全文获取类型
收费全文 | 159471篇 |
免费 | 33123篇 |
国内免费 | 2442篇 |
专业分类
耳鼻咽喉 | 5246篇 |
儿科学 | 5515篇 |
妇产科学 | 2526篇 |
基础医学 | 4513篇 |
口腔科学 | 1665篇 |
临床医学 | 27630篇 |
内科学 | 49613篇 |
皮肤病学 | 7770篇 |
神经病学 | 15708篇 |
特种医学 | 6898篇 |
外科学 | 42381篇 |
综合类 | 273篇 |
现状与发展 | 72篇 |
一般理论 | 2篇 |
预防医学 | 7455篇 |
眼科学 | 3466篇 |
药学 | 1549篇 |
中国医学 | 25篇 |
肿瘤学 | 12729篇 |
出版年
2024年 | 515篇 |
2023年 | 4823篇 |
2022年 | 1217篇 |
2021年 | 3270篇 |
2020年 | 6162篇 |
2019年 | 2354篇 |
2018年 | 7605篇 |
2017年 | 7524篇 |
2016年 | 8651篇 |
2015年 | 8692篇 |
2014年 | 15858篇 |
2013年 | 16093篇 |
2012年 | 6307篇 |
2011年 | 6281篇 |
2010年 | 10905篇 |
2009年 | 14676篇 |
2008年 | 6529篇 |
2007年 | 4837篇 |
2006年 | 7258篇 |
2005年 | 4528篇 |
2004年 | 3656篇 |
2003年 | 2558篇 |
2002年 | 2660篇 |
2001年 | 3889篇 |
2000年 | 3067篇 |
1999年 | 3314篇 |
1998年 | 3725篇 |
1997年 | 3546篇 |
1996年 | 3410篇 |
1995年 | 3267篇 |
1994年 | 1973篇 |
1993年 | 1614篇 |
1992年 | 1390篇 |
1991年 | 1434篇 |
1990年 | 1073篇 |
1989年 | 1202篇 |
1988年 | 1027篇 |
1987年 | 871篇 |
1986年 | 900篇 |
1985年 | 724篇 |
1984年 | 559篇 |
1983年 | 532篇 |
1982年 | 528篇 |
1981年 | 412篇 |
1980年 | 366篇 |
1979年 | 315篇 |
1978年 | 334篇 |
1977年 | 402篇 |
1975年 | 287篇 |
1972年 | 282篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
91.
Juliette A. Loncaster MD FRCR Ernest Allan 《Photodiagnosis and Photodynamic Therapy》2006,3(2):134-137
Gorlin syndrome (naevoid basal cell carcinoma syndrome) is a genetically linked disorder characterized by the development of multiple basal cell carcinomas (BCCs) throughout life. Cumulative surgery, cryotherapy and other conventional interventions can result in significant disfigurement by middle age. Radiotherapy is contra-indicated because the mutated gene underlying the syndrome, ‘PTCH’, increases sensitivity to ionising radiation, so there is significant likelihood of inducing further tumours in and around the irradiated area. Photodynamic therapy offers a non-invasive treatment option for patients with this condition, with the added advantage of causing minimal scarring. 相似文献
92.
Riemer H J A Slart Ali Agool Dirk J van Veldhuisen Rudi A Dierckx Jeroen J Bax 《Journal of nuclear medicine》2006,47(8):1307-1311
SPECT with 99mTc-labeled agents is better able to detect viability after nitrate administration. Nitrates induce vasodilation and may increase blood flow to severely hypoperfused but viable myocardium, thereby enhancing tracer delivery and improving the detection of viability. Quantitative data on the changes in blood flow are lacking in SPECT but can be provided by PET. The aim of the present study was to use PET to evaluate whether nitrate administration increases blood flow to chronically dysfunctional but viable myocardium. METHODS: 13N-Ammonia PET was used to quantitatively assess blood flow, and 18F-FDG PET was used as the gold standard to detect viable myocardium. Twenty-five patients with chronic ischemic left ventricular dysfunction underwent 13N-ammonia PET at rest and after nitrate administration. RESULTS: A significant increase in nitrate-enhanced blood flow was observed in viable segments (from 0.55 +/- 0.15 to 0.68 +/- 0.24 mL/min/g, P < 0.05). No statistically significant change in blood flow was observed in nonviable segments (0.60 +/- 0.20 vs. 0.55 +/- 0.18 mL/min/g). A ratio of at least 1.1 for nitrate-enhanced flow to resting flow allowed optimal detection of viable myocardium, yielding a sensitivity of 82% with a specificity of 100%. CONCLUSION: 13N-Ammonia PET showed a significant increase in nitrate-enhanced blood flow in viable myocardium, whereas blood flow remained unchanged after nitrate administration in nonviable myocardium. Nitrate use during myocardial perfusion imaging will lead to improved assessment of myocardial viability. 相似文献
93.
94.
95.
Fast CT-PRESS-based spiral chemical shift imaging at 3 Tesla. 总被引:2,自引:0,他引:2
Dirk Mayer Dong-Hyun Kim Elfar Adalsteinsson Daniel M Spielman 《Magnetic resonance in medicine》2006,55(5):974-978
A new sequence is presented that combines constant-time point-resolved spectroscopy (CT-PRESS) with fast spiral chemical shift imaging. It allows the acquisition of multivoxel spectra without line splitting with a minimum total measurement time of less than 5 min for a field of view of 24 cm and a nominal 1.5x1.5-cm2 in-plane resolution. Measurements were performed with 17 CS encoding steps in t1 (Deltat1=12.8 ms) and an average echo time of 151 ms, which was determined by simulating the CT-PRESS experiment for the spin systems of glutamate (Glu) and myo-inositol (mI). Signals from N-acetyl-aspartate, total creatine, choline-containing compounds (Cho), Glu, and mI were detected in a healthy volunteer with no or only minor baseline distortions within 14 min on a 3 T MR scanner. 相似文献
96.
98.
Although psychoanalysis was the first-choice treatment for premature ejaculation (PE) between 1920 and 1960, hardly any reports on its efficacy have been published. Moreover, a scientific debate about its findings has never been fully developed. The recent progress that has been made in the classification of three different PE syndromes creates a new opportunity for psychoanalytic investigations of men with complaints of PE, distinguished by the actual duration of their intravaginal ejaculation latency time (IELT). The term premature-like ejaculatory dysfunction has been introduced to distinguish men with self-perceived PE at normal and long IELT durations from those men with lifelong, acquired and normal variable PE. Psychoanalytic research may contribute to a better understanding of the consequences of objective early ejaculations on the unconscious mental life of men with the four forms of PE. By integrating neurobiological, clinical and epidemiological data of ejaculatory performance, a revival of psychoanalytic research of PE in the four distinct, classified PE groups, will probably contribute to a deeper insight in to the unconscious mental life of men affected by PE. 相似文献
99.
100.
Fibromyalgia is a syndrome of widespread pain, nonrestorative sleep, disturbed mood, and fatigue. Optimal treatment involves
a multidisciplinary approach with a team of health care providers using pharmacologic and nonpharmacologic treatment. Because
of the heterogeneity of the illness, management should be individualized for the patient. Pharmacologic treatment should address
issues of pain control, sleep disturbance, fatigue, and any underlying coexisting mood disorder. Nonpharmacologic treatment
should include patient education, a regular exercise and stretching program, and cognitive behavioral therapy. All of these
are essential to improving functional capacity and quality of life. This review provides general guidelines in initiating
a successful pharmacologic treatment program for patients with fibromyalgia. 相似文献