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Dissolved organic carbon (DOC) and nitrogen (DON) concentrations were quantified in urban and rural watersheds located in central Texas, USA between 2007 and 2008. The proportion of urban land use ranged from 6 to 100% in our 12 study watersheds which included nine watersheds without waste water treatment plants (WWTP) and three watersheds sampled downstream of a WWTP. Annual mean DOC concentrations ranged 20.4–52.5 mg L?1. Annual mean DON concentrations ranged 0.6–1.9 mg L?1. Only the rural watersheds without a WWTP had significantly lower DOC concentrations compared to those watersheds with a WWTP but all the streams except two had significantly reduced DON compared to those with a WWTP. Analysis of the nine watersheds without a WWTP indicated that 68% of the variability in mean annual DOC concentration was explained by urban open areas such as golf courses, sports fields and neighborhood parks under turf grass. There was no relationship between annual mean DON concentration and any land use. Urban open area also explained a significant amount of the variance in stream sodium and stream sodium adsorption ratio (SAR). Ninety-four percent of the variance in annual mean DOC concentration was explained by SAR. Irrigation of urban turf grass with domestic tap water high in sodium (>181 mg Na+ L?1) may be inducing sodic soil conditions in watershed soils in this region resulting in elevated mean annual DOC concentrations in our streams. 相似文献
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Entamoeba histolytica infection is associated with considerable morbidity and mortality in the form of intestinal and extraintestinal amoebiasis. No vaccine is yet available for amoebiasis. Heparan Sulphate Binding Proteins (HSBPs) from E. histolytica were evaluated for immunogenicity and protective efficacy in a Guinea pig model. Animals were immunized subcutaneously with 30 μg of HSBP by three weekly inoculations. The immunogenicity of HSBP was determined by antibody response (IgG, IgM and IgA), splenocyte proliferation assay and in vitro direct amoebicidal assay with splenic lymphocytes and monocytes from vaccinated and control animals. The efficacy of the vaccine was evaluated by challenge infection to vaccinated and control animals by intra-caecal inoculation of E. histolytica trophozoites and comparing gross and histopathological findings in caeca of these animals. HSBP was found to induce specific anti-amoebic response as seen by specific antibody production and direct amoebicidal activity of splenocytes. The vaccine also showed partial protection against challenge infection in vaccinated animals as shown by mild/absent lesions and histopathological findings. 相似文献
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Shehab DK Al-Jarallah KF Al-Awadhi AM Al-Herz A Nahar I Haider MZ 《Journal of biomedical science》2008,15(1):61-67
Summary Low back pain (LBP) is a common medical problem. Interaction between genetic and environmental factors predisposes individuals
to LBP even at an early age. Inflammatory back pain or spondylarthropathies include ankylosing spondylitis (AS), psoriatic
arthritis (PSA), reactive arthritis enteropathic and undifferentiated arthropathies. Angiotensin-converting enzyme (ACE) plays
an important role in circulatory homeostasis, physiology of vasculature and inflammation. The insertion–deletion (I/D) polymorphism
of the ACE gene has been shown to determine the plasma and tissue levels of ACE especially in the synovial fluid. The aim
of this study was to investigate an association between ACE gene I/D polymorphism and inflammatory back pain (spondylarthropathies)
secondary to ankylosing spondylitis (AS), psoriatic arthritis, inflammatory bowel disease and undifferentiated spondylarthropathies.
The prevalence of ACE gene I/D polymorphism genotypes was determined in 63 patients with inflammatory back pain by polymerase
chain reaction (PCR) and compared with that in 111 healthy controls. Of the 63 patients studied, 45 (71.4%) were with AS,
13 (20.6%) were with PSA, 4 (6.3%) were with reactive arthropathy and 1 (1.6%) manifested undifferentiated arthropathy. There
were 43 males and 20 females. Mean age of patients was 39.0 ± 11.36 years, age at onset of spondylarthropathy was 27.7 ± 7.49 years
and disease duration was 10.3 ± 7.74 months. The controls were selected to match with the patients group in terms of gender
ratio, age and ethnicity. The ACE gene polymorphism showed an overall significant difference between patients and controls
(p = 0.050). When the ID and II genotype frequency was combined and compared with that for DD genotype amongst patient and control
groups, a considerably higher incidence was detected for ID and II genotypes than the DD genotype in spondylarthropathy patients
compared to that in the controls (p = 0.036). This study showed a significant association of the I-allele of ACE gene I/D polymorphism with spondylarthropathy
in Kuwaiti Arabs. 相似文献
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Background
Leprosy is remaining prevalent in the poorest areas of the world. Intensive control programmes with multidrug therapy (MDT) reduced the number of registered cases in these areas, but transmission of Mycobacterium leprae continues in most endemic countries. Socio-economic circumstances are considered to be a major determinant, but uncertainty exists regarding the association between leprosy and poverty. We assessed the association between different socio-economic factors and the risk of acquiring clinical signs of leprosy.Methods and Findings
We performed a case-control study in two leprosy endemic districts in northwest Bangladesh. Using interviews with structured questionnaires we compared the socio-economic circumstances of recently diagnosed leprosy patients with a control population from a random cluster sample in the same area. Logistic regression was used to compare cases and controls for their wealth score as calculated with an asset index and other socio-economic factors. The study included 90 patients and 199 controls. A recent period of food shortage and not poverty per se was identified as the only socio-economic factor significantly associated with clinical manifestation of leprosy disease (OR 1.79 (1.06–3.02); p = 0.030). A decreasing trend in leprosy prevalence with an increasing socio-economic status as measured with an asset index is apparent, but not statistically significant (test for a trend: OR 0.85 (0.71–1.02); p = 0.083).Conclusions
Recent food shortage is an important poverty related predictor for the clinical manifestation of leprosy disease. Food shortage is seasonal and poverty related in northwest Bangladesh. Targeted nutritional support for high risk groups should be included in leprosy control programmes in endemic areas to reduce risk of disease. 相似文献50.