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41.
Ye Suji Jeong Deokyeol Shon Jong Cheol Liu Kwang-Hyeon Kim Kyoung Heon Shin Minhye Kim Soo Rin 《Journal of industrial microbiology & biotechnology》2019,46(12):1725-1731
Journal of Industrial Microbiology & Biotechnology - Pentose sugars are increasingly being used in industrial applications of Saccharomyces cerevisiae. Although l-arabinose is a highlighted... 相似文献
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Kim JH Kim JH Ahn BJ Park JH Shon HK Yu YS Moon DW Lee TG Kim KW 《Biophysical journal》2008,94(10):4095-4102
The distribution and movement of elemental ions in biologic tissues is critical for many cellular processes. In contrast to chemical techniques for imaging the intracellular distribution of ions, however, techniques for imaging the distribution of ions across tissues are not well developed. We used time-of-flight secondary ion mass spectrometry (TOF-SIMS) to obtain nonlabeled high-resolution analytic images of ion distribution in ischemic retinal tissues. Marked changes in Ca2+ distribution, compared with other fundamental ions, such as Na+, K+, and Mg2+, were detected during the progression of ischemia. Furthermore, the Ca2+ redistribution pattern correlated closely with TUNEL-positive (positive for terminal deoxynucleotidyl transferase-mediated 2′-deoxyuridine 5′-triphosphate nick end-labeling) cell death in ischemic retinas. After treatment with a calcium chelator, Ca2+ ion redistribution was delayed, resulting in a decrease in TUNEL-positive cells. These results indicate that ischemia-induced Ca2+ redistribution within retinal tissues is associated with the order of apoptotic cell death, which possibly explains the different susceptibility of various types of retinal cells to ischemia. Thus, the TOF-SIMS technique provides a tool for the study of intercellular communication by Ca2+ ion movement. 相似文献
44.
What are the dynamics and regularities underlying social contact, and how can contact with the people in one''s social network be predicted? In order to characterize distributional and temporal patterns underlying contact probability, we asked 40 participants to keep a diary of their social contacts for 100 consecutive days. Using a memory framework previously used to study environmental regularities, we predicted that the probability of future contact would follow in systematic ways from the frequency, recency, and spacing of previous contact. The distribution of contact probability across the members of a person''s social network was highly skewed, following an exponential function. As predicted, it emerged that future contact scaled linearly with frequency of past contact, proportionally to a power function with recency of past contact, and differentially according to the spacing of past contact. These relations emerged across different contact media and irrespective of whether the participant initiated or received contact. We discuss how the identification of these regularities might inspire more realistic analyses of behavior in social networks (e.g., attitude formation, cooperation). 相似文献
45.
P. J. Russell J. Plomley I. Ho Shon H. O’Grady N. Pearce 《Cell biochemistry and biophysics》1993,22(1-3):27-47
Local administration of radioimmunoconjugates may allow successful tumor therapy. Bladder cancer appears well suited to this approach, because of its superficial and multifocal nature, and because it will allow direct intravesical administration of conjugates. Implantation of human bladder cancer cell lines in the bladder wall of nude rats results in tumor formation, providing an excellent model to test this. We have developed two murine monoclonal antibodies (MAbs), BLCA-8, IgG3, and BLCA-38, IgG1, both of which react with malignant cells and shed into voided urine of patients with transitional cell carcinoma (TCC) of the bladder, but not with normal bladder urothelial cells. Radioimmunoconjugates produced with131Iodine (131I) or125I have been used for biodistribution studies following administration directly into the bladder. Radioiodinated intact MAbs or Fabs administered intravesically into nontumor-bearing rats did not leak into the systemic circulation and were stable in urine for up to 100h. Biodistribution studies carried out following intraperitoneal or intravesical administration of radioimmunoconjugates to tumor-bearing nude rats indicate good tumor uptake of both MAbs. Together with immunoreactivity assays, these studies demonstrate that131I-labeled MAbs have considerable potential for intravesical radioimmunotherapy of human bladder tumors, and further studies are under way. 相似文献
46.
The retinoblastoma susceptibility gene product undergoes cell cycle-dependent dephosphorylation and binding to and release from SV40 large T 总被引:64,自引:0,他引:64
Synchronized monkey cells pulse-labeled with [35S]-methionine and chased for various lengths of time were extracted, and immunoprecipitations were performed using monoclonal antibodies directed against the retinoblastoma protein (RB) and SV40 T antigen (T). By following a discrete population of these two proteins through the cell cycle, the following information was obtained. RB, which is wholly unphosphorylated in G1, became phosphorylated at the beginning of S and remained phosphorylated through S and G2. RB was, then, completely dephosphorylated between the end of G2 and the beginning of G1. Second, while all of the detectable unphosphorylated RB can be found complexed with T, these complexes present during G1 dissociated in S and reformed again in M or early G1. Finally, T molecules appeared to oligomerize prior to binding RB. Thus, complex formation between T and RB may be regulated in part by the cell cycle-dependent phosphorylation and dephosphorylation of RB and by the quaternary structure of T. 相似文献
47.
A.Martin M. Zade-Oppen James M. Schooler Paul Cook Daniel C. Tosteson 《生物化学与生物物理学报:生物膜》1979,555(2):285-298
Ouabain-sensitive Na+ and K+ fluxes and ATP content were determined in high potassium sheep erythrocytes at different values of membrane potential and internal pH. Membrane potential was adjusted by suspending erythrocytes in media containing different concentrations of MgCl2 and sucrose. Concomitantly either the external pH was changed sufficiently to maintain a constant internal pH or the external pH was kept constant with a resultant change of internal pH. The erythrocytes were preincubated before the flux experiment started in a medium which produced increased ATP content in order to avoid substrate limitation of the pump. p] It was found that an increased cellular pH reduced the rates of active transport of Na+ and K+ without significantly altering the ratio of pumped . This reduction was not due to limitation in the supply of ATP although ATP content decreased when internal pH increased. Changes of membrane potential in the range between ?10 and +60 mV at constant internal pH did not affect the rates of active transport of Na+ or K+. 相似文献
48.
Abstract The risk of non-target effects from biological control agents can be reduced if we can better identify effective agents prior to release. Introducing only those agents with high potential for effective control will reduce the number of agents released and reduce the probability of both direct and indirect non-target impacts. Identifying effective agents requires understanding the roles that resources, disturbances and herbivory play in regulating plant populations under natural field conditions. Here we propose a series of experiments that will contrast the mechanisms of population regulation of two invasive wetland plants, alligator weed ( Alternanthera philoxeroides ) and lippia ( Phyla canescens ), with native congener species, Alternanthera denticulata and Phyla nodiflora . We hypothesise that the native plants will have greater growth rates when nutrients are low and herbivores are present, whereas the introduced plants will exhibit greater growth rates when nutrients are high and herbivores are absent. 相似文献
49.
Abstract Cabomba caroliniana is a submerged aquatic plant from South America that is becoming a serious weed worldwide. It spreads by seed and by fragmentation and has an extremely wide climatic range, invading lakes and ponds from tropical (Darwin, Australia: latitude 12°) to cold temperate regions (Peterborough, Canada: latitude 45°). There are currently no effective methods of managing cabomba infestations and funding has been allocated to research biological methods. Surveys have examined cabomba in its native range and have identified several potential biological control agents. The most promising are a stem boring weevil ( Hydrotimetes natans ) and an aquatic moth ( Paracles spp.). Here we predict the change in cabomba populations after the introduction of the biological control agents. Our predictions are based on quantitative surveys of cabomba populations at three lakes in south-east Queensland, qualitative observations of cabomba in its native range, and conceptual knowledge of how the realised niche of cabomba might be affected by herbivore damage. 相似文献
50.