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   294篇
  免费   20篇
  国内免费   4篇
耳鼻咽喉   4篇
儿科学   5篇
妇产科学   11篇
基础医学   54篇
口腔科学   9篇
临床医学   21篇
内科学   96篇
神经病学   23篇
特种医学   6篇
外科学   24篇
综合类   2篇
预防医学   16篇
眼科学   12篇
药学   10篇
中国医学   3篇
肿瘤学   22篇
  2024年   1篇
  2023年   6篇
  2022年   4篇
  2021年   25篇
  2020年   9篇
  2019年   11篇
  2018年   12篇
  2017年   8篇
  2016年   4篇
  2015年   6篇
  2014年   18篇
  2013年   8篇
  2012年   19篇
  2011年   22篇
  2010年   7篇
  2009年   5篇
  2008年   16篇
  2007年   20篇
  2006年   11篇
  2005年   14篇
  2004年   13篇
  2003年   9篇
  2002年   12篇
  2001年   7篇
  2000年   5篇
  1999年   3篇
  1998年   1篇
  1997年   3篇
  1996年   2篇
  1995年   2篇
  1994年   2篇
  1992年   1篇
  1991年   1篇
  1990年   5篇
  1988年   4篇
  1987年   6篇
  1986年   1篇
  1984年   1篇
  1982年   3篇
  1979年   2篇
  1978年   1篇
  1976年   3篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
  1968年   1篇
排序方式: 共有318条查询结果,搜索用时 31 毫秒
1.
2.
The enzymatic basis of the respiratory burst induced by phorbol myristate acetate in elicited peritoneal macrophages of the guinea-pig has been studied. The following evidence suggests that a membrane-bound oxidase that preferentially uses NADPH as substrate is the main enzyme responsible for activation of the oxidative metabolism: (1) The supernatant of postnuclear fractions of resting macrophages oxidises NADH and NADPH with formation of O. The activity with both substrates is very low and does not change in the supernatant obtained from activated cells. (2) The cell-free particles of resting macrophages also oxidise both NADH and NADPH with formation of O. The activity of the cell-free particles from activated macrophages does not change when NADH is the substrate. By contrast, the activity of the cell-free particles from activated cells is markedly increased when NADPH is the substrate. (3) In cell-free particles from activated macrophages the Km for NADPH is about one order of magnitude lower than that for NADH and the Vmax with NADPH is double that with NADH. (4) The NADPH oxidase of cell-free particles is insensitive to azide, cyanide, antimycin A and rotenone and is sensitive to the sulphydryl reagent PCMB. All these drugs have the same effect on the respiratory response of intact macrophages. (5) A direct correlation is found between the degree of activation of the respiratory metabolism of intact macrophages and the extent of activation of the NADPH oxidase. A new approach designed to measure the activity of the oxidase soon after the activation of the enzyme has taken place, shows that the NADPH oxidase can account for the respiratory burst of intact macrophages.  相似文献   
3.
E-selectin, an adhesion molecule of the selectin family, is involved in leukocyte adhesion to the endothelium and in the cellular immunological reactions. Expression of this molecule, in fact, is physiologically absent, but it becomes evident on sinusoidal lining cells during inflammatory liver disease. The aim of this study was to evaluate the behavior of E-selectin in chronic hepatitis C (CH-C) patients with persistently normal transaminase in comparison to patients with CH-C and elevated transaminase, and its changes during alpha-interferon therapy. Immunohistochemical localization of E-selectin was also performed on liver tissue specimens of both groups. Fifty-eight subjects were divided into 3 groups: group A included 18 patients with CH-C and persistently normal transaminase; group B 20 patients with CH-C and persistently elevated transaminase levels and group C included 20 healthy subjects, representing the control group. The first two groups were treated with r-IFN at a dose of 6 MU 3 times a week for 3 months and followed-up with 3 MU 3 times a week for another 3 months. Serum baseline values of E-selectin in groups A and B were significantly higher than those in group C (P < 0.04), but there was no difference between groups A and B. Furthermore, there was a trend toward higher E-selectin values as histological severity increased (r = 0.69; P < 0.0001). Post-treatment E-selectin serum values showed a moderate decrease in both groups, but only among responder patients; while E-selectin levels were unchanged in non responders. Immunohistochemical localization showed no staining for E-selectin in normal liver specimens, while there was a quite similar staining for E-selectin in the two groups of patients. In conclusion, this study shows that serum E-selectin levels in patients with CH-C and persistently normal transaminase are higher than in controls and they are associated with severity of liver disease. Liver of these patients express E-selectin molecules, suggesting an activation of the immune system almost identical to that of patients with CH-C and elevated transaminase. In both groups only responder patients showed a moderate decrease below baseline serum values.  相似文献   
4.
Non-neoplastic jaw cyst (NJC) is one of the most common lesions in oral cavity, but there are only few detailed and extended epidemiological data based on the 2017 WHO classification. The aim of this study was to perform an epidemiological analysis of all NJCs treated from 1990 to 2019 at the Marche Polytechnic University, and to compare these data with those published in the literature. This retrospective study considered 2060 patients treated from 1990 to 2019. The NJCs were classified according to the 2017 WHO classification, and the main clinicopathological variables were analysed (sex, age, diagnosis, site of onset, size, and recurrences). Of 2150 total lesions, there were 2095 primary cysts and 55 recurrences; men are more frequently affected than women (M/F ratio of 1.73:1). The mean age of occurrence was 46.6 years, with a peak of frequency in the fifth decade. The mandible was more frequently involved than the maxilla, with a mean size of 1.9 cm. Radicular cyst was the most frequently diagnosed cyst (56.6%), followed by dentigerous cyst (23.4%) and odontogenic keratocyst (12.9%). This is the first epidemiological study on NJCs in the Italian population according to 2017 WHO classification.  相似文献   
5.
6.
The clinical value of early exercise stress testing (EST) after coronary stenting to predict long-term clinical outcomes is unknown. Of 1,000 unselected patients who underwent coronary stenting, 446 random patients underwent early EST the day after intervention. Clinical long-term outcomes (41 +/- 20 months) were correlated with normal (n = 314 [70%]) or positive (n = 102 [23%]) EST results. Patients with inconclusive test results (n = 30 [7%]) were excluded from the analysis. Overall mortality was significantly higher in patients with positive EST results (9.3% vs 3.9%, p = 0.04). Major adverse cardiac events and cardiac mortality also tended to be higher in patients with positive stress test results (45.4% vs 35.4%, p = 0.08, and 4.1% vs 1.1%, p = 0.05, respectively). Patients with the combination of positive stress test results and incomplete revascularization appeared to be the group at highest risk for major adverse cardiac events (47.1% vs 33.3% for patients with normal stress test results and complete revascularization, p = NS). Negative stress test results reduced (odds ratio 0.329, 95% confidence interval 0.120 to 0.905, p = 0.031) and a lower ejection fraction increased (odds ratio 0.942, 95% confidence interval 0.897 to 0.989, p = 0.017) the risk for death. In conclusion, an early stress test after coronary stenting provides important prognostic information. Positive stress test results, especially in combination with incomplete revascularization, are associated with higher mortality, a trend toward more repeat revascularization procedures, and higher risk for major adverse cardiac events.  相似文献   
7.
The effects of dihydroergocriptine (DHECP), a dihydrogenated ergot alkaloid with dopaminergic agonistic and alpha-adrenergic antagonistic properties, were studied in 22 women with PRL-secreting microprolactinomas and compared with those recorded in 36 previously studied patients treated with bromocriptine (BRC). After acute administration of 5 mg DHECP, orally, serum PRL decreased by 61 +/- 18% (+/- SD); only 1 patient was unresponsive. The nadir was reached at 300 min. Long term treatment with increasing DHECP doses caused a progressive PRL fall from 125 +/- 142 (+/- SD) to 81 +/- 159 micrograms/L after 1 week of a 3 mg twice daily regimen, to 64 +/- 88 micrograms/L after 1 week of 5 mg twice daily, 46 +/- 57 micrograms/L after 1 week of 10 mg twice daily, and 28 +/- 34 to 33 +/- 45 micrograms/L throughout 9 months of treatment with 10 mg DHECP 3 times daily. Seventy-seven percent of patients had normal serum PRL levels during chronic treatment. All women, including those with supranormal serum PRL levels, resumed regular menses, and 16 had ovulatory cycles; 1 woman became pregnant. Galactorrhea disappeared in all. During treatment the PRL response to TRH, initially absent in all patients, became positive in 10. In 7 patients, after DHECP treatment for 9 months, high definition computed tomographic scan no longer showed the focal lesions initially seen. After drug withdrawal, serum PRL increased again in all except 1 patient. Two patients had regular menses for 6 months, and 3 still had no adenoma imaged by high definition computed tomography. In BRC-treated patients the serum PRL changes and clinical results were very similar to those in the DHECP-treated patients, except for the persistence of normal serum PRL levels in 4 patients after drug withdrawal. On the other hand, side-effects were negligible during DHECP treatment, but remarkable during BRC. Systolic and diastolic blood pressures decreased by only 5.4 and 3.0 mm Hg, respectively, after acute 5 mg DHECP administration, but decreased by 12.8 and 14 mm Hg after acute 2.5 mg BRC administration. Orthostatic hypotension and peripheral vasomotor phenomena occurred in the long term DHECP treated patients except one, but they occurred in 9 and 3 of those treated with BRC, respectively. Gastric discomfort or mild nausea occurred in 12 DHECP-treated patients, while mild or severe nausea or vomiting were observed in 18, 11, and 2 of those taking BRC, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
8.
Assessing cytomegalovirus (CMV)-specific cell-mediated immunity (CMI) represents an appealing strategy for identifying transplant recipients at risk of infection. In this study, we compared two gamma interferon-releasing assays (IGRAs), Quantiferon-CMV and CMV enzyme-linked immunosorbent spot (ELISPOT), to determine the ability of each test to predict protective CMV-specific T-cell responses. Two hundred twenty-one Quantiferon-CMV and ELISPOT tests were conducted on 120 adult kidney transplant recipients (KTRs), including 100 CMV-seropositive transplant recipients (R+) and 20 CMV-seronegative transplant recipients of a CMV-positive donor (D+/R). As a control cohort, 39 healthy adult subjects (including 33 CMV-seropositive and 6 CMV-seronegative subjects) were enrolled. CMV IgG serology was used as a reference for both tests. In the CMV-seropositive individuals, the ELISPOT and Quantiferon-CMV assays provided 46% concordance with the serology, 12% discordance, 18% disagreement between ELISPOT or Quantiferon-CMV and the serology, and 24% gray areas when one or both tests resulted in weak positives. None of the CMV-seronegative subjects showed detectable responses in the ELISPOT or the Quantiferon-CMV test. In transplant recipients, both the ELISPOT and Quantiferon-CMV assays positively correlated with each other and negatively correlated with CMV DNAemia in a significant way (P < 0.05). During the antiviral prophylaxis, all 20 D+/R KTRs we examined displayed undetectable Quantiferon-CMV and ELISPOT results, and there was no evidence of CMV seroconversion. The receiving operator curve (ROC) statistical analysis revealed similar specificities and sensitivities in predicting detectable viremia (areas under the curve [AUC], 0.66 and 0.62 for Quantiferon-CMV and ELISPOT, respectively). ELISPOT and Quantiferon-CMV values of >150 spots/200,000 peripheral blood mononuclear cells (PBMCs) and >1 to 6 IU gamma interferon (IFN-γ) were associated with protection from CMV infection (odds ratios [OR], 5 and 8.75, respectively). In transplant recipients, the two tests displayed similar abilities for predicting CMV infection. Both the ELISPOT and Quantiferon-CMV assays require several ameliorations to avoid false-negative results.  相似文献   
9.
Statement of problemWith the aging population, an increasing number of patients will require removable dental prostheses. Despite the recent public efforts to improve oral healthcare, knowledge of hygiene procedures for removable dental prostheses is sparse.PurposeThe purpose of this cross-sectional study was to determine, through questionnaires, the level of awareness and education of home hygiene procedures among elderly Italian individuals wearing removable dental prostheses and to correlate self-reported hygiene habits and prosthesis cleanliness, as determined by a clinical examination.Material and methodsA cross-sectional study was performed by questionnaires administered by a dental hygienist to patients attending the dental clinics (prosthodontic and periodontology clinical units) at San Paolo Hospital of Milan from January 2014 to October 2015 and who volunteered to participate. The questionnaire included demographic data and oral hygiene habits. Each participant received an intraoral and prosthesis examination performed by the same dental hygienist. The cleanliness of the removable dental prosthesis was classified according to a 3-point scoring system. Categorical variables were expressed as a percentage of study participants and compared by using the χ2 test, while, for the statistical correlations between continuous and categorical variables, the point-biserial correlation calculator was used (α=.05).ResultsQuestionnaires were collected from 161 study participants: 92 women (mean ±standard deviation age: 76 ±7.59 years; range: 65-93 years) and 69 men (mean ±standard deviation age: 74 ±6.31 years; range: 65-86 years). A total of 239 prostheses were considered. A significant correlation was found between older participants, older removable dental prostheses, and reduced prosthesis cleanliness, correlating age ranges of participants as well as of removable dental prostheses with the degrees of prosthesis cleanliness (P=.001 and P=.004, respectively). Half the study participants (n=81; 50.3%) reported prosthesis removal during the night, while the others reported sleeping with the prosthesis in place. Some study participants (n=32; 19.9%) reported that they had never received instructions about how to clean the prosthesis. Mechanical brushing with toothbrush and toothpaste was the most common cleaning method (n=47; 29.2%), while the recommended combined cleaning method based on both mechanical brushing and immersion in dental cleanser was applied by 34 (21.1%) study participants. A similar number (n=25; 15.5%) reported at least 1 episode of denture-related stomatitis.ConclusionsIn the analyzed cohort, patient attitude and habits toward home procedures for denture hygiene resulted in poor prosthesis cleanliness. Most individuals used a toothbrush and toothpaste to clean their device, although combining mechanical and chemical cleaning is typically reported to be the optimal method.  相似文献   
10.
AIMS: To investigate the efficacy and outcome of emergency percutaneous coronary interventions (PCI) in patients with stent thrombosis. METHODS AND RESULTS: Between 1995 and 2003, 6058 patients underwent bare-metal stent implantation, of which 95 (1.6%) patients suffered from stent thrombosis. The timing of stent thrombosis was acute in 10 (11%), subacute in 61 (64%), and late in 24 (25%) patients. Procedural and clinical outcomes of emergency PCI for treatment of stent thrombosis were investigated. Emergency PCI was successful in 86 (91%), complicated by death in 2 (2%), and coronary artery bypass grafting in 2 (2%) patients. Myocardial infarction occurred in 77 (81%) patients with a peak creatine kinase level of 1466+/-1570 U/L. Left ventricular ejection fraction declined from 0.54+/-0.19 prior to 0.48+/-0.16 (P<0.05) at the time of stent thrombosis after emergency PCI. A 6 month major adverse clinical events comprised death (11%), reinfarction (16%), and recurrent stent thrombosis (12%) after emergency PCI. Multivariable logistic regression analysis identified the achievement of TIMI 3 flow (OR=0.1, CI 95% 0.01-0.54, P<0.001) and diameter stenosis <50% (OR=0.06, CI 95% 0.01-0.32, P<0.001) during emergency PCI to be independently associated with a reduced risk of cardiac death. Recurrent stent thrombosis was independently predicted by the omission of abciximab (OR=4.3, CI 95% 1.1-17.5). CONCLUSION: Emergency PCI for treatment of stent thrombosis effectively restores vessel patency and flow. Patients presenting with stent thrombosis are at risk for recurrent myocardial infarction and recurrent stent thrombosis.  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