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   466篇
  免费   41篇
  国内免费   1篇
耳鼻咽喉   10篇
儿科学   21篇
妇产科学   5篇
基础医学   79篇
口腔科学   5篇
临床医学   85篇
内科学   54篇
皮肤病学   2篇
神经病学   79篇
特种医学   21篇
外科学   61篇
综合类   16篇
预防医学   22篇
眼科学   5篇
药学   22篇
中国医学   1篇
肿瘤学   20篇
  2021年   7篇
  2018年   5篇
  2017年   5篇
  2016年   6篇
  2015年   9篇
  2014年   4篇
  2013年   7篇
  2012年   11篇
  2011年   18篇
  2010年   13篇
  2009年   5篇
  2008年   11篇
  2007年   15篇
  2006年   19篇
  2005年   14篇
  2004年   21篇
  2003年   19篇
  2002年   12篇
  2001年   19篇
  2000年   18篇
  1999年   22篇
  1998年   20篇
  1997年   16篇
  1996年   17篇
  1995年   9篇
  1994年   4篇
  1993年   12篇
  1992年   15篇
  1991年   12篇
  1990年   12篇
  1989年   13篇
  1988年   8篇
  1987年   10篇
  1986年   8篇
  1985年   7篇
  1984年   4篇
  1983年   8篇
  1982年   7篇
  1981年   7篇
  1978年   5篇
  1977年   4篇
  1976年   6篇
  1975年   4篇
  1974年   9篇
  1973年   2篇
  1972年   2篇
  1969年   2篇
  1966年   2篇
  1875年   6篇
  1871年   3篇
排序方式: 共有508条查询结果,搜索用时 31 毫秒
121.
Acute graft-versus-host disease (GVHD) that is resistant to therapy is a highly lethal complication of marrow transplantation. Inflammatory cytokines such as interleukin-1 (IL-1) may be critical mediators of this process. If so, specific inhibition of IL-1 activity with recombinant human IL-1 receptor antagonist (IL-1Ra), a naturally occurring competitive inhibitor of IL-1, may ameliorate acute GVHD. We performed an open-label, phase I/II trial to evaluate the safety and efficacy of IL-1Ra in 17 patients with steroid-resistant GVHD. The IL- 1Ra was administered as a 24-hour continuous infusion over 7 days. The dose was escalated in cohorts of patients from 400 to 3,200 mg/d. Acute GVHD was evaluated in each affected organ and as an overall grade. Stage-specific improvement of acute GVHD occurred in the skin (8 of 14, 57%), gut (9 of 11, 82%), and liver (2 of 11, 18%). Overall, acute GVHD improved by at least one grade in 10 of 16 (63%) patients. Response to therapy was associated with a reduction of tumor necrosis factor-alpha (TNF-alpha) mRNA levels in blood mononuclear cells (P = .001). The only toxicity attributable to IL-1Ra was reversible transaminase elevation in two patients. Inhibition of IL-1 activity with IL-1Ra is safe and has demonstrable efficacy in acute GVHD that failed to respond to conventional treatment. These data provide further evidence that IL-1 is a mediator of GVHD.  相似文献   
122.
In a randomized, controlled trial of recombinant interferon alfa-2b with or without prednisone priming in Chinese adults with chronic hepatitis B virus infection, stratified randomization for pretreatment serum alanine aminotransferase levels was done. Partial or complete antiviral responses were achieved in 17 (21.5%) of 79 treated patients and 3 (8.3%) of 36 controls (P = 0.14). The response to interferon treatment was significantly better in those who had elevated pretreatment transaminase levels and comparable to that reported in white patients [15 (38.5%) of 39 patients compared with 2 (5%) of 40 who had normal pretreatment transaminase levels (P = 0.0005)]. The spontaneous seroconversion rate was also higher among the controls with elevated transaminase levels [3 (18.8%) of 16 compared with 0 of 20 with normal transaminase levels], but this difference was not statistically significant (P = 0.16). Among the interferon-treated patients, prednisone priming appeared to have a marginal benefit over treatment with interferon alone in patients with elevated transaminase levels (43% vs. 33%), but not in those with normal transaminase levels (0% vs. 9.5%). It was confirmed that Chinese patients with normal transaminase levels respond very poorly to interferon alfa therapy. However, the response was significantly better in patients with elevated transaminase levels.  相似文献   
123.
Short sequences in hypervariable regions of the hepatitis B virus (HBV) genome can be used to identify different strains, providing a novel approach to the study of HBV transmission. The nucleotide sequence in positions 2551-2650 (1:EcoRI site) was determined for serum HBV DNA from 96 Chinese children living in Hong Kong and from 38 of their parents. HBV DNA was extracted and sequenced after amplification with the polymerase chain reaction, using as primers oligonucleotides corresponding to two conserved sequences. Among 82 unrelated children, 32 HBV DNA variants were present. One sequence was present in 33 children and 31 variants were found among the other 49. Siblings within each of nine families had the same variant; in three families siblings had different variants. Six of the eight fathers and 28 of the 30 mothers had HBV DNA sequences identical to those of their offspring. A total of 34 variants were found among the 134 individuals. The hypothesis of random assortment of sequences in parents and children was rejected (P less than .00005). Thus, this new approach proves the occurrence of intrafamilial transmission of HBV among Chinese.  相似文献   
124.
125.
126.
127.
A 12-month prospective study was carried out in 120 Chinese patients with gestational diabetes who were found to have persistent carbohydrate intolerance at 6 weeks postpartum. The 75 g OGTT and WHO diagnostic criteria were employed for both antepartum and postpartum assessment. By 12 months, persistent carbohydrate intolerance was found in 13.3% of the patients only, 6 patients were diabetic while 10 had impaired glucose tolerance. Of those whose carbohydrate tolerance reverted to normal, 85% did so within the first 6 months. The clinical variables were analysed by multiple discriminant analysis using the logistic model. Five prognostic variables which were predictive of persistent carbohydrate intolerance at 12 months were identified. In order of decreasing predictive value, these included a high fasting glucose during pregnancy and at the first postnatal visit, a high antepartum 2 h blood glucose, the requirement of insulin during pregnancy, and a high postpartum 2 h blood glucose. Macrosomia, gestational age at diagnosis and a family history of diabetes were not predictive of persistent carbohydrate intolerance. Multiparity, maternal age and body mass index were of marginal significance only. The fitted logistic model provides a mechanism to estimate the probability of persistent carbohydrate intolerance. Such information will be helpful in patient counselling and in the efficient planning of postpartum medical follow-up.  相似文献   
128.
BACKGROUND: Imbalanced amino acid diets in animals rapidly produce anorexia and weight loss. Blockade of type 3 serotonergic receptors (5HT(3)) can ameliorate anorexia in this animal model. Imbalanced plasma amino acid levels also have been documented in both animal models and human patients with cancer cachexia. Therefore a trial of the 5HT(3) receptor antagonist, ondansetron, was undertaken in the treatment of patients with cancer cachexia. METHODS: Patients with metastatic cancer who were not undergoing chemotherapy or radiotherapy and who had lost >5% of their body weight were eligible. Baseline physical examination; weight; anthropometric studies; levels of retinol binding protein, albumin, and prealbumin; and skin testing for anergy were obtained. The ability to enjoy food was assessed utilizing a seven-point hedonic category scale for specific foods. Therapy was comprised of oral ondansetron, 8 mg twice a day. RESULTS: Twenty-seven patients were enrolled; all were evaluable for toxicity and 20 patients were evaluable for response. Toxicity of ondansetron was minimal. Patients demonstrated significant weight loss prior to disease entry (mean baseline weight of 76.9 kg vs. 72. 1 kg; P < 0.000002). Patients continued to lose weight on study (Week 0: 72.5 kg vs. Week 4: 71.4 kg; P = 0.027); in addition, there was significant deterioration of midarm circumference and hand grip strength, all of which indicated worsening nutritional status. However, a significant improvement in food enjoyment was noted (P = 0.04). CONCLUSIONS: Although it apparently improved the ability of patients to enjoy food, the blockade of 5HT(3) receptors failed to prevent weight loss in patients with cancer cachexia or alter laboratory parameters of protein nutrition.  相似文献   
129.
Sickle cell disease (SCD) is associated with early mortality. We sought to determine the incidence, cause, and risk factors for death in an adult population of patients with SCD. All patients aged ≥18 years seen at the Adult Sickle Cell Center at Duke University Medical Center between January 2000 and April 2005 were enrolled. Forty‐three patients (21 males and 22 females) died during the study period. The median age of survival was 39 years for females (95% CI: 34–56), 40 years for males (95% CI: 34–48), and 40 years overall (95% CI: 35–48). Cardiac causes of death accounted for 25.6% (11/43 patients); pulmonary, 14.0% (six patients); other SCD related, 32.6% (14 patients); unknown, 14.0% (six patients); and others, 14.0% (six patients). Pulseless electrical activity arrest, pulmonary emboli, multiorgan failure, and stroke were the most frequent causes of death. Among the deceased patients, the most common premorbid conditions were cardiopulmonary: acute chest syndrome/pneumonia (58.1%), Pulmonary hypertension (pHTN; 41.9%), systemic HTN (25.6%), congestive heart failure (25.6%), myocardial infarction (20.9%), and arrhythmias (14.0%). Tricuspid regurgitant jet velocity was significantly higher (3.1 m/sec vs. 2.6 m/sec, P < 0.001) and hemoglobin significantly lower (8.3 g/dL vs. 9.2 g/dL, P < 0.05) in deceased patients when compared with patients who lived, respectively. With improved preventive and therapeutic advances, including hydroxyurea therapy, acute complications such as infection are no longer the leading cause of death; instead, causes of death and premorbid conditions are shifting to chronic cardiopulmonary complications. Further, arrhythmia leading to premature death is under‐recognized in SCD and warrants further investigation. Am. J. Hematol., 2010. © 2009 Wiley‐Liss, Inc.  相似文献   
130.
Acknowledgements     
A surveyor's flexicurve has been used to measure kyphosis and lordosis in a cross-sectional study of men and women aged 20–90 years. No age effect was found in men aged 20–59 years or in women aged 20–49 years. Linear regressions showed an increase in kyphosis with age in older men and women. Various indices were examined to test their suitability as estimates of kyphosis. Lordosis was absent in an increasingly large proportion of men and women as age rose above 60 years.  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