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   58383篇
  免费   3134篇
  国内免费   554篇
耳鼻咽喉   811篇
儿科学   1913篇
妇产科学   998篇
基础医学   7350篇
口腔科学   1714篇
临床医学   4337篇
内科学   13814篇
皮肤病学   1690篇
神经病学   4630篇
特种医学   1502篇
外国民族医学   2篇
外科学   7970篇
综合类   1349篇
一般理论   21篇
预防医学   4774篇
眼科学   1568篇
药学   3781篇
  6篇
中国医学   546篇
肿瘤学   3295篇
  2024年   70篇
  2023年   475篇
  2022年   740篇
  2021年   1809篇
  2020年   983篇
  2019年   1732篇
  2018年   2427篇
  2017年   1530篇
  2016年   1374篇
  2015年   1431篇
  2014年   1861篇
  2013年   2669篇
  2012年   4438篇
  2011年   4805篇
  2010年   2482篇
  2009年   1743篇
  2008年   3715篇
  2007年   3742篇
  2006年   3384篇
  2005年   3444篇
  2004年   3100篇
  2003年   2925篇
  2002年   2666篇
  2001年   1680篇
  2000年   2034篇
  1999年   1234篇
  1998年   435篇
  1997年   292篇
  1996年   283篇
  1995年   257篇
  1994年   178篇
  1993年   178篇
  1992年   232篇
  1991年   192篇
  1990年   160篇
  1989年   161篇
  1988年   146篇
  1987年   129篇
  1986年   120篇
  1985年   109篇
  1984年   96篇
  1983年   67篇
  1982年   53篇
  1981年   49篇
  1980年   55篇
  1979年   38篇
  1978年   34篇
  1977年   37篇
  1976年   26篇
  1975年   33篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
The purpose of this study was to evaluate the ability of helical computed tomographic angiography (HCTA) to detect vascular injury in penetrating neck trauma. Thirty-five patients (30 gunshot wounds and 5 stab wounds) were studied prospectively with HCTA. Scans were performed with a 5-mm slice thickness at a 1:1 pitch after injection of 90 ml of nonionic contrast medium (30-second delay) at 3 ml/sec. Results were compared with those for angiography (29), surgery (3), ultrasound (2), and local inspection (1). HCTA correctly revealed 19 normal and 10 abnormal studies. In 8 cases, HCTA revealed irregular vessel margins (3), contrast extravasation (2), lack of vascular enhancement (1), and caliber changes (2). In 2 patients, HCTA revealed indirect signs of injury only. In 6 cases, HCTA findings did not correlate with angiography. HCTA detects both direct and indirect signs of vascular injury. Although indirect findings are more sensitive, the direct evaluation of vessels increases the specificity and has a high negative predictive value.  相似文献   
52.
Preparative temperature rising elution fractionation (TREF) on commercial linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) samples has been performed. The resulting fractions exhibited a bimodal and a unimodal distribution, respectively. Two LLDPE fractions of low (5 CH3/1000 C) and high (21 CH3/1000 C) short-chain branching content were solution-mixed with the LDPE central fraction (16 CH3/1000 C). Indirect evidence based on differential scanning calorimetry results suggest that the fractions with similar branch contents are more miscible than those with dissimilar ones.  相似文献   
53.
Studied children with mild to moderate juvenile rheumatoid arthritiswho were massaged by their parents 15 minutes a day for 30 days(and a control group engaged in relaxation therapy). The children'sanxiety and stress hormone (cortisol) levels were immediatelydecreased by the massage, and over the 30-day period their paindecreased on self-reports, parent reports, and their physician'sassessment of pain (both the incidence and severity) and pain-limitingactivities  相似文献   
54.
Adenosine monophosphate, inosine monophosphate, inosine, adenosine, guanosine, adenine, guanine, hypoxanthine, xanthine and uric acid were determined in cerebrospinal fluid (CSF) of 15 children after complex febrile seizures (CFS) and in 27 after simple febrile seizures (SFS), and compared with those in a control group of 63 children. There was no statistically significant difference between the groups for any of these metabolites, suggesting that CFS and SFS neither significantly disturb the metabolism of nucleotides, nucleosides or bases nor significantly deplete neuron adenosine triphosphate levels.  相似文献   
55.
PURPOSE: To compare two protocols of epidural administration of racemic methadone for postoperative analgesia (continuous infusion and intermittent bolus), focussing on plasma concentration, analgesic efficacy and side effects. METHODS: Ninety patients undergoing abdominal or lower-limb surgery were randomly assigned to two groups in a prospective double-blind design. The continuous infusion patients (n=60) received initial doses of 3 to 6 mg followed by 6 to 12 mg by continuous infusion over 24 hr. The bolus administration patients (n=30) received repeated boluses of 3 to 6 mg of racemic methadone every eight hours. Pain intensity was assessed on a visual analog scale. Amount of supplementary analgesia was recorded, as was the incidence of side effects. Plasma methadone concentrations were determined by high performance liquid chromatography. Treatment was continued for 72 hr. RESULTS: Pain relief was good and comparable in both groups throughout the three days of treatment. No accumulation of plasma racemic methadone was observed in either group, although the concentrations were significantly higher in the bolus group. Miosis was significantly more frequent in the bolus group. CONCLUSION: Plasma methadone concentrations were significantly lower with continuous infusion. Plasma methadone accumulation, which is considered the main disadvantage for its purported influence on the incidence of side effects, did not occur at the doses used over the three days of treatment that we report.  相似文献   
56.
57.
58.
59.
60.
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