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   224篇
  免费   10篇
  2024年   3篇
  2023年   4篇
  2022年   19篇
  2021年   12篇
  2020年   16篇
  2019年   17篇
  2018年   12篇
  2017年   11篇
  2016年   10篇
  2015年   14篇
  2014年   16篇
  2013年   19篇
  2012年   19篇
  2011年   17篇
  2010年   10篇
  2009年   9篇
  2008年   9篇
  2007年   4篇
  2006年   2篇
  2005年   4篇
  2004年   3篇
  2003年   2篇
  2002年   1篇
  2000年   1篇
排序方式: 共有234条查询结果,搜索用时 843 毫秒
41.
Contamination of soils with copper (Cu) has become a serious problem in the environment. Phytoremediation is an emerging green technology that uses green plants to remediate heavy metal contaminated areas. This study was conducted to evaluate the potential of Jatropha curcas for remediation of soils contaminated with Cu. Seedlings were planted in soils spiked with Cu in amount of 0, 50, 100, 200, 300, and 400 mg kg–1 (Cu0, Cu50,Cu100,Cu200,Cu300, and Cu400) for a period of five months. The maximum height and number of leaves were recorded in control (Cu0) whereas the highest basal stem diameter was found in seedlings exposed to Cu50. Copper concentrations among plant parts were in the following trend: roots > stems > leaves. The highest total Cu concentration (665 ± 1 mg kg?1) and total Cu removal (1.2 ± 0.2%) based on total plant dry biomass were found in Cu400 and Cu50 treatments, respectively. J. curcas exhibited high root concentration factor (RCF > 1) and low translocation factor (TF < 1). Although Cu accumulation by the plant didn't reach the criteria of Cu hyperaccumulators, this species showed a potential to be used in phytostabilization of mildly Cu contaminated areas. However, the plant cannot be used for phytoextraction of Cu-contaminated soils.  相似文献   
42.
The evolution of the influenza A virus to increase its host range is a major concern worldwide. Molecular mechanisms of increasing host range are largely unknown. Influenza surface proteins play determining roles in reorganization of host-sialic acid receptors and host range. In an attempt to uncover the physic-chemical attributes which govern HA subtyping, we performed a large scale functional analysis of over 7000 sequences of 16 different HA subtypes. Large number (896) of physic-chemical protein characteristics were calculated for each HA sequence. Then, 10 different attribute weighting algorithms were used to find the key characteristics distinguishing HA subtypes. Furthermore, to discover machine leaning models which can predict HA subtypes, various Decision Tree, Support Vector Machine, Naïve Bayes, and Neural Network models were trained on calculated protein characteristics dataset as well as 10 trimmed datasets generated by attribute weighting algorithms. The prediction accuracies of the machine learning methods were evaluated by 10-fold cross validation. The results highlighted the frequency of Gln (selected by 80% of attribute weighting algorithms), percentage/frequency of Tyr, percentage of Cys, and frequencies of Try and Glu (selected by 70% of attribute weighting algorithms) as the key features that are associated with HA subtyping. Random Forest tree induction algorithm and RBF kernel function of SVM (scaled by grid search) showed high accuracy of 98% in clustering and predicting HA subtypes based on protein attributes. Decision tree models were successful in monitoring the short mutation/reassortment paths by which influenza virus can gain the key protein structure of another HA subtype and increase its host range in a short period of time with less energy consumption. Extracting and mining a large number of amino acid attributes of HA subtypes of influenza A virus through supervised algorithms represent a new avenue for understanding and predicting possible future structure of influenza pandemics.  相似文献   
43.
Three new eriophyid species (Phyllocoptinae), Shevtchenkella denticulata sp. n., Notallus pestehae sp. n. and Echinacrus ruthenicus sp. n., were described from Eryngium thyrsoideum Boiss. (Apiaceae), Pistacia vera L. (Anacardiaceae) and Lycium ruthenicum Murray (Solanaceae), respectively. All the three new species were collected from southwest of the East Azerbaijan province, Iran in 2011. It is the first record of an eriophyoid mite collected from E. thyrsoideum and L. ruthenicum and the first record of Notallus from Anacardiaceae plant family.  相似文献   
44.
The inflammatory cytokine IL-1β is critical for host responses against many human pathogens. Here, we define Group B Streptococcus (GBS)-mediated activation of the Nod-like receptor-P3 (NLRP3) inflammasome in macrophages. NLRP3 activation requires GBS expression of the cytolytic toxin, β-hemolysin, lysosomal acidification, and leakage. These processes allow the interaction of GBS RNA with cytosolic NLRP3. The present study supports a model in which GBS RNA, along with lysosomal components including cathepsins, leaks out of lysosomes and interacts with NLRP3 to induce IL-1β production.  相似文献   
45.

Background

As primary healthcare professionals, community pharmacists have both opportunity and potential to contribute to the prevention and progression of chronic diseases. Using cardiovascular disease (CVD) as a case study, we explored factors that influence community pharmacists’ everyday practice in this area. We also propose a model to best illustrate relationships between influencing factors and the scope of community pharmacy practice in the care of clients with established CVD.

Methods

In-depth, semi-structured interviews were conducted with 21 community pharmacists in New South Wales, Australia. All interviews were audio-recorded, transcribed ad verbatim, and analysed using a “grounded-theory” approach.

Results

Our model shows that community pharmacists work within a complex system and their practice is influenced by interactions between three main domains: the “people” factors, including their own attitudes and beliefs as well as those of clients and doctors; the “environment” within and beyond the control of community pharmacy; and outcomes of their professional care. Despite the complexity of factors and interactions, our findings shed some light on the interrelationships between these various influences. The overarching obstacle to maximizing the community pharmacists’ contribution is the lack of integration within health systems. However, achieving better integration of community pharmacists in primary care is a challenge since the systems of remuneration for healthcare professional services do not currently support this integration.

Conclusion

Tackling chronic diseases such as CVD requires mobilization of all sources of support in the community through innovative policies which facilitate inter-professional collaboration and team care to achieve the best possible healthcare outcomes for society.  相似文献   
46.
Angiogenesis is a complex process that involves the expansion of the pre-existing vascular plexus to enhance oxygen and nutrient delivery and is stimulated by various factors, including hypoxia. Since the process of angiogenesis requires a lot of energy, mitochondria play an important role in regulating and promoting this phenomenon. Besides their roles as an oxidative metabolism base, mitochondria are potential bioenergetics organelles to maintain cellular homeostasis via sensing alteration in oxygen levels. Under hypoxic conditions, mitochondria can regulate angiogenesis through different factors. It has been indicated that unidirectional and bidirectional exchange of mitochondria or their related byproducts between the cells is orchestrated via different intercellular mechanisms such as tunneling nanotubes, extracellular vesicles, and gap junctions to maintain the cell homeostasis. Even though, the transfer of mitochondria is one possible mechanism by which cells can promote and regulate the process of angiogenesis under reperfusion/ischemia injury. Despite the existence of a close relationship between mitochondrial donation and angiogenic response in different cell types, the precise molecular mechanisms associated with this phenomenon remain unclear. Here, we aimed to highlight the possible role of mitochondria concerning angiogenesis, especially the role of mitochondrial transport and the possible relation of this transfer with autophagy, the housekeeping phenomenon of cells, and angiogenesis.  相似文献   
47.
Epithelial wound healing in Drosophila involves the formation of multinucleate cells surrounding the wound. We show that autophagy, a cellular degradation process often deployed in stress responses, is required for the formation of a multinucleated syncytium during wound healing, and that autophagosomes that appear near the wound edge acquire plasma membrane markers. In addition, uncontrolled autophagy in the unwounded epidermis leads to the degradation of endo‐membranes and the lateral plasma membrane, while apical and basal membranes and epithelial barrier function remain intact. Proper functioning of TORC1 is needed to prevent destruction of the larval epidermis by autophagy, in a process that depends on phagophore initiation and expansion but does not require autophagosomes fusion with lysosomes. Autophagy induction can also affect other sub‐cellular membranes, as shown by its suppression of experimentally induced laminopathy‐like nuclear defects. Our findings reveal a function for TORC1‐mediated regulation of autophagy in maintaining membrane integrity and homeostasis in the epidermis and during wound healing.  相似文献   
48.
Podocyte injury induced by hyperglycemia is the main cause of kidney dysfunction in diabetic nephropathy. However, the underlying mechanism is unclear. Store-operated Ca2+ entry (SOCE) regulates a diversity of cellular processes in a variety of cell types. Calpain, a Ca2+-dependent cysteine protease, was recently shown to be involved in podocyte injury. In the present study, we sought to determine whether increased SOCE contributed to high glucose (HG)–induced podocyte injury through activation of the calpain pathway. In cultured human podocytes, whole-cell patch clamp indicated the presence of functional store-operated Ca2+ channels, which are composed of Orai1 proteins and mediate SOCE. Western blots showed that HG treatment increased the protein abundance of Orai1 in a dose-dependent manner. Consistently, calcium imaging experiments revealed that SOCE was significantly enhanced in podocytes following HG treatment. Furthermore, HG treatment caused overt podocyte F-actin disorganization as well as a significant decrease in nephrin protein abundance, both of which are indications of podocyte injury. These podocyte injury responses were significantly blunted by both pharmacological inhibition of Orai1 using the small molecule inhibitor BTP2 or by genetic deletion of Orai1 using CRISPR-Cas9 lentivirus. Moreover, activation of SOCE by thapsigargin, an inhibitor of Ca2+ pump on the endoplasmic/sarcoplasmic reticulum membrane, significantly increased the activity of calpain, which was inhibited by BTP2. Finally, the calpain-1/calpain-2 inhibitor calpeptin significantly blunted the nephrin protein reduction induced by HG treatment. Taken together, our results suggest that enhanced signaling via an Orai1/SOCE/Calpain axis contributes to HG-induced podocyte injury.  相似文献   
49.
50.
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