全文获取类型
收费全文 | 28907篇 |
免费 | 3407篇 |
国内免费 | 1940篇 |
专业分类
耳鼻咽喉 | 235篇 |
儿科学 | 346篇 |
妇产科学 | 250篇 |
基础医学 | 2660篇 |
口腔科学 | 620篇 |
临床医学 | 3919篇 |
内科学 | 3316篇 |
皮肤病学 | 358篇 |
神经病学 | 1183篇 |
特种医学 | 1124篇 |
外国民族医学 | 13篇 |
外科学 | 2608篇 |
综合类 | 5886篇 |
现状与发展 | 10篇 |
一般理论 | 3篇 |
预防医学 | 2622篇 |
眼科学 | 747篇 |
药学 | 3631篇 |
37篇 | |
中国医学 | 2784篇 |
肿瘤学 | 1902篇 |
出版年
2024年 | 224篇 |
2023年 | 709篇 |
2022年 | 1708篇 |
2021年 | 2110篇 |
2020年 | 1620篇 |
2019年 | 1113篇 |
2018年 | 1145篇 |
2017年 | 1164篇 |
2016年 | 979篇 |
2015年 | 1475篇 |
2014年 | 1706篇 |
2013年 | 1682篇 |
2012年 | 2426篇 |
2011年 | 2450篇 |
2010年 | 1719篇 |
2009年 | 1349篇 |
2008年 | 1529篇 |
2007年 | 1501篇 |
2006年 | 1369篇 |
2005年 | 1124篇 |
2004年 | 804篇 |
2003年 | 927篇 |
2002年 | 728篇 |
2001年 | 614篇 |
2000年 | 429篇 |
1999年 | 343篇 |
1998年 | 198篇 |
1997年 | 179篇 |
1996年 | 135篇 |
1995年 | 113篇 |
1994年 | 90篇 |
1993年 | 62篇 |
1992年 | 97篇 |
1991年 | 64篇 |
1990年 | 85篇 |
1989年 | 49篇 |
1988年 | 53篇 |
1987年 | 42篇 |
1986年 | 31篇 |
1985年 | 20篇 |
1984年 | 18篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1979年 | 16篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1974年 | 5篇 |
1966年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
随着三维及四维超声技术的迅速发展,时间-空间相关成像技术(STIC)已成为研究胎儿心脏的一种相对成熟的技术,其多种成像模式可提供更多结构及血流的相关信息,为临床诊断提供依据。STIC技术的反转模式可更清晰、准确地呈现心室腔和血管腔的立体结构。本文就其在胎儿心血管系统中的研究进展进行综述。 相似文献
992.
Bo Yang Hang Sun Wei Lin Wugang Hou Hang Li Liying Zhang Fanfan Li Yu Gu Yue Song Qing Li Feng Zhang 《Urologic oncology》2013,31(5):628-634
ObjectiveTo identify the differences of 5-methylcytosine (5-MC) level between primary prostate cancer tissues (PCTs), prostate cancer-adjacent benign tissues (PCABTs), low-grade prostatic intraepithelial neoplasia (LGPIN), and high-grade prostatic intraepithelial neoplasia (HGPIN), and further analysis the 5-MC alterations in prostate cancer with pathologic grade and clinical prognosis.Materials and methodsImmunohistochemistry method with a 5-MC monoclonal antibody was used to identify the 5-methylcytosine (5-MC) levels in PCTs, PCABTs, LGPIN, and HGPIN specimens in the present study. Statistical analysis with SPSS software (SPSS Inc., Chicago, IL) was used to compare differences of 5-MC levels in the four groups and evaluate the 5-MC alterations in prostate cancer with pathologic grade and clinical prognosis.ResultsWe found that 38 of 48 (79.1%) patients studied showed a decrease in 5-MC staining of PCTs compared with PCABTs. The difference in the methylation levels for the PCTs and the PCABTs was highly statistically significant (P < 0.001). Spearman correlation showed there was no statistically significant association between the average score of 5-MC staining and Gleason score sum. Kaplan-Meier survival analysis showed that patient group with no or weak 5-MC staining compared with group with moderate and strong 5-MC staining was associated with better survival of patients, although there was no statistically significant difference between the 2 groups in predicating prognosis (P = 0.385). The average scores of 5-MC staining for LGPIN, HGPIN, PCABTs, and PCTs groups were 6.91, 1.58, 6.63, and 3.10, respectively. The methylation level of HGPIN group, as well as that of PCTs group, was significantly lower than those of LGPIN (P < 0.001; P < 0.001) and PCABTs groups (P < 0.001; P < 0.001), respectively, with the 5-MC levels of PCABTS group similar to that of LGPIN group (P = 0.476). 5-MC levels of HGPIN group was lower than that PCTs group (P = 0.004).ConclusionsWe found that global DNA methylation was low in most prostate cancer compared with benign regions from the same patient's sections. None of the DNA hypomethylation changes in primary cancers were associated with pathologic grade and clinical prognosis. In addition, immunohistochemistry showed that the global methylation was lower in HGPIN compared with LGPIN and methylcytosine staining in HGPIN was lower than that of PCTs. The results suggest that global DNA hypomethylation might play an important role in the process of prostate cancer initiation rather than progression. 相似文献
993.
994.
995.
自从1998年拉米夫定(LAM)被用于治疗慢性乙型肝炎(CHB)以来,核苷(酸)类药物(NAs)的抗病毒作用和重要地位逐步得到认可[1].目前我国大陆上市的NAs除LAM外,还有阿德福韦酯(ADV)、替比夫定(LdT)和恩替卡韦(ETV),这些NAs的广泛使用大大促进了CHB的抗病毒治疗,但是随着临床实践的深入,NAs长期使用导致耐药突变株产生的风险也日益突显.目前临床上HBV对NAs的耐药已成为CHB治疗的一大难点,因此,及时监测NAs相关耐药突变的发生,指导临床合理使用NAs十分必要.本研究采用PCR产物直接测序法分析接受NAs治疗过程中出现病毒学突破的CHB患者体内HBV基因型耐药情况. 相似文献
996.
Qin‐Hong Zhang Zhong‐Ren Sun Jin‐Huan Yue Xue Ren Li‐Bo Qiu Xiao‐Lin Lv Wei Du 《International wound journal》2013,10(2):221-231
To assess the effect of Traditional Chinese Medicine (TCM) [Chinese herbal medicine ointment (CHMO), acupuncture and moxibustion] on pressure ulcer. In this study, we searched MEDLINE, EMBASE, CENTER, CBM, CNKI, WAN FANG and VIP for articles published from database inception up to 4 April 2011. We included randomised controlled trials (RCTs), which compared the effects of TCM with other interventions. We assessed the methodological quality of these trials using Cochrane risk of bias criteria. Ten of 565 potentially relevant trails that enrolled a total of 893 patients met our inclusion criteria. All the included RCTs only used CHMO intervention, because acupuncture and moxibustion trials failed to meet the inclusive criteria. A meta‐analysis showed beneficial effects of CHMO for pressure ulcer compared with other treatments on the total effective rate [risk ratio (RR): 1·28; 95% confidence interval (CI): 1·20–1·36; P = 0·53; I2 = 0%), curative ratio (RR: 2·02; 95% CI: 1·73–2·35; P = 0·11; I2 = 37%) and inefficiency rate (RR: 0·16; 95% CI: 0·02–0·80; P = 0·84; I2 = 0%). However, the funnel plot indicated that there was publication bias in this study. The evidence that CHMO is effective for pressure ulcer is encouraging, but due to several caveats, not conclusive. Therefore, more rigorous studies seem warranted. 相似文献
997.
Jing‐Yu Zhao Jia‐Ke Chai Hui‐Feng Song Jin Zhang Ming‐Huo Xu Yue‐Dan Liang 《International wound journal》2013,10(5):562-572
This study aims to explore the influence of hyaluronic acid (HA) on wound healing during xenogeneic porcine acellular dermal matrix (PADM) composite skin grafting. The results will facilitate the development of methods for improving graft contracture and poor elasticity of composite transplantation. Exogenous HA was added to composite PADM grafts and to thin autologous skin grafts during rabbit full‐thickness skin wound repair. The influence of HA on wound healing was evaluated according to its contracture rate and its expression of collagen types I and III. The possible mechanism was then explored based on HA metabolism and vascularisation in the skin graft. The results show that exogenous HA relieves graft contracture on rabbit wound surfaces, increases collagen I and III expression and decreases the ratio between collagen types. HA stimulates the generation of more CD44 receptors to strengthen its enzymolysis. The resulting metabolites promote the vascularisation of the wound surface, which are conducive for mitigating graft contracture, and further improve the composite grafting effect. 相似文献
998.
999.
Background: Chinese dental technicians play a significant role in the globalised market of dental prosthesis fabrication, but this subject has not been investigated in detail. The demand for dental prostheses increases as individuals pay increasing attention to their oral health. Therefore, it is important to investigate the status of Chinese dental technicians. Objective: To evaluate the current status of Chinese dental technicians. Methods: Dental technicians’ resumés, which reveal information regarding dental technician manpower, degrees, working age and salary, etc., were analysed and compared with those abroad. We also estimated the future demands of dental technician manpower, and discussed some potential solutions. Results: There are fewer dental technicians in China than in other developed countries; they are also of a lower standard. Male technicians outnumber females. The education level of technicians is insufficient, and the education programme is still in its exploratory stage. Conclusions: The development of dental technician teams in China represents both an opportunity and a challenge. It is important to move forward from the current situation to yield long‐term development. This article provides information on the Chinese dental technology industry, identifies the problems and offers solutions for its development. 相似文献
1000.