全文获取类型
收费全文 | 1427719篇 |
免费 | 126095篇 |
国内免费 | 5203篇 |
专业分类
耳鼻咽喉 | 18910篇 |
儿科学 | 46021篇 |
妇产科学 | 38616篇 |
基础医学 | 200956篇 |
口腔科学 | 40612篇 |
临床医学 | 154036篇 |
内科学 | 280125篇 |
皮肤病学 | 29529篇 |
神经病学 | 123218篇 |
特种医学 | 51489篇 |
外国民族医学 | 366篇 |
外科学 | 200569篇 |
综合类 | 29037篇 |
现状与发展 | 41篇 |
一般理论 | 485篇 |
预防医学 | 126946篇 |
眼科学 | 30979篇 |
药学 | 100299篇 |
6篇 | |
中国医学 | 3201篇 |
肿瘤学 | 83576篇 |
出版年
2021年 | 13277篇 |
2020年 | 11496篇 |
2019年 | 13441篇 |
2018年 | 22437篇 |
2017年 | 18841篇 |
2016年 | 20214篇 |
2015年 | 22202篇 |
2014年 | 30120篇 |
2013年 | 42853篇 |
2012年 | 47897篇 |
2011年 | 50340篇 |
2010年 | 33290篇 |
2009年 | 33186篇 |
2008年 | 46151篇 |
2007年 | 47672篇 |
2006年 | 48695篇 |
2005年 | 45951篇 |
2004年 | 43318篇 |
2003年 | 40968篇 |
2002年 | 39624篇 |
2001年 | 62559篇 |
2000年 | 63594篇 |
1999年 | 53848篇 |
1998年 | 16496篇 |
1997年 | 15015篇 |
1996年 | 14912篇 |
1995年 | 13996篇 |
1994年 | 12609篇 |
1993年 | 11786篇 |
1992年 | 42284篇 |
1991年 | 41387篇 |
1990年 | 39947篇 |
1989年 | 37851篇 |
1988年 | 35063篇 |
1987年 | 34066篇 |
1986年 | 32496篇 |
1985年 | 30965篇 |
1984年 | 23309篇 |
1983年 | 19887篇 |
1982年 | 12002篇 |
1979年 | 20902篇 |
1978年 | 14978篇 |
1977年 | 12220篇 |
1976年 | 11984篇 |
1975年 | 12199篇 |
1974年 | 14889篇 |
1973年 | 14545篇 |
1972年 | 13442篇 |
1971年 | 12481篇 |
1970年 | 11556篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
Randomized trial of bilateral oophorectomy versus tamoxifen in premenopausal women with metastatic breast cancer 总被引:2,自引:0,他引:2
J N Ingle J E Krook S J Green T P Kubista L K Everson D L Ahmann M N Chang H F Bisel H E Windschitl D I Twito 《Journal of clinical oncology》1986,4(2):178-185
A randomized clinical trial was performed to compare the efficacy of bilateral oophorectomy with that of tamoxifen at a dose of 10 mg twice daily in premenopausal women with metastatic breast cancer, and to examine the efficacy of each as a crossover treatment. Initial treatment responses were seen in ten of 27 patients (37%) treated with oophorectomy and seven of 26 patients (27%) treated with tamoxifen. The difference was not statistically significant. Crossover responses were seen in five of 15 patients (33%) treated with oophorectomy, including three responses in ten prior tamoxifen nonresponders; and two of 18 patients (11%) treated with tamoxifen. Time to progression distributions were not significantly different during initial treatment, and no significant differences in survival were noted. Thus, there was no overall disadvantage to the use of tamoxifen as opposed to oophorectomy as initial hormonal therapy, and a failure to respond to tamoxifen did not preclude a response to subsequent oophorectomy. Exploratory data analysis within subsets indicated consistent differential treatment effects in the visceral dominant patients. Of the 16 such patients treated with oophorectomy, eight (50%) experienced objective responses but there were no responses in the 14 patients treated with tamoxifen. In the nine visceral dominant crossover patients who had not responded to initial tamoxifen, three (33%) subsequently responded to oophorectomy. Time to progression distributions within the visceral dominant subset appeared to be better for the patients treated initially with oophorectomy. However, one must be very cautious in drawing conclusions from exploratory subset analyses, especially with the small sample size. Further studies would be required to test any hypothesis of differential organ site responsiveness. 相似文献
993.
994.
995.
Davangere P Devanand Christian G Habeck Matthias H Tabert Nikolaos Scarmeas Gregory H Pelton James R Moeller Brett D Mensh Tyler Tarabula Ronald L Van Heertum Yaakov Stern 《Neuropsychopharmacology》2006,31(6):1327-1334
Temporoparietal and posterior cingulate metabolism deficits characterize patients with Alzheimer's disease (AD). A H(2)(15)O resting PET scan covariance pattern, derived by using multivariate techniques, was previously shown to discriminate 17 mild AD patients from 16 healthy controls. This AD covariance pattern revealed hypoperfusion in bilateral inferior parietal lobule and cingulate; and left middle frontal, inferior frontal, precentral, and supramarginal gyri. The AD pattern also revealed hyperperfusion in bilateral insula, lingual gyri, and cuneus; left fusiform and superior occipital gyri; and right parahippocampal gyrus and pulvinar. In an independent sample of 23 outpatients with mild cognitive impairment (MCI) followed at 6-month intervals, the AD pattern score was evaluated as a predictor of cognitive decline. In this MCI sample, an H2(15)O resting PET scan was carried out at baseline. Mean duration of follow-up was 48.8 (SD 15.5) months, during which time six of 23 MCI patients converted to AD. In generalized estimating equations (GEE) analyses, controlling for age, sex, education, and baseline neuropsychological scores, increased AD pattern score was associated with greater decline in each neuropsychological test score over time (Mini Mental State Exam, Selective Reminding Test delayed recall, Animal Naming, WAIS-R digit symbol; Ps<0.01-0.001). In summary, a resting PET covariance pattern previously reported to discriminate AD patients from control subjects was applied prospectively to an independent sample of MCI patients and found to predict cognitive decline. Independent replication in larger samples is needed before clinical application can be considered. 相似文献
996.
997.
998.
Nicholas L. Shortt Gary F. Keenan Andrew Y. Muir Prof. Dr. A. Hamish R. W. Simpson 《Operative Orthopadie und Traumatologie》2006,18(4):364-376
OBJECTIVE: Avoidance of potential iatrogenic nerve injury during insertion of Ilizarov fine wires into areas of high anatomic risk by using a modified nerve stimulation technique. INDICATIONS: Application of the Ilizarov ring fixator to areas of high anatomic hazard, in situations where anatomic topography may be distorted by previous surgery, trauma, or congenital anomalies. CONTRAINDICATIONS: Use of systemic muscle relaxants. Caution in patient with cardiac pacemaker. SURGICAL TECHNIQUE: Preliminary experiments showed that a standard nerve-stimulating device can deliver a negatively charged, monophasic square pulse of current through Ilizarov wires. During the application of an Ilizarov frame to potentially hazardous anatomic regions, providing no systemic muscle relaxants are used, a voltage field sufficient to cause nerves in close proximity to the Ilizarov wire to depolarize is produced. Identification of a distal muscle twitch provoked by the stimulation may indicate a potential for iatrogenic nerve injury. RESULTS: Results show that with the nerve stimulator set at 2.5 mA (pulsed at a frequency of 2 Hz), peripheral nerves are stimulated if they lie within 5 mm of the wires. Should a distal muscle twitch occur, wires should be repositioned so that equivalent stimulation produces no twitch. The technique was used during Ilizarov frame application in ten patients, with only a single occurrence of distal muscle twitches in a lower-leg frame. Following repositioning of the Ilizarov wire in this case, no further twitches were observed, indicating that no Ilizarov wire was inserted close to peripheral nerves. No neurologic impairment was present postoperatively. 相似文献
999.
1000.