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   4127篇
  免费   281篇
  国内免费   50篇
耳鼻咽喉   53篇
儿科学   67篇
妇产科学   64篇
基础医学   538篇
口腔科学   76篇
临床医学   356篇
内科学   1062篇
皮肤病学   132篇
神经病学   377篇
特种医学   176篇
外科学   659篇
综合类   22篇
一般理论   5篇
预防医学   166篇
眼科学   58篇
药学   238篇
中国医学   8篇
肿瘤学   401篇
  2023年   47篇
  2022年   32篇
  2021年   153篇
  2020年   104篇
  2019年   140篇
  2018年   157篇
  2017年   127篇
  2016年   141篇
  2015年   154篇
  2014年   166篇
  2013年   256篇
  2012年   419篇
  2011年   349篇
  2010年   199篇
  2009年   156篇
  2008年   300篇
  2007年   251篇
  2006年   248篇
  2005年   243篇
  2004年   199篇
  2003年   185篇
  2002年   168篇
  2001年   24篇
  2000年   17篇
  1999年   32篇
  1998年   27篇
  1997年   11篇
  1996年   8篇
  1995年   10篇
  1994年   23篇
  1993年   8篇
  1992年   11篇
  1991年   8篇
  1990年   8篇
  1989年   10篇
  1988年   4篇
  1987年   5篇
  1986年   9篇
  1985年   7篇
  1984年   6篇
  1983年   6篇
  1982年   4篇
  1981年   5篇
  1980年   3篇
  1979年   4篇
  1977年   2篇
  1976年   2篇
  1974年   2篇
  1963年   1篇
  1959年   1篇
排序方式: 共有4458条查询结果,搜索用时 15 毫秒
1.
2.

Background

Radium 223 was introduced for metastatic castration-resistant prostate cancer based on the results of a randomized controlled trial showing risk reduction for death and skeletal events. Our aim was to evaluate the outcome of patients receiving radium 223 in a real-world setting.

Patients and Methods

We conducted a multicenter retrospective analysis in the Triveneto region of Italy.

Results

One hundred fifty-eight patients received radium 223 in our region. After a median follow-up of 9.5 months, 75 patients died. The median overall survival (OS) was 14.2 months, and the median progression-free survival (PFS) was 6.2 months. Seventy-one (45%) patients achieved progression as best response. Thirty-seven (23%) patients stopped the treatment early because of progression. Eastern Cooperative Oncology Group performance status was prognostic for OS (18.4 vs. 12.3 vs. 7.5 months; 0 vs. 1, P = .0062; 0 vs. 2, P = .0002), whereas previous prostatectomy or docetaxel exposure were not. A neutrophil to lymphocytes ratio ≥ 3 significantly impacted OS (18.1 vs. 9.7 months; P < .001) and slightly impacted PFS (6.6 vs. 5.6 months; P = .05). Patients with a baseline alkaline phosphatase (ALP) value ≥ 220 U/L had worse OS and PFS (24.1 vs. 10.5 months; 7.2 vs. 5.5 months; P < .001). Patients with changes in ALP value achieved better OS (P = .029) and PFS (P = .002). There was no difference according to the line of therapy (0 vs. ≥ 1; P = .490). The main grade 3/4 toxicities were anemia, asthenia, and thrombocytopenia.

Conclusion

This large real-world report confirms comparable OS and PFS data when compared with the pivotal study, as well as the predictive role of ALP and neutrophil to lymphocytes ratio. The definition of the optimal position of radium 223 in the treatment of metastatic castration-resistant prostate cancer has still to be defined.  相似文献   
3.
BackgroundHepatobiliary resections are challenging due to the complex liver anatomy. Three-dimensional printing (3DP) has gained popularity due to its ability to produce anatomical models based on the characteristics of each patient.MethodsA multicenter study was conducted on complex hepatobiliary tumours. The endpoint was to validate 3DP model accuracy from original image sources for application in the teaching, patient-communication, and planning of hepatobiliary surgery.ResultsThirty-five patients from eight centers were included. Process testing between 3DP and CT/MRI presented a considerable degree of similarity in vascular calibers (0.22 ± 1.8 mm), and distances between the tumour and vessel (0.31 ± 0.24 mm). The Dice Similarity Coefficient was 0.92, with a variation of 2%. Bland–Altman plots also demonstrated an agreement between 3DP and the surgical specimen with the distance of the resection margin (1.15 ± 1.52 mm). Professionals considered 3DP at a positive rate of 0.89 (95%CI; 0.73–0.95). According to student's distribution a higher success rate was reached with 3DP (median:0.9, IQR: 0.8–1) compared with CT/MRI or 3D digital imaging (P = 0.01).Conclusion3DP hepatic models present a good correlation compared with CT/MRI and surgical pathology and they are useful for education, understanding, and surgical planning, but does not necessarily affect the surgical outcome.  相似文献   
4.

Purpose

Transamniotic stem cell therapy (TRASCET) with select mesenchymal stem cells (MSCs) has been shown to induce partial or complete skin coverage of spina bifida in rodents. Clinical translation of this emerging therapy hinges on its efficacy in larger animal models. We sought to study TRASCET in a model requiring intra-amniotic injections 60 times larger than those performed in the rat.

Methods

Rabbit fetuses (n?=?65) with surgically created spina bifida were divided into three groups. One group (untreated) had no further manipulations. Two groups received volume-matched intra-amniotic injections of either saline or a concentrated suspension of amniotic fluid MSCs (afMSCs) at the time of operation. Infused afMSCs consisted of banked heterologous rabbit afMSCs with mesenchymal identity confirmed by flow cytometry, labeled with green fluorescent protein. Defect coverage at term was blindly categorized only if the presence of a distinctive neoskin was confirmed histologically. Statistical comparisons were by logistic regression and the likelihood ratio test.

Results

Among survivors with spina bifida (n?=?19), there were statistically significant higher rates of defect coverage (all partial) in the afMSC group when compared with the saline and untreated groups (0–50%; p?=?0.022–0.036), with no difference between the saline and untreated groups (p?=?1.00). Donor afMSCs were identified locally, though sparsely and not in the neoskin.

Conclusions

Concentrated intra-amniotic injection of amniotic mesenchymal stem cells can induce partial coverage of experimental spina bifida in a leporine model. Transamniotic stem cell therapy may become a feasible strategy in the prenatal management of spina bifida.

Level of Evidence

N/A (animal and laboratory study).  相似文献   
5.
6.
7.
8.
9.
10.
Objective: To examine the relationship between reflection, gender, residency choice, word count, and academic achievement among medical students.

Methods: A modified version of the Reflection Evaluation for Learners’ Enhanced Competencies Tool (REFLECT) was developed and used for this study (Cronbach’s alpha of 0.86 with an intraclass correlation coefficient [ICC] of 0.68). This was applied to writing samples about professionalism in gross anatomy from first-year medical students between 2005 and 2011. Four analysts reviewed and scored written reflections independently. Composite reflection scores were compared with gender, residency choice, length of written reflection, NBME® Gross Anatomy and Embryology Subject Examination scores, and final gross anatomy course.

Results: Total of 319 written reflections were evaluated. Female students who pursued medicine specialties had the highest composite reflection scores (87 [27.2%]). Word count frequently correlated with reflection score (p?<?0.0001). Students who performed well on the NBME® Gross Anatomy and Embryology Subject Examination tended to achieve high anatomy course grades (p?<?0.0001). There was no statistically significant relationship between composite reflection scores and NBME® Gross Anatomy and Embryology Subject Examination scores (p?=?0.16) or anatomy course grades (p?=?0.90).

Conclusions: This study suggests there are likely no correlations between reflective capacity and academic performance on tests of medical knowledge administered early in the medical curriculum.  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