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   707篇
  免费   37篇
  2023年   3篇
  2022年   10篇
  2021年   22篇
  2020年   7篇
  2019年   19篇
  2018年   17篇
  2017年   11篇
  2016年   31篇
  2015年   36篇
  2014年   33篇
  2013年   45篇
  2012年   68篇
  2011年   53篇
  2010年   26篇
  2009年   22篇
  2008年   46篇
  2007年   38篇
  2006年   48篇
  2005年   30篇
  2004年   27篇
  2003年   23篇
  2002年   22篇
  2001年   5篇
  2000年   3篇
  1999年   8篇
  1998年   4篇
  1996年   4篇
  1995年   3篇
  1994年   4篇
  1993年   3篇
  1992年   3篇
  1991年   4篇
  1990年   3篇
  1987年   3篇
  1982年   2篇
  1980年   2篇
  1979年   5篇
  1978年   2篇
  1977年   2篇
  1973年   3篇
  1970年   4篇
  1969年   2篇
  1968年   2篇
  1966年   5篇
  1965年   3篇
  1964年   3篇
  1960年   2篇
  1958年   3篇
  1957年   3篇
  1956年   2篇
排序方式: 共有744条查询结果,搜索用时 15 毫秒
31.
BackgroundDisease and disability from alcohol use disproportionately impact people in low- and middle-income countries (LMICs). While varied interventions have been shown to reduce alcohol use in high-income countries, their efficacy in LMICs has not been assessed. This systematic review describes current published literature on patient-level alcohol interventions in LMICs and specifically describes clinical trials evaluating interventions to reduce alcohol use in LMICs.Methods and findingsIn accordance with PRISMA, we performed a systematic review using an electronic search strategy from January 1, 1995 to December 1, 2020. Title, abstract, as well as full-text screening and extraction were performed in duplicate. A meta-summary was performed on randomized controlled trials (RCTs) that evaluated alcohol-related outcomes. We searched the following electronic databases: PubMed, EMBASE, Scopus, Web of Science, Cochrane, WHO Global Health Library, and PsycINFO. Articles that evaluated patient-level interventions targeting alcohol use and alcohol-related harm in LMICs were eligible for inclusion. No studies were excluded based on language.After screening 5,036 articles, 117 articles fit our inclusion criteria, 75 of which were RCTs. Of these RCTs, 93% were performed in 13 middle-income countries, while 7% were from 2 low-income countries. These RCTs evaluated brief interventions (24, defined as any intervention ranging from advice to counseling, lasting less than 1 hour per session up to 4 sessions), psychotherapy or counseling (15, defined as an interaction with a counselor longer than a brief intervention or that included a psychotherapeutic component), health promotion and education (20, defined as an intervention encouraged individuals’ agency of taking care of their health), or biologic treatments (19, defined as interventions where the biological function of alcohol use disorder (AUD) as the main nexus of intervention) with 3 mixing categories of intervention types. Due to high heterogeneity of intervention types, outcome measures, and follow-up times, we did not conduct meta-analysis to compare and contrast studies, but created a meta-summary of all 75 RCT studies. The most commonly evaluated intervention with the most consistent positive effect was a brief intervention; similarly, motivational interviewing (MI) techniques were most commonly utilized among the diverse array of interventions evaluated.ConclusionsOur review demonstrated numerous patient-level interventions that have the potential to be effective in LMICs, but further research to standardize interventions, populations, and outcome measures is necessary to accurately assess their effectiveness. Brief interventions and MI techniques were the most commonly evaluated and had the most consistent positive effect on alcohol-related outcomes.Trial registrationProtocol Registry: PROSPERO CRD42017055549

Catherine Staton and co-workers report on evidence about interventions against harmful alcohol use in low- and middle-income countries.  相似文献   
32.
Selected strains of three species of white rot fungi, Pleurotus ostreatus, Phanerochaete chrysosporium and Trametes versicolor, were grown in sterilized soil from straw inocula. The respective colonization rates and mycelium density values decreased in the above mentioned order. Three- and four-ringed PAHs at 50 ppm inhibited growth of fungi in soil to some extent. The activities of fungal MnP and laccase (units per g dry weight of straw or soil), extracted with 50 mM succinate-lactate buffer (pH 4.5), were 5 to 20-fold higher in straw compared to soil. The enzyme activities per g dry soil in P. ostreatus and T. versicolor were similar, in contrast to P. chrysosporium, where they were extremely low. Compared to the aerated controls, P. ostreatus strains reduced the levels of anthracene, pyrene and phenanthrene by 81–87%, 84–93% and 41–64% within 2 months, respectively. During degradation of anthracene, all P. ostreatus strains accumulated anthraquinone. PAH removal rates in P. chrysosporium and T. versicolor soil cultures were much lower.  相似文献   
33.
Isoamyl alcohol reduced growth and induced filament formation in Saccharomyces cerevisiae. Isoamyl alcohol-induced filamentation was accompanied by an almost threefold greater increase in the specific activity of succinate dehydrogenase than in untreated cells, which suggested that isoamyl alcohol treatment caused the cells to produce more mitochondria than in normal yeast form proliferation. This was supported by measuring the dry weight of purified, isolated mitochondria. Filaments have an increased chitin content which is distributed over the majority of their surface, and is not confined to bud scars and the chitin ring between mother and daughter cells as in yeast-form cells.  相似文献   
34.
Cytokinin-binding proteins (CBPs) isolated from mature grains of oat ( Avena sativa L.) and wheat ( Triticum aestivum L.) by acid precipitation, ion-exchange and affinity chromatography had similar characteristics, although they differed somewhat in apparent molecular weight of the native protein as determined by gel filtration (109 and 133 kDa, respectively) and subunit size as estimated by SDS-polyacrylamide gel electrophoresis (47 and 55 kDa, respectively). Highly purified oat CBP showed very weak but distinct immunochemical cross-reactivity with anti-wheat CBP IgG, indicating different immunogenic properties of the two CBPs. Nevertheless, both CBPs exhibited very similar binding of different cytokinins and were characterized by high affinity for N6-benzyladenine (BA)-type and by low affinity for zeatin-type cytokinins to both wheat and oat CBPs and by somewhat higher binding activities of oat CBP compared to wheat CBP (Kds for BA: 4.6 × 10−7  M and 6.8 × 10−7  M , respectively). The potential role of CBPs in regulating free BA-type cytokinin levels during cereal grain development and germination is discussed.  相似文献   
35.
Follicle-stimulating hormone, activin A, and transforming growth factor (TGF) alpha are important regulators of chicken granulosa cell (cGC) function. Hence, we aimed to test whether these growth factors are useful for establishing a suitable in vitro cell culture model system of primary cGC. Although cGC are easily isolated from distinct follicular stages, a long-term cGC culture system for in vitro studies has been unavailable. Here, we report a novel, long-term cell culture system that allows for cGC proliferation in vitro while maintaining the epithelial phenotype that granulosa cells exhibit in vivo. The cGC rapidly lose their epithelial morphology and acquire a mesenchymal or fibroblastoid phenotype when cultured in the absence of activin A. This process is strongly enhanced by TGFalpha, a well-known granulosa cell mitogen. However, FSH stimulates cGC proliferation without enhancing morphological changes and dedifferentiation. Interestingly, a combination of both activin A and FSH stimulates cGC proliferation and supports maintenance of differentiated epithelial morphology. Furthermore, activin A and FSH synergistically induce granulosa cell-specific differentiation markers such as inhibin alpha and chicken zona pellucida protein C, suggesting that cultured cGC resemble functionally differentiated granulosa cells. Our data demonstrate that activin signaling is necessary to sustain a morphologically differentiated phenotype of cGC in vitro. The results also suggest a pivotal importance of activin signaling for granulosa cell function in vivo.  相似文献   
36.
Total internal reflection excitation used in combination with fluorescence correlation spectroscopy (TIR-FCS) is a method for characterizing the dynamic behavior and absolute concentrations of fluorescent molecules near or at the interface of a planar substrate and a solution. In this work, we demonstrate for the first time the use of TIR-FCS for examining the interaction kinetics of fluorescent ligands in solution which specifically and reversibly associate with receptors in substrate-supported planar membranes. Fluorescence fluctuation autocorrelation functions were obtained for a fluorescently labeled IgG reversibly associating with the mouse receptor FcgammaRII, which was purified and reconstituted into substrate-supported planar membranes. Data were obtained as a function of the IgG solution concentration, the Fc receptor surface density, the observation area size, and the incident intensity. Best fits of the autocorrelation functions to appropriate theoretical forms gave measures of the average surface density of bound IgG, the local solution concentration of IgG, the kinetic rate constant for surface dissociation, and the rate of diffusion through the depth of the evanescent field. The average number of observed fluorescent molecules, both in solution and bound to the surface, scaled with the solution concentration of IgG, observation area size, and Fc receptor surface density as expected. The dissociation rate constant and rate of diffusion through the evanescent field agree with previous results, and all measured parameters were independent of the incident intensity.  相似文献   
37.
38.
39.
Petersson M  Lagumdzija A  Stark A  Bucht E 《Peptides》2002,23(6):1121-1126
Oxytocin receptors have recently been demonstrated in human osteoblast-like (hOB) cells. In this study, oxytocin 100-1000 pmol/l increased cell proliferation of primary cultures of hOB cells, measured by [3H]thymidine incorporation, (P<0.01). In human osteosarcoma cell-line (SaOS-2), oxytocin 100 pmol/l increased cell proliferation (measured by [3H]thymidine incorporation and a commercially available kit) and protein synthesis ([3H]proline incorporation) (P<0.05). The increase in cell proliferation was abolished when SaOS-2 cells were incubated with an oxytocin antagonist and oxytocin. Oxytocin 100 pmol/l decreased interleukin-6 (IL-6) production of the hOB cells (23.4+/-1.96 versus 33.4+/-2.65 pg/well; P<0.001). These findings indicate that oxytocin may affect bone metabolism in humans.  相似文献   
40.
UV skin exposure induces extensive generation of reactive oxygen species (ROS). These can react with DNA, proteins, fatty acids and saccharides causing oxidative damage. Such injuries result in a number of harmful effects: disturbed cell metabolism, morphological and ultrastructural changes, attack on the regulation pathways and, alterations in the differentiation, proliferation and apoptosis of skin cells. These processes can lead to photoaging and skin cancer development. One approach to protecting human skin against the harmful effects of UV irradiation is to use antioxidants as photoprotectives. In recent years naturally occurring herbal compounds such as phenolic acids, flavonoids, and high molecular weight polyphenols have gained considerable attention as beneficial protective agents. In this review, we strive to summarize the findings of studies performed to date, regarding the photoprotective effects of plant phenolics on the skin damage induced by UV radiation.  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