全文获取类型
收费全文 | 374624篇 |
免费 | 34723篇 |
国内免费 | 26043篇 |
专业分类
耳鼻咽喉 | 2848篇 |
儿科学 | 4896篇 |
妇产科学 | 4195篇 |
基础医学 | 41087篇 |
口腔科学 | 6128篇 |
临床医学 | 52886篇 |
内科学 | 50688篇 |
皮肤病学 | 4137篇 |
神经病学 | 18172篇 |
特种医学 | 13777篇 |
外国民族医学 | 224篇 |
外科学 | 33092篇 |
综合类 | 69955篇 |
现状与发展 | 86篇 |
一般理论 | 31篇 |
预防医学 | 27571篇 |
眼科学 | 10685篇 |
药学 | 40680篇 |
436篇 | |
中国医学 | 24418篇 |
肿瘤学 | 29398篇 |
出版年
2024年 | 1280篇 |
2023年 | 5460篇 |
2022年 | 14407篇 |
2021年 | 18332篇 |
2020年 | 14411篇 |
2019年 | 11791篇 |
2018年 | 12167篇 |
2017年 | 11672篇 |
2016年 | 10780篇 |
2015年 | 16831篇 |
2014年 | 20948篇 |
2013年 | 19054篇 |
2012年 | 28354篇 |
2011年 | 31876篇 |
2010年 | 21501篇 |
2009年 | 17502篇 |
2008年 | 21389篇 |
2007年 | 21106篇 |
2006年 | 20139篇 |
2005年 | 19225篇 |
2004年 | 12701篇 |
2003年 | 12229篇 |
2002年 | 10004篇 |
2001年 | 8531篇 |
2000年 | 8320篇 |
1999年 | 8394篇 |
1998年 | 5300篇 |
1997年 | 5093篇 |
1996年 | 3957篇 |
1995年 | 3713篇 |
1994年 | 3134篇 |
1993年 | 2026篇 |
1992年 | 2426篇 |
1991年 | 2126篇 |
1990年 | 1792篇 |
1989年 | 1556篇 |
1988年 | 1283篇 |
1987年 | 1183篇 |
1986年 | 955篇 |
1985年 | 676篇 |
1984年 | 369篇 |
1983年 | 271篇 |
1982年 | 142篇 |
1981年 | 169篇 |
1980年 | 115篇 |
1979年 | 154篇 |
1978年 | 73篇 |
1977年 | 53篇 |
1974年 | 42篇 |
1972年 | 37篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
影响脐血IgE值因素的研究 总被引:2,自引:0,他引:2
目的 本研究对影响脐血IgE值的可疑因素进行分析 ,探讨影响儿童食物过敏的可疑因素。方法 选取孕期妇女 10 5名及其所生婴儿 ,采用标准问卷调查获取资料 ,对影响脐血IgE的因素进行分析。 结果 母亲的过敏性疾病史、父亲过敏性疾病史中的皮炎表现型、孕期妇女过敏性疾病发作史、有过敏史妇女孕后期摄入过量的牛奶和鸡蛋均与脐血IgE值的上升有关 ,且上述 5个因素对脐血IgE水平的影响依次降低。 结论 母亲的过敏性疾病史和父亲过敏性疾病史中的皮炎表现型是导致新生儿脐血IgE值升高的主要危险因素 ;同时 ,妊娠期加强对有过敏史妇女的保护 ,防止过敏性疾病的复发 ,在孕后期控制有过敏史妇女牛奶、鸡蛋等大分子食物致敏原的摄入 ,有助于降低脐血IgE值。 相似文献
52.
53.
目的 探讨脑梗死后抑郁与负性生活事件的关系。方法 将脑梗死患者按是否受负性生活事件影响分为 A(n=75 )、B(n=73)两组。采用抑郁自评量表 (SDS)及 Hamilton抑郁量表筛查 ,对两组进行比较分析 ,并观察其治疗效果。结果 A、B两组脑梗死后抑郁的发生率分别为 5 6 %、38.4 % ,两者比较差异显著 (P<0 .0 5 ) ;百忧解可显著改善或治愈脑梗死后抑郁 ,总有效率 6 1.7%。结论 脑梗死后抑郁发生与负性生活事件相关。百忧解治疗有效 相似文献
54.
55.
56.
A difference spectrophotometric procedure is described for the assay of nitrazepam in tablet formulations. The method is based on the measurement of absorbance at 282 nm of a solution of the tablet extract in 0.1 M hydrochloric acid (pH 1) relative to that of an equimolar solution in 0.1 M sodium hydroxide (pH 13). The method is precise and selective for nitrazepam in the presence of the tablet excipients and 2-amino-5-nitrobenzophenone, the principal hydrolysis product of nitrazepam. The absence of a constant isosbestic point in the difference spectrum of nitrazepam during hydrolysis in alkaline solution indicates the presence of a previously unrecognized intermediate hydrolysis product. 相似文献
57.
豚鼠内耳磁微粒栓塞缺血模型初探 总被引:3,自引:0,他引:3
OBJECTIVE: To set up an inner ear ischemic model in guinea pig with ferromagnetic embolism. METHODS: A magnet was fitted in the external auditory canal and carbonyl iron filings (1%, 1 ml/kg) was injected into jugular, then the inner ear vessels were obstructed by ferromagnetic spheres. Cochlear blood flow (CBF) and number of red blood cells in the stria vessels were used to detect the model's ischemia of cochleae. The slice of temple bone and basal membrane stained by silver nitrate were used for inner ear's histopathological observations. RESULTS: The iron spheres were amassed in the one and two-day-later's model of inner ear vessels, which resulted in embolism. The number of red blood cells in the stria vessels decreased and then recovered to normal level after 4 days, but the CBF decreased to 50% +/- 10% of basic level immediately and recovered to 99% +/- 41% 4 days later. Scattered lesion of out hair cell cilium could be seen in cochleae in eight-day-later's model, and degenerations in different degree were found in vascular stria. CONCLUSION: The methods of inner ear ischemic model with ferromagnetic embolism could be practical and the decrease of CBF was reversible, so it may be an ideal model for studying some ischemic inner ear diseases and evaluating the effects of therapeutic drugs. 相似文献
58.
本文报道给家兔注入不同剂量的~3H-α-第二丁基对羟基苄醇,观察该药在其体内的药物动力学。结果表明,血中分布相快,消除相慢,消除半衰期T_1/1β为12h。经F值检验和理论计算值与实测值的契合程度比较,表明该药在兔体内的运转符合二室开放模型的动力学方程。 相似文献
59.
The effects of localized gamma-irradiation on the in vivo 31P NMR spectra of RIF-1 tumors grown subcutaneously in C3H/HeN mice have been examined before and during the week after treatment. Increases in the ratio of phosphocreatine (PCr) to inorganic phosphate (Pi) and in tumor pH, and decreases in the ratio of Pi to the beta phosphorus resonance of the nucleotide triphosphates (beta NTP) were observed in irradiated tumors. The time course of changes in the 31P spectrum following treatment was the opposite of the pattern during untreated growth, and the magnitude and duration of the changes increased with increasing radiation dose, decreasing clonogenic cell survival and increasing growth delay. To examine the possibility that nontherapeutic systemic effects of the tumor irradiation were responsible for the changes observed, a number of animals bearing two tumors were examined. One tumor on each mouse was selectively irradiated. Changes in tumor volume, Pi/beta NTP, PCr/Pi, the ratio of phosphomonoesters to beta NTP, and tumor pH were all significantly different in the treated compared to the untreated tumor on each animal, indicating that these changes in 31P NMR spectra were a response to radiation therapy and not a systemic response to radiation toxicity. 相似文献
60.
The historical review and the necessity of establishment of the Chinese Classification of Diseases (CCD) and Coding System are described. The content, terms used for unified and standardized nomenclatures, coding system including diagnostic terms of traditional Chinese medicine and other codings are introduced. The utility of the CCD system in medical record face sheet management, national native medical statistics, consultative retrieval from terms and codes of diseases, the development and practical trial of ICD-9 CCD is also discussed. Finally, the position and prospect of CCD system in international informatics communication is emphasized. 相似文献