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   1188946篇
  免费   85400篇
  国内免费   3819篇
耳鼻咽喉   16931篇
儿科学   30821篇
妇产科学   30664篇
基础医学   170641篇
口腔科学   36286篇
临床医学   102585篇
内科学   234081篇
皮肤病学   25346篇
神经病学   91419篇
特种医学   45719篇
外国民族医学   160篇
外科学   190754篇
综合类   26349篇
现状与发展   2篇
一般理论   286篇
预防医学   74786篇
眼科学   28746篇
药学   93810篇
  4篇
中国医学   3905篇
肿瘤学   74870篇
  2018年   12488篇
  2017年   9711篇
  2016年   10536篇
  2015年   11950篇
  2014年   16438篇
  2013年   23375篇
  2012年   31991篇
  2011年   33157篇
  2010年   19647篇
  2009年   18805篇
  2008年   31729篇
  2007年   33703篇
  2006年   34085篇
  2005年   32383篇
  2004年   31126篇
  2003年   29840篇
  2002年   29121篇
  2001年   72207篇
  2000年   74036篇
  1999年   61446篇
  1998年   14467篇
  1997年   12482篇
  1996年   12160篇
  1995年   11375篇
  1994年   10406篇
  1993年   9598篇
  1992年   45396篇
  1991年   43018篇
  1990年   41343篇
  1989年   40450篇
  1988年   36700篇
  1987年   35730篇
  1986年   33279篇
  1985年   31571篇
  1984年   22293篇
  1983年   18762篇
  1982年   9687篇
  1981年   8337篇
  1979年   19480篇
  1978年   12977篇
  1977年   11171篇
  1976年   9538篇
  1975年   10514篇
  1974年   12705篇
  1973年   11954篇
  1972年   11399篇
  1971年   10887篇
  1970年   10253篇
  1969年   9702篇
  1968年   8848篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
902.
Background: In elderly patients, opioids may cause prominent postoperative sedation and respiratory depression. We evaluated the influence of age on the effects of opioids and plasma concentrations of fentanyl and oxycodone in cardiac surgery patients.
Methods: Thirty (≥75 years, gender M9/F21) and 20 (≤60 years, gender M20/F0) patients scheduled to undergo cardiac surgery. A standard anesthesia with fentanyl as an opioid was used. Fentanyl plasma concentrations were measured at the end of surgery and 2 h later. After tracheal extubation, when the pain intensity was at least moderate, blood samples for fentanyl and oxycodone plasma concentration measurements were taken. Thereafter, oxycodone hydrochloride 0.05 mg/kg i.v. was administered. After 15 and 45 min, pain intensity, sedation and oxycodone plasma concentration were determined. This test protocol was repeated twice.
Results: The elderly had a higher plasma concentration of fentanyl at the end of surgery than younger patients (5.7±2.2 vs. 3.8±1.2 ng/ml, P =0.001). The plasma concentrations of oxycodone were comparable between the groups. The interval between the second and the third oxycodone dose was longer in the elderly patients ( P =0.036). Pain intensity on the verbal rating scale was lower at the 45-min assessment point after all three oxycodone test doses ( P =0.008) and sedation scores were significantly higher after the third dose in the elderly patients ( P =0.035).
Conclusions: In elderly patients, the plasma concentration of fentanyl was higher but plasma levels of oxycodone were at a similar level compared with middle-aged patients. However, the elderly patients had less pain and were more sedated after doses of oxycodone.  相似文献   
903.
Background and objective  The purpose of this study is to assess whether Chinese children with high apnea–hypopnea index (AHI) are sleepier by a modified Epworth Sleepiness Scale (ESS). Materials and methods  Records were retrospectively reviewed. We included children who were between 3 and 12 years old, admitted for overnight polysomnogram because of suspected obstructive sleep apnea syndrome (OSAS). A modified ESS was used to assess excessive daytime sleepiness (EDS) of the children. Results  One hundred ninety-two Chinese children were included. Children with high AHI, defined as AHI > 5.0, were sleepier than children with AHI less than or equal to 5. After adjustment by age, gender, and obesity, children with high AHI remained significantly sleepier. Modified ESS was significantly correlated with AHI (rho = 0.124, 95% CI = 0.004–0.281). Modified ESS score of >8 was the best cutoff point with the sensitivity and specificity of 0.29 and 0.91, respectively. The odds ratio of children with modified ESS > 10 having high AHI was 4.231 (95%CI = 1.248 to 14.338) and children with modified ESS > 8 had the highest odds ratio, 4.295(95%CI = 1.66 to 11.1), of having high AHI. Conclusion   Chinese children with high AHI appear to be sleepier than children with low AHI. Children with suspected OSAS and high modified ESS, i.e., ESS > 8, had significantly higher odds ratio of having high AHI. Increased sleepiness is a specific but not a sensitive symptom in snoring children with high AHI. Screening for EDS in snoring children may help us identify those with high AHI and prioritize the management of those children. All authors worked and the study was carried out in Kwong Wah Hospital in Hong Kong. There was no conflict of interest and no specific source of funding for the study.  相似文献   
904.
905.
906.
907.
A case of untreated fusarial onychomycosis leading to serious consequences is reported. Fusarium solani is a widespread fungus and an occasional human pathogen. It usually invades rapidly in immunocompromised hosts, and often results in a poor outcome despite treatment. We report a woman with diabetes mellitus who had untreated fusarial infection of the nails, which developed into subcutaneous fusariosis, superinfected by bacteria, and then evolved into osteomyelitis that subsequently resulted in septic shock. Early management of mycotic nails in immunocompromised hosts is crucial to prevent life‐threatening disease.  相似文献   
908.
909.
Background  Hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) is a synthetic fragrance ingredient. Case reports of allergy to HICC appeared in the 1980s, and HICC has recently been included in the European baseline series. Human elicitation dose–response studies performed with different allergens have shown a significant relationship between the patch-test threshold and the repeated open application test (ROAT) threshold, which mimics some real-life exposure situations. Fragrance ingredients are special as significant amounts of allergen may evaporate from the skin.
Objectives  The study aimed to investigate the relationship between elicitation threshold doses at the patch test and the ROAT, using HICC as the allergen. The expected evaporation rate was calculated.
Materials and methods  Seventeen HICC-allergic persons were tested with a dilution series of HICC in a patch test and a ROAT (duration up to 21 days). Seventeen persons with no HICC allergy were included as control group for the ROAT.
Results  The response frequency to the ROAT (in μg HICC cm−2 per application) was significantly higher than the response frequency to the patch test at one of the tested doses. Furthermore the response rate to the accumulated ROAT dose was significantly lower at half of the doses compared with the patch test. The evaporation rate of HICC was calculated to be 72% over a 24-h period.
Conclusions  The ROAT threshold in dose per area per application is lower than the patch test threshold; furthermore the accumulated ROAT threshold is higher than the patch test threshold, which can probably be explained by the evaporation of HICC from the skin in the open test.  相似文献   
910.
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