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   2395篇
  免费   213篇
  国内免费   2篇
耳鼻咽喉   33篇
儿科学   62篇
妇产科学   30篇
基础医学   341篇
口腔科学   37篇
临床医学   309篇
内科学   496篇
皮肤病学   11篇
神经病学   175篇
特种医学   36篇
外科学   309篇
综合类   93篇
一般理论   1篇
预防医学   195篇
眼科学   72篇
药学   99篇
中国医学   2篇
肿瘤学   309篇
  2021年   37篇
  2019年   36篇
  2018年   41篇
  2017年   23篇
  2016年   24篇
  2015年   36篇
  2014年   47篇
  2013年   105篇
  2012年   112篇
  2011年   99篇
  2010年   61篇
  2009年   66篇
  2008年   130篇
  2007年   125篇
  2006年   131篇
  2005年   108篇
  2004年   107篇
  2003年   107篇
  2002年   110篇
  2001年   36篇
  2000年   39篇
  1999年   49篇
  1998年   29篇
  1996年   22篇
  1995年   24篇
  1994年   22篇
  1992年   25篇
  1991年   30篇
  1990年   27篇
  1989年   34篇
  1988年   24篇
  1987年   27篇
  1985年   26篇
  1984年   34篇
  1983年   25篇
  1982年   41篇
  1981年   23篇
  1980年   28篇
  1979年   29篇
  1978年   31篇
  1977年   26篇
  1976年   22篇
  1975年   21篇
  1974年   30篇
  1973年   25篇
  1972年   23篇
  1971年   26篇
  1970年   27篇
  1969年   21篇
  1967年   21篇
排序方式: 共有2610条查询结果,搜索用时 687 毫秒
1.
2.
3.
4.
汽车机械学 Bobby是我的汽车修理师,他有一种我喜欢效仿的工作风格。首先他是一位伟大的诊断专家;如果你告诉他汽车出现了什么问题,他会帮你做出鉴别诊断。“运货车是否发动不着了?发动机是否转动?你是否听到了滴滴答答的声音?”问了几个问题后,他便会做出判断。比如我的发动机供不上汽油了,排除了几种可能性后他认为是由燃油泵造成的。  相似文献   
5.
6.
The Effect of Cuts in Medicare Reimbursement on Hospital Mortality   总被引:1,自引:0,他引:1  
Objective. To determine if patients treated at hospitals under different levels of financial strain from the Balanced Budget Act (BBA) of 1997 had differential changes in 30-day mortality, and whether vulnerable patient populations such as the uninsured were disproportionately affected.
Data Source. Hospital discharge data from all general acute care hospitals in Pennsylvania from 1997 to 2001.
Study Design. A multivariate regression analysis was performed retrospectively on 30-day mortality rates, using hospital discharge data, hospital financial data, and death certificate information from Pennsylvania.
Data Collection. We used 370,017 hospital episodes with one of four conditions identified by the Agency for Healthcare Research and Quality as inpatient quality indicators were extracted.
Principal Findings. The average magnitude of Medicare payment reduction on overall net revenues was estimated at 1.8 percent for hospitals with low BBA impact and 3.6 percent for hospitals with a high impact in 1998, worsening to 2 and 4.8 percent, respectively, by 2001. Operating margins decreased significantly over the time period for all hospitals ( p <.05). While unadjusted mortality rates demonstrated a disproportionate rise in mortality for patients from high impact hospitals from 1997 to 2000, adjusted analyses show no consistent, significant difference in the rate of change in mortality between high-impact and low-impact hospitals ( p =.04–.94). Similarly, uninsured patients did not experience greater increases in mortality in high-impact hospitals relative to low-impact hospitals.
Conclusions. An analysis of hospitalizations in the Commonwealth of Pennsylvania did not find an adverse impact of increased financial strain from the BBA on patient mortality either among all patients or among the uninsured.  相似文献   
7.
The correct identification of syndromes and other congenital malformations at an early age is critical for the child, family and care providers. Most specialists who conduct large screenings of young children are not adequately trained to recognize signs and symptoms that should lead to appropriate referral to the clinical geneticist and/or diagnostic team. A systematic approach for recognizing important signs is presented here; a Craniofacial Screening Profile. Following a brief training program, the Profile was validated by 39 speech-language pathologists in screening 3,539 kindergarten and first grade children. The results were excellent (specificity was 99.6%), demonstrating that with limited training, specialists can effectively screen for important signs and symptoms of a major group of syndromes and other congenital malformations.  相似文献   
8.
我的病人莎拉来就诊的主诉是呼吸困难,不过体检时除了有一点呼气时喘息,没有明显的其他症状,也没有发热,我还是先给她拍了个X线胸片。  相似文献   
9.
The hypercatabolism after massive pediatric burns has been effectively treated with recombinant human growth hormone, an anabolic agent that stimulates protein synthesis and abrogates growth arrest. While experimental studies have shown increased potential for fibrosis induced by growth hormone therapy, adverse effects on human scars have not been investigated. Our aim was to evaluate hypertrophic scar formation in 62 patients randomized to receive injections of 0.05 mg/kg/day of recombinant human growth hormone or placebo, from discharge until 1 year after burn. Scar scales were used to evaluate scar-severity at discharge, 6, 9, 12, and 18-24 months after burn, by three observers blinded to treatment. Computer-assisted planimetry allowed quantification of percentage of hypertrophic scar formation. Types I and III collagens were localized and quantified in scars and normal skin of patients from both groups, using immunohistochemistry with confocal laser microscopy analysis. Insulin-like growth factor-1 blood levels helped assess compliance. Statistical analysis showed that scar hypertrophy significantly increased from 6 to 12 months after injury in both groups, while decreasing at 18-24 months postburn. Types I and III collagens were statistically increased in the reticular layer of scars from both groups when compared to paired normal skin. Insulin-like growth factor-1 was significantly increased in the recombinant human growth factor-treated group. No differences were seen when recombinant human growth factor and control groups were compared using the scar scales, planimetry, or immunohistochemistry. We concluded that recombinant human growth hormone therapy did not adversely affect scar formation and should not contraindicate the administration of recombinant human growth hormone as a therapeutic approach to severely burned children.  相似文献   
10.
A commercially available ADAC Pinnacle(3) radiation treatment planning system has been used to model electron beams from a Varian Clinac 2300C/D in the energy range of 6 to 22 MeV. Prior to clinical use, the dosimetric characteristics of the beams have to be modeled accurately. As a first step for beam modeling, a number of dose profile and depth dose measurements were taken at standard source-to-surface distance (SSD) of 100 cm. Dose profiles and depth dose measurements at extended SSDs up to 120 cm are important for ascertaining accuracy of the model, as well as their clinical usefulness in the treatment of some sites (e.g., head-and-neck tumors). Modeled and measured beam data were compared. Over 98% of comparison points (modeled vs. measured) at 100-cm SSD were within 2.5% or 2.5 mm. At 110 cm SSD, over 98% of compared points were within 4% or 4 mm, and at 120-cm SSD, over 98% of compared points were within 5% or 5 mm. Overall, more than 98% of compared points were within 4% or 4 mm. Better models were produced for lower energies (6 to 15 MeV) than higher energies (18 and 22 MeV). For 6, 9, 12, and 15 MeV, 89% of compared points were within 2% or 2 mm. For 18- and 22-MeV electron energies, 75% and 67%, respectively, were within 2% or 2 mm. These results are consistent with the recommendations of AAPM Task Group Report 53.  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