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   2662篇
  免费   421篇
  国内免费   76篇
耳鼻咽喉   19篇
儿科学   73篇
妇产科学   78篇
基础医学   434篇
口腔科学   32篇
临床医学   210篇
内科学   299篇
皮肤病学   27篇
神经病学   162篇
特种医学   116篇
外国民族医学   2篇
外科学   377篇
综合类   286篇
预防医学   153篇
眼科学   12篇
药学   136篇
  3篇
中国医学   114篇
肿瘤学   626篇
  2024年   4篇
  2023年   38篇
  2022年   68篇
  2021年   166篇
  2020年   158篇
  2019年   149篇
  2018年   161篇
  2017年   139篇
  2016年   157篇
  2015年   134篇
  2014年   227篇
  2013年   214篇
  2012年   169篇
  2011年   149篇
  2010年   135篇
  2009年   122篇
  2008年   152篇
  2007年   108篇
  2006年   110篇
  2005年   82篇
  2004年   61篇
  2003年   50篇
  2002年   60篇
  2001年   46篇
  2000年   33篇
  1999年   31篇
  1998年   25篇
  1997年   32篇
  1996年   22篇
  1995年   20篇
  1994年   24篇
  1993年   12篇
  1992年   16篇
  1991年   16篇
  1990年   10篇
  1989年   10篇
  1988年   8篇
  1987年   8篇
  1986年   6篇
  1985年   5篇
  1984年   5篇
  1983年   6篇
  1982年   5篇
  1981年   1篇
  1980年   3篇
  1978年   1篇
  1975年   1篇
排序方式: 共有3159条查询结果,搜索用时 15 毫秒
1.
PurposeTo assess the safety and tolerability of a vandetanib-eluting radiopaque embolic (BTG-002814) for transarterial chemoembolization (TACE) in patients with resectable liver malignancies.Materials and MethodsThe VEROnA clinical trial was a first-in-human, phase 0, single-arm, window-of-opportunity study. Eligible patients were aged ≥18 years and had resectable hepatocellular carcinoma (HCC) (Child-Pugh A) or metastatic colorectal cancer (mCRC). Patients received 1 mL of BTG-002814 transarterially (containing 100 mg of vandetanib) 7–21 days prior to surgery. The primary objectives were to establish the safety and tolerability of BTG-002814 and determine the concentrations of vandetanib and the N-desmethyl vandetanib metabolite in the plasma and resected liver after treatment. Biomarker studies included circulating proangiogenic factors, perfusion computed tomography, and dynamic contrast-enhanced magnetic resonance imaging.ResultsEight patients were enrolled: 2 with HCC and 6 with mCRC. There was 1 grade 3 adverse event (AE) before surgery and 18 after surgery; 6 AEs were deemed to be related to BTG-002814. Surgical resection was not delayed. Vandetanib was present in the plasma of all patients 12 days after treatment, with a mean maximum concentration of 24.3 ng/mL (standard deviation ± 13.94 ng/mL), and in resected liver tissue up to 32 days after treatment (441–404,000 ng/g). The median percentage of tumor necrosis was 92.5% (range, 5%–100%). There were no significant changes in perfusion imaging parameters after TACE.ConclusionsBTG-002814 has an acceptable safety profile in patients before surgery. The presence of vandetanib in the tumor specimens up to 32 days after treatment suggests sustained anticancer activity, while the low vandetanib levels in the plasma suggest minimal release into the systemic circulation. Further evaluation of this TACE combination is warranted in dose-finding and efficacy studies.  相似文献   
2.
BackgroundIntraabdominal and retroperitoneal sarcomas (IaRS) are malignant connective tissue tumors. Surgical resection is often the only curative treatment. The primary objective was to report the mid-term outcomes following contemporary treatment protocols and identify prognostic factors.MethodsA retrospective review of consecutive patients (n = 107) with IaRS treated at single center from 2013 until 2018 was conducted. Histological diagnosis, tumor grade, perioperative complications, mortality, and long-time survival were registered and retrieved from patient records. Primary and recurrent tumors were analyzed separately.ResultsA total of 107 patients were identified. Median follow-up time was 3.5 years. Thirty-day mortality was 3.4% and 90-day mortality was 5.6% for all tumors. The major complication rate was 18%. The 5-year estimated survival for primary and recurrent tumors was 55.4% and 48.4%, respectively. Multifocal disease was evident in 32% of the patient cohort, and 58% of patients in the recurrent group. Multivariate analysis for survival revealed a hazard ratio (HR) of 3.1 (95% CI 1.68–8.41) for multifocality, HR 2.9 (95% CI 1.28–6.98) for Clavien-Dindo grade, HR 2.3 (95% CI 1.21–4.31) for tumor grades 2 or 3, and HR 1.002 (95% CI 1.001–1.004) for surgical margins.ConclusionsOur study found overall acceptable morbidity and mortality, and identified prognostic markers for overall survival. Recurrent tumors were not associated with worse survival. Multifocality is associated with a worse overall survival. The prognostic factors identified were; tumor grade, multifocality, intralesional margins and postoperative complications.  相似文献   
3.
目的通过对2019年2月-2019年6月在西安交通大学第二附属医院实习的大学四年级及大学五年级的临床医学专业的医学生就业意向及就业情况的分析,研究住院医师规范化培训制度对医学生就业的影响。方法运用自制的问卷进行匿名填写的方式对大学四年级、大学五年级的临床医学本科生及5+3模式的规范化培训医学生进行调查。结果大部分医学生选择继续升学,选择就业的学生多愿意留在大城市就业,选择住院医师规范化培训的学生只占极少数。结论做好住院医师规范化培训政策的宣传,落实各项优惠政策,鼓励学生进行住院医师规范化培训及到基层工作,引导学生理性考研,是目前社会及医学院校就业指导中的重要内容。  相似文献   
4.
5.
BackgroundGrowth hormone (GH)-producing pituitary tumors account for 10 to 15% of pituitary tumors. The hypersecretion of GH may induce changes in the airway anatomy through the activation of Insulin-like Growth factor 1(IGF-1) pathway. We sought investigate the role IGF-1 as a potential predictive factor of difficult laryngoscopy in patients with GH-producing pituitary adenoma.MethodsThis study was a single center retrospective study. We included 33 patients undergoing transsphenoidal resection of GH-producing pituitary. We recorded demographic data, el-Ganzouri risk index (EGRI) and modified Look-Evaluate-Mallampati-Obstruction-Neck mobility (mLEMON) score, and pituitary hormone plasma levels. We performed ordinal logistic regression to analyze the relationship between IGF-1 and EGRI, mLEMON, and Cormack-Lehane Grade score and a multiple logistic regression to test the capability of EGRI, mLEMON and IGF-1 levels to predict Cormack-Lehane score. Receiver operating curve (ROC), area under the curve (AUC), and cut-off value of IGF-1 were calculated.ResultsOnly 14 (42.8%) and 12 (36.36%) patients showed predictive factors of difficult intubation according to EGRI and mLEMON score, respectively. IGF-1 significantly correlated with Cormack-Lehane (p = 0.005879) but not with mLEMON and EGRI (p = 0.3080 and 0.4146, respectively). In multiple regression model IGF-1 correlated only with Cormack-Lehane grade (p = 0.0089). Area under ROC was 0.8571 and cut-off value of IGF-1 was 186.15 ng/ml.ConclusionHigher IGF-1 levels correlate with the probability of having a higher Cormack-Lehane score; classical bedside scores, such as mLEMON and EGRI, were not able to predict difficult laryngoscopy in our population.  相似文献   
6.
7.
8.

Background

In colorectal cancer liver metastases (CRCLM), bevacizumab-based neoadjuvant strategies provide increased pathologic response. We aimed at assessing the activity of perioperative capecitabine, oxaliplatin, irinotecan, and bevacizumab (COI-B regimen) in patients with potentially resectable CRCLM, and investigating biomarkers for early prediction of pathologic response.

Patients and Methods

This was a single-center phase II study enrolling patients with liver-limited, borderline resectable disease and/or high-risk features. Patients received 5 preoperative and 4 postoperative cycles of biweekly COI-B (irinotecan 180 mg/m2 and bevacizumab 5 mg/Kg on day 1, oxaliplatin 85 mg/m2 on day 2, and capecitabine 1000 mg/m2 twice a day on days 2 to 6). The primary endpoint was pathologic response rate in the intention-to-treat population. A Simon 2-stage design was adopted to detect an increase from 30% to 50% with a power of 90%. Dynamic imaging biomarkers (early tumor shrinkage [ETS], deepness of response, maximum standardized uptake volume [SUVmax]/regression index) and next generation sequencing data were explored as surrogates.

Results

From June 2013 to March 2017, 46 patients were enrolled. Pathologic response was achieved in 63% patients (endpoint met), and responders achieved significantly better survival outcomes with respect to non-responders. The most frequent grade 3/4 adverse events were diarrhea and neutropenia (8.7%) in the preoperative phase and thromboembolic events (5.9%) in the postoperative phase. ETS and lower SUV-2 were significantly associated with pathologic response.

Conclusion

The COI-B regimen is a feasible and highly active perioperative strategy in patients with molecularly unselected, potentially resectable CRCLM. ETS and SUV-2 have a promising role as imaging-based biomarkers for pathologic response.  相似文献   
9.
张瑞  曹庆伟  李科  秦雪梅 《中草药》2020,51(2):451-460
目的通过分析黄芪AstragaliRadix药材的性状以及黄酮类化学成分与绝对生长年限的相关性,明确黄芪根的生长年限是引起黄芪药材性状和化学差异性的主要因素。方法收集不同产地、不同等级的黄芪药材,对其外观形态定性描述,长度、直径定量测定,并采用徒手切片法观察不同等级仿野生芪的生长年限分布,观察其分布规律。采用UPLC-UV法,色谱柱为Ultimate C18(250 mm×4.6 mm,5μm),柱温30℃,体积流量为1 mL/min,检测波长230 nm,进样量20μL,乙腈-水梯度洗脱,建立了24批不同产地黄芪药材黄酮类成分HPLC-UV指纹图谱,并对不同等级仿野生芪和栽培芪5种黄酮类成分进行含量测定。结果将不同生长方式的黄芪药材划分为仿野生芪和栽培芪2个规格。特等黄芪主要是5年以上生长年限的根段,一等主要是4~5年生的根段,二等主要是3~4年生的根段,三等主要是2~3年生的根段,四等主要是1~2年生的根段。不同产地、不同等级黄芪指纹图谱中指认出5个共有峰,采用相似度评价软件分析,以仿野生芪图谱为参照,仿野生芪样品相似度为0.892~0.994,栽培芪样品相似度为0.274~0.531,主成分分析和聚类分析均显示仿野生芪和栽培芪可以明显分成2类。仿野生芪5种黄酮类成分含量明显高于栽培芪,仿野生芪(除特等外)总黄酮含量与等级(或直径、年限)呈正相关,栽培芪与等级不相关。结论本研究为黄芪药材商品规格等级标准的制定提供科学依据,为进一步构建黄芪药材质量等级标准奠定基础。  相似文献   
10.
Background: The standard of care in high grade glioma (HGG) is maximal safe surgical resection followed by adjuvant radiotherapy (RT) with/without chemotherapy. For anaplastic gliomas, studies have shown use of procarbazine, lomustine, vincristine (PCV) improves overall survival (OS) and progression free survival (PFS). Currently, there is substantial evidence that molecular markers strongly predict prognosis and response to treatment. Methods: Between January 2016 to January 2018, 42 patients were accrued and followed up till April 2019. The primary end points were to correlate molecular markers with response to therapy in terms of OS and PFS in HGG. The secondary end point was to evaluate frequency of 1p/19q codeletion, IDH 1 mutation, ATRX deletion and p53 in HGG patients. Results: The median age was 46 years (range 18-67) with M:F ratio 30:12. The frequency of IDH1 mutation,1p/19q codeletion, p53 mutation and ATRX mutation were 42.8%, 16.6%, 42.8% and 14.2% respectively. All the seven patients with 1p/19q codeletion had IDH1 mutation. Median follow up was 22 months. The 20-months PFS for different mutations were as follows; IDH1-mutated vs wild type: 53.6% vs 29.8%; p-0.035, 1p/19q codeleted vs non-codeleted: 85.7% vs 62.3%; p-0.011, p53 wild type vs mutated 32.1% vs 35.6%; p-0.035 and ATRX lost vs retained: 55.6% vs 53.3%; p- 0.369. The 20-months OS for IDH1 mutated vs wild type: 82.4% vs 30.6%; p-0.014, 1p/19q codeleted vs non-codeleted: 85.7% vs 65.8%; p-0.104, p53 wild-type vs mutated 45.5% vs 73.9%; p-0.036 and ATRX lost vs retained: 100% vs 60.3%; p-0.087. Conclusion: Codeletion of 1p/19q with IDH1 mutation in HGG is associated with a significantly favourable PFS. However, larger studies with longer follow up are required to evaluate OS and PFS in all the molecular subgroups.  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