全文获取类型
收费全文 | 10197篇 |
免费 | 654篇 |
国内免费 | 294篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 160篇 |
妇产科学 | 214篇 |
基础医学 | 765篇 |
口腔科学 | 790篇 |
临床医学 | 890篇 |
内科学 | 1786篇 |
皮肤病学 | 88篇 |
神经病学 | 1153篇 |
特种医学 | 610篇 |
外科学 | 983篇 |
综合类 | 1121篇 |
现状与发展 | 1篇 |
预防医学 | 234篇 |
眼科学 | 1306篇 |
药学 | 455篇 |
中国医学 | 217篇 |
肿瘤学 | 255篇 |
出版年
2024年 | 20篇 |
2023年 | 184篇 |
2022年 | 329篇 |
2021年 | 473篇 |
2020年 | 412篇 |
2019年 | 387篇 |
2018年 | 371篇 |
2017年 | 305篇 |
2016年 | 325篇 |
2015年 | 353篇 |
2014年 | 591篇 |
2013年 | 637篇 |
2012年 | 465篇 |
2011年 | 562篇 |
2010年 | 494篇 |
2009年 | 485篇 |
2008年 | 467篇 |
2007年 | 448篇 |
2006年 | 433篇 |
2005年 | 346篇 |
2004年 | 300篇 |
2003年 | 276篇 |
2002年 | 195篇 |
2001年 | 190篇 |
2000年 | 166篇 |
1999年 | 170篇 |
1998年 | 175篇 |
1997年 | 156篇 |
1996年 | 118篇 |
1995年 | 126篇 |
1994年 | 115篇 |
1993年 | 107篇 |
1992年 | 84篇 |
1991年 | 80篇 |
1990年 | 68篇 |
1989年 | 71篇 |
1988年 | 55篇 |
1987年 | 57篇 |
1986年 | 54篇 |
1985年 | 64篇 |
1984年 | 75篇 |
1983年 | 39篇 |
1982年 | 65篇 |
1981年 | 55篇 |
1980年 | 47篇 |
1979年 | 30篇 |
1978年 | 35篇 |
1977年 | 22篇 |
1976年 | 18篇 |
1975年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
目的建立重庆市正常牙合青少年牙颌模型牙列指数的正常值,为正畸临床提供依据.方法选取重庆市正常牙合青少年牙颌模型92付(男45付,女47付),测量牙冠宽度、牙弓宽度,计算Bolton指数和Pont指数,对测量结果进行统计分析并与国内外相关资料进行对比研究,对Bolton指数和Pont指数的临床应用价值进行评价.结果Bolton指数和Pont指数存在种族和地区差异,结论Bolton指数和Pont指数在正畸临床中均有一定的应用价值,临床上应参照本民族和地区的标准. 相似文献
22.
We present a patient with vertebrobasilar insufficiency, with vertigo and horizontal nystagmus, induced by turning the head to the right. Angiography demonstrated transient occlusion of the left vertebral artery at the atlantoaxial joint during rotation of the head. The pathogenesis and angiographic findings are discussed. 相似文献
23.
The purpose of the present study was to determine the reliability of several selected signs of trauma from occlusion and their relations with severity of periodontitis. 32 moderate to advanced chronic periodontitis patients participated in the study. All teeth present were evaluated for various abnormal occlusal contacts, signs of trauma from occlusion, and the severity of periodontitis. Standardized periapical radiographs were also taken for each tooth. The results demonstrated that: (1) no significant difference occurred in probing pocket depth (PD), clinical attachment loss (AL), or percentage of alveolar bone height (BH) between teeth with and without various abnormal occlusal contacts, i.e., premature contacts in centric relation occlusion, non-working contacts in lateral excursions, premature contacts of anterior teeth or posterior protrusive tooth contacts; (2) teeth with either significant mobility, functional mobility, or radiographically widened periodontal ligament space (PDLS) had deeper PD, more AL and lower BH than teeth without these signs, while teeth with pronounced wear or radiographically thickened lamina dura had less AL than teeth without these findings; (3) 2 combined indices, i.e., the trauma from occlusion index (TOI) and the adaptability index (AI), were proposed for the identification of occlusal trauma and the response of periodontium to excessive biting forces in heavy function, respectively; TOI-positive teeth exhibit deeper PD, more AL and less osseous support than TOI-negative teeth; however, AI-positive teeth had less AL and more osseous support than AI-negative teeth; (4) with identical attachment level, TOI-positive teeth had less osseous support than TOI-negative teeth while the magnitude of difference became greater with an increase of attachment loss. 相似文献
24.
Acute occlusion of the left main coronary artery is normally fatal. According to the literature, only a few cases have been treated by intracoronary thrombolysis; the prolonged period of ischemia, however, resulted in severe left ventricular dysfunction and numerous complications. Therefore, effort should be directed to recanalize the left main coronary artery within the shortest possible interval. We followed this approach in a case of acute occlusion of a subtotal stenosis of the left main coronary artery which could be mechanically reopened and dilated within a few minutes. The intervention resulted in immediate reversal of profound cardiogenic shock and complete restoration of normal left ventricular function. At hospital discharge, the patient was asymptomatic with a negative bicycle stress test. Immediate mechanical recanalization and angioplasty appear to be a feasible approach in life-threatening coronary occlusion. 相似文献
25.
50例正常生育力男子精液和血液激素的一年动态观察 总被引:5,自引:0,他引:5
作者对南京市50名正常男子,每月1次、连续12个月测定了精液常规、某些精液生化和血清激素水平。结果表明:精子密度每次之间波动范围较大,冬季数值比夏季显著为高(P<0.01)。其它指标包括正常形态精子、活动精子、前向运动级别、精液果糖、硷性磷酸酶、酸性磷酸酶及血清,FSH LH T 则变动不显著。精液常规中除精子密度和各参数关系不明显外,所有其它参数之间呈正相关;但精液常规、精液生化和血清激素三者互不相关。从本组研究结果,作者提出了南京市正常男子这些指标的参考正常值。 相似文献
26.
Pui-Yin Lee Wai-Hong Chen William Ng Chu-Pak Lau 《Catheterization and cardiovascular interventions》2003,60(4):558-561
Subclavian artery lesion that is associated with low complication rate could be treated by percutaneous intervention effectively. However, the success of endovascular therapy for occlusive lesion may be limited by failure to cross with a guidewire. We describe the use of a system using optical coherence reflectometry for navigation and radiofrequency ablation to enable wire passage through subclavian artery occlusion that could not be crossed by conventional guidewires. 相似文献
27.
人皮质骨矿化基质中骨盐框架结构 总被引:2,自引:0,他引:2
目的:研究人皮质骨矿化基质中骨盐的框架结构及框架中骨微间隙。方法:应用透射电镜、场发射扫描电镜观察、电脑图像分析及能谱分析,分析无骨病成人长骨、扁骨200例骨盐分布特征。结果:骨盐框架结构由微柱、微梁、微小梁、弓状梁、致密点、隔板和骨微间隙构成。骨微间隙由洞、内衬和壁组成,洞平均直径为84.4±75.6nm,与骨小管相比有显著差异(P值<0.001),平均密度为11~17个/μm2,与骨小管之比超过10:1。骨盐分针形结晶和微颗粒结晶。结论:骨盐框架结构及骨微间隙是骨盐在人皮质骨矿化基质中的存在形式,可能与骨盐吸收、沉着有关。 相似文献
28.
Henryk Barthel Michael Wiener Claudia Dannenberg Simone Bettin Bernhard Sattler Wolfram H. Knapp 《European journal of nuclear medicine and molecular imaging》1997,24(10):1245-1252
This study addresses the question of whether the normal range for distribution of local cerebral blood flow (lCBF) in adults
can be transferred to the 4- to 15-year-old age group. Twenty-three children (age: 4–15 years; mean 11±3 years, group I) and
10 adults (age: 27–56 years; mean 45±10 years, group II) without evidence of cerebrovascular disease or other brain diseases
underwent technetium-99m ethyl cysteinate dimer single-photon emission tomography. Counts in cortical and subcortical regions
of interest (ROIs) were related to those in cerebellar ROIs (= 100%). Relative cortical activity in group I exceeded that
in group II, particularly in left parietal (107.6%±9.8% vs 84.1%±12.4%), left frontal (97.7%±6.7% vs 79.4%±8.9%) and left
temporal areas (99.7%±7.4% vs 84.9%±10.1%) and in the cingulate cortex (112.1%±9.1% vs 95.9%±10.1%, P<0.05). Cerebral activity uptake per injected dose was inversely correlated with age in 19 children of group I (r = –0.77, P<0.001). In group I, there was also an inverse correlation between age and the relative local count density in the parietal
(r = –0.42 to –0.57), frontal (r = –0.48), temporal (r = –0.42 to –0.58) and occipital cortex (r = –0.44). In these cortical regions relative counts differed when subgroups of children aged 4–10 and 11–15 years were analysed.
It is concluded that there are systematic differences between 4- to 15-year-old children and adults with regard to normal
lCBF. Diagnostic use of perfusion agents has to consider age-adjusted normal flow maps; normal ranges should be determined
separately for the age groups 4–10 and 11–15 years.
Received 23 March and in revised form 11 July 1997 相似文献
29.
A. Larsson Ch. Jensen M. Bilting S. Ekholm H. Stephensen C. Wikkelsö 《Acta neurochirurgica》1992,117(1-2):15-22
Summary Thirteen patients with normal pressure hydrocephalus were operated upon with an externally manoeuvrable shunt system (Sophy SU8) in order to investigate its influence on clinical outcome, intracranial pressure and cranial CT parameters. The opening pressure was set at high at surgery and lowered stepwise at intervals of three months to medium and low. The clinical condition, intracranial pressure and cranial CT parameters were examined at the end of the 3 months interval on each pressure level.The patients improved within the first 3 months inspite of an unchanged mean intracranial pressure and remained in a stable clinical condition during the rest of the study period. The intracranial pressure was significantly reduced at 9 months. The ventricular index, Evans index, temporal horn and third ventricle width were reduced 3 months post-operatively and did not change significantly during the rest of the study. The pre-operative third ventricle width was correlated to high psychometric test results after shunt surgery. Reduction in ventricular index, Evans index and third ventricle width after surgery correlated to improvement in psychometric scoring.The clinical improvement after shunt surgery for normal pressure hydrocephalus is seen within 3 months and is independent of the adjusted valve pressure. 相似文献
30.
Horst J. Jaeger Klaus D. Mathias Udo Kempkes 《Cardiovascular and interventional radiology》1994,17(6):328-332
A 66-year-old man presented with bilateral subclavian steal syndrome (SSS) due to proximal subclavian artery occlusions. He was treated by percutaneous transluminal balloon angioplasty (PTA) and stent implantation in the left subclavian artery and by PTA alone in the right subclavian artery. We could demonstrate that interventional treatment of symptomatic bilateral SSS is possible. If PTA alone is insufficient, stent implantation should be considered. 相似文献