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   923篇
  免费   62篇
  国内免费   2篇
耳鼻咽喉   2篇
儿科学   52篇
妇产科学   110篇
基础医学   91篇
口腔科学   25篇
临床医学   69篇
内科学   136篇
皮肤病学   8篇
神经病学   19篇
特种医学   77篇
外科学   134篇
综合类   15篇
一般理论   1篇
预防医学   29篇
眼科学   99篇
药学   50篇
肿瘤学   70篇
  2023年   4篇
  2022年   7篇
  2021年   23篇
  2020年   8篇
  2019年   19篇
  2018年   13篇
  2017年   14篇
  2016年   18篇
  2015年   31篇
  2014年   35篇
  2013年   32篇
  2012年   34篇
  2011年   37篇
  2010年   30篇
  2009年   35篇
  2008年   31篇
  2007年   23篇
  2006年   23篇
  2005年   25篇
  2004年   14篇
  2003年   23篇
  2002年   15篇
  2001年   31篇
  2000年   15篇
  1999年   15篇
  1998年   25篇
  1997年   31篇
  1996年   27篇
  1995年   17篇
  1994年   27篇
  1993年   16篇
  1992年   30篇
  1991年   25篇
  1990年   15篇
  1989年   32篇
  1988年   28篇
  1987年   18篇
  1986年   28篇
  1985年   22篇
  1984年   20篇
  1983年   16篇
  1982年   7篇
  1981年   4篇
  1980年   7篇
  1976年   8篇
  1975年   3篇
  1974年   3篇
  1973年   4篇
  1967年   3篇
  1965年   2篇
排序方式: 共有987条查询结果,搜索用时 78 毫秒
151.
152.
Abstract: Aim: The aim was to compare the working profiles of Finnish and Norwegian dental hygienists in public and private practice. To this end, we compared the procedures performed, the type of patients and the time devoted to different tasks. Subjects and methods: A questionnaire survey was originally conducted among a representative sample of dental hygienists in Finland (n = 595) and all authorized dental hygienists in Norway (n = 1 138) in 2004. The questionnaires collected data on the dental hygienists’ age, gender, year of graduation, working experience, work sector (private or public), working time spent on different activities and patient groups. The questionnaire also assessed how frequently the dental hygienists performed 25 different treatment measures. Results: The Norwegian dental hygienists spent 45.4% of their clinical time on check‐ups, whereas the Finns spent 49.9% of their time scaling. Dental hygienists in Finland and Norway working in the public sector spent 42.9% and 74.6% of their working time dealing with children and youth respectively. Conclusions: The working profiles of dental hygienists in Finland and Norway were quite similar, although differences in distribution by activities, type of patients and treatment measures do exist. The main activity of the dental hygienists was clinical work. The most commonly practised clinical activity among Finnish dental hygienists was scaling, and among Norwegians, check‐ups. Public dental hygienists in both countries dealt mainly with children and youths. Oral hygiene instruction was the most commonly reported treatment measure among both Finns and Norwegians.  相似文献   
153.
154.

BACKGROUND:

The objective of this study was to determine whether specific single nucleotide polymorphisms (SNPs) from nucleotide excision repair (NER) and homologous recombination (HR) DNA repair pathways are associated with sensitivity to trabectedin in patients with soft tissue sarcoma (STS).

METHODS:

The authors analyzed excision repair cross‐complementation group 5/xeroderma pigmentosum group G (ERCC5/XPG) (NER), excision repair cross‐complementation group 1 (ERCC1) (NER), and breast cancer 1 (BRCA1) (HR) SNPs and messenger RNA expression levels in tumor specimens from 113 patients with advanced STS who were enrolled in previously published phase 2 trials or in a compassionate‐use program. The 6‐month progression‐free rate (PFR), progression‐free survival (PFS), and overall survival (OS) were analyzed according to ERCC5, ERCC1, and BRCA1 status using log‐rank tests.

RESULTS:

High expression of the common allele (aspartic acid at codon 1104) of ERCC5, high expression of ERCC1, and BRCA1 haplotype were associated significantly with improved PFR, PFS, and OS. The ERCC1 thymine‐to‐cytosine (T→C) SNP at codon 19007 and BRCA1 expression were not associated with outcome. On univariate analysis, tumor histology, favorable NER status (high expression of common ERCC5 and/or high ERCC1 expression status), and favorable BRCA1 haplotype (at least 1 triple‐adenine plus guanine [AAAG] allele) were the sole variables associated significantly with PFS and OS.

CONCLUSIONS:

In the current study, ERCC5, ERCC1, and BRCA1 status represented a potential DNA repair signature that could be used for the prediction of clinical response to trabectedin in patients with STS. Cancer 2011. © 2011 American Cancer Society.  相似文献   
155.
156.
Summary. Background: Osteoprotegerin (OPG) concentration in serum is associated with the presence and severity of atherosclerosis. Objective: To investigate the association between serum osteoprotegerin and the risk of a future myocardial infarction, ischemic stroke and mortality in a general population. Patients/methods: OPG was measured in serum collected from 6265 subjects recruited from a general population without a prior myocardial infarction and ischemic stroke (the Tromsø Study). Incident myocardial infarction, ischemic stroke and mortality were registered during follow‐up. Cox regression models were used to estimate crude and adjusted hazard ratios and 95% confidence intervals (HR; 95% CI). Results: There were 575 myocardial infarctions, 284 ischemic strokes and 824 deaths (146 deaths as a result of ischemic heart disease, 78 deaths because of stroke and 600 deaths due to other causes) in the cohort during a median of 10.6 years of follow‐up. Serum OPG (per SD [1.13 ng mL?1] increase in OPG) was associated with an increased risk of a myocardial infarction (1.20; 1.11–1.31), ischemic stroke (1.32; 1.18–1.47), total mortality (1.34; 1.26–1.42), death because of ischemic heart disease, (1.35; 1.18–1.54), stroke (1.44; 1.19–1.75) and non‐vascular causes (1.31; 1.22–1.41) after adjustment for age, gender, current smoking, systolic blood pressure, body mass index, high density lipoprotein cholesterol, total cholesterol, creatinine, high sensitivity C‐reactive protein (CRP) and diabetes mellitus or HbA1c > 6.1%. No association was detected between OPG and incident hemorrhagic stroke (1.02; 0.73–1.43). Conclusions: Serum OPG was associated with future risk of myocardial infarction, ischemic stroke, total mortality, mortality of ischemic heart disease, stroke and of non‐vascular causes independent of traditional cardiovascular risk factors.  相似文献   
157.
158.
Most undifferentiated thyroid carcinomas express p53 mutants and thereafter, are very resistant to chemotherapy. p53 reactivation and induction of massive apoptosis (Prima-1) is a compound restoring the tumor-suppressor activity of p53 mutants. We tested the effect of Prima-1 in thyroid cancer cells harboring p53 mutations. Increasing doses of Prima-1 reduced viability of thyroid cancer cells at a variable extent (range 20-80%). Prima-1 up-regulated p53 target genes (p21(WAF1) , BCL2-associated X protein (Bax), and murine double minute 2 (MDM2)), in BC-PAP and Hth-74 cells (expressing D259Y/K286E and K286E p53 mutants) but had no effect in SW1736 (p53 null) and TPC-1 (expressing wild-type p53) thyroid cancer cells. Prima-1 also increased the cytotoxic effects of either doxorubicin or cisplatin in thyroid cancer cells, including the chemo-resistant 8305C, Hth-74 and BC-PAP cells. Moreover, real-time PCR and Western blot indicated that Prima-1 increases the mRNA of thyroid-specific differentiation markers in thyroid cancer cells. Fluorescence-activated cell sorting analysis revealed that Prima-1 effect on thyroid cancer cells occurs via the enhancement of both cell cycle arrest and apoptosis. Small interfering RNA experiments indicated that Prima-1 effect is mediated by p53 mutants but not by the p53 paralog p73. Moreover, in C-643 thyroid cancer cells, forced to ectopically express wild-type p53, Prima-1 prevented the dominant negative effect of double K248Q/K286E p53 mutant. Finally, co-IP experiments indicated that in Hth-74 cells Prima-1 prevents the ability of p53 mutants to sequestrate the p53 paralog TAp73. These in vitro studies imply that p53 mutant reactivation by small compounds may become a novel anticancer therapy in undifferentiated thyroid carcinomas.  相似文献   
159.
A recent prospective clinical trial provides further evidence that breast cancers arising in germline BRCA1 mutation carriers are highly sensitive to cisplatin chemotherapy. The potential significance of these data for the management of patients with BRCA1-related and BRCA2-related breast cancer is discussed.In a previous issue of Breast Cancer Research Tomasz Byrski and colleagues present the results of a prospective phase II study of cisplatin in BRCA1-related metastatic breast cancer - that is, breast cancer arising in women with a germline mutation in BRCA1 [1]. They report evidence of substantial efficacy with an overall response rate of 80%, including 45% with complete response, and a time to progression of 12 months. The majority of patients in the study had triple receptor-negative breast cancer, and this time to progression compares favorably with median progression-free survival for triple receptor-negative breast cancer in contemporary series [2]. This study follows on from a retrospective study by the same group that reported a pathological complete response rate of 83% with neoadjuvant cisplatin chemotherapy, compared with a rate of 15% with nonrandomized comparator neoadjuvant chemotherapy [3].The molecular basis for these high response rates is well understood. Both BRCA1 and BRCA2 are required for DNA double-strand break repair by homologous recombination (HR-based DNA repair) [4,5]. Mutations in BRCA1 and BRCA2 inactivate protein function, and in cancer the wild-type allele is almost invariably lost, leading to a defect in HR-based DNA repair in the cancer. Platinum chemotherapy generates interstrand cross-links that can only be adequately repaired by HR-based DNA repair, and consequently BRCA1-deficient and BRCA2-deficient cells are highly sensitive to platinum chemotherapy both in vitro and in vivo. With high response rates in a prospective clinical trial, and a strong biological rationale, it is time to ask whether we are moving towards a new chemotherapy standard for BRCA1-related, and potentially by inference BRCA2-related, breast cancer or whether we need more evidence.The main strength of the current study is that it has been carried out at all. BRCA1 mutations account for a small proportion of patients with advanced breast cancer, even in countries with founder mutations, and this presents a substantial barrier to running studies testing standard chemotherapy. Use of the chemotherapy regimen outside the trial, and the wide availability of novel therapy trials competing for the same patients, add to the challenges of recruiting such trials. Nevertheless, the study by Byrski and colleagues is an open-label single-arm study of only 20 patients, with no central radiological confirmation of response rates, and both this study design and this size make a meaningful interpretation of progression-free survival very difficult. The study was in addition not prospectively registered in a clinical trial registry, removing one of the safeguards against publication bias.The study is dominated by women with three specific mutations in BRCA1 that represent the three founder mutations found in the Polish population [1], with over one-half being the single mutation 5382insC. One of these mutations, C61G, is predicted not to sensitize to cisplatin on the basis of preclinical data [6] yet cancers with this mutation appear to be just as sensitive to cisplatin in the study [1], a discrepancy for which it is important to understand the basis. Prior studies reported by this group have also been drawn from the Polish founder mutations, and we have limited data on the response of cancers with other BRCA1 mutations, and very limited data for BRCA2 mutations.Although the data for BRCA1/2-related breast are therefore relatively limited, there are substantial data on the sensitivity of BRCA1-related and BRCA2-related ovarian cancers to platinum-based chemotherapy [7,8]. BRCA1/2-related serous ovarian cancers are highly sensitive to platinum chemotherapy, and remain sensitive to repeat challenges with platinum chemotherapy, which likely explains the improved survival of BRCA1/2-related serous ovarian cancer compared with BRCA1/2 wild-type serous ovarian cancer [8].Should the accumulation of data, which includes this study by Byrski and colleagues, alter our approach to the treatment of BRCA1-related and BRCA2-related breast cancer? For patients with metastatic BRCA1-related breast cancer, although the data are limited, it seems clear that these patients should be offered the option of platinum-containing chemotherapy at some point during their treatment course. Whether platinum chemotherapy should be used as the first line in preference to other chemotherapy agents is unclear, and this is the subject of the BRCA trial (NCT00321633, NCT00532727) that randomizes first-line patients between carboplatin and docetaxel. For those with BRCA1 mutation-associated triple receptor-negative breast cancer and anthracycline-resistant and taxane-resistant disease, where there are few available active therapies, and the option of platinum-agent chemotherapy seems well founded.Whether the platinum agent should be cisplatin or whether carboplatin would have a similar response rate is unknown. Any difference in efficacy between the two drugs is likely to be small and may be outweighed by logistical and toxicity advantages for the patient. Whether patients with evidence of disease response and a long platinum-free interval (>6 months off chemotherapy) should be retreated with platinum-based chemotherapy on progression or whether they should be treated with alternative chemotherapy regimens remains unclear, and we await data to guide such decisions. Although there are few direct data on BRCA2-related breast cancer, the strength of the biological rational, the comparative data between BRCA1 and BRCA2 in ovarian cancer, and the evidence of poly(ADP ribose) polymerase (PARP) inhibitor efficacy in BRCA2-related breast cancer [9] all suggest that similar advice should apply to BRCA2-related breast cancer.What about the curative setting and patients receiving adjuvant or neoadjuvant chemotherapy? Here the data are less robust. Standard adjuvant anthracycline/taxane chemotherapy cures a substantial proportion of women with breast cancer, with evidence of better outcomes and therapy responses in the BRCA1/2 carrier population [10,11], so changes to this standard should only be made on the basis of strong evidence. At present the data to support platinum agents in this context are limited to retrospective analysis [3] or to prospective data for a very small number of patients [12]. Prospective studies are still required before routine practice changes in the curative setting. The one current exception to this is in the treatment of HER2-positive breast cancer in BRCA1/2 carriers. Relative equipoise has already been shown in the general breast cancer population for the TCH (docetaxel, carboplatin, trastuzumab) regimen compared with standard anthracycline-taxane-trastuzumab-based chemotherapy [13], and the TCH (docetaxel, carboplatin, trastuzumab) regimen presents an attractive option for BRCA1/2 carriers with HER2-positive breast cancer.PARP inhibitors target the same HR-based DNA repair defect as cisplatin chemotherapy, and there is evidence of efficacy for the PARP inhibitor olaparib in BRCA1-related and BRCA2-related breast cancer with substantial prior chemotherapy exposure [9]. PARP inhibitors target the DNA repair defect in a more specific fashion and are well tolerated without typical chemotherapy side effects [9]. The challenge in BRCA1/2-related advanced breast cancer is to develop and support a collaborative mechanism where patients can be identified and entered into randomized trials that test novel therapies such as PARP inhibitors, or mechanistically based chemotherapy, to robustly assess the efficacy relative to standard care, and therefore allow these patients to benefit from these BRCA1/2-focused treatments.  相似文献   
160.
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