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   7862篇
  免费   419篇
  国内免费   100篇
耳鼻咽喉   19篇
儿科学   18篇
妇产科学   43篇
基础医学   366篇
口腔科学   257篇
临床医学   382篇
内科学   1931篇
皮肤病学   11篇
神经病学   335篇
特种医学   161篇
外科学   170篇
综合类   664篇
预防医学   859篇
眼科学   63篇
药学   2331篇
中国医学   708篇
肿瘤学   63篇
  2023年   58篇
  2022年   101篇
  2021年   128篇
  2020年   150篇
  2019年   120篇
  2018年   152篇
  2017年   136篇
  2016年   165篇
  2015年   199篇
  2014年   438篇
  2013年   440篇
  2012年   469篇
  2011年   565篇
  2010年   440篇
  2009年   382篇
  2008年   400篇
  2007年   412篇
  2006年   327篇
  2005年   248篇
  2004年   223篇
  2003年   219篇
  2002年   179篇
  2001年   185篇
  2000年   160篇
  1999年   164篇
  1998年   175篇
  1997年   136篇
  1996年   136篇
  1995年   130篇
  1994年   108篇
  1993年   121篇
  1992年   106篇
  1991年   90篇
  1990年   49篇
  1989年   39篇
  1988年   39篇
  1987年   30篇
  1986年   30篇
  1985年   130篇
  1984年   90篇
  1983年   45篇
  1982年   55篇
  1981年   59篇
  1980年   62篇
  1979年   65篇
  1978年   39篇
  1977年   33篇
  1976年   44篇
  1975年   30篇
  1974年   30篇
排序方式: 共有8381条查询结果,搜索用时 0 毫秒
1.
Methanol poisoning is often described in the literature, but not transdermal or inhalational poisoning. It usually involves variable multi-organ damage, among which visual, neurological, and gastrointestinal involvement, as well as the metabolic and electrolyte changes that can lead to death. Contact with toluene by occupational or intentional inhalation may also cause neurological abnormalities. This article describes the case of a female patient who was seen in the Emergency Department due to bilateral visual loss secondary to accidental poisoning (inhalation-transdermal) with a solvent containing methanol and toluene. She had a favourable outcome during admission after treatment with ethanol in perfusion and corticosteroids.  相似文献   
2.
本文综述了近10年来黄栌中漆黄索的提取工艺和测定方法的研究进展,并对各种提取工艺和测定方法进行了评价。为更好地开发利用漆黄素提供参考。  相似文献   
3.
目的:优选散结消肿贴中大黄、重楼的渗漉提取工艺。方法:以总固体物得率和总蒽醌得率为指标,用正交实验优选。结果:工艺中影响最大的因素是乙醇浓度,其次是乙醇用量,浸泡时间影响较小。最佳工艺条件为乙醇浓度65%,乙醇用量8倍量。浸泡时间24h。结论:渗漉法操作简单,成份破坏少,用优选所得条件进行提取,总蒽醌和总固体物得率均较高,优选结果可用于散结消肿贴中大黄、重楼的提取。  相似文献   
4.
5.
甘草黄酮的提取分离和含量测定   总被引:21,自引:0,他引:21  
目的:充分利用甘草资源。方法:从提取过甘草酸的废渣中提取甘草黄酮并进行含量测定。结果:用碱酸处理和用大孔树脂处理黄酮含量高,收率也高。结论:从甘草废渣中提取甘草黄酮具有较好的社会效益和经济效益  相似文献   
6.
A series of experiments evaluated the determinants of preference for mixtures of ethanol plus sucrose relative to sucrose in rats. One dipper served 10% ethanol mixed with 10% sucrose, and the second dipper served 10% sucrose. Lever presses operated each dipper according to a variable-interval 5-s schedule. In three experiments the subjects were given pre-session meals of sucrose (2.5–20 ml) or sucrose (20 ml) plus chow (5 or 10 g). Pre-session meals decreased responding maintained by sucrose but not responding maintained by ethanol mixture. In two experiments body weight was varied from 85% to 125% of the initial free-feeding values. Increases in body weight, like pre-session meals, decreased responding reinforced by sucrose, but typically did not decrease responding reinforced by ethanol mixture. Throughout most of the study, ethanol consumption remained at about 1.25 ml per half hour session (3–4 g/kg per 30 min). For example, pre-session access to ethanol mixture decreased within-session ethanol consumption, but total consumption, counting both sources, remained about 1.25 ml/session. The within-session patterns of responding also differed. Responding reinforced by ethanol mix decreased as a function of ethanol consumption, whereas responding reinforced by sucrose was relatively constant throughout the session. The simplest explanation of the results is that ethanol's pharmacological consequences regulated preference.  相似文献   
7.
Cocaethylene, a psychoactive metabolite resulting from combined ethanol/cocaine consumption, is of interest because its psychostimulant properties may partially underlie combined cocaine/ethanol use, and because it has the potential for use as a probe of drug reward mechanisms due to its enhanced selectivity at monoamine uptake sites compared to cocaine. To determine the relative systemic bioavailabilities of cocaine and cocaethylene, sequential plasma samples were obtained from awake rats following drug administration. Following intravenous administration of 3 µmol/kg (molar equivalent of 1 mg/kg cocaine-HCl), both drugs achieved similar time courses and areas under the plasma concentration versus time curve. In contrast, intraperitoneal administration of 44 µmol/kg (molar equivalent of 15 mg/kg cocaine HCl) showed peak plasma levels, and the area under the plasma concentration vs time curve for cocaine to be approximately twice that for cocaethylene. Comparison of dose corrected areas under the curve of the two routes of administration for each drug indicated that relative systemic bioavailability of cocaethylene following intraperitoneal administration is only 58% that of cocaine. In addition, the elimination of both cocaine and cocaethylene was found to be slower following intraperitoneal administration compared to the intravenous route. The implications of these results are discussed with respect to the relative potency of these two compounds, as inferred from behavioral, drug reward, and lethality studies. Also, the differences noted will need to be taken into account when making mechanistic interpretations from comparative drug reward studies.  相似文献   
8.
Previous work has reported that the 5-hydroxytryptamine (5-HT)1A agonist, 8-hydroxy 2-(di-n-propylamino)tetralin (8-OH DPAT), reduces ethanol intake by rats. However, as 8-OH DPAT reduces 5-HT neurotransmission, these findings are inconsistent with the proposed inhibitory role of central 5-HT neurons on ethanol intake. We examined the effect of 8-OH DPAT on ethanol, water and food intake in rats maintained on a limited access schedule using a lower dose range (6–250 µg/kg) and by assessing concomitant changes in behaviour. Low doses of 8-OH DPAT enhanced ethanol intake even when food and water were offered as alternatives. Suppression in ethanol intake was observed at higher doses where elements of the 5-HT syndrome were apparent. Similar observations were made in both fluid and non-fluid deprived water drinking rats, suggesting the latter effect is non-selective. Therefore 8-OH DPAT may both increase or decrease ethanol consumption in the rat depending on the dose used.  相似文献   
9.
Our previous work on a social insect model of ethanol-induced behavior focused on behavioral studies of honeybees (Apis mellifera L.). We now investigate the dependence of honeybee blood ethanol concentration on both the amount of ethanol consumed and time elapsed since ingestion. Blood ethanol level was determined using gas chromatograph using hemolymph taken from harnessed bees. Significantly increased levels of ethanol in honeybee hemolymph were detected within 15 min of feeding bees alcohol. Within 30 min, ethanol concentration increased 2.7 times. The concentration of ethanol ingested also had a significant effect on blood ethanol level. However, postfeeding times greater than 30 min did not significantly increase ethanol concentration in bee hemolymph. This study integrates with our behavioral data on the effect of ethanol on honeybees. Our laboratory and field experiments show a correlation between the time frame for behavioral changes and significant increases of blood ethanol levels shown in this study.  相似文献   
10.
周小兵 《中外医疗》2009,28(34):185-185
目的吸取误诊教训,提高对茎突综合征诊断水平。方法回顾性分析3例茎突综合征误诊的临床资料。结果找出误诊原因,并借助文献进行分析、讨论。结论要熟悉茎突综合征的病因,临床特点和并发症,提高警惕性,发现可茎突综合征病人,及时做医学影像检查和咽部触诊。  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