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   190篇
  免费   16篇
  国内免费   7篇
耳鼻咽喉   1篇
儿科学   1篇
妇产科学   3篇
基础医学   25篇
临床医学   8篇
内科学   93篇
神经病学   12篇
特种医学   8篇
外科学   28篇
预防医学   8篇
眼科学   2篇
药学   9篇
肿瘤学   15篇
  2022年   1篇
  2021年   3篇
  2020年   4篇
  2019年   4篇
  2018年   3篇
  2017年   1篇
  2016年   7篇
  2015年   3篇
  2014年   10篇
  2013年   14篇
  2012年   13篇
  2011年   9篇
  2010年   6篇
  2009年   3篇
  2008年   7篇
  2007年   11篇
  2006年   7篇
  2005年   5篇
  2004年   8篇
  2003年   9篇
  2002年   11篇
  2001年   2篇
  2000年   8篇
  1999年   4篇
  1998年   1篇
  1997年   5篇
  1996年   1篇
  1995年   5篇
  1994年   2篇
  1993年   1篇
  1992年   5篇
  1991年   4篇
  1990年   5篇
  1989年   1篇
  1988年   10篇
  1987年   4篇
  1986年   3篇
  1985年   3篇
  1984年   5篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
排序方式: 共有213条查询结果,搜索用时 15 毫秒
1.
2.
PURPOSE: The clinical course of polycythemia vera is often complicated by thrombosis as well as by the possible transition to myeloid metaplasia with myelofibrosis or acute myeloid leukemia. The aim of this study was to assess the rate of these complications in subjects receiving currently recommended treatments. PATIENTS AND METHODS: Overall, 1,638 patients from 12 countries were enrolled onto a large, prospective multicenter project aimed at describing the clinical history of polycythemia vera for the following outcomes: survival, the cumulative rate of cardiovascular death and thrombosis, the cumulative rate of leukemia, myelodysplasia, and myelofibrosis. The mean duration of the disease at entry and the duration of the follow-up were 4.9 and 2.7 years, respectively. RESULTS: The overall mortality rate of 3.7 deaths per 100 persons per year resulted from a moderate risk of cardiovascular death and a high risk of death from noncardiovascular causes (mainly hematologic transformations). Age older than 65 years and a positive history of thrombosis were the most important predictors of cardiovascular events. Antiplatelet therapy, but not cytoreductive treatment, was significantly associated with a lower risk of cardiovascular events. We found a consistent association between age and risk of leukemia, and between duration of the disease with risk of myelofibrosis. CONCLUSION: The European Collaboration on Low-Dose Aspirin in Polycythemia Vera study documents that large international collaborative studies are feasible in this field, in which few epidemiologic data are available. The persistently high mortality rate from hematologic malignancies characterizes the unmet therapeutic need of polycythemic patients and suggests a priority for future studies in this disease.  相似文献   
3.
Most cardiopulmonary diseases share at least one symptom with pulmonary embolism (PE). The aim of this study was to identify the most common acute causes of dyspnea, chest pain, fainting or palpitations, which diagnostic procedures were performed and whether clinicians investigate them appropriately. An Italian multicenter collaboration gathered 17,497 Emergency Department (ED) records of patients admitted from January 2007 to June 2007 in six hospitals. A block random sampling procedure was applied to select 800 hospitalised patients. Results of the overall 17,497 patients were obtained by weighting sampled cases according to the probability of the randomisation block variables in the whole population. The case-mix of enrolled patients was assessed in terms of cardiopulmonary symptoms, and the prevalence of acute disorders. The actual performance of procedures was compared with a measure of their accuracy as expected in the most common clinical presentations. PE occurred in less than 4% of patients with cardiopulmonary symptoms. Acute heart failure, pneumonia and chronic obstructive pulmonary disease exacerbation were the most likely diagnoses in patients with dyspnea. Acute myocardial infarction was present in roughly 10% of patients with chest pain. Atrial fibrillation was the prevalent diagnosis in patients with palpitations. Echocardiography, computed tomographic pulmonary angiography, perfusion lung scan, D-dimer test and B-type natriuretic peptide were performed less than expected from their accuracy. Diagnostic strategies, starting from non-specific symptoms and coping with the eventuality of PE, are likely to benefit from an increased awareness of the examination’s accuracy in discriminating among several competing hypotheses, rather than in testing the single PE suspicion.  相似文献   
4.
Beta-thromboglobulin (beta TG) plasma levels were measured by radioimmunoassay in 14 patients with acute myocardial infarction (MI), in 13 with myocardial ischemia and recurrent episodes of angina and in 14 subjects with a past history of MI. Increased beta TG plasma values were observed in patients with acute MI and with myocardial ischemia whereas subjects with a past history of MI showed results not significantly different from normal subjects. Daily measurements in acute MI showed in five cases a second peak of beta TG values which suggests the occurrence of a deep vein thrombosis. The increased platelet consumption in MI was not related with the extent of the necrosis. We suggest, therefore, that platelet activation is associated with myocardial ischemia rather than necrosis.  相似文献   
5.
According to strict clinical, hematological and morphological criteria, the Philadelphia (Ph) chromosome negative chronic myeloproliferative disorders essential thrombocythemia (ET), polycythemia vera (PV), and agnogenic myeloid (megakaryocytic/granulocytic) metaplasia (AMM) or idiopathic myelofibrosis (IMF) are three distinct disease entities with regard to clinical manifestations, natural history and outcome in terms of life expectancy. As clonality studies have clearly demonstrated that fibroblast proliferation in AMM, as well as in many other conditions such as advanced stages of Ph(+)-essential thrombocythemia, Ph(+)-granulocytic leukemia, and Ph(-)-polycythemia vera, is polyclonal indicating that myelofibrosis is secondary to the megakaryocytic granulocytic metaplasia in these various conditions, AMM is illogically labeled as IMF. As abnormal megakaryocytic granulocytic metaplasia is the essential feature preceding the early prefibrotic stage of AMM, the term essential megakaryocytic granulocytic metaplasia (EMGM) can readily be used to characterize this condition more appropriately at the biological level. Clinical, hematological and morphological characteristics, in particular megakaryocytopoiesis and bone marrow cellularity, reveal diagnostic features, which enable a clear-cut distinction between ET, PV and EMGM or classical IMF. The characteristic increase and clustering of enlarged megakaryocytes with mature cytoplasm and multilobulated nuclei and their tendency to cluster in a normal or only slightly increased cellular bone marrow represent the hallmark of ET. The characteristic increase and clustering of enlarged mature and pleiomorphic megakaryocytes with multilobulated nuclei and proliferation of erythropoiesis in a moderate to marked hypercellular bone marrow with hyperplasia of dilated sinuses are the specific diagnostic features of untreated PV. EMGM, including the early prefibrotic stages as well as the various myelofibrotic stages of classical IMF appear to be a distinct neoplastic dual proliferation of abnormal megakaryopoiesis and granulopoiesis. The histopathology of the bone marrow in prefibrotic EMGM and in classical IMF is dominated by atypical, enlarged and immature megakaryocytes with cloud-like immature nuclei, which are not seen in ET and PV at diagnosis and during follow-up. Myelofibrosis in ET, PV and EMGM is graded into: no reticulin fibrosis (MF0), early reticulin fibrosis (MF1), advanced reticulin sclerosis with minor or moderate collagen fibrosis (MF2) and advanced collagen fibrosis with osteosclerosis (MF3). Myelofibrosis is not a feature of ET at diagnosis and during long-term follow-up. Myelofibrosis may be present in a minority of PV-patients at diagnosis and usually becomes apparent during long-term follow-up in the majority of PV-patients. Myelofibrosis secondary to the abnormal megakaryocytic and granulocytic myeloproliferation constitutes a prominent feature in the majority of EMGM/IMF at time of diagnosis and usually progresses more or less rapidly during the natural history of the disease. Life expectancy is normal in ET, normal during the 1st ten years and compromised during the 2nd ten years follow-up in PV, but significantly shortened in the prefibrotic stage of EMGM as well as in the various myelosclerotic stages of classical IMF. First line treatment options in prospective randomized clinical trials of newly diagnosed MPD-patients are control of platelet function with low-dose aspirin versus reduction of platelet count with anagrelide, interferon or hydroxyurea in ET; control of platelet and erythrocyte counts by interferon alone versus bloodletting plus hydroxyurea on indication in PV; interferon versus no treatment in the early stages of EMGM; a wait and see strategy in the fibrotic stages of EMGM or classical IMF with favorable prognostic factors, and bone marrow transplantation in classical IMF with poor prognostic factors at presentation or during short-term follow-up.  相似文献   
6.

Objectives and design

We investigated the effect of balanced (BS) and unbalanced (UBS) solutions in the absence or presence of hydroxyethyl starch (HES) on neutrophil functionality, evaluating the release of matrix metalloproteinase (MMP)-9, myeloperoxidase (MPO), and MMP-8.

Materials and methods

Neutrophils were isolated by gradient centrifugation and dextran sedimentation and incubated in BS or UBS without or with HES, in the absence or presence of Interleukin-8 (IL-8) or Lipopolysaccharide (LPS). MMP-9, MPO, and MMP-8 were assayed by commercially available ELISA kits.

Results

There was not any influence of volume replacement solutions on the release of the enzymes from resting neutrophils. After IL-8 stimulation, the release of MMP-9 was higher in BS than in UBS or RPMI-1640, whereas HES enhanced its release regardless of the composition. After LPS stimulation, the release of MMP-9 was higher in both UBS and BS than RPMI-1640, but HES brought its release back to physiological conditions. No difference was found in the release of MPO and MMP-8 after stimulation with IL-8 or LPS.

Conclusion

Volume replacement solutions might have an impact on the release of MMP-9 depending on the inflammatory milieu, suggesting that the use of balanced or unbalanced solutions is not a neutral choice.  相似文献   
7.
The optimal timing of surgery in case of synchronous presentation of colorectal cancer and liver metastases is still under debate. Staged approach, with initial colorectal resection followed by liver resection (LR), or even the reverse, liver-first approach in specific situations, is traditionally preferred. Simultaneous resections, however, represent an appealing strategy, because may have perioperative risks comparable to staged resections in appropriately selected patients, while avoiding a second surgical procedure. In patients with larger or multiple synchronous presentation of colorectal cancer and liver metastases, simultaneous major hepatectomies may determine worse perioperative outcomes, so that parenchymal-sparing LR should represent the most appropriate option whenever feasible. Mini-invasive colorectal surgery has experienced rapid spread in the last decades, while laparoscopic LR has progressed much slower, and is usually reserved for limited tumours in favourable locations. Moreover, mini-invasive parenchymal-sparing LR is more complex, especially for larger or multiple tumours in difficult locations. It remains to be established if simultaneous resections are presently feasible with mini-invasive approaches or if we need further technological advances and surgical expertise, at least for more complex procedures. This review aims to critically analyze the current status and future perspectives of simultaneous resections, and the present role of the available mini-invasive techniques.  相似文献   
8.
Introduction Nonalcoholic fatty liver disease (NAFLD) has been described in adult GH deficiency syndrome. Furthermore, chronic liver disease can be associated with significant changes in levels of IGF‐I, GH‐binding protein (GHBP), IGF‐binding proteins (IGFBPs) and acid‐labile subunit (ALS). However, the effect of liver steatosis on the GHBP production has not been investigated yet. Aim of the study To explore whether GH secretion and/or levels of IGF‐I, IGFBP‐3, ALS and GHBP could be altered in obese patients in relation to the presence of liver steatosis. Materials and methods A total of 115 obese patients (BMI > 30) were enrolled in the protocol (65 patients with liver steatosis and 50 age‐ and BMI‐matched controls). In all patients, the following parameters were studied: serum levels of glucose, insulin, the HOMA index, IGF‐I, GHBP, IGFBP‐3, ALS and GH after GHRH and arginine stimulation test. Results As expected, patients with NAFLD had blood glucose, insulin, HOMA‐R significantly higher than controls, indicating a more severe insulin‐resistance state in NAFLD. Furthermore, patients with NAFLD had higher levels of GHBP and IGFBP‐3 and lower GH peak and IGF‐I levels as compared to controls. No difference was found in ALS levels between the groups. In a multivariate analysis, GHBP was positively associated with hepatic steatosis while IGF‐1 was negatively associated with hepatic steatosis. Conclusions This study demonstrates that in patients with NAFLD, the GHBP levels are increased, and that the GH/IGF‐I axis is significantly altered probably leading to reduced IGF‐I bioavailability at tissue level.  相似文献   
9.
Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are inflammatory rheumatic diseases common in people over the age of 50 years. Herein, we report 10 cases of previously healthy subjects who developed GCA/PMR within 3 months of influenza vaccination (Inf-V). A Medline search uncovered additional 11 isolated cases of GCA/PMR occurring after Inf-V. We discuss the role of individual susceptibility, the potential function of immune adjuvants as triggers of autoimmunity post-vaccination, and the correlation of our observation with the 'ASIA' syndrome, i.e. autoimmune/inflammatory syndrome induced by adjuvants and including post-vaccination phenomena.  相似文献   
10.
BACKGROUND: Chronic myeloid leukemia arises from a somatic mutation in a pluripotent stem cell. It generally terminates with a blastic crisis (BC). One third of BC are lymphoid, and most have a pre-B phenotype. Few cases of T-lymphoid BC have been reported. Here we describe a lymph node blast crisis mimicking T-immunoblastic lymphoma. METHODS: Bone marrow and lymph nodes were histologically examined by standard methods and by an immunoperoxidase technique. Cytogenetic studies were also performed on lymph node and blood cells. Analysis of T-cell receptor genes and BCR rearrangements were performed on DNA extracted from both frozen bone marrow and lymph-node cells. RESULTS: Lymph-node histology showed an infiltration by large lymphoid blasts, consistent with a diagnosis of immunoblastic lymphoma. Blast cells were CD2, CD7, TDT positive, and negative for myeloid and mature lymphoid antigens. The Ph1 chromosome was found in both bone marrow and lymph-node cells. BCR rearrangement was found in the DNA from both bone marrow and lymph-node cells. TCR genes were not rearranged. DISCUSSION: The present study provides strong evidence that the lymph-node blast crisis of CML can assume the morphological appearance of immunoblastic lymphoma and may retain the immunological phenotype and genetic features of early T cells with BCR rearrangements.  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