全文获取类型
收费全文 | 67095篇 |
免费 | 6526篇 |
国内免费 | 4375篇 |
专业分类
耳鼻咽喉 | 487篇 |
儿科学 | 1084篇 |
妇产科学 | 394篇 |
基础医学 | 5572篇 |
口腔科学 | 1289篇 |
临床医学 | 8887篇 |
内科学 | 7301篇 |
皮肤病学 | 661篇 |
神经病学 | 2243篇 |
特种医学 | 2099篇 |
外国民族医学 | 17篇 |
外科学 | 5623篇 |
综合类 | 16313篇 |
现状与发展 | 19篇 |
预防医学 | 6999篇 |
眼科学 | 1203篇 |
药学 | 7999篇 |
73篇 | |
中国医学 | 5795篇 |
肿瘤学 | 3938篇 |
出版年
2024年 | 289篇 |
2023年 | 959篇 |
2022年 | 2450篇 |
2021年 | 2990篇 |
2020年 | 2519篇 |
2019年 | 1689篇 |
2018年 | 1698篇 |
2017年 | 2100篇 |
2016年 | 1619篇 |
2015年 | 2893篇 |
2014年 | 3772篇 |
2013年 | 3923篇 |
2012年 | 6020篇 |
2011年 | 6179篇 |
2010年 | 5009篇 |
2009年 | 4438篇 |
2008年 | 4832篇 |
2007年 | 4727篇 |
2006年 | 4257篇 |
2005年 | 3454篇 |
2004年 | 2443篇 |
2003年 | 2057篇 |
2002年 | 1658篇 |
2001年 | 1419篇 |
2000年 | 1181篇 |
1999年 | 822篇 |
1998年 | 388篇 |
1997年 | 389篇 |
1996年 | 303篇 |
1995年 | 251篇 |
1994年 | 252篇 |
1993年 | 152篇 |
1992年 | 137篇 |
1991年 | 160篇 |
1990年 | 131篇 |
1989年 | 98篇 |
1988年 | 71篇 |
1987年 | 68篇 |
1986年 | 60篇 |
1985年 | 32篇 |
1984年 | 20篇 |
1983年 | 16篇 |
1982年 | 15篇 |
1981年 | 10篇 |
1979年 | 6篇 |
1958年 | 5篇 |
1956年 | 6篇 |
1955年 | 4篇 |
1954年 | 4篇 |
1948年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 21 毫秒
71.
北京石景山地区孕妇女婴幼儿血铅动态研究 总被引:8,自引:2,他引:6
在严格的质量保证措施下,北京石景山地区270名孕妇及其婴儿进行了血铅的追瞎调查。结果显示:孕3月血铅水平为45.0μg/L,分娩前血铅水平为64.8μg/L,孕期血铅呈升高趋势,其中后3月升高明显,分娩前血铅约为孕3月血铅的1.5倍;脐带血铅水平为51.9μg/L,其中有10.4%的胎儿脐血铅高于100μg/L; 相似文献
72.
Jin Jiabu Wang Yunxiang Qin Chaoji Department of Physiology Fourth Military Medical College Xi''''an 《中国人民解放军军医大学学报》1987,(3)
The effects of vagal and sympathetic nerves on the transmembranepotentials of cardiac cells of toad were observed by means of microelectrodetechnique.The vagal nerve was stimulated there would be an increase in restingpotential and acceleration in repolarization of action potential(AP).However,ifatropine was used before stimulation the above-mentioned phenomena woulddisappear.When the sympathetic nerve was stimulated the AP amplitudeincreased,but resting potential(RP)remained the same.The increase of APresulted from the increases of overshoot.When the sympathetic nerve wasstimulated although the heart rate increased and the duration of AP wasshortened,the plateau phase of AP was prolonged.These results suggest that theeffects of vagal and sympathetic nerves on the transmembrane potential of cardiacventricular cells are coordinated and the normal characteritics of transmembranepotential are maintained by both the vagal and sympathetic nerves. 相似文献
73.
目的 探讨使用猪尾造影导管与单一化疗药盒连接实现肝脏肿瘤多重化疗的可行性及初步疗效。资料与方法 对30例晚期肝脏恶性肿瘤患者采用经股动脉穿刺、腹腔动脉内植入猪尾导管与皮下埋置药盒并序贯化疗,统计手术成功率、并发症及临床疗效。结果 30例手术全部成功,发生切口延迟愈合1例。术后随访28例,经影像学复查对比,病变缩小7例,稳定12例,进展9例。随访期间12例患者死亡,术后生存期42d-10个月,中位生存期6个月。另外16例患者至今存活,已达术后2-16个月。结论 采用猪尾造影导管置于腹腔动脉并与化疗药盒相连接,能够对晚期肝脏恶性肿瘤实现多重化疗,技术上简单可行,并发症少,初步疗效令人满意。 相似文献
74.
通过平板初筛和摇瓶复筛,从371株菌中筛得一株有工业生产价值的胆固醇酯酶产生菌,并对它进行了发酵条件的研究。用所获得的胆固醇酯酶配制的三酶试剂具有良好的稳定性,适用于临床检测。 相似文献
75.
用复方泛影葡胺注射液对1,020例不孕症者作子宫输卵管造影。结果:子宫腔形态异常540例。双侧输卵管通畅但形态异常者268例。单侧输卵管通畅但形态异常者110例。结果表明:子宫输卵管形态异常与不孕有密切关系。 相似文献
76.
Azra Raza Harvey D. Preisler Ya Qin Li Richard A. Larson Jack Goldberg George Browman John Bennett Hans Grunwald Ralph Vogler Cathi Kukla 《American journal of hematology》1993,42(4):359-366
A pilot study was conducted of the biological characteristics of the leukemia cells of newly diagnosed patients with poor prognosis acute myelogenous leukemia (AML). This study included measurements of the pretherapy proliferative rate of the leukemia cells in vivo, assessment of differentiation in vivo during remission induction therapy, and the level of expression of the fms, myc, and IL1β genes in pretherapy leukemia cells. Short cell cycle times were characteristic of the best prognostic category and were associated with a rapid reduction in marrow leukemia cells in cytosine arabinoside (araC)-sensitive patients. Expression of c-fms was associated with rapid reduction in marrow leukemia cells during araC therapy and with a successful treatment outcome. Expression of the IL1β gene was associated with short remissions. These studies suggest that when compared to newly diagnosed standard prognosis AML, the leukemia of poor prognosis patients is more likely to exhibit long cell cycle times, low levels of fms expression, and is less likely to be associated with myeloid differentiation during remission induction therapy. © 1993 Wiley-Liss, Inc. 相似文献
77.
组织工程化肌腱研究进展 总被引:17,自引:2,他引:15
对组织工程化肌腱领域中目前研究的主要成果进行综述,着重阐述了肌腱细胞外基质替代物、肌腱细胞生物学性质及肌腱细胞与细胞外基质材料复合研究中的主要问题。认为,研制适于肌腱细胞生长、粘附和发挥功能的细胞外基质材料;建立生长、增殖可调控的肌腱细胞系;在模拟体内力学条件下,进行肌腱细胞三维培养,将是研究具有特定修复功能的组织工程化肌腱的重要问题。 相似文献
78.
目的 探讨大学生睡眠质量、负性情绪在错失恐惧与社交媒体倦怠间的中介作用。 方法 采用错失恐惧量表、社交媒体倦怠量表、匹兹堡睡眠质量指数量表、抑郁-焦虑-压力量表简体中文版对306名大学生进行调查。 结果 错失恐惧、社交媒体倦怠、睡眠质量和负性情绪之间呈两两正相关;错失恐惧能正向预测社交媒体倦怠;睡眠质量和负性情绪在错失恐惧和社交媒体倦怠之间起单独中介作用,且睡眠质量和负性情绪在错失恐惧与社交媒体倦怠之间起链式中介作用,负性情绪各维度效应皆成立。 结论 睡眠质量和负性情绪能够为错失恐惧对社交媒体倦怠的影响提供一个解释机制,大学生的错失恐惧既可以直接影响其社交媒体倦怠水平,也可以通过睡眠质量、负性情绪的独立中介效应以及睡眠质量-负性情绪的链式中介效应间接影响。 相似文献
79.
Adam J. Kaplan Kenneth D. Chavin Li Hui Qin Hideo Yagita Jonathan S. Bromberg 《Immunologic research》1994,13(1):42-48
The baculovirus expression system was used to produce three different constructs of the murine cell surface adhesion receptor CD2. One construct coded for a single, N-terminal, Ig-fold domain. It was inefficiently secreted and therefore primarily intracellular. The second construct coded for both extracellular, N-terminal Ig-fold domains. This was efficiently secreted into culture supernatant. The third construct coded for the full-length transmembrane molecule which localized to the cell surface. All constructs were monomers of predicted MWr and were appropriately glycosylated. They retained epitopic specificity as demonstrated by binding to mAbs, and adhesion function as demonstrated by a rosetting assay. 相似文献
80.
Cell extract-derived differentiation of embryonic stem cells 总被引:1,自引:0,他引:1
Various means have been used to encourage the differentiation of embryonic stem cells (ESCs) toward specific lineages, including growth factor administration, genetic modification, and coculture with relevant cells/tissues. Cell extract-based reprogramming has recently been used to derive mature cells from nonrelated phenotypes. In this communication, we tested whether this in vitro reprogramming approach can be used to direct ESC differentiation. Permeabilized murine ESCs exposed to extracts of murine type II pneumocytes showed increased expression of surfactant protein C and its corresponding mRNA, reflecting enhanced differentiation of pneumocytes. Subsequent differentiation to a type I phenotype was demonstrated by expression of aquaporin 5. Pneumocyte formation occurred quicker than with growth factor-induced differentiation. Our findings establish that ESCs can be differentiated in vitro using cellular extracts. This model provides a tool for analysis of the key factors involved in the differentiation of ESCs to type II pneumocytes. 相似文献