全文获取类型
收费全文 | 84808篇 |
免费 | 7548篇 |
国内免费 | 228篇 |
专业分类
耳鼻咽喉 | 807篇 |
儿科学 | 2174篇 |
妇产科学 | 2016篇 |
基础医学 | 11947篇 |
口腔科学 | 1702篇 |
临床医学 | 9366篇 |
内科学 | 15972篇 |
皮肤病学 | 1128篇 |
神经病学 | 8502篇 |
特种医学 | 3030篇 |
外国民族医学 | 57篇 |
外科学 | 12347篇 |
综合类 | 1446篇 |
现状与发展 | 1篇 |
一般理论 | 78篇 |
预防医学 | 8368篇 |
眼科学 | 2119篇 |
药学 | 6052篇 |
中国医学 | 138篇 |
肿瘤学 | 5334篇 |
出版年
2022年 | 660篇 |
2021年 | 1520篇 |
2020年 | 942篇 |
2019年 | 1429篇 |
2018年 | 1707篇 |
2017年 | 1258篇 |
2016年 | 1316篇 |
2015年 | 1491篇 |
2014年 | 2268篇 |
2013年 | 3205篇 |
2012年 | 4783篇 |
2011年 | 4938篇 |
2010年 | 2857篇 |
2009年 | 2542篇 |
2008年 | 4591篇 |
2007年 | 4765篇 |
2006年 | 4623篇 |
2005年 | 4495篇 |
2004年 | 4408篇 |
2003年 | 4048篇 |
2002年 | 3828篇 |
2001年 | 1845篇 |
2000年 | 1935篇 |
1999年 | 1744篇 |
1998年 | 1017篇 |
1997年 | 894篇 |
1996年 | 844篇 |
1995年 | 781篇 |
1994年 | 729篇 |
1993年 | 652篇 |
1992年 | 1295篇 |
1991年 | 1297篇 |
1990年 | 1175篇 |
1989年 | 1147篇 |
1988年 | 1163篇 |
1987年 | 1024篇 |
1986年 | 1000篇 |
1985年 | 979篇 |
1984年 | 845篇 |
1983年 | 736篇 |
1982年 | 574篇 |
1981年 | 530篇 |
1980年 | 490篇 |
1979年 | 746篇 |
1978年 | 628篇 |
1977年 | 553篇 |
1976年 | 500篇 |
1975年 | 471篇 |
1974年 | 512篇 |
1973年 | 494篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
PT Foley A Ganeshan S Anthony R Uberoi 《Journal of Medical Imaging and Radiation Oncology》2010,54(1):9-16
This is a retrospective review of the results at our institution of using multi-detector CT angiography (CTA) to localise lower gastrointestinal (GI) bleeding. We hypothesised that in our patient population: (i) CTA was unlikely to demonstrate bleeding in patients who were haemodynamically stable; (ii) in haemodynamically unstable patients in whom CTA was undertaken, the results could be used to select patients who would benefit from catheter angiography; and (iii) in haemodynamically unstable patients in whom CTA was undertaken, a subgroup of patients could be identified who would benefit from primary surgical treatment, avoiding invasive angiography completely. A retrospective review was conducted of the clinical records of all patients undergoing CTA for lower GI haemorrhage at our institution between 1 January 2005 and 30 June 2007. Out of the 20 patients examined, 10 had positive CTAs demonstrating the bleeding site. Nine were haemodynamically unstable at the time of the study. Four patients with positive CT angiograms were able to be treated directly with surgery and avoided invasive angiography. Ten patients had negative CTAs. Four of these were haemodynamically unstable, six haemodynamically stable. Only one required intervention to secure haemostasis, the rest stopped spontaneously. No haemodynamically stable patient who had a negative CTA required intervention. CTA is a useful non-invasive technique for localising the site of lower GI bleeding. In our patient population, in the absence of haemodynamic instability, the diagnostic yield of CTA was low and bleeding was likely to stop spontaneously. In haemodynamically unstable patients, a positive CTA allowed patients to be triaged to surgery or angiography, whereas there was a strong association between a negative CTA and spontaneous cessation of bleeding. 相似文献
82.
Anthony M Dart Jan Erik Otterstad Bridget-Anne Kirwan John D Parker Sophie de Brouwer Philip A Poole-Wilson Jacobus Lubsen 《European journal of echocardiography》2007,8(4):275-283
AIMS: To evaluate the relationship between echocardiographic cardiac function and outcome in patients with stable symptomatic angina. METHODS: Baseline echo left ventricular ejection fraction and volume data measured in a central laboratory was available for 7016 patients (92% of the total) participating in the ACTION trial (A Coronary disease Trial Investigating Outcome with Nifedipine GITS). Ejection fraction was also measured by investigators. Evaluation of the different echocardiographic variables was based on adjusted hazard ratios comparing the unfavourable limit of the 90% range of the variable concerned to the favourable limit. RESULTS: The centrally measured ejection fraction was the most powerful predictor of all-cause death (adjusted hazard ratio=2.5), myocardial infarction, any stroke or transient ischaemic attack and overt heart failure (adjusted hazard ratio=4.5). The addition of either end systolic volume or end diastolic volume to ejection fraction did not materially affect the power of prediction. Compared to the central ejection fraction measurement, the investigator-measured ejection fraction was a less powerful predictor for all outcomes considered. CONCLUSION: Routine echocardiography carefully analysed by standardised methods provides useful prognostic information in patients with stable angina, including for total mortality. 相似文献
83.
84.
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
85.
Varatharaj Mounasamy Christopher Dawson Quanjun Cui William M. Mihalko Khaled J. Saleh Thomas Brown 《European journal of orthopaedic surgery & traumatology : orthopedie traumatologie》2007,17(3):313-315
Direct vascular injury after primary total knee arthroplasty is rare. This case report illustrates a 65-year-old female who was diagnosed with a pseudoaneurysm of the popliteal artery when she was investigated for increased leg swelling and pain 1 week after total knee arthroplasty. She had a percutaneous endovascular repair with a stent after thrombectomy. 相似文献
86.
Neuro-muscular transmission in the extrinsic muscles of the eye 总被引:5,自引:0,他引:5
87.
88.
Immunization with amyloid-β (Aβ) peptide reduces amyloid load in animal studies and in humans; however clinical trials resulted in the development of a pro-inflammatory cellular response to Aβ. Apoptosis has been employed to stimulate humoral and Th2-biased cellular immune responses. Thus, we sought to investigate whether immunization using a DNA vaccine encoding Aβ in conjunction with an attenuated caspase generates therapeutically effective antibodies. Plasmids encoding Aβ and an attenuated caspase were less effective in reducing amyloid pathology than those encoding Aβ alone. Moreover, use of Aβ with an Arctic mutation (E22G) as an immunogen was less effective than wild-type Aβ in terms of improvements in pathology. Low levels of IgG and IgM were generated in response to immunization with a plasmid encoding wild-type Aβ. These antibodies decreased plaque load by as much as 36 ± 8% and insoluble Aβ42 levels by 56 ± 3%. Clearance of Aβ was most effective when antibodies were directed against N-terminal epitopes of Aβ. Moreover, immunization reduced CAA by as much as 69 ± 12% in TgCRND8 mice. Finally, high-molecular-weight oligomers and Aβ trimers were significantly reduced with immunization. Thus, immunization with a plasmid encoding Aβ alone drives an attenuated immune response that is sufficient to clear amyloid pathology in a mouse model of Alzheimer's disease. 相似文献
89.
90.