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   4001篇
  免费   161篇
  国内免费   39篇
耳鼻咽喉   13篇
儿科学   67篇
妇产科学   22篇
基础医学   408篇
口腔科学   133篇
临床医学   253篇
内科学   1106篇
皮肤病学   57篇
神经病学   188篇
特种医学   105篇
外科学   838篇
综合类   11篇
预防医学   113篇
眼科学   54篇
药学   354篇
中国医学   26篇
肿瘤学   453篇
  2023年   18篇
  2022年   47篇
  2021年   99篇
  2020年   34篇
  2019年   46篇
  2018年   68篇
  2017年   54篇
  2016年   79篇
  2015年   89篇
  2014年   96篇
  2013年   120篇
  2012年   176篇
  2011年   198篇
  2010年   130篇
  2009年   65篇
  2008年   171篇
  2007年   195篇
  2006年   178篇
  2005年   187篇
  2004年   165篇
  2003年   129篇
  2002年   139篇
  2001年   144篇
  2000年   146篇
  1999年   129篇
  1998年   47篇
  1997年   34篇
  1996年   36篇
  1995年   35篇
  1994年   17篇
  1993年   23篇
  1992年   84篇
  1991年   101篇
  1990年   88篇
  1989年   90篇
  1988年   95篇
  1987年   79篇
  1986年   78篇
  1985年   83篇
  1984年   42篇
  1983年   48篇
  1982年   23篇
  1981年   22篇
  1980年   24篇
  1979年   37篇
  1978年   22篇
  1977年   16篇
  1973年   22篇
  1970年   18篇
  1969年   25篇
排序方式: 共有4201条查询结果,搜索用时 15 毫秒
61.
Anomalous coronary arteries are usually identified incidentally by angiography or autopsy, but some "malignant" coronary anomalies are associated with a high incidence of syncope, arrhythmia, myocardial infarction, and sudden death. So far, the pathogenesis of the coronary events in such cases has only been revealed by autopsy. In the present case report, a patient with anomalous origin of the right coronary artery from the left sinus of Valsalva developed acute myocardial infarction, and visualization of the anomaly and assessment of the culprit plaque in the artery were done by multidetector row computed tomography and intravascular ultrasound.  相似文献   
62.
We evaluated the effect of a mucoactive agent (-)-(R)-2-amino-3-(3-hydroxypropylthio) propionic acid (fudosteine), on airway inflammation using endotoxin- and antigen-induced models. Time courses of growth related oncogene/cytokine-induced neutrophil chemoattractant-1 (GRO/CINC-1) production, neutrophil migration and goblet cell hyperplasia were examined in endotoxin-induced rat airway inflammation. GRO/CINC-1 in bronchoalveolar lavage fluid (BALF) increased in response to intratracheal instillation of endotoxin and peaked within 4 h. Neutrophils in BALF and goblet cells on trachea peaked 24 and 96 h after endotoxin instillation, respectively. Fudosteine significantly inhibited increases in GRO/CINC-1 at 10-100 mg/kg, and neutrophils and goblet cells at 30 and 100 mg/kg. These results suggest that inflammatory events including neutrophil chemoattractant production and neutrophil migration play important roles for goblet cell hyperplasia in endotoxin-induced airway inflammation, and fudosteine inhibits goblet cell hyperplasia by inhibiting GRO/CINC-1 production and/or neutrophil migration. Furthermore, fudosteine (100 mg/kg) inhibited ovalbumin-induced eosinophil infiltration into BALF, suggesting it attenuates asthmatic inflammation.  相似文献   
63.
64.
65.
Radish mosaic virus (RaMV) is a crucifer-infecting comovirus that has been detected worldwide. Here, we report the successful construction of a full-length infectious cDNA clone of RaMV. The full-length cDNA clones corresponding to RNA1 and RNA2 of a Japanese isolate of RaMV were cloned into the pBlueScript plasmid or the binary vector pCAMBIA1301 downstream of the cauliflower mosaic virus 35S promoter. Mechanical inoculation or agroinoculation of Nicotiana benthamiana with these vectors resulted in systemic RaMV infections causing symptoms similar to those caused by the wild-type parental virus. The presence of progeny virus was verified by western blot analysis and electron microscopy.  相似文献   
66.
Odontology - Oral scanners allow dental impressions to be taken in a short time without the use of an impression material. However, it has been noted that high impression accuracy cannot be...  相似文献   
67.
Radical scavenging activities are attractive properties not only for scientific fields e.g. biomedicine, but for the materials industry. In this study, we report that carbon nanotubes (CNTs) can scavenge radicals from organic peroxides, while radicals from azo-type radical initiators exhibit only a few effects from the presence of CNTs. In addition, experimental results suggest the possibility that captured peroxide radicals generate active radical sites on the CNT surface, from which polymerization can take place. These results indicate the importance of selecting an appropriate radical initiator.

Carbon nanotubes scavenge radicals preferentially from peroxides, and polymerization presumably takes place from generated active radical sites on the surface.  相似文献   
68.
69.
70.
Background Anti-platelet agents are widely used for the treatment and prevention of thrombotic diseases. On the other hand, continuation of anti-platelet agents increases the risk of hemorrhagic complications in gastrointestinal endoscopy, and cessation of anti-platelet agents exposes the patient to the risk of thromboembolism. Only a few studies have actually studied the whether a cessation period is required prior to endoscopic procedures and if so, the optional duration of the period. The present study assessed the time course of primary hemostasis after the cessation of anti-platelet agents.Methods Eleven healthy men (age range, 19–29 years) were assigned to each of the following regimens: aspirin (ASA; 100 mg/day), ticlopidine (TP; 300 mg/day), and a combination of ASA (100 mg/day) and TP (300 mg/day) for 7 days. There was a washout period of more than 3 weeks between each regimen. A quantitative bleeding time test (QBT test) and platelet aggregation test were performed before the beginning of administration, on the last day of administration, and at 1, 3, and 5 days after cessation, and also at 7 days after cessation for the combination regimen.Results The average bleeding time (BT) and total bleeding loss volume (Tv) of the 11 subjects after administration of the three regimens were significantly increased compared with those before administration. With the administration of ASA, increases of BT and Tv at 3 days after cessation were not significant. The Tv at 5 days after cessation of TP was not significantly increased. With the combination regimen, the BT and Tv at 7 days after cessation were not significantly increased.Conclusions A 3-day cessation period for ASA, a 5-day cessation period for TP, and a 7-day cessation period for ASA + TP administration seem to be sufficient.  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