全文获取类型
收费全文 | 263024篇 |
免费 | 24954篇 |
国内免费 | 20515篇 |
专业分类
耳鼻咽喉 | 2011篇 |
儿科学 | 2301篇 |
妇产科学 | 3005篇 |
基础医学 | 32571篇 |
口腔科学 | 4270篇 |
临床医学 | 37870篇 |
内科学 | 38490篇 |
皮肤病学 | 2393篇 |
神经病学 | 14865篇 |
特种医学 | 9536篇 |
外国民族医学 | 198篇 |
外科学 | 25092篇 |
综合类 | 44074篇 |
现状与发展 | 74篇 |
一般理论 | 27篇 |
预防医学 | 15866篇 |
眼科学 | 8175篇 |
药学 | 28196篇 |
303篇 | |
中国医学 | 15579篇 |
肿瘤学 | 23597篇 |
出版年
2024年 | 934篇 |
2023年 | 4363篇 |
2022年 | 11336篇 |
2021年 | 14028篇 |
2020年 | 10654篇 |
2019年 | 9240篇 |
2018年 | 9676篇 |
2017年 | 8519篇 |
2016年 | 8096篇 |
2015年 | 12186篇 |
2014年 | 14967篇 |
2013年 | 12528篇 |
2012年 | 18733篇 |
2011年 | 21533篇 |
2010年 | 13038篇 |
2009年 | 10064篇 |
2008年 | 13339篇 |
2007年 | 13366篇 |
2006年 | 13596篇 |
2005年 | 13855篇 |
2004年 | 8203篇 |
2003年 | 7609篇 |
2002年 | 6374篇 |
2001年 | 5699篇 |
2000年 | 6426篇 |
1999年 | 7183篇 |
1998年 | 4737篇 |
1997年 | 4754篇 |
1996年 | 3675篇 |
1995年 | 3511篇 |
1994年 | 2898篇 |
1993年 | 1963篇 |
1992年 | 2213篇 |
1991年 | 1842篇 |
1990年 | 1565篇 |
1989年 | 1334篇 |
1988年 | 1133篇 |
1987年 | 990篇 |
1986年 | 748篇 |
1985年 | 608篇 |
1984年 | 348篇 |
1983年 | 214篇 |
1982年 | 115篇 |
1981年 | 126篇 |
1980年 | 82篇 |
1979年 | 90篇 |
1965年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
后腹腔镜手术CO2气腹对脑氧供需平衡的影响 总被引:5,自引:2,他引:3
目的探讨后腹腔镜CO2气腹对脑氧供需平衡的影响. 方法选择后腹腔镜下肾及肾上腺肿瘤切除术20例,ASAⅠ~Ⅱ级,分别于气腹前,气腹后10、30、60 min和关气腹后30 min,抽取颈静脉球血和桡动脉血进行血气分析,比较不同时点动脉血PH(aPH )、颈静脉球PH(jvPH)、动脉血二氧化碳分压(PaCO2)、动脉血糖(aGS)、动脉血乳酸(aLac)、颈内静脉血氧分压(PjvO2)、颈内静脉血氧饱和度(SjvO2)、颅内动静脉氧含量差(AjvDO2)、颈内静脉血二氧化碳分压(PjvCO2)、血糖(jvGS)和乳酸(jvLac)的变化. 结果与气腹前比较,气腹后各时间点aPH、jvPH显著降低(P<0.05);PaCO2、PjvCO2气腹后各时间点与气腹前相比显著升高(P<0.05);AjvDO2气腹后各时点与气腹前相比显著下降(P<0.05);jvLac气腹后各时间点与气腹前相比有降低趋势,但无统计学差异(P>0.05);aGS、 jvGS气腹前后无显著变化(P>0.05). 结论后腹腔镜手术期间,脑血流量显著增加,未发现脑无氧代谢增加的证据. 相似文献
992.
Hongning Zhao Xiaoming Wang Junqiang Zhang Deben Yang Xiaoqiong Zhao Xin Liu Hui Huang Jianxiu Hu 《中国神经再生研究》2007,2(11):675-677
BACKGROUND: The examination of sympathetic skin response is an important index for assessing the autonomic nerve function, and patients with myasthenia gravis are always accompanied by dysautonomia. Therefore, it will be important to know whether sympathetic skin response can be used as the index for the clinical evaluation of myasthenia gravis.
OBJECTIVE: To investigate the diagnostic value of sympathetic skin response in the damage of autonomic nerve function of patients with myasthenia gravis.
DESIGN: A case-controlled comparative observation.
SETTING: Department of Neurology and Room of Nerve Electromyogram, the Affiliated Hospital of North Sichuan Medical College.
PARTICIPANTS: Thirty outpatients or inpatients with myasthenia gravis were selected from the Department of Neurology, the Affiliated Hospital of North Sichuan Medical College from May 2006 to May 2007, including 9 males and 21 females, aged 8–72 years with a mean age of (28±5) years old. They were all accorded with the diagnostic standards of myasthenia gravis, accompanied by different severity of autonomic nerve symptoms, including poor skin nutrition, sweating of hands and feet, pyknocardia, persistent hypotension, abdominal pain, constipation, etc. They all had not taken any drug affecting the autonomic nerve function before the examination. Informed consents were obtained from all the patients. Meanwhile, 30 healthy physical examinees were enrolled as the normal control group, including 10 males and 20 females, aged 10–75 years with a mean age of (31±5) years old. Approval was obtained from the hospital ethic committee.
METHODS: After admission, the patients were examined with sympathetic skin response using DANTEC keypoint 2.0 electromyography evoked potential apparatus (Danmark). The changes of the latency and wave amplitude of sympathetic skin response were observed. The subjects in the normal control group were examined with the same methods at physical examination. Abnormality was judged by the disappearance of wave form, latency longer than that in the normal control group by Mean±2.5SD, or wave amplitude lower than the average value in the normal control group by 50%.
MAIN OUTCOME MEASURES: The results of the latency and wave amplitude of sympathetic skin response were compared between the patients with myasthenia gravis and normal controls.
RESULTS: All the 30 patients with myasthenia gravis and 30 healthy physical examinees were involved in the final analysis of results. There were no significant differences between the left and right upper and lower limbs in both the myasthenia gravis group and normal control group (P > 0.05). In the myasthenia gravis group, the abnormal rate of sympathetic skin response was 37% (11/30), the latency was prolonged and the wave amplitude was decreased as compared with those in the normal control group, and there were significant differences (P < 0.01).
CONCLUSION: Sympathetic skin response can be used as an electrophysiological index for judging the damages of autonomic nerve function in patients with myasthenia gravis. 相似文献
993.
Attenuation correction in myocardial perfusion SPECT/CT: effects of misregistration and value of reregistration. 总被引:2,自引:0,他引:2
Sibyll Goetze Tracy L Brown William C Lavely Zhe Zhang Frank M Bengel 《Journal of nuclear medicine》2007,48(7):1090-1095
The accuracy of myocardial perfusion SPECT improves with attenuation correction. Algorithms for attenuation correction in hybrid SPECT/CT systems have the potential for misregistration of emission and transmission scans because CT and SPECT are obtained sequentially. Misregistration will influence regional tracer distribution and may reduce diagnostic accuracy. This study focused on the role of misregistration in cardiac SPECT/CT and the performance of a software-based approach for reregistration. METHODS: We included 105 consecutive patients who underwent clinical myocardial perfusion imaging on a SPECT/CT system. Images were quantitatively assessed for misregistration using fusion software. Results were recorded in millimeters in the x-, y-, and z-axes. Regional tracer uptake in 6 segments (anterior, septal, inferior, lateral, anteroapical, and inferoapical) for noncorrected and attenuation-corrected images before and after reregistration was obtained from polar maps. To determine the relative influence of misregistration, we correlated individual differences between noncorrected and attenuation-corrected images, as well as between attenuation-corrected images before and after reregistration, with the degree of misregistration in a multivariate analysis including additional clinical variables such as sex and body weight. RESULTS: The difference in regional radiotracer uptake was significant between noncorrected and attenuation-corrected images in all 6 segments and was most pronounced in the inferior wall. On multivariate analysis, misregistration contributed significantly to changes in radiotracer distribution in the anterior (P = 0.038), septal (P = 0.011), and inferior (P = 0.006) segments. The mean misregistration was 8.6 +/- 3.8 mm (1.25 +/- 0.55 pixel). Misregistration of one or more pixels was observed in 64% of studies. Reregistration of misalignment significantly affected regional radiotracer distribution in the segments shown to be influenced by misregistration. CONCLUSION: Misregistration occurs with SPECT/CT systems and influences regional tracer distribution on attenuation-corrected myocardial images. Reregistration of misaligned studies may be a useful tool for correction. The impact of this strategy on the diagnostic and prognostic accuracy of cardiac hybrid imaging needs to be determined. 相似文献
994.
目的探讨关节镜下松解术治疗冻结肩的疗效.方法2001年10月~2003年10月,我院对25例冻结肩在关节镜下行松解术.全麻下肩关节后路进镜,前路进射频电刀烧灼肱二头肌长头肌腱及肩袖间隙部位的滑膜充血炎症区,切割盂肱上韧带、盂肱中韧带、肩胛下肌肌腱关节囊内部分,手法松解剩余挛缩.25例术后3、6个月随访肩关节活动范围及美国肩肘协会评分(ASES).结果手术时间75~98 min,平均85 min.无术中并发症.25例除术后1周肩关节内旋与术前无明显改善外(x2=8.558,P=0.073),术后各个时期肩关节其它活动范围比术前均有明显改善(P<0.05).术后3个月和6个月比术后1周改善更明显(P<0.05).25例术后3个月和6个月ASES评分(87.4±4.6,88.1±6.0)均比术前(45.8±10.0)明显改善(q=28.738,29.221;P<0.05),但3个月与6个月评分相比较无显著性差异(q=0.484,P>0.05).结论肩关节镜下手术松解冻结肩可以明显缩短病程,取得稳定满意的效果. 相似文献
995.
大肠海绵状血管瘤的诊治(附8例报告) 总被引:2,自引:0,他引:2
目的 探讨大肠海绵状血管瘤的临床特点、诊治原则和疗效。方法回顾1997年至2004年收治的8例大肠海绵状血管瘤患者的临床资料。结果8例患者平均年龄18岁.其中直肠海绵状血管瘤4例.直肠和乙状结肠海绵状血管瘤3例.金大肠海绵状血管瘤1例。临床表现为反复发作的无痛性便血和贫血。术前行电子结肠镜、腹部X线平片、气钡双重对比造影、CT和MRI等检查明确诊断。昕有患者均行于术治疗.平均随访36月(10~96月).全部治愈。结论增强对本病的认识.重视电亍二结肠镜仵大肠海绵状血管瘤的首诊作用.影像学检杏进一步确定病变部位和血管瘤的范围,手术治疗是有效的治疗手段。 相似文献
996.
目的:探讨分叉带锁髓内钉治疗肱骨干骨折临床经验。方法:采用顺行和逆行分叉肱骨带锁髓内钉治疗肱骨干骨折25例。结果:随访平均26个月,优16例,良7例,可2例,优良率92%。除肩关节活动受限2例外,其余均完全恢复肩关节和肘关节功能。结论:分叉带锁髓内钉适应于肱骨骨折,其坚强-动态固定的有机结合有利于骨折的愈合。方法简单,固定可靠,创伤小,是一种较好的手术方法。 相似文献
997.
Chen Xinshan Zhang Yigu Rao Guangxun Huang Guangzhao 《Frontiers of Medicine in China》2007,1(3):338-342
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a kind of primary myocardial disease characterized by the regional
or global replacement of right ventricular myocardium by fatty and fibrolipomatous tissues. The ARVC, usually presenting with
different clinical manifestations and pathological changes, were mainly seen in young men and is one of the main causes of
sudden death in the young. Here two autopsied cases of Chinese men aged 30 and 23 years old who appeared healthy but died
suddenly while at work are reported respectively. One of the victims had extensive and severe pathological changes in his
heart involving the left ventricular wall as well as the ventricular septum and the right atrium. Not only was there a global
fatty and fibrolipomatous tissue replacement of the right ventricular myocardia, but also mild sarcoplasmic coagulation in
the myocardium and focal lymphocytic infiltration in the myocardial interstitium of the right ventricular wall. In addition,
slight atherosclerosis of the coronary artery and intimal thickening of the sino-atrial node were observed. It is believed
that there are no marked differences in the pathological changes of ARVC between Chinese patients and patients from western
countries. The etiology and pathogenesis of ARVC could not be explained by a single cause or factor and they are probably
related to various congenital and acquired causes or factors. 相似文献
998.
新基因Tctex5在雄鼠生殖细胞中的表达 总被引:1,自引:0,他引:1
目的探讨雄鼠生殖细胞中是否有Tctex5基因的表达。方法从三株体外培养的雄鼠生殖细胞CRL-1715、CRL-2053和CRL-2196细胞株中提取总RNA和蛋白,采用RT-PCR和Western blot分别从mRNA和蛋白质水平分析基因产物的表达。结果Tctex5基因在CRL-1715、CRL-2053、CRL-2196三株细胞中都有高表达。结论Tctex5基因作为一个未知功能的基因,在雄鼠生殖细胞中有丰富的表达,可能参与了精子发生的功能调节,作为男性正常生育的。个新的标志物,它可能在精子发生中扮演了一个重要的角色,该基因在雄性生殖细胞中的发现可能会对男性不育的诊断与治疗提供新的途径。 相似文献
999.
1000.
Yue Huan-xun Zhang Xun Jiang Min Li Fu-ping Ning Gang Tian Yu Lin Li Zhang Si-xiao 《生殖医学杂志》2008,17(Z1)
0This article describes 2 infertile brothers of asoospermia equally associated with co-existing sinusitis,bronchiectasis,and situs inversus and their family history.These two cases were diagnosed as Kartagener syndrome(KS).The patients were not offspring of kin marriages but their family members with scattered bronchi-pulmouary infections were discovered.No one manifests azoospermia,dextrocardia or situs inversus in the paternal family ex-cept two cases reported.No abnormalities were found in their mother-side family.KS should be differentiated from Young's syndrome,cystic fibrosis(CF),and other diseases such as Kallmann's syndrome in male infertility clinic. 相似文献