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   1036篇
  免费   57篇
  国内免费   2篇
儿科学   31篇
妇产科学   6篇
基础医学   63篇
口腔科学   15篇
临床医学   80篇
内科学   252篇
皮肤病学   15篇
神经病学   14篇
特种医学   133篇
外科学   67篇
综合类   25篇
预防医学   45篇
眼科学   8篇
药学   52篇
中国医学   2篇
肿瘤学   287篇
  2023年   3篇
  2022年   10篇
  2021年   20篇
  2020年   7篇
  2019年   12篇
  2018年   27篇
  2017年   7篇
  2016年   14篇
  2015年   27篇
  2014年   26篇
  2013年   38篇
  2012年   37篇
  2011年   32篇
  2010年   38篇
  2009年   47篇
  2008年   38篇
  2007年   36篇
  2006年   50篇
  2005年   58篇
  2004年   40篇
  2003年   31篇
  2002年   34篇
  2001年   26篇
  2000年   22篇
  1999年   27篇
  1998年   31篇
  1997年   31篇
  1996年   34篇
  1995年   25篇
  1994年   28篇
  1993年   24篇
  1992年   10篇
  1991年   15篇
  1990年   11篇
  1989年   26篇
  1988年   20篇
  1987年   18篇
  1986年   20篇
  1985年   13篇
  1984年   8篇
  1983年   7篇
  1982年   9篇
  1981年   9篇
  1980年   3篇
  1979年   6篇
  1978年   7篇
  1977年   13篇
  1976年   8篇
  1975年   10篇
  1968年   2篇
排序方式: 共有1095条查询结果,搜索用时 15 毫秒
1.
2.
Background Significant tumor downstaging has been achieved in patients with localized gastric or gastroesophageal adenocarcinoma by induction chemotherapy and preoperative chemoradiotherapy (CTX–CTXRT). However, the influence of CTX–CTXRT on operative morbidity and mortality has not yet been clarified. The aim of the present study was to document the frequency and nature of morbidity and mortality after surgery combined with CTX–CTXRT, and identify factors predictive of postoperative complications in patients with localized gastric or gastroesophageal adenocarcinoma. Methods A prospectively collected database on 71 consecutive patients who underwent CTX–CTXRT at M.D. Anderson Cancer Center between January 1997 and August 2004 was reviewed. Postoperative morbidity and mortality were investigated, and risk factors for overall complications were identified by multivariate logistic regression analysis. Results Overall morbidity and mortality rates were 38.0% (27 patients) and 2.8% (2 patients), respectively. Age greater than 60 years [relative risk 11.3 (95% confidence interval 2.50–50.6)] and body mass index (BMI) of 26 kg/m2 or above [relative risk 4.08 (95% confidence interval 1.08–15.4)] were significant risk factors for overall complications. Conclusions CTX–CTXRT can be performed safely with an acceptable operative morbidity and a low operative mortality rate in patients with gastric or gastroesophageal cancer, with careful consideration of added risk associated with age and obesity.  相似文献   
3.
Intracerebral vascular reactivity induced by the nitric oxide (NO) donor isosorbide dinitrate (IDN, 5 mg sublingually) is more major and longer-lasting in migraine patients who develop delayed headache in response to the drug. The headache is purportedly due to neuronally-mediated vascular mechanisms. Indomethacin inhibits prostaglandin synthesis, which is involved in NO generation. Indomethacin also decreases cerebral blood flow by constricting precapillary resistance vessels. In the present study, the hemodynamic effects of indomethacin were evaluated in migraine patients and healthy controls by means of transcranial Doppler monitoring. Indomethacin caused a significant decrease in mean flow velocity in the middle cerebral artery. This was an additional effect to the mean velocity decrease induced by IDN. The interactions between the two drugs suggest that their effects on cerebral hemodynamics (and pain) may be of relevance both in understanding the role of NO in migraine pathogenesis and in evaluating symptomatic treatments for migraine attacks.  相似文献   
4.
5.
OBJECTIVE: To examine glucose tolerance in sputum-positive non-treated pulmonary tuberculosis (TB) patients as part of a general metabolic profile. Subjects. Sixty-three sputum-positive non-treated patients (male and female) attending the pulmonary clinic at Mthatha General Hospital in the Eastern Cape and 89 apparently healthy sex and age-matched volunteers. METHODS: Sixty-three untreated TB patients who came to the Mthatha General Hospital's pulmonary clinic with classic symptoms of TB, confirmed by sputum analysis, were recruited for the study. Eighty-nine apparently healthy sex and age-matched volunteers served as the control group. Anthropometric measurements were taken using an electronic scale. Standard oral glucose tolerance tests (OGTTs) were performed in both groups in the morning after an overnight fast. Anticoagulant-treated blood was analysed for glucose and insulin using Peridochrome Glucose (Boehringer Mannheim, Mannheim, Germany) and radioimmunoassay (RIA) (Diagnostic Products Corporation, Los Angeles, USA) respectively. RESULTS: There was sluggish response to glucose and insulin in the TB patient group compared with the control group. Glucose and insulin levels were significantly higher in patients at 0, 30, 60, 120, and 180 minutes. Analysis of variance gave the following p-values, viz. p = 0.0000, 0.0004, 0.0000, 0.0000 and 0.0000 for glucose, and p = 0.0317, 0.0071, 0.0000, 0.0005 and 0.0000 for insulin respectively. CONCLUSIONS: The results of this study suggest an altered glucose/insulin metabolism in TB patients. This might play an important role in the clinical course of the disease.  相似文献   
6.
The effect of a continuous i.v. infusion of alpha-difluoromethylornithine (DFMO) on the polyamine metabolism of tumor and normal host tissue was determined. Non-tumor-bearing Fischer 344 rats or rats bearing a transplantable fibrosarcoma received continuous infusions of DFMO through a central venous catheter at three dose levels. Treatment with DFMO resulted in a time- and dose-dependent, cytostatic effect on the growth of the tumor. In fibrosarcoma-bearing rats the tumor putrescine levels were reduced after 6 and 12 days of DFMO treatment. Tumor spermidine levels were consistently reduced after 6 and 12 days of treatment with the reduction being dose dependent. The decrease in tumor ornithine decarboxylase activity was dose dependent. Erythrocyte putrescine levels were decreased in tumor- and non-tumor-bearing rats, suggesting that DFMO reduces the tumor contribution to the erythrocyte pool. Erythrocyte spermidine levels of fibrosarcoma- and non-tumor-bearing rats were elevated at the lower DFMO doses administered for 12 days but returned to normal as the dose was increased. Erythrocyte spermine levels were elevated in both groups of rats at all DFMO doses. Although normal host tissue weights were not affected by treatment with DFMO, the putrescine and spermidine levels of liver, spleen, and kidney and ornithine decarboxylase activity of the liver and kidney were decreased. These data demonstrate that i.v. DFMO has a cytostatic effect toward a rapidly growing fibrosarcoma associated with the depletion of both tumor putrescine and spermidine levels.  相似文献   
7.
Objective: Right upper lobe collapse is a common radiographic finding in intubated children. We hypothesized that deep suctioning and uncontrolled negative pressures during endotracheal tube suctioning were significant contributory factors. Methods : The incidence of right upper lobe (RUL) collapse in intubated, ventilated children on a paediatric cardiac intensive care unit was determined over a 3-month period ( n = 102). Graduated suction catheters and suction vacuums of < 165 cm H2O were then introduced. Another prospective audit was carried out 3 months later ( n = 60). Results : We found that 24% developed RUL collapse and 4 developed an apical pneumothorax. Following the introduction of graduated catheters and controlled vacuums pressures, a significant reduction in the incidence of RUL collapse, to 7%, was observed ( p < 0.05). Conclusions : We conclude that high negative pressure and deep-suctioning causes RUL collapse in children. Any lobar collapse not only prolongs the child's stay in intensive care, but can be associated with further morbidity which may have a serious implication. By improving suctioning technique this morbidity can be significantly reduced.  相似文献   
8.
9.
10.
It is still unclear whether i.v. immunoglobulins (Ig) can facilitate the reproductive prognosis of women who have suffered recurrent pregnancy loss. We report the results of a multicentre placebo- controlled study on the effect of Ig administration on pregnancy outcome in 46 women who had suffered at least three recurrent miscarriages. All were screened to exclude chromosomal or Mullerian abnormalities, the presence of antinuclear antibodies, lupus anticoagulant (LA) or elevated titres of anticardiolipin antibodies which may have revealed an underlying autoimmune problem. To avoid a selection bias towards ongoing pregnancies, i.v. Ig or placebo were administered between weeks 5 and 7 of gestation for 2 consecutive days as soon as each woman knew she was pregnant and before embryonic heart activity could be detected. A further infusion was administered at week 8 when ultrasonography confirmed an ongoing embryonic development. In all, 68% of the women who received Ig went to term versus 79% of those who received a placebo (not significant), with no significant differences in the pregnancy course or the perinatal outcome. These results suggest either that women with recurrent miscarriages who have no recognized cause of pregnancy loss have a good reproductive prognosis without any treatment or that the emotional care associated with the administration of a placebo can indirectly facilitate the progression of pregnancy.   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