全文获取类型
收费全文 | 5514篇 |
免费 | 486篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 82篇 |
儿科学 | 124篇 |
妇产科学 | 72篇 |
基础医学 | 760篇 |
口腔科学 | 97篇 |
临床医学 | 503篇 |
内科学 | 1241篇 |
皮肤病学 | 57篇 |
神经病学 | 521篇 |
特种医学 | 278篇 |
外科学 | 1014篇 |
综合类 | 75篇 |
一般理论 | 2篇 |
预防医学 | 433篇 |
眼科学 | 155篇 |
药学 | 290篇 |
中国医学 | 1篇 |
肿瘤学 | 308篇 |
出版年
2021年 | 69篇 |
2020年 | 54篇 |
2019年 | 52篇 |
2018年 | 88篇 |
2017年 | 74篇 |
2016年 | 58篇 |
2015年 | 97篇 |
2014年 | 119篇 |
2013年 | 184篇 |
2012年 | 262篇 |
2011年 | 292篇 |
2010年 | 171篇 |
2009年 | 155篇 |
2008年 | 232篇 |
2007年 | 256篇 |
2006年 | 281篇 |
2005年 | 266篇 |
2004年 | 246篇 |
2003年 | 208篇 |
2002年 | 197篇 |
2001年 | 150篇 |
2000年 | 164篇 |
1999年 | 101篇 |
1998年 | 76篇 |
1997年 | 57篇 |
1996年 | 64篇 |
1995年 | 55篇 |
1994年 | 52篇 |
1993年 | 47篇 |
1992年 | 85篇 |
1991年 | 108篇 |
1990年 | 88篇 |
1989年 | 89篇 |
1988年 | 86篇 |
1987年 | 77篇 |
1986年 | 59篇 |
1985年 | 64篇 |
1984年 | 79篇 |
1983年 | 53篇 |
1982年 | 54篇 |
1981年 | 51篇 |
1980年 | 49篇 |
1979年 | 62篇 |
1978年 | 60篇 |
1977年 | 59篇 |
1976年 | 49篇 |
1975年 | 47篇 |
1974年 | 48篇 |
1973年 | 47篇 |
1969年 | 41篇 |
排序方式: 共有6013条查询结果,搜索用时 46 毫秒
1.
2.
This work describes the synthesis and tumor affinity testing of 8-[123I]iodo-l-1,2,3,4-tetrahydro-7-hydroxyisoquinoline-3-carboxylic acid [ITIC(OH)], a cyclic non-naturally occurring amino acid as an imaging probe for prostate cancer. Parameters for labelling were optimized with regard to the amount of precursor, the temperature and time. Thereafter, ITIC(OH) was evaluated in terms of its uptake in primary human PC-3 and DU-145 prostate cancer cells, followed by analysis of the underlying mechanisms of the radioactivity accumulation in tumor cells. No-carrier-added ITIC(OH) was obtained in 80+/-15% radiochemical yield and >98% radiochemical purity by a one-step radioiodination, using IODO-GEN as oxidant. The total synthesis time was less than 30 min, and compatible with a clinical routine production. ITIC(OH) accumulated intensively in primary human prostate cancer cells. The radioactivity incorporation in tumor following a 10-min incubation at 37 degrees C/pH 7.4 varied from 35% to 58% of the total loaded activity per 10(6) tumor cells (355-540 cpm/1000 cells). Inhibition experiments revealed that ITIC(OH) was taken up into tumor by an active transport different from the common amino acid carrier systems, including the sodium-dependent system A and B+,0, and the sodium-independent L- and ASC-type transporter. In contrast, the cellular incorporation was dependent on the membrane potential and correlated with the activity of the mitochondria. In conclusion, the specific and high-level accumulation of ITIC(OH) in human prostate carcinoma cells, indicates that the new radiopharmaceutical is a good candidate for further in vivo investigations to ascertain its potential as an imaging probe for prostate cancer by SPET. 相似文献
3.
D B Irving J L Cook H B Menz 《Journal of Science and Medicine in Sport》2006,9(1-2):11-22; discussion 23-4
4.
Thomas Benner Andr J.W. van der Kouwe John E. Kirsch A. Gregory Sorensen 《Magnetic resonance in medicine》2006,56(1):204-209
Although the magnetic field of an MR scanner is very stable under little or no load, it can become less stable under heavy‐duty cycle conditions, such as in diffusion tensor imaging (DTI). Uncorrected, such field drifts lead to an apparent image shift along the phase‐encoding direction and decreasing effectiveness of fat saturation pulses. A method is presented to adjust the center frequency of all RF pulses and the receiver in real time during the acquisition. No data postprocessing or changes to the sequence timing are necessary. In vivo acquisitions were performed to assess the prolonged effectiveness of fat saturation. Field drifts of approximately 2.5 Hz/min were measured and corrected during DTI acquisitions at b‐values of up to 3000 s/mm2. The effectiveness of fat saturation diminished over the duration of an 18‐min acquisition when the drift was left uncorrected. The proposed method corrects for apparent image shift and ensures continuously effective fat saturation over the duration of an acquisition. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc. 相似文献
5.
6.
7.
Background
Chronic plantar heel pain (CPHP) is one of the most common musculoskeletal disorders of the foot, yet its aetiology is poorly understood. The purpose of this study was to examine the association between CPHP and a number of commonly hypothesised causative factors. 相似文献8.
9.
Nena W. Chin M.D. Ph.D. Irving Chapman M.D. 《The American journal of gastroenterology》1988,83(6):667-669
Extensive search of the literature reveals the extreme rarity of true diverticulum of the gallbladder. Its frequency varies from 0.0008% of all resected gallbladders at the Mayo Clinic to 0.06% of a series of congenital anomalies of the gallbladder collected from the world literature. We are presenting a case of a true diverticulum of the gallbladder with sonographic demonstration and focal malignant alterations, neither one of which has been reported previously. The difference between true and false diverticula of the gallbladder is discussed. 相似文献
10.
Miriam Stewart Linda Reutter Edward Makwarimba Irving Rootman Deanna Williamson Kim Raine Doug Wilson Janet Fast Rhonda Love Sharon McFall Deana Shorten Nicole Letourneau Karen Hayward Jeff Masuda William Rutakumwa 《Revue canadienne de recherche en sciences infirmières》2005,37(3):104-131
Poverty influences health status, life expectancy, health behaviours, and use of health services. This study examined factors influencing the use of health-related services by people living in poverty. In the first phase, 199 impoverished users of health-related services in 2 large Canadian cities were interviewed by their peers. In the second phase, group interviews with people living in poverty (n = 52) were conducted. Data were analyzed using thematic content analysis. Diverse health-related services were used to meet basic and health needs, to maintain human contact, and to cope with life's challenges. Use of services depended on proximity, affordability, convenience, information, and providers' attitudes and behaviours. Use was impeded by inequities based on income status. To promote the health of people living in poverty, nurses and other health professionals can enhance the accessibility and quality of services, improve their interactions with people living in poverty, provide information about available programs, offer coordinated community-based services, collaborate with other sectors, and advocate for more equitable services and policies. 相似文献