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   10758篇
  免费   728篇
  国内免费   24篇
耳鼻咽喉   124篇
儿科学   271篇
妇产科学   171篇
基础医学   1463篇
口腔科学   348篇
临床医学   1437篇
内科学   1828篇
皮肤病学   85篇
神经病学   957篇
特种医学   357篇
外科学   1094篇
综合类   160篇
一般理论   8篇
预防医学   1276篇
眼科学   309篇
药学   782篇
中国医学   11篇
肿瘤学   829篇
  2023年   34篇
  2022年   65篇
  2021年   112篇
  2020年   99篇
  2019年   170篇
  2018年   156篇
  2017年   137篇
  2016年   170篇
  2015年   207篇
  2014年   255篇
  2013年   453篇
  2012年   649篇
  2011年   760篇
  2010年   379篇
  2009年   377篇
  2008年   664篇
  2007年   740篇
  2006年   763篇
  2005年   752篇
  2004年   679篇
  2003年   644篇
  2002年   672篇
  2001年   155篇
  2000年   109篇
  1999年   133篇
  1998年   136篇
  1997年   138篇
  1996年   93篇
  1995年   93篇
  1994年   78篇
  1993年   85篇
  1992年   89篇
  1991年   113篇
  1990年   89篇
  1989年   98篇
  1988年   75篇
  1987年   68篇
  1986年   66篇
  1985年   72篇
  1984年   67篇
  1983年   79篇
  1982年   78篇
  1981年   80篇
  1980年   67篇
  1979年   54篇
  1978年   40篇
  1977年   46篇
  1976年   45篇
  1974年   41篇
  1972年   36篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
This paper describes an innovative approach to preparing high school students with mild disabilities for challenging careers in high tech industries, called High School High Tech (HSHT). Iowa's HSHT Goes to College program has three central elements, each of which is discussed in this paper: High School Preparation—assisting students in identifying a suitable high tech career goal; Higher Education Preparation and Supports—assisting students in selecting college/training programs that match their career goal, and in successfully completing their postsecondary programs; Workforce Entry Assistance—linking students with employers and launching their high tech careers. The paper concludes with a presentation of outcomes to date and recommendations for program enhancements. The information presented here is intended to assist education and rehabilitation professionals interested in establishing similar efforts across the nation.  相似文献   
14.
15.
BACKGROUND: The demand for renal replacement therapy (RRT) in England has risen steadily, although from a lower base than many other developed countries. Predicting the future demand for RRT and the impact of factors such as the acceptance rate, transplant supply and patient survival, is required in order to inform the planning of such services. METHODS: A discrete event simulation model estimates the future demand for RRT in England in 2010 for a range of scenarios. The model uses current prevalence and current and projected future acceptance rates, survival rates and the transitions between modalities to predict future patient numbers. National population and mortality data, published literature and data from the UK Renal Registry and UK Transplant, are used to estimate unmet need for RRT, the impact of changing demography and incidence of Type 2 diabetes, patient haemodialysis (HD) survival and transplant supply. RESULTS: By 2010 the predicted prevalence will have increased from about 30,000 in 2000 to between 42 and 51,000 (900-1000 p.m.p.), an average annual growth of 4.5-6%. Changing transplant supply has a small effect on overall numbers but changes the proportion of patients with functioning graft by up to 8%. Even with an optimistic increase in transplant supply (11% p.a. for 5 years), numbers on HD will continue to rise substantially, especially in the elderly. The factors most influencing future patient numbers are the acceptance rate and dialysis survival. CONCLUSION: This model predicts a substantial growth in the RRT population to 2010 to a rate approaching 1000 p.m.p., particularly in the elderly and those on HD, with a steady state not being reached for at least 25 years.  相似文献   
16.
Monoclonal antibodies against human and bovine 2′:3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) were generated by fusing FOX-NY myeloma cells with spleen cells from RBF/Dn mice previously immunized with the purified brain antigens. The enzyme isolated from bovine brain was quite basic, with an isoelectric point of 9.71 and both the bovine and human enzymes consisted of a closely spaced doublet at approximately 44 and 46 kDa on SDS-PAGE. Six monoclonals were identified as strongly recognizing the enzyme on both ELISA plates and on immunoblots of whole brain protein. Four monoclonals very weakly cross-reacted with guinea pig myelin basic protein. In contrast with two previous reports, some of our monoclonal antibodies did immunostain 2 or 3 protein bands in peripheral nerve, two bands closely corresponding to those immunostained in central nervous system (CNS) myelin, the Wolfgram protein fraction and in acetone powders of whole brain. Each of the 6 monoclonals reacting strongly on immunoblots recognized the enzyme in from 2 to 5 of the species examined (human, bovine, rat, mouse and rabbit). In addition, all 6 monoclonals that immunostained the enzyme in whole brain, myelin and Wolfgram protein immunoblots recognized both CNP1 (44 kDa) and CNP2 (46 kDa). The two closely spaced protein bands observed on SDS-PAGE and previously stained on immunoblots of CNS CNPase using polyvalent rabbit anti-bovine CNPase antisera, and now different monoclonal antibodies, appear to be immunologically related and to contain highly conserved sequences.  相似文献   
17.
18.
1. Plasma potassium and chloride concentrations were raised and plasma renin activity, aldosterone, bicarbonate and arterial pH were reduced in two brothers with the syndrome of hypertension and hyperkalaemia with normal glomerular filtration rate (Gordon's syndrome), on unrestricted or moderately restricted sodium diets. 2. These abnormalities were corrected in both patients within 10 days of severe sodium restriction. 3. Pressor sensitivity to cold and angiotensin II decreased on low sodium diet, associated with a fall in blood pressure. 4. Increasing distal tubular sodium delivery by infusion of normal saline increased fractional excretion of potassium when aldosterone had been stimulated by severely restricted sodium diet, but not when aldosterone levels were low on unrestricted sodium diet. 5. These findings are consistent with excessive sodium reabsorption as the primary renal lesion in Gordon's syndrome, leading to volume expansion and suppression of renin and aldosterone. Severe dietary sodium restriction leading to volume contraction, by stimulating renin and aldosterone and promoting kaliuresis, corrects the abnormalities.  相似文献   
19.
20.
Exercise is associated with a reduced risk of coronary heart disease, has beneficial effects on cardiovascular risk factors, and has other health benefits. No more than 10 per cent to 20 per cent of adults in Australia and other developed countries participate in regular vigorous physical activity, while over 65 per cent of Australian adults are almost totally sedentary. Survey data from the U.S.A. suggest that levels of participation in jogging and walking have increased in the past 10 years but that the proportion of people who take no deliberate exercise has also increased. Large-scale community interventions to promote exercising have not been subject to rigorous evaluation and it is difficult to reach any firm conclusions about the effects of exercise promotion. However, it is possible to identify some of the factors which may influence exercise participation, and there is information from trials of large-scale, multifactorial interventions to reduce cardiovascular risk which provides some helpful guidelines about how it may be useful to proceed. Approaches to increasing levels of exercise participation should emphasise community-based efforts which provide appropriate settings and social support for exercising, making exercise a more appealing and accessible option for large numbers of people; the use of mass media for community education about exercising should be co-ordinated carefully with specific community activities. Personalized fitness instruction, groups and classes should place more emphasis on exercise as a pattern of behaviour to be integrated into a person's way of life and maintained over time; and there is the potential for more widespread and systematic use of self-instructional exercise materials to assist people who wish to exercise independently. Because there exist only limited local research findings and work in other countries does not yet provide conclusive information, research and development priorities for these areas are suggested.  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