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   274篇
  免费   18篇
  国内免费   78篇
儿科学   2篇
妇产科学   4篇
基础医学   21篇
口腔科学   2篇
临床医学   57篇
内科学   47篇
神经病学   54篇
特种医学   7篇
外科学   12篇
综合类   21篇
预防医学   10篇
眼科学   9篇
药学   112篇
中国医学   2篇
肿瘤学   10篇
  2023年   3篇
  2022年   1篇
  2021年   4篇
  2020年   1篇
  2019年   5篇
  2018年   2篇
  2017年   4篇
  2016年   6篇
  2015年   7篇
  2014年   12篇
  2013年   12篇
  2012年   9篇
  2011年   13篇
  2010年   8篇
  2009年   8篇
  2008年   7篇
  2007年   54篇
  2006年   23篇
  2005年   25篇
  2004年   11篇
  2003年   7篇
  2002年   10篇
  2001年   10篇
  2000年   5篇
  1999年   7篇
  1998年   6篇
  1997年   15篇
  1996年   11篇
  1995年   9篇
  1994年   7篇
  1993年   9篇
  1992年   9篇
  1991年   5篇
  1990年   8篇
  1989年   5篇
  1988年   5篇
  1987年   2篇
  1986年   3篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1982年   4篇
  1981年   3篇
  1980年   1篇
  1979年   2篇
  1978年   3篇
  1977年   1篇
  1975年   1篇
  1974年   1篇
排序方式: 共有370条查询结果,搜索用时 15 毫秒
61.
62.

Objective

To explore the relationship between weather phenomena and pollution levels and daily hospital admissions (as an approximation to morbidity patterns) in Hong Kong Special Administrative Region (SAR), China, in 1998–2009.

Methods

Generalized additive models and lag models were constructed with data from official sources on hospital admissions and on mean daily temperature, mean daily wind speed, mean relative humidity, daily total global solar radiation, total daily rainfall and daily pollution levels.

Findings

During the hot season, admissions increased by 4.5% for every increase of 1 °C above 29 °C; during the cold season, admissions increased by 1.4% for every decrease of 1 °C within the 8.2–26.9 °C range. In subgroup analyses, admissions for respiratory and infectious diseases increased during extreme heat and cold, but cardiovascular disease admissions increased only during cold temperatures. For every increase of 1 °C above 29 °C, admissions for unintentional injuries increased by 1.9%. During the cold season, for every decrease of 1 °C within the 8.2–26.9 °C range, admissions for cardiovascular diseases and intentional injuries rose by 2.1% and 2.4%, respectively. Admission patterns were not sensitive to sex. Admissions for respiratory diseases rose during hot and cold temperatures among children but only during cold temperatures among the elderly. In people aged 75 years or older, admissions for infectious diseases rose during both temperature extremes.

Conclusion

In Hong Kong SAR, hospitalizations rise during extreme temperatures. Public health interventions should be developed to protect children, the elderly and other vulnerable groups from excessive heat and cold.  相似文献   
63.
RATIONALE AND OBJECTIVES: The mechanisms underlying relapse to cocaine seeking induced by exposure to priming cocaine injections, cues associated with cocaine self-administration and environmental stressors have been studied in rats. Here we describe a reinstatement method for studying relapse to cocaine seeking in mice, a suitable species for studying the effect of genetic manipulations such as gene knockout or gene over-expression on compulsive drug use.METHODS: Male mice of the 129X1/SvJ strain were trained for 14-16 days to self-administer cocaine (0.75 mg/kg/infusion; 4 h/day; fixed-ratio-1 schedule of reinforcement; infusions were paired with a light-tone compound cue). Next, the lever-pressing behavior was extinguished by removing the cocaine syringes in the presence (Exps. 1 and 3) or absence (Exp. 2) of the cocaine cue. Subsequently, tests for reinstatement were conducted after exposure to priming injections of cocaine (0, 1.5, 3.0 and 6.0 mg/kg, IV; Exp. 1), response-contingent presentations of the cocaine-associated cue (Exp. 2), or food deprivation stress (1 and 22 h; Exp. 3).RESULTS: The effect of cocaine priming on reinstatement was modest and was only observed at the highest dose tested. On the other hand, reinstatement of cocaine seeking was observed following exposure to the cocaine-associated cue and food deprivation stress.CONCLUSIONS: The present data suggest that factors contributing to relapse to drugs can be studied in the reinstatement model using the common 129X1/SvJ mouse inbred strain.  相似文献   
64.
海风藤中有PAF拮抗活性的苯骈呋喃类新木脂素   总被引:5,自引:0,他引:5  
马迎  韩桂秋  王银叶 《药学学报》1993,28(5):370-373
自福建产中药海风藤(Piper kadsura (Choisy)Ohwi)的藤茎中又分得5个苯骈呋喃类新木脂素,经光谱分析(UV,IR,MS,NMR,CD)和衍生物制备,确定化合物Ⅱ和Ⅴ为新结构。Ⅱ为化合物denudatin B的对映体,命名为(-)-denudatin B,V为7S,8S-3,4,3′-三甲氧基-7′-氧-缺8′,9′-7.O.4,′8.5′-新木脂素,命名为风藤素M(kadsurenin M)。化合物Ⅰ,Ⅲ和Ⅳ分别为已知化合物海风藤酮(Ⅰ),(-)-acuminatin(Ⅲ)和(+)-licarin A(Ⅳ)。PAF受体结合实验证明,(-)-denudatin B也具有较强的PAF拮抗活性。  相似文献   
65.
The elbow: MR features of nerve disorders   总被引:3,自引:0,他引:3  
  相似文献   
66.
BACKGROUND: Brain noradrenaline is involved in footshock stress-induced reinstatement of drug seeking in a rat relapse model. We studied whether yohimbine, an alpha-2 adrenoceptor antagonist that increases noradrenaline release and induces anxiety-like responses in human and nonhuman subjects, would reinstate methamphetamine seeking in rats. METHODS: In experiment 1, the effect of yohimbine (1.25-2.5 mg/kg) on reinstatement was compared with that of intermittent footshock (5 min;.2-.6 mA) in rats that were trained to lever press for intravenous methamphetamine (9-11 days) and subsequently underwent 7 days of extinction training. In experiment 2, the effect of yohimbine on reinstatement of drug seeking was determined during early (1 day) and late (21 or 51 days) withdrawal periods. On the test days, rats were first given 3-hour extinction sessions and were then tested for reinstatement induced by yohimbine. RESULTS: In experiment 1, both yohimbine and footshock stress reinstated methamphetamine seeking after extinction. In experiment 2, extinction responding was higher after 21 or 51 withdrawal days than after 1 withdrawal day. In contrast, no significant time-dependent changes in yohimbine-induced reinstatement were observed. CONCLUSIONS: Results indicate that yohimbine is a potent stimulus for reinstatement of methamphetamine seeking in a rat relapse model.  相似文献   
67.
BACKGROUND: Three reported Swedish cases of hepatitis C in patients receiving an intravenous immunoglobulin (Gammagard, Baxter Healthcare, Deerfield, IL) were among the first to bring to light a worldwide outbreak of hepatitis C associated with non-solvent/detergent (SD)- treated Gammagard. In February 1994, all implicated batches of Gammagard were recalled and exposed patients traced. STUDY DESIGN AND METHODS: Sera from all identified and hepatitis C-viremic Swedish and Danish patients (n = 14) exposed to the implicated batches underwent hepatitis C virus genotyping and sequencing of the core region and hypervariable region 1 of E2. Genomic amplification was also done on 15 non-SD-treated batches of Gammagard. RESULTS: Twelve patients were infected with subtype 1a and surprisingly, two with subtype 2b. Analysis of the core region showed identical sequences in four patients and the only consistently positive batch. Five patients shared another sequence, whereas three other subtype 1a patients each manifested unique sequences. The two subtype 2b isolates were identical. Genomic fingerprinting of the hypervariable region confirmed identity within each group with great stringency. Amplification with isolate-specific primers showed mixed infection in one patient whose exposure was confined to a single batch. CONCLUSION: The few batches implicated presumably were contaminated with several strains.  相似文献   
68.
裴林  纵艳艳  孙亚锋  张光毅 《药学学报》1996,31(11):812-816
以体外培养的大鼠胚胎皮层神经元为对象,以培养上清液中乳酸脱氢酶活性为指标,研究了谷氨酸兴奋毒性及药物的保护作用。结果表明,培养10d的皮层神经元置于含10或50μmol·L-1谷氨酸和低糖(1g·L-1)的DMEM培养液中后,随着作用时间的延长,LDH漏出逐渐增加。在谷氨酸处理前,于培养液中加入氯胺酮或硝苯吡啶,则LDH漏出量明显低于对照组。氯胺酮和硝苯吡啶并用,LDH漏出量比单独使用氯胺酮或硝苯吡啶下降更加明显。结果表明,谷氨酸对培养的神经元可产生严重损伤。氯胺酮和硝苯吡啶单用或并用均有明显的保护作用。  相似文献   
69.
咪苯嗪酮(CI-914)能抑制大鼠血小板环氧酶和TXA2合成酶产物HHT的生成,而对脂氧酶产物12-HETE的生成仅高浓度药物才有弱的抑制作用,提示CI-914主要影响花生四烯酸(AA)环氧酶途径,而对脂氧酶途径影响较少。在大鼠血小板和中性白细胞CI-914能抑制TXA2的生成,同时CI-914还可使白细胞6-keto-PGF1a和血小板PGE2的产生量显著增加,提示CI-914在这两种细胞引起了AA的转向合成。上述结果基本证实,CI-914在大鼠中性白细胞和血小板对TXA2合成酶具有选择性抑制作用。  相似文献   
70.
脑益嗪对实验性脑血栓形成及血小板聚集的抑制作用   总被引:17,自引:0,他引:17  
本文报道脑益嗪对大鼠实验性脑血栓形成及兔血小板聚集的抑制作用。经大鼠颈动脉顺行注射复合血栓诱导剂造成脑血栓模型,测定伊文思兰通过血脑屏障渗入脑实质的量以反映脑血栓的严重程度。结果表明脑益嗪(67 mg/kg,灌胃)有抗脑血栓形成的作用。半体内实验表明脑益嗪(34 mg/kg,灌胃)可抑制兔血小板聚集。  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