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   2394631篇
  免费   186275篇
  国内免费   9784篇
耳鼻咽喉   30668篇
儿科学   78224篇
妇产科学   65470篇
基础医学   339586篇
口腔科学   65948篇
临床医学   225538篇
内科学   474539篇
皮肤病学   52834篇
神经病学   198631篇
特种医学   92345篇
外国民族医学   622篇
外科学   352592篇
综合类   55371篇
现状与发展   3篇
一般理论   849篇
预防医学   200766篇
眼科学   51880篇
药学   172240篇
  11篇
中国医学   4914篇
肿瘤学   127659篇
  2018年   26456篇
  2017年   20399篇
  2016年   23291篇
  2015年   26359篇
  2014年   36600篇
  2013年   56032篇
  2012年   72272篇
  2011年   77329篇
  2010年   46585篇
  2009年   44313篇
  2008年   71300篇
  2007年   75631篇
  2006年   76891篇
  2005年   74324篇
  2004年   70862篇
  2003年   68203篇
  2002年   65393篇
  2001年   109646篇
  2000年   112726篇
  1999年   94615篇
  1998年   28215篇
  1997年   25371篇
  1996年   25964篇
  1995年   25560篇
  1994年   23938篇
  1993年   22432篇
  1992年   77391篇
  1991年   75549篇
  1990年   72923篇
  1989年   69279篇
  1988年   64388篇
  1987年   63127篇
  1986年   59957篇
  1985年   57636篇
  1984年   43917篇
  1983年   37042篇
  1982年   22926篇
  1981年   20476篇
  1980年   19168篇
  1979年   39725篇
  1978年   28781篇
  1977年   23910篇
  1976年   22744篇
  1975年   23480篇
  1974年   28129篇
  1973年   27189篇
  1972年   25128篇
  1971年   23288篇
  1970年   21404篇
  1969年   19812篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
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   
73.
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