全文获取类型
收费全文 | 47295篇 |
免费 | 3069篇 |
国内免费 | 371篇 |
专业分类
耳鼻咽喉 | 716篇 |
儿科学 | 685篇 |
妇产科学 | 616篇 |
基础医学 | 7238篇 |
口腔科学 | 1010篇 |
临床医学 | 4253篇 |
内科学 | 9568篇 |
皮肤病学 | 1518篇 |
神经病学 | 3699篇 |
特种医学 | 2709篇 |
外国民族医学 | 1篇 |
外科学 | 6807篇 |
综合类 | 333篇 |
一般理论 | 21篇 |
预防医学 | 2589篇 |
眼科学 | 875篇 |
药学 | 4119篇 |
中国医学 | 455篇 |
肿瘤学 | 3523篇 |
出版年
2024年 | 45篇 |
2023年 | 423篇 |
2022年 | 1138篇 |
2021年 | 2025篇 |
2020年 | 949篇 |
2019年 | 1388篇 |
2018年 | 1672篇 |
2017年 | 1242篇 |
2016年 | 1627篇 |
2015年 | 2069篇 |
2014年 | 2566篇 |
2013年 | 2889篇 |
2012年 | 4395篇 |
2011年 | 4322篇 |
2010年 | 2396篇 |
2009年 | 2064篇 |
2008年 | 3012篇 |
2007年 | 2741篇 |
2006年 | 2398篇 |
2005年 | 2175篇 |
2004年 | 1739篇 |
2003年 | 1513篇 |
2002年 | 1251篇 |
2001年 | 831篇 |
2000年 | 756篇 |
1999年 | 552篇 |
1998年 | 249篇 |
1997年 | 164篇 |
1996年 | 145篇 |
1995年 | 98篇 |
1994年 | 108篇 |
1993年 | 99篇 |
1992年 | 161篇 |
1991年 | 173篇 |
1990年 | 188篇 |
1989年 | 154篇 |
1988年 | 135篇 |
1987年 | 128篇 |
1986年 | 110篇 |
1985年 | 87篇 |
1984年 | 56篇 |
1983年 | 46篇 |
1982年 | 45篇 |
1981年 | 55篇 |
1980年 | 29篇 |
1979年 | 46篇 |
1978年 | 40篇 |
1977年 | 28篇 |
1975年 | 24篇 |
1970年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Clinical usefulness of intraductal ultrasonography for the management of acute biliary pancreatitis 下载免费PDF全文
23.
Fluid is usually restricted during thoracic surgery, and vasoactive agents are often administered to maintain blood pressure. One-lung ventilation (OLV) decreases arterial oxygenation; thus oxygen delivery to the brain can be decreased. In this study, we compared phenylephrine and dopamine with respect to maintaining cerebral oxygenation during OLV in major thoracic surgery.Sixty-three patients undergoing lobectomies were randomly assigned to the dopamine (D) or phenylephrine (P) group. The patients’ mean arterial pressure was maintained within 20% of baseline by a continuous infusion of dopamine or phenylephrine. Maintenance fluid was kept at 5 mL/kg/h. The depth of anesthesia was maintained with desflurane 1MAC and remifentanil infusion under bispectral index guidance. Regional cerebral oxygen saturation (rScO2) and hemodynamic variables were recorded using near-infrared spectroscopy and esophageal cardiac Doppler.The rScO2 was higher in the D group than the P group during OLV (OLV 60 min: 71 ± 6% vs 63 ± 12%; P = 0.03). The number of patients whose rScO2 dropped more than 20% from baseline was 0 and 6 in the D and P groups, respectively (P = 0.02). The D group showed higher cardiac output, but lower mean arterial pressure than the P group (4.7 ± 1.0 vs 3.9 ± 1.2 L/min; 76.7 ± 8.1 vs 84.5 ± 7.5 mm Hg; P = 0.02, P = 0.02). Among the variables, age, hemoglobin concentration, and cardiac output were associated with rScO2 by correlation analysis.Dopamine was superior to phenylephrine in maintaining cerebral oxygenation during OLV in thoracic surgery. 相似文献
24.
25.
目的 本研究使用激光扫描检眼镜(SLO)评价双侧中央暗点患者使用棱镜后的眼球运动反应.方法 本预试验共招募6例有双侧中央暗点的年龄相关性黄斑变性(AMD)患者以及6例正常视力的志愿者.首先用Nidek MP-1微视野仪确认患者的中央暗点和优选视网膜注视点(PRL),然后用Rodenstock SLO,在将视标投射在优选视网膜注视点时拍下实时视网膜像,接着在受检者眼前加入6~8 PD的棱镜,要求受检者保持注视视标,这时通过视网膜标记来测量视网膜像的移位量,以及随后发生的优选视网膜注视点的再次注视.过程中平均移位量和再次注视时间通过图像软件(ImageJ software)来计算.结果 实验组再次注视时的移位量在3个像素点或11.66个弧分之内(x轴:2.90±3.92,y轴:2.53±4.18).对照组再次注视时的移位会准确些(x轴:0.33±1.15,y轴:0.89±2.50),但与实验组差异无统计学意义(tx=1.32,Px>0.05;ty=0.80,Py>0.05).对照组再次注视时间(0.98±0.19)s较实验组(2.83±1.63)s要短,差距有统计学意义(t=5.03,P<0.01).其中有1例实验组受检者没有发生再次注视,其结果被排除并单独分析.结论 研究发现,双眼中央暗点患者对棱镜物像转移后的再注视反应与正常人接近,但实验组再注视明显较对照组慢,并有1例受检者没有发生再注视.该数据说明双侧中央暗点患者无论眼前有没有棱镜,都会利用相同的视网膜位置视物,因此,通过棱镜物像再定位的意义不大. 相似文献
26.
Joshua Manghelli Lisa Brown Hany B. Tadros Nabil A. Munfakh 《Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital》2015,42(5):491-494
The inflammatory response induced by cardiopulmonary bypass decreases vascular tone, which in turn can lead to vasoplegic syndrome. Indeed the hypotension consequent to on-pump cardiac surgery often necessitates vasopressor and intravenous fluid support. Methylene blue counteracts vasoplegic syndrome by inhibiting the formation of nitric oxide.We report the use of methylene blue in a 75-year-old man who developed vasoplegic syndrome after cardiac surgery. After the administration of methylene blue, his hypotension improved to the extent that he could be weaned from vasopressors. The use of methylene blue should be considered in patients who develop hypotension refractory to standard treatment after cardiac surgery. 相似文献
27.
Andriy
Derkach Steven C. Moore Simina M. Boca Joshua N. Sampson 《Statistics in medicine》2020,39(18):2423-2436
We consider the scenario where there is an exposure, multiple biologically defined sets of biomarkers, and an outcome. We propose a new two-step procedure that tests if any of the sets of biomarkers mediate the exposure/outcome relationship, while maintaining a prespecified familywise error rate. The first step of the proposed procedure is a screening step that removes all groups that are unlikely to be strongly associated with both the exposure and the outcome. The second step adapts recent advances in postselection inference to test if there are true mediators in each of the remaining candidate sets. We use simulation to show that this simple two-step procedure has higher statistical power to detect true mediating sets when compared with existing procedures. We then use our two-step procedure to identify a set of Lysine-related metabolites that potentially mediate the known relationship between increased body mass index and the increased risk of estrogen-receptor positive breast cancer in postmenopausal women. 相似文献
28.
Darren R. Feldman MD Yasser Ged MBBS Chung-Han Lee PhD Andrea Knezevic MS Ana M. Molina MD Ying-Bei Chen PhD Joshua Chaim DO Devyn T. Coskey MS Samuel Murray MS Satish K. Tickoo MD Victor E. Reuter MD Sujata Patil PhD Han Xiao MD Jahan Aghalar MD Arlyn J. Apollo MD Maria I. Carlo MD Robert J. Motzer MD Martin H. Voss MD 《Cancer》2020,126(24):5247-5255
29.
Three‐Dimensional Echocardiographic Evaluation of Mitral Apparatus during Preload Manipulation in Patients with Hypertrophic Cardiomyopathy 下载免费PDF全文
Hyemoon Chung M.D. Ji Hyun Yoon M.D. Young Won Yoon M.D. Ph.D. Ji Young Chung B.N. Jung‐Joon Cha M.D. Jong‐Youn Kim M.D. Ph.D. Pil‐Ki Min M.D. Ph.D. Byoung‐Kwon Lee M.D. Ph.D. Bum‐Kee Hong M.D. Ph.D. Se‐Joong Rim M.D. Ph.D. Hyuck Moon Kwon M.D. Eui‐Young Choi M.D. Ph.D. 《Echocardiography (Mount Kisco, N.Y.)》2015,32(8):1261-1269
30.