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   1615篇
  免费   115篇
  国内免费   6篇
耳鼻咽喉   18篇
儿科学   52篇
妇产科学   8篇
基础医学   230篇
口腔科学   45篇
临床医学   142篇
内科学   369篇
皮肤病学   14篇
神经病学   137篇
特种医学   238篇
外国民族医学   1篇
外科学   120篇
综合类   20篇
预防医学   137篇
眼科学   33篇
药学   88篇
肿瘤学   84篇
  2020年   11篇
  2018年   15篇
  2017年   13篇
  2016年   16篇
  2015年   19篇
  2014年   36篇
  2013年   63篇
  2012年   41篇
  2011年   54篇
  2010年   48篇
  2009年   42篇
  2008年   38篇
  2007年   55篇
  2006年   41篇
  2005年   42篇
  2004年   45篇
  2003年   35篇
  2002年   39篇
  2001年   23篇
  2000年   30篇
  1999年   28篇
  1998年   55篇
  1997年   64篇
  1996年   57篇
  1995年   52篇
  1994年   50篇
  1993年   36篇
  1992年   34篇
  1991年   41篇
  1990年   43篇
  1989年   48篇
  1988年   51篇
  1987年   36篇
  1986年   56篇
  1985年   48篇
  1984年   33篇
  1983年   34篇
  1982年   28篇
  1981年   18篇
  1980年   17篇
  1979年   15篇
  1978年   20篇
  1977年   20篇
  1976年   22篇
  1975年   17篇
  1974年   11篇
  1973年   11篇
  1969年   10篇
  1968年   11篇
  1967年   11篇
排序方式: 共有1736条查询结果,搜索用时 15 毫秒
1.
2.
To assess the vascular involvement of renin-angiotensin system inhibition in human hypertension, acute effects of intravenous enalaprilat on brachial artery diameter, blood flow, and blood velocity were investigated in hypertensive patients by pulsed Doppler technique and compared with effects of saline vehicle. Compared with saline vehicle, enalaprilat reduced blood pressure (P less than 0.001) and increased brachial arterial diameter (P less than 0.01) and brachial blood flow (P less than 0.01). Enalaprilat effect on arterial pulse pressure was dependent on preinjection pulse pressure (r = -0.76; P less than 0.001), but its effect on mean blood pressure was not dependent on preinjection mean blood pressure. On the other hand, enalaprilat effect on arterial blood flow was negatively correlated with preinjection blood pressure (r = -0.64; P less than 0.02). The findings point to different responses of large and small arteries to intravenous enalaprilat.  相似文献   
3.
Ruggieri  PM; Laub  GA; Masaryk  TJ; Modic  MT 《Radiology》1989,171(3):785-791
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.  相似文献   
4.
5.
Interferon-α is the only approved and effective treatment for hepatitis C. Psychiatric side effects are common and have frequently required a decrease in dose or discontinuation of therapy. We here report a case of interferon-α-induced depression in a 40-yr-old man with hepatitis C successfully treated with the antidepressant fluoxetine, which allowed completion of interferon treatment.  相似文献   
6.
7.
8.
FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease.  相似文献   
9.
Objective . To describe the importance of migraine in Santiago, Chile, by analyzing its prevalence, clinical features and impact by age, gender and socioeconomic status. Methods . In 1993, a representative sample of 1,540 adults of the province of Santiago were interviewed using a standard questionnaire. A total of 1,385 (89.9%) subjects responded to the survey. Initially, a designated member of each household responded to the questionnaire. Subsequently, each household member with headaches was asked to respond to questions about severity, frequency, location, duration, associated symptoms and impact in work and social activities of their most frequent headaches. Migraine diagnoses were determined in accordance with the International Headache Society (IHS) criteria of 1988. Results. Recurrent headaches in the past year were found in 516 (36.82%) respondents, 145 (28.1%) males and 371 (71.9%) females. Total prevalence of migraine was found to be 7.3% (95%, CI 5.9–8.6); 11.9% (95% CI 9.6–14.2) in females and 2.0% (95% CI 0.9–3.0) in males. Overall, migraine constituted 19.6% (101/516) of all headaches reported in this sample. The prevalence did not vary significantly by age groups or socioeconomic status (SES). Migraine with aura had an overall prevalence of 3.5% (CI 0.8–7.1), and was significantly more frequent in females. In 60–70% of cases the attacks lasted 2–6 h and the frequency was 3.3 and 3.4 per month in females and males respectively. Both males and females reported significantly high percentages of attacks during work. Conclusions . Migraine prevalence in a sample of adults of Santiago is similar to that reported in previous studies using IHS criteria. Women of all socioeconomic levels are at an increased risk.  相似文献   
10.
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