thickness of activated soil on the skin as an example, the skin dose was estimated to be about 0.8 Gy, for an exposure scenario that includes the first 7 days after the bombing at 1 m above the ground at the hypocenter. In this case, 99% of the total skin dose came from activated radionuclides in the soil, i.e., 0.19 and 0.63 Gy due to beta and gamma rays, respectively. In contrast, contribution to skin dose due to skin contamination with soil particles was found to be about 1%. To make it comparable to the exposure by neutron-activated soil on the ground, a soil thickness on the skin of about 1 mm would be required, which seems to be difficult to keep for a long time. Fifty-five percent of the 7-day skin dose was delivered during the first hour after the bombing. Our estimates of the skin dose are lower than the conventionally reported threshold of 2 Gy for epilation. It should be noted, however, that the possibility of more extreme exposure scenarios for example for entrants who received much heavier soil contamination on their skin cannot be excluded. 相似文献
952.
Effect of [6]-gingerol, a major pungent component in ginger, on the proliferation of a rat ascites hepatoma AH109A cells was
investigated by measuring [3H]thymidine incorporation into acid-insoluble fraction of the cultured cells and that on the invasion by co-culturing the
hepatoma cells with rat mesentery-derived mesothelial cells. [6]-Gingerol inhibited both the proliferation and invasion of
hepatoma cells in a dose-dependent manner at concentrations of 6.25–200 μM (proliferation) and 50–200 μM (invasion). [6]-Gingerol
accumulated cells in S phase and elongated doubling time of hepatoma cells, and increased the rate of apoptosis. Hepatoma
cells previously cultured with hypoxanthine (HX) and xanthine oxidase (XO) or with hydrogen peroxide showed increased invasive
activities. [6]-Gingerol suppressed the reactive oxygen species-potentiated invasive capacity by simultaneously treating AH109A
cells with [6]-gingerol, HX and XO or with [6]-gingerol and hydrogen peroxide. Furthermore, [6]-gingerol reduced the intracellular
peroxide levels in AH109A cells. These results suggest that the suppression of hepatoma cell proliferation by [6]-gingerol
may be due to cell cycle arrest and apoptosis induction. They also suggest that the anti-oxidative property of [6]-gingerol
may be involved in its anti-invasive activity of hepatoma cells. 相似文献
953.
Yasuda S Hasui S Kobayashi M Itagaki S Hirano T Iseki K 《Bioscience, biotechnology, and biochemistry》2008,72(2):329-334
The aim of this study was to elucidate the mechanism of folate transport in the placenta. A study of folate was carried out to determine which carriers transport folates in the human choriocarcinoma cell line BeWo, a model cell line for the placenta. We investigated the effects of buffer pH and various compounds on folate uptake. In the first part of the study, the expression levels of the mRNA of the folate receptor alpha (FRalpha), the reduced folate carrier (RFC), and heme carrier protein 1 (HCP1) were determined in BeWo cells by RT-PCR analysis. Folate uptake into BeWo cells was greater under an acidic buffer condition than under a neutral one. Structure analogs of folates inhibited folate uptake under all buffer pH conditions, but anion drugs (e.g., pravastatin) inhibited folate uptake only under an acidic buffer condition. Although thiamine pyrophosphate (TPP), a substrate of RFC, had no effect on folate uptake, hemin (a weak inhibitor of folate uptake via HCP1) decreased folate uptake to about 80% of the control level under an acidic buffer condition. Furthermore, kinetic analysis showed that hemin inhibited the low-affinity phase of folate uptake under an acidic buffer condition. We conclude that pH-dependent folate uptake in BeWo cells is mediated by at least two carriers. RFC is not involved in folate uptake, but FRalpha (high affinity phase) and HCP1 (low affinity phase) transport folate in BeWo cells. 相似文献
954.
Periodontal disease, for which smoking is a known risk factor, is infectious, and is associated with oral biofilm. Cytokines mediate and regulate immune and inflammatory responses. Lipopolysaccharide produced by periodontopathic bacteria plays a role in the progression of periodontitis. The effect of nicotine on cytokine production in mice was evaluated in this study. Nicotine (10 or 200 microg mouse(-1)) was administered intraperitoneally to 4-week-old female BALB/c mice, once a day, for 49 days. Control mice received injections of phosphate-buffered saline. Blood was collected from all mice and serum IL-6, IL-10, tumor necrosis factor (TNF)-alpha and IFN-gamma levels were measured by an enzyme-linked immunosorbent assay on the 42nd day. IL-6, IL-10 and IFN-gamma levels in the nicotine-treated mice were higher than those in the control mice. However, no differences were found in TNF-alpha levels between nicotine-treated and control mice. Lipopolysaccharide (20 microg mouse(-1)) purified from Aggregatibacter actinomycetemcomitans (formerly Actinobacillus actinomycetemcomitans) Y4 was administered intraperitoneally on the 49th day. A rapid increase in TNF-alpha was observed in the control mice at 2 h after administration of lipopolysaccharide. In contrast, no increase was noted in the nicotine-treated groups. Significantly higher levels of IFN-gamma were seen in the 200 microg nicotine-treated mice at 2 h after administration of lipopolysaccharide (P<0.05). The results showed that cytokine levels were influenced by nicotine in mice. 相似文献
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958.
Anura Pushpakumara Rathnayake Hirofumi Kadono Satoru Toyooka Makoto Miwa 《Environmental and Experimental Botany》2008,64(3):314-321
This study presents a new technique to measure root elongation of Japanese red pine (Pinus densiflora Seibold & Zucc.) seedlings with very high sensitivity in the order of sub-nanometer by using a novel optical interference method called statistical interferometry. The principle of the statistical interferometry is based on the statistics of a speckle field, which is generated when a rough surface is illuminated by a laser light. The technique facilitates to obtain minute root elongation measurements in the order of sub-seconds. The root elongation behavior of Pinus densiflora seedlings infected with ectomycorrhizal fungi, Pisolithus sp. (Ps) and Cenococcum geophilum Fr. (Cg), was investigated in comparison with that of an uninfected control. In the experiments, two points on a root with the separation of 3 mm were illuminated by laser beams and the elongation was measured continuously by analyzing speckle patterns successively taken by a CCD camera. The root elongation rate (RER), measured as the length of root elongation per second per millimeter (mean ± S.D.) for Ps-infected, Cg-infected and uninfected seedlings were 10.85 ± 2.41, 5.54 ± 1.43, and 2.41 ± 1.01 nm s?1 mm?1, respectively. We found that the RERs of seedlings infected with ectomycorrhizal fungi were significantly higher than that of the uninfected seedlings, and the seedlings infected with Ps fungi showed the highest RER. We conducted another experiment to observe two-dimensional root growth, in which the growth measurements were obtained for 4 months. From this experiment, we observed that root growth of ectomycorrhizal fungi infected seedlings were higher than that of the uninfected seedlings. The evaluation of results from these two techniques proves that the proposed statistical interferometry is much faster and very sensitive technique, where the time required for growth monitoring is 107 times less than the other. We can conclude that, at the scale of either very short time or relatively long time, the symbiotic relationship between root and ectomycorrhiza has a positive effect steadily on the root elongation. 相似文献
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960.
Toshiyuki Fukada Natacha Civic Tatsuya Furuichi Shinji Shimoda Kenji Mishima Hiroyuki Higashiyama Yayoi Idaira Yoshinobu Asada Hiroshi Kitamura Satoru Yamasaki Shintaro Hojyo Manabu Nakayama Osamu Ohara Haruhiko Koseki Heloisa G. dos Santos Luisa Bonafe Russia Ha-Vinh Andreas Zankl Sheila Unger Marius E. Kraenzlin Jacques S. Beckmann Ichiro Saito Carlo Rivolta Shiro Ikegawa Andrea Superti-Furga Toshio Hirano 《PloS one》2008,3(11)