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Following adoption of moderately hypofractionated radiotherapy as a standard for localised prostate cancer, ultrahypofractioned radiotherapy delivered in five to seven fractions is rapidly being embraced by clinical practice and international guidelines. However, the question remains: how low can we go? Can radiotherapy for prostate cancer be delivered in fewer than five fractions? The current review summarises the evidence that radiotherapy for localised prostate cancer can be safely and effectively delivered in fewer than five fractions using high dose rate brachytherapy or stereotactic body radiotherapy. We also discuss important lessons learned from the single-fraction high dose rate brachytherapy experience.  相似文献   
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目的对近距离治疗计划的剂量参数在Oncentra治疗计划系统与MIM系统间产生的差异进行分析和研究。方法选取本院的43例妇科肿瘤患者近距离治疗计划,按照临床要求所有病例的靶区D90达到处方剂量。评估参数包括:靶区体积和D90,处方剂量总体积,靶区内的处方剂量体积以及危及器官包括:直肠,膀胱,小肠的D0.01cc,D1cc,D2cc。结果计划系统中的靶区体积和处方剂量值均明显小于MIM系统中相应的值(P<0.05),两系统显示出的处方体积相差不大。MIM系统中的靶区D90(676.74±54.82)cGy小于处方剂量,危及器官的受量则正好相反,即计划系统比MIM系统中相应的参数要小,其中直肠和膀胱的D0.01cc,D1cc,D2c,小肠的D0.01cc,D2cc的在两系统显示的值的差异均有统计学意义(P<0.05)。结论不同系统间传输相同的剂量和轮廓文件,DVH参数存在一定的差异,其主要原因是在不同系统对已勾画的各种器官轮廓计算体积存在算法上的不同。基于此,建议近距离计划在CT扫描时,尽量小的层厚可以消除或减少这种差异。  相似文献   
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PurposeTo understand the reasons behind current low utilization of brachytherapy for locally advanced cervical cancer in the United States.Methods and MaterialsA 17-item survey was e-mailed to the American Brachytherapy Society (ABS) listserv of active members in 2018. Responses of attending physicians in the United States were included in the analysis.ResultsAmong a total of 135 respondents, 81 completed the survey. Eighty-four percent agree/strongly agree that cervical brachytherapy is underutilized, and 46.9% disagree/strongly disagree that residents are receiving adequate training for brachytherapy; 75.3% agree/strongly agree that inadequate maintenance of brachytherapy skills is a major obstacle to brachytherapy use; and 71.6% agree/strongly agree that increased time requirement constitutes a major obstacle. Over 97% will recommend brachytherapy for most patients with cervical cancer if given access/time; 72.8% always perform their own brachytherapy, whereas 29.6% reported some type of barrier exists in performing brachytherapy themselves, with time required to perform brachytherapy (9.9%) being a leading factor. A quarter (24.7%) routinely refer to other radiation oncologists for brachytherapy. Even among ABS members, 37.0% reported that they would perform an intensity-modulated radiation therapy or stereotactic body radiation therapy boost in specific scenarios in potentially curable patients. The most common scenario is inability to place a uterine tandem (56.7%).ConclusionsThe underutilization of brachytherapy in cervical cancer is widely recognized by ABS members with inadequate training during residency and inadequate maintenance of skills being possible major contributing factors. Even among ABS members, there are identifiable barriers. Continued advocacy and future initiatives in enhancing access to brachytherapy training and efficiency are needed.  相似文献   
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PurposeThe purpose of this study was to evaluate the incidence of late severe (≥Grade 3) urinary toxicity and the long-term efficacy after low-dose-rate brachytherapy (LDR-BT) in patients with localized prostate cancer (PCa).Methods and MaterialsDuring the years 1999–2008, 241 patients with PCa who underwent LDR-BT with I125 and were followed up in Kuopio University Hospital were included to this analysis. The incidence of late severe (Grade 3) urinary toxicity and the long-term efficacy results were analyzed.ResultsAll D'Amico risk groups were represented, as 58.9%, 35.3%, and 5.8% of the patients were classified as low-, intermediate-, and high-risk patients, respectively. With a median followup of 11.4 years after implantation, the incidence of severe urinary toxicity increased throughout the followup period. The risk of Grade 3 urinary toxicity was highest among patients with higher Gleason scores (p = 0.016) and higher initial urine residual volumes (p = 0.017) and the cumulative incidence of severe urinary toxicity was 10.0%. The crude rate for transurethral prostatic resection was 5.8%. The relapse-free survival, the cause-specific survival, and the overall survival were 79.3%, 95.0%, and 66.4%, respectively.ConclusionsThe treatment was well tolerated as 90% of patients avoided any Grade 3 urinary toxicity. LDR-BT for localized PCa achieved high and durable efficacy. These results support the role of LDR-BT monotherapy as one of the valid primary treatment options for low-risk and favorable intermediate-risk patients.  相似文献   
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目的:量化分析后装治疗中,使用不同累积剂量计算方法导致的总剂量评估差异。方法:使用混合形变配准算法,对32例已完成后装插植治疗的宫颈癌患者共计进行108次形变配准,并计算每个患者的形变总剂量。根据膀胱和直肠的体积控制情况将32例患者分为体积控制组(18例)和体积未控制组(14例),计算比较组间累积剂量体积参数(D0.1 cc、D1 cc、D2 cc)和相似度系数(DSC),并与GEC-ESTRO推荐的分次间剂量累加方法相比较。结果:DSC随形变图像相对体积比值的增大而变差。体积控制组中,GEC-ESTRO推荐方法和形变累积剂量差异(DDIR/DGEC)较小。对于膀胱,体积控制组D2 cc的DDIR/DGEC最大值为1.05,低于未控组1.07;DDIR/DGEC最小值为0.91,高于未控组0.80。提示在使用形变剂量评估过程中,形变剂量值可能比GEC-ESTRO推荐的剂量计算方法偏高5%~7%或偏低9%~20%,偏高和偏低的原因主要为参与形变的体积差异导致剂量网格缩放。而D0.1 cc、D1 cc的DDIR/DGEC更接近1。对于直肠,控制组没有观察到DDIR/DGEC偏高的情况,D2 cc的DDIR/DGEC最大值为0.99,低于未控组1.06;最小值为0.80,低于未控组0.85,但未控制组平均偏高6%。而直肠的D0.1 cc、D1 cc、D2 cc的累积剂量比值都较接近,并且差异不如膀胱显著。结论:在后装治疗中,形变体积可以影响到形变累积剂量的计算结果,合理控制形变轮廓的体积不仅有助于提高形变的准确性,而且形变总剂量评估结果更稳定,建议在后装治疗过程中重视对膀胱和直肠的体积控制。  相似文献   
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BackgroundTo quantify rates and risk factors for toxicity after hepatic radioembolization using resin yttrium-90 microspheres.MethodsRadiation-Emitting SIR-Spheres in Non-resectable liver tumor (RESIN) registry enrollees were reviewed with 614 patients included. Mean patient age was 63.1±12.5 years. The majority of patients were male (n=375, 61%) and white (n=490, 80%). Common tumor types were hepatocellular (n=197, 32%), colorectal (n=187, 30%) and neuroendocrine (n=56, 9%). Hepatotoxicity was measured using the Common Terminology Criteria for Adverse Events (CTCAE v 5). Potential risk factors for hepatotoxicity were tested using the Kruskal-Wallis or Pearson Chi-squared tests, and multivariate linear regressions.ResultsAt 6 months, 115 patients (18.7%) died (n=91, 14.8%), entered hospice (n=20, 3.3%) or sought treatment elsewhere (n=4, 4%). Seven (1.1%) deaths were from liver decompensation. Grade 3 toxicity rates were: bilirubin (n=85, 13.8%), albumin (n=28, 4.6%), ALT (n=26, 4.2%) and AST (n=37, 6.0%). For each of these liver function test components, baseline abnormal labs predicted Grade 3 toxicity at follow-up by Kruskal-Wallis test (P<0.001) and linear regression (all P<0.03). Other significant factors predicting toxicity at regression included elevated Body-Mass Index (albumin P=0.0056), whole liver treatment (bilirubin P=0.046), and lower tumor volume (ALT and INR, P<0.035 for both).ConclusionsBaseline liver function abnormalities prior to radioembolization is the strongest predictor of post-treatment Grade 3 toxicity with rates as high as 13.8%. Toxicity rates for specific lab values are affected by large volume treatments especially with low tumor volumes.  相似文献   
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PurposeThe purpose of this study was to identify the time to achieve a prostate-specific antigen (PSA) nadir of ≤0.2 ng/mL and the related factors to achieve this goal.Materials and MethodsWe retrospectively reviewed 2218 Japanese prostate cancer patients who received 125I brachytherapy with or without external beam radiotherapy between 2003 and 2013 at one institution. Among them, patients followed up for ≥72 months and without luteinizing hormone–releasing hormone (LH-RH) agonist/antagonist were included (total of 1089 patients). The time to a PSA nadir of ≤0.2 ng/mL (months) was defined as the time between the date of implantation and the first time the lowest PSA value reached ≤0.2 ng/mL. Biochemical recurrence (BCR) was determined using the Phoenix definition. Multivariate linear regression analysis was performed to detect the related factors to achieve this nadir.ResultsWe assigned 409, 592, and 88 patients to the low-, intermediate-risk, and high-risk groups, respectively. The median followup time was 9.5 years. The median time to achieve a PSA nadir of ≤0.2 ng/mL was 44.0 (95% confidence interval: 42.3–45.7) months. The percentage of patients that achieved the nadir was 89.1%. BCR was noted in 107 (9.8%) patients. In the multivariate analysis of patients without BCR, younger age, larger prostate volume at implantation, higher initial PSA level, and monotherapy were significantly associated with longer time to achieve the PSA nadir.ConclusionThe median time to achieve a PSA nadir of ≤0.2 ng/mL was 44.0 months. Some patients, however, may require a lengthy period of time to do so.  相似文献   
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PurposeThe study is an audit of reporting dose and volume specifications as per the ICRU 58 for MUPIT-based interstitial brachytherapy in gynecological cancers. Correlation between total reference air kerma (TRAK) and isodose surface was also evaluated to understand the intensity of treatment in interstitial brachytherapy.Methods and MaterialsForty-two patients underwent HDR MUPIT-based interstitial brachytherapy 20 Gy in five fractions after EBRT during 2017–2019. Treated volume, high and low-dose regions, mean central dose, Dose Homogeneity Index (DHI), organ at risk doses, and TRAK values were computed.ResultsHigh-dose regions V150 mean was 12.4 cc and V200 was 4.58 cc; and low-dose region was 75.92 cc. The mean treated volume was 59.8 cc. The mean central dose was 3.7 Gy. DHI was 79%. The mean D2cm3 bladder and rectum were 2.9 Gy and 2.8 Gy. The mean TRAK was 0.16 cGy per fraction per hour at 1 m. TRAK values showed significant correlation with various isodose volumes (TRAK and V100: r = 0.943 p < 0.0005; and TRAK and V50: r = 0.953; p < 0.0005). A positive correlation was observed between TRAK and the number of needles (r = 0.746; p < 0.0005). At a median followup of 16 months, 4 of 42 patients (9.5%) had local recurrences.ConclusionsOur study shows compliance with ICRU 58 recommendations along with certain deviations. Local recurrence rate is acceptable. TRAK shows correlation with surface isodose in MUPIT-based brachytherapy and should to be evaluated in future studies.  相似文献   
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