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   731227篇
  免费   51596篇
  国内免费   1363篇
耳鼻咽喉   9399篇
儿科学   23856篇
妇产科学   18075篇
基础医学   114154篇
口腔科学   20569篇
临床医学   66217篇
内科学   139323篇
皮肤病学   16619篇
神经病学   52355篇
特种医学   26831篇
外国民族医学   131篇
外科学   108143篇
综合类   15151篇
现状与发展   2篇
一般理论   169篇
预防医学   53470篇
眼科学   17081篇
药学   55770篇
  3篇
中国医学   2389篇
肿瘤学   44479篇
  2021年   5793篇
  2019年   5793篇
  2018年   8267篇
  2017年   6447篇
  2016年   7192篇
  2015年   8058篇
  2014年   10933篇
  2013年   16386篇
  2012年   21980篇
  2011年   23041篇
  2010年   13573篇
  2009年   12729篇
  2008年   21460篇
  2007年   23103篇
  2006年   23396篇
  2005年   21956篇
  2004年   21458篇
  2003年   20322篇
  2002年   19780篇
  2001年   36702篇
  2000年   37209篇
  1999年   30707篇
  1998年   8168篇
  1997年   6951篇
  1996年   7215篇
  1995年   6861篇
  1994年   6296篇
  1992年   23180篇
  1991年   23121篇
  1990年   22475篇
  1989年   22259篇
  1988年   20214篇
  1987年   19600篇
  1986年   18627篇
  1985年   17474篇
  1984年   12914篇
  1983年   10926篇
  1982年   6144篇
  1979年   11675篇
  1978年   8271篇
  1977年   6935篇
  1976年   6732篇
  1975年   7384篇
  1974年   8644篇
  1973年   8247篇
  1972年   7752篇
  1971年   7216篇
  1970年   6939篇
  1969年   6367篇
  1968年   5840篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
991.
992.
993.
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   
994.
J N Munck 《Journal of clinical oncology》2003,21(8):1648; author reply 1648-1648; author reply 1649
  相似文献   
995.
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   
996.
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   
997.
998.
999.
The component of a composite prosthesis, which makes contact with the visceral peritoneum, can be reabsorbable or non-reabsorbable, and laminar or reticular. This study was designed to determine whether the composition of this second, barrier component could improve its behavior at this interface. Abdominal wall defects in rabbits were repaired using a polypropylene prosthesis (PP), or the composites Sepramesh (PP+h) or Vicryl (PP+v). Fourteen days after surgery, the implants were evaluated by light and scanning electron microscopy, and immunohistochemistry. Prosthetic areas occupied by adhesions (PP: 71.08±5.09, PP+h: 18.55±4.96, P+v: 69.69±16.81%), neoperitoneal thickness (PP: 256.17±21.68, PP+h: 83.11±19.63, PP+v:213.72±35.90 μm) and macrophage counts (PP: 8.73±1.16, PP+h: 27.33±4.13, PP+v: 31.24±3.08%) showed significant differences (P<0.05). The tested biomaterials induced an optimal recipient tissue infiltration. Least adhesion formation was observed on the PP+h implants. This suggests that the second component, although reabsorbable, should be smooth in structure.  相似文献   
1000.
This study attempted to evaluate the efficacy of chronic extra-aortic counterpulsation with a latissimus dorsi neuro vascular flap. Five dogs had a preliminary procedure consisting of the creation of a latissimus dorsi flap and a thoracotomy in which the flap was wrapped around the descending aorta just distal to the left subclavian artery. An epicardial lead was placed on the left ventricle and a nerve stimulating lead placed around the thoraco-dorsal nerve. Three weeks later, both leads were connected to a cardiomyostimulator programmed to function in a counterpulsation mode with a 1:2 assist frequency. Hemodynamic measurements were made at 6 and 8 and 10 and 12 weeks and the dogs were sacrificed. Three dogs had all sets of hemodynamic measurements made. Two of the three dogs demonstrated diastolic augmentation at 6 and 8 and 10 and 12 weeks average 20 to 25 mmHg. The third dog failed to demonstrate any change. All dogs were sacrificed at 12 weeks and specimens were submitted for histologic evaluation. The muscle flap was preserved in all animals. The aorta subjacent to the flap showed, (1) normal intima with no evidence of disruption or thrombus in all animals, (2) in the animals in whom counterpulsation was observed, there appeared to be thinning of the media in the aorta subjacent to the muscle flap, and (3) no evidence of distal emboli. This study demonstrated that chronic counterpulsation can be obtained with a latissimus dorsi flap. The actual hemodynamic benefits are not determined from this study. The medial thinning in the aortic wall may limit the long-term benefit of this procedure.  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