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   492篇
  免费   20篇
  2022年   6篇
  2021年   14篇
  2020年   5篇
  2019年   4篇
  2018年   2篇
  2017年   2篇
  2016年   11篇
  2015年   14篇
  2014年   23篇
  2013年   23篇
  2012年   30篇
  2011年   39篇
  2010年   14篇
  2009年   17篇
  2008年   22篇
  2007年   24篇
  2006年   18篇
  2005年   20篇
  2004年   13篇
  2003年   16篇
  2002年   10篇
  2001年   11篇
  2000年   18篇
  1999年   10篇
  1998年   8篇
  1997年   10篇
  1996年   7篇
  1995年   5篇
  1994年   3篇
  1993年   4篇
  1992年   14篇
  1991年   7篇
  1990年   5篇
  1989年   9篇
  1988年   8篇
  1987年   7篇
  1986年   2篇
  1985年   4篇
  1984年   3篇
  1983年   5篇
  1981年   6篇
  1980年   6篇
  1979年   4篇
  1978年   2篇
  1975年   2篇
  1974年   2篇
  1973年   4篇
  1972年   6篇
  1969年   3篇
  1965年   2篇
排序方式: 共有512条查询结果,搜索用时 218 毫秒
501.
502.
503.
504.
505.
506.
Co-expression of cytokeratin (CK) pairs has been found to be associated with specific epithelial cell types whose expressions are developmentally regulated. In the prostate, CK 8 and 18 have been identified as luminal cell-specific markers, and CK 5 and 15 have been identified as basal cell-specific markers. In this study, we report the cloning and sequencing of a full-length CK 8 cDNA (1.9 kilobases) from a rat ventral prostate (VP) cDNA library. Although the open reading frame shares 90% homology with mouse CK 8 sequences, nucleotide comparison revealed that rat CK 8 cDNA comprises a species-specific sequence on both 5' and 3' ends. The steady-state levels of CK 8 mRNA were elevated in VP, seminal vesicle (SV), and liver of a castrated rat but not in the other organs such as the coagulating gland, bladder, and thymus. Unlike the other androgen-repressed genes, elevated CK 8 mRNA levels persisted even after the glandular involution was completed, indicating that CK 8 is a new class of androgen-repressed gene. The regression of CK 8 expression may be androgen receptor-mediated, since androgen but not estrogen administration to castrated hosts repressed the CK 8 mRNA levels, and this effect can be antagonized by the simultaneous administration of an antiandrogen (4-hydroxyflutamide). Immunohistochemical staining of prostatic tissues reveals that the CK 8 filamentous structure is shifted reversibly from a uniform distribution to a predominantly basal surface upon androgen deprivation. We noted that the steady-state levels of CK 8 protein remain rather constant throughout the various hormonal treatment, and the steady-state levels of CK 8 mRNA and the rate of CK 8 protein synthesis are consistently elevated. These results suggest that the turnover rate of CK 8 protein may be elevated in the prostatic epithelium from the castrated host. Similarly, the steady-state levels of CK 15 and 18 mRNA in VP and SV are also repressed in an androgen-dependent manner. These data, taken together, indicate that pairwise control of luminal (and possibly basal) specific cytokeratin gene expression remains intact in both VP and SV tissues and that the levels of CK mRNAs expression are negatively regulated by androgen.  相似文献   
507.
ObjectiveSodium-glucose cotransporter 2 inhibitors have been shown to reduce cardiovascular events but are currently not used as the first-line therapy. This study was conducted to evaluate the cost-effectiveness of first-line empagliflozin plus metformin versus metformin monotherapy among Australians with type 2 diabetes mellitus (T2DM) and existing cardiovascular disease (CVD).MethodsA Markov model with 1-year cycles and a 5-year time horizon was constructed to simulate the occurrence of recurrent cardiovascular events among Australians aged 50 to 84 years with T2DM and CVD. Efficacy results were derived from the Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients-Removing Excess Glucose trial. Costs and utilities were drawn from published sources. The evaluation adopted both health care and societal perspectives, with the latter ascribing the Australian government’s “value of statistical life year” (A$213 000) to each year lived by a person. Future outcomes were discounted at 5% annually. Sensitivity analyses were conducted to enhance the robustness of conclusions.ResultsCompared with metformin monotherapy, first-line empagliflozin plus metformin reduced overall cardiovascular events by 0.82% and overall deaths by 7.72% over 5 years. There were 0.2 years of life saved per person and 0.16 quality-adjusted life years gained, at a net health care cost of A$4408. These equated to incremental cost-effectiveness ratios of A$22 076 per year of life saved and A$28 244 per quality-adjusted life year gained. The gains in the value of statistical life year equated to A$42 530 per person, meaning that from a societal perspective, the intervention was cost-saving.ConclusionFirst-line empagliflozin plus metformin may represent a cost-effective strategy for the management of T2DM and CVD in Australia.  相似文献   
508.

Background  

Periodogram analysis of time-series is widespread in biology. A new challenge for analyzing the microarray time series data is to identify genes that are periodically expressed. Such challenge occurs due to the fact that the observed time series usually exhibit non-idealities, such as noise, short length, and unevenly sampled time points. Most methods used in the literature operate on evenly sampled time series and are not suitable for unevenly sampled time series.  相似文献   
509.
BackgroundStreptoccocus suis (S.suis) infection is a neglected zoonosis disease in humans mainly affects men of working age. We estimated the health and economic burden of S.suis infection in Thailand in terms of years of life lost, quality-adjusted life years (QALYs) lost, and productivity-adjusted life years (PALYs) lost which is a novel measure that adjusts years of life lived for productivity loss attributable to disease.MethodsA decision-analytic Markov model was developed to simulate the impact of S. suis infection and its major complications: death, meningitis and infective endocarditis among Thai people in 2019 with starting age of 51 years. Transition probabilities, and inputs pertaining to costs, utilities and productivity impairment associated with long-term complications were derived from published sources. A lifetime time horizon with follow-up until death or age 100 years was adopted. The simulation was repeated assuming that the cohort had not been infected with S.suis. The differences between the two set of model outputs in years of life, QALYs, and PALYs lived reflected the impact of S.suis infection. An annual discount rate of 3% was applied to both costs and outcomes. One-way sensitivity analyses and Monte Carlo simulation modeling technique using 10,000 iterations were performed to assess the impact of uncertainty in the model.Key resultsThis cohort incurred 769 (95% uncertainty interval [UI]: 695 to 841) years of life lost (14% of predicted years of life lived if infection had not occurred), 826 (95% UI: 588 to 1,098) QALYs lost (21%) and 793 (95%UI: 717 to 867) PALYs (15%) lost. These equated to an average of 2.46 years of life, 2.64 QALYs and 2.54 PALYs lost per person. The loss in PALYs was associated with a loss of 346 (95% UI: 240 to 461) million Thai baht (US$11.3 million) in GDP, which equated to 1.1 million Thai baht (US$ 36,033) lost per person.ConclusionsS.suis infection imposes a significant economic burden both in terms of health and productivity. Further research to investigate the effectiveness of public health awareness programs and disease control interventions should be mandated to provide a clearer picture for decision making in public health strategies and resource allocations.  相似文献   
510.
Two important challenges in microplate instrumentation are to achieve full well sample coverage and complete mixing. An effective approach of using superhydrophobic rods to accomplish these challenges is reported here. Experiments conducted showed that analytes above 50μl could be made to completely cover the bottom of 96-well standard and transparency microplates. Complete mixing was accomplished by moving the rod parallel to the well bottom while contacting the liquid. The approach is simple and controlled, and it minimizes the problems of spillage and cross-contamination. It works with analytes with varied volumes and of different viscosities present in each well of the microplate.  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