首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3732篇
  免费   79篇
  国内免费   3篇
  3814篇
  2024年   34篇
  2023年   41篇
  2022年   203篇
  2021年   228篇
  2020年   95篇
  2019年   116篇
  2018年   140篇
  2017年   90篇
  2016年   159篇
  2015年   201篇
  2014年   219篇
  2013年   262篇
  2012年   264篇
  2011年   257篇
  2010年   128篇
  2009年   118篇
  2008年   164篇
  2007年   157篇
  2006年   139篇
  2005年   119篇
  2004年   112篇
  2003年   109篇
  2002年   95篇
  2001年   26篇
  2000年   16篇
  1999年   29篇
  1998年   28篇
  1997年   19篇
  1996年   8篇
  1995年   20篇
  1994年   15篇
  1993年   16篇
  1992年   11篇
  1991年   12篇
  1990年   8篇
  1989年   15篇
  1987年   10篇
  1986年   8篇
  1985年   13篇
  1984年   5篇
  1983年   9篇
  1982年   10篇
  1981年   11篇
  1980年   13篇
  1979年   6篇
  1978年   9篇
  1977年   7篇
  1975年   6篇
  1974年   5篇
  1966年   5篇
排序方式: 共有3814条查询结果,搜索用时 0 毫秒
61.
This paper aims to observe and to study the trends of road traffic accidents (RTA's) for the past ten years in Benghazi-Libya. A retrospective analysis was done using the patient records of Al-Jalaa hospital (the main trauma center in Benghazi) from over 21,753 RTA cases. The annual data were compared to each other and changes of trends were observed. RTA's represented an increasing percentage of Al-Jalaa's case load across the years. Around 41% of these cases needed to undergo surgery. The younger age group (20-29 years of age) formed the majority of cases while there was a trend towards an increasing average age of patients involved in an accident. Male patients were found to be younger than their female counterparts. Males comprised 81.5% while females formed 18.5% of RTA patients. In terms of inpatient duration, most patients stayed in the hospital for less than 1 week. Vehicle occupants (drivers and passengers) were admitted more often than pedestrians. There was a trend across the years towards an increased involvement of vehicle occupants and decrease in the proportion of pedestrians that had to be hospitalized. Additionally, there was a decrease in the fatalities of pedestrians. Overall, most RTA patients were discharged and made to follow-up in outpatient clinics however there was a startling trend towards increased LAMA and absconded patients. There were both encouraging findings as well as points that needed further emphasis and action. Public education, life support training and diversification of transport (apart from the use of the roads) should be looked into, as possible means of improving the current situation.  相似文献   
62.
63.
We describe a generic design for ratiometric analysis suitable for determination of copy number variation (CNV) class of a gene. Following two initial sequence-specific PCR priming cycles, both ends of both amplicons (one test and one reference) in a duplex reaction, are all primed by the same universal primer (UP). Following each amplification denaturation step, the UP target and its reverse complement (UP') in each strand form a hairpin. The bases immediately beyond the 3'-end of the UP and 5' of UP' are chosen such as not to base pair in the hairpin (otherwise priming is ablated). This hairpin creates a single constant environment for priming events and chaperones free 3'-ends of amplicon strands. The resultant 'amplification ratio control system' (ARCS) permits ratiometric representation of amplicons relative to the original template into PCR plateau phase. These advantages circumvent the need for real-time PCR for quantitation. Choice of different %(G+C) content for the target and reference amplicons allows liquid phase thermal melt discrimination and quantitation of amplicons. The design is generic, simple to set up and economical. Comparisons with real-time PCR and other techniques are made and CNV assays demonstrated for haptoglobin duplicon and 'chemokine (C-C motif) ligand 3-like 1' gene.  相似文献   
64.
65.
66.
    
Mitochondrial dysfunction is the main cause of gradual deterioration of structure and function of neuronal cells, eventually resulting in neurodegeneration. Studies have revealed a complex interrelationship between neurotoxicant exposure, mitochondrial dysfunction, and neurodegenerative diseases. Alteration in the expression of microRNAs (miRNAs) has also been linked with disruption in mitochondrial homeostasis and bioenergetics. In our recent research (Cellular and Molecular Neurobiology (2023) https://doi.org/10.1007/s10571-023-01362-4), we have identified miR-29b-3p as one of the most significantly up-regulated miRNAs in the blood of Parkinson's patients. The findings of the present study revealed that neurotoxicants of two different natures, that is, arsenic or rotenone, dramatically increased miR-29b-3p expression (18.63-fold and 12.85-fold, respectively) in differentiated dopaminergic SH-SY5Y cells. This dysregulation of miR-29b-3p intricately modulated mitochondrial morphology, induced oxidative stress, and perturbed mitochondrial membrane potential, collectively contributing to the degeneration of dopaminergic cells. Additionally, using assays for mitochondrial bioenergetics in live and differentiated SH-SY5Y cells, a reduction in oxygen consumption rate (OCR), maximal respiration, basal respiration, and non-mitochondrial respiration was observed in cells transfected with mimics of miR-29b-3p. Inhibition of miR-29b-3p by transfecting inhibitor of miR-29b-3p prior to exposure to neurotoxicants significantly restored OCR and other respiration parameters. Furthermore, we observed that induction of miR-29b-3p activates neuronal apoptosis via sirtuin-1(SIRT-1)/YinYang-1(YY-1)/peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1α)-regulated Bcl-2 interacting protein 3-like-dependent mechanism. Collectively, our studies have shown the role of miR-29b-3p in dysregulation of mitochondrial bioenergetics during degeneration of dopaminergic neurons via regulating SIRT-1/YY-1/PGC-1α axis.  相似文献   
67.
68.
Melioidosis is a tropical bacterial infection caused by Burkholderia pseudomallei (B. pseudomallei; Bpm), a Gram-negative bacterium. Current therapeutic options are largely limited to trimethoprim-sulfamethoxazole and β-lactam drugs, and the treatment duration is about 4 months. Moreover, resistance has been reported to these drugs. Hence, there is a pressing need to develop new antibiotics for Melioidosis. Inhibition of enoyl-ACP reducatase (FabI), a key enzyme in the fatty acid biosynthesis pathway has shown significant promise for antibacterial drug development. FabI has been identified as the major enoyl-ACP reductase present in B. pseudomallei. In this study, we evaluated AFN-1252, a Staphylococcus aureus FabI inhibitor currently in clinical development, for its potential to bind to BpmFabI enzyme and inhibit B. pseudomallei bacterial growth. AFN-1252 stabilized BpmFabI and inhibited the enzyme activity with an IC50 of 9.6 nM. It showed good antibacterial activity against B. pseudomallei R15 strain, isolated from a melioidosis patient (MIC of 2.35 mg/L). X-ray structure of BpmFabI with AFN-1252 was determined at a resolution of 2.3 Å. Complex of BpmFabI with AFN-1252 formed a symmetrical tetrameric structure with one molecule of AFN-1252 bound to each monomeric subunit. The kinetic and thermal melting studies supported the finding that AFN-1252 can bind to BpmFabI independent of cofactor. The structural and mechanistic insights from these studies might help the rational design and development of new FabI inhibitors.  相似文献   
69.
    
Obesity is an established colon cancer risk factor, while preventing or reversing obesity via a calorie restriction (CR) diet regimen decreases colon cancer risk. Unfortunately, the biological mechanisms underlying these associations are poorly understood, hampering development of mechanism-based approaches for preventing obesity-related colon cancer. We tested the hypotheses that diet-induced obesity (DIO) would increase (and CR would decrease) colon tumorigenesis in the mouse azoxymethane (AOM) model. In addition, we established that changes in inflammatory cytokines, growth factors, and microRNAs are associated with these energy balance-colon cancer links, and thus represent mechanism-based targets for colon cancer prevention. Mice were injected with AOM once a week for 5 weeks and randomized to: 1) control diet; 2) 30% CR diet; or 3) DIO diet. Mice were euthanized at week 5 (n = 12/group), 10 (n = 12/group), and 20 (n = 20/group) after the last AOM injection. Colon tumors were counted, and cytokines, insulin-like growth factor 1 (IGF-1), IGF binding protein 3 (IGFBP-3), adipokines, proliferation, apoptosis, and expression of microRNAs (miRs) were measured. The DIO diet regimen induced an obese phenotype (∼36% body fat), while CR induced a lean phenotype (∼14% body fat); controls were intermediate (∼26% body fat). Relative to controls, DIO increased (and CR decreased) the number of colon tumors (p = 0.01), cytokines (p<0.001), IGF-1 (p = 0.01), and proliferation (p<0.001). DIO decreased (and CR increased) IGFBP-3 and apoptosis (p<0.001). miRs including mir-425, mir-196, mir-155, mir-150, mir-351, mir-16, let-7, mir34, and mir-138 were differentially expressed between the dietary groups. We conclude that the enhancing effects of DIO and suppressive effects of CR on colon carcinogenesis are associated with alterations in several biological pathways, including inflammation, IGF-1, and microRNAs.  相似文献   
70.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号