全文获取类型
收费全文 | 133615篇 |
免费 | 11533篇 |
国内免费 | 7651篇 |
专业分类
耳鼻咽喉 | 1273篇 |
儿科学 | 2172篇 |
妇产科学 | 1097篇 |
基础医学 | 12321篇 |
口腔科学 | 2296篇 |
临床医学 | 16753篇 |
内科学 | 16431篇 |
皮肤病学 | 1933篇 |
神经病学 | 5163篇 |
特种医学 | 5242篇 |
外国民族医学 | 26篇 |
外科学 | 11816篇 |
综合类 | 28867篇 |
现状与发展 | 28篇 |
一般理论 | 7篇 |
预防医学 | 13112篇 |
眼科学 | 2669篇 |
药学 | 14588篇 |
120篇 | |
中国医学 | 8778篇 |
肿瘤学 | 8107篇 |
出版年
2024年 | 376篇 |
2023年 | 1320篇 |
2022年 | 3377篇 |
2021年 | 4552篇 |
2020年 | 3728篇 |
2019年 | 2834篇 |
2018年 | 2952篇 |
2017年 | 3402篇 |
2016年 | 3244篇 |
2015年 | 5276篇 |
2014年 | 6877篇 |
2013年 | 7807篇 |
2012年 | 11295篇 |
2011年 | 11961篇 |
2010年 | 9680篇 |
2009年 | 8518篇 |
2008年 | 9546篇 |
2007年 | 9438篇 |
2006年 | 8598篇 |
2005年 | 7568篇 |
2004年 | 5831篇 |
2003年 | 5733篇 |
2002年 | 4535篇 |
2001年 | 3701篇 |
2000年 | 2808篇 |
1999年 | 1767篇 |
1998年 | 902篇 |
1997年 | 954篇 |
1996年 | 649篇 |
1995年 | 562篇 |
1994年 | 475篇 |
1993年 | 330篇 |
1992年 | 351篇 |
1991年 | 294篇 |
1990年 | 256篇 |
1989年 | 216篇 |
1988年 | 176篇 |
1987年 | 164篇 |
1986年 | 127篇 |
1985年 | 121篇 |
1984年 | 71篇 |
1983年 | 56篇 |
1982年 | 40篇 |
1981年 | 31篇 |
1980年 | 20篇 |
1979年 | 37篇 |
1978年 | 34篇 |
1976年 | 23篇 |
1973年 | 27篇 |
1970年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 5 毫秒
51.
缺血再灌流肾组织内皮素—1动态变化的实验研究 总被引:7,自引:1,他引:6
在大鼠肾缺血60分钟再灌注的模型上观察不同时相肾静脉血、肾皮质、外髓和内髓的内皮素1(ET1)浓度变化,肾组织ET1光镜和电镜免疫组织化学变化。结果发现:缺血再灌流肾组织ET1基因表达及分泌明显增强,主要分布在血管内皮细胞及平滑肌细胞、系膜细胞、肾小管上皮细胞。其分布特点与细胞类型和活性有关。本实验结果提示了缺血再灌注肾内ET1的变化规律。 相似文献
52.
53.
BACKGROUND: Chronic mucocutaneous candidiasis (CMC) is a rare disorder characterized by persistent or recurrent candidal infections of the skin, nails and mucous membranes or by a variable combination of endocrine failure as well as immunodeficiency. Oral clinicopathological features of CMC have seldom been described in detail. METHODS: Seven patients with CMC were reported in the study. The clinical and histological findings, etiological Candida species, immunological evaluation, and therapeutic pattern of oral lesions, were analyzed. RESULTS: Long-standing whitish hyperplastic and nodule-like lesions with exaggerated deep fissure were the typical and characteristic oral manifestations presented by all patients. The tongue was the most common site affected. Histologically, no obvious distinction was found between CMC and other forms of candidal infection. Abnormal proportions of T-lymphocyte subsets and positive titers of autoantibody were observed in three subjects (42.9%) and one patient (14.3%) respectively. Meanwhile, four subjects (57.1%) showed decreased albumin and increased globulin, three cases (42.9%) had high levels of ESR. But no iron deficiency was found. Candida albicans was the microorganism isolated from these patients. CONCLUSIONS: Multiple and widespread candidal infectious lesions can be observed on the oral cavity of CMC patients. Hyperplastic and nodule-like lesion with irremovable whitish patches and deep fissure are the most common oral manifestations of these patients. Dentists, otolaryngologists and pediatricians should be familiar with the clinical appearances of CMC to make an accurate diagnosis. Potential systemic disorders should be concerned to avoid the reoccurrence of oral candidiasis. 相似文献
54.
目的:探讨经尿道等离子前列腺双极汽化电切术(TUPKVP)治疗前列腺增生的效果。方法:回顾性分析580例良性前列腺增生(BPH)患者行TUPKVP的临床资料。结果:中转开放手术2例,切除前列腺组织10~80 g,平均32.5 g。手术时间25~150 min,平均60 min,术中输血10例,无电切综合征(TURS)发生。术后随访2~36个月,患者最大尿流率升高,IPSS症状评分值降低,排尿通畅,疗效好,并发症少。结论:TUPKVP出血少,手术安全,疗效确切,是治疗前列腺增生的有效方法。 相似文献
55.
PURPOSE: To examine the relationship between ametropia and optical aberrations in a population of 200 normal human eyes with refractive errors spanning the range from +5.00 to -10.00 D. METHODS: Using a reduced-eye model of ametropia, we tested the hypothesis that the optical system of the eye is uncorrelated with the degree of ametropia. These predictions were evaluated experimentally with a Shack-Hartmann aberrometer that measured the monochromatic aberrations across the central 6 mm of the dilated pupil in well-corrected, cyclopleged eyes. RESULTS: Optical theory predicted, and control experiments on a model eye verified, that Shack-Hartmann measurements of spherical aberration will vary with axial elongation of the eye even if the dioptric components of the eye are fixed. Contrary to these predictions, spherical aberration was not significantly different from emmetropic eyes. Root mean square of third-order aberrations, fourth-order aberrations, and total higher aberrations (third to 10th) in myopic and hyperopic eyes were also uncorrelated with refractive error. Astigmatic eyes tended to have larger total higher-order aberrations than nonastigmatic eyes. CONCLUSIONS: We conclude that a reduced-eye model of myopia assuming fixed optical parameters and variable axial length is not tenable. 相似文献
56.
Xin Hong Larry N Thibos Arthur Bradley Russell L Woods Raymond A Applegate 《Optometry and vision science》2003,80(1):15-25
Repeated measures of wavefront aberrations were taken along the line-of-sight of seven eyes using two instruments: an objective, cross-cylinder aberroscope (OA) and a Shack-Hartmann (SH) aberrometer. Both instruments were implemented on the same optical table to facilitate interleaved measurements on the same eyes under similar experimental conditions. Variability of repeated measures of individual coefficients tended to be much greater for OA data than for SH data. Although Zernike coefficients obtained from a single measurement were generally larger when measured with the OA than with the SH, the averages across five trials were often smaller for the OA. The Zernike coefficients obtained from the two instruments were not significantly correlated. Radial modulation-transfer functions and point-spread functions derived from the two sets of measurements were similar for some subjects, but not all. When average Zernike coefficients were used to determine optical quality, the OA indicated superior optics in some eyes, but the reverse trend was true if Zernike coefficients from individual trials were used. Possible reasons for discrepancies between the OA and SH measurements include difference in sampling density, quality of data images, alignment errors, and temporal fluctuations. Multivariate statistical analysis indicated that the SH aberrometer discriminated between subjects much better than did the objective aberroscope. 相似文献
57.
Anatomic and spiral computed tomographic study of the genial tubercles for genioglossus advancement.
Shan Kai Yin Hong Liang Yi Wen Ying Lu Jian Guan Hong Min Wu Zhen Yu Cao Dong Zhen Yu Yan Yan Huang Chun Gen Wu 《Otolaryngology--head and neck surgery》2007,136(4):632-637
OBJECTIVE: To measure and compare Chinese mandibular genial tubercles measured anatomically and with computed tomography (CT). STUDY DESIGN AND SETTING: Spiral CT scans were taken of 40 adult human skulls; the superior genial spines were measured using anatomic and CT methods. RESULTS: The height and width of the superior genial spines, mandible thickness, and distance from the menton to the inferior and superior margins of the superior genial spines were 5.82 +/- 0.71, 6.98 +/- 1.35, 11.95 +/- 1.59, 11.08 +/- 2.05, and 16.91 +/- 2.30 mm from anatomic measurements and 6.17 +/- 0.71, 7.01 +/- 1.13, 12.19 +/- 1.64, 10.41 +/- 1.55, and 15.73 +/- 2.12 mm using spiral CT, respectively. The anatomic and CT measurements were correlated. CONCLUSION: Spiral CT of the genial tubercles can help locate the osteotomy in genioglossus advancement. SIGNIFICANCE: This study acquired reference data on Chinese genial tubercles demonstrating that CT measurements of the genial tubercles reflect their anatomy, which should allow accurately locate the osteotomy. 相似文献
58.
妇科腹腔镜手术中转开腹原因分析 总被引:2,自引:1,他引:1
目的探讨妇科腹腔镜手术中转开腹的原因。方法对1234例妇科腹腔镜手术中的中转开腹患者的病情进行总结分析。结果16例腹腔镜中转开腹患者中,盆腔严重粘连者7例,盆腔恶性肿瘤4例,其他5例。结论盆腔严重粘连和盆腔恶性肿瘤是妇科腹腔镜手术中转开腹的主要原因,术前、术中充分的病情评估可能有助于减少中转开腹的发生。 相似文献
59.
对1997年以来423例病态喉的频闪喉镜表现进行分析,结果显示声带有病理改变者其粘膜波、振幅、闭合相、运动周期性、对称性均有不同程度的变化,这种变化能直接反映声带病变的深度及范围,对喉部疾病的诊断、鉴别诊断、治疗指导及预后评价具有重要意义. 相似文献
60.
Photic evoked responses were recorded from the striate cortex of Long-Evans hooded intact, monocular visual deprivation (MD) and MD treated with NGF rats. The averaged visual evoked responses (AVER) were obtained from both hemispheres and provided comparison after binocular photic stimuli between the contralateral and the ipsilateral striate cortex with relation to the MD eye. One month of monocular visual deprivation at the critical period of development resulted in marked reduction of the amplitudes of AVER components as compared to the control recordings (P < 0.001). These changes of the AVER could be prevented by NGF infusion to lateral ventricle at the dosage of 2.0–2.4 μg/day for four weeks during the monocular deprivation. In conclusion, the change of AVER amplitudes induced by monocular visual deprivation during the critical period of development can be prevented by NGF infusion to lateral ventricle. 相似文献