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   5762篇
  免费   283篇
  国内免费   13篇
耳鼻咽喉   48篇
儿科学   221篇
妇产科学   99篇
基础医学   649篇
口腔科学   149篇
临床医学   463篇
内科学   998篇
皮肤病学   83篇
神经病学   407篇
特种医学   200篇
外科学   682篇
综合类   74篇
一般理论   5篇
预防医学   274篇
眼科学   223篇
药学   683篇
  1篇
中国医学   77篇
肿瘤学   722篇
  2024年   5篇
  2023年   34篇
  2022年   116篇
  2021年   200篇
  2020年   99篇
  2019年   134篇
  2018年   174篇
  2017年   112篇
  2016年   148篇
  2015年   199篇
  2014年   228篇
  2013年   331篇
  2012年   503篇
  2011年   474篇
  2010年   257篇
  2009年   255篇
  2008年   362篇
  2007年   367篇
  2006年   346篇
  2005年   352篇
  2004年   307篇
  2003年   266篇
  2002年   214篇
  2001年   57篇
  2000年   59篇
  1999年   54篇
  1998年   47篇
  1997年   23篇
  1996年   33篇
  1995年   35篇
  1994年   27篇
  1993年   30篇
  1992年   29篇
  1991年   27篇
  1990年   13篇
  1989年   15篇
  1988年   9篇
  1987年   6篇
  1986年   5篇
  1985年   10篇
  1984年   13篇
  1983年   8篇
  1982年   10篇
  1981年   10篇
  1980年   11篇
  1979年   6篇
  1976年   4篇
  1973年   3篇
  1972年   3篇
  1971年   5篇
排序方式: 共有6058条查询结果,搜索用时 15 毫秒
51.
The p21-activated kinases signal through a number of cellular pathways fundamental to growth, differentiation and apoptosis. A wealth of information has accumulated at an impressive pace in the recent past, both with regard to previously identified targets for p21-activated kinases that regulate the actin cytoskeleton and cellular stress pathways and with regard to newly identified targets and their role in cancer. Emerging data also provide new clues towards a previously unappreciated link between these various cellular processes. The present review attempts to provide a quick tutorial to the reader about the evolving significance of p21-activated kinases and small GTPases in breast cancer, using information from mouse models, tissue culture studies, and human materials.  相似文献   
52.
 Tirapazamine (3-amino-1,2,4-benzotriazine-1,4-di-N-oxide; SR 259075) is a selective hypoxic cell cytotoxic agent that is bioreductively activated in tumours to a reactive-drug free radical. Preclinically the agent has been shown to possess additive and synergistic anti-tumour activity in combination with radiotherapy and chemotherapy regimens. In the present study the pharmacokinetics and metabolism of tirapazamine were investigated in mice and patients as part of pre-clinical and phase I investigations. The objectives of this work were twofold; firstly, to evaluate retrospectively the utility of a pharmacokinetically guided dose-escalation (PGDE) strategy for tirapazamine, and secondly, to investigate if pharmacologically relevant plasma concentrations could be achieved at tolerable doses. Pharmacokinetic studies for PGDE were conducted in mice at four dose levels ranging from one-tenth of the LD10 to the LD50. The AUC at the LD10 (2932 μg ml-1min) was used to determine a target AUC value of 1173 μg ml-1min (equivalent to 40% of the mouse LD10 AUC) for clinical studies. A phase I study to investigate the tolerance of a single i.v. infusion of tirapazamine (once every 3 weeks) was initiated with close pharmacokinetic monitoring. The starting dose (36 mg/m2) was based on toxicity data obtained in the mouse, rat and dog. Doses were escalated by increases in the volume and duration of infusion. A retrospective analysis of the pharmacokinetic and toxicity data was then made to determine the utility of a PGDE approach. The drug exhibited a steep dose-lethality relationship in mice (LD10 294 mg/m2, LD50 303 mg/m2). The major gross toxicities were body-weight loss (15–20%), pilo-erection and hypoactivity at all dose levels. Sporadic ptosis and conjunctivitis were observed at doses of >300 mg/m2. The plasma elimination of tirapazamine fitted a monoexponential open model, with rapid elimination from the plasma (t 1/2=36±0.65 min) occuring at the LD10 dose of 294 mg/m2. A 10.3-fold increase in dose resulted in a 25.0-fold increase in AUC. Clinically, doses were escalated over the range of 36–450 mg/m2. Ototoxicity (tinnitus and reversible hearing loss) was dose-limiting at 450 mg/m2 and the MTD was 390 mg/m2 for this schedule. Pharmacokinetic analyses in patients revealed that the elimination of tirapazamine in patients was generally bi-phasic, with low inter-patient variability being found in clearance. A 12.5-fold increase in dose resulted in a 19.0-fold increase in AUC. There was good quantitative agreement in metabolite formation between mice and humans with respect to the two- and four-electron bioreductive metabolites. AUC values recorded for tirapazamine at the MTD of 390 mg/m2 (range 1035–1611 μg ml-1min) were similar to the target AUC in mice. Importantly, these levels are consistent with the levels required for radiation-dose enhancement and effective combination with cisplatin in mice. Given (a) the similarities in plasma pharmacokinetics and metabolism observed at the target AUC/MTD in mice, rats, dogs and humans, (b) the similar degree of plasma protein binding seen between species and (c) the relatively low inter-patient variability noted in drug clearance, a successful PGDE approach should have been feasible. The results also indicate that potentially therapeutic levels of tirapazamine are achievable in patients at tolerable doses. Received: 27 May 1996 / Accepted: 30 September 1996  相似文献   
53.
Primary Ewing’s sarcoma of the nasal bone has not been previously described. This case presented as a mass in the left ala of the nose in a five year old female child. The clinical, radiological, microscopic features are described and a review of literature is presented. The case was treated with neoadjuvant chemotherapy and local electron beam radiation therapy. The child was free of disease when she reported for follow up in July 1997. Although wide excision is part of the treatment approach in Ewing’s sarcoma, in sites where surgery is not suitable local radiotherapy and chemotherapy adequately controls primary disease.  相似文献   
54.
Primary Ewing’s sarcoma of the nasal bone has not been previously described. This case presented as a mass in the left ala of the nose in a five year old female child. The clinical, radiological, microscopic features are described and a review of literature is presented. The case was treated with neoadjuvant chemotherapy and local electron beam radiation therapy. The child was free of disease when she reported for follow up in July 1997. Although wide excision is part of the treatment approach in Ewing’s sarcoma, in sites where surgery is not suitable local radiotherapy and chemotherapy adequately controls primary disease.  相似文献   
55.
56.
Conclusion  Patients with stage I and II tumors had the best results with radical radiotherapy alone 5 years survival for patients with stage I and stage II tumors was 90-95% and 75-85% respectively Patients with advanced stage III & IV disease were treated Unoperable stage IV cancer patients had poor outcome and received only palliative treatment  相似文献   
57.
58.
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   
59.
Carcinoma of larynx is a common disease in North Indian population. It is seen commonly in smokers and alcoholics. It poses a serious health problem due to its tendency to cause airway obstruction and to make the patient aphonic if total larynxgectomy is done for curing this cancer. We conducted a retrospective analysis in 690 cases of carcinoma larynx presenting to Nehru Hospital, Postgraduate Institute of Medical Education and Research, Chandigarh. Various aspects of this disease like predisposing factors, patterns of spread, histological types, various treatment modalities, their complications and response of this disease to these therapeutic options were studied in detail.  相似文献   
60.
Survival rates of patients with either early and advanced stage non–small-cell lung cancer (NSCLC) have improved with newer systemic therapy and radiation techniques, including combination regimens, targeted therapies, and immunotherapies. The cancer cooperative groups have historically played a critical role in the advancement of NSCLC therapy. Annually, representatives from cooperative groups worldwide convene at the International Lung Cancer Congress (ILCC). In summer 2015, the ILCC reached its 16th anniversary. This article highlights the NSCLC studies presented by participating groups in 2015.  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