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   4055篇
  免费   238篇
  国内免费   8篇
耳鼻咽喉   18篇
儿科学   193篇
妇产科学   77篇
基础医学   547篇
口腔科学   79篇
临床医学   269篇
内科学   771篇
皮肤病学   105篇
神经病学   272篇
特种医学   98篇
外科学   430篇
综合类   213篇
一般理论   1篇
预防医学   281篇
眼科学   61篇
药学   362篇
中国医学   17篇
肿瘤学   507篇
  2023年   20篇
  2022年   62篇
  2021年   144篇
  2020年   69篇
  2019年   64篇
  2018年   115篇
  2017年   74篇
  2016年   112篇
  2015年   116篇
  2014年   138篇
  2013年   195篇
  2012年   279篇
  2011年   285篇
  2010年   193篇
  2009年   133篇
  2008年   226篇
  2007年   210篇
  2006年   195篇
  2005年   164篇
  2004年   154篇
  2003年   149篇
  2002年   144篇
  2001年   117篇
  2000年   90篇
  1999年   84篇
  1998年   35篇
  1997年   27篇
  1996年   19篇
  1995年   27篇
  1994年   21篇
  1993年   27篇
  1992年   46篇
  1991年   48篇
  1990年   40篇
  1989年   30篇
  1988年   34篇
  1987年   25篇
  1986年   24篇
  1985年   24篇
  1984年   21篇
  1983年   25篇
  1979年   27篇
  1977年   17篇
  1976年   19篇
  1975年   15篇
  1974年   17篇
  1973年   16篇
  1972年   15篇
  1971年   16篇
  1968年   13篇
排序方式: 共有4301条查询结果,搜索用时 46 毫秒
81.
82.
83.
84.
85.
86.
The last decade has witnessed considerable interest in pathological conditions stemming from misuse or overuse of technology, a condition commonly referred to as technopathology. Of the several complaints reported, phantom vibration or phantom ringing is one that has not yet been widely explored. The objective of conducting a systematic review is to provide an understanding of the phenomena and summarize the research conducted so far. Major databases were searched and articles that matched the inclusion criteria were selected for final analysis. According to findings obtained, phantom vibration or phantom ringing was commonly experienced by mobile phone users; however, few found it bothersome and hence took no steps to eliminate it. As of now, literature in the area is limited and many aspects of the phenomena such as its prevalence across populations, causal factors, consequences, and treatment plans are yet to be studied. Also, a clinical criterion for identification of the condition needs to be formulated. With increase in the number of individuals reporting mobile phone‐related problem behavior, phantom vibration, or phantom ringing may be expected to become a cause of concern for mental health professionals within some years. Finally, the need for further research is emphasized while presenting directions for future investigations.  相似文献   
87.
88.

Background

Maternal alcohol exposure and adult alcohol intake have been shown to perturb the metabolism of various micro- and macro-nutrients, including vitamin A and its derivatives (retinoids). Therefore, it has been hypothesized that the well-known detrimental consequences of alcohol consumption may be due to deregulations of the metabolism of such nutrients rather than to a direct effect of alcohol. Alcohol exposure in utero also has long-term harmful consequences on the health of the offspring with mechanisms that have not been fully clarified. Disruption of tissue retinoid homeostasis has been linked not only to abnormal embryonic development, but also to various adult pathological conditions, including cancer, metabolic disorders and abnormal lung function. We hypothesized that prenatal alcohol exposure may permanently perturb tissue retinoid metabolism, predisposing the offspring to adult chronic diseases.

Methods

Serum and tissues (liver, lung and prostate from males; liver and lung from females) were collected from 60-75 day-old sprague dawley rats born from dams that were: (I) fed a liquid diet containing 6.7% alcohol between gestational day 7 and 21; or (II) pair-fed with isocaloric liquid diet during the same gestational window; or (III) fed ad libitum with regular rat chow diet throughout pregnancy. Serum and tissue retinoid levels were analyzed by reverse-phase high-performance liquid chromatography (HPLC). Serum retinol-binding protein (RBP) levels were measured by western blot analysis, and liver, lung and prostate mRNA levels of lecithin-retinol acyltransferase (LRAT) were measured by qPCR.

Results

Retinyl ester levels were significantly reduced in the lung of both males and females, as well as in the liver and ventral prostate of males born from alcohol-fed dams. Tissue LRAT mRNA levels remained unchanged upon maternal alcohol treatment.

Conclusions

Prenatal alcohol exposure in rats affects retinoid metabolism in adult life, in a tissue- and sex-dependent manner. We propose that the alcohol-induced perturbations of vitamin A metabolism may predispose to detrimental consequnces on adult health.  相似文献   
89.
India is considered to have a low incidence of HIV infection so far. Nevertheless, an epidemic of HIV infection has been reported recently among intra-venous drug users (IVDUs) in Manipur, a north-eastern state of India, bordering Myanmar (Burma). This report describes the epidemiology of intravenous drug abuse in the state of Manipur. Four hundred and fifty IVDUs were interviewed. Their age (median 24 years) and sex patterns (95% male) differ from those reported from western countries. It is estimated that there may be approximately 15,000 such addicts in a population of 1.8 million and 50% of them could be positive for HIV. Knowledge of AIDS and its transmission is significantly higher among the addicts than non-addict controls. Free availability of heroin was found to be the major factor responsible for the high rate of addiction. It is presumed that two other neighbouring States which are well-connected to Manipur and also have a common border with Myanmar (part of the 'Golden Triangle') may have a similar problem with HIV infection.  相似文献   
90.
Alcohol consumption is increasing in the United States, as is alcohol‐attributable mortality. Historically, men have had higher rates of alcohol consumption than women, though evidence for birth cohort effects on gender differences in alcohol consumption and alcohol‐related harm suggests that gender differences may be diminishing. We review studies using U.S. national data that examined time trends in alcohol consumption and alcohol‐related harm since 2008. Utilizing a historical–developmental perspective, here we synthesize and integrate the literature on birth cohort effects from varying developmental periods (i.e., adolescence, young adulthood, middle adulthood, and late adulthood), with a focus on gender differences in alcohol consumption. Findings suggest that recent trends in gender differences in alcohol outcomes are heterogeneous by developmental stage. Among adolescents and young adults, both males and females are rapidly decreasing alcohol consumption, binge and high‐intensity drinking, and alcohol‐related outcomes, with gender rates converging because males are decreasing consumption faster than females. This pattern does not hold among adults, however. In middle adulthood, consumption, binge drinking, and alcohol‐related harms are increasing, driven largely by increases among women in their 30s and 40s. The trend of increases in consumption that are faster for women than for men appears to continue into older adult years (60 and older) across several studies. We conclude by addressing remaining gaps in the literature and offering directions for future research.  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