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The stem cell niche is a complex unit comprising key components, such as the extracellular matrix and various paracrine factors, which regulate the differentiation of adult stem cells. In our previous study, we established pig spermatogonial stem cells (pSSCs) in culture and identified the expression of insulin-like growth factor binding protein-3 (IGFBP-3) in pSSCs. The present study investigated not only the expression of IGFBP-3, but also its possible role in pSSCs. In this study, IGFBP-3-expressing cells responded positively to protein gene product 9.5 (PGP9.5), which is a marker for pig spermatogonia. IGFBP-3 expression was significantly increased in 60-dayold pig testes. Additionally, the expression levels of insulinlike growth factor I (IGF-I) and its receptor (IGF-IR) were observed in pSSCs and pig Sertoli cells (pSCs). Furthermore, IGF-I treatment enhanced the proliferation of pSCs and pSSCs when they were co-cultured. Blocking the IGF-I pathway using a specific IGF-IR inhibitor dramatically reduced the proliferation of pSCs. In addition, when heparan sulfate was used to sequester IGFBP-3 from IGF-I binding, a significant increase in the proliferation of pSCs was observed. Exogenous IGF-I treatment also increased the expression level of IGFBP-3 in cultured pSSCs. Furthermore, pSSCs grew well in IGF-I-treated pSC conditioned media. In summary, IGF-I and IGF-IR signaling are important for the proliferation of pSCs, and the germ cell-derived IGFBP-3 had an inhibitory effect on the mitotic activity of IGF-I in pSCs.  相似文献   
73.
Tigecycline has in vitro activity against multidrug-resistant and extensively drug-resistant Acinetobacter baumannii (MDR/XDRAB), and may constitute an alternative therapy for treating pneumonia caused by MDR/XDRAB. The aim of this study was to compare the efficacy of tigecycline-based therapy with colistin-based therapy in patients with MDR/XDRAB pneumonia. Between January 2009 and December 2010, patients in the intensive care unit who were diagnosed with MDR/XDRAB pneumonia and treated with either tigecycline or colistin mono-/combination therapy were reviewed. A total of 70 patients were included in our analysis. Among them, 30 patients received tigecycline-based therapy, and 40 patients received colistin-based therapy. Baseline characteristics were similar in the two groups. Clinical success rate was 47% in the tigecycline group and 48% in the colistin group (P = 0.95). There were no differences between the groups with regard to other clinical outcomes, with the exception that nephrotoxicity was observed only in the colistin group (0% vs. 20%; P = 0.009). Clinical and microbiological success rates were numerically higher, and mortality rates were numerically lower in combination therapy group than in the monotherapy group. Multivariate analysis indicated that monotherapy was independently associated with increased clinical failure (aOR, 3.96; 95% CI, 1.03–15.26; P = 0.046). Our results suggest that tigecycline-based therapy was tolerable and the clinical outcome was comparable to that of colistin-based therapy for patients with MDR/XDRAB pneumonia. In addition, combination therapy may be more useful than monotherapy in treatment of MDR/XDRAB pneumonia.  相似文献   
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Park, T.-Y. & Choi, D.K. 2010: Two middle Cambrian diceratocephalid trilobites, Cyclolorenzella convexa and Diceratocephalus cornutus , from Korea: development and functional morphology. Lethaia , Vol. 43, pp. 73–87.
Silicified sclerites of the latest middle Cambrian trilobites, Cyclolorenzella convexa and Diceratocephalus cornutus , have been recovered from the Sesong Formation, Korea. Their morphological similarity and stratigraphic occurrences suggest that D. cornutus is a descendant of C. convexa . The ontogenies of both trilobites demonstrate that a pair of long frontal horns in the cephalon of D. cornutus is an evolutionarily novel structure. It is inferred that redeployment of some pre-existing regulatory gene played a significant role in constructing the frontal horns of D. cornutus . The frontal horns may have been a defensive structure to deter predators. The facial suture of D. cornutus , which extends onto the frontal horns and splits them into the dorsal and ventral halves, was a solution to enable easier forward egression during ecdysis. □ Functional morphology, Korea, Middle Cambrian, ontogeny, trilobites .  相似文献   
75.
ABSTRACT The apoLp-III in the adult hemolymph of Artogeia rapae can associate reversibly with lipophorin. The apoLp-III was purified from the adult and larval hemolymph by KBr density gradient ultracentrifugation, gel permeation chromatography anion exchange chromatography and preparative electrophoresis (Prep Cell). ApoLp-I, ApoLp-II and apoLp-III have the molecular weights of 212 kDa, 80 kDa respectively. N-terminal sequence of apoLp-III were determined. The N-terminal amino acid sequence of apoLp-III shows 50-57% identity with those of other lepidopteran insects. apoLp-III has the antibacterial activity. Injection of bacteria increase the concentration of apoLp-III in the hemolymph, indicating that apoLp-III plays a role in insect immunity. Immunological analysis was also investigated with the anti-apoLp-III.  相似文献   
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This is the first report of occurrence of Vespa velutina Lepeletier from Korea. The diagnosis and taxonomic relationship between geographical subspecies is provided, with a revised key to complement the previous taxonomic information of Korean Vespa species. The ecological aspect of the species is also discussed.  相似文献   
78.
他汀类药物可上调内皮一氧化氮合酶(ENOS)的表达,并由甲羟戊酸(MVA)途径介导,但具体机制未完全阐明.本研究旨在探索洛伐他汀(LVT)上调ENOS表达的分子信号机制并明确同ENOS表达相关的顺式作用元件的定位.洛伐他汀通过减少细胞内固醇,如MVA和geranylgeranyl pyrophosphate (GGPP),从而增加ENOS mRNA的稳定性.因GGPP是细胞内信号蛋白如Ras、Rho GTPase进行翻译后修饰和膜定位所必需的,因此很可能洛伐他汀的作用与细胞内信号途径有关.进一步的实验结果显示Rho激酶抑制剂 hydroxyfasudil和细胞松弛素D均可在转录后水平上调ENOS mRNA表达,表明Rho途径介导的细胞骨架状态在ENOS mRNA降解率的调控中起一定作用. 细胞转染实验证明调控ENOS mRNA 降解的顺式作用元件位于其mRNA序列上的3′未翻译区(3′UTR)和相邻的编码区.其中调控GGPP介导ENOS mRNA稳定性的顺式作用元件位于序列的3 751~4 606位点间;而hydroxyfasudil通过位于3 751~ 4 468位点间的顺式作用元件稳定ENOS mRNA;细胞松弛素D通过位于3 904~4 188位点间的元件稳定ENOS mRNA.洛伐他汀可能通过抑制Rho激酶途径稳定ENOS mRNA,此过程由位于mRNA序列上3′UTR及相邻编码区的多样顺式作用元件介导.另外,细胞骨架的空间构造也可影响ENOS mRNA的稳定性,此过程由位于其mRNA序列编码区的顺式作用元件介导.本研究为转录子稳定性调控机制的进一步研究提供了有力根据,或许可为心血管疾病的治疗提供新的分子靶点.  相似文献   
79.
罗容  吴霞  李静宜  崔湖荣  张楠  张贵君 《生物磁学》2012,(32):6228-6233
目的:研究枳实提取物及其药效组分橙皮苷和新橙皮苷对氧化低密度脂蛋白(oxidized lowd ensity lipoprotein,Ox—LDL)损伤的人脐静脉内皮细胞(human umbilical vein endothelial cells line,HUVEC)细胞间黏附分子-1(intercellular adhesion molecule-1,ICAM-1)表达和一氧化氮(nitric oxide,NO)释放的影响。方法:体外培养HUVEC,50μg/mLOX—LDL制造HUVEC损伤模型。以MTS染色法检测细胞毒性确定用药浓度。细胞ELISA法测定细胞表面ICAM-1的含量,试剂盒测定细胞培养上清液中NO含量。结果:①枳实提取物小于等于2mg/mL时,橙皮苷浓度小于等于0.03125mg/mL时,新橙皮苷浓度小于等于0.25mg/mL时,HUVEC存活率分别大于80%。②2.0mg/mL和1.0mg/mL两个浓度的枳实提取物、15.625μg/mL的橙皮苷和0.2500mg/mL新橙皮苷对OX—LDL诱导的HUVEC的ICAM-1表达有显著抑制作用。③2.0mg/mL枳实提取物显著提高OX—LDL诱导的HUVEC和正常HUVEC培养液中的NO含量;7.813ixg/mL、15.625μg/mL和31.250μg/mL 3个浓度的橙皮苷能显著提高OX—LDL诱导的HUVEC培养液中的NO含量,31.250μg/mL的橙皮苷能促进正常HUVEC的NO释放;0.2500mg/mL和0.1250mg/mL 2个浓度的新橙皮苷能显著提高OX—LDL诱导的HUVEC培养液中的NO含量。结论:枳实提取物及其药效组分橙皮苷、新橙皮苷能抑制Ox-LDL诱导的HUVEC的ICAM-1表达,促进Ox-LDL诱导的HUVEC的NO释放。  相似文献   
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