全文获取类型
收费全文 | 2443篇 |
免费 | 81篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 579篇 |
儿科学 | 24篇 |
妇产科学 | 18篇 |
基础医学 | 284篇 |
口腔科学 | 38篇 |
临床医学 | 513篇 |
内科学 | 183篇 |
皮肤病学 | 3篇 |
神经病学 | 235篇 |
特种医学 | 96篇 |
外科学 | 130篇 |
综合类 | 198篇 |
预防医学 | 42篇 |
眼科学 | 6篇 |
药学 | 152篇 |
中国医学 | 8篇 |
肿瘤学 | 58篇 |
出版年
2023年 | 19篇 |
2022年 | 28篇 |
2021年 | 35篇 |
2020年 | 38篇 |
2019年 | 57篇 |
2018年 | 59篇 |
2017年 | 56篇 |
2016年 | 50篇 |
2015年 | 73篇 |
2014年 | 133篇 |
2013年 | 183篇 |
2012年 | 110篇 |
2011年 | 126篇 |
2010年 | 92篇 |
2009年 | 117篇 |
2008年 | 118篇 |
2007年 | 105篇 |
2006年 | 106篇 |
2005年 | 77篇 |
2004年 | 79篇 |
2003年 | 78篇 |
2002年 | 60篇 |
2001年 | 64篇 |
2000年 | 74篇 |
1999年 | 65篇 |
1998年 | 43篇 |
1997年 | 55篇 |
1996年 | 35篇 |
1995年 | 40篇 |
1994年 | 39篇 |
1993年 | 33篇 |
1992年 | 26篇 |
1991年 | 23篇 |
1990年 | 28篇 |
1989年 | 29篇 |
1988年 | 26篇 |
1987年 | 12篇 |
1986年 | 18篇 |
1985年 | 19篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 9篇 |
1981年 | 17篇 |
1980年 | 12篇 |
1979年 | 19篇 |
1978年 | 22篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1973年 | 3篇 |
排序方式: 共有2567条查询结果,搜索用时 15 毫秒
1.
Anastasiia Panfilova Sarah E. Shelton Cristina Caresio Ruud J.G. van Sloun Filippo Molinari Hessel Wijkstra Paul A. Dayton Massimo Mischi 《Ultrasound in medicine & biology》2019,45(2):539-548
Dynamic contrast-enhanced ultrasound (DCE-US) has been proposed as a powerful tool for cancer diagnosis by estimation of perfusion and dispersion parameters reflecting angiogenic vascular changes. This work was aimed at identifying which vascular features are reflected by the estimated perfusion and dispersion parameters through comparison with acoustic angiography (AA). AA is a high-resolution technique that allows quantification of vascular morphology. Three-dimensional AA and 2-D DCE-US bolus acquisitions were used to monitor the growth of fibrosarcoma tumors in nine rats. AA-derived vascular properties were analyzed along with DCE-US perfusion and dispersion to investigate the differences between tumor and control and their evolution in time. AA-derived microvascular density and DCE-US perfusion exhibited good agreement, confirmed by their spatial distributions. No vascular feature was correlated with dispersion. Yet, dispersion provided better cancer classification than perfusion. We therefore hypothesize that dispersion characterizes vessels that are smaller than those visible with AA. 相似文献
2.
目的:评价耳蜗神经电位活动直接监护在听神经瘤手术中对保护听力的作用。方法:听神经瘤手术中施行耳蜗电图监护。结果:16例听神经瘤手术中施行耳蜗电图监护者,术后听力保留5例(31%),其中4例为有效听力保留。肿瘤在2厘米以下者听力保留为38%(5/13)。结论:听神经瘤手术过程中采用耳蜗电图监护,能敏感地反应即时的听神经功能状况,给术者及时的反馈信息,有助于听力保护 相似文献
3.
胎儿声振动刺激反应的研究 总被引:5,自引:0,他引:5
目的:了解不同孕龄胎儿对声振动刺激的反应。方法:对435例次正常中、晚期妊娠妇女进行声振胎心试验(VAS-T)、声振胎动试验(SPFM),并对声振动刺激前、后胎心率变化规律进行前瞻性研究。结果:(1)从24周开始,胎儿对声振刺激有反应,但大部分未能达到VAS-T诊断标准,而胎动反应良好。(2)妊娠28周开始,声振刺激后,90%以上的胎儿出现显著的胎动、胎心率加速反应,足月胎儿反应率在98%以上。(3)SPFM阳性率的显著提高早于VAS-T。提示:28周后胎儿神经系统发育已趋完善。胎儿运动神经的发育成熟早于植物神经。 相似文献
4.
J. Pepke-Zaba T. W. Higenbottam A. T. Dinh Xuan J. P. Scott T. A. H. English J. Wallwork 《Transplant international》1990,3(1):108-112
Abstract. Twenty-one patients were studied at rest and during exercise after heart transplantation to compare cardiac output measured by thermodilution and impedance cardiography. Exercise was performed on a bicycle ergometer over a limited range of work load (25 and 50 watt) whilst metabolic gas exchange was recorded. One patient was studied at rest whilst his circulation was maintained by a Jarvik-7 artificial heart. The values of cardiac output measured by impedance cardiography corresponded closely with the flow rate from the artificial heart. There was also close agreement between the impedance and thermodilution measurements of cardiac output at rest and during exercise. Both measurements followed the changes in heart rate and oxygen consumption. Both thermodilution and impedance cardiography methods elicited good reproducibility of cardiac output measurements at rest and during exercise. These observations suggest that the noninvasive and continuous record of cardiac output obtained by impedance cardiography can be used for the postoperative monitoring of heart transplant recipients. 相似文献
5.
Tilman Keck Kerstin Wiesmiller Joerg Lindemann Ajnacska Rozsasi 《European archives of oto-rhino-laryngology》2006,263(10):910-916
Acoustic rhinometry is one method to evaluate nasal geometry by an acoustic reflection technique. The aim of this study was to investigate the changes in acoustic rhinometry after nasal provocation in patients with exclusively perennial allergic rhinitis. In 19 patients, acoustic rhinometry and active anterior rhinomanometry were performed before and after nasal provocation test. There was a statistically significant nasal flow reduction measured by active anterior rhinomanometry after nasal provocation (p < 0.05) and a median symptom score of four points, both indicating a positive response to nasal provocation. On the other hand, there was no statistically significant change in the values of acoustic rhinometry after nasal provocation (p > 0.05). In patients with exclusively perennial allergic rhinitis, acoustic rhinometry does not seem to significantly change after nasal provocation. In contrast, active anterior rhinomanometry values decreased significantly after nasal provocation. The presented results indicate that acoustic rhinometry does not seem to be a diagnostic method superior to active anterior rhinomanometry in this context. 相似文献
6.
目的评价螺内酯联合依那普利治疗老年人扩张型心肌病(DCM)心力衰竭的有效性和安全性。方法以148例老年DCM心力衰竭患者作研究对象,按随机化原则分为观察组(74例)和对照组(74例)。对照组为依那普利,加上基础用药(地高辛、双氢克尿噻);观察组为对照组用药加上螺内酯。治疗6周后复查两组的动态心电图、超声心动图。结果治疗后两组的左室射血分数(LVEF)均有增加,左室收缩末期容积(LVESV)和左室舒张末期容积(LVEDV)均有减少,24 h室性早搏(VA)数也均有减少;观察组与对照组比较,LVEF显著增加。两组均未发现高血钾及肝肾功能损害。结论在老年DCM心力衰竭常规用药的基础上,常规加用螺内酯联合依那普利的治疗有效、安全,可显著改善左室重构和防治猝死。 相似文献
7.
为选择中等场强的MRI听神经瘤成像最佳序列。收集手术和病理证实的听神经瘤135例,分析序列Ⅰ、Ⅱ对内听道中心层面、三叉神经显示率及MR征象的显示情况。结果:序列I择内听道中心层面及三叉神经的显示均优于序列Ⅱ,序列Ⅱ在显示肿瘤内囊变、出血、不肿优于序列I;对肿瘤钙化、肿瘤血管、脑干移位的观察,两者相仿。结果显示:序列I在中等场经下作为听神经瘤成像的首选序列,并中运用到小脑角区MRI成像。 相似文献
8.
为探讨左心室造影功能成像的价值与限度,我们选择冠脉及左心室造影者38例行左室功能成像,观察左室壁运动情况并与节段法室壁运动定量分析比较。结果示左室收缩正常18例,其各节段EF值平均39%,节段性收缩减弱7例,无收缩3例,矛盾收缩4例,普遍性收缩减弱6例,病变节段的EF值平均5~19%,明显低于正常者(P<0.01)。结论:左室功能成像效果直观且客观,可作为室壁运动定量分析的一个重要补充。 相似文献
9.
Amphetamine-induced mesolimbic dopamine release has been reported to reduce prepulse inhibition of the acoustic startle response. In addition, it is well known that mesolimbic dopamine stimulation leads to hyperactivity. The present study was undertaken to explore the possibility that one or the other measure may be a more sensitive in vivo indicator of dopamine release in the nucleus accumbens by determining if the amphetamine dose-response curves for these two behavioral measures were different. The data indicate that the dose-response curves obtained for the different behavioral measures are identical. These data are consistent with the idea that the same dopamine terminal field supports both prepulse inhibition of the acoustic startle response and dopamine-stimulated hyperactivity. 相似文献
10.
回顾分析了20例22个听神经瘤的MRI表现。MRI检查采用0.35T超导MT/S成像系统,常规行冠状面T_1加权及横断面T_(1-)T_2加权成像。据瘤体大小将病灶分成4组,包括限于内听道者1例,1-2cm者2例,2.1-3cm者8例,大于3cm者11例,结果表明,T_1加权像对听神经瘤的诊断价值较大,主要依据是CP角内出现与听神经根部相连的肿块或听神经明显增粗;大于2cm的听神经瘤多可发生囊变、出血及脑干、Ⅳ脑室受压。除可发现位于内听道内的微小肿瘤外,MRI在肿瘤囊变、出血、周围结构受压情况、肿瘤供血血管及肿瘤与周围粘连情况的显示上均具有一定的优越性。 相似文献