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   143篇
  免费   9篇
  国内免费   1篇
  2023年   1篇
  2021年   4篇
  2020年   3篇
  2019年   3篇
  2018年   3篇
  2017年   7篇
  2016年   5篇
  2015年   6篇
  2014年   8篇
  2013年   1篇
  2012年   4篇
  2011年   13篇
  2010年   5篇
  2009年   7篇
  2008年   7篇
  2007年   4篇
  2006年   7篇
  2005年   6篇
  2004年   4篇
  2003年   3篇
  2002年   4篇
  2001年   3篇
  2000年   3篇
  1999年   9篇
  1998年   4篇
  1997年   1篇
  1996年   3篇
  1995年   1篇
  1992年   1篇
  1986年   2篇
  1985年   4篇
  1982年   3篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1972年   1篇
  1971年   2篇
  1970年   2篇
  1969年   1篇
  1968年   1篇
  1966年   1篇
排序方式: 共有153条查询结果,搜索用时 389 毫秒
1.
Histological examination of 69 pairs of infected kidneys from 12 species of Rodentia, Lagomorpha, Carnivora and Insectivora revealed that leptospires were confined mainly to the proximal and distal convoluted tubule, were less often found in the thick loop of Henle and only rarely in the collecting duct. On no occasion were the organisms present in the thin loop of Henle. Preliminary observations on the relationship of leptospires to tubule epithelium indicate some degree of physical attachment. It is suggested that the avoidance of the thin loop of Henle might be a reflection of its structural properties.  相似文献   
2.
3.

Background

Peripheral artery disease (PAD) is an important global health problem and contributes to notable proportion of morbidity and mortality. This particular manifestation of systemic atherosclerosis is largely under diagnosed and undertreated. For sustainable preventive strategies in a country, it is mandatory to identify country-specific risk factors. We intended to assess the risk factors of PAD among adults aged 40–74 years.

Methods

This case control study was conducted in 2012–2013 in Sri Lanka. Seventy-nine cases and 158 controls in the age group of 40–74 years were selected for the study in order to have case to control ratio 1:2. The criterion for selecting cases and control was based on Ankle brachial pressure index (ABPI). Cases were selected from those who had ABPI 0.85 or less (ABPI ≤0.85) in either lower limb. Controls were selected from those ABPI score between 1.18 and 1.28 in both lower limbs. Only newly identified individuals with PAD were selected as cases. Controls were selected from the same geographical location and within the 5 year age group as cases.

Results

The history of diabetes mellitus more than 10 years (OR 5.8, 95% CI 2.2–14.2), history of dyslipidemia for more than 10 years (OR 4.9, 95% CI 2.1–16.2), history of hypertension for more than 10 years (OR 3.8, 95% CI 1.8–12.7) and smoking (OR 2.9, 95% CI 1.2–6.9), elevated HsCRP (OR 3.7, 95% CI 1.2–12.0) and hyperhomocysteinemia (OR 3.0, 95% CI 1.1–8.1) were revealed as country specific significant risk factor of PAD.

Conclusions

Diabetes mellitus, hypertension, dyslipidemia, smoking as well as elevated homocysteine and HsCRP found as risk factors of PAD. Longer the duration or higher level exposure to these risk factors has increased the risk of PAD. These findings emphasis the need for routine screening of PAD among patients with the identified risk factors.
  相似文献   
4.
Aquaculture practices from sub-Saharan Africa are characterised by low production, owing to improper technology. Production can be increased through integrating fish farming with other existing on-farm activities, particularly livestock husbandry. We assessed the role of fish-poultry integration on all male Nile tilapia, Oreochromis niloticus growth performance, yields and economic benefits among smallholder farmers in sub-Saharan Africa, Tanzania. The study also compared phytoplankton species composition, abundance and biomass between the fish-poultry integration and non-integrated system. After 180 days of the experiment, all male O. niloticus cultured under fish-poultry integration exhibited significantly higher growth rates than those in the non-integrated system (p < 0.05). Gross fish yield (GFY), net fish yield (NFY) and net annual yields (NAY) obtained from fish-poultry integration were significantly higher than those from non-integrated system (p < 0.05). Partial enterprise budget analysis revealed that fish-poultry integration was more profitable than the non-integrated system. Moreover, fish-poultry integrated system produced significantly higher phytoplankton abundance and biomass than those from the non-integrated system. Results demonstrate that rural smallholder farmers can achieve higher growth rate, farm net yields and income by integrating all male O. niloticus with other on-farm activities than practising a stand-alone fish culture system.  相似文献   
5.
6.
OGL-20P(T)-358 is a novel 66 amino acid residue protein from the hyperthermophile Thermococcus thioreducens sp. nov., strain OGL-20PT, which was collected from the wall of the hydrothermal black smoker in the Rainbow Vent along the mid-Atlantic ridge. This protein, which has no detectable sequence homology with proteins or domains of known function, has a calculated pI of 4.76 and a molecular mass of 8.2 kDa. We report here the backbone 1H, 15N, and 13C resonance assignments of OGL-20PT-358. Assignments are 97.5% (316/324) complete. Chemical shift index was used to determine the secondary structure of the protein, which appears to consist of primarily alpha-helical regions. This work is the foundation for future studies to determine the three-dimensional solution structure of the protein.  相似文献   
7.

Background

A recent epidemiological study demonstrated a reduced risk of lung cancer mortality in breast cancer patients using antiestrogens. These and other data implicate a role for estrogens in lung cancer, particularly nonsmall cell lung cancer (NSCLC). Approximately 61% of human NSCLC tumors express nuclear estrogen receptor β (ERβ); however, the role of ERβ and estrogens in NSCLC is likely to be multifactorial. Here we tested the hypothesis that proteins interacting with ERβ in human lung adenocarcinoma cells that respond proliferatively to estradiol (E2) are distinct from those in non-E2-responsive cells.

Methods

FLAG affinity purification of FLAG-ERβ-interacting proteins was used to isolate ERβ-interacting proteins in whole cell extracts from E2 proliferative H1793 and non-E2-proliferative A549 lung adenocarcinoma cell lines. Following trypsin digestion, proteins were identified using liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS). Proteomic data were analyzed using Ingenuity Pathway Analysis. Select results were confirmed by coimmunoprecipitation.

Results

LC-MS/MS identified 27 non-redundant ERβ-interacting proteins. ERβ-interacting proteins included hsp70, hsp60, vimentin, histones and calmodulin. Ingenuity Pathway Analysis of the ERβ-interacting proteins revealed differences in molecular and functional networks between H1793 and A549 lung adenocarcinoma cells. Coimmunoprecipitation experiments in these and other lung adenocarcinoma cells confirmed that ERβ and EGFR interact in a gender-dependent manner and in response to E2 or EGF. BRCA1 interacted with ERβ in A549 cell lines and in human lung adenocarcinoma tumors, but not normal lung tissue.

Conclusion

Our results identify specific differences in ERβ-interacting proteins in lung adenocarcinoma cells corresponding to ligand-dependent differences in estrogenic responses.
  相似文献   
8.

Background

Persons with Chronic Obstructive Pulmonary Disease (COPD), performing some level of regular physical activity, have a lower risk of both COPD-related hospital admissions and mortality. COPD patients of all stages seem to benefit from exercise training programs, thereby improving with respect to both exercise tolerance and symptoms of dyspnea and fatigue. Physical inactivity, which becomes more severe with increasing age, is a point of concern in healthy older adults. COPD might worsen this scenario, but it is unclear to what degree. This literature review aims to present the extent of the impact of COPD on objectively-measured daily physical activity (DPA). The focus is on the extent of the impact that COPD has on duration, intensity, and counts of DPA, as well as whether the severity of the disease has an additional influence on DPA.

Results

A literature review was performed in the databases PubMed [MEDLINE], Picarta, PEDRO, ISI Web of Knowledge and Google scholar. After screening, 11 studies were identified as being relevant for comparison between COPD patients and healthy controls with respect to duration, intensity, and counts of DPA. Four more studies were found to be relevant to address the subject of the influence the severity of the disease may have on DPA. The average percentage of DPA of COPD patients vs. healthy control subjects for duration was 57%, for intensity 75%, and for activity counts 56%. Correlations of DPA and severity of the disease were low and/or not significant.

Conclusions

From the results of this review, it appears that patients with COPD have a significantly reduced duration, intensity, and counts of DPA when compared to healthy control subjects. The intensity of DPA seems to be less affected by COPD than duration and counts. Judging from the results, it seems that severity of COPD is not strongly correlated with level of DPA. Future research should focus in more detail on the relation between COPD and duration, intensity, and counts of DPA, as well as the effect of disease severity on DPA, so that these relations become more understandable.  相似文献   
9.
CCN-2, also known as connective tissue growth factor (CCN-2/CTGF) is a cysteine rich, extracellular matrix protein that acts as a pro-fibrotic cytokine in tissues in many diseases, including in diabetic nephropathy. We have published that soluble advanced glycation end products (AGEs), that are present in increased amounts in diabetes, induce CCN-2. However in vivo AGEs are known to be heavily tissue bound and whether matrix bound AGEs regulate CCN-2 has not been investigated. In this study we determined in human renal mesangial cells if CCN-2 is induced by matrix associated AGEs and if CCN-2 may then secondarily mediate effects of matrix AGEs on extracellular matrix expansion. Data generated show that CCN-2 mRNA and protein expression are induced by matrix bound AGEs, and in contrast, this was not the case for TGF-β1 mRNA regulation. Using CCN-2 adenoviral anti-sense it was found that CCN-2 mediated the up-regulation of fibronectin and the tissue inhibitor of matrix metalloproteinase, TIMP-1, that was caused by matrix bound AGEs. In conclusion, CCN-2 is induced by non-enzymatically glycated matrix and it mediates downstream fibronectin and TIMP-1 increases, thus through this mechanism potentially contributing to ECM accumulation in the renal glomerulus in diabetes.  相似文献   
10.
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