全文获取类型
收费全文 | 13141篇 |
免费 | 903篇 |
国内免费 | 408篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 47篇 |
妇产科学 | 13篇 |
基础医学 | 1020篇 |
口腔科学 | 5894篇 |
临床医学 | 618篇 |
内科学 | 407篇 |
皮肤病学 | 86篇 |
神经病学 | 1525篇 |
特种医学 | 256篇 |
外国民族医学 | 1篇 |
外科学 | 875篇 |
综合类 | 1695篇 |
预防医学 | 236篇 |
眼科学 | 14篇 |
药学 | 735篇 |
3篇 | |
中国医学 | 921篇 |
肿瘤学 | 69篇 |
出版年
2024年 | 33篇 |
2023年 | 259篇 |
2022年 | 337篇 |
2021年 | 512篇 |
2020年 | 440篇 |
2019年 | 416篇 |
2018年 | 414篇 |
2017年 | 425篇 |
2016年 | 459篇 |
2015年 | 452篇 |
2014年 | 822篇 |
2013年 | 795篇 |
2012年 | 747篇 |
2011年 | 879篇 |
2010年 | 670篇 |
2009年 | 544篇 |
2008年 | 617篇 |
2007年 | 666篇 |
2006年 | 596篇 |
2005年 | 524篇 |
2004年 | 442篇 |
2003年 | 432篇 |
2002年 | 374篇 |
2001年 | 332篇 |
2000年 | 255篇 |
1999年 | 215篇 |
1998年 | 225篇 |
1997年 | 159篇 |
1996年 | 150篇 |
1995年 | 114篇 |
1994年 | 127篇 |
1993年 | 129篇 |
1992年 | 104篇 |
1991年 | 86篇 |
1990年 | 83篇 |
1989年 | 75篇 |
1988年 | 75篇 |
1987年 | 50篇 |
1986年 | 75篇 |
1985年 | 80篇 |
1984年 | 48篇 |
1983年 | 36篇 |
1982年 | 38篇 |
1981年 | 32篇 |
1980年 | 46篇 |
1979年 | 16篇 |
1978年 | 11篇 |
1977年 | 7篇 |
1974年 | 6篇 |
1972年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
51.
The antimicrobial effects of a saturated calcium hydroxide solution, and in combination with 10% and 20% detergent, were evaluated on Streptococcus faecalis. Strepto-coccus sanguis, Streptococcus mutans, Streptococcus salivarius, Neisseria sp., diphlheroid, Staphylococcus aureus, Lactobacillus sp., Staphylococcus epidermidis, Bacillus suhtilis and Candida albicans. The saturated calcium hydroxide solution was effective against only four of the 11 microorganisms studied over a 60-min exposure time. The calcium hydroxide solutions con-taining detergent killed all 11 test organisms over a 30-min exposure time. This difference was statistically significant (P<0.01). No statistically significant difference in antimicrobial action was found between the 10% and 20% detergent calcium hydroxide solutions (F>0.01). However, the low surface tension (46.5 × 10?3 Nm?1) and high pH (10.8) of the calcium hydroxide solution with 20% detergent establish it as the more effective solution. 相似文献
52.
从34例牙髓根管感染中共分离出厌氧菌118株,经菌属分类依次为消化链球菌属,拟杆菌属,梭杆菌属,放线菌属,韦荣氏球菌属和珠网菌属,其中前3属为77株,分离率为65.3%,这一结果显示该3属细菌与极管感染有密切关系,是牙髓根管感染的优势菌。 相似文献
53.
The present investigation introduces an in vitro model to study macrophage properties during demyelination. Rat dorsal root ganglia (DRG) were cultured for obtaining myelinated peripheral nerve fibers. These cultures were exposed to non-resident macrophages. In untreated control cultures, there was no indication of myelin removal by the added macrophages. DRG were exposed to enzymatically generated oxygen radicals using the xanthin/xanthin oxidase or the glucose/glucose oxidase system. Assessment of Schwann cell viability and ultrastructural morphology revealed different patterns of cell cytotoxicity and morphological changes in different experiments. High concentrations caused complete tissue necrosis of the DRG, while low concentrations did not affect either cell viability or ultrastructural morphology. Under intermediate experimental conditions, oxygen radicals caused non-lethal Schwann cell damage leading to Schwann cell retraction and myelin sheath rejection. Myelin lamellae were disrupted and decompacted. These changes were followed by a selective macrophage attack on myelin sheats, resulting in demyelination. Axons, Schwann cells and sensory ganglion cells survived this attack. The specificity of the oxygen radical effects was tested in experiments using the oxygen radical scavengers catalase and superoxide dismutase. Catalase prevented the described effects on cell morphology and subsequently blocked demyelination by non-resident macrophages.Supported by a grant from the Deutsche Forschungsgemeinschaft (DFG) (Br 1274/1-1) 相似文献
54.
本文对136例口腔颌面部损伤的伤因,颌骨骨折、牙损伤及软组织损伤等情况进行了分析。讨论了口腔颌面外伤的特点、急救处理、及骨折线上牙齿的处理等问题。强调对颌面外伤的处理必须注重整体观念。 相似文献
55.
56.
Summary The aim was to develop a model for study of nerve regeneration in nerve roots above the level of the dorsal root ganglion and to investigate the use of freeze-thawed muscle autografts for repair of nerve roots at this level.Four adult sheep were used for the experiment. A laminectomy was performed at the lumbosacral junction and the S2 root identified. Both the dorsal and ventral S2 roots were divided unilaterally within the dura and a freeze-thawed muscle graft was inserted into the nerve gap.When assessed at 6 months an action potential was recordable from the ventral root in one sheep. Histological examination of the nerve roots showed evidence of regeneration across the graft in the ventral roots of all the sheep and the dorsal roots of some.This preliminary work indicates a capacity for regeneration of the cauda equina and that freeze-thawed muscle can support this. It provides a useful model for further study of nerve root repair. 相似文献
57.
H. Oka T. Yamamoto T. Kawazoe K. Saratani Y. Hikida 《Medical & biological engineering & computing》1988,26(3):260-266
A new impact response method using a fracture of a pencil-lead to produce an excitation pulse is proposed. Impact excitations
(rectangular pulse, triangular pulse and half-sine pulse) are strictly given in physical and mathematical definitions and
complete solutions to the impact excitations are provided for Noyes' model of the human tooth. When a relatively long triangular
pulse is applied to Noyes' model, which can express the physical characteristic of periodontal tissues, a sinusoidal damped
vibration of a single degree-of-freedom model is approximately obtained. The acceleration response is characterised by the
physical parameters (T, δ and Ao) and mechanical elements (m1, c1 and k) of which a single degree-of-freedom model is composed. By means of this method, the values of the parameters and elements
in the cases of healthy maxillary, healthy mandibular and pathological mandibular incisors are obtained. The single degree-of-freedom
model can express the high-frequency spectra of Noyes' model. The pathological tooth is characterised by a longer damped time
constant and a larger acceleration maximum. This impact response method can effectively be applied to clinical diagnosis in
view of the physical parameters and mechanical elements which have been derived. 相似文献
58.
目的:探讨背根神经节(DRG)内P物质(SP)、降钙素基因相关肽(CGRP)免疫阳性神经元与阴茎包皮系带感觉信息传递之问的关系。方法:通过荧光金(FG)逆行标记对大鼠阴茎包皮系带内神经末梢的来源作追踪定位,并结合SP、CGRP免疫荧光标记法,研究大鼠DRG内FG标记阳性神经元中SP、CGRP免疫阳性神经元的形态和分布。结果:FG逆行标记结果发现,大鼠阴茎包皮系带内的神经末梢起源于第6腰髓对应的背根神经节(L6-DRG)和第1骶髓对应的背根神经节(S1-DRG)的神经元。对这些神经元分别作SP、CGRP免疫荧光标记后发现,标记细胞大小不等,分别呈深红色和深绿色,沿神经束成行排列或散在分布。FG/SP、FG/CGRP双标记阳性细胞均为中小型,其数量分别占FG逆行标记阳性细胞总数的1/3和1/2,FG/SP/CGRP三标记阳性细胞占FG逆行标记阳性细胞总数的1/5。结论:大鼠L6-DRG和S1-DRG内的SP、CGRP免疫阳性神经元可能参与阴茎包皮系带感觉信息的传递。 相似文献
59.
Mohammed AL-JUMAILY Alexei KOZLENKOV Ilana MECHALY Agnes FICHARD Valerie MATHA Frederique SCAMPS Jean VALMIER Patrick CARROLL 《中国神经科学杂志》2007,(5)
目的在背根神经节(dorsal root ganglion,DRG)中等大小感觉神经元中可以观察到钙激活氯离子流(I_(Cl(Ca)))。在坐骨神经损伤模型中,在大多数大中神经元上诱导出类似的氯离子流。本文旨在探讨引起这个离子流的分子基础。方法使用常规的定量RT-PCR方法检测在DRG中三个基因家族的表达,这三个基因家族都具有诱导I_(Cl(Ca))的特点。结果在成年小鼠的DRG中,分别显示了在正常状态和坐骨神经损伤3天后CLCA,Bestrophin和Tweety基因家族成员的转录产物。结论mBestl和Tweety2可能在损伤诱导的DRG神经元I_(Cl(Ca))中发挥作用。 相似文献
60.
Bradley J Katz John R Burroughs Richard L Anderson Shannon Bownds John D McCann 《Movement disorders》2007,22(2):231-234
We present a patient with a facial movement disorder that has characteristics of both blepharospasm and bilateral asynchronous hemifacial spasm. Because of the increased incidence of blepharospasm in patients with hemifacial spasm, our patient's clinical presentation is probably not a chance occurrence, but rather a manifestation of some predisposition for these two movement disorders. This unusual constellation of signs and symptoms challenges the current diagnostic criteria and suggests that some of these facial movement disorders may lie on a spectrum, rather than represent distinct entities. 相似文献