全文获取类型
收费全文 | 9246篇 |
免费 | 628篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 170篇 |
儿科学 | 257篇 |
妇产科学 | 190篇 |
基础医学 | 1042篇 |
口腔科学 | 197篇 |
临床医学 | 1100篇 |
内科学 | 1707篇 |
皮肤病学 | 129篇 |
神经病学 | 780篇 |
特种医学 | 241篇 |
外国民族医学 | 2篇 |
外科学 | 1415篇 |
综合类 | 163篇 |
一般理论 | 12篇 |
预防医学 | 1043篇 |
眼科学 | 257篇 |
药学 | 669篇 |
中国医学 | 24篇 |
肿瘤学 | 499篇 |
出版年
2023年 | 52篇 |
2022年 | 102篇 |
2021年 | 227篇 |
2020年 | 135篇 |
2019年 | 174篇 |
2018年 | 195篇 |
2017年 | 148篇 |
2016年 | 169篇 |
2015年 | 218篇 |
2014年 | 315篇 |
2013年 | 411篇 |
2012年 | 561篇 |
2011年 | 530篇 |
2010年 | 294篇 |
2009年 | 267篇 |
2008年 | 475篇 |
2007年 | 450篇 |
2006年 | 402篇 |
2005年 | 437篇 |
2004年 | 360篇 |
2003年 | 341篇 |
2002年 | 326篇 |
2001年 | 230篇 |
2000年 | 249篇 |
1999年 | 235篇 |
1998年 | 87篇 |
1997年 | 74篇 |
1996年 | 66篇 |
1995年 | 67篇 |
1994年 | 64篇 |
1993年 | 50篇 |
1992年 | 143篇 |
1991年 | 131篇 |
1990年 | 156篇 |
1989年 | 106篇 |
1988年 | 118篇 |
1987年 | 116篇 |
1986年 | 102篇 |
1985年 | 109篇 |
1984年 | 84篇 |
1983年 | 75篇 |
1982年 | 64篇 |
1979年 | 80篇 |
1978年 | 67篇 |
1975年 | 54篇 |
1974年 | 48篇 |
1973年 | 65篇 |
1972年 | 56篇 |
1971年 | 53篇 |
1969年 | 58篇 |
排序方式: 共有9897条查询结果,搜索用时 15 毫秒
31.
What is the prognostic value of myocardial perfusion imaging using rubidium-82 positron emission tomography? 总被引:5,自引:0,他引:5
Keiichiro Yoshinaga Benjamin J W Chow Kathryn Williams Li Chen Robert A deKemp Linda Garrard Alexander Lok-Tin Szeto May Aung Ross A Davies Terrence D Ruddy Rob S B Beanlands 《Journal of the American College of Cardiology》2006,48(5):1029-1039
OBJECTIVES: The objective was to determine the prognostic value of rubidium-82 (82Rb) positron emission tomography (PET) myocardial perfusion imaging (MPI). BACKGROUND: 82Rb PET MPI accurately diagnoses coronary artery disease (CAD). However, there are limited data evaluating its prognostic value. METHODS: Follow-up (3.1 +/- 0.9 years) was obtained in 367 patients who underwent dipyridamole 82Rb PET MPI. Patients were divided into groups based on their summed stress score (SSS): group I, normal (<4); group II, mild (4 to 7); and group III, moderate (8 to 11) to severe (> or =12). RESULTS: There were significant differences among patients in the 3 SSS groups for hard events (cardiac death and myocardial infarction [MI]) (p < 0.001) and total cardiac events (hard events, revascularization and hospitalization) (p < 0.001). The annual hard events rates were 0.4%, 2.3%, and 7.0% in the normal, mild, and moderate-severe groups, respectively. In adjusted survival models, 82Rb PET SSS was the strongest predictor of total cardiac events and a significant predictor of hard events. Among patients referred for PET after 99mTc single-photon emission computed tomography, the annual total event rate was higher with abnormal versus normal SSS on PET (15.2% vs. 1.3%, p < 0.001). In patients with obesity, the annual total event rate was 11.1% with an abnormal scan and 1.5% with a normal scan (p < 0.001). CONCLUSIONS: This study shows that 82Rb PET MPI has significant prognostic value for predicting cardiac events, including death and MI. It also seems to have prognostic value in patients whose diagnosis remains uncertain after single-photon emission computed tomography MPI and in obese patients. The prognostic value of PET MPI may improve the management of cardiac patients. 相似文献
32.
Dr. Bektaş Açikgöz Mehmet Turgut Osman Ekin Özcan Tunçalp Özgen Beyhan Demirhan Şevket Ruacan 《Lasers in medical science》1992,7(1-4):49-53
In this study we have investigated the negative influence of CO2 and Nd-YAG laser irradiation on rapid cranial regeneration and whether it has any use in certain types of craniosynostosis.
Twenty-two newborn rats were used in the study. Both CO2 and Nd-YAG laser irradiation, which was applied to free bony edges after, suturectomies, resulted in a significant decrease
in skull regeneration. Histopathological examinations revealed severe degeneration caused by both types of laser energies. 相似文献
33.
Protein concentration and acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were assayed in the cerebrospinal fluid (CSF) of 26 healthy normal subjects (20-86 years old), 27 patients with dementia of the Alzheimer type (DAT), and 10 patients with dementia of the Alzheimer type with extrapyramidal signs (EDAT). In normal subjects, there was an age-related increase in CSF protein and AChE activity and a significant correlation (p less than 0.001) between CSF protein and BChE activity. In the DAT and EDAT groups, CSF AChE activities (mean +/- SD = 17.5 +/- 3.6 and 15.3 +/- 4.4 nmol/min/ml, respectively) were significantly lower (p less than 0.05) than in 13 age-matched control subjects (21.5 +/- 5.6 nmol/min/ml). In contrast, neither CSF protein concentration, BChE activity, nor the ratio of AChE/BChE differed significantly between groups. In patients with DAT, CSF AChE activity was significantly lower (p less than 0.05) in subjects with an early onset compared to those with a late onset (16.4 +/- 3.4 and 19.7 +/- 2.8 nmol/min/ml, respectively), and activity in the latter group did not differ significantly from control values. CSF AChE activity was not related to dementia severity and did not change significantly over an 18-month period. Although these results confirm a cholinergic deficit in patients with DAT, the considerable overlap of CSF AChE activity between groups and the nonsignificant correlation between AChE activity and dementia severity limit the usefulness of CSF AChE as a diagnostic marker of this disorder. 相似文献
34.
彭暾 《中医杂志(英文版)》2006,26(2):113-114
In treating Meniere's disease, author has found that the compatible use of heavy dosage of Gu Sui Bu (骨碎补 Rhizoma Drynariae) can produce very good effect for relieving dizziness, vertigo and tinnitus. Some of the sample cases are cited in the following. 相似文献
35.
Tun Hing Lui 《Knee surgery, sports traumatology, arthroscopy》2007,15(5):671-675
We describe an arthroscopic approach of tarsometatarsal arthrodesis for post-traumatic arthritis. Five tarsometatarsal portals
(medial, P1–2, P2–3, P3–4, P4–5) are identified at the junctional points between the metatarsals by means of image intensifier.
The first metatarsocuneiform joint is approached through the medial and P1–2 portal. Articular cartilage is denuded and micro-fracture
of subchondral bone is performed with an arthroscopic awl. The second metatarsocuneiform joint is approached through the P1–2
and P2–3 portals and the third metatarsocuneiform joint is approached through the P2–3 and P3–4 portals. The articular surfaces
are prepared for arthrodesis. The articulations are kept in desired position and transfixed with 4.0 mm cannulated screws.
The fourth and fifth metatarsocuboid articulations are rarely included in the procedure. Arthroscopic arthrodesis or tendon
arthroplasty of the lateral column can be performed through the P3–4 and P4–5 portals. 相似文献
36.
Orbital trauma may be associated with various visual and ocular motility disturbances. We describe a case of orbital apex syndrome after penetrating orbital trauma. 相似文献
37.
38.
Keith May 《American journal of obstetrics and gynecology》1991,165(6):2000-2002
39.
T May 《European journal of pharmacology》1992,215(2-3):313-316
Experiments were carried out with brain tissues of ethanol-experienced (long-term ethanol intake but withdrawn) vs. ethanol-naive animals. The in vitro 3H antagonist binding of [3H]SCH 23390 and of [3H]spiperone to striatal dopamine D1- and D2-like receptors revealed no significant changes in KD and Bmax values. Displacement of the 3H antagonist binding by dopamine indicated high- and low-affinity states, which also showed no significant alteration at the D2-like receptor but a 5-fold increase of dopamine affinity at the high-affinity state of the D1-like receptor of the ethanol-experienced rats. 相似文献
40.
Twenty new cases of Silo filler's disease (SFD) have been collected, documenting the incidence and clinical features of exposure to nitrogen oxides present in freshly filled silos. Cases of SFD were identified using a statewide computerized discharge diagnosis system. Fifteen of these were identified in the index period, allowing us to calculate an approximate annual incidence of 5.0 cases/100,000 silo-associated farm workers/yr in New York State. All cases occurred during harvest periods, with 80% in September and October. Corn silage was the gas source in 18 (90%). All cases involved young white men (mean age, 31.5 yr). The most common presenting feature was dyspnea. All victims entered a silo during the peak danger period, and only one used recommended ventilation techniques. Four cases ended in death (20% mortality). Silo filler's disease, although rare, is a potentially devastating disease involving otherwise young, healthy farm workers. It is readily prevented. 相似文献