全文获取类型
收费全文 | 14405篇 |
免费 | 881篇 |
国内免费 | 518篇 |
专业分类
耳鼻咽喉 | 277篇 |
儿科学 | 84篇 |
妇产科学 | 12篇 |
基础医学 | 2689篇 |
口腔科学 | 271篇 |
临床医学 | 1015篇 |
内科学 | 405篇 |
皮肤病学 | 50篇 |
神经病学 | 6272篇 |
特种医学 | 200篇 |
外科学 | 544篇 |
综合类 | 1629篇 |
现状与发展 | 2篇 |
预防医学 | 128篇 |
眼科学 | 1016篇 |
药学 | 790篇 |
1篇 | |
中国医学 | 342篇 |
肿瘤学 | 77篇 |
出版年
2024年 | 24篇 |
2023年 | 123篇 |
2022年 | 173篇 |
2021年 | 365篇 |
2020年 | 317篇 |
2019年 | 312篇 |
2018年 | 296篇 |
2017年 | 332篇 |
2016年 | 373篇 |
2015年 | 300篇 |
2014年 | 517篇 |
2013年 | 571篇 |
2012年 | 639篇 |
2011年 | 666篇 |
2010年 | 699篇 |
2009年 | 624篇 |
2008年 | 676篇 |
2007年 | 679篇 |
2006年 | 736篇 |
2005年 | 564篇 |
2004年 | 522篇 |
2003年 | 562篇 |
2002年 | 452篇 |
2001年 | 369篇 |
2000年 | 319篇 |
1999年 | 311篇 |
1998年 | 345篇 |
1997年 | 332篇 |
1996年 | 233篇 |
1995年 | 269篇 |
1994年 | 248篇 |
1993年 | 227篇 |
1992年 | 203篇 |
1991年 | 223篇 |
1990年 | 178篇 |
1989年 | 179篇 |
1988年 | 171篇 |
1987年 | 178篇 |
1986年 | 297篇 |
1985年 | 321篇 |
1984年 | 187篇 |
1983年 | 159篇 |
1982年 | 143篇 |
1981年 | 149篇 |
1980年 | 117篇 |
1979年 | 37篇 |
1978年 | 28篇 |
1977年 | 18篇 |
1976年 | 19篇 |
1974年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 583 毫秒
1.
《Neuromodulation》2021,24(8):1422-1428
ObjectivesA recent approach to treatment of cluster headaches (CH) employs a microstimulator device for on-demand neuromodulation of the sphenopalatine ganglion (SPG) during an acute CH attack. A precise anatomical localization of the SPG within the pterygopalatine fossa (PPF) is optimal in order to position the SPG electrode array. This study aims to investigate a novel approach for SPG localization using computed tomography angiographic studies (CTA).Materials and MethodsTwo independent observers identified the location of the SPG on 54 computed tomography angiographic studies (CTA) and measured its position relative to the vidian canal (VC). The qualitative confidence of identification, morphology, position within the PPF and its relation to vascular structures were also recorded.ResultsThe SPG was detectable in 88% of cases with a variable position. The most frequent positions were superior (56%) and lateral (99%) relative to the VC with a mean (±SD) craniocaudal distance of 0.34 mm (±1.38) and a mean mediolateral distance of 3.04 mm (±1.2). However, in a considerable proportion of cases, the SPG was identified inferiorly to the VC (33%). Interobserver and intraobserver agreement for SPG location were moderate and strong respectively.ConclusionsSince localization of SPG on CTAs is feasible and reproducible, it has future clinical potential to aid placement, optimal positioning and individualized programming of the electrode array. 相似文献
2.
目的观察丙泊酚麻醉对老龄大鼠认知功能及海马神经元γ-氨基丁酸A(GABA)受体表达的影响。方法50只SD老年大鼠随机分为丙泊酚组和对照组,每组25只。丙泊酚组大鼠腹腔注射1%丙泊酚中/长链脂肪乳注射液6 mL/kg,对照组腹腔注射等体积的生理盐水。麻醉后1 d进行Morris水迷宫实验,分别采用HE染色和尼氏体染色观察海马区神经细胞及尼氏体(Nissl体)形态学变化,Western Blot检测GABA蛋白量表达。结果麻醉后,2组大鼠肛温、心率、呼吸频率、血氧饱和度比较,差异均无统计学意义(P>0.05)。随着实验时间的延长,2组大鼠逃逸潜伏期、总里程数逐渐减小,丙泊酚组大鼠各时间点逃逸潜伏期、总里程均高于对照组,差异有统计学意义(P<0.05)。丙泊酚组大鼠穿越平台区域次数、时间小于、短于对照组,差异有统计学意义(P<0.05)。对照组海马区Nissl体存在于细胞浆及树突,染色较深,神经细胞排列整齐,形态规则;丙泊酚组Nissl体消失,神经细胞数量减少,细胞核破裂、丢失。丙泊酚组大鼠海马GABA蛋白表达量低于对照组,差异有统计学意义(P<0.05)。结论丙泊酚对大鼠认知功能有影响,并与海马区GABA的表达相关。 相似文献
3.
4.
Yuanqing Yao Jun Qian Shunkang Rong Yuwen Huang Bo Xiong Gang Yang Dengqing Zhang Shimin Deng Jie Tan Que Zhu Changming Deng Dichuan Liu Haitao Ran Zhigang Wang Jing Huang 《Ultrasound in medicine & biology》2019,45(2):490-499
Stellate ganglion (SG) modification has been investigated for arrhythmia treatment. In this study, transesophageal SG imaging and intervention were explored using a homemade 30F integrated focused ultrasonic catheter in healthy mongrel canines in vivo. Anatomic details of SGs were ultrasonically imaged and evaluated. SG had a heterogeneous echoic structure and characteristic profiles sketched by hyper-echoic outlines in an ultrasonogram. Left SGs in the experimental group were successfully ablated through the esophagus under ultrasonic guidance provided by the catheter itself. Two weeks after the ablation, the QT and QTc of the experimental group decreased compared with those of the sham group and at baseline (both p values < 0.001). Histologic examination revealed that left SGs were destroyed. No major complications were observed. This approach may be further explored as a method for ganglia remodeling evaluation and as a strategy of ganglia modification for arrhythmia and for other diseases. 相似文献
5.
原发性三叉神经痛是三叉神经分布区内短暂的发作性剧痛,多发于中老年人,40岁以上患者占70%~80%,发作时表现为面颊上下颌及舌部明显的剧烈电击样、针刺样、刀割样疼痛,持续时间短,突发突止,间歇期完全正常。中医将其归属于"面痛"范畴,多从风热立论,笔者跟随导师临证过程中,发现《医宗金鉴》的芎芷石膏汤治疗风热上犯型原发性三叉神经痛效果显著。 相似文献
6.
7.
8.
Hiroki Toyoda 《Synapse (New York, N.Y.)》2019,73(7)
The insular cortex plays essential roles in nicotine addiction. However, much is still unknown about its cellular and synaptic mechanisms responsible for nicotine addiction. We have previously shown that in layer 5 pyramidal neurons of the mouse insular cortex, activation of the nicotinic acetylcholine receptors (nAChRs) suppresses synaptic potentiation through enhancing GABAergic synaptic transmission, although it enhances both glutamatergic and GABAergic synaptic transmission. In the present study, we examined whether dopamine receptors might contribute to the nicotine‐induced inhibition of synaptic potentiation. The nicotine‐induced inhibition of synaptic potentiation was decreased in the presence of a D1 dopamine receptor antagonist SCH23390 irrespective of the presence of a D2 dopamine receptor antagonist sulpiride, suggesting that D1 dopamine receptors are involved in nicotine‐induced inhibition. We also investigated how dopamine receptors might contribute to the nAChR‐induced enhancement of glutamatergic and GABAergic synaptic transmission. The nAChR‐induced enhancement of GABAergic synaptic transmission was decreased in the presence of SCH23390 irrespective of the presence of sulpiride, whereas that of glutamatergic synaptic transmission was not altered in the presence of SCH23390 and sulpiride. These results suggest that D1 dopamine receptors are involved in the nAChR‐induced enhancement of GABAergic synaptic transmission while dopamine receptors are not involved in that of glutamatergic synaptic transmission. These observations indicate that the interaction between nAChRs and D1 dopamine receptors plays critical roles in synaptic activities in layer 5 pyramidal neurons of the mouse insular cortex. These insular synaptic changes might be associated with nicotine addiction. 相似文献
9.
Amyotrophic lateral sclerosis is a fatal neurodegenerative disorder characterized by upper and lower motor neuron degeneration, which leads to progressive paralysis of skeletal muscles and, ultimately, respiratory failure between 2–5 years after symptom onset. Unfortunately, currently accepted treatments for amyotrophic lateral sclerosis are extremely scarce and only provide modest benefit. As a consequence, a great effort is being done by the scientific community in order to achieve a better understanding of the different molecular and cellular processes that influence the progression and/or outcome of this neuropathological condition and, therefore, unravel new potential targets for therapeutic intervention. Interestingly, a growing number of experimental evidences have recently shown that, besides its well-known physiological roles in the developing and adult central nervous system, the Wnt family of proteins is involved in different neuropathologica conditions, including amyotrophic lateral sclerosis. These proteins are able to modulate, at least, three different signaling pathways, usually known as canonical(β-catenin dependent) and non-canonical(β-catenin independent) signaling pathways. In the present review, we aim to provide a general overview of the current knowledge that supports the relationship between the Wnt family of proteins and its associated signaling pathways and amyotrophic lateral sclerosis pathology, as well as their possible mechanisms of action. Altogether, the currently available knowledge suggests that Wnt signaling modulation might be a promising therapeutic approach to ameliorate the histopathological and functional deficits associated to amyotrophic lateral sclerosis, and thus improve the progression and outcome of this neuropathology. 相似文献
10.
Bi-Hua BIE Yong CHEN Zhi-Qi ZHAO Institute of Neurobiology Fu-Dan University Shanghai China Institute of Shanghai Physiology Chinese Academy of Sciences Shanghai China 《中国神经科学杂志》2006,(2)
Objective Ligustrazine, also named as tetramethylpyrazine, is a compound purified from Ligusticum chuanxiong hort and has ever been testified to be a calcium antagonist. The present investigation was to determine the antinoci-ceptive effect of ligustrazine and, if any, the peripheral ionic mechanism involved. Methods Paw withdrawal Latency ( PWL) to noxious heating was measured in vivo and whole-cell patch recording was performed on small dorsal root ganglion (DRG) neurons. Results Intraplantar injection of ligustrazine (0.5 mg in 25μl) significantly prolonged the withdrawal latency of ipsilateral hindpaw to noxious heating in the rat. Ligustrazine not only reversibly inhibited high-voltage gated calcium current of dorsal root ganglion (DRG) neuron in dose-dependent manner with IC50 of 1.89 mmol/L, but also decreased tetrodotoxin (TTX) -resistant sodium current in relatively selective and dose-dependent manner with IC50 of 2.49 mmol/L. Conclusion The results suggested that ligustrazine could elevate the threshold of thermal nociception through inhibiting the high-voltage gated calcium current and TTX-resistant sodium current of DRG neuron in the rat. 相似文献