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   167050篇
  免费   32332篇
  国内免费   2433篇
耳鼻咽喉   5247篇
儿科学   5861篇
妇产科学   2863篇
基础医学   5560篇
口腔科学   1800篇
临床医学   28573篇
内科学   50333篇
皮肤病学   7712篇
神经病学   16434篇
特种医学   6886篇
外科学   42343篇
综合类   386篇
现状与发展   73篇
一般理论   28篇
预防医学   8933篇
眼科学   3594篇
药学   2260篇
中国医学   63篇
肿瘤学   12866篇
  2024年   703篇
  2023年   4977篇
  2022年   1534篇
  2021年   3701篇
  2020年   6421篇
  2019年   2836篇
  2018年   8020篇
  2017年   7823篇
  2016年   8879篇
  2015年   8927篇
  2014年   16178篇
  2013年   16506篇
  2012年   6954篇
  2011年   6877篇
  2010年   11037篇
  2009年   14878篇
  2008年   6854篇
  2007年   5097篇
  2006年   7368篇
  2005年   4720篇
  2004年   3852篇
  2003年   2702篇
  2002年   2749篇
  2001年   3887篇
  2000年   3046篇
  1999年   3282篇
  1998年   3746篇
  1997年   3566篇
  1996年   3414篇
  1995年   3266篇
  1994年   1995篇
  1993年   1611篇
  1992年   1406篇
  1991年   1429篇
  1990年   1086篇
  1989年   1194篇
  1988年   1040篇
  1987年   880篇
  1986年   912篇
  1985年   731篇
  1984年   558篇
  1983年   527篇
  1982年   538篇
  1981年   419篇
  1980年   369篇
  1979年   317篇
  1978年   337篇
  1977年   407篇
  1975年   285篇
  1972年   308篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Summary: This is the first report of the largest study of blood pressure measurement in pregnancy in a New Zealand population using standardized definitions and methodology. Over 3,800 women who delivered in an 8-month period in the Wellington region were included in the study. Blood pressure measurement and the presence of oedema and proteinuria were recorded from booking until delivery and in the puerperium. Only 2.7% of women were unable to be contacted after delivery for details on outcomes. The results established normal ranges for blood pressure throughout pregnancy. The data show that Mood pressure greater than 140/90 until 35 weeks' gestation is outside 2 standard deviations at all gestations and justifies using these measurements as the definition of hypertension in pregnancy. The fall in blood pressure in the 2nd trimester was less than 1 mm Ffg per week in both the systolic and diastolic pressures. This fall was smaller than previously recorded in other studies. Gestational hypertension was the commonest blood pressure abnormality occurring in 15.2% of the population. This represented 69% of the pregnant women with a hypertensive disorder. The overall incidence of both gestational hypertension and preeclampsia was 18.5% which is higher than reported in other parts of the world. In this study obesity was significantly associated with hypertensive disorders in pregnancy. An arm circumference of >33 cm, one of the measurements of obesity, was found in 6.8% of the study population. Even after the effect of arm circumference was taken into account, hypertensive disorders were also more common in Pacific Island women. Ankle oedema was significantly associated with the development of both gestational hypertension and preeclampsia but the incidence of oedema was noted in only 11.9% of the subjects.  相似文献   
52.
The efficacy and safety of ketoprofen and paracetamol were compared for the treatment of acute migraine in a randomized, double-blind study of 64 patients. Thirty-four patients received ketoprofen 100 mg intramuscularly, and 30 patients received paracetamol 500 mg intramuscularly. Partial or complete relief of pain and other symptoms was achieved 15 to 20 minutes after administration in the ketoprofen group and within 35 minutes in the paracetamol group. Complete relief of pain was achieved within 30 to 40 minutes after ketoprofen in 28 patients (82.5%) compared to 5 patients (17.5%) in the paracetamol group. Six of the patients treated with ketoprofen needed a second dose for complete relief of pain during the 4-hour follow-up period. Side effects were rare and minimal. Our findings suggest that ketoprofen produced statistically significant benefit in the treatment of acute migraine.  相似文献   
53.
54.
55.
56.
57.
58.
59.
60.
BACKGROUND: Endothelin, a peptide with strong vasoconstrictive and mitogenic properties, has been found to increase after cardiac transplantation. We therefore assessed the association between its precursor peptide, big endothelin-1, and intimal hyperplasia and coronary flow reserve after heart transplantation. METHODS: Thirty-five patients without hemodynamically significant coronary artery disease after heart transplantation were investigated: Average peak flow velocity in the left anterior descending artery (LAD) was assessed by intracoronary Doppler at baseline as well as after injection of adenosine; coronary flow reserve was calculated as a ratio of both and was corrected for patient age and baseline average peak flow velocity. Lumen, intima + media and total vessel area were measured by intracoronary ultrasound. The plasma concentration of big endothelin-1 in venous blood was determined by radioimmunoassay. RESULTS: Patients with elevated big endothelin-1 levels (>2 fmol/ml) tended to have a decreased corrected coronary flow reserve (2.60 +/- 0.9 vs 3.21 +/- 1.0, p = 0.078). They also had a significantly larger intima + media area (5.82 +/- 2.9 vs 2.37 +/- 2.9 mm(2), p = 0.004) and total vessel area (18.36 +/- 5.8 vs 12.81 +/- 4.8 mm(2), p = 0.012) than those with normal plasma concentrations. CONCLUSIONS: Our study suggests an association between elevated big endothelin-1 plasma levels and the development of intimal hyperplasia and reduction of coronary flow reserve after cardiac transplantation.  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