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   6095篇
  免费   386篇
  国内免费   8篇
耳鼻咽喉   41篇
儿科学   324篇
妇产科学   165篇
基础医学   760篇
口腔科学   50篇
临床医学   1302篇
内科学   803篇
皮肤病学   68篇
神经病学   476篇
特种医学   148篇
外科学   374篇
综合类   88篇
一般理论   14篇
预防医学   883篇
眼科学   96篇
药学   509篇
  1篇
中国医学   10篇
肿瘤学   377篇
  2023年   31篇
  2022年   38篇
  2021年   62篇
  2020年   46篇
  2019年   111篇
  2018年   123篇
  2017年   85篇
  2016年   103篇
  2015年   99篇
  2014年   132篇
  2013年   285篇
  2012年   425篇
  2011年   446篇
  2010年   253篇
  2009年   162篇
  2008年   417篇
  2007年   427篇
  2006年   401篇
  2005年   443篇
  2004年   408篇
  2003年   365篇
  2002年   415篇
  2001年   33篇
  2000年   42篇
  1999年   33篇
  1998年   87篇
  1997年   82篇
  1996年   61篇
  1995年   69篇
  1994年   64篇
  1993年   56篇
  1992年   36篇
  1991年   32篇
  1990年   35篇
  1989年   27篇
  1988年   27篇
  1987年   21篇
  1986年   27篇
  1985年   35篇
  1984年   51篇
  1983年   38篇
  1982年   72篇
  1981年   42篇
  1980年   39篇
  1979年   29篇
  1978年   32篇
  1977年   25篇
  1976年   22篇
  1974年   19篇
  1972年   15篇
排序方式: 共有6489条查询结果,搜索用时 15 毫秒
21.
BackgroundIn vivo studies demonstrate that curcumin increases radioresponse of colorectal cancers. To demonstrate efficacy in humans, we performed a randomized double-blind study of locally advanced rectal cancer (LARC) patients receiving pre-operative chemoradiation therapy (CRT) ± curcumin. We used pathologic complete response (pCR) rate as a surrogate for clinical outcome.MethodsFrom 2008–2010, LARC patients were randomized to placebo/curcumin in a 1:2 ratio. Patients received CRT [50.4 gray in 28 fractions; capecitabine (825 mg/m2 twice daily)] followed by surgery. Curcumin (4 grams orally, twice daily) or placebo was given throughout CRT and 6 weeks afterward. Toxicity was monitored weekly. Blood samples taken pre- and 1-hour post-ingestion and tissue biopsies (both collected at CRT week 2) were analyzed for pharmacokinetics. The primary outcome was surgical pCR rate.ResultsOf 22 enrolled patients, 15 received curcumin. Median age was 61 years and the majority were male (n=13; 59%). The median serum curcumin concentrations before (3.04 ng/mL; range, 1.24–18.88 ng/mL) and 1 hour after (3.32 ng/mL; range, 0.84–5.36 ng/mL) curcumin intake did not differ significantly (P=0.33). Serum curcumin concentrations both increased and decreased 1-hour post-administration (range as percentage of baseline: 8.8–258.1%). Twelve curcumin patient tissue biopsies had median curcumin concentration of 33.7 ng/mg tissue (range, 0.1–4,765.7 ng/mg). Two placebo and 1 curcumin patient achieved pCRs (P=0.18). One grade 3 toxicity (infection) was experienced.ConclusionsThe addition of curcumin to CRT did not increase pCR rates for LARC patients. The unpredictable bioavailability of curcumin contributes to continued uncertainties regarding curcumin efficacy.Trial RegistrationClinicalTrials.gov identifier: NCT00745134.  相似文献   
22.
美国临床肿瘤学会(American Society of Clinical Oncology,ASCO)是全球领先的肿瘤专业学术组织,学会宗旨是预防癌症及改善癌症诊疗服务.肿瘤学实践技能改善活动(Quality Oncology Practice Initiative,QOPI)始于2002年,是在ASCO健康服务委员会的指导下,以临床实践为基础的医疗质量改善活动,其目标是帮助肿瘤科医师通过自我检查和改善,促进其诊疗水平的提高.  相似文献   
23.
BackgroundCancer of unknown primary (CUP) comprises a heterogeneous collection of malignancies that are typically associated with a poor prognosis and a lack of effective treatment options. We retrospectively evaluated the clinical utility of targeted next-generation sequencing (NGS) among CUP patients to assist with diagnosis and identify opportunities for molecularly guided therapy.Patients and MethodsPatients with a CUP at Moffitt Cancer Center who underwent NGS between January 1, 2014 and December 31, 2019, were eligible for study inclusion. Next-generation sequencing results were assessed to determine the frequency of clinically actionable molecular alterations, and chart reviews were performed to ascertain the number of patients receiving molecularly guided therapy.ResultsNinety-five CUP patients were identified for analysis. Next-generation sequencing testing identified options for molecularly guided therapy for 55% (n = 52) of patients. Among patients with molecularly guided therapy options, 33% (n = 17) were prescribed a molecularly guided therapy. The median overall survival for those receiving molecularly guided therapy was 23.6 months. Among the evaluable patients, the median duration of treatment for CUP patients (n = 7) receiving molecular-guided therapy as a first-line therapy was 39 weeks. The median duration of treatment for CUP patients (n = 8) treated with molecularly guided therapy in the second- or later-line setting was 13 weeks. Next-generation sequencing results were found to be suggestive of a likely primary tumor type for 15% (n = 14) of patients.ConclusionNext-generation sequencing results enabled the identification of treatment options in a majority of patients and assisted with the identification of a likely primary tumor type in a clinically meaningful subset of patients.  相似文献   
24.
BACKGROUND: For patients receiving home parenteral nutrition (HPN), catheter-related bloodstream infection (CRBSI) and reactive depression may significantly impact quality-of-life. This study evaluated the influence of patient affiliation with a national organization promoting HPN education and peer support on these outcome variables. METHODS: Using a case-control design, we compared 2 groups of affiliated patients with nonaffiliated controls, who were matched for diagnosis, HPN duration, sex, and age. Group 1 data were obtained from patients in large HPN medical practice programs. Group 2 data were obtained from patients in small medical practices with a small number of HPN patients. All participants were evaluated by structured interviews every 6 months over 18 months. RESULTS: In both data collection groups, affiliated patients (A) had significantly higher (mean +/- SD) quality-of-life scores compared with nonaffiliated patients (NA): (Gr 1: A, 19.8 +/- 4.7 versus NA, 17.6 +/- 5.6, p = .05; Gr 2: A, 20.4 +/- 5.2 versus NA, 17.3 +/- 4.8, p = .05). Affiliated patients also had lower depression scores (Gr 1: A, 10.9 +/- 10.4 versus NA, 20.4 +/- 13.6, p = .01; Gr 2: A, 12.5 +/- 9.6 versus NA, 18.5 +/- 10.8, p = .03) and a lower incidence of catheter-related infections (Gr 1: A, 0.10 +/- 0.3 versus NA, 0.60 +/- 0.55, p = .01; Gr 2: A, 0.27 +/- 0.55 versus NA, 0.71 +/- 0.64, p = .02) than nonaffiliated patients. CONCLUSIONS: Affiliation with an organization that provides ongoing HPN education and peer support was associated with significantly better HPN outcomes. Alternative explanations are discussed in relation to limitations of the case-control design.  相似文献   
25.
26.
Thyrotropin-releasing hormone (TRH), 0.1 mg/kg, i.m., significantly counteracted pentobarbital narcosis in six monkeys, but melanocyte-stimulating-hormone-release-inhibiting factor (MIF), 0.1 mg/kg i.m., did not. Earlier dose-response studies in unanesthetized monkeys had shown that this dose of MIF stimulated motor activity; this dose of TRH had shown no stimulant effect, but a higher dose depressed activity. Thus, an MIF dose that stimulates unanesthetized monkeys does not reverse pentobarbital narcosis; a TRH dose that by itself is neither stimulant nor depressant does partially reverse pentobarbital narcosis.  相似文献   
27.
28.
The efficacy of valganciclovir as preemptive therapy for the prevention of cytomegalovirus (CMV) disease and its impact on indirect sequelae of CMV were assessed in recipient-negative/donor-positive (R-/D+) liver transplant recipients. Of 187 consecutive liver transplant recipients at our institution since July 2001, 36 (19.2%) belonged to the R-/D+ group. Surveillance tests for CMV were performed on all patients at weeks 2, 4, 6, 8, 10,12, and 16. In all, 27 patients with asymptomatic viremia received preemptive therapy with valganciclovir. At a total follow-up of 62.8 patient years (median: 19 months, range: 3 months to 5.6 years), no episodes of CMV disease were documented in these patients. The incidence of rejection, retransplantation, and bacterial or fungal infections and the probability of survival did not differ for R-/D+ patients and all non-R-/D+ patients treated preemptively with valganciclovir (P > 0.20 for all variables). Thus, preemptive therapy with valganciclovir in R-/D+ patients was not associated with CMV disease during the period of surveillance monitoring or at anytime thereafter (late-onset CMV disease). The indirect outcomes with the use of valganciclovir in R-/D+ patients were comparable to the outcomes of other subgroups of liver transplant recipients receiving preemptive therapy.  相似文献   
29.
30.
The After Breast Cancer Pooling Project was established to examine the role of physical activity, adiposity, dietary factors, supplement use, and quality of life (QOL) in breast cancer prognosis. This paper presents pooled and harmonized data on post-diagnosis lifestyle factors, clinical prognostic factors, and breast cancer outcomes from four prospective cohorts of breast cancer survivors (three US-based and one from Shanghai, China) for 18,314 invasive breast cancer cases diagnosed between 1976 and 2006. Most participants were diagnosed with stage I-II breast cancer (84.7%). About 60% of breast tumors were estrogen receptor (ER)+/progesterone receptor (PR)+; 21% were ER-/PR-. Among 8,118 participants with information on HER-2 tumor status, 74.8% were HER-2- and 18.5% were HER-2+. At 1-2 years post-diagnosis (on average), 17.9% of participants were obese (BMI ≥ 30 kg/m2), 32.6% were overweight (BMI 25-29 kg/m2), and 59.9% met the 2008 Physical Activity Guidelines for Americans (≥ 2.5 h per week of moderate activity). During follow-up (mean = 8.4 years), 3,736 deaths (2,614 from breast cancer) and 3,564 recurrences have been documented. After accounting for differences in year of diagnosis and timing of post-diagnosis enrollment, five-year overall survival estimates were similar across cohorts. This pooling project of 18,000 breast cancer survivors enables the evaluation of associations of post-diagnosis lifestyle factors, QOL, and breast cancer outcomes with an adequate sample size for investigation of heterogeneity by hormone receptor status and other clinical predictors. The project sets the stage for international collaborations for the investigation of modifiable predictors for breast cancer outcomes.  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