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21.
Antonis Vlachos Catherine P Raptopoulou Yiannis Sanakis Georgios Diamantopoulos Marina Karayanni Aris Terzis 《Inorganica chimica acta》2004,357(11):3162-3172
Complex [Cr3O(O2CPh)6(MeOH)3](NO3) · 2MeOH (1 · 2MeOH) has been synthesized from the one-pot reaction between Cr(NO3)3 · 9H2O and NaO2CPh in MeOH. The structure of the complex has been solved by single-crystal X-ray crystallography. It crystallizes in the monoclinic space group P21/n with a=14.716(6) Å, b=22.569(8) Å, c=15.755(6) Å, β=95.02(1)°, V=5212.5(4) Å3 and Z=4. Although the cation does not possess any crystallographically imposed symmetry element, its {Cr3(μ3-O)} core is nearly symmetric. Each CrIII…CrIII vector is further bridged by two η1:η1:μ2 benzoates, with a terminal MeOH molecule completing octahedral coordination at each metal ion. The crystal structure consists of layers that are parallel to (0 1 0) crystallographic plane and are formed through π-π stacking interactions and hydrogen bonds. Variable-temperature magnetic susceptibility and solid-state 1H NMR studies indicate that the total spin value of the ground state is 1/2. EPR experiments reveal the existence of a distribution of trimers with axial anisotropy in the g tensor. 相似文献
22.
Alketa Tarushi Catherine P. Raptopoulou Vassilis Psycharis Aris Terzis George Psomas Dimitris P. Kessissoglou 《Bioorganic & medicinal chemistry》2010,18(7):2678-2685
Zinc mononuclear complexes with the second-generation quinolone antibacterial drug enrofloxacin in the absence or presence of a nitrogen donor heterocyclic ligand 1,10-phenanthroline or 2,2′-bipyridine have been synthesized and characterized. Enrofloxacin is on deprotonated mode acting as a bidentate ligand coordinated to zinc ion through the ketone and a carboxylato oxygen atoms. The crystal structure of bis(enrofloxacinato)(1,10-phenanthroline)zinc(II), 2, has been determined by X-ray crystallography. The biological activity of the complexes has been evaluated by examining their ability to bind to calf-thymus DNA (CT DNA) with UV and fluorescence spectroscopies. UV studies of the interaction of the complexes with DNA have shown that they can bind to CT DNA and the DNA binding constants have been calculated. Competitive studies with ethidium bromide (EB) have shown that the complexes exhibit the ability to displace the DNA-bound EB indicating that they bind to DNA in strong competition with EB for the intercalative binding site. The complexes exhibit good binding propensity to human and bovine serum albumin proteins having relatively high binding constant values. 相似文献
23.
KD Henley KA Gooding AN Economides M Gannon 《American journal of physiology. Endocrinology and metabolism》2012,303(6):E752-E761
Current endeavors in the type 2 diabetes (T2D) field include gaining a better understanding of extracellular signaling pathways that regulate pancreatic islet function. Recent data suggest that both Bmp and Wnt pathways are operative in pancreatic islets and play a positive role in insulin secretion and glucose homeostasis. Our laboratory found the dual Bmp and Wnt antagonist Sostdc1 to be upregulated in a mouse model of islet dysmorphogenesis and nonimmune-mediated lean diabetes. Because Bmp signaling has been proposed to enhance β-cell function, we evaluated the role of Sostdc1 in adult islet function using animals in which Sostdc1 was globally deleted. While Sostdc1-null animals exhibited no pancreas development phenotype, a subset of mutants exhibited enhanced insulin secretion and improved glucose homeostasis compared with control animals after 12-wk exposure to high-fat diet. Loss of Sostdc1 in the setting of metabolic stress results in altered expression of Bmp-responsive genes in islets but did not affect expression of Wnt target genes, suggesting that Sostdc1 primarily regulates the Bmp pathway in the murine pancreas. Furthermore, our data indicate that removal of Sostdc1 enhances the downregulation of the closely related Bmp inhibitors Ctgf and Gremlin in islets after 8-wk exposure to high-fat diet. These data imply that Sostdc1 regulates expression of these inhibitors and provide a means by which Sostdc1-null animals show enhanced insulin secretion and glucose homeostasis. Our studies provide insights into Bmp pathway regulation in the endocrine pancreas and reveal new avenues for improving β-cell function under metabolic stress. 相似文献
24.
Rijken MJ Papageorghiou AT Thiptharakun S Kiricharoen S Dwell SL Wiladphaingern J Pimanpanarak M Kennedy SH Nosten F McGready R 《PloS one》2012,7(2):e31411
Background
Intermittent preventive treatment (IPT), the main strategy to prevent malaria and reduce anaemia and low birthweight, focuses on the second half of pregnancy. However, intrauterine growth restriction may occur earlier in pregnancy. The aim of this study was to measure the effects of malaria in the first half of pregnancy by comparing the fetal biparietal diameter (BPD) of infected and uninfected women whose pregnancies had been accurately dated by crown rump length (CRL) before 14 weeks of gestation.Methodology/Principal Findings
In 3,779 women living on the Thai-Myanmar border who delivered a normal singleton live born baby between 2001–10 and who had gestational age estimated by CRL measurement <14 weeks, the observed and expected BPD z-scores (<24 weeks) in pregnancies that were (n = 336) and were not (n = 3,443) complicated by malaria between the two scans were compared. The mean (standard deviation) fetal BPD z-scores in women with Plasmodium (P) falciparum and/or P.vivax malaria infections were significantly lower than in non-infected pregnancies; −0.57 (1.13) versus −0.10 (1.17), p<0.001. Even a single or an asymptomatic malaria episode resulted in a significantly lower z-score. Fetal female sex (p<0.001) and low body mass index (p = 0.01) were also independently associated with a smaller BPD in multivariate analysis.Conclusions/Significance
Despite early treatment in all positive women, one or more (a)symptomatic P.falciparum or P.vivax malaria infections in the first half of pregnancy result in a smaller than expected mid-trimester fetal head diameter. Strategies to prevent malaria in pregnancy should include early pregnancy. 相似文献25.
Kentaro Suzuki Yasuha Adachi Tomokazu Numata Shoko Nakada Motoko Yanagita Naomi Nakagata Sylvia M. Evans Daniel Graf Aris Economides Ryuma Haraguchi Anne M. Moon Gen Yamada 《PloS one》2012,7(9)
Sirenomelia, also known as mermaid syndrome, is a developmental malformation of the caudal body characterized by leg fusion and associated anomalies of pelvic/urogenital organs including bladder, kidney, rectum and external genitalia. Most affected infants are stillborn, and the few born alive rarely survive beyond the neonatal period. Despite the many clinical studies of sirenomelia in humans, little is known about the pathogenic developmental mechanisms that cause the complex array of phenotypes observed. Here, we provide new evidences that reduced BMP (Bone Morphogenetic Protein) signaling disrupts caudal body formation in mice and phenocopies sirenomelia. Bmp4 is strongly expressed in the developing caudal body structures including the peri-cloacal region and hindlimb field. In order to address the function of Bmp4 in caudal body formation, we utilized a conditional Bmp4 mouse allele (Bmp4flox/flox) and the Isl1 (Islet1)-Cre mouse line. Isl1-Cre is expressed in the peri-cloacal region and the developing hindimb field. Isl1Cre;Bmp4flox/flox conditional mutant mice displayed sirenomelia phenotypes including hindlimb fusion and pelvic/urogenital organ dysgenesis. Genetic lineage analyses indicate that Isl1-expressing cells contribute to both the aPCM (anterior Peri-Cloacal Mesenchyme) and the hindlimb bud. We show Bmp4 is essential for the aPCM formation independently with Shh signaling. Furthermore, we show Bmp4 is a major BMP ligand for caudal body formation as shown by compound genetic analyses of Bmp4 and Bmp7. Taken together, this study reveals coordinated development of caudal body structures including pelvic/urogenital organs and hindlimb orchestrated by BMP signaling in Isl1-expressing cells. Our study offers new insights into the pathogenesis of sirenomelia. 相似文献
26.
27.
Thomas Ant Martha Koukidou Polychronis Rempoulakis Hong-Fei Gong Aris Economopoulos John Vontas Luke Alphey 《BMC biology》2012,10(1):1-8
Ubiquitin signaling pathways rely on E3 ligases for effecting the final transfer of ubiquitin from E2 ubiquitin conjugating enzymes to a protein target. Here we re-evaluate the hybrid RING/HECT mechanism used by the E3 family RING-between-RINGs (RBRs) to transfer ubiquitin to substrates. We place RBRs into the context of current knowledge of HECT and RING E3s. Although not as abundant as the other types of E3s (there are only slightly more than a dozen RBR E3s in the human genome), RBRs are conserved in all eukaryotes and play important roles in biology. Re-evaluation of RBR ligases as RING/HECT E3s provokes new questions and challenges the field. 相似文献
28.
29.
Grammatikopoulos George Drilias Periklis Kyparissis Aris Petropoulou Yiola Manetas Yiannis 《Plant Ecology》2001,154(1-2):117-122
The effects of sub-ambient levels of UV-B radiation on the shrub Rosmarinus officinalis L. were investigated in a field filtration experiment in which the ambient UV-B was manipulated by a combination of UV-B transmitting and UV-B absorbing filters. As a result, the plants were receiving near-ambient or drastically reduced UV-B radiation doses. Drastic reduction of UV-B radiation had no effect on mean, total and maximum stem length, number of stems per plant, dry mass of leaves, stems and roots and leaf nitrogen and phenolic contents. However, flowering was more pronounced under reduced UV-B radiation during the winter period which coincides with ascending ambient UV-B radiation. In contrast, during autumn and early winter, a period which coincides with descending ambient UV-B radiation, flowering was unaffected by reduced UV-B radiation. We can conclude that natural UV-B radiation does not affect growth of Rosmarinus officinalis, but its reduction could influence the flowering pattern of the species. 相似文献
30.
A mathematical model for traveling bands of motile and chemotactic bacteria in the presence of cell growth and death is examined.
It is found that asymptotic traveling wave solutions exist in the absence of chemotaxis, due to the balance of growth, death
and random motility. Thus random motility confers the ecological advantage of population propagation through migration into
nutrient-rich regions. The presence of chemotaxis amplifies this advantage by moving more cells into higher nutrient concentration
regions, resulting in larger and faster bands. Therefore there seem to be two types of traveling bands that can be attained
by chemotactic bacteria in the presence of growth and death: (1) these growth/death/motility bands; and (2) pure chemotactic
‘Keller-Segel'-type bands. Comparison to experimental observations by Chapman in 1973 indicate that the latter seem to be
formed. The relationship between these two types of solution is at present uncertain. The growth/death/motility bands may
have relevance on longer time or distance scales characteristic of microbial ecological systems. 相似文献