全文获取类型
收费全文 | 59691篇 |
免费 | 5618篇 |
国内免费 | 4102篇 |
专业分类
耳鼻咽喉 | 652篇 |
儿科学 | 600篇 |
妇产科学 | 570篇 |
基础医学 | 6193篇 |
口腔科学 | 888篇 |
临床医学 | 7564篇 |
内科学 | 8064篇 |
皮肤病学 | 573篇 |
神经病学 | 2839篇 |
特种医学 | 2304篇 |
外国民族医学 | 36篇 |
外科学 | 6487篇 |
综合类 | 10955篇 |
现状与发展 | 13篇 |
一般理论 | 3篇 |
预防医学 | 4203篇 |
眼科学 | 1654篇 |
药学 | 6400篇 |
67篇 | |
中国医学 | 4287篇 |
肿瘤学 | 5059篇 |
出版年
2025年 | 12篇 |
2024年 | 776篇 |
2023年 | 1119篇 |
2022年 | 2420篇 |
2021年 | 3024篇 |
2020年 | 2537篇 |
2019年 | 1901篇 |
2018年 | 2030篇 |
2017年 | 2027篇 |
2016年 | 1817篇 |
2015年 | 2902篇 |
2014年 | 3633篇 |
2013年 | 3341篇 |
2012年 | 4858篇 |
2011年 | 5187篇 |
2010年 | 3596篇 |
2009年 | 2911篇 |
2008年 | 3374篇 |
2007年 | 3125篇 |
2006年 | 3047篇 |
2005年 | 2811篇 |
2004年 | 1831篇 |
2003年 | 1740篇 |
2002年 | 1439篇 |
2001年 | 1186篇 |
2000年 | 1114篇 |
1999年 | 1054篇 |
1998年 | 657篇 |
1997年 | 589篇 |
1996年 | 483篇 |
1995年 | 453篇 |
1994年 | 344篇 |
1993年 | 259篇 |
1992年 | 315篇 |
1991年 | 307篇 |
1990年 | 210篇 |
1989年 | 163篇 |
1988年 | 184篇 |
1987年 | 154篇 |
1986年 | 101篇 |
1985年 | 80篇 |
1984年 | 60篇 |
1983年 | 32篇 |
1982年 | 29篇 |
1981年 | 31篇 |
1980年 | 23篇 |
1979年 | 38篇 |
1978年 | 13篇 |
1975年 | 11篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Marc D. Liang M.D. Krishna Narayanan M.D. Peter L. Davis M.D. J. William Futrell M.D. 《Aesthetic plastic surgery》1991,15(1):313-319
Magnetic resonance imaging (MRI) provides noninvasive images of facial and neck fat for a variety of conditions. It accurately maps the soft tissues pre- and postoperatively, enabling surgeons to precisely and objectively assess results of soft tissue facial contouring and fat transplantation. The risks of MRI are few. It has the potential to provide aesthetic surgeons with a more scientific means of comparing various techniques of fat contouring. 相似文献
102.
B S Liang 《中华预防医学杂志》1991,25(2):99-101
The ocular refraction was measured by applying 1% atropine eye-drops for 3 days in 5,458 eyes (male 2,944, female 2,514) of the pupils aged 7-17 in rural areas. The results were as follows: the majority of the pupils had hyperopia (male 84.71%, female 80.55%); the frequency of the measurements was not in normal distribution; the degree of far-sight began to recede and gradually become converted to myopias with advancing age but varying greatly between age-groups. The myopias began to appear at the age of 9 and increased rapidly at the age of 14 for girls and 15 for boys. From then on the rate of conversion continued to increase with schoolgirls more than schoolboys and, as a result, formed "the dangerous stage of myopia", the values of physiological visual refraction were shown as follows: pupils aged 7-9 + 2.00 D- + 2.50 D, aged 10-13 + 1.50 D- + 1.75 D, aged 14-17 + 1.00 D- + 1.25 D. The possibility of pathological hyperopia was greater if the pupils aged 7-9 and the value of visual refraction over +3.75 D, aged 10-13 had the value over +3.00 D and aged 14-17 had the value +2.50 D. The possibility of developing myopia was great in those pupils aged 7-9 whose value was under +1.00 D and in those aged 10-17 whose value was under +0.50 D. The deprived vision of the pupils should be routinely corrected by skiascopy. 相似文献
103.
罗通定中降解物巴马汀限量检测方法 总被引:4,自引:0,他引:4
目的:研究解决罗通定及硫酸罗通定注射液中降解物巴马汀的检测方法。方法:用薄层色谱法和紫外分光光度法限量检查样品中的巴马汀。结果:与对照品斑点大小、荧光强度比较和用吸收度限值控制均可对样品中的巴马汀进行限量检查,结果与原标准一致。结论:两方法均灵敏,专属,简便,快速。 相似文献
104.
药敏纸片的质量控制研究 总被引:1,自引:0,他引:1
目的:探讨和研究药敏纸片质量控制的方法。方法:以克拉霉素药敏纸片为例,参照美国临床实验室标准化委员会(NCCLS)和联邦法规全书(CFR)的方法,建立一套药敏纸片质量控制的指标,包括鉴别、检查及含量测定。结果:采用专属性较强、灵敏度较高的TLC法进行鉴别,最低检出量为50μg;制订纸片的的直径、重量差异、含量均匀性及干燥失重作为检查项,采用短小芽孢杆菌(Bacillus pumilus)[CMCC(B)63202]作为检定菌,进行含量测定。结论:建立的克拉霉素药敏纸片质量标准能够控制其质量,可作为其他抗生素药敏纸片建立质量标准的参考。 相似文献
105.
腹腔镜子宫次全切除术中超声刀的应用 总被引:5,自引:0,他引:5
目的 探讨超声刀在腹腔镜子宫次全切除术中的应用价值。方法 2 0 0 2年 1~ 12月在腹腔镜下分别应用超声刀和双极电凝及剪刀进行子宫次全切除术 ,比较术中出血量、手术时间、术后平均住院日及肛门排气时间。结果 超声刀组的平均手术时间、术中平均出血量显著少于双极电凝组 (P <0 0 1) ,术后平均住院日及肛门排气时间在两组间差异无显著性 (P >0 0 5 )。结论 超声刀可应用于妇科腹腔镜子宫次全切除术 ,由于其操作简单、安全可靠 ,值得推广。 相似文献
106.
目的 :研究LHRH拮抗剂Cetrorelix对子宫内膜癌细胞生长周期及周期相关蛋白的影响 ,探讨其抑制内膜癌细胞生长的机理。方法 :用流式细胞仪细胞周期分析及Westernblotting蛋白分析法 ,研究在Cetrorelix的作用下子宫内膜癌细胞系HEC 1A细胞生长周期及相关周期蛋白的改变。结果 :1 0 -5mol/LCetrorelix可导致HEC 1A细胞生长停滞于G2 /M期 ,而与G2 /M期停滞相关的p5 3 ,磷酸化p5 3 (phospho p5 3 ) (丝氨酸 3 92 )及磷酸化cdc2 (phospho cdc2 ) (酪氨酸 1 5 )蛋白水平均显著增高。结论 :Cetrorelix抑制内膜癌细胞增殖作用的机理是结合细胞表面受体后引起一系列抑制性信号传递 ,导致细胞周期停滞于G2 /M期 ,主要表现为G2 期停滞。其中p5 3激活及cdc2磷酸化失活是引起细胞周期停滞的重要因素 相似文献
107.
Effects of Aging and Advanced Glycation on Gene Expression in Cerebrum and Spleen of Mice^1 总被引:4,自引:0,他引:4
Liang YX Wang Z Li DD Jiang JM Shao RG 《Biomedical and environmental sciences : BES》2003,16(4):323-332
Objective To analyze the effects of aging or advanced glycation on gene expression in the cerebrum and spleen of female C57BL/6J mice. Methods The gene expression profile wasdetermined by using cDNA expression arrays containing 588 cDNA. 相似文献
108.
上颌磨牙近中颊根第二根管的定位 总被引:1,自引:0,他引:1
目的 通过对 77颗离体牙根管数目的检查 ,对近中颊根第二根管口 (MB2 )与近中颊根管口(MB)腭侧根管口 (P)的相对位置分布的规律进行观察分析 ,为临床治疗提供依据。方法 选择 77颗上颌离体牙 ,其中上颌第一磨牙 35颗 ,上颌第二磨牙 4 2颗 ,截冠后寻找近中颊根及其第二根管 ,并取得上颌恒磨牙根管口间距及根管口连线夹角等数据。结果 上颌第一、二恒磨牙近中颊根存在第二根管的有 36颗 ,占总数的 4 6 .75 % ,其中有1 5颗牙近中颊第二根管钙化不通 ,2 3颗牙近中颊根的第二根管口位于腭侧与近中颊第一根管口连线的近中处 ,近中颊根管口至近中颊第二根管口的距离为 1 .2 8± 0 .35 mm ,腭侧根管口至近中颊根管口的距离为 2 .98± 0 .4 7mm ,近中颊第二根管口至 P- MB线的垂直距离为 0 .6 3± 0 .1 2 mm,P- MB线与 MB- MB2 线的夹角为 2 5 .1 4°± 8.0 3°。结论 在上颌恒磨牙根管治疗时应注意根管系统的变异 ,改进开髓洞形 ,掌握查找近中颊根第二根管方法 ,以免遗漏根管 相似文献
109.
Time-dependent astroglial changes after gamma knife radiosurgery in the rat forebrain 总被引:11,自引:0,他引:11
OBJECTIVE: Using an experimental rat model and a clinically relevant treatment dose, we performed gamma knife radiosurgery to define the hyperacute radiation effects in normal rat forebrain, the time dependence of the astrocytic reaction, and the participation of astrocytes in the healing process after single-dose gamma radiation injuries. METHODS: Seventy-one rats underwent radiosurgical treatment (4-mm collimator) of the caudate-putamen nucleus (single-fraction maximal dose of 100 Gy) and were killed at times ranging from 3 hours to 90 days. Serial cryostat brain sections were processed with the immunohistochemical avidin-biotin complex technique, using anti-glial fibrillary acidic protein as the primary antibody (to identify astrocytes). RESULTS: Vascular changes, including endothelial hyperplasia and vessel wall thickening, were identified as the earliest postradiation manifestations and continued throughout the observation period. Astrocytes reacted to the radiation injury with hyperplasia and hypertrophy. At earlier time points (3-24 h), proliferation was the predominant reaction. The expression of glial fibrillary acidic protein in the proliferating and hypertrophic astrocytes formed an initial peak in the adjacent corpus callosum 3 days after radiosurgery and peaked within the target site between 14 and 30 days. Astrocytic proliferation and hypertrophy were also observed in distant cortices (frontal, parietal, insular, and piriform cortices) and in the hippocampus. No necrosis was observed less than 30 days after irradiation. By Day 90, necrotic lesions with a mean diameter of 4 mm were identified, with glial scar at their peripheries. Astrocytic morphological features varied according to the distance from the necrosis. The irradiated side contained more glial fibrillary acidic protein-containing cells than did the nonirradiated contralateral side. CONCLUSION: During the early phase after radiation, vasculopathy was the first morphological change and may serve as the initiating factor for subsequent changes. Reactive astrocytes appeared not only at the target site but also in the surrounding regions; the severity of injury was determined by the distance from the target. 相似文献