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   1230篇
  免费   180篇
  国内免费   17篇
耳鼻咽喉   12篇
儿科学   50篇
妇产科学   11篇
基础医学   65篇
口腔科学   14篇
临床医学   204篇
内科学   314篇
皮肤病学   29篇
神经病学   61篇
特种医学   87篇
外科学   296篇
综合类   58篇
现状与发展   20篇
预防医学   85篇
眼科学   28篇
药学   28篇
中国医学   2篇
肿瘤学   63篇
  2024年   6篇
  2023年   44篇
  2021年   22篇
  2020年   25篇
  2019年   13篇
  2018年   56篇
  2017年   52篇
  2016年   37篇
  2015年   45篇
  2014年   52篇
  2013年   72篇
  2012年   33篇
  2011年   44篇
  2010年   57篇
  2009年   77篇
  2008年   55篇
  2007年   47篇
  2006年   49篇
  2005年   30篇
  2004年   25篇
  2003年   29篇
  2002年   29篇
  2001年   25篇
  2000年   32篇
  1999年   35篇
  1998年   33篇
  1997年   32篇
  1996年   45篇
  1995年   33篇
  1994年   19篇
  1993年   23篇
  1992年   15篇
  1991年   9篇
  1990年   12篇
  1989年   17篇
  1988年   18篇
  1987年   23篇
  1986年   12篇
  1985年   14篇
  1984年   6篇
  1983年   7篇
  1982年   8篇
  1980年   7篇
  1978年   16篇
  1977年   10篇
  1976年   9篇
  1975年   6篇
  1971年   5篇
  1967年   6篇
  1964年   6篇
排序方式: 共有1427条查询结果,搜索用时 15 毫秒
1.
2.
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   
3.
4.
A randomized controlled trial of sedation in the critically ill   总被引:2,自引:0,他引:2  
A randomized controlled trial comparing: a) a combination of oral chloral hydrate and promethazine to b) a continuous intravenous midazolam infusion, for maintenance sedation in critically ill children, was carried out. The level of sedation was assessed four hourly using a specifically devized sedation scale. Forty-four children entered the study of whom two were subsequently excluded. The number of satisfactory assessments (desired and actual levels of sedation equal) was significantly greater in the chloral hydrate and promethazine group (Chi-squared P <0.01; confidence intervals of the difference 0.06 to 0.20). The number of assessments at level 5 on the sedation scale (patient restless/distressed) was significantly greater in the midazolam group (Chi-squared P <0.05). The total number of satisfactory assessments in the two groups were only 61 and 48% respectively, suggesting that sedation can be considerably improved. Chloral hydrate and promethazine are more effective than midazolam as maintenance sedation in critically ill children. It is possible to prospectively study the efficacy of sedative drugs in critically ill children.  相似文献   
5.
6.
7.
Summary After treatment of a symptomatic herniated disc with chymopapain, 14 patients were re-examined by magnetic resonance imaging (MRI) at a mean follow-up of 72 months. Well-defined MRI findings before chemonucleolysis were compared with those after the procedure by an independent observer. Five MRI parameters were assessed. No significant change was noted in the signal intensity of the affected disc, the extent of osteochondrosis and endplate reaction of the affected segment. The height of the affected disc as well as the size of the disc herniation were reduced significantly. The loss of the height is seen as a direct result of chymopapain activity, whereas the alteration of the size of the herniation seems to depend on the natural history of a disc herniation and is probably not a simple result of the treatment.  相似文献   
8.
BACKGROUND: The objective of this study was to evaluate the relationship between food allergy and asthma morbidity in adults. METHODS: We interviewed a cohort of persistent asthmatics from an inner-city clinic. Allergies to food were assessed by patient report of convincing symptoms of acute allergic reactions. Outcome variables included health resource utilization and medication use. RESULTS: The prevalence of allergy to fish, peanut, tree-nut, shellfish, and seed allergies were 3%, 3%, 3%, 13%, and 1%. Patients with allergies to > 1 food had increased asthma hospitalizations, ED visits, and use of oral steroids (p < 0.05 for all comparisons). Specifically, allergy to fish was associated with a greater risk of health resource utilization and increased frequency of oral steroid use (p < or = 0.03 for all comparisons). CONCLUSIONS: Self-reported allergy to foods was associated with worse outcomes, suggesting that food allergy may be a risk factor for increased asthma morbidity in adults.  相似文献   
9.
Adult umbilical hernia is a common surgical condition mainly encountered in the fifth and sixth decade of life. Despite the high frequency of the umbilical hernia repair procedure, disappointingly high recurrence rates, up to 54% for simple suture repair, are reported. Since both mesh and suture techniques are used in our clinic we set out to investigate the respective recurrence rates and associated complications, retrospectively. Patients who were treated between January 1998 and December 2002 were identified from our hospital database and invited to attend the outpatient department for an extra follow-up, history taking and physical examination. The use of prosthetic material, occurrence of surgical site infection, body mass and height as well as recurrence were recorded at the time of this survey. In total, 131 consecutive patients underwent operative repair of an umbilical hernia. Twenty-eight percent of the patients were female (n=37). In 12 patients (11%) umbilical hernia repair was achieved with mesh implantation. Fourteen umbilical hernia recurrences were noted (13%); none had been repaired using mesh. No relationship was found between wound infection or obesity and umbilical hernia recurrence. In the light of these results it is necessary to re-evaluate our clinical “guidelines” on mesh placement in umbilical hernia repair: apparently not every umbilical fascial defect needs mesh repair. Research should focus on establishing risk factors for hernia recurrence.  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