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   1082篇
  免费   69篇
  国内免费   1篇
耳鼻咽喉   10篇
儿科学   21篇
妇产科学   13篇
基础医学   177篇
口腔科学   18篇
临床医学   87篇
内科学   154篇
皮肤病学   4篇
神经病学   111篇
特种医学   200篇
外科学   98篇
综合类   4篇
预防医学   50篇
眼科学   20篇
药学   61篇
中国医学   2篇
肿瘤学   122篇
  2021年   11篇
  2020年   10篇
  2019年   13篇
  2018年   14篇
  2017年   9篇
  2016年   32篇
  2015年   18篇
  2014年   29篇
  2013年   37篇
  2012年   37篇
  2011年   45篇
  2010年   28篇
  2009年   35篇
  2008年   35篇
  2007年   58篇
  2006年   57篇
  2005年   49篇
  2004年   43篇
  2003年   28篇
  2002年   25篇
  2001年   35篇
  2000年   19篇
  1999年   23篇
  1998年   23篇
  1997年   20篇
  1996年   14篇
  1995年   8篇
  1994年   13篇
  1992年   7篇
  1991年   9篇
  1990年   11篇
  1989年   23篇
  1988年   19篇
  1987年   20篇
  1986年   18篇
  1985年   23篇
  1984年   8篇
  1983年   11篇
  1978年   7篇
  1976年   7篇
  1975年   9篇
  1971年   7篇
  1939年   9篇
  1938年   8篇
  1935年   27篇
  1934年   8篇
  1933年   28篇
  1932年   18篇
  1931年   16篇
  1930年   7篇
排序方式: 共有1152条查询结果,搜索用时 15 毫秒
1.
Objective: Asthma disproportionately impacts and has poorer outcomes in low-income, minority, and inner-city children. The home environment has a profound impact on a child's asthma. Home-based asthma visits have the potential to positively impact a child's asthma, especially in targeted populations. The purpose of this integrative review is 1.) to explore the effectiveness of home-based education and environmental measures and 2.) to explore specific indicators and tools to measure pediatric asthma control and program effectiveness. Data Sources: Medline, CINHAL, and Ovid databases were searched from 2010 to 2017 utilizing the keywords healthy homes AND asthma and home based interventions AND asthma. Study Selections: A total of 71 articles were retrieved of which 27 articles met the inclusion criteria of English language, human subjects, and the inclusion of pediatric populations. Three additional articles were hand-searched from previous references. In total, 30 articles were reviewed. A quality appraisal was conducted utilizing standardized appraisal tools. Results: Home-based asthma education and environmental interventions have proven to be effective. The programs reviewed varied in types of interventions, intensity and duration, the type of provider, length of follow-up, and outcome measures. Successful programs were patient-centered, included a home assessment and individualized education and interventions, and were collaborative. Multiple outcome indicators such as health care utilization, asthma control, missed days of school or productivity, asthma symptoms, and verification of environmental remediation have been utilized. Conclusion: Home-based asthma programs can be beneficial to children with poorly controlled asthma and have the potential to be cost-effective.  相似文献   
2.
3.
4.
CASE REPORT: The reported female patient underwent sub-total resection of an intra-medullary cervicothoracic astrocytoma classified as WHO grade II in 1984 at the age of 18 months and received local irradiation. In 1989, a local recurrence was diagnosed and a partial resection was performed. Sixteen years later, a small recurrent cervicothoracic tumour was found and spinal seeding to the equine nerve roots and the left cerebellar cortex was apparent on MRI. The patient was implanted with a ventriculoperitoneal shunt for a pseudo-tumour cerebri producing papilloedema, which eventually lead to amaurosis. After an extended biopsy, the invasive lumbosacral tumour was classified as glioblastoma multiforme. Two months later, the patient died after rapid progression of the caudal cranial nerve dysfunction. DISCUSSION AND CONCLUSION: Anaplastic progression and dissemination of spinal astrocytomas even two decades after initial diagnosis and treatment are rare. Therapies and diagnostic follow-up strategies are discussed.  相似文献   
5.
6.
Using Rbp4-null mice as models, we have established for the first time the kinetics of the spermatogenetic alterations during vitamin A deficiency (VAD). Our data demonstrate that the VAD-induced testicular degeneration arises through the normal maturation of germ cells in a context of spermatogonia differentiation arrest. They indicate that retinoic acid (RA) appears dispensable for the transition of premeiotic to meiotic spermatocytes, meiosis, and spermiogenesis. They confirm that RA plays critical roles in controlling spermatogonia differentiation, spermatid adhesion to Sertoli cells, and spermiation, and suggest that the VAD-induced arrest of spermatogonia differentiation results from simultaneous blocks in RA-dependent events mediated by RA receptor gamma (RARgamma) in spermatogonia and by RARalpha in Sertoli cells. They also provide evidence that expression of major RA-metabolizing enzymes is increased in mouse Sertoli cells upon VAD and that vitamin A-deficient A spermatogonia differ from their RA-sufficient counterparts by the expression of the Stra8 gene.  相似文献   
7.
8.
9.
This paper describes the tragic case of a young woman who died of cancer of the colon after successfully donating eggs to her younger sister. Although there is no direct link between her operation and the subsequent development of bowel carcinoma, this case imparts a feeling of unease when seen in conjunction with other cases reported during the last few years. It is a reminder that little is known of the long-term consequences of some aspects of assisted conception. Women undergoing ovarian stimulation for themselves or a matched recipient have the right to be advised, in an agreed format, that there is some concern about unproven potential risks from the stimulatory drugs. The safety of egg donors must assume priority over all other considerations, including lack of donors or any moral position. The recent decision by the Human Fertilisation and Embryology Authority (HFEA) to withdraw any form of payment or recompense to egg donors does not seem to us to be based on a balance of scientific advances, patient needs and the ethics of gamete supply. They state that the intention to withdraw payments was implicit in the 1990 Human Fertilisation and Embryology (HFE) Act. However the Act was based on the Warnock report made 6 years earlier. Even in 1990 ovum donation was uncommon and fertility drugs had not yet caused any unease. The Act provided the HFEA with discretionary powers to issue directions so that the future policies would be consistent with any emerging new medical evidence. It is imperative that the HFEA provide convincing evidence on how the current policy of payment to donors harms society, donors or recipients, and how in the UK the new policy will improve medical practice in assisted conception. Successful pilot studies must precede the implementation of any new policy. Failure to do this could cause irreversible harm to the practice of assisted conception using donor gametes, which will ultimately be against the basic aims of the 1990 HFE Act.   相似文献   
10.
Neuronal Cell Death in Scrapie-Infected Mice Is Due to Apoptosis   总被引:3,自引:0,他引:3  
Neuronal loss is a salient yet poorly understood feature in the pathology of transmissible spongiform encephalopathies (prion diseases). Cell culture experiments with neurotoxic prion protein fragments suggest that neuronal cell death in these diseases may be due to apoptosis. To test this hypothesis in vivo we used the in situ end-labeling (ISEL) technique and electron microscopy to study cell death in an experimental scrapie system in the mouse. ISEL, which relies on the incorporation of labeled nucleotides in fragmented DNA by terminal transferase, showed labeled nuclei in the brains and retinae of mice infected with the 79A strain of scrapie, whereas no labeling was observed in control animals. In the retina the highest numbers of labeled nuclei were found in the outer nuclear layer 120 days post infection followed by massive cell loss in this layer. In the brain, labeled nuclei were mainly found in the granular layer of the cerebellum of terminally ill mice. This corresponded to the presence of small dark nuclei with condensed and occasionally fragmented chromatin at the light and electron microscopical levels. Our results support the hypothesis that neuronal loss in spongiform encephalopathies is due to apoptosis. This may explain the almost complete absence of inflammatory response in prion diseases in the face of widespread neuronal cell death, and may also have therapeutic implications in the future.  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