全文获取类型
收费全文 | 46465篇 |
免费 | 4203篇 |
国内免费 | 1643篇 |
专业分类
耳鼻咽喉 | 399篇 |
儿科学 | 796篇 |
妇产科学 | 459篇 |
基础医学 | 4019篇 |
口腔科学 | 896篇 |
临床医学 | 5214篇 |
内科学 | 6388篇 |
皮肤病学 | 539篇 |
神经病学 | 2652篇 |
特种医学 | 1679篇 |
外科学 | 4820篇 |
综合类 | 8321篇 |
现状与发展 | 4篇 |
一般理论 | 20篇 |
预防医学 | 5245篇 |
眼科学 | 650篇 |
药学 | 4585篇 |
33篇 | |
中国医学 | 2937篇 |
肿瘤学 | 2655篇 |
出版年
2024年 | 141篇 |
2023年 | 399篇 |
2022年 | 1052篇 |
2021年 | 1380篇 |
2020年 | 1090篇 |
2019年 | 827篇 |
2018年 | 843篇 |
2017年 | 1044篇 |
2016年 | 884篇 |
2015年 | 1501篇 |
2014年 | 1914篇 |
2013年 | 2599篇 |
2012年 | 3737篇 |
2011年 | 3989篇 |
2010年 | 3169篇 |
2009年 | 2796篇 |
2008年 | 3241篇 |
2007年 | 3376篇 |
2006年 | 3163篇 |
2005年 | 2798篇 |
2004年 | 2236篇 |
2003年 | 1945篇 |
2002年 | 1793篇 |
2001年 | 824篇 |
2000年 | 662篇 |
1999年 | 427篇 |
1998年 | 272篇 |
1997年 | 276篇 |
1996年 | 197篇 |
1995年 | 196篇 |
1994年 | 196篇 |
1993年 | 201篇 |
1992年 | 170篇 |
1991年 | 135篇 |
1990年 | 143篇 |
1989年 | 141篇 |
1988年 | 171篇 |
1987年 | 126篇 |
1986年 | 147篇 |
1985年 | 130篇 |
1984年 | 150篇 |
1983年 | 167篇 |
1982年 | 151篇 |
1981年 | 148篇 |
1980年 | 146篇 |
1979年 | 82篇 |
1978年 | 83篇 |
1977年 | 88篇 |
1976年 | 65篇 |
1974年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Xiaoguang Zhu Raymond Q Migrino Robert S Hellman Tejas Brahmbhatt Ming Zhao 《Nuclear medicine communications》2008,29(9):764-769
OBJECTIVE: The C2A domain of Synaptotagmin I is a molecular probe for the specific imaging of cell death. Here we test the hypothesis that the uptake of 99mTc-C2A in the acute phase of an infarction is associated with cardiac dysfunction in follow-ups. METHODS: The left coronary artery was occluded in Sprague-Dawley rats for 0, 10, 20, and 30 min. 99mTc-C2A was injected intravenously at 2 h of reperfusion. Anterior planar images were acquired with one million counts on a gamma camera 3 h after injection. 99mTc-C2A uptake was calculated as the total counts in the left ventricle region minus blood pool signal. The in-vivo signal detected was correlated with wall motion score index at 1 and 3 weeks follow-ups measured by echocardiography. RESULTS: 99mTc-C2A uptake was higher with increased ischemic time (2244+/-852, 4054+/-1223, and 6178+/-1451 for 10, 20, and 30 min ischemia, analysis of variance P<0.001). A significant correlation was found between 99mTc-C2A uptake and wall motion score index at 1 week (R=0.800, P=0.0006) and 3 weeks (R=0.810, P=0.0008). CONCLUSION: In this ischemia/reperfusion model, 99mTc-C2A uptake in the acute phase was associated with functional abnormality at 1 and 3 weeks. This demonstrates the potential diagnostic and prognostic value of 99mTc-C2A as a novel imaging agent. 相似文献
53.
Hung-Fat Tse Sukumaran Thambar Yok-Lam Kwong Philip Rowlings Greg Bellamy Jane McCrohon Paul Thomas Bruce Bastian John K F Chan Gladys Lo Chi-Lai Ho Wing-Sze Chan Raymond Y Kwong Anthony Parker Thomas H Hauser Jenny Chan Daniel Y T Fong Chu-Pak Lau 《European heart journal》2007,28(24):2998-3005
AIMS: Experimental studies have demonstrated that bone marrow (BM) cells can induce angiogenesis in ischaemic myocardium. Recently, several non-randomized pilot studies have also suggested that direct BM cells implantation appears to be feasible and safe in patients with severe coronary artery diseases (CAD). METHODS AND RESULTS: We performed a randomized, blinded, and placebo-controlled trial in 28 CAD patients. After BM harvesting, we assigned patients to receive low dose (1 x 10(6) cells/0.1 mL, n = 9), high dose (2 x 10(6) cells/0.1 mL, n = 10) autologous BM cells or control (0.1 mL autologous plasma/injection, n = 9) catheter-based direct endomyocardial injection as guided by electromechanical mapping. Our primary endpoint was the increase in exercise treadmill time and our secondary endpoints were changes in Canadian Cardiovascular Society (CCS) and New York Heart Association (NYHA) class, and myocardial perfusion and left ventricular ejection fraction (LVEF) assessed by single-photon emission computed tomography and magnetic resonance imaging, respectively. A total 422 injections (mean 14.6 +/- 0.7 per patient) were successfully performed at 41 targeted ischaemic regions without any acute complication. Baseline exercise treadmill time was 439 +/- 182 s in controls and 393 +/- 136 s in BM-treated patients, and changed after 6 months to 383 +/- 223s and 464 +/- 196 s [BM treatment effect +0.43 log seconds (+53%), 95% CI 0.11-0.74, P = 0.014]. Compared with placebo injection, BM implantation was associated with a significant increase in LVEF (BM treatment effect +5.4%, 95% CI 0.4-10.3, P = 0.044) and a lower NYHA class (odds ratio for treatment effect 0.12, 95% CI 0.02-0.73, P = 0.021) after 6 months, but CCS reduced similarly in both groups. We observed no acute or long-term complications, including ventricular arrhythmia, myocardial damage, or development of intramyocardial tumour or calcification associated with BM implantation. CONCLUSION: Direct endomyocardial implantation of autologous BM cells significantly improved exercise time, LVEF, and NYHA functional class in patients with severe CAD who failed conventional therapy. 相似文献
54.
目的 揭示大脑中动脉闭塞(MCAO)后丘脑钙调磷酸酶(CaN)的时空变化规律,探讨CaN的作用机制。方法 制备大鼠大脑中动脉永久性闭塞模型,分别测定缺血后不同时间点病灶侧丘脑CaN的活性和含量。结果 缺血后24h始丘脑CaN的含量下降且不恢复;CaN的活性在缺血后2h和4h减弱,6h始恢复至正常水平。可见,CaN的活性与含量分离。结论 大脑中动脉闭塞后丘脑CaN活性独特的时间变化规律显示其参与介导继发性丘脑损伤,可能具有毒性作用。 相似文献
55.
Sobel Somani Leslie D Mackeen Yair Morad J Raymond Buncic Derek C Armstrong John H Phillips Alex V Levin 《Journal of AAPOS》2003,7(1):54-59
PURPOSE: To determine whether 3-dimensional ultrasonography (3D US) provides information about anatomy and position of extraocular muscles to better guide surgeons approaching strabismus in patients with craniosynostosis who often have anomalous or absent eye muscles. METHODS: The 4 rectus eye muscles were imaged using 3D US for 7 children with craniosynostosis before or after strabismus surgery. Reconstructed 3D images were interpreted as having normal or abnormal anatomy and position, based on comparison with images acquired from 6 normal eyes. Interpretation was validated against the intraoperative findings from strabismus surgery. RESULTS: A total of 34 scans from the study group were used for comparison and validation purposes. Accuracy of anatomical assessments was 85% +/- 12% (percentage +/- confidence interval) and of positional assessments was 62% +/- 16%. Sensitivity and specificity of anatomical assessments was 80% +/- 14% and 88% +/- 10%, respectively. Anatomic anomalies detected by 3D US included excessively thick, thin, scarred and fibrotic, and absent muscles. Sensitivity and specificity of positional assessments was 48% +/- 17% and 85% +/- 12%, respectively. Positional anomalies such as muscle displacement off the normal clock hour axis or posteriorly displaced insertion were also detected. CONCLUSIONS: The 3D US may have an adjunctive role in determining anatomy and position of rectus muscles in patients with craniosynostosis, although it was more accurate in assessing anatomic features rather than positional features of rectus muscles. 相似文献
56.
57.
目的 探究注意缺陷多动障碍儿童初始沙盘游戏特征.方法 对29名注意缺陷多动障碍儿童和29名正常儿童进行沙盘游戏干预,对照分析两组儿童初始沙盘游戏主题及沙具使用情况.结果 注意缺陷多动障碍儿童沙盘游戏主题较正常儿童混乱无序,两组比较差异有统计学意义(χ2=22.58,P<0.00);两组儿童在沙具使用方面比较差异无统计学意义(均P>0.05).结论 注意缺陷多动障碍儿童沙盘游戏具有独特特征以及一定的临床诊断筛查价值. 相似文献
58.
Marcus P Kennedy Raymond D Coakley Scott H Donaldson Robert M Aris Kathy Hohneker Joel P Wedd Michael R Knowles Peter H Gilligan James R Yankaskas 《Journal of cystic fibrosis》2007,6(4):267-273
BACKGROUND: The impact of infection with Burkholderia gladioli in cystic fibrosis, other chronic airway diseases and immunosuppressed patients is unknown. METHODS: A six-year retrospective review of all patients with B. gladioli infection was performed in a tertiary referral center with cystic fibrosis and lung transplantation programs. In addition, a targeted survey of all 251 lung transplant recipients was performed. Available B. gladioli isolates were analyzed via pulsed field gel electrophoresis. RESULTS: Thirty-five patients were culture positive for B. gladioli, including 33 CF patients. No bacteremia was identified. Isolates were available in 18 patients and all were genetically distinct. Two-thirds of these isolates were susceptible to usual anti-pseudomonal antibiotics. After acquisition, only 40% of CF patients were chronically infected (> or =2 positive cultures separated by at least 6 months). Chronic infection was associated with resistance to > or =2 antibiotic groups on initial culture and failure of eradication after antibiotic therapy. The impact of acquisition of B. gladioli infection in chronic infection was variable. Three CF patients with chronic infection underwent lung transplantation. One post-transplant patient developed a B. gladioli mediastinal abscess, which was treated successfully. CONCLUSIONS: The majority of patients' culture positive for B. gladioli at our center have CF. B. gladioli infection is often transient and is compatible with satisfactory post-lung transplantation outcomes. 相似文献
59.
目的 探讨通过门静脉系统局部应用白细胞介素 12 (IL 12 )对于肝转移肿瘤的治疗作用。方法 通过门静脉注射 2× 10 5个MCA 2 0 5肿瘤细胞建立小鼠肝转移肿瘤模型 ,同时脾脏被移植到皮下 ,作为反复多次向门静脉系统注射的途径。第 3~ 7天 ,0 1μgIL 12通过腹腔或脾脏注射 ,同时对照组中通过脾脏注射等体积的平衡盐水。第 2 1天检查肝转移肿瘤的情况。结果 在肝转移模型中 ,IL 12腹腔注射组和IL 12脾脏注射组的肝脏重量 (1 33± 0 0 8)g和 (1 2 9± 0 0 7)g明显小于对照组 (1 92± 0 17)g ,P <0 0 5 ,IL 12腹腔注射组和IL 12脾脏注射组的肝脏转移结节数目 (1 5 3± 0 5 8,0 6 0± 0 89)明显少于对照组 (18 2 5± 5 71,P <0 0 5 )。在IL 12脾脏注射组中 (n =6 ) ,3只小鼠的肝脏肿瘤完全消失。结论 通过门静脉系统局部应用IL 12是治疗肝转移肿瘤的有效方法。 相似文献
60.