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   331篇
  免费   14篇
耳鼻咽喉   8篇
儿科学   11篇
妇产科学   11篇
基础医学   41篇
口腔科学   5篇
临床医学   14篇
内科学   46篇
皮肤病学   3篇
神经病学   4篇
特种医学   8篇
外科学   41篇
综合类   18篇
预防医学   11篇
眼科学   58篇
药学   13篇
肿瘤学   53篇
  2023年   2篇
  2022年   4篇
  2021年   5篇
  2019年   4篇
  2018年   9篇
  2017年   6篇
  2016年   8篇
  2015年   6篇
  2014年   6篇
  2013年   23篇
  2012年   15篇
  2011年   14篇
  2010年   7篇
  2009年   8篇
  2008年   13篇
  2007年   26篇
  2006年   27篇
  2005年   17篇
  2004年   24篇
  2003年   12篇
  2001年   4篇
  2000年   4篇
  1999年   4篇
  1997年   4篇
  1996年   4篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   5篇
  1991年   3篇
  1990年   4篇
  1989年   4篇
  1987年   3篇
  1986年   6篇
  1985年   7篇
  1984年   4篇
  1983年   3篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1979年   9篇
  1978年   3篇
  1977年   3篇
  1975年   2篇
  1973年   1篇
  1972年   5篇
  1971年   9篇
  1970年   2篇
  1969年   1篇
  1932年   1篇
排序方式: 共有345条查询结果,搜索用时 15 毫秒
1.
Serum copper and iron in ischemic heart disease   总被引:1,自引:0,他引:1  
  相似文献   
2.
Tetrahydrocortisol, -cyclodextrin tetradecasulfate, and minocycline used alone or in combination are not very cytotoxic toward EMT-6 mouse mammary tumor cells growing in monolayer. Tetrahydrocortisol (100 M, 24 h) and -cyclodextrin tetradecasulfate (100 M, 24 h) protected EMT-6 cells from the cytotoxicity of CDDP, melphalan, 4-hydroperoxycyclophosphamide, BCNU, and X-rays under various conditions of oxygenation and pH. Minocycline (100 M, 24 h) either had no effect upon or was additive with the antitumor alkylating agents or X-rays in cytotoxic activity toward the EMT-6 cells in culture. The combination of the three modulators either had no effect upon or was to a small degree protective against the cytotoxicity of the antitumor alkylating agents or X-rays. The Lewis lung carcinoma was chosen for primary tumor growth-delay studies and tumor lung-metastases studies. Tetrahydrocortisol and -cyclodextrin tetradecasulfate were given in a 1:1 molar ratio by continuous infusion over 14 days, and minocycline was given i.p. over 14 days, from day 4 to day 18 post tumor implantation. The combination of tetrahydrocortisol/-cyclodextrin tetradecasulfate diminished the tumor growth delay induced by CDDP and melphalan and produced modest increases in the tumor growth delay produced by cyclophosphamide and radiation. Minocycline co-treatment increased the tumor growth delay produced by CDDP, melphalan, radiation, bleomycin, and, especially cyclophosphamide, where 4 of 12 animals receiving minocycline (14×5mg/kg, days 4–18) and cyclophosphamide (3×150 mg/kg, days, 7, 9, 11) were long-term survivors. The 3 modulators given in combination produced further increases in tumor growth delay with all of the cytotoxic therapies, and 5 of 12 of the animals treated with the 3-modulator combination and cyclophosphamide were long-term survivors. Although neither tetrahydrocortisol/-cyclodextrin tetradecasulfate, minocycline, nor the three modulator combination impacted the number of lung metastases, there was a decrease in the number of large lung metastases. Treatment with the cytotoxic therapies alone reduced the number of lung metastases. Addition of the modulators to treatment with the cytotoxic therapies resulted in a further reduction in the number of lung metastases. These results indicate that agents that inhibit the breakdown of the extracellular matrix can be useful additions to the treatment of solid tumors.Abbreviations 14(SO4)ßCD -cyclodextrin tetradecasulfate - THC tetrahydrocortisol - CDDP cis-diamminedichloroplatinum(II) - 4-HC 4-hydroperoxycyclophosphamide - BCNU N,N-bis(2-chloroethyl)-N-nitrosourea - CAM chick embryo chorioallantoic membrane; IC50, concentration of a drug required to kill 50% of the cells This work was supported by NIH grant P01-CA38493 and a grant from Bristol-Myers-Squibb, Inc., Wallingford, Connecticut  相似文献   
3.
Hypothesis: Analysis of salivary gland lesions by FNAC and correlation with histopathology. To evaluate utility of FNAC in salivary gland lesions.Back ground: Salivary gland lesions form about 2–6.5% of all head and neck neoplasms in adults. They are easily accessible for FNAC (Fine Needle Aspiration Cytology) and risks of fistula formation or tumour implantation are low compared surgical biopsy. Also, cytology can provide a distinction between asalivary and non salivary lesion, benign and malignant lesions so also specific and non specific inflammation. Methods: Seventy patients were studied prospectively over two years. FNAC was done using 10 cc syringes and 20–22 no. needle. Histomorphology was assessed on routine H & E (haemotxylin and eosin) stained paraffin sections. SPAS (periodic acid Schiff) and mucicarmine satins were also done. Results: 80% of the lesions were neoplastic (61% benign, 31% malignant) and 20% were neoplastic. Pleomorphic adenoma was the most frequent benign neoplasm while mucoepidermoid carcinoma was the most frequent malignant lesion. Among the non neoplastic lesions, the maximum number of cases were of chronic sialadentis. In the present study, FNAC has a sensitivity of 94.54% and specificity of 80.95% for neoplastic lesions. Conclusions: FNAC was found to be a useful diagnostic tool in the evaluation of salivary gland lesions because of its simplicity, excellent patient compliance and rapid diagnosis. This cost effective tool is invaluable in planning the surgical management of the patient.  相似文献   
4.
5.
Purpose: To survey the opinion of oculoplastic surgeons on the assessment and management of lower eyelid retraction (LLR).

Methods: A web-based survey queried oculoplastic surgeon members of Ojoplast, Spanish and Brazilian Oculoplastic Societies on the management of LLR. The frequency and percentage proportions of the responses were analyzed.

Results: One hundred ninety-six oculoplastic surgeons participated in the survey. The main cause of LLR is post-blepharoplasty (62;31.6%). The most used sign to detect LLR is scleral show. The most common approaches to managing LLR are lateral canthal surgery (164/593;27.6%), autogenous spacers (148/593; 24.9%) and retractor release (131/593;22.1%). The preferred autogenous graft material includes ear cartilage (102/260;39.2%). The majority of surgeons (161/314; 51.3%) recommend massage or steroids injection (80/314;25.5%) for early post-blepharoplasty LLR, while, 54.1% (106/196) of participants suggested waiting for at least six months prior to surgical intervention. Frost suture is used after most LLR surgeries (154/196;91.1%). Incomplete correction is the main complication (111/310;35.8%) of LLR surgery. For mild LLR, 48% of the responders prefer clinical treatment; conversely, severe cases routinely require combined surgical techniques.

Conclusions: Oculoplastic surgeons frequently diagnose LLR based on scleral show. LLR management depends on the cause and severity of lid retraction. Mild cases, in general, receive clinical treatment and severe cases need a combination of surgical techniques and grafts.  相似文献   

6.
7.
The cytotoxicity of the topoisomerase I inhibitors, camptothecin and topotecan, toward exponentially growing EMT-6 murine mammary carcinoma cells under various conditions of oxygenation, pH and temperature was assessed. Under normal pH (pH 7.40) conditions both camptothecin and topotecan were more cytotoxic toward normally oxygenated cells. Both agents were more cytotoxic under acidic pH (pH 6.45) and the differential in cytotoxicity due to the cellular oxygenation level disappeared. Neither camptothecin nor topotecan was enhanced in cytotoxicity by hyperthermia (42°C or 43°C, 60 min) during drug exposure. Both camptothecin and topotecan killed increasing numbers of FSaIIC tumor cells with increasing dose of the drugs in vivo in a log/linear manner. Local hyperthermia (43°C, 30 min) increased the tumor cell killing of the drugs but decreased the toxicity of these agents to the bone marrow granulocyte/macrophage-colony-forming units. Topotecan was a more effective modulator of cisplatin than was camptothecin, as determined by FSaIIC tumor cell survival assay and by FSaIIC tumor growth delay. Although both camptothecin and topotecan were effective additions to a treatment regimen including cisplatin and daily fractionated radiation (5×3Gy), neither of these topoisomerase I inhibitors increased the tumor growth delay produced by the trimodality regimen of cisplatin/hyperthermia/radiation.Abbreviations Cisplatin cis-diamminedichloroplatinum(II) - GM-CFU granulocyte-macrophage progenitor colony-forming unit This work was supported by NCI grants RO1-47379 and RO1-50174  相似文献   
8.
Understanding the underlying mechanisms of COVID-19 progression and the impact of various pharmaceutical interventions is crucial for the clinical management of the disease. We developed a comprehensive mathematical framework based on the known mechanisms of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, incorporating the renin−angiotensin system and ACE2, which the virus exploits for cellular entry, key elements of the innate and adaptive immune responses, the role of inflammatory cytokines, and the coagulation cascade for thrombus formation. The model predicts the evolution of viral load, immune cells, cytokines, thrombosis, and oxygen saturation based on patient baseline condition and the presence of comorbidities. Model predictions were validated with clinical data from healthy people and COVID-19 patients, and the results were used to gain insight into identified risk factors of disease progression including older age; comorbidities such as obesity, diabetes, and hypertension; and dysregulated immune response. We then simulated treatment with various drug classes to identify optimal therapeutic protocols. We found that the outcome of any treatment depends on the sustained response rate of activated CD8+ T cells and sufficient control of the innate immune response. Furthermore, the best treatment—or combination of treatments—depends on the preinfection health status of the patient. Our mathematical framework provides important insight into SARS-CoV-2 pathogenesis and could be used as the basis for personalized, optimal management of COVID-19.

COVID-19 has created unprecedented challenges for the health care system, and, until an effective vaccine is developed and made widely available, treatment options are limited. A challenge to the development of optimal treatment strategies is the extreme heterogeneity of presentation. Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) results in a syndrome that ranges in severity from asymptomatic to multiorgan failure and death. In addition to local complications in the lung, the virus can cause systemic inflammation and disseminated microthrombosis, which can cause stroke, myocardial infarction, or pulmonary emboli (14). Risk factors for poor COVID-19 outcome include advanced age, obesity, diabetes, and hypertension (513).Computational analyses can provide insights into the transmission, control, progression, and underlying mechanisms of infectious diseases. Indeed, epidemiological and statistical modeling has been used for COVID-19, providing powerful insights into comorbidities, transmission dynamics, and control of the disease (1417). However, to date, these analyses have been population dynamics models of SARS-CoV-2 infection and transmission or correlative analyses of COVID-19 comorbidities and treatment response. Simple viral dynamics models have been also developed and used to predict the SARS-CoV-2 response to antiviral drugs (18, 19). These models, however, do not explicitly consider the biological or physiological mechanisms underlying disease progression or the time course of response to various therapeutic interventions, and only a few more-sophisticated models have been developed toward this direction (20, 21).Several therapies targeting various aspects of COVID-19 pathogenesis have been proposed and have either completed—or are currently being tested in—clinical trials (22). Despite strong biologic rationale, these treatments have generally produced conflicting results in the clinic. For example, trials of antiviral therapies (e.g., remdesivir) have been mixed: The original trial from China failed (23), a subsequent trial in the United States led to approval of remdesivir in the United States and other countries (24), and the recent results of the World Health Organization Solidarity trial again show no benefit (25). Other antiviral drugs alone or in combination are also showing promise (26).Other potential treatments include antiinflammatory drugs and antithrombotic agents. Because of the systemic inflammation seen in many patients, antiinflammatory drugs have been tested, including anti-IL6/IL6R therapy (e.g., tocilizumab, siltuximab) and anti-JAK1/2 drugs (e.g., barcitinib). It is not clear whether these drugs will be effective as stand-alone treatments, particularly after the recent failure of tocilizumab in a phase III trial (1, 2729). In addition, given that a common complication of COVID-19 is the development of coagulopathies with microvascular thrombi potentially leading to the dysfunction of multiple organ systems (2, 3), antithrombotic drugs (e.g., low molecular weight heparin) are being tested. Recognizing the interactions of COVID-19 with the immune system (30), the corticosteroid dexamethasone has been tested, showing some promising results. Given the large range of patient comorbidities, disease severities, and variety of complications such as thrombosis, it is likely that patients will have heterogeneous responses to any given therapy, and such heterogeneity will continue to be a challenge for clinical trials of unselected COVID-19 patients (31).Here, we developed a systems biology-based mathematical model to address this urgent need. Our model incorporates the known mechanisms of SARS-CoV-2 pathogenesis and the potential mechanisms of action of various therapeutic interventions that have been tested in COVID-19 patients. In previous work, we have exploited angiotensin receptor blockers (ARBs) and angiotensin converting enzyme inhibitors (ACEis) for the improvement of cancer therapies and developed mathematical models of the renin−angiotensin system in the context of cancer desmoplasia (3235). Using a similar approach, we developed a detailed model that includes lung infection by the SARS-CoV-2 virus and a pharmacokinetic/pharmacodynamic (PK/PD) model of infection and thrombosis to simulate events that take place throughout the body during COVID-19 progression (Fig. 1 and SI Appendix, Fig. S1). The model is first validated against clinical data of healthy people and COVID-19 patients and then used to simulate disease progression in patients with specific comorbidities. Subsequently, we present model predictions for various therapies currently employed for treatment of COVID-19 alone or in combination, and we identify protocols for optimal clinical management for each of the clinically observed COVID-19 phenotypes.Open in a separate windowFig. 1.Schematic of the detailed lung model. The model incorporates the virus infection of epithelial and endothelial cells, the RAS, T cells activation and immune checkpoints, the known IL6 pathways, neutrophils, and macrophages, as well as the formation of NETs, and the coagulation cascade. The lung model is coupled with a PK/PD model for the virus and thrombi dissemination through the body.  相似文献   
9.
10.
Three patients with metastatic breast cancer responded to diethylstilbestrol (DES) therapy, but later they developed endometrial carcinoma. Evidence is presented to support the hypothesis that endometrial carcinoma can occur in breast cancer patients receiving diethylstilbestrol therapy.  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