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   149656篇
  免费   31179篇
  国内免费   2389篇
耳鼻咽喉   5163篇
儿科学   5342篇
妇产科学   2378篇
基础医学   2941篇
口腔科学   1464篇
临床医学   26653篇
内科学   46959篇
皮肤病学   7414篇
神经病学   14687篇
特种医学   6384篇
外科学   40772篇
综合类   231篇
现状与发展   72篇
一般理论   2篇
预防医学   6955篇
眼科学   3319篇
药学   872篇
中国医学   8篇
肿瘤学   11608篇
  2024年   684篇
  2023年   4778篇
  2022年   1169篇
  2021年   3045篇
  2020年   6001篇
  2019年   2120篇
  2018年   7338篇
  2017年   7306篇
  2016年   8372篇
  2015年   8364篇
  2014年   15426篇
  2013年   15549篇
  2012年   5349篇
  2011年   5347篇
  2010年   10295篇
  2009年   14182篇
  2008年   5714篇
  2007年   3925篇
  2006年   6394篇
  2005年   3678篇
  2004年   2948篇
  2003年   1945篇
  2002年   2036篇
  2001年   3785篇
  2000年   3011篇
  1999年   3208篇
  1998年   3641篇
  1997年   3462篇
  1996年   3356篇
  1995年   3212篇
  1994年   1943篇
  1993年   1563篇
  1992年   1384篇
  1991年   1406篇
  1990年   1050篇
  1989年   1174篇
  1988年   1011篇
  1987年   847篇
  1986年   881篇
  1985年   721篇
  1984年   549篇
  1983年   522篇
  1982年   516篇
  1981年   402篇
  1980年   363篇
  1979年   309篇
  1978年   335篇
  1977年   398篇
  1975年   280篇
  1972年   305篇
排序方式: 共有10000条查询结果,搜索用时 0 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