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91.
There has been a close association between Yale University and educational institutions in China for almost 80 years. Although this relationship was interrupted during the early years of the People''s Republic of China, collaboration between Yale and medical institutions in China is in the process of being resumed. The history of this collaboration and the opening phases of its resumption are described. 相似文献
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Fluorescence studies of the accessibility of the 3'' ends of the ribosomal RNAs in Escherichia coli ribosomes and subunits. 总被引:3,自引:3,他引:0 下载免费PDF全文
The accessibility of the 3'-ends of E. coli in various states has been probed by reaction, after periodate oxidation, with the fluorescent dye proflavine semicarbazide. Free oxidized 16S and 23S rRNAs each react with 2 equivalents of dye. The 23S rRNA is equally reactive in the 50S subunit and the 70S ribosome. The 16S RRNA 3'-end is accessible in the 30S subunit. In the intact 70S particle, periodate can reach the 3'-end of the 16S rRNA but the dye cannot. The 5S rRNA is relatively inaccessible to periodate oxidation or dye reaction in the 70S particle. Dye-labelled 16S rRNA will reconstitute into 30S particles but they are inactive in polypeptide synthesis. This is apparently due to the inability of the 30S particles to form tight complexes with 50S subunits. Iodide quenching studies indicate that the environment of the 3'-end of 16S rRNA in the 30S particle is different from that of the free rRNA. 相似文献
94.
Hsiung HM Smiley DL Zhang XY Zhang L Yan LZ Craft L Heiman ML Smith DP 《Peptides》2005,26(10):1988-1996
Human beta-MSH(1-22) was first isolated from human pituitary as a 22-amino acid (aa) peptide derived from a precursor protein, pro-opiomelanocortin (POMC). However, Bertagna et al. demonstrated that a shorter human beta-MSH(5-22), (DEGPYRMEHFRWGSPPKD), is a true endogenous peptide produced in human hypothalamus. In this report, we demonstrated that in vitro enzymatic cleavage of native human beta-MSH(5-22) with two ubiquitous dipeptidyl peptidases (DPP), DPP-I and DPP-IV, generated two potent MC3/4R peptide analogues, beta-MSH(7-22) (GPYRMEHFRWGSPPKD) and beta-MSH(9-22) (YRMEHFRWGSPPKD). In fact, the MC4R binding affinity and functional potency of beta-MSH(7-22) (Ki=4.6 nM, EC50=0.6 nM) and beta-MSH(9-22) (Ki=5.7 nM, EC50=0.6 nM) are almost an order of magnitude greater than those of their parent peptide, beta-MSH(5-22) (MC4R, Ki=23 nM, EC50= 3nM). Furthermore, the DPP-I/DPP-IV cleaved peptide, beta-MSH(9-22), when administered intracerebroventricularly (ICV) at a dose of 3 nmol/rat, potently induced an acute negative energy balance in a diet-induced obese rat model, while its parent molecule, beta-MSH(5-22), administered at the same dose did not have any effect. These data suggest that DPP-I and DPP-IV may play a role in converting the endogenous beta-MSH(5-22) to more potent peptides that regulate energy homeostasis in the hypothalamus. 相似文献
95.
Adlersberg M Hsiung SC Glickstein SB Liu KP Tamir H Schmauss C 《Journal of neurochemistry》2004,90(4):865-873
Mice lacking dopamine D2 receptors exhibit a significantly decreased agonist-promoted forebrain neocortical D1 receptor activation that occurs without changes in D1 receptor expression levels. This raises the possibility that, in brains of D2 mutants, a substantial portion of D1 receptors are uncoupled from their G protein, a phenomenon known as receptor desensitization. To test this, we examined D1-agonist-stimulated [35S]GTPgammaS binding (in the presence and absence of protein phosphatase inhibitors) and cAMP production (in the presence and absence of pertussis toxin) in forebrain neocortical tissues of wild-type mice and D2-receptor mutants. These studies revealed a decreased agonist-stimulated G-protein activation in D2 mutants. Moreover, whereas protein phosphatase 1/2A (PP1/2A) and 2B (PP2B) inhibitors decrease [35S]GTPgammaS binding in a concentration-dependent manner in wild type, they have either no (PP2B) or only partial (PP1/2A) effects in D2 mutants. Furthermore, for D2 mutants, immunoprecipitation experiments revealed increased basal and D1-agonist-stimulated phosphorylation of D1-receptor proteins at serine residues. Finally, D1 immunoprecipitates of both wild type and D2 mutants also contain protein kinase A (PKA) and PP2B immunoreactivities. In D2 mutants, however, the catalytic activity of the immunoprecipitated PP2B is abolished. These data indicate that neocortical D1 receptors are physically linked to PKA and PP2B and that the increased phosphorylation of D1 receptors in brains of D2 mutants is due to defective dephosphorylation of the receptor rather than increased kinase-mediated phosphorylation. 相似文献
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COMPARISON OF THE AGAR OVERLAY TECHNIQUE WITH THE FLUID CULTURE TECHNIQUE FOR ISOLATION AND IDENTIFICATION OF ENTEROVIRUSES SHOWED THE FORMER TO BE USEFUL: (i) for isolation of enterovirus when the number of virus particles was too small to produce detectable cytopathic effect (CPE) in fluid cultures, (ii) for isolation of echovirus 22 which did not produce detectable CPE in fluid cultures, (iii) as an aid to rapid differentiation of enteroviruses, and (iv) for differentiation of viruses in mixed infections. Nonpolio enterovirus isolation experience in the New Haven area over a 4-year period is presented. It was concluded that the agar overlay technique is both useful and relatively simple for routine examination of clinical specimens in a diagnostic laboratory. 相似文献
99.
Heat shock protein 70 and AMP‐activated protein kinase contribute to 17‐DMAG‐dependent protection against heat stroke 下载免费PDF全文
Yi‐Jen Peng Yen‐Mei Lee Chung‐Yu Yang Yi‐Ju Tsai Mao‐Hsiung Yen Pao‐Yun Cheng 《Journal of cellular and molecular medicine》2016,20(10):1889-1897
Heat shock protein 70 (Hsp70) preconditioning induces thermotolerance, and adenosine monophosphate (AMP)‐activated protein kinase (AMPK) plays a role in the process of autophagy. Here, we investigated whether 17‐dimethylaminoethylamino‐17‐demethoxy‐geldanamycin (17‐DMAG) protected against heat stroke (HS) in rats by up‐regulation of Hsp70 and phosphorylated AMPK (pAMPK). To produce HS, male Sprague–Dawley rats were placed in a chamber with an ambient temperature of 42°C. Physiological function (mean arterial pressure, heart rate and core temperature), hepatic and intestinal injury, inflammatory mediators and levels of Hsp70, pAMPK and light chain 3 (LC3B) in hepatic tissue were measured in HS rats or/and rats pre‐treated with 17‐DMAG. 17‐DMAG pre‐treatment significantly attenuated hypotension and organ dysfunction induced by HS in rats. The survival time during HS was also prolonged by 17‐DMAG treatment. Hsp70 expression was increased, whereas pAMPK levels in the liver were significantly decreased in HS rats. Following pre‐treatment with 17‐DMAG, Hsp70 protein levels increased further, and pAMPK levels were enhanced. Treatment with an AMPK activator significantly increased the LC3BII/LC3BI ratio as a marker of autophagy in HS rats. Treatment with quercetin significantly suppressed Hsp70 and pAMPK levels and reduced the protective effects of 17‐DMAG in HS rats. Both of Hsp70 and AMPK are involved in the 17‐DMAG‐mediated protection against HS. 17‐DMAG may be a promising candidate drug in the clinical setting. 相似文献
100.
Lung-Hsiang Peng Binesh Unnikrishnan Chi-Yu Shih Tung-Ming Hsiung Jeng Chang Pang-Hung Hsu Tai-Chia Chiu Chih-Ching Huang 《Marine biotechnology (New York, N.Y.)》2016,18(2):283-292
In this study, we demonstrate a simple method to identify microalgae by surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) using three different substrates: HgSe, HgTe, and HgTeSe nanostructures. The fragmentation/ionization processes of complex molecules in algae varied according to the heat absorption and transfer efficiency of the nanostructured matrices (NMs). Therefore, the mass spectra obtained for microalgae showed different patterns of m/z values for different NMs. The spectra contained both significant and nonsignificant peaks. Constructing a Venn diagram with the significant peaks obtained for algae when using HgSe, HgTe, and HgTeSe NMs in m/z ratio range 100–1000, a unique relationship among the three sets of values was obtained. This unique relationship of sets is different for each species of microalgae. Therefore, by observing the particular relationship of sets, we successfully identified different algae such as Isochrysis galbana, Emiliania huxleyi, Thalassiosira weissflogii, Nannochloris sp., Skeletonema cf. costatum, and Tetraselmis chui. This simple and cost-effective SALDI-MS analysis method coupled with multi-nanomaterials as substrates may be extended to identify other microalgae and microorganisms in real samples. 相似文献