全文获取类型
收费全文 | 4943篇 |
免费 | 257篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 63篇 |
儿科学 | 215篇 |
妇产科学 | 164篇 |
基础医学 | 531篇 |
口腔科学 | 214篇 |
临床医学 | 389篇 |
内科学 | 1119篇 |
皮肤病学 | 92篇 |
神经病学 | 299篇 |
特种医学 | 107篇 |
外科学 | 676篇 |
综合类 | 249篇 |
一般理论 | 18篇 |
预防医学 | 254篇 |
眼科学 | 150篇 |
药学 | 389篇 |
中国医学 | 87篇 |
肿瘤学 | 222篇 |
出版年
2024年 | 3篇 |
2023年 | 35篇 |
2022年 | 129篇 |
2021年 | 268篇 |
2020年 | 119篇 |
2019年 | 160篇 |
2018年 | 213篇 |
2017年 | 100篇 |
2016年 | 124篇 |
2015年 | 184篇 |
2014年 | 211篇 |
2013年 | 261篇 |
2012年 | 361篇 |
2011年 | 434篇 |
2010年 | 224篇 |
2009年 | 199篇 |
2008年 | 307篇 |
2007年 | 248篇 |
2006年 | 272篇 |
2005年 | 253篇 |
2004年 | 249篇 |
2003年 | 192篇 |
2002年 | 221篇 |
2001年 | 58篇 |
2000年 | 29篇 |
1999年 | 46篇 |
1998年 | 32篇 |
1997年 | 27篇 |
1996年 | 26篇 |
1995年 | 15篇 |
1994年 | 20篇 |
1993年 | 14篇 |
1992年 | 18篇 |
1991年 | 17篇 |
1990年 | 15篇 |
1989年 | 19篇 |
1988年 | 15篇 |
1987年 | 11篇 |
1986年 | 12篇 |
1985年 | 4篇 |
1984年 | 9篇 |
1983年 | 10篇 |
1982年 | 16篇 |
1981年 | 13篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 10篇 |
1974年 | 5篇 |
排序方式: 共有5238条查询结果,搜索用时 32 毫秒
41.
42.
The HOPA Gene Dodecamer Duplication Is Not a Significant Etiological Factor in Autism 总被引:3,自引:0,他引:3
Michaelis RC Copeland-Yates SA Sossey-Alaoui K Skinner C Friez MJ Longshore JW Simensen RJ Schroer RJ Stevenson RE 《Journal of autism and developmental disorders》2000,30(4):355-358
A recent study has suggested that a dodecamer duplication in the HOPA gene in Xq13 may occur in a significant portion of male patients with autism. We have determined the incidence of this duplication in 202 patients from the South Carolina Autism Study. The incidence of the duplication was not significantly different between patients and controls. Three of the female patients inherited the duplication from nonautistic fathers. In addition, there was no systematic skewing of X inactivation in the female patients with the duplication, or in nonautistic mothers and sisters with the duplication. These findings suggest that the dodecamer duplication in the HOPA gene does not play a significant role in the etiology of autism. 相似文献
43.
Erythropoietin and erythropoietin receptor expression in head and neck cancer: relationship to tumor hypoxia. 总被引:7,自引:0,他引:7
Murat O Arcasoy Khalid Amin Shu-Chuan Chou Zishan A Haroon Mahesh Varia James A Raleigh 《Clinical cancer research》2005,11(1):20-27
PURPOSE: Erythropoietin, an oxygen-regulated glycoprotein hormone, is a hematopoietic cytokine that stimulates erythropoiesis by binding to its cellular receptor [erythropoietin receptor (EPOR)]. The recombinant form of human erythropoietin is used to prevent or treat anemia in cancer patients. However, in a recent randomized, placebo-controlled trial involving patients receiving curative radiotherapy for squamous cell carcinoma of the head and neck, erythropoietin treatment was associated with poorer locoregional progression-free survival. The purpose of our study was to determine whether EPOR and its ligand erythropoietin are expressed in primary head and neck cancer. We also investigated the hypothesis that erythropoietin expression in malignant cells may be associated with the presence of tumor hypoxia, an important factor involved in resistance to radiation treatment, tumor aggressiveness, and poor prognosis. EXPERIMENTAL DESIGN: Twenty-one patients received an i.v. infusion of the hypoxia marker pimonidazole hydrochloride before multiple tumor biopsies. Contiguous sections from 74 biopsies were analyzed by immunohistochemistry for EPOR and erythropoietin expression and pimonidazole binding. RESULTS: EPOR expression was present in tumor cells in 97% of the biopsies. Coexpression of erythropoietin was observed in 90% of biopsies. Erythropoietin and pimonidazole adduct staining did not always colocalize within tumors, but there was a significant positive correlation between levels of microregional erythropoietin expression and pimonidazole binding. CONCLUSIONS: The coexpression of erythropoietin and EPOR in tumor cells suggests that erythropoietin may potentially function as an autocrine or paracrine factor in head and neck cancer. The expression of the hypoxia-inducible protein erythropoietin in tumor cells correlates with levels of tumor hypoxia. 相似文献
44.
Jamal M. Arif Mohammed Kunhi Yunus M. Siddiqui Khalid A. El Sayed Khaled Y. Orabi Amal Al-Hazzani Mohammed N. Al-Ahdal Fahad M. Al-Khodairy 《Medicinal chemistry research》2004,13(6-7):553-562
In the present study, two of the probable an umor marine compounds, manzamine A and sarcophine, were screened using benzo[a]pyrene (BP)-derived DNA adduct formation in MCF-7 cells as intermediary biomarker. Briefly, MCF-7 cells were treated with
the compounds for 24 h followed by treatment with BP (0.5 μM). After 24h incubation, cellular DNA was isolated and analyzed
for BP-derived DNA adducts by 32P-postlabeling technique. Manzamine A and sarcophine increased the BP-DNA adducts by 2 to 4-folds. Further, manzamine A (50
μM) substantially down regulated the expression of p53 while sarcophine (50 μM) slightly induced the level of p21. The residual
DNA repair ability was almost completely abolished by manzamine A while sarcophine was ineffective. Based on our preliminary
results, these compounds may be classified as potential genotoxic. 相似文献
45.
Thaer S. Alomar Khalid Mahmood Simon O’Connor Keith Robson Harminder S. Dua 《International ophthalmology》2013,33(5):561-565
Crystalline corneal deposits have been well reported in individual cases of lymphoproliferative disorders associated with hyper-gammaglobulinemia, hence called ‘Crystalline Paraproteinemic Keratopathy’. This is the first report of corneal deposits in a case of localised conjunctival B-cell Lymphoma without paraproteinaemia/hyper-gammaglobulinemia, hence called ‘Presumed Paraproteinic Crystalline Keratopathy’. 相似文献
46.
47.
48.
Association of MICA‐129 polymorphism and circulating soluble MICA level with rheumatoid arthritis in a south Indian Tamil population 下载免费PDF全文
49.
50.