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   1371191篇
  免费   104740篇
  国内免费   5135篇
耳鼻咽喉   17235篇
儿科学   44493篇
妇产科学   37327篇
基础医学   202017篇
口腔科学   36581篇
临床医学   133000篇
内科学   266824篇
皮肤病学   27014篇
神经病学   115272篇
特种医学   49498篇
外国民族医学   368篇
外科学   189120篇
综合类   30826篇
现状与发展   2篇
一般理论   462篇
预防医学   116242篇
眼科学   29501篇
药学   102064篇
  14篇
中国医学   4101篇
肿瘤学   79105篇
  2021年   12435篇
  2019年   12658篇
  2018年   17428篇
  2017年   13216篇
  2016年   14216篇
  2015年   16463篇
  2014年   22447篇
  2013年   34006篇
  2012年   46788篇
  2011年   49465篇
  2010年   28642篇
  2009年   26365篇
  2008年   44861篇
  2007年   47184篇
  2006年   47143篇
  2005年   45485篇
  2004年   43314篇
  2003年   40949篇
  2002年   39611篇
  2001年   61771篇
  2000年   63430篇
  1999年   53118篇
  1998年   14942篇
  1997年   13533篇
  1996年   13395篇
  1995年   12667篇
  1994年   11824篇
  1993年   11087篇
  1992年   42035篇
  1991年   41146篇
  1990年   39826篇
  1989年   37716篇
  1988年   34910篇
  1987年   33990篇
  1986年   32441篇
  1985年   30872篇
  1984年   23230篇
  1983年   19740篇
  1982年   11845篇
  1979年   20959篇
  1978年   14907篇
  1977年   12142篇
  1976年   11939篇
  1975年   12173篇
  1974年   14890篇
  1973年   14563篇
  1972年   13444篇
  1971年   12503篇
  1970年   11558篇
  1969年   10489篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
Nevo  N.  Goldstein  A. L.  Staierman  M.  Eran  N.  Carmeli  I.  Rayman  S.  mnouskin  Y. 《Hernia》2022,26(6):1491-1499
Hernia - The minimally invasive surgical repair of combined inguinal and ventral hernias often requires shifting from one approach or plane to another. The traditional enhanced-view totally...  相似文献   
74.
75.
76.
Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
77.
78.
Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices.With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored.With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres.Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected.Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5.MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink.  相似文献   
79.
80.
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