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   184174篇
  免费   34564篇
  国内免费   4912篇
耳鼻咽喉   5358篇
儿科学   5829篇
妇产科学   2768篇
基础医学   7257篇
口腔科学   2116篇
临床医学   30958篇
内科学   52377篇
皮肤病学   7714篇
神经病学   16199篇
特种医学   7439篇
外国民族医学   29篇
外科学   44478篇
综合类   6217篇
现状与发展   81篇
一般理论   3篇
预防医学   9379篇
眼科学   4243篇
药学   4651篇
  32篇
中国医学   2017篇
肿瘤学   14505篇
  2024年   845篇
  2023年   5433篇
  2022年   2844篇
  2021年   5158篇
  2020年   7438篇
  2019年   3384篇
  2018年   8566篇
  2017年   8424篇
  2016年   9405篇
  2015年   9908篇
  2014年   17358篇
  2013年   17289篇
  2012年   7891篇
  2011年   8185篇
  2010年   12007篇
  2009年   15526篇
  2008年   7422篇
  2007年   5762篇
  2006年   8086篇
  2005年   5299篇
  2004年   4103篇
  2003年   3045篇
  2002年   2975篇
  2001年   4567篇
  2000年   3757篇
  1999年   3968篇
  1998年   4085篇
  1997年   3920篇
  1996年   3705篇
  1995年   3542篇
  1994年   2262篇
  1993年   1740篇
  1992年   1603篇
  1991年   1630篇
  1990年   1293篇
  1989年   1365篇
  1988年   1169篇
  1987年   973篇
  1986年   1003篇
  1985年   807篇
  1984年   617篇
  1983年   556篇
  1982年   538篇
  1981年   421篇
  1980年   372篇
  1979年   329篇
  1978年   342篇
  1977年   414篇
  1975年   294篇
  1972年   318篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
BACKGROUND: Residual blood flow around thrombus prior to treatment predicts success of coronary thrombolysis. The authors aimed to correlate the presence of residual flow signals in the middle cerebral artery (MCA) with completeness of recanalization after intravenous tissue plasminogen activator (TPA). METHODS: The authors studied consecutive patients treated with intravenous TPA therapy who had a proximal MCA occlusion on pretreatment transcranial Doppler (TCD). Patients were continuously monitored for 2 hours after TPA bolus. Absent residual flow signals correspond to the thrombolysis in brain ischemia (TIBI) 0 grade, and the presence of residual flow signals was determined as TIBI 1-3 flow grades. Complete recanalization was defined as flow improvement to TIBI grades 4-5. RESULTS: Seventy-five patients with a proximal MCA occlusion had median pre-bolus NIHSS 16 (85% with > or = 10 points). TPA bolus was given at 141 +/- 56 minutes (median 120 minutes). Complete recanalization was observed in 25 (33%), partial in 23 (31%), and no early recanalization was seen in 27 (36%) patients within 2 hours after TPA bolus. Only 19% with absent residual flow signals (TIBI grade 0, n = 26) on pretreatment TCD had complete early recanalization. If pretreatment TCD showed the presence of any residual flow (TIBI 1-3, n = 49), 41% had complete recanalization within 2 hours of TPA bolus (P = .03). CONCLUSIONS: Patients with detectable residual flow signals before IV TPA bolus are twice as likely to have early complete recanalization. Those with no detectable residual flow signals have less than 20% chance for complete early recanalization with intravenous TPA and may be candidates for intra-arterial therapies.  相似文献   
992.
A retrospective study was performed to compare intravenous lorazepam and intravenous diazepam in the treatment of status epilepticus. Forty-five episodes of status epilepticus in children between the ages of 2 weeks and 18 years were reviewed. Lorazepam and diazepam proved similar in efficacy of seizure control and incidence of adverse effects. The dose of lorazepam required to control status epilepticus ranged from 0.03 to 0.22 mg/kg with a mean of 0.11 mg/kg (S.D. = 0.05 mg/kg). Among children treated with lorazepam, only children younger than 2 years of age had respiratory depression which required intubation.  相似文献   
993.
994.
Development of a new wound dressing with antimicrobial delivery capability   总被引:1,自引:0,他引:1  
A bilaminar wound dressing composed of an outer membrane and an inner three-dimensional matrix of a fabric or a sponge may be considered to constitute an ideal structure that promotes wound healing: the outer membrane prevents body fluid loss, controls water evaporation, and protects the wound surface from bacterial invasion, and the inner matrix encourages adherence by tissue growth into the matrix. Using this concept, we developed a biosynthetic wound dressing with a drug delivery capability. This medicated wound dressing is composed of a spongy sheet of a chitosane derivative and collagen mixture that is laminated to an antimicrobial-impregnated polyurethane membrane. In this study, a gentamycin sulfate-impregnated wound dressing was prepared and evaluated. The antimicrobial efficacy of this wound dressing was examined on an agar plate seeded with Pseudomonas aeruginosa. Also, the cytotoxicity of an antimicrobial released from this wound dressing was examined in an in vitro system with cultured skin substitutes. Both in vitro tests have shown that this wound dressing is capable of suppressing bacterial growth and minimizing cellular damage. In addition, in the treatment of wounds inflicted on rats and rabbits, this wound dressing was shown to be efficacious in covering full-thickness and split-thickness skin defects. Finally, the efficacy of this wound dressing was evaluated in a nonrandomized open-label study of 31 clinical cases. In 31 cases treated with this wound dressing, good or excellent wound healing was achieved.  相似文献   
995.
996.
997.
The biliary excretion of radioactivity after intravenous [3H]25-hydroxyvitamin D3 was studied in nine patients with T-tube bile drainage. The mean +/- SD 24-hr radioactivity excretion in T-tube bile expressed as a percentage of the administered dose was 6.7 +/- 2.9%; after correction for incomplete bile collection, the value obtained was 16.0 +/- 11.1%. Chloroform solubility of biliary radioactivity increased from 27.4 +/- 8.9% to 72.9 +/- 10.1% following incubation with beta-glucuronidase. High-performance liquid chromatographic analysis of chloroform extracts of bile revealed that most of the eluted radioactivity was more polar than [3H]25-hydroxyvitamin D3. No free [3H]25-hydroxyvitamin D3 was demonstrated. Thus in man, most of the biliary radioactivity excreted following [3H]25-hydroxyvitamin D3 is in the form of water-soluble compounds, mainly glucuronides. However, our results suggest that glucuronides of metabolites other than 25-OHD3 are predominantly formed.  相似文献   
998.
999.
1000.
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