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31.
K. Nagashima M. Ando 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1994,164(1):47-54
To characterize mechanisms of esophageal desalination, osmotic water permeability and ion fluxes were measured in the isolated esophagus of the seawater eel. The osmotic permeability coefficient in the seawater eel esophagus was 2·10-4 cm·s-1. This value was much lower than those in tight epithelial, although the eel esophagus is a leaky epithelium with a tissue resistance of 77 ohm·cm-2. When the esophagus was bathed in normal Ringer solutions on both sides no net ion and water fluxes were observed. However, when mucosal NaCl concentration was increased by a factor of 3, Na+ und Cl- ions were transferred from mucosa to serosa (desalination). If only Na+ or Cl- concentration in the mucosal fluid was increased by a factor of 3, net Na+ and Cl- fluxes were reduced to 30–40%, indicating that 60–70% of the net Na+ and Cl- fluxes are coupled mutually. The coupled NaCl transport seems to be effective in desalting the luminal high NaCl. The remaining 30–40% of the total Na+ and Cl- fluxes seems to be due to a simple diffusion, because these components are independent of each other and follow their electrochemical gradients, and also because these fluxes remain even after treatment with NaCN or ouabain. A half of the coupled NaCl transport could be explained by a Na+/H+–Cl-/HCO
3
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double exchanger on the apical membrane of the esophageal epithelium, because mucosal amiloride and 4.4-diisothiocyanatostilbene-2,2-disulphonic acid inhibited the net Na+ and Cl- fluxes by approximately 30%. The other half of the coupled NaCl transport, which follows their electrochemical gradients, still remains to be explained.Abbreviations DIDS
4,4-diisothiocyanatostilbene-2,2-disulphonic acid
- NMDG
N-methyl-d-glucosamine
-
P
Cl
Cl- permeability coefficient
- PD
transepithelial potential difference
-
P
Na
Na+ permeability coefficient
-
P
osm
osinotic permeability coefficient
- TALH
thick ascending limb of Henle's loop 相似文献
32.
We compared the granuloma morphology and immune response of hamsters inoculated withParacoccidioides brasiliensis (Pb) into the cheek pouch, which lacks lymphatic drainage, and into the footpad, which is rich in lymphatics. Our objective was to better understand the modulation ofPb granuloma in an immunocompetent animal inoculated in an immunologically privileged site. The humoral immune response (ELISA) and cell mediated immunity (footpad test) became positive on days 7 and 14, respectively in animals inoculated into footpad and on days 35 and 60 in animals inoculated into the pouch. Typical epithelioid granulomas were observed at both sites on day 14. The number of fungi gradually decreased from the beginning of the experiment in footpad lesions, but only after day 35 in pouch granulomas, when cell mediated immunity was detectable. The results indicate that typical epithelioid paracoccidioidomycotic granulomas may develop in the absence of a detectable immune response; however, they are incapable of controlling fungal reproduction. Lack of lymphatic drainage delays the appearance of a detectable immune response, but with time fungi escape from the pouch, elicit an immune response and reach other organs. Our results further indicate the importance of the lymphatics in the pathogenesis of paracoccidioidomycosis.Abbreviations HCP
hamster cheek pouch
-
Pb
Paracoccidioides brasiliensis
- Pbmycosis
Paracoccidioidomycosis 相似文献
33.
34.
Long-chain fatty acids in germination-inhibiting animal-wastecomposts were identified by gas chromatography-mass spectrometryas myristic, palmitic, stearic, oleic, linoleic, and linolenicacids. These acids were found at concentrations greater than0.25 mg (g dry compost)1. The identified acids, togetherwith lauric acid, and five kinds of short- and medium-chainfatty acid, were tested for their effects on the germinationprocess of sorghum seeds. The authentic long-chain fatty acids, which were dissolved ina 1:9 (v/v) mixture of methanol and distilled water at 40 mgliter1, significantly reduced the -amylase activity,physiological water uptake, and ATP content of the germinatingseeds during the first 24h of imbibition, as well as the rateof germination of seeds. Among the tested fatty acids, myristicand palmitic acids were the most potent inhibitors of germination.The inhibitory effects of long-chain fatty acids were strongerthan those of the phenolic acids. The short- and medium-chainfatty acids did not have any significant germination-inhibitoryeffects at 40 mg liter1. The results indicate that thelong-chain fatty acids are the dominant inhibitors of germinationin animal-waste composts, and that the inhibition of the -amylaseactivity in germinating sorghum seeds is one aspect of the modeof action of these long-chain fatty acids.
1On leave from the Department of Crop Science, Faculty of Agriculture,University of Peradeniya, Sri Lanka. 相似文献
35.
36.
Kazunori Yokoi Yoshiaki Yasumizu Naganari Ohkura Koei Shinzawa Daisuke Okuzaki Nene Shimoda Hideya Ando Nanako Yamada Manabu Fujimoto Atsushi Tanemura 《Pigment cell & melanoma research》2023,36(5):355-364
Vitiligo is a common depigmentation disorder characterized by the selective loss of melanocytes. In our daily clinic experience, we noticed that the skin tightness of hypopigmented lesions would be more evident in comparison to that of uninvolved perilesional skin in vitiligo patients. Therefore, we hypothesized that collagen homeostasis might be maintained in vitiligo lesions, irrespective of the substantial excessive oxidative stress that occurs in association with the disease. We found that the expression levels of collagen-related genes and anti-oxidative enzymes were upregulated in vitiligo-derived fibroblasts. Abundant collagenous fibers were observed in the papillary dermis of vitiligo lesions in comparison to uninvolved perilesional skin by electron microscopy. The production of matrix metalloproteinases that degraded collagen fibers was suppressed. The deposition of acrolein adduct protein, which is a product of oxidative stress, was significantly reduced in vitiligo dermis and fibroblasts. As part of the mechanism, we found upregulation of the NRF2 signaling pathway activity, which is an important defense system against oxidative stress. Taken together, we demonstrated that the anti-oxidative action and collagen production were upregulated and that the collagen degeneration was attenuated in vitiligo dermis. These new findings may provide important clues for the maintenance of antioxidant ability in vitiligo lesions. 相似文献
37.
38.
Petunia guarapuavensis (Solanaceae): A new species from planalto of Paraná and Santa Catarina,Brazil
Petunia guarapuavensis, a new species fromplanalto (high plateau) of Paraná and Santa Catarina in Brazil, is described, and its morphological distinction from related species, features of the habitats, and geographical distribution are discussed. 相似文献
39.
Shigeru Ando 《Ecological Research》1995,10(3):321-325
Body temperatures of 11 bird species, including cuckoos, were measured in an artificial meteorological room. Ratios of change
in body temperature to that in air temperature were thereby obtained for each species. Cuckoos demonstrate a remarkably high
value, indicating a particularly low ability to regulate body temperature. Viewed in this light, the cuckoo's parasitic behavior
is very likely an adaptation to overcome a physiological disadvantage. This in turn might be expected to reinforce delay in
evolution of temperature homeostasis. 相似文献
40.
Fungitoxic phenolic compounds were released from cucumber mosaic virus (CMV)-infected and noninfected cowpea protoplasts. These compounds were presumed by thin layer chromatography as similar compounds released into the leaf ambient fluids when CMV-infected cowpea leaves were incubated in water. Larger amounts of the compounds were released from CMV-infected cowpea protoplasts than from noninfected protoplasts. 相似文献