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   145篇
  免费   11篇
  2022年   4篇
  2021年   2篇
  2020年   1篇
  2018年   1篇
  2017年   2篇
  2016年   3篇
  2015年   10篇
  2014年   7篇
  2013年   15篇
  2012年   10篇
  2011年   8篇
  2010年   8篇
  2009年   2篇
  2008年   7篇
  2007年   3篇
  2006年   4篇
  2005年   8篇
  2004年   3篇
  2003年   3篇
  2002年   1篇
  2001年   4篇
  2000年   4篇
  1998年   1篇
  1997年   4篇
  1996年   5篇
  1995年   1篇
  1994年   1篇
  1991年   1篇
  1990年   3篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1983年   2篇
  1980年   1篇
  1979年   1篇
  1976年   1篇
  1974年   3篇
  1973年   1篇
  1972年   4篇
  1971年   1篇
  1968年   1篇
  1966年   2篇
  1965年   2篇
  1964年   1篇
  1960年   1篇
排序方式: 共有156条查询结果,搜索用时 15 毫秒
121.
We report the case of a 52 year old woman that had an adverse reaction after taking a dry herbal extract of an unripe fruit of Citrus aurantium L. var. amara, as dietary supplement for weight loosing. The fruit is also known as zhi shi (in traditional Chinese Medicine) or bitter orange in other parts of the world.  相似文献   
122.
BackgroundRecognising the substantial political weight of the United Nations General Assembly (UNGA), a UN General Assembly special session (UNGASS) and high-level meetings (HLMs) have been pursued and held for 5 health-related topics thus far. They have focused on human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS, 2001), non-communicable diseases (NCDs, 2011), antimicrobial resistance (AMR, 2016), tuberculosis (TB, 2018), and universal health coverage (UHC, 2019). This observational study presents a comprehensive analysis of the political and policy background that prompted the events, as well as an assessment of aims, approaches, and ultimate outcomes.Methods and findingsWe investigated relevant agencies’ official documents, performed a literature search, and accessed international institutions’ websites for the period 1990–2020. Knowledgeable diplomatic staff and experts provided additional information. Outcomes were evaluated from a United Nations perspective based on national and international commitments, and funding trends. Eliciting an effective governmental response through UNGASSs/HLMs is a challenge. However, increased international commitment was evident after the HIV/AIDS (2001), NCDs (2011), and AMR (2016) meetings. The more recent TB (2018) and UHC (2019) HLMs have received general endorsements internationally, although concrete commitments are not yet documented. Although attribution can only be hypothesized, financial investments for HIV/AIDS following the UNGASS were remarkable, whereas following HLMs for NCDs, AMR, and TB, the financial investments remained insufficient to face the burden of these threats. Thus far, the HIV/AIDS UNGASS was the only one followed by a level of commitment that has likely contributed to the reversal of the previous burden trend. Limitations of this study include its global perspective and aerial view that cannot discern the effects at the country level. Additionally, possible peculiarities that modified the response to the meetings were not looked at in detail. Finally, we assessed a small sample of events; thus, the list of strategic characteristics for success is not exhaustive.ConclusionsOverall, UNGASSs and HLMs have the potential to lay better foundations and boldly address key health challenges. However, to succeed, they need to (i) be backed by large consensus; (ii) engage UN authorities and high-level bodies; (iii) emphasise implications for international security and the world economy; (iv) be supported by the civil society, activists, and champions; and (v) produce a political declaration containing specific, measurable, achievable, relevant, and time-bound (SMART) targets. Therefore, to ensure impact on health challenges, in addition to working with the World Health Assembly and health ministries, engaging the higher political level represented by the UNGA and heads of state and government is critical.

Paolo Rodi and colleagues analyze the political and policy response to UN General Assembly and high-level meetings focused on HIV/AIDS, non-communicable diseases, antimicrobial resistance, tuberculosis and universal health coverage.  相似文献   
123.
Burkholderia pseudomallei is a Gram-negative bacterium responsible for melioidosis, a serious and often fatal infectious disease that is poorly controlled by existing treatments. Due to its inherent resistance to the major antibiotic classes and its facultative intracellular pathogenicity, an effective vaccine would be extremely desirable, along with appropriate prevention and therapeutic management. One of the main subunit vaccine candidates is flagellin of Burkholderia pseudomallei (FliCBp). Here, we present the high resolution crystal structure of FliCBp and report the synthesis and characterization of three peptides predicted to be both B and T cell FliCBp epitopes, by both structure-based in silico methods, and sequence-based epitope prediction tools. All three epitopes were shown to be immunoreactive against human IgG antibodies and to elicit cytokine production from human peripheral blood mononuclear cells. Furthermore, two of the peptides (F51-69 and F270-288) were found to be dominant immunoreactive epitopes, and their antibodies enhanced the bactericidal activities of purified human neutrophils. The epitopes derived from this study may represent potential melioidosis vaccine components.  相似文献   
124.
125.
Sharkey MA  Gori A  Capone M  Engel PC 《The FEBS journal》2012,279(17):3003-3009
Active-site mutants of glutamate dehydrogenase from Clostridium?symbiosum have been designed and constructed and the effects on coenzyme preference evaluated by detailed kinetic measurements. The triple mutant F238S/P262S/D263K shows complete reversal in coenzyme selectivity from NAD(H) to NADP(H) with retention of high levels of catalytic activity for the new coenzyme. For oxidized coenzymes, k(cat) /K(m) ratios of the wild-type and triple mutant enzyme indicate a shift in preference of approximately 1.6?×?10(7) -fold, from ~?80?000-fold in favour of NAD(+) to ~?200-fold in favour of NADP(+) . For reduced coenzymes the corresponding figure is 1.7?×?10(4) -fold, from ~?1000-fold in favour of NADH to ~?17-fold in favour of NADPH. A fourth mutation (N290G), previously identified as having a potential bearing on coenzyme specificity, did not engender any further shift in preference when incorporated into the triple mutant, despite having a significant effect when expressed as a single mutant.  相似文献   
126.
The effects of NaCl stress on cell area and intracellular pH (pHi) of individual cells of two Debaryomyces hansenii strains were investigated. Our results show that one of the strains was more NaCl tolerant than the other, as determined by the rate of growth initiation. Whereas NaCl stress caused similar cell shrinkages (30–35%), it caused different pHi changes of the two D. hansenii strains; i.e., in the more NaCl-tolerant strain, pHi homeostasis was maintained, whereas in the less NaCl-tolerant strain, intracellular acidification occurred. Thus, cell shrinkage could not explain the different intracellular acidifications in the two strains. Instead, we introduce the concept of yeasts having an intracellular pKa (pKa,i) value, since permeabilized D. hansenii cells had a very high buffer capacity at a certain pH. Our results demonstrate that the more NaCl-tolerant strain was better able to maintain its pKa,i close to its pHi homeostasis level during NaCl stress. In turn, these findings indicate that the closer a D. hansenii strain can keep its pKa,i to its pHi homeostasis level, the better it may manage NaCl stress. Furthermore, our results suggest that the NaCl-induced effects on pHi were mainly due to hyperosmotic stress and not ionic stress.  相似文献   
127.
n-3 polyunsaturated fatty acids (PUFA) can affect several monocyte functions and the biochemistry of blood cells, thus possibly influencing the initiation of thrombosis, inflammatory disease and atherosclerosis. In this study, we have investigated the effect of dietary supplementation with n-3 PUFA ethyl esters on procoagulant activity (PCA) and interleukin-6 (IL-6) production by human mononuclear cells. Nine healthy volunteers received 4 g/d of n-3 PUFA ethyl esters (4 × 1 g capsules with at least 85% eicosapentaenoic + docosahexaenoic acid ethyl esters) for 18 weeks. Before and at the end of the treatment, mononuclear cells were obtained from peripheral citrated blood by Ficoll-Hypaque density gradient centrifugation. Cellular suspensions (107 cells/ml) were incubated at 37°C for 4 h in the absence and presence of lipopolysaccharide (10 μg/ml); PCA was determined by one-stage clotting assay and IL-6 concentrations were assayed in supernatants by specific ELISA. After 18-week treatment, both unstimulated and stimulated monocyte PCA were significantly reduced by 66% and 63%, respectively (P < 0.01). Similarly, a significant inhibitory effect by n-3 PUFA treatment on basal and LPS-stimulated IL-6 monocyte production was observed (50% and 46%, respectively, P < 0.05). These data indicate that 18-week n-3 PUFA supplementation may influence monocyte activities, which play a specific role in atherosclerosis and its thrombotic complications.  相似文献   
128.
Platelet lipid composition, c arachidonic acid (AA) metabolism by platelets (stimulated with thrombin), serum thromboxane (Tx)B2 production and plasma lipid composition were investigated in 53 healthy females (18-45 years) and 65 males (19-45 years) with similar dietary habits. In males, serum TxB2 production and cholesterol platelet membrane levels were found significantly higher (p less than 0.001 and p less than 0.05) than in females. No differences were observed between the two groups in the AA conversion through cyclo-oxygenase and lipoxygenase pathways or in the platelet phospholipid fatty acid composition. These findings indicate that in males the platelet proaggregatory capacity is greater than in females and the higher platelet TxB2 production does not depend on a larger AA availability or on enzyme activation for its conversion. The increased TxB2 production may be, at least in part, induced by functional differences such as a different membrane cholesterol content inducing, in its turn, an increased microviscosity and/or higher number of platelet receptors for thrombin.  相似文献   
129.
In Nicotiana tabacum L. var. BEL W3 copper (Cu) at concentrations higher than 50 μM significantly inhibited callus growth and shoot regeneration. After 5–6 months of culture only a few morphogenic callus lines survived in the presence of 100 μM Cu. These calluses showed the capacity to grow and regenerate shoots through successive subcultures on medium containing 100 μM Cu. The 100 μM Cu-tolerant shoots, in comparison to regenerated control shoots, formed roots only when cultured in the presence of 100 μM Cu. From five independent Cu-tolerant callus lines in a culture period of 4–5 months more than 50 plants (defined ‘tolerant’) able to grow in presence of 100 μM Cu were obtained. These plants showed normal xylem tissue formation while control regenerated plants growing in normal Cu MS content (0.1 μM) had few xylem elements in the central cylinder. No difference as far chlorophyll content and chloroplast structure was found among Cu-tolerant and control plants. In Cu-tolerant plants, dry matter production was higher than in controls, particularly in roots. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
130.
Hyperhomocysteinemia is a well-known independent marker factor for atherothrombotic diseases and may result from acquired and genetic influences. Several polymorphisms are suspected to be associated with hyperhomocysteinemia, but data are limited and inconsistent. High-throughput genotyping technologies, such as GenomeLab SNPStream, are now available. Moreover, an appropriate selection of SNPs to be analyzed could represent a strong resource to define the role of genetic risk factors. We developed a multiplex PCR-oligonucleotide extension approach by GenomeLab platform. We selected 72 SNPs based on their putative function and frequency in the candidate genes AHCY, BHMT, BHMT2, CBS, ENOSF1, FOLH1, MTHFD1, MTHFR, MTR, MTRR, NNMT, PON1, PON2, SLC19A1, SHMT1, TCN2, and TYMS. We were able to analyze 57 of the SNPs (79%). For MTHFR C677T and A1298C and MTR A2756G SNPs, we compared data obtained with an electronic microchip technology and found 99.2% concordance. We also performed a haplotype analysis. This approach could represent a useful tool to investigate the genotype-phenotype correlation and the association of these genes with hyperhomocysteinemia and correlated diseases.  相似文献   
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