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   284篇
  免费   40篇
  国内免费   1篇
儿科学   21篇
妇产科学   3篇
基础医学   54篇
口腔科学   4篇
临床医学   23篇
内科学   46篇
皮肤病学   7篇
神经病学   13篇
特种医学   16篇
外科学   40篇
综合类   8篇
预防医学   11篇
眼科学   1篇
药学   5篇
肿瘤学   73篇
  2023年   2篇
  2022年   4篇
  2021年   8篇
  2020年   4篇
  2019年   5篇
  2018年   12篇
  2017年   8篇
  2016年   10篇
  2015年   13篇
  2014年   9篇
  2013年   19篇
  2012年   23篇
  2011年   19篇
  2010年   20篇
  2009年   11篇
  2008年   18篇
  2007年   12篇
  2006年   13篇
  2005年   8篇
  2004年   6篇
  2003年   10篇
  2002年   9篇
  2001年   5篇
  2000年   4篇
  1999年   8篇
  1998年   5篇
  1997年   7篇
  1996年   1篇
  1995年   6篇
  1993年   7篇
  1992年   3篇
  1991年   2篇
  1990年   5篇
  1989年   4篇
  1988年   4篇
  1987年   3篇
  1986年   2篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   3篇
  1981年   2篇
  1975年   1篇
  1973年   1篇
  1968年   1篇
  1966年   1篇
  1954年   1篇
  1952年   1篇
  1940年   1篇
排序方式: 共有325条查询结果,搜索用时 312 毫秒
81.
Rand  JH; Gordon  RE; Sussman  II; Chu  SV; Solomon  V 《Blood》1982,60(3):627-634
We have localized factor-VIII-related antigen, using immunofluorescence and electron microscopy, in adult human blood vessels. In addition to its presence in endothelial cells, the antigen was localized within subendothelium and the layers of elastic lamina closest to the lumen. Also, we provide the first morphological evidence that factor-VIII- related antigen is associated with collagen fibrils within the vessel wall. These studies suggest that this subendothelial factor-VIII- related antigen may play a role in the adhesion of platelets to subendothelial components following endothelial injury.  相似文献   
82.
83.
84.

Background  

Imprisonment may lead to the development of mental illness, especially depression. This study examines the clinical and sociodemographic profiles of imprisoned women, identifies indicative signs of depression, and relates these indicators to other variables.  相似文献   
85.
86.
To evaluate the therapeutic potential of the newly developed proton pump inhibitor lansoprazole in patients with reflux oesophagitis, we performed a double-blind randomized clinical trial comparing 20 mg omeprazole and 30 mg lansoprazole, involving 229 patients at 9 Scandinavian hospitals. The treatment period was 4 or 8 weeks, and main efficacy variables were healing of endoscopic changes, relief of reflux symptoms, and occurrence of adverse events. No significant difference in terms of healing was found, either after 4 or after 8 weeks' treatment. Patients receiving lansoprazole experienced a greater improvement in heartburn after 4 weeks (p = 0.03), and there was a similar trend for acid regurgitation. Lansoprazole was found to be an effective and safe alternative to omeprazole in short-term treatment of moderate reflux oesophagitis.  相似文献   
87.
Breast-cancer stem cells-beyond semantics   总被引:1,自引:0,他引:1  
Intratumoral heterogeneity in breast cancer is well documented. Although the mechanisms leading to this heterogeneity are not understood, a subpopulation of cancer cells, cancer stem cells (CSCs), that have some phenotypic similarities with adult tissue stem cells, has been suggested to contribute to tumour heterogeneity. It has been postulated that these CSCs are dormant, and by virtue of their low proliferative activity and ability to exclude intracellular toxins, are resistant to chemotherapy and radiation therapy. These cells were initially isolated based on the presence of markers such as CD44, CD24, and ALDH1, with further characterisation using mammosphere assay and transplantation into immunodeficient mice. The CSC hypothesis raises several theoretical and practical questions. Does cancer arise in normal mammary stem cells or do some malignant cells acquire a CSC phenotype through clonal evolution? Are CSCs in different molecular (intrinsic) subtypes of breast cancer similar, or do they have distinct properties based on the subtype? Does the CSC phenotype reflect plasticity or the dynamic nature of a few cancer cells? How do these cells acquire invasive behaviour, as they go through epithelial-to-mesenchymal transition and then revert to epithelial phenotype at sites of metastasis in response to tumour microenvironmental and metastasis site-specific cues? It is increasingly recognised that the methods and assays used for identifying CSCs have substantial limitations; does this negate the entire concept? In this Personal View, we argue that the CSC phenotype represents an aggressive clone that survives in an adverse environment through constant evolution and integration of various hallmarks of cancer. This evolution could involve acquiring mutations that permit asymmetric and symmetric division, converting the host immune attack to its own advantage, and plasticity to adapt to sites of metastasis through reversible change in adhesion molecules. We also argue that the cell-type origin of cancer could affect the rate at which CSCs develop in a tumour, with an eventual effect on disease outcome.  相似文献   
88.
Aberrant activation of the mammalian target of rapamycin (mTOR) signaling plays an important role in breast cancer progression and represents a potential therapeutic target for breast cancer. In this study, we report the impact of the investigational drug MLN0128, a potent and selective small molecule active-site TORC1/2 kinase inhibitor, on tumor growth and metastasis using human breast cancer xenograft models. We assessed in vitro antiproliferative activity of MLN0128 in a panel of breast cancer cell lines. We next evaluated the impact of MLN0128 on tumor growth, angiogenesis and metastasis using mammary fat pad xenograft models of a non-VEGF (ML20) and a VEGF-driven (MV165) MCF-7 sublines harboring PIK3CA mutations. MLN0128 potently inhibited cell proliferation in various breast cancer cell lines harboring PIK3CA (IC50: 1.5?C53?nM), PTEN (IC50: 1?C149?nM), KRAS, and/or BRAF mutations (IC50: 13?C162?nM), and in human endothelial cells (IC50: 33?C40?nM) in vitro. In vivo, MLN0128 decreased primary tumor growth significantly in both non-VEGF (ML20; p?=?0.05) and VEGF-driven MCF-7 (MV165; p?=?0.014) xenograft models. MLN0128 decreased the phosphorylation of Akt, S6, 4E-BP1, and NDRG1 in both models. In contrast, rapamycin increased Akt activity and failed to reduce the phosphorylation of 4E-BP1, PRAS40, and NDRG1. VEGF-induced lung metastasis in MV165 is inhibited by MLN0128 and rapamycin. In conclusion, MLN0128 inhibits TORC1/2-dependent signaling in preclinical models of breast cancer. MLN0128 appears to be superior in blocking mTORC1/2 signaling in contrast to rapamycin. Our findings support the clinical research of MLN0128 in patients with breast cancer and metastasis.  相似文献   
89.
EGFR signalling pathways appear involved in endocrine therapy resistance in breast cancer. This trial estimates the antitumor efficacy and toxicity of the EGFR tyrosine kinase inhibitor gefitinib in combination with anastrozole or fulvestrant in postmenopausal hormone receptor positive breast cancer. Subjects with estrogen receptor and/or PgR positive, metastatic breast cancer were randomized into this phase II study of gefitinib (initial dose was 500 mg orally daily, due to high rate of diarrhea, starting dose was reduced to 250 mg orally daily) with either anastrozole 1 mg daily or fulvestrant 250 mg every 4 weeks. The primary endpoint was clinical benefit (complete responses plus partial responses plus stable disease for 6 months or longer). 141 eligible subjects were enrolled, 72 in the anastrozole plus gefitinib arm, and 69 in the fulvestrant plus gefitinib arm. Anastrozole plus gefitinib had a clinical benefit rate of 44% [95% confidence interval (CI) 33-57%] and fulvestrant plus gefitinib 41% (95% CI 29-53%). Median progression-free survival was 5.3 months (95% CI 3.1-10.4) versus 5.2 months (95% CI 2.9-8.2) for anastrozole plus gefitinib versus fulvestrant plus gefitinib, respectively. Median survival was 30.3 months (95% CI 21.2-38.9+) versus 23.9 months (95% CI 15.4-33.5) for anastrozole plus gefitinib versus fulvestrant plus gefitinib, respectively. In general, the toxicity is greater than expected for single agent endocrine therapy alone. Anastrozole plus gefitinib and fulvestrant plus gefitinib have similar clinical benefit rates in the treatment of estrogen and/or PgR positive metastatic breast cancer, and the rates of response are not clearly superior to gefitinib or endocrine therapy alone. Further studies of EGFR inhibition plus endocrine therapy do not appear warranted, but if performed should include attempts to identify biomarkers predictive of antitumor activity.  相似文献   
90.
The present study was performed to evaluate the significance of biologic subtype and 21-gene recurrence score relative to local recurrence and local-regional recurrence after breast conservation treatment with radiation. Eastern Cooperative Oncology Group E2197 was a prospective randomized clinical trial that compared two adjuvant systemic chemotherapy regimens for patients with operable breast carcinoma with 1-3 positive lymph nodes or negative lymph nodes with tumor size >1.0 cm. The study population was a subset of 388 patients with known 21-gene recurrence score and treated with breast conservation surgery, systemic chemotherapy, and definitive radiation treatment. Median follow-up was 9.7 years (range = 3.7-11.6 years). The 10-year rates of local recurrence and local-regional recurrence were 5.4 % and 6.6 %, respectively. Neither biologic subtype nor 21-gene Recurrence Score was associated with local recurrence or local-regional recurrence on univariate or multivariate analyses (all P ≥ 0.12). The 10-year rates of local recurrence were 4.9 % for hormone receptor positive, HER2-negative tumors, 6.0 % for triple negative tumors, and 6.4 % for HER2-positive tumors (P = 0.76), and the 10-year rates of local-regional recurrence were 6.3, 6.9, and 7.2 %, respectively (P = 0.79). For hormone receptor-positive tumors, the 10-year rates of local recurrence were 3.2, 2.9, and 10.1 % for low, intermediate, and high 21-gene recurrence score, respectively (P = 0.17), and the 10-year rates of local-regional recurrence were 3.8, 5.1, and 12.0 %, respectively (P = 0.12). For hormone receptor-positive tumors, the 21-gene recurrence score evaluated as a continuous variable was significant for local-regional recurrence (hazard ratio 2.66; P = 0.03). The 10-year rates of local recurrence and local-regional recurrence were reasonably low in all subsets of patients. Neither biologic subtype nor 21-gene recurrence score should preclude breast conservation treatment with radiation.  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