首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   25635篇
  免费   2070篇
  国内免费   594篇
耳鼻咽喉   112篇
儿科学   741篇
妇产科学   289篇
基础医学   1409篇
口腔科学   192篇
临床医学   5208篇
内科学   5094篇
皮肤病学   195篇
神经病学   2367篇
特种医学   1549篇
外国民族医学   1篇
外科学   4089篇
综合类   3201篇
现状与发展   4篇
预防医学   781篇
眼科学   403篇
药学   1444篇
  23篇
中国医学   509篇
肿瘤学   688篇
  2024年   107篇
  2023年   639篇
  2022年   1072篇
  2021年   1329篇
  2020年   1265篇
  2019年   1107篇
  2018年   972篇
  2017年   984篇
  2016年   909篇
  2015年   939篇
  2014年   1692篇
  2013年   1807篇
  2012年   1440篇
  2011年   1507篇
  2010年   1251篇
  2009年   1193篇
  2008年   1178篇
  2007年   1087篇
  2006年   1051篇
  2005年   902篇
  2004年   722篇
  2003年   677篇
  2002年   529篇
  2001年   450篇
  2000年   361篇
  1999年   286篇
  1998年   303篇
  1997年   304篇
  1996年   236篇
  1995年   240篇
  1994年   196篇
  1993年   163篇
  1992年   175篇
  1991年   131篇
  1990年   127篇
  1989年   119篇
  1988年   114篇
  1987年   76篇
  1986年   92篇
  1985年   121篇
  1984年   92篇
  1983年   51篇
  1982年   71篇
  1981年   55篇
  1980年   40篇
  1979年   37篇
  1978年   22篇
  1977年   25篇
  1976年   20篇
  1975年   10篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
Behavioral disturbances have been reported with subthalamic (STN) deep brain stimulation (DBS) treatment in Parkinson's disease (PD). We report correlative functional imaging (fMRI) of mood and motor responses induced by successive right and left DBS. A 36-year-old woman with medically refractory PD and a history of clinically remitted depression underwent uncomplicated implantation of bilateral STN DBS. High-frequency stimulation of the left electrode improved motor symptoms. Unexpectedly, right DBS alone elicited several reproducible episodes of acute depressive dysphoria. Structural and functional magnetic resonance imaging (fMRI) imaging was carried out with sequential individual electrode stimulation. The electrode on the left was within the inferior STN, whereas the right electrode was marginally superior and lateral to the intended STN target within the Fields of Forel/zona incerta. fMRI image analysis (Analysis of Functional NeuroImages, AFNI) contrasting OFF versus ON stimulation identified significant lateralized blood oxygen level-dependent (BOLD) signal changes with DBS (P < 0.001). Left DBS primarily showed changes in motor regions: increases in premotor and motor cortex, ventrolateral thalamus, putamen, and cerebellum as well as decreases in sensorimotor/supplementary motor cortex. Right DBS showed similar but less extensive change in motor regions. More prominent were the unique increases in superior prefrontal cortex, anterior cingulate (Brodmann's area [BA] 24), anterior thalamus, caudate, and brainstem, and marked widespread decreases in medial prefrontal cortex (BA 9/10). The mood disturbance resolved spontaneously in 4 weeks despite identical stimulation parameters. Transient depressive mood induced by subcortical DBS stimulation was correlated with changes in mesolimbic cortical structures. This case provides new evidence supporting cortical segregation of motor and nonmotor cortico-basal ganglionic systems that may converge in close proximity at the level of the STN and the adjacent white matter tracts (Fields of Forel/zona incerta).  相似文献   
72.
High-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves the motor symptoms of Parkinson's disease (PD). Opposite changes in mood, such as mania or depression, have been reported after surgery, but it is not known whether these side effects are specifically related to STN DBS. To learn whether STN DBS also influences the limbic loop, we investigated acute subjective psychotropic effects related to levodopa or bilateral STN DBS. After a median postoperative follow-up of 12 months, 50 PD patients completed the Addiction Research Center Inventory (ARCI), assessing subjective psychotropic effects in four conditions: off-drug/on-stimulation; off-drug/off-stimulation; on-drug/off-stimulation; and on-drug/on-stimulation. Both levodopa and STN DBS improved all the ARCI subscales, indicating subjective feelings of well being, euphoria, increase in motivation, and decrease in fatigue, anxiety, and tension. A suprathreshold dose of levodopa was significantly more effective than STN DBS, using the same electrical parameters as for chronic stimulation, on four of the five ARCI subscales. We concluded that 1) both STN DBS and levodopa have synergistic acute beneficial psychotropic effects in PD, 2) the psychotropic effects of both treatments need to be considered in the long-term management of chronic STN DBS, and 3) the results indicate an involvement of the limbic STN in mood disorders of PD.  相似文献   
73.
丹参、藻酸双酯钠是临床治疗脑血管病的常用药。本研究发现,在体外流场中用丹参、藻酸双酯钠分别处理脑血栓形成病人的红细胞后,此红细胞与培养的人脉静脉内皮细胞的粘附数目明显减少、粘附强度明显减弱;而且,在临床常用剂量下藻酸双酯钠的这种抗粘附作用优于丹参。认为丹参、藻酸双酯钠的这种抗粘附作用可能是临床用以治疗脑血栓形成的一个重要机理。  相似文献   
74.
Besides clinical efficacy, the mechanisms of action of deep brain stimulation (DBS) are still debated. To shed light on this complex issue, we have taken the opportunity to record the response of globus pallidus internus (GPi) neurones to 100 Hz stimulations in a case of Lesch-Nyhan syndrome (LNS) where four pallidal electrodes were implanted. Three types of response were observed, 2/19 neurones were unaffected by DBS. About 7/19 neurones were inhibited during DBS stimulation and 10/19 neurones were excited during DBS stimulation. Both effects ceased when DBS was turned off. Inhibited neurones were situated lower that exited ones on the trajectory (1.25 and 4.65 mm above the center of GPi respectively). These observations suggest that locally DBS induces a reversible inhibition of neurone firing rate while at the same time distantly exciting the main afferents to and/or efferents from the GPi. Both actions would result in a strong GPi inhibition that does not preclude increased outflow from the GPi.  相似文献   
75.
Fibrinolytic therapy substantially reduces mortality from acute myocardial infarction. Patient selection is, however, important. The patient must present within 12 hours of the onset ofischaemic symptoms, have definite ECG changes of ST elevation or left bundle branch block and no contraindications. The major contraindications are those for risk of an intracerebral bleed, recent stroke, intracranial tumour or risk of a major systemic bleed. Age and hypertension are not contraindications but may modify the regimen used.
Heparin is required with recombinant tissue plasminogen activator but is optional with streptokinase.
The recent COBALT trial suggests that the accelerated weight related t-PA regimen given over 90 minutes is more satisfactory than double bolus t-PA. However, inpatients under 75 years of age, the two regimens were equivalent.
For patients suffering acute myocardial infarction, practitioners should now individualise choice of therapy, rather than give the same cocktail to all patients. The choice of regimen will depend on the cardiac risk, the stroke risk, the bleeding risk and the cost.  相似文献   
76.
目的:总结和简述烧伤湿性医疗技术在治疗深度烧伤的临床应用经验。方法:对我院近年来150例深度烧伤病人全程股规范应用湿性医疗技术治疗的创面,深度创面采用耕耘疗法。结果:150例病人创面全部愈合,创面愈合时间最短10天,最长56天。没有一例植皮,创面均达到生理性愈合,无畸形,无功能障碍。结论:湿性疗法对深度烧伤疗效显著,深度烧伤创面能实现生理性愈合,达到烧伤皮肤原位再生之目的。  相似文献   
77.
目的 :探讨耕耘疗法在中小面积深度烧伤创面治疗中的疗效。方法 :对小面积深Ⅱ度~浅Ⅲ度烧伤创面进行了耕耘疗法 ,然后外用MEBO。结果 :治愈 16 5例 ,深Ⅱ度创面多在 17± 2 0天内愈合。浅Ⅲ度创面也在 2 8± 3 0天内愈合。结论 :通过采用耕耘方法可改善深度创面的局部微循环 ,尽快清除坏死组织 ,促进创面液化 ,充分发挥MEBO药效 ,使创面愈合期明显缩短 ,减少了疤痕率  相似文献   
78.
目的分析脑静脉血栓(CVT)病人的死亡原因。方法回顾分析136例CVT病人中5例死亡病例的病因、临床表现、影像学资料、治疗经过及死亡原因。结果病死率为3.7%。2例在急性期死亡,3例在慢性期死亡。直接死亡因素均为脑疝;间接死亡因素为颅内多发性出血和多个部位的脑静脉血栓形成,死亡组(3.20±0.84)支静脉受累,存活组(2.09±1.00)支静脉受累(P=0.016)。而性别、年龄、确诊时间、癫疒间发作、病灶部位及治疗前颅内压等没有显著增加死亡的危险性。某些临床表现,如失语、运动障碍、精神症状及意识障碍与死亡有关,但其系多发性颅内出血及多个部位脑静脉血栓所致。结论CVT病人的直接死亡原因为脑疝,间接原因为多发性脑静脉血栓和颅内多发性出血。死亡不仅可以发生在急性期,也可以出现在慢性期。  相似文献   
79.
目的探讨立体定向核团毁损术及脑深部电刺激术治疗非痉挛型脑瘫的疗效。方法将16例非痉挛型脑瘫病人分成三组:A组为肌张力障碍型,11例;B组为肌张力障碍合并震颤型,3例;C组为共济失调合并震颤型,2例。采用通用DT评分量表(GPS)评估病肢功能。分别采用立体定向核团毁损术及脑深部电刺激术治疗。术后随访1年,评估症状改善情况。结果A组肌张力障碍改善率为0—58.3%,平均17.1%;B组肌张力障碍改善率6.7%~25.0%,震颤改善率66.7%~75.0%;C组共济失调无明显变化,震颤改善率12.5%~25.0%。结论立体定向手术是治疗肌张力障碍型及震颤型脑瘫的可选择手段。  相似文献   
80.
Deep inspiration preceding Valsalva maneuver and rapid expiration immediately following it (DIVE) enhance venous blood flow on color Doppler flow imaging (CDI). The effect of DIVE was assessed in 115 consecutive lower extremity examinations. Of these, 95 or 115 (83%) had negative CDI sonograms, and 20 of 115 (17%) had partially (six of 115) or completely (14 of 115) occluding deep vein thrombosis. DIVE enhanced venous blood flow in 68% of the negative cases, resulting in transient venous distention, and/or more complete color filling, and/or greater spectral flow velocities. The 14 cases with completely occluding thrombi showed no response to DIVE. Six cases with partially occluding thrombi showed moderate to mild response to DIVE, with improved color delineation of the residual patent lumen around the thrombus. The authors conclude that DIVE facilitates deep venous CDI, especially when compression cannot be used to augment venous flow.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号