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   1713742篇
  免费   134195篇
  国内免费   5555篇
耳鼻咽喉   22729篇
儿科学   53094篇
妇产科学   48769篇
基础医学   242224篇
口腔科学   47876篇
临床医学   150558篇
内科学   346571篇
皮肤病学   39994篇
神经病学   138736篇
特种医学   65056篇
外国民族医学   527篇
外科学   260367篇
综合类   40374篇
现状与发展   3篇
一般理论   540篇
预防医学   124015篇
眼科学   39153篇
药学   123985篇
  2篇
中国医学   4918篇
肿瘤学   104001篇
  2021年   12861篇
  2019年   13704篇
  2018年   19917篇
  2017年   15143篇
  2016年   16838篇
  2015年   18954篇
  2014年   26797篇
  2013年   39006篇
  2012年   52968篇
  2011年   55599篇
  2010年   32832篇
  2009年   31423篇
  2008年   51427篇
  2007年   54720篇
  2006年   55217篇
  2005年   52911篇
  2004年   50447篇
  2003年   48236篇
  2002年   46495篇
  2001年   94357篇
  2000年   96661篇
  1999年   80107篇
  1998年   21226篇
  1997年   18787篇
  1996年   18539篇
  1995年   17501篇
  1994年   15847篇
  1993年   14770篇
  1992年   59039篇
  1991年   55761篇
  1990年   53365篇
  1989年   51430篇
  1988年   46927篇
  1987年   45601篇
  1986年   42363篇
  1985年   40202篇
  1984年   29831篇
  1983年   24862篇
  1982年   14496篇
  1981年   12678篇
  1979年   25538篇
  1978年   17519篇
  1977年   14740篇
  1976年   13345篇
  1975年   13974篇
  1974年   16724篇
  1973年   16092篇
  1972年   15188篇
  1971年   13955篇
  1970年   13198篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
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   
62.

Researchers have highlighted numerous sociocultural factors that have been shown to underpin human appearance enhancement practices, including the influence of peers, family, the media, and sexual objectification. Fewer scholars have approached appearance enhancement from an evolutionary perspective or considered how sociocultural factors interact with evolved psychology to produce appearance enhancement behavior. Following others, we argue that evidence from the field of evolutionary psychology can complement existing sociocultural models by yielding unique insight into the historical and cross-cultural ubiquity of competition over aspects of physical appearance to embody what is desired by potential mates. An evolutionary lens can help to make sense of reliable sex and individual differences that impact appearance enhancement, as well as the context-dependent nature of putative adaptations that function to increase physical attractiveness. In the current review, appearance enhancement is described as a self-promotion strategy used to enhance reproductive success by rendering oneself more attractive than rivals to mates, thereby increasing one’s mate value. The varied ways in which humans enhance their appearance are described, as well as the divergent tactics used by women and men to augment their appearance, which correspond to the preferences of opposite-sex mates in a heterosexual context. Evolutionarily relevant individual differences and contextual factors that vary predictably with appearance enhancement behavior are also discussed. The complementarity of sociocultural and evolutionary perspectives is emphasized and recommended avenues for future interdisciplinary research are provided for scholars interested in studying appearance enhancement behavior.

  相似文献   
63.
64.
65.
66.
67.
68.
69.
70.
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   
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