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   147541篇
  免费   10952篇
  国内免费   292篇
耳鼻咽喉   1381篇
儿科学   3944篇
妇产科学   2995篇
基础医学   22870篇
口腔科学   3806篇
临床医学   12607篇
内科学   30113篇
皮肤病学   2498篇
神经病学   14677篇
特种医学   6202篇
外国民族医学   16篇
外科学   19103篇
综合类   649篇
现状与发展   1篇
一般理论   110篇
预防医学   15867篇
眼科学   2481篇
药学   8848篇
中国医学   261篇
肿瘤学   10356篇
  2023年   647篇
  2022年   964篇
  2021年   2383篇
  2020年   1760篇
  2019年   2508篇
  2018年   3103篇
  2017年   2653篇
  2016年   2902篇
  2015年   3270篇
  2014年   4341篇
  2013年   5803篇
  2012年   8868篇
  2011年   8942篇
  2010年   4654篇
  2009年   4856篇
  2008年   7982篇
  2007年   8135篇
  2006年   7872篇
  2005年   7425篇
  2004年   6342篇
  2003年   6027篇
  2002年   5494篇
  2001年   4857篇
  2000年   4799篇
  1999年   4298篇
  1998年   1838篇
  1997年   1519篇
  1996年   1566篇
  1995年   1293篇
  1994年   1214篇
  1993年   1109篇
  1992年   2935篇
  1991年   2641篇
  1990年   2516篇
  1989年   2370篇
  1988年   2153篇
  1987年   1910篇
  1986年   1826篇
  1985年   1738篇
  1984年   1246篇
  1983年   1106篇
  1982年   619篇
  1981年   548篇
  1980年   464篇
  1979年   968篇
  1978年   599篇
  1977年   497篇
  1974年   506篇
  1973年   486篇
  1972年   438篇
排序方式: 共有10000条查询结果,搜索用时 615 毫秒
1.
2.
Intratumor heterogeneity is a main cause of the dismal prognosis of glioblastoma (GBM). Yet, there remains a lack of a uniform assessment of the degree of heterogeneity. With a multiscale approach, we addressed the hypothesis that intratumor heterogeneity exists on different levels comprising traditional regional analyses, but also innovative methods including computer-assisted analysis of tumor morphology combined with epigenomic data. With this aim, 157 biopsies of 37 patients with therapy-naive IDH-wildtype GBM were analyzed regarding the intratumor variance of protein expression of glial marker GFAP, microglia marker Iba1 and proliferation marker Mib1. Hematoxylin and eosin stained slides were evaluated for tumor vascularization. For the estimation of pixel intensity and nuclear profiling, automated analysis was used. Additionally, DNA methylation profiling was conducted separately for the single biopsies. Scoring systems were established to integrate several parameters into one score for the four examined modalities of heterogeneity (regional, cellular, pixel-level and epigenomic). As a result, we could show that heterogeneity was detected in all four modalities. Furthermore, for the regional, cellular and epigenomic level, we confirmed the results of earlier studies stating that a higher degree of heterogeneity is associated with poorer overall survival. To integrate all modalities into one score, we designed a predictor of longer survival, which showed a highly significant separation regarding the OS. In conclusion, multiscale intratumor heterogeneity exists in glioblastoma and its degree has an impact on overall survival. In future studies, the implementation of a broadly feasible heterogeneity index should be considered.  相似文献   
3.
4.
5.
6.

Objective

Comparative survival between neoadjuvant chemotherapy and adjuvant chemotherapy for patients with cT2-4N0-1M0 non–small cell lung cancer has not been extensively studied.

Methods

Patients with cT2-4N0-1M0 non–small cell lung cancer who received platinum-based chemotherapy were retrospectively identified. Exclusion criteria included stage IV disease, induction radiotherapy, and targeted therapy. The primary end point was disease-free survival. Secondary end points were overall survival, chemotherapy tolerance, and ability of Response Evaluation Criteria In Solid Tumors response to predict survival. Survival was estimated using the Kaplan–Meier method, compared using the log-rank test and Cox proportional hazards models, and stratified using matched pairs after propensity score matching.

Results

In total, 330 patients met the inclusion criteria (n = 92/group after propensity-score matching; median follow-up, 42 months). Five-year disease-free survival was 49% (95% confidence interval, 39-61) for neoadjuvant chemotherapy versus 48% (95% confidence interval, 38-61) for adjuvant chemotherapy (P = .70). On multivariable analysis, disease-free survival was not associated with neoadjuvant chemotherapy or adjuvant chemotherapy (hazard ratio, 1.1; 95% confidence interval, 0.64-1.90; P = .737), nor was overall survival (hazard ratio, 1.21; 95% confidence interval, 0.63-2.30; P = .572). The neoadjuvant chemotherapy group was more likely to receive full doses and cycles of chemotherapy (P = .014/0.005) and had fewer grade 3 or greater toxicities (P = .001). Response Evaluation Criteria In Solid Tumors response to neoadjuvant chemotherapy was associated with disease-free survival (P = .035); 15% of patients receiving neoadjuvant chemotherapy (14/92) had a major pathologic response.

Conclusions

Timing of chemotherapy, before or after surgery, is not associated with an improvement in overall or disease-free survival among patients with cT2-4N0-1M0 non–small cell lung cancer who undergo complete surgical resection.  相似文献   
7.
8.
9.
10.
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