全文获取类型
收费全文 | 172692篇 |
免费 | 12106篇 |
国内免费 | 763篇 |
专业分类
耳鼻咽喉 | 2066篇 |
儿科学 | 4244篇 |
妇产科学 | 3168篇 |
基础医学 | 21795篇 |
口腔科学 | 3840篇 |
临床医学 | 17176篇 |
内科学 | 35639篇 |
皮肤病学 | 2140篇 |
神经病学 | 15063篇 |
特种医学 | 6606篇 |
外国民族医学 | 1篇 |
外科学 | 28148篇 |
综合类 | 2498篇 |
现状与发展 | 1篇 |
一般理论 | 199篇 |
预防医学 | 15453篇 |
眼科学 | 4089篇 |
药学 | 11934篇 |
2篇 | |
中国医学 | 227篇 |
肿瘤学 | 11272篇 |
出版年
2023年 | 839篇 |
2022年 | 1337篇 |
2021年 | 3246篇 |
2020年 | 1875篇 |
2019年 | 2975篇 |
2018年 | 3657篇 |
2017年 | 2637篇 |
2016年 | 2844篇 |
2015年 | 3438篇 |
2014年 | 5066篇 |
2013年 | 7678篇 |
2012年 | 11193篇 |
2011年 | 11859篇 |
2010年 | 6634篇 |
2009年 | 6102篇 |
2008年 | 10562篇 |
2007年 | 11233篇 |
2006年 | 10795篇 |
2005年 | 11138篇 |
2004年 | 10730篇 |
2003年 | 10035篇 |
2002年 | 9719篇 |
2001年 | 1563篇 |
2000年 | 1277篇 |
1999年 | 1762篇 |
1998年 | 2118篇 |
1997年 | 1694篇 |
1996年 | 1581篇 |
1995年 | 1548篇 |
1994年 | 1301篇 |
1993年 | 1257篇 |
1992年 | 1064篇 |
1991年 | 1064篇 |
1990年 | 922篇 |
1989年 | 885篇 |
1988年 | 909篇 |
1987年 | 909篇 |
1986年 | 914篇 |
1985年 | 1011篇 |
1984年 | 1165篇 |
1983年 | 1122篇 |
1982年 | 1487篇 |
1981年 | 1458篇 |
1980年 | 1255篇 |
1979年 | 783篇 |
1978年 | 856篇 |
1977年 | 794篇 |
1976年 | 700篇 |
1975年 | 617篇 |
1974年 | 594篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Calcified tissue is a common component of atherosclerotic plaques, and occurs most often in mature plaques. The process of calcification is a poorly understood risk factor that may contribute to a plaque's vulnerability to sudden rupture. In this study a solid-state imaging sequence, termed single-point imaging (SPI), was used to observe calcification directly in ex vivo atherosclerotic plaques. Standards were used to validate the ability of (31)P SPI to detect and differentiate calcification from crystalline cholesterol, phospholipids, and other plaque components. After suitable experimental parameters were found, human carotid specimens obtained by endarterectomy were imaged ex vivo by (31)P solid-state imaging and standard (1)H methods. In contrast to (1)H imaging methods, (31)P imaging detected only the calcification in the plaque. 相似文献
72.
Daoyan Wei Henry Q. Xiong James L. Abbruzzese Keping Xie 《Journal of gastrointestinal cancer》2003,33(1):43-60
Pancreatic cancer is a lethal disease characterized by early metastasis, local invasion, and resistance to conventional therapies. To understand its etiology and eventually make prevention of it possible and effective, appropriate carcinogenesis models will certainly help us understand the effects of environmental and genetic elements on pancreatic carcinogenesis. The development of new treatment strategies to control cancer metastasis is of immediate urgency. Fulfillment of this task relies on our knowledge of the cellular and molecular biology of pancreatic cancer metastasis and the availability of biologically and clinically relevant model systems. Many of the existing pancreatic cancer carcinogenesis and metastasis animal models are described in this review. The advantages and disadvantages of each model and their clinical implications are discussed, and special attention is focused on experimental therapeutic strategies targeting pancreatic cancer metastasis. 相似文献
73.
74.
Turboprop: improved PROPELLER imaging. 总被引:1,自引:0,他引:1
A variant of periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) MRI, called turboprop, is introduced. This method employs an oscillating readout gradient during each spin echo of the echo train to collect more lines of data per echo train, which reduces the minimum scan time, motion-related artifact, and specific absorption rate (SAR) while increasing sampling efficiency. It can be applied to conventional fast spin-echo (FSE) imaging; however, this article emphasizes its application in diffusion-weighted imaging (DWI). The method is described and compared with conventional PROPELLER imaging, and clinical images collected with this PROPELLER variant are shown. 相似文献
75.
Mary Ann Richardson Helen M Chao Laura L Read James D Clelland Raymond F Suckow 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2006,(2):195-197
Phenylketonuria (PKU), an inborn error of phenylalanine metabolism, has been shown to be a risk factor for tardive dyskinesia (TD). In male psychiatric patients there was a significant relationship between TD and measures of plasma phenylalanine following ingestion of a standardized phenylalanine dose that was indicative of higher brain availability of phenylalanine in patients with TD. In addition, a medical food formulation consisting of branched chain amino acids, which compete with phenylalanine for transport across the blood-brain barrier, has been demonstrated to be an efficacious treatment for TD. Cumulatively these findings suggested that TD was related to phenylalanine metabolism and thus that sequence variants in the gene for phenylalanine hydroxylase (PAH), the rate-limiting enzyme in the catabolism of phenylalanine, could be associated with TD susceptibility. Genetic screening of PAH in a group of 123 psychiatric patients revealed ten sequence polymorphisms and two mutations, but none appeared to be a significant risk factor for TD. 相似文献
76.
Christine E. East Fung Yee Chan Shaun P. Brennecke James F. King Paul B. Colditz 《分娩》2006,33(2):101-109
Abstract: Background: Fetal pulse oximetry improves the assessment of fetal well‐being during labor. The objective of this study was to evaluate women's satisfaction with their experience with this additional technology. Methods: We surveyed women participating in the FOREMOST trial, a randomized controlled trial comparing the addition of fetal pulse oximetry (FPO) to conventional cardiotocograph (CTG) monitoring (intervention group), versus CTG‐only (control group), in the presence of nonreassuring fetal status during labor. Our survey evaluated 3 aspects of women's experience: labor, fetal monitoring, and participation in the research. The survey was administered within a few days of giving birth and repeated 3 months later. Results: No differences were found between the intervention and control groups for women's evaluations of their labor, fetal monitoring, research, or overall experiences when surveyed on both occasions. Within each study group, a small but statistically significant decline occurred in women's scores for their experience of labor and overall experience from the initial survey close to the time of giving birth, to 3 months later. The magnitude of differences in responses over time was similar for the both groups. Women were more satisfied after a spontaneous or assisted vaginal birth than after cesarean section. Length of time the research midwife was present had a significant positive effect on women's ratings of their experience several days after giving birth (p = 0.006), but no effect at 3 months. Conclusions: The addition of fetal pulse oximetry for the assessment of fetal well‐being during labor did not affect childbearing women's perceptions of fetal monitoring or their labor. Women evaluated their experience in the research process positively overall. Small changes occurred in women's perception of their satisfaction over time. (BIRTH 33:2 June 2006) 相似文献
77.
78.
79.
80.
We report on 4 children who experienced a syncopal episode while being treated with guanfacine without any other evident cause. Syncope appears to be an uncommon side effect of guanfacine and is probably due to drug-induced hypotension or bradycardia. 相似文献