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   704666篇
  免费   49954篇
  国内免费   1297篇
耳鼻咽喉   9174篇
儿科学   23263篇
妇产科学   17608篇
基础医学   110433篇
口腔科学   19955篇
临床医学   63693篇
内科学   134224篇
皮肤病学   16166篇
神经病学   49473篇
特种医学   25740篇
外国民族医学   76篇
外科学   104529篇
综合类   14811篇
现状与发展   2篇
一般理论   160篇
预防医学   51353篇
眼科学   16307篇
药学   53945篇
  3篇
中国医学   2365篇
肿瘤学   42637篇
  2019年   5444篇
  2018年   7879篇
  2017年   6112篇
  2016年   6829篇
  2015年   7559篇
  2014年   10268篇
  2013年   15401篇
  2012年   20504篇
  2011年   21519篇
  2010年   12734篇
  2009年   11940篇
  2008年   20007篇
  2007年   21517篇
  2006年   21913篇
  2005年   20455篇
  2004年   19996篇
  2003年   18968篇
  2002年   18464篇
  2001年   36334篇
  2000年   36910篇
  1999年   30392篇
  1998年   7879篇
  1997年   6667篇
  1996年   6969篇
  1995年   6629篇
  1994年   6096篇
  1993年   5590篇
  1992年   22983篇
  1991年   22935篇
  1990年   22315篇
  1989年   22080篇
  1988年   20041篇
  1987年   19423篇
  1986年   18476篇
  1985年   17310篇
  1984年   12701篇
  1983年   10748篇
  1982年   5924篇
  1979年   11523篇
  1978年   8130篇
  1977年   6832篇
  1976年   6594篇
  1975年   7269篇
  1974年   8500篇
  1973年   8143篇
  1972年   7658篇
  1971年   7127篇
  1970年   6877篇
  1969年   6309篇
  1968年   5780篇
排序方式: 共有10000条查询结果,搜索用时 812 毫秒
991.
992.
BACKGROUND: Platelet hyperfunction contributes to acute coronary syndromes (ACS). Thus, we hypothesized that platelet function under high shear stress predicts recurrent ACS during long-term follow-up of ACS patients. PATIENTS AND METHODS: Consecutive ACS patients (n = 208) were prospectively followed-up for an average of 28 months. Platelet function was measured with the platelet function analyzer (PFA-100; Dade Behring, Marburg, Germany) at baseline for collagen/adenosine diphosphate closure times (CADP-CT) and for collagen/epinephrine closure times (CEPI-CT) after infusion of a uniform dose of 250 mg aspirin. RESULTS: Of the conventional risk factors, only the prevalence of diabetes was higher in ACS patients with re-events. However, use of clopidogrel and use of beta blockers were also slightly lower in patients with re-events (P < 0.05). The unadjusted risk hazard ratio (HR) for re-events was 3.3 [95% confidence interval (95% CI): 1.4-7.4; P = 0.005] in those patients with the shortest CADP-CT values (lowest quartile). Similarly, the risk was 2.0-fold higher (95% CI: 1.1-3.6; P = 0.02) in ACS patients with CEPI-CT < 300 s as compared with CEPI-CT >or = 300 s. Inclusion of diabetes, clopidogrel and beta blockers in a multivariate Cox regression model enhanced the predictive value of CEPI-CT (HR: 2.7). Inclusion of von Willebrand factor levels did not alter the HR for recurrent ACS (HR: 2.1; 95% CI: 1.1-5.2; P = 0.03) for CEPI-CT < 300 s, but reduced the HR for CADP-CT (HR: 2.8, 95% CI: 0.8-9.8; P = 0.11). CONCLUSION: Shortened CT values reflect biologically relevant platelet hyperfunction in patients with ACS because they predict recurrent ACS.  相似文献   
993.
994.
995.
少尿和血清尿素水平的升高是机体对血容量减少、心功能衰竭或败血症所致的血流动力学改变的生理反应。此后数小时内的临床决策可以决定一个病人是迅速痊愈还是出现急性肾衰竭(acute renal failure,ARF)导致的一系列严重并发症。尽管临床治疗在近期有了很大进展,急性肾衰竭的死亡率仍高达50%。H0与Sheridan对袢利尿剂——这一目前广泛应用且价格低廉的药物在急性肾衰竭治疗中的循证医学证据进行了荟萃分析(见本期第341页),结果发现袢利尿剂对预防或者治疗急性肾衰竭作用很小。  相似文献   
996.
J N Munck 《Journal of clinical oncology》2003,21(8):1648; author reply 1648-1648; author reply 1649
  相似文献   
997.
Exposure to trauma and stress has been linked with poor health, while forgiveness appears to be positively associated with health outcomes. The current study investigates whether traits such as forgiveness and ruminative tendencies predict levels of trauma and stress experienced by New York City residents on the 1‐year anniversary of the September 11th terrorist attack. Seventy‐one students and staff members (57 females, 14 males) of a graduate school in New York City were administered the Impact of Events Scale, the Perceived Stress Scale, and questionnaires designed for the purpose of this study to measure ruminative tendencies and forgiveness on September 11, 2002. Rumination predicted levels of trauma (p < 0.05) and perceived stress (p < 0.01). Lower levels of forgiveness predicted perceived stress (p < 0.05), but not trauma. Rumination mediated the relationship between forgiveness and perceived stress. These findings suggest that individuals with higher levels of rumination have an elevated risk of experiencing trauma and stress‐related symptoms following a traumatic event. Forgiveness is associated with lower levels of stress, but not trauma, perhaps because trauma is an extreme form of stress. Forgiveness appears to serve as a buffer against stress more so in individuals with low levels of rumination than in individuals with high levels of rumination. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
998.
BACKGROUND: There is no consensus regarding the optimal rate of follow-up in the post-bariatric surgery patient population. METHODS: The records of all patients who underwent laparoscopic Roux-en-Y gastric bypass from 2001 to 2003 were reviewed. Using patient zip codes, travel distances were calculated between the patients' places of residence and our clinic. Patients were then assigned to 1 of 3 cohorts according to the following distances: (1) < 50 miles, (2) 50 to 100 miles, and (3) > 100 miles. Patient compliance with follow-up appointments at 3 weeks, 3 months, 6 months, 9 months, and 12 months was analyzed. Linear trends were identified using the Mantel-Haenszel test. Age and sex were analyzed as possible predictors of compliance using the chi(2) test. P values < .05 were considered statistically significant. RESULTS: The study group comprised 150 patients (127 females and 23 males). The 3 cohorts contained 115, 21, and 14 patients, respectively. All patients in each cohort were compliant with the 3-week follow-up appointment. Although there were differences in compliance between cohorts at each of the remaining appointments, only the 9-month (70.3% vs 61.9% vs 35.7%) visit showed statistical significance (P = .035). The 6-month visit trended toward significance (85.2% vs 76.2% vs 64.3%; P = .088). Males were more likely to be compliant with the 12-month follow-up (P = .040). When controlling for sex, travel distance was also a predictor of compliance at this follow-up visit (P = .024). Age was not predictive of compliance (P = .827). CONCLUSION: Based on our findings, we conclude that travel distance from the clinic does not significantly affect compliance at the initial follow-up, 3-month, and 12-month appointments. However, distance does tend to affect compliance at the 6-month appointment and significantly affects compliance at the 9-month appointment. Males are more likely to be compliant at the 12 month follow-up visit. We must continue to strive for 100% follow-up in our post-bariatric surgery patients.  相似文献   
999.
1000.
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