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61.
1-substituted cyclopropenes: Effective Blocking Agents for Ethylene Action in Plants 总被引:5,自引:0,他引:5
Edward C. Sisler Thair Alwan Raphael Goren Margrethe Serek Akiva Apelbaum 《Plant Growth Regulation》2003,40(3):223-228
A series of 1-alkane substituted cyclopropenes has been prepared and tested as ethylene antagonists using banana fruits as an assay system. 1-Methyl-, 1-ethyl-, 1-propyl-, 1-butyl-, 1-pentyl-, 1-hexyl-, 1-heptyl-, 1-octyl-, 1-nonyl-, and 1-decylcyclopropene were all very active compounds. 1-Methylcyclopropene protected bananas from ethylene with a minimum concentration of 0.7 nl.l–1 after a 24 h exposure. As the carbon chain length was extended the minimum requirement increased some, but starting with 1-butylcyclopropene, the minimum concentration requirement declined and many cyclopropenes were required in lower concentrations than 1-methylcyclopropene. The time of protection at ambient temperature (22–23 °C) was 12 d for 1-methyl-, 1-ethyl-, 1-propyl-, and 1-butylcyclopropene. 1-Pentylcyclopropene protected bananas for 14 d, 1-hexylcyclopropene for 20 d, 1-heptylcyclopropene for 21 d, 1-octylcyclopropene for 25 d, 1-nonylcyclopropene for 35 d, and 1-decylcyclopropene for 36 d. 相似文献
62.
Journal of Ichthyology - This paper presents the results of a comparative study of eight osteological characters: the counts, dimension and regionalization of the vertebral column, the pattern of... 相似文献
63.
64.
Mehran Kausar Saima Siddiqi Muhammad Yaqoob Sajid Mansoor Outi Makitie Asif Mir Chiea Chuen Khor Jia Nee Foo Mariam Anees 《Journal of biomedical science》2018,25(1):82
Introduction
Osteogenesis imperfecta (OI) is a clinically and genetically heterogeneous disease with skeletal fragility and variable extra-skeletal manifestations. To date several point mutations in 18 different genes causing different types of OI have been identified. Mutations in WNT1 compromise activity of the osteoblasts leading to disturbed bone mass accrual, fragility fractures and progressive skeletal abnormalities. The present study was conducted to determine the underlying genetic cause of an autosomal recessive skeletal dysplasia in a large consanguineous family from Chinute, Pakistan.Materials and methods
Blood was collected from 24 individuals of affected family along with clinical data. Homozygosity mapping was performed to confirm consanguinity. SNPs were identified, followed by whole exome and Sanger sequencing. In silico characterization of WNT1 mutation was performed using multiple platforms.Results
Nine affected family members exhibited severe bone deformities, recurrent fractures, short stature and low bone mineral density. SNP array data revealed homozygous segments >?1 Mb in length accounting for 2.1–12.7% of the genome in affected individuals and their siblings and a single 6,344,821 bp homozygous region in all affected individuals on chromosome 12q12-q13. This region includes two potential OI candidate genes WNT1 and VDR. We did whole-exome sequencing for both genes in two patients and identified a novel damaging missense mutation in exon 4 of WNT1: c.1168G?>?T (NM_005430) resulting in p.G324C. Sanger sequencing confirmed segregation of mutation with the disease in family.Conclusion
We report a novel mutation responsible for OI and our investigation expands the spectrum of disease-causing WNT1 mutations and the resulting OI phenotypes.65.
CDK9‐mediated phosphorylation controls the interaction of TIP60 with the transcriptional machinery 下载免费PDF全文
66.
George Burjanadze Mariam Shengelia Natalia Dachanidze Mariam Mikadze Ketevan Menabde Nana Koshoridze 《Biological Rhythm Research》2018,49(1):61-75
Disturbances in natural Circadian rhythm are well-known stress factors, affecting a range of metabolic pathways in the living body including the brain. Hence, discovery of natural compounds that could help to prevent and cure of adverse changes is very important. One of the recently discussed substances is creatine, that is believed to have anti-stressor properties. Recent paper describes the impact of intraperitoneally injected creatine (140 mg/kg) into rats with a disturbed natural circadian rhythm for an extended period of time (30 days). Markedly, creatine-treated animals show positive changes in open-field behavioral parameters, and an increase in certain antioxidant enzymes’ (SOD, catalase) activity in the hippocampus, whereas the concentration of nitric oxide, H2O2, and Ca2+ are approximated to the control value. Similar findings were also observed in case of Na+/K+- and Ca2+-ATPases. To sum up, the recent findings allow the conclusion that oxidative stress induced by long-term disturbances in natural circadian rhythm is accompanied and likely provoked by an increase in Ca2+-cytotoxicity, which is supposedly normalized by the creatine’s indirect action on the NMDA receptor. Therefore, impact on energy mediating pathways has a positive effect on stabilization of antioxidant and various metabolic systems and protecting hippocampal cells from stress. 相似文献
67.
Lalla Aicha Rifai Noureddine Mazoir Tayeb Koussa Mariam El Ghali Amal Smaili Kacem Makroum Malika Belfaiza Ahmed Benharref Mohamed Faize 《Acta Physiologiae Plantarum》2018,40(3):57
This work focused on the effect triterpene derivative 24-methylen-elemo-lanosta-8,24-dien-3-one (F3) on the induction of salt stress tolerance of the Moroccan grapevine cv. “Doukkali”. Hardwood cuttings of the grapevine from a homogeneous plant material collected in the field were grown in hydroponic medium under different salt concentrations and treated with 50 or 100 µg ml?1 of F3. Salt stress affected several physiological and biochemical parameters including relative water content, chlorophyll a and b content, peroxidase, and polyphenol oxidase activities, which decreased along with time. Meanwhile, proline, proteins, soluble sugars, H2O2, and carotenoid content, as well as phenolic compound content increased, suggesting an evidence of tolerance of this local variety to salinity. An exogenous supply of the triterpenic product increased all these parameters under normal conditions. In addition, F3 at low dose was found to be successful in lowering Na+ content and alleviating the inhibitory effects of salt stress on relative water content as well as on chlorophyll a and b. 相似文献
68.
Margaret L. Rodgers U. Sandy Tretbar Alexander Dehaven Amir A. Alwan George Luo Hannah M. Mast Aaron A. Hoskins 《RNA (New York, N.Y.)》2016,22(2):225-236
The spliceosome undergoes dramatic changes in both small nuclear RNA (snRNA) composition and structure during assembly and pre-mRNA splicing. It has been previously proposed that the U2 snRNA adopts two conformations within the stem II region: stem IIa or stem IIc. Dynamic rearrangement of stem IIa into IIc and vice versa is necessary for proper progression of the spliceosome through assembly and catalysis. How this conformational transition is regulated is unclear; although, proteins such as Cus2p and the helicase Prp5p have been implicated in this process. We have used single-molecule Förster resonance energy transfer (smFRET) to study U2 stem II toggling between stem IIa and IIc. Structural interconversion of the RNA was spontaneous and did not require the presence of a helicase; however, both Mg2+ and Cus2p promote formation of stem IIa. Destabilization of stem IIa by a G53A mutation in the RNA promotes stem IIc formation and inhibits conformational switching of the RNA by both Mg2+ and Cus2p. Transitioning to stem IIa can be restored using Cus2p mutations that suppress G53A phenotypes in vivo. We propose that during spliceosome assembly, Cus2p and Mg2+ may work together to promote stem IIa formation. During catalysis the spliceosome could then toggle stem II with the aid of Mg2+ or with the use of functionally equivalent protein interactions. As noted in previous studies, the Mg2+ toggling we observe parallels previous observations of U2/U6 and Prp8p RNase H domain Mg2+-dependent conformational changes. Together these data suggest that multiple components of the spliceosome may have evolved to switch between conformations corresponding to open or closed active sites with the aid of metal and protein cofactors. 相似文献
69.
70.
Hao Jiang Vilen Movsesyan Donald W. Fink Jr. Monika Fasler Michael Whalin Yasuhiro Katagiri Mariam Monshipouri Geneva Dickens Peter I. Lelkes Gordon Guroff Philip Lazarovici 《Journal of cellular biochemistry》1997,66(2):229-244
Nerve growth factor (NGF) regulates proliferation, differentiation, and survival of sympathetic and sensory neurons through the tyrosine kinase activity of its receptor, p140trk. These biological effects of NGF depend upon the signal-mediating function of p140trk substrates which are likely to differ from cell to cell. To define p140trk receptor substrates and the details of signalling by NGF in the hybrid cell PC12EN, we stably transfected cultures with a vector encoding a full-length human p140trk cDNA sequence. Two stably transfected clones, one expressing p140trk with higher affinity (PC12EN-trk3; Kd 57.4 pM, Bmax 9.7 pmole/mg) and one expressing p140trk with a lower affinity (PC12EN-trk1; Kd 392.4 pM, Bmax 5.7 pmole/mg) were generated. Radioreceptor assays indicate that transfected p140trk receptors show slow NGF-dissociation kinetics, are resistant to trypsin or Triton X-100 treatment, are specific for NGF compared to other neurotrophins, and are internalized or downregulated as are native PC12 p140trk receptors. NGF stimulates p140trk tyrosine phosphorylation in a dose- (0.01-10 ng/ml) and time- (5-120 min) dependent manner, and tyrosine phosphorylation was inhibited by 200-1,000 nM K-252a. NGF-induced Erk stimulation for 60 min was assessed using myelin basic protein as a substrate. NGF treatment also led to an increased phosphorylation of p70S6k, SNT, and phospholipase Cγ, demonstrating that the major NGF-stimulated signalling pathways found in other cells are activated in PC12EN-trk cells. Staurosporine (5-50 nM) rapidly and dBcAMP (1 mM) more slowly, but not NGF induced morphological differentiation in PC12EN-trk cells. Rather, NGF treatment in low-serum medium stimulated a 1.3- and 2.3-fold increase in DNA synthesis measured by [3H]thymidine incorporation in PC12EN-trk1 and PC12EN-trk3, respectively. These data highlight the functionality of the transfected p140trk receptors and indicate that these transfected cells may serve as a novel cellular model facilitating the study of the mitogenic properties of NGF signalling and the transducing role of the p140trk receptor substrates. J. Cell. Biochem. 66:229-244. © 1997 Wiley-Liss, Inc. This article is a U.S. Government work and, as such, is in the public domain in the United States of America. 相似文献