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   14732篇
  免费   968篇
  国内免费   51篇
耳鼻咽喉   96篇
儿科学   512篇
妇产科学   471篇
基础医学   1870篇
口腔科学   218篇
临床医学   2098篇
内科学   2652篇
皮肤病学   276篇
神经病学   1585篇
特种医学   301篇
外科学   1300篇
综合类   122篇
现状与发展   1篇
一般理论   16篇
预防医学   2028篇
眼科学   335篇
药学   948篇
中国医学   15篇
肿瘤学   907篇
  2023年   93篇
  2022年   153篇
  2021年   348篇
  2020年   199篇
  2019年   363篇
  2018年   417篇
  2017年   273篇
  2016年   318篇
  2015年   388篇
  2014年   516篇
  2013年   791篇
  2012年   1103篇
  2011年   1172篇
  2010年   641篇
  2009年   521篇
  2008年   1037篇
  2007年   1045篇
  2006年   1047篇
  2005年   1019篇
  2004年   953篇
  2003年   907篇
  2002年   863篇
  2001年   97篇
  2000年   70篇
  1999年   101篇
  1998年   142篇
  1997年   134篇
  1996年   124篇
  1995年   121篇
  1994年   68篇
  1993年   91篇
  1992年   59篇
  1991年   54篇
  1990年   46篇
  1989年   40篇
  1988年   48篇
  1987年   31篇
  1986年   31篇
  1985年   31篇
  1984年   45篇
  1983年   38篇
  1982年   45篇
  1981年   44篇
  1980年   33篇
  1979年   13篇
  1978年   18篇
  1977年   9篇
  1976年   8篇
  1973年   6篇
  1972年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
172.
BACKGROUND: The current tumor-node-metastasis system is inadequate to accurately classify patients in terms of prognosis. Thus, with the availability of recently developed molecular tools, considerable interest lies in discovering prognostic markers in order to guide treatment decisions. In this study, we sought to determine the prognostic significance of the cell cycle regulator cyclin D1 in oropharyngeal squamous cell carcinoma (OSCC). EXPERIMENTAL DESIGN: We studied the protein expression levels of cyclin D1 on a tissue microarray composed of 63 OSCCs with long-term follow-up data available. Protein expression was analyzed with an automated in situ quantitative (AQUA) method which allows preservation of tissue morphology while quantifying protein expression in paraffin-embedded tissue. RESULTS: The mean follow-up time was 35 months. High cyclin D1 nuclear expression was associated with increased 5-year local recurrence rate (48% versus 15%), inferior 5-year disease-free survival (16% versus 58%), and inferior 5-year overall survival (17% versus 53%). In multivariate Cox regression, high nuclear cyclin D1 expression was an independent predictor for local recurrence, disease-free survival, and overall survival at 5 years. CONCLUSIONS: Our results indicate that quantitative assessment of nuclear cyclin D1 expression level by automated in situ quantitative analysis is a strong predictor for outcome in OSCC. Thus, cyclin D1 may be a potential target for molecular intervention in patients with oropharyngeal squamous cell cancer.  相似文献   
173.
PURPOSE: A randomized three-arm phase II study was undertaken to evaluate the optimum administration schedule of pemetrexed and gemcitabine in chemotherapy-na?ve patients with non-small-cell lung cancer. PATIENTS AND METHODS: Patients were randomly assigned to three schedules of pemetrexed 500 mg/m2 plus gemcitabine 1,250 mg/m2, separated by a 90-minute interval, on a 21-day cycle as follows: schedule A, pemetrexed followed by gemcitabine on day 1 and gemcitabine on day 8; schedule B, gemcitabine followed by pemetrexed on day 1 and gemcitabine on day 8; and schedule C, gemcitabine on day 1 and pemetrexed followed by gemcitabine on day 8. RESULTS: One hundred fifty-two eligible patients (schedule A, n = 59; schedule B, n = 31, and schedule C, n = 62) received a median of five (schedule A), two (schedule B), and four (schedule C) treatment cycles. Overall, 66% of patients experienced grade 3 or 4 neutropenia. Common grade 3 and 4 nonhematologic toxicities were dyspnea (11%), fatigue (16%), and transaminase elevation (9%). Schedule A seemed less toxic compared with schedule C (grade 3 or 4 events: 86% v 94%, respectively; P = .19; grade 4 events: 39% v 48%, respectively; P = .30). Schedule B was closed at interim analysis for inferior efficacy. Schedule A, with a confirmed response rate of 31% (95% CI, 20% to 45%), met the protocol-defined efficacy criteria, whereas schedule C, with a confirmed response rate of 16.1% (95% CI, 11% to 34%), did not. Median survival time and time to progression were 11.4 and 4.4 months, respectively, with no observable difference between the arms. CONCLUSION: Pemetrexed and gemcitabine administered as outlined for schedule A met the protocol-defined efficacy criteria, was less toxic compared with the other treatment schedules, and should be further evaluated.  相似文献   
174.
PURPOSE: To determine the incidence of second malignancies among patients with Hodgkin's lymphoma (HL) treated with autologous hematopoietic stem cell transplantation (AHSCT) compared with patients receiving conventional therapy alone and to identify potential risk factors for their occurrence. PATIENTS AND METHODS: We analyzed data on 1,732 consecutive patients with HL treated at the British Columbia Cancer Agency from 1976 to 2001, including 202 patients undergoing AHSCT. The median follow-up duration was 9.8 years for the whole cohort, 9.7 years for those patients treated with conventional therapy, and 7.8 years from AHSCT. RESULTS: The cumulative incidence of developing any second malignancy 15 years after therapy for HL was 9% (risk ratio = 3.5; P < .001); however, the incidence did not differ between those patients receiving conventional therapy alone compared with those undergoing AHSCT (10% and 8%, respectively; P = .48). In multivariate analysis, the only factor significantly associated with an increased risk of developing any second neoplasm or solid tumor was age > or = 35 years (P < .0001). An increased risk of therapy-induced acute myeloid leukemia and therapy-induced myelodysplastic syndrome was seen for patients aged > or = 35 years (P = .03) and stage III/IV (P = .04). CONCLUSION: Patients with HL are at increased risk of developing a second neoplasm. However, those patients undergoing AHSCT do not seem to be at greater risk compared with those patients receiving conventional therapy alone, at least during the first decade after therapy.  相似文献   
175.
It has been previously suggested that morphine can regulate the expression and function of some proteins of the cytoskeleton. In the present study, we used real-time quantitative polymerase chain reaction to examine the effects of chronic morphine administration, in rat striatum, on 14 proteins involved in microtubule polymerization and stabilization, intracellular trafficking, and serving as markers of neuronal growth and degeneration. Chronic morphine treatment led to modulation of the mRNA level of seven of the 14 genes tested. Glial fibrillary acidic protein (Gfap) and activity-regulated cytoskeleton-associated protein (Arc) mRNA were upregulated, while growth associated protein (Gap43), clathrin heavy chain (Cltc), alpha-tubulin, Tau, and stathmin were downregulated. In order to determine if the regulation of an mRNA correlates with a modulation of the expression of the corresponding protein, immunoblot analyses were performed. With the exception of Gap43, the levels of Cltc, Gfap, Tau, stathmin, and alpha-tubulin proteins were found to be in good agreement with those from mRNA quantification. These results demonstrate that neuroadaptation to chronic morphine administration in rat striatum implies modifications of the expression pattern of several genes and proteins of the cytoskeleton and cytoskeleton-associated components.  相似文献   
176.
177.
178.
179.
180.
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