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   24292篇
  免费   1578篇
  国内免费   50篇
耳鼻咽喉   162篇
儿科学   776篇
妇产科学   809篇
基础医学   3025篇
口腔科学   345篇
临床医学   3849篇
内科学   4050篇
皮肤病学   228篇
神经病学   2530篇
特种医学   634篇
外科学   2189篇
综合类   280篇
一般理论   32篇
预防医学   3539篇
眼科学   363篇
药学   1458篇
中国医学   26篇
肿瘤学   1625篇
  2023年   148篇
  2022年   105篇
  2021年   405篇
  2020年   305篇
  2019年   466篇
  2018年   588篇
  2017年   436篇
  2016年   496篇
  2015年   601篇
  2014年   820篇
  2013年   1196篇
  2012年   1763篇
  2011年   1926篇
  2010年   1028篇
  2009年   902篇
  2008年   1656篇
  2007年   1788篇
  2006年   1669篇
  2005年   1681篇
  2004年   1638篇
  2003年   1490篇
  2002年   1464篇
  2001年   278篇
  2000年   207篇
  1999年   203篇
  1998年   258篇
  1997年   197篇
  1996年   157篇
  1995年   188篇
  1994年   167篇
  1993年   119篇
  1992年   146篇
  1991年   122篇
  1990年   93篇
  1989年   105篇
  1988年   92篇
  1987年   103篇
  1986年   73篇
  1985年   92篇
  1984年   72篇
  1983年   79篇
  1982年   85篇
  1981年   72篇
  1980年   49篇
  1979年   56篇
  1978年   36篇
  1977年   26篇
  1974年   25篇
  1973年   25篇
  1972年   27篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
1.
2.
3.
4.
5.
BackgroundGastric cancer (GC) is a leading cause of cancer-related death in the world and most patients have advanced disease upon presentation. The effect of age on prognosis in GC is controversial. We aimed to determine the impact of age on survival in patients with GC.MethodsThis was a retrospective study of the medical records of Lebanese patients diagnosed with GC at the American University of Beirut Medical Center (AUBMC) between 2005 and 2014. Patients were divided into young (<65 years) and older groups (≥65 years). A multivariate analysis was done to determine the independent predictors of survival. Kaplan-Meier method was used for analysis of long-term survival outcomes.ResultsThe sample consisted of 156 patients. The mean age was 62.15 (SD 13.54). Most patients presented with stage 4 disease (62.2%) and poorly differentiated histology (66.4%). The most common symptoms were abdominal pain and weight loss. On bivariate analysis, advanced stage (P=0.02) and higher grade (P=0.04) were associated with increased mortality. Patients <65 years of age were significantly more likely to have poorly differentiated tumours, while patients ≥65 years had more comorbidities (P=0.001). The 5-year DFS were 35% and 37% for patients <65 years of age and ≥65 years of age, respectively (P=0.15).ConclusionsHigher grade and advanced stage are associated with worse survival in patients with GC, but age did not seem to have an impact. Screening high risk patients and early diagnosis are necessary to improve survival.  相似文献   
6.
7.

Objective

Successful weight loss interventions for African-Americans adolescents are lacking. Cognitive-behavioral interventions seek to develop weight loss skills (e.g., counting calories, goal setting, managing one's environment). Little is known about how well adolescents implement such skills in their daily lives. Study aims were to (1) examine weight loss skills utilization at midpoint and end of a 6-month cognitive-behavioral/motivational interviewing weight loss sequential multiple assignment randomized trial (SMART), and (2) determine if greater skill utilization predicted weight loss at treatment end and 3 months post-treatment.

Method

One hundred and eighty six African-Americans adolescents with obesity and their caregiver were first randomly assigned to complete 3 months of cognitive-behavioral and motivational interviewing family-based weight loss treatment in their home or in the research office (Phase 1). Nonresponders (i.e., those who lost < 3% of initial weight, n?=?161) were rerandomized to 3 months of continued skills training (n?=?83) or contingency management (n?=?78) for Phase 2; responders were allocated to 3 months of relapse prevention (n?=?20). Adolescents’ frequency of weight loss skills utilization was assessed via questionnaire at treatment midpoint and end.

Results

Higher treatment attendance was associated with better skill utilization. Higher skill utilization was associated with more weight loss at treatment end, whereas higher baseline confidence was associated with more weight loss at follow-up.

Conclusions

This study indicates the importance of attending weight loss intervention sessions to develop and strengthen weight loss skills in African-American adolescents with obesity, and strengthening confidence to use such skills for continued weight loss.  相似文献   
8.

Objective

To evaluate the cost-effectiveness of financial incentives for human immunodeficiency virus (HIV) viral suppression compared to standard of care.

Study Design

Mathematical model of 2-year intervention offering financial incentives ($70 quarterly) for viral suppression (<400 copies/ml3) based on the HPTN 065 clinical trial with HIV patients in the Bronx, NY and Washington, D.C.

Methods

A disease progression model with HIV transmission risk equations was developed following guidelines from the Second Panel on Cost-Effectiveness in Health and Medicine. We used health care sector and societal perspectives, 3% discount rate, and lifetime horizon. Data sources included trial data (baseline N = 16,208 patients), CDC HIV Surveillance data, and published literature. Outcomes were costs (2017 USD), quality-adjusted life years (QALYs), HIV infections prevented, and incremental cost-effectiveness ratio (ICER).

Results

Financial incentives for viral suppression were estimated to be cost-saving from a societal perspective and cost-effective ($49,877/QALY) from a health care sector perspective. Compared to the standard of care, financial incentives gain 0.06 QALYs and lower discounted lifetime costs by $4210 per patient. The model estimates that incentivized patients transmit 9% fewer infections than the standard-of-care patients. In the sensitivity analysis, ICER 95% credible intervals ranged from cost-saving to $501,610/QALY with 72% of simulations being cost-effective using a $150,000/QALY threshold. Modeling results are limited by uncertainty in efficacy from the clinical trial.

Conclusions

Financial incentives, as used in HTPN 065, are estimated to improve quality and length of life, reduce HIV transmissions, and save money from a societal perspective. Financial incentives offer a promising option for enhancing the benefits of medication in the United States.  相似文献   
9.
10.
Although parenting behaviors are widely considered an important factor in the adjustment of children and adolescents with chronic physical health needs, few studies have addressed this topic as it pertains to youth with perinatally-acquired human immunodeficiency virus (PHIV). We examined profiles of child-centeredness, control through guilt, consistent discipline, and detachment, and whether these profiles differed in terms of parent- and youth-reported psychiatric disorder symptoms in a cohort of HIV infected youth (N?=?314). Latent profile analyses of caregiving behaviors were conducted separately for children (6–12 years) and adolescents (13–18 years). Two profiles were identified among children: (a) moderate caregiving (87%, n?=?130) and (b) high detachment caregiving (13%, n?=?19), and three profiles were identified among adolescents: (a) moderate caregiving (55%, n?=?88), (b) high detachment caregiving (19%, n?=?30), and (c) high control through guilt caregiving (26%, n?=?42). The high detachment and high control through guilt caregiving profiles displayed higher levels of parent-and youth-reported symptoms than the moderate caregiving profile. These findings suggest that caregiver behaviors of PHIV youth vary as a function of children’s developmental period and differ in terms of youth psychological symptoms.  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