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Circadian clocks use a wide range of environmental cues, including cycles of light, temperature, food, and social interactions, to fine-tune rhythms in behavior and physiology. Although social cues have been shown to influence circadian clocks of a variety of organisms including the fruit fly Drosophila melanogaster, their mechanism of action is still unclear. Here, the authors report the results of their study aimed at investigating if daily cycles of presence and absence (PA) of conspecific male visitors are able to entrain the circadian locomotor activity rhythm of male hosts living under constant darkness (DD). The results suggest that PA cycles may not be able to entrain circadian locomotor activity rhythms of Drosophila. The outcome does not change when male hosts are presented with female visitors, suggesting that PA cycles of either sex may not be effective in bringing about stable entrainment of circadian clocks in D. melanogaster. However, in hosts whose clock phase has already been set by light/dark (LD) cycles, daily PA cycles of visitors can cause measurable change in the phase of subsequent free-running rhythms, provided that their circadian clocks are labile. Thus, the findings of this study suggest that D. melanogaster males may not be using cyclic social cues as their primary zeitgeber (time cue) for entrainment of circadian clocks, although social cues are capable of altering the phase of their circadian rhythms. 相似文献
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Saedi M Vaisi-Raygani A Khaghani S Shariftabrizi A Rezaie M Pasalar P Rahimi Z Pourmotabbed T 《Molecular biology reports》2012,39(1):555-562
The Matrix metalloproteinas-9 functional promoter polymorphism 1562C>T may be considered an important genetic determinant
of early-onset coronary artery disease (ECAD). In this study, association between MMP-9 1562C>T allele with plasma MMP-9 activity,
homocysteine and lipid–lipoproteins level and ECAD in Iranian subjects was investigated. This case–control study consisted
of 53 ECAD patients (age < 55 years) and unrelated late-onsets CAD (age > 70 years) who angiographically had at least 50%
stenosis. MMP-9 1562C>T polymorphism was detected by PCRRFLP, plasma MMP-9 activity, serum lipid and homocysteine levels were
determined by gelatin gel zymography, enzyme assay and by HPLC, respectively. The presence of MMP-9 1562C>T allele was found
to be associated with ECAD (OR = 3.2, P = 0.001). The ECAD patients with MMP-9 1562C>T allele had higher MMP-9 activity (P = 0.001), LDL-C (P = 0.045), TC (P = 0.02) and homocysteine (P = 0.01) levels than the LCAD subjects. MMP-9 1562C>T allele is a risk factor for ECAD. The carriers of this allele have high
levels of MMP-9 activity, LDL-C, TC and homocysteine (P = 0.01), thus, are more likely to develop myocardial infarction and CAD at young age (less than 55 years). 相似文献
15.
Huge V Lauchart M Förderreuther S Kaufhold W Valet M Azad SC Beyer A Magerl W 《PloS one》2008,3(7):e2742
Background
Sensory abnormalities are a key feature of Complex Regional Pain Syndrome (CRPS). In order to characterise these changes in patients suffering from acute or chronic CRPS I, we used Quantitative Sensory Testing (QST) in comparison to an age and gender matched control group.Methods
61 patients presenting with CRPS I of the upper extremity and 56 healthy subjects were prospectively assessed using QST. The patients'' warm and cold detection thresholds (WDT; CDT), the heat and cold pain thresholds (HPT; CPT) and the occurrence of paradoxical heat sensation (PHS) were observed.Results
In acute CRPS I, patients showed warm and cold hyperalgesia, indicated by significant changes in HPT and CPT. WDT and CDT were significantly increased as well, indicating warm and cold hypoaesthesia. In chronic CRPS, thermal hyperalgesia declined, but CDT as well as WDT further deteriorated. Solely patients with acute CRPS displayed PHS. To a minor degree, all QST changes were also present on the contralateral limb.Conclusions
We propose three pathomechanisms of CRPS I, which follow a distinct time course: Thermal hyperalgesia, observed in acute CRPS, indicates an ongoing aseptic peripheral inflammation. Thermal hypoaesthesia, as detected in acute and chronic CRPS, signals a degeneration of A-delta and C-fibres, which further deteriorates in chronic CRPS. PHS in acute CRPS I indicates that both inflammation and degeneration are present, whilst in chronic CRPS I, the pathomechanism of degeneration dominates, signalled by the absence of PHS. The contralateral changes observed strongly suggest the involvement of the central nervous system. 相似文献16.
Shahnaz Ibrahim Saadia Maqbool Maleeha Azam Mohammad Perwaiz Iqbal Raheel Qamar 《Molecular biology reports》2018,45(3):353-360
Three index patients with hyperhomocysteinemia and ocular anomalies were screened for cystathionine beta synthase (CBS) and methylenetetrahydrofolate reductase (MTHFR) polymorphisms. Genotyping of hyperhomocysteinemia associated MTHFR polymorphisms C677T (rs1801133) and A1298C (rs1801131) was done by PCR-restriction fragment length polymorphism. Sanger sequencing was performed for CBS exonic sequences along with consensus splice sites. In the case of MTHFR polymorphisms, all the patients were heterozygous CT for the single nucleotide polymorphism (SNP) C677T and were therefore carriers of the risk allele (T), while the patients were homozygous CC for the risk genotype of the SNP A1298C. CBS sequencing resulted in the identification of two novel mutations, a missense change (c.467T>C; p.Leu156Pro) in exon 7 and an in-frame deletion (c.808_810del; p.Glu270del) in exon 10. In addition, a recurrent missense mutation (c.770C>T; p.Thr257Met) in exon 10 of the gene was also identified. The mutations were present homozygously in the patients and were inherited from the carrier parents. This is the first report from Pakistan where novel as well as recurrent CBS mutations causing hyperhomocysteinemia and lens dislocation in three patients from different families are being reported with the predicted effect of the risk allele of the MTHFR SNP in causing hyperhomocysteinemia. 相似文献
17.
Fayaz S Fard-Esfahani P Fard-Esfahani A Mostafavi E Meshkani R Mirmiranpour H Khaghani S 《Genetics and molecular biology》2012,35(1):32-37
Homologous recombination (HR) is the major pathway for repairing double strand breaks (DSBs) in eukaryotes and XRCC2 is an essential component of the HR repair machinery. To evaluate the potential role of mutations in gene repair by HR in individuals susceptible to differentiated thyroid carcinoma (DTC) we used high resolution melting (HRM) analysis, a recently introduced method for detecting mutations, to examine the entire XRCC2 coding region in an Iranian population. HRM analysis was used to screen for mutations in three XRCC2 coding regions in 50 patients and 50 controls. There was no variation in the HRM curves obtained from the analysis of exons 1 and 2 in the case and control groups. In exon 3, an Arg(188)His polymorphism (rs3218536) was detected as a new melting curve group (OR: 1.46; 95%CI: 0.432-4.969; p = 0.38) compared with the normal melting curve. We also found a new Ser(150)Arg polymorphism in exon 3 of the control group. These findings suggest that genetic variations in the XRCC2 coding region have no potential effects on susceptibility to DTC. However, further studies with larger populations are required to confirm this conclusion. 相似文献
18.
Leila Hatami-Baroogh Shahnaz Razavi Hamid Zarkesh-Esfahani Marziyeh Tavalaee Somayeh Tanhaei Kamran Ghaedi Mohamad Reza Deemeh Farzaneh Rabiee Mohammad Hossein Nasr-Esfahani 《Reproductive biology and endocrinology : RB&E》2010,8(1):17
Background
Leptin, a 167 amino acid peptide hormone, profoundly effects reproduction exerting its biological effects via interaction with the leptin receptor (ObR) which is widely expressed on peripheral tissues. In this study, we have attempted to assess leptin receptor expression in the spermatozoa of fertile males and those diagnosed with male factor infertility; both at the mRNA or protein levels. 相似文献19.
Dawar Khadim Rahman Umar Alam Syed Sartaj Tariq Mohammad Khan Aamir Fahad Shah Datta Rahul Danish Subhan Saud Shah Noor Muhammad 《Journal of Plant Growth Regulation》2022,41(1):216-226
Journal of Plant Growth Regulation - The field experiment was conducted to investigate the effects of applying urea with nitrification inhibitor (NI) (Nitrapyrine) alone or in combination with... 相似文献
20.
Saber Hamdani Hongru Wang Guangyong Zheng Shahnaz Perveen Mingnan Qu Naveed Khan Waqasuddin Khan Jianjun Jiang Ming Li Xinyu Liu Xiaocen Zhu Govindjee Chengcai Chu Xin‐Guang Zhu 《Physiologia plantarum》2019,166(1):105-119
The maximum quantum yield of photosystem II (as reflected by variable to maximum chlorophyll a fluorescence, Fv/Fm) is regarded as one of the most important photosynthetic parameters. The genetic basis underlying natural variation in Fv/Fm, which shows low level of variations in plants under non‐stress conditions, is not easy to be exploited using the conventional gene cloning approaches. Thus, in order to answer this question, we have followed another strategy: we used genome‐wide association study (GWAS) and transgenic analysis in a rice mini‐core collection. We report here that four single‐nucleotide polymorphisms, located in the promoter region of β‐glucosidase 5 (BGlu‐5), are associated with observed variation in Fv/Fm. Indeed, our transgenic analysis showed a good correlation between BGlu‐5 and Fv/Fm. Thus, our work demonstrates the feasibility of using GWAS to study natural variation in Fv/Fm, suggesting that cis‐element polymorphism, affecting the BGlu‐5 expression level, may, indirectly, contribute to Fv/Fm variation in rice through the gibberellin signaling pathway. Further research is needed to understand the mechanism of our novel observation. 相似文献