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   391篇
  免费   29篇
  国内免费   5篇
耳鼻咽喉   1篇
儿科学   25篇
妇产科学   3篇
基础医学   36篇
口腔科学   30篇
临床医学   52篇
内科学   64篇
皮肤病学   5篇
神经病学   18篇
特种医学   61篇
外科学   28篇
综合类   28篇
预防医学   18篇
药学   33篇
中国医学   4篇
肿瘤学   19篇
  2023年   1篇
  2022年   1篇
  2021年   9篇
  2020年   5篇
  2019年   3篇
  2018年   4篇
  2017年   8篇
  2016年   6篇
  2015年   10篇
  2014年   7篇
  2013年   17篇
  2012年   20篇
  2011年   13篇
  2010年   27篇
  2009年   14篇
  2008年   11篇
  2007年   8篇
  2006年   9篇
  2005年   13篇
  2004年   8篇
  2003年   4篇
  2002年   5篇
  2001年   3篇
  2000年   6篇
  1999年   10篇
  1998年   23篇
  1997年   14篇
  1996年   20篇
  1995年   8篇
  1994年   14篇
  1993年   11篇
  1992年   3篇
  1991年   9篇
  1990年   6篇
  1989年   12篇
  1988年   12篇
  1987年   15篇
  1986年   10篇
  1985年   6篇
  1984年   6篇
  1983年   3篇
  1982年   8篇
  1981年   2篇
  1980年   5篇
  1979年   1篇
  1978年   1篇
  1977年   3篇
  1976年   7篇
  1975年   2篇
  1971年   2篇
排序方式: 共有425条查询结果,搜索用时 109 毫秒
11.
目的:探讨皮质醇增多症的临床表现和内分泌检查等辅助检查的意义.方法:从年龄、性别、病程及实验室检查等方面,观察22例不同原因所致皮质醇增多症患者不同的临床表现和测定实验室检查指标.结果:22例中诊断库欣病(增生型)14例[63.6%,其中13例(92.9%)得到MRI检查证实],肾上腺腺瘤6例[27.3%,均得到MRI检查证实(100%)],另有肾上腺结节样增生1例(4.5%),异位ACTH综合征1例(4.5%).临床表现:按出现的频率前4位依次为,库欣病:高血压(100%)、满月脸(92.9%)、向心性肥胖(85.7%)、多血质(85.7%),肾上腺腺瘤:高血压(100%)、满月脸(100%)、向心性肥胖(100%)、多血质(83.3%).实验室检查:小剂量地塞米松不能抑制:库欣病与肾上腺腺瘤均为100%.结论:根据高血压、满月脸、向心性肥胖,小剂量地塞米松抑制试验和MRI检查可诊断绝大多数皮质醇增多症.  相似文献   
12.
Background and purpose: In chronic diseases including Parkinson’s disease (PD), complex pharmacotherapy dosing schedules are reported to reduce adherence, perhaps leading to less‐effective symptom control and, in PD, more erratic stimulation of dopamine receptors. However, blinded clinical‐trial designs preclude direct comparisons of adherence to various schedules. Methods: In two double‐blind (DB) studies of early PD and one of advanced PD, subjects received three‐times‐daily (t.i.d.) pramipexole or placebo. In open‐label (OL) extensions, subjects took extended‐release, once‐daily (q.d.) pramipexole. At 24 or 32 OL weeks, q.d. versus t.i.d. dosing preference was surveyed by questionnaire. Results: Of 590 DB‐trial completers with early PD, 511 entered the OL extension. Of 374 survey respondents, 94.4% preferred q.d. dosing (72.2% of them found it ‘very much more convenient’ and 27.8%‘more convenient’), 2.7% preferred t.i.d., and 2.9% chose ‘no difference’. Of 465 DB‐trial completers with advanced PD, 391 entered its OL extension. Of 334 survey respondents, 88.9% preferred q.d. dosing (59.9% of them found it ‘very much more convenient’ and 40.1%‘more convenient’), 5.7% preferred t.i.d., and 5.4% chose ‘no difference’. Results excluding DB‐placebo recipients were highly similar. Conclusions: In this first direct comparison of patient preference for q.d. versus t.i.d. dopamine‐agonist dosing, patients with early or advanced PD had a strong preference for q.d. rather than t.i.d. pramipexole. The high proportion of advanced‐PD patients declaring this preference indicates that it does not depend on whether a patient is taking concomitant PD medications dosed more frequently than q.d.  相似文献   
13.
14.

Rationale

Although non-medical use of oxycodone continues to be a growing problem in the United States, there are no animal studies examining the effects of long-term oxycodone self-administration (SA).

Objectives

The current study was designed to examine chronic oxycodone SA by mice (14 days), in novel extended (4 h) SA sessions and its effect on selective striatal neurotransmitter receptor mRNA expression.

Methods

Adult male C57/BL6J mice were either allowed to self-administer oxycodone (0.25 mg/kg/infusion, FR1) or served as yoked-saline controls in an extended access paradigm. Mice self-administered oxycodone for 4 h/day for 14 consecutive days. Comparison groups with 14-days exposure to 1-h SA sessions were also studied. Within 1 h of the last extended SA session, mice were sacrificed, dorsal striatum was isolated and selective neurotransmitter receptor mRNA levels were examined.

Results

The oxycodone groups poked the active hole significantly more times than the yoked controls. The number of nose pokes at the active hole rose over the 14 days in the oxycodone group with extended access. The expression of 13 neurotransmitter receptor mRNAs was significantly altered in the dorsal striatum, including the gamma-aminobutyric acid (GABA) A receptor beta 2 subunit (Gabrb2) showing experiment-wise significant decrease, as a result of extended oxycodone SA.

Conclusion

C57BL/6 J mice escalated the amount of oxycodone self-administered across 14 consecutive daily extended sessions, but not 1-h sessions. Decreases in Gabrb2 mRNA levels may underlie escalation of oxycodone intake in the extended access SA sessions.  相似文献   
15.
Porter  JB; Hoyes  KP; Abeysinghe  RD; Brooks  PN; Huehns  ER; Hider  RC 《Blood》1991,78(10):2727-2734
Five orally effective iron chelators of the 3-hydroxypyridin-4-one series have been administered intraperitoneally to iron-overloaded and nonoverloaded male mice at a dose of 200 mg/kg/24 h for a total of 60 days to investigate the effect on iron loading and toxicity. There was a significant reduction in hepatic iron at the end of the study in the iron-overloaded mice with all compounds studied using chemical iron quantitation (P less than .001) and with Perls' stain (P less than .01). Liver iron removal with the hydroxypyridinones ranged from 37% with CP20 to 63% with CP51, compared with 46% removal for desferrioxamine (DFO). There was no significant reduction in splenic or cardiac iron with any chelator. There were no deaths in iron-overloaded animals receiving any of the hydroxypyridin-4-ones, but significantly more deaths in the nonoverloaded groups as a whole (P less than .03). No weight loss was observed with any chelator. Significant reductions in hemoglobin and white cell count were observed with CP20(L1). No histologic abnormalities of kidney, spleen, bone marrow, or stifle joints were observed. Intracytoplasmic inclusion bodies were observed in the centrilobular hepatocytes of animals administered each of the hydroxypyridin-4-ones, while the DFO-treated and control groups showed no such changes.  相似文献   
16.
Individuals with high-level spinal cord injury (SCI) experience low blood pressure (BP) and cognitive impairments. Such dysfunction may be mediated in part by impaired neurovascular coupling (NVC) (i.e., cerebral blood flow responses to neurologic demand). Ten individuals with SCI >T6 spinal segment, and 10 age- and sex-matched controls were assessed for beat-by-beat BP, as well as middle and posterior cerebral artery blood flow velocity (MCAv, PCAv) in response to a NVC test. Tests were repeated in SCI after 10 mg midodrine (alpha1-agonist). Verbal fluency was measured before and after midodrine in SCI, and in the control group as an index of cognitive function. At rest, mean BP was lower in SCI (70±10 versus 92±14 mm Hg; P<0.05); however, PCAv conductance was higher (0.56±0.13 versus 0.39±0.15 cm/second/mm Hg; P<0.05). Controls exhibited a 20% increase in PCAv during cognition; however, the response in SCI was completely absent (P<0.01). When BP was increased with midodrine, NVC was improved 70% in SCI, which was reflected by a 13% improved cognitive function (P<0.05). Improvements in BP were related to improved cognitive function in those with SCI (r2=0.52; P<0.05). Impaired NVC, secondary to low BP, may partially mediate reduced cognitive function in individuals with high-level SCI.  相似文献   
17.
目的:了解进展较快的食管和贲门癌前病变的时间,为寻找合适的筛查间隔提供线索.方法:在食管癌高发区河北涉县对40~69岁人群开展重复的内镜筛查.结果:301例重复筛查共观察到40例病情发生进展者,其中7例重度不典型增生中:1例首检为正常,间隔13个月检出重度不典型增生,1例首检为基底细胞增生,间隔7个月检出,4例首检为轻度不典型增生,分别间隔3个月、4个月、4个月、10.5个月检出,1例首检为中度不典型增生,间隔12.5个月检出;6例原位癌及黏膜内癌中:1例首检为轻度不典型增生,间隔48个月检出,2例中度不典型增生分别间隔4个月、13个月检出2例,3例重度不典型增生分别间隔3.5个月、9个月、17.5个月检出;3例浸润性癌中:1例中度不典型增生,间隔50个月检出、2例重度不典型增生间隔14个月和19个月检出.结论:食管和贲门癌前病变的滞留时间变异较大,有必要适当缩短筛查间隔,通过及时复查捕获那些进展较快、多点起源和首检遗漏的癌前病变.  相似文献   
18.
19.
20.
目的研究复苏因子蛋白对休眠结核杆菌的复苏作用,探索对休眠结核杆菌的最佳复苏方案。方法应用含不同浓度复苏因子蛋白的7H9液体培养基培养休眠结核杆菌H37Rv,分别在第6天、第11天、第16天、第30天检测培养物的OD值、并取10μL培养液涂于7H11平板培养、抗酸染色。结果低浓度组合有最佳复苏效果,高浓度复苏因子组合抑制体眠结核菌复苏。低浓度复苏因子A和高、低浓度的复苏因子B、C、E均有不同程度的复苏促进作用,复苏因子D和高浓度的复苏因子A均无复苏作用。重复试验结果相同。结论结核杆菌复苏因子蛋白对结核杆菌有复苏促进作用。  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