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   561篇
  免费   25篇
  国内免费   2篇
耳鼻咽喉   11篇
儿科学   5篇
基础医学   68篇
口腔科学   38篇
临床医学   54篇
内科学   168篇
皮肤病学   1篇
神经病学   53篇
特种医学   15篇
外科学   78篇
综合类   1篇
预防医学   15篇
眼科学   3篇
药学   41篇
中国医学   2篇
肿瘤学   35篇
  2023年   4篇
  2022年   7篇
  2021年   11篇
  2020年   4篇
  2019年   11篇
  2018年   14篇
  2017年   9篇
  2016年   8篇
  2015年   9篇
  2014年   17篇
  2013年   22篇
  2012年   21篇
  2011年   36篇
  2010年   20篇
  2009年   12篇
  2008年   26篇
  2007年   44篇
  2006年   27篇
  2005年   35篇
  2004年   31篇
  2003年   23篇
  2002年   17篇
  2001年   3篇
  2000年   6篇
  1999年   10篇
  1998年   12篇
  1997年   9篇
  1996年   5篇
  1994年   4篇
  1993年   7篇
  1992年   6篇
  1991年   8篇
  1990年   6篇
  1989年   6篇
  1988年   6篇
  1987年   5篇
  1986年   11篇
  1985年   11篇
  1984年   12篇
  1983年   15篇
  1982年   6篇
  1981年   3篇
  1980年   3篇
  1979年   4篇
  1977年   3篇
  1975年   3篇
  1971年   2篇
  1970年   2篇
  1968年   2篇
  1923年   1篇
排序方式: 共有588条查询结果,搜索用时 31 毫秒
1.
Off-pump surgery was performed in a patient with post-infarction angina complicated with aneurysmal coronary-pulmonary arterial fistula. Epicardial echocardiography localized the artery feeding the fistula in the myocardium, which had not been revealed by visual inspection, palpation, or transesophageal echocardiography. The patient underwent off-pump coronary artery bypass grafting concomitant with aneurysmectomy. The feeding arteries were dissected easily using a Harmonic Scalpel and ligated. The flow in the aneurysm disappeared immediately and aneurysmectomy was performed without bleeding.  相似文献   
2.
A novel enzyme immunoassay of anti-insulin IgG in human serum is described. A serum sample containing anti-insulin IgG was treated with dextran-charcoal at pH 6.0 to remove endogenous insulin and subsequently incubated with dinitrophenyl biotinyl nonspecific rabbit IgG-insulin conjugate. The reaction mixture was further incubated with a rabbit (antidinitrophenyl bovine serum albumin) IgG-coated polystyrene ball to trap the complex formed between anti-insulin IgG and the conjugate. After washing to eliminate nonspecific IgG in the test serum, the polystyrene ball was incubated with dinitrophenyl-L-lysine to elute the complex. The eluate was incubated with an avidin-coated polystyrene ball. Finally, the amount of human anti-insulin IgG in the complex trapped onto the avidin-coated polystyrene ball was measured by incubation with rabbit (antihuman IgG (γ-chain)) Fab'-peroxidase conjugate. This enzyme immunoassay was 1,000-fold more sensitive than the conventional enzyme immunoassay, in which an insulin-bovine serum albumin-coated polystyrene ball was incubated with a serum sample containing anti-insulin IgG and subsequently with rabbit (antihuman IgG (γ-chain)) Fab'-peroxidase conjugate. The principle of the novel enzyme immunoassay can be used to more sensitively measure antibodies for most kinds of haptens and antigens than the conventional enzyme immunoassay.  相似文献   
3.
A 41-year-old Chinese woman was admitted to our hospital with epigastric pain. Computed tomography detected a heterogeneous enhancement tumor fed by the left gastroepiploic artery in the left lower quadrant and cholelithiasis. Excision of the tumor in the greater omentum and cholecystectomy were performed laparoscopically. Histological findings confirmed a diagnosis of hemangiopericytoma with low-grade malignancy. To our knowledge, hemangiopericytoma of the greater omentum is very rare, and only 12 cases were reported in English literature. We report a case of hemangiopericytoma arising in the greater omentum and review the literature.  相似文献   
4.
During the immune response to T cell-dependent antigen, somatic hypermutation (SHM) is introduced into immunoglobulin (Ig) genes. The variable region is the target for SHM and it is here that DNA lesions are introduced and mutations are generated. It has been suggested that error-prone DNA polymerase(s) may play an important role in this mutagenesis phase. Recently, DNA polymerase kappa (Polkappa), which belongs to the Y-family of DNA polymerases, was identified. Since a hot spot of SHMs (RGYW motif) is also a hot spot of mutations by human Polkappa, this enzyme was suggested to be an SHM instigator. In order to address the question whether Polkappa is involved in SHM, we immunized Polkappa-deficient mice and analyzed the SHM of the Ig heavy chain gene. We found that the SHM frequency and spectrum were indistinguishable between the Polkappa knockout mice and control mice. These results suggested that Polkappa is not essential for this process.  相似文献   
5.
In order to assess the impact of variations in stroke care on outcomes, and to make geographic comparisons, the three Community Hospital-Based Stroke Programs in North Carolina, Oregon, and New York, aggregated their data on 4,132 hospitalized stroke patients. Complete demographic data or "Major Profile" were obtained on 2,390 (57.8%) of the 4,132 stroke patients. This includes those patients on whom informed patient and physician consents were obtained during the hospitalization. Of the major profile patients, 1,490 (62.3%) were followed for periods up to one year, 502 (21.0%) were lost to followup and 398 (16.6%) died within the one year followup period. Incomplete demographic data or "Minor Profile" were observed on 1,742 (42.1%) of the 4,132 patients. Minor profile includes those who died before comprehensive interviews were completed or those for whom informed consent for an interview could not be obtained. Of the minor profile group, 813 (46.7%) died in hospital, and 929 (53.3%) were alive when discharged from the hospital. This paper, which describes the programs, data collection procedures, and study cases, also highlights specific issues on stroke diagnosis, risk factors associated with stroke, and the influence of interventions on stroke outcomes. We conclude that: 1) the merging of data on hospitalized stroke cases from rural and urban hospitals in geographically distinct regions can be used in the study of stroke diagnosis, the use of diagnostic tests, and the effect of interventions on stroke outcomes; and 2) these data are consistent with the hypothesis that part of the national decline in mortality from stroke is due to a decline in stroke severity.  相似文献   
6.
PurposeThe aim of this study was to assess the association between the implementation of abdominal angiography and outcome among pediatric patients with blunt splenic or hepatic injury.MethodsThis was a retrospective observational study, with a study period of 14 years, from January 2004 to December 2017. Blunt-trauma patients with splenic or hepatic injury who were less than 19 years old were included in this study. We used propensity-score-(PS) matching analysis to assess the relationship between abdominal angiography and in-hospital mortality.ResultsIn total, 639 patients were eligible for analysis, with 257 patients included in the abdominal-angiography group and 382 patients in the no-abdominal-angiography group. After PS matching, 224 patients from each group were selected. In the PS matched patients, in-hospital mortality was lower in the abdominal-angiography group than in the no-abdominal-angiography group (4.9% vs. 11.2%, odds ratio 0.416, 95% confidence interval 0.177–0.903).ConclusionIn this population, the implementation of abdominal angiography was significantly associated with lower in-hospital mortality among pediatric patients with blunt splenic or hepatic injury compared with nonimplementation of abdominal angiography.Type of studyPrognosis study.Level of evidenceIII  相似文献   
7.
Hess DC  Demchuk AM  Brass LM  Yatsu FM 《Neurology》2000,54(4):790-796
Statins represent a promising class of agents to prevent stroke. In randomized trials of middle-aged patients with coronary artery disease, statins reduce the incidence of stroke. The reduction in stroke may not be solely related to cholesterol or low-density lipoprotein reduction but may involve nonsterol mechanisms effects on endothelial cells, macrophages, platelets, and smooth muscle cells. Statins also reduce the size of cerebral infarction in a murine stroke model, suggesting a neuroprotective effect. The best current evidence for stroke prevention is with pravastatin and simvastatin. Pravastatin reduces the risk of stroke in patients with coronary artery disease and average cholesterol levels; simvastatin reduces the risk of the combined endpoint of stroke and transient ischemic attack in hypercholesterolemic patients with coronary artery disease. Future studies of statins are needed in stroke populations, particularly the elderly.  相似文献   
8.
Several factors such as proteinuria and renal fibrosis may be important in the progression of many forms of chronic renal diseases. The purposes of the current study were to investigate the progressive renal failure of the rats with surgical renal mass reduction (RMR) and the effect of the angiotensin-converting enzyme (ACE) inhibitor, lisinopril, and to document correlation of several factors associated with progressive renal failure. Rats were subtotal (5/6) nephrectomized by resection of the renal poles and sham-operated. The functional, histological and haematological changes of the rats were studied for up to 10 weeks. After 2 weeks of RMR, oral administration of lisinopril (10 mg kg(-1) per day) was performed for 8 weeks. RMR resulted in progressive renal failure with proteinuria, monocyte/macrophage (ED1+) infiltration, anaemia as assessed by haemoglobin and haematocrit (Htc), renal hypertrophy as assessed by left kidney to body weight ratio (BKW/BW), and renal fibrosis as assessed by glomerular lesions and tubulointerstitial changes. Lisinopril exhibited renoprotection with antiproteinuric effect and inhibition of monocyte/macrophage (ED1+) infiltration. However, beneficial effect of lisinopril on anaemia was not observed. At 10 weeks after surgery, severity of proteinuria positively correlated with plasma creatinine (Pcr), BKW/BW, histological damage, and systolic blood pressure, and negatively correlated with haemoglobin. Severity of tubulointerstitial changes positively correlated with Pcr and blood urea nitrogen, and negatively correlated with haemoglobin and Htc. Moreover, monocyte/macrophage (ED1+) infiltration positively correlated with severity of proteinuria and tubulointerstitial changes. These findings strongly support that proteinuria, monocyte/macrophage infiltration and renal fibrosis appear to play principal roles in the progressive renal failure with anaemia and renoprotection of ACE inhibition may be mediated by multiple actions of ACE inhibitor. The present study confirms that rats with RMR is useful to explore target molecules for renoprotective drugs and evaluate renoprotective effect of new molecular entities.  相似文献   
9.
This study was designed to compare prebypass haemodynamics under total intravenous anaesthesia (TIVA) using midazolam-fentanyl (group M) and propofol-fentanyl (group P) combinations. Sixteen adult patients undergoing CABG were studied with patients in group M and P (n = 8 each) given intravenous midazolam 0.1 mg.kg-1.h-1 and propofol 4 mg.kg-1.h-1 with fentanyl 25 micrograms.kg-1 until sternotomy, respectively. Following induction of anaesthesia, cardiac index and heart rate decreased significantly (30% and 20% in both groups, p < 0.05) these variables returned to baseline on completion of sternotomy. In addition, in group P mean arterial pressure decreased significantly (about 15%) following induction and there were no ischaemic signs. Overall for MAP there was no significant difference between the two groups. LVSWI and RVSWI were reduced by around 25% in both groups. Only the change in LVSWI reached statistical significance (p < 0.05). This reduction may have exert a caridioprotectant action by decreasing myocardial oxygen consumption. We conclude that both TIVA techniques represent an acceptable anaesthetic regimen for use in cardiac anaesthesia.  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