全文获取类型
收费全文 | 106759篇 |
免费 | 8906篇 |
国内免费 | 2865篇 |
专业分类
耳鼻咽喉 | 1497篇 |
儿科学 | 1574篇 |
妇产科学 | 1538篇 |
基础医学 | 15805篇 |
口腔科学 | 1957篇 |
临床医学 | 10448篇 |
内科学 | 19473篇 |
皮肤病学 | 3186篇 |
神经病学 | 8130篇 |
特种医学 | 5719篇 |
外国民族医学 | 8篇 |
外科学 | 12336篇 |
综合类 | 5799篇 |
现状与发展 | 5篇 |
一般理论 | 23篇 |
预防医学 | 6666篇 |
眼科学 | 2593篇 |
药学 | 10404篇 |
18篇 | |
中国医学 | 3092篇 |
肿瘤学 | 8259篇 |
出版年
2024年 | 241篇 |
2023年 | 1101篇 |
2022年 | 2699篇 |
2021年 | 3901篇 |
2020年 | 2302篇 |
2019年 | 2797篇 |
2018年 | 3178篇 |
2017年 | 2684篇 |
2016年 | 3408篇 |
2015年 | 4562篇 |
2014年 | 5290篇 |
2013年 | 5887篇 |
2012年 | 8476篇 |
2011年 | 8406篇 |
2010年 | 5166篇 |
2009年 | 4326篇 |
2008年 | 5817篇 |
2007年 | 5673篇 |
2006年 | 5152篇 |
2005年 | 4887篇 |
2004年 | 3971篇 |
2003年 | 3768篇 |
2002年 | 3345篇 |
2001年 | 2596篇 |
2000年 | 2305篇 |
1999年 | 1853篇 |
1998年 | 896篇 |
1997年 | 784篇 |
1996年 | 639篇 |
1995年 | 555篇 |
1994年 | 509篇 |
1993年 | 456篇 |
1992年 | 862篇 |
1991年 | 896篇 |
1990年 | 816篇 |
1989年 | 807篇 |
1988年 | 773篇 |
1987年 | 740篇 |
1986年 | 643篇 |
1985年 | 594篇 |
1984年 | 454篇 |
1983年 | 371篇 |
1982年 | 279篇 |
1981年 | 274篇 |
1980年 | 225篇 |
1979年 | 334篇 |
1978年 | 281篇 |
1977年 | 208篇 |
1974年 | 223篇 |
1973年 | 237篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
目的 探讨一种高效便捷的99mTc CEA Fab标记化合物的研制方法。方法 采用 2 亚氨噻酚盐酸盐修饰CEA Fab ,通过GH转换 ,将99mTc标记在结肠癌单克隆抗体CEA Fab上。结果 已修饰抗体的标记率为 93.5 %,99mTc胶体含量为 2 .5 %,标记化合物有良好的稳定性和免疫活性。结论 成功地建立了结肠癌单抗片断CEA Fab的99mTc标记方法 ,该技术可以应用于其他抗体片段标记领域。 相似文献
53.
54.
In vivo voltammetry at chronically implanted carbon paste electrodes in unrestrained rats is a particularly useful technique for evaluating neurochemical changes during spontaneous behaviour, or behaviour under experimental control. A 3 peak signal is observed in the striatum; most recently the consensus view has attributed these peaks to ascorbic acid (AA), uric acid (UA) and homovanillic acid (HVA) in ascending order of oxidation potential. We have used a pharmacological approach, combined with in vivo dialysis, to further elucidate the nature of the contributing species. Allopurinol, an inhibitor of xanthine oxidase, and thus of uric acid production, has previously been reported to abolish peak 2. We now report, using dialysis, that it selectively depletes UA in the extracellular fluid (ECF). Pargyline, a monoamine oxidase inhibitor, reduces peak 3 transiently (max. 60%) as expected, however it results in a more sustained reduction in ECF HVA (max. 100%). It also increases peak 1 (max. 75%) and decreases peak 2 (max. 40%), although changes in ECF AA and UA measured by dialysis and HPLC are minimal. Pargyline does however reduce ECF 5-hydroxyindoleacetic acid by 65%. We conclude that, using linear sweep voltammetry at chronically implanted paste electrodes: (a) one or more substances in addition to AA can contribute to peak 1; dopamine can do so in some situations; (b) 5-hydroxyindoleacetic acid, as well as UA, contributes to peak 2; its contribution is about one third that of the latter; and (c) one or more substances in addition to HVA can contribute to peak 3. 3-Methoxytyramine can do so. Since this is another methylated metabolite of dopamine, this does not prevent the use of peak 3 as an index of dopamine metabolism, and may extend its usefulness to situations where monoamine oxidase is inhibited. 相似文献
55.
护理作为一门独立的专业,其发展应以科学研究为基础。护理科研、论文的数量和水平是评价一个地区或单位的护理整体水平的重要指标之一。笔者通过我院10年间医院工作人员科研立项、科研论文发表交流情况及护理人员论文写作的调查,对护理科研滞后的应用进行了综合分析,认为缺乏科研意识、科研潜力不足,观行制度制约,客观条件制约是重要因素。提出改变这种状态应从学科带头人入手,详细阐述了护士长对护理科研、论文工作的指导。 相似文献
56.
Duk Hyun Sung Joon Young Choi Du-Hwan Kim Eun-Sang Kim Young-Ik Son Young-Seok Cho Su Jin Lee Kyung-Han Lee Byung-Tae Kim 《Journal of nuclear medicine》2007,48(11):1790-1795
The purpose of this study was to investigate whether (18)F-FDG PET/CT is useful for localizing dystonic cervical muscles in patients with idiopathic cervical dystonia (ICD) by comparing disease severity before and disease severity after botulinum toxin (BT) injection into hypermetabolic muscles. METHODS: Six patients with ICD underwent (18)F-FDG PET/CT. Dystonic muscles suitable for BT injection therapy were defined as those showing diffusely increased (18)F-FDG uptake. RESULTS: Hypermetabolic cervical muscles were identified in all 6 patients. In 2 patients who underwent PET/CT both in a supine position and in a sitting position during (18)F-FDG uptake, abnormal hypermetabolic muscles were observed by PET/CT only when patients were in the sitting position with their heads and necks in the adopted abnormal involuntary posture. Symptoms were significantly improved in 4 patients who underwent BT injection therapy guided by PET/CT and who were clinically monitored. CONCLUSION: (18)F-FDG PET/CT is potentially useful for identifying dystonic cervical muscles for BT therapy in patients with ICD. 相似文献
57.
Eun Hee Sohn Chang Joon Song Hyo-Jin Lee Samyong Kim Jae-Moon Kim Ae Young Lee 《JOURNAL OF CLINICAL NEUROLOGY》2007,3(2):108-111
Lymphomatoid granulomatosis (LG) is a potentially malignant lymphoproliferative disorder. The lung is the most common involved site, followed by the skin and nervous system. However, LG of the central nervous system presenting with Parkinsonism is very rare. We report a patient with LG who presented with parkinsonian features such as bilateral rigidity, bradykinesia, and agitation. Brain magnetic resonance imaging showed multifocal punctuate enhanced lesions in both supra- and infratentorial areas. Steroid pulse therapy resulted in a dramatical improvement in the symptoms and MRI abnormalities. 相似文献
58.
目的探讨散发型Creutzfeldt-Jakob病(sCJD)的MR特点。方法回顾性分析3例临床诊断为sCJD的患者资料,MR采用SE T1 WI、快速自旋回波(FSE)T2 WI、扩散加权成像(DWI)扫描,观察其MR表现特征。结果3例SE TI WI和FSE T2 WI序列对基底节区和皮质的病变显示不佳,DWI则可清晰地显示病变,额、顶、枕叶皮质最常受累,表现为高信号,病变可对称,也可不对称,皮层下区脑白质信号未见异常。双侧尾状核、丘脑也可受累,DWI上呈高信号。晚期脑实质广泛萎缩,以皮质为著。结论sCJD采用DWI序列结合其特征性的临床表现可作出较为准确的诊断。 相似文献
59.
In cases of displaced greater tuberosity fractures, treatments by arthroscopic-assisted reduction and percutaneous screw fixation have been reported. However, in cases in which there is a comminuted fracture or a minimally displaced fracture combined with concomitant lesions such as rotator cuff tear or labral pathology, it is difficult to reduce the fracture and to treat other pathologies by use of a percutaneous screw. Recently, many surgeons have used the double-row repair method in rotator cuff repair, which provides a tendon-bone interface better suited for biologic healing and restoring normal anatomy. In accordance with this method, we used the arthroscopic technique of double-row suture anchor fixation for a minimally displaced greater tuberosity fracture without additional incision. Initially, debridement was performed on the fracture surface by use of a shaver, and the medial-row anchor was inserted through the anterior portal or the intact cuff. Two lateral-row anchors were inserted just anterior and posterior to the lower margin of the fractured fragment under C-arm guidance. The medial-row sutures and lateral-row sutures were then placed. Arthroscopic double-row suture anchor fixation of a displaced greater tuberosity fracture restores the original footprint of the rotator cuff and normal tendon-bone interface of the displaced greater tuberosity fracture. 相似文献
60.