全文获取类型
收费全文 | 6399篇 |
免费 | 340篇 |
国内免费 | 49篇 |
专业分类
耳鼻咽喉 | 54篇 |
儿科学 | 123篇 |
妇产科学 | 28篇 |
基础医学 | 789篇 |
口腔科学 | 146篇 |
临床医学 | 387篇 |
内科学 | 1737篇 |
皮肤病学 | 229篇 |
神经病学 | 429篇 |
特种医学 | 293篇 |
外科学 | 1039篇 |
综合类 | 39篇 |
预防医学 | 144篇 |
眼科学 | 158篇 |
药学 | 432篇 |
中国医学 | 7篇 |
肿瘤学 | 754篇 |
出版年
2024年 | 9篇 |
2023年 | 75篇 |
2022年 | 173篇 |
2021年 | 252篇 |
2020年 | 106篇 |
2019年 | 160篇 |
2018年 | 216篇 |
2017年 | 175篇 |
2016年 | 213篇 |
2015年 | 195篇 |
2014年 | 231篇 |
2013年 | 274篇 |
2012年 | 437篇 |
2011年 | 523篇 |
2010年 | 254篇 |
2009年 | 227篇 |
2008年 | 404篇 |
2007年 | 401篇 |
2006年 | 388篇 |
2005年 | 372篇 |
2004年 | 349篇 |
2003年 | 312篇 |
2002年 | 328篇 |
2001年 | 92篇 |
2000年 | 63篇 |
1999年 | 64篇 |
1998年 | 54篇 |
1997年 | 47篇 |
1996年 | 48篇 |
1995年 | 24篇 |
1994年 | 24篇 |
1993年 | 21篇 |
1992年 | 26篇 |
1991年 | 27篇 |
1990年 | 21篇 |
1989年 | 28篇 |
1988年 | 31篇 |
1987年 | 24篇 |
1986年 | 17篇 |
1985年 | 19篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 10篇 |
1977年 | 5篇 |
1970年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有6788条查询结果,搜索用时 0 毫秒
61.
Tomohiro Kaneta Nobuyuki Okamura Akira Arai Kentaro Takanami Katsutoshi Furukawa Manabu Tashiro Shozo Furumoto Ren Iwata Shoki Takahashi Hiroyuki Arai Kazuhiko Yanai Yukitsuka Kudo 《Japanese journal of radiology》2014,32(3):138-144
Purpose
To examine the usefulness of the early phase [11C]BF-227 positron emission tomography (PET) for (1) conferring additional diagnostic value by providing perfusion-like information and (2) obtaining the appropriate anatomical standardization (AS) using three-dimensional stereotactic surface projection (3D-SSP) method.Methods
This study included 20 mild cognitive impairment (MCI), 19 Alzheimer’s disease (AD), and 17 normal cognitive (NC) subjects. Early- and late-phase BF-227 PET images were obtained 0–10 and 40–60 min after the injection, respectively. AS for late-phase BF-227 images were performed by 2 methods: (1) method A, for AS of late-phase BF-227 images using 8F-fluorodeoxyglucose (FDG) images of the same subject and (2) method B, for AS of late-phase BF-227 images using early phase BF-227 images.Results
Method B was successfully used for AS in all cases. The Z score maps of 3D-SSP analyses of FDG PET and early phase BF-227 PET for AD and MCI groups showed a typical AD-like pattern. Regional analyses revealed that the early phase BF-227 PET showed significant differences between AD and NC, and MCI and NC.Conclusion
The early phase BF-227 PET images showed significant abnormal findings for the AD and MCI groups. AS of late-phase BF-227 images using early phase BF-227 images were successful, and enabled appropriate 3D-SSP analyses. 相似文献62.
Tomohiro Yoneyama Ukihide Tateishi Takashi Terauchi Tomio Inoue 《Japanese journal of radiology》2014,32(3):155-163
Purpose
This study was conducted to assess the relationship between 11C-choline uptake and pathologic findings obtained by combined use of magnetic resonance (MR) and positron emission tomography (PET) imaging of patients with prostate cancer.Materials and methods
We retrospectively evaluated 69 patients with prostate cancer who underwent 11C-choline PET-CT and magnetic resonance imaging before radical prostatectomy. Combined MR–PET images were acquired to obtain precise anatomic information. The maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) were compared with pathologic findings from resected specimens as the reference standard.Results
The mean and standard deviation of tumor SUVmax and MTV were 3.9 ± 1.8 and 12.9 ± 16.4, respectively. Tumors with high MTV (≧8.2) were more likely to be admixed with prostatic intraepithelial neoplasia (PIN) (p < 0.0001) or hyperplasia (p < 0.0001) in the background than those without these findings. Multiple regression analysis also revealed that the presence of hyperplasia (OR; 4.25, 95 % CI 1.25–14.4, p = 0.02) and PIN (OR; 9.22, 95 % CI 2.60–32.7, p = 0.001) were associated with tumors with high MTV.Conclusion
We have demonstrated, by pathologic evaluation of patients with prostate cancer, that 11C-choline uptake volume is greater for prostate cancer admixed with PIN and hyperplasia than that without. 相似文献63.
Risk of hip fractures in stroke patients is higher than that in a reference population. Hyperhomocysteinemia is regarded as a risk factor for ischemic stroke. The high prevalence of osteoporosis among patients with homocystinuria suggests that hyperhomocysteine may also increase the risk of fractures. To determine the association between homocysteine concentration and the risk of hip fractures, we studied a cohort of stroke patients with hemiplegia. Age-adjusted incidence rates of a hip fracture were calculated for quartiles of homocysteine concentrations. Cox proportional-hazard regression was used to calculate hazard ratios for quartiles of homocysteine levels. The initial enrolment of 433 hemiplegic patients with ischemic stroke, older than 65 years old, were followed for up to 10 years. The mean plasma homocysteine concentration at the enrolment was 14.1 +/- 5.2 micromol/L. There were 33 hip fractures among men and 46 among women during the mean follow-up period of 9.0 years. The age-adjusted incidence rates per 1000 person-years for hip fractures increased almost linearly from 2.89 in the lowest to 27.87 in the highest quartiles of homocysteine levels. We conclude that hyperhomocysteinemia is one of the risk factors for hip fractures in stroke patients. 相似文献
64.
Tomohiro Inoue Kazuhiro Ohwaki Akira Tamura Kazuo Tsutsumi Isamu Saito Nobuhito Saito 《Neurosurgical review》2016,39(4):633-641
Clinical results as well as cognitive performances after extracranial to intracranial (EC-IC) bypass in conjunction with contralateral carotid endarterectomy (CEA) are poorly understood. Data from 14 patients who underwent unilateral EC-IC bypass for atherosclerotic internal carotid artery (ICA)/middle cerebral artery (MCA) steno-occlusive disease in conjunction with CEA for contralateral cervical carotid stenosis were retrospectively reviewed. Postoperative results were evaluated by MRI imagings. Nine patients also underwent neuropsychological examinations (NPEs), including assessment by the Wechsler Adult Intelligence Scale-Third Edition and the Wechsler Memory Scale-Revised (WMS-R) before and about 6 months after bilateral surgeries. Postoperative MRI follow-up (median, 8 months; interquartile range, 7–8 months) confirmed successful bypass in all patients, with no additional ischemic lesions on T2WI when compared with preoperative imaging. Further, MRA showed patent bypass and contralateral smooth patency at CEA portion in all patients. In the group rate analysis, all five postoperative NPE scores (Verbal IQ, Performance IQ, WMS-memory, WMS-attention, and Average scores of all those four scores) were improved relative to preoperative NPE scores. Performance IQ and Average score improvements were statistically significant. Clinical results after EC-IC bypass in conjunction with contralateral CEA were feasible. Based on the group rate analysis, we conclude that successful unilateral EC-IC bypass and contralateral carotid endarterectomy does not adversely affect postoperative cognitive function. 相似文献
65.
Min-Ho Song Tomohiro Nakayama Keisuke Hattori Shigeru Miyachi 《General thoracic and cardiovascular surgery》2009,57(1):40-42
Effort angina of a 70-year-old man was diagnosed as due to triple coronary vessel disease, and he was scheduled to undergo
coronary artery bypass surgery. Preoperative carotid duplex scan revealed more than 75% stenosis of the right internal carotid
artery, which was functionally proven to be significantly ischemic on brain single photon emission computed tomography. Although
he was neurologically asymptomatic, we chose staged surgery for fear of stroke during coronary artery bypass surgery. He had
successful carotid artery stenting first by neurosurgeons; then, 2 months later he underwent uneventful coronary artery bypass
surgery. This experience prompted us to report the case. 相似文献
66.
Nui A Hirama T Katsuramaki T Maeda T Meguro M Nagayama M Matsuno T Mizumoto T Hirata K 《Journal of pediatric surgery》2005,40(9):e9-11
It has been reported that ingested magnets can cause intestinal fistula formation or perforation, leading to intestinal obstruction. However, there are no previous case reports that magnet ingestion additionally caused an intestinal volvulus. We report herein the case of a 1-year-old boy in whom the ingested magnets caused a volvulus of part of the small intestine leading to the resection of the necrotic portion. We think that if more than one magnet is found as a foreign body in the intestine, they should be removed immediately by laparotomy. Clinicians who care for children should be aware of this unexpected risk. 相似文献
67.
A wide range of physiological effects are mediated by alpha2-adrenoceptors (ARs) through their association with G protein-coupled inwardly rectifying potassium (GIRK) channels. Although alpha2-ARs are divided into three subtypes (alpha2A-C), a pharmacological distinction among the subtypes is difficult to establish because of the lack of a selective agonist and antagonist; therefore, little is known about the effects of anesthetics on the alpha2-AR subtypes. We expressed each subtype together with GIRK1/GIRK2 subunits in Xenopus oocytes and observed alpha2-AR-mediated GIRK1/GIRK2 currents to test the effects of ethanol, halothane, and several IV anesthetics at clinical concentrations. UK 14,304, a selective alpha2-AR agonist, evoked GIRK1/GIRK2 currents in every subtype. None of the IV anesthetics, which included pentobarbital, propofol, ketamine, and alphaxalone, influenced UK 14,304-evoked potassium currents in any of the receptor subtypes. Ethanol enhanced the UK 14,304-evoked potassium currents, whereas halothane inhibited the currents. However, these effects were not significantly different from those on the baseline-GIRK1/GIRK2 current, suggesting that neither ethanol nor halothane acts directly on the alpha2-AR subtypes. Although none of the drugs examined had any effect on the alpha2-ARs, the physiological actions of the alpha2-ARs mediated by the GIRK1/GIRK2 channels may be affected by ethanol and halothane. 相似文献
68.
Ohno T Ogata K Aiba S Fukuchi M Osawa H Mogi A Motegi M Nagashima K Ishizaki M Mochiki E Kuwano H 《Surgery today》2005,35(6):493-495
We report a case of idiopathic omental bleeding in a 27-year-old man who was brought to our hospital after the sudden development of intermittent abdominal pain, nausea, and fainting. Computed tomography showed intra-abdominal fluid and emergency laparotomy revealed a hemorrhagic mass in the omental bursa, which was excised. The patient was successfully treated and a diagnosis of idiopathic omental bleeding was made. 相似文献
69.
Takuro Yoshikawa Yasuyuki Suzuki Yasuhiro Fujino Keitaro Kakinoki Shiri Li Tadahiro Goto Tomohiro Tanaka Ippei Matsumoto Tetsuya Sakai Yasuki Tanioka Hiroshi Yokozaki Yoshikazu Kuroda 《American journal of transplantation》2005,5(9):2135-2142
Small bowel transplantation (SBT) is associated with a high incidence of infectious complications because of ischemia/reperfusion (I/R) mucosal injury concomitant with potent immunosuppression. In this study, we evaluated whether the cavitary two-layer method (cTLM) could reduce I/R injury and allow early mucosal restoration, particularly after prolonged preservation and transplantation. Canine heterotopic segmental SBT was performed immediately without preservation (group 1), after 24-h preservation in UW solution (group 2) or by the cTLM (group 3). The graft samples were taken 1 h after reperfusion and on days 1, 4 and 7. We assessed graft mucosa with detailed microscopic and electromicroscopic analyses. In Group 3, histological injury and cell apoptosis after transplantation were significantly alleviated and rapidly recovered to a similar level of group 1. The mucosal restoration was morphologically completed within 4 days. In contrast, in group 2, more pronounced mucosal injury and delayed recovery were noted. Crypt cell proliferation activity was well maintained in groups 1 and 3 throughout the experimental period. Our ultrastructural analysis suggested that mitochondrial integrity achieved by the cTLM was a basal mechanism under the prompt mucosal restoration. The cTLM could reduce I/R injury, facilitate mucosal regeneration and restore the nearly normal structure early after SBT. 相似文献
70.
Hashimura T Shirahase T Inoue T Yamasaki T Terada N Ogura K Arai Y Hida S Ueda T 《Hinyokika kiyo. Acta urologica Japonica》2005,51(7):439-442
A prospective randomized study was conducted to evaluate the efficacy of prophylactic intravesical instillation of pirarubicin (THP) prior to transurethral resection (TUR) of superficial bladder cancer. A total of 63 patients were randomized into two groups, the THP group and the control group. In the THP group, 30 mg of THP dissolved in 50 ml saline was administered 4 times intravesically for 4 consecutive days before TUR. In the control group, no instillation was performed before TUR. The patients were followed by cystoscopy and urinary cytology every 3 months. The non-recurrence rates in the THP group and control group were 54.1% versus 37.6% at 1 year and 40.4% versus 26.8% at 2 years, respectively (P = 0.086). Time to recurrence for tumors larger than 1 cm was significantly longer in the THP group (P = 0.0137). Time to recurrence for single and grade 1+2 tumors tended to be longer in the THP group (P = 0.09, P = 0.079). No significant adverse effects were observed in any patient. Our findings suggest that intravesical THP instillation prior to TUR would be effective for patients with single, low grade lesions larger than 1 cm of superficial bladder cancer. 相似文献