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   2555篇
  免费   171篇
  国内免费   10篇
耳鼻咽喉   35篇
儿科学   67篇
妇产科学   92篇
基础医学   377篇
口腔科学   71篇
临床医学   189篇
内科学   611篇
皮肤病学   98篇
神经病学   253篇
特种医学   100篇
外科学   208篇
综合类   7篇
一般理论   1篇
预防医学   270篇
眼科学   20篇
药学   191篇
中国医学   16篇
肿瘤学   130篇
  2023年   27篇
  2022年   39篇
  2021年   118篇
  2020年   59篇
  2019年   86篇
  2018年   119篇
  2017年   72篇
  2016年   64篇
  2015年   79篇
  2014年   95篇
  2013年   115篇
  2012年   189篇
  2011年   176篇
  2010年   98篇
  2009年   88篇
  2008年   126篇
  2007年   151篇
  2006年   140篇
  2005年   139篇
  2004年   131篇
  2003年   119篇
  2002年   94篇
  2001年   32篇
  2000年   31篇
  1999年   23篇
  1998年   15篇
  1997年   13篇
  1996年   16篇
  1995年   19篇
  1994年   9篇
  1993年   5篇
  1992年   21篇
  1991年   21篇
  1990年   14篇
  1989年   22篇
  1988年   12篇
  1987年   10篇
  1986年   15篇
  1985年   16篇
  1984年   14篇
  1983年   12篇
  1982年   5篇
  1979年   6篇
  1978年   8篇
  1977年   8篇
  1976年   5篇
  1974年   9篇
  1970年   8篇
  1968年   7篇
  1967年   4篇
排序方式: 共有2736条查询结果,搜索用时 15 毫秒
131.
Metabolic Brain Disease - Worldwide, the excessive consumption of fat and/or sugar has increased considerably. Palatable high-fat diets (HFDs) lead to metabolic disturbances and obesity,...  相似文献   
132.
An open, randomized, controlled study with two parallel treatment groups was done to evaluate the efficacy of a Lippia sidoides essential oil (EO) 1% mouthrinse compared with chlorhexidine 0.12% mouthrinse, applied two times daily for 1 week, in the treatment of dental plaque and gingivitis. Fifty‐five patients were included in the study. The efficacy variables were the colony count of Streptococcus mutans from the stimulated saliva and periodontal indices on days 0, 7 and 30 after commencement of therapy. Twenty eight patients received chlorhexidine mouthrinse (Periogard®) and 27 Lippia sidoides essential oil mouthrinse (Cepakill®). The clinical and microbiological parameters were significantly reduced by both mouthrinses. No significant difference was seen between the two groups (p > 0.05). There was a significant reduction in the colony count of S. mutans in both groups (p < 0.05). Chlorhexidine treatment reduced more efficiently than L. sidoides, however, no statistical difference was seen, the efficacy of both groups was similar (p = 0.3). The results indicate that Chlorhexidine mouthrinse reduced plaque index, gingival bleeding and the number of CFU (colonies forming units) more efficiently than L. sidoides but did not reach statistical significance. This study demonstrated that Lippia sidoides EO mouthrinse is effective in reducing microbial plaque and gingival inflammation. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
133.
134.
Lumbar spinal stenosis (LSS) functionally impacts significant numbers of Americans per year. Current estimates place the number of Americans suffering from senescent lumbar spinal stenosis at 400,000. The prevalence of this disorder in patients ranging from 60 to 69 years of age is very high. Forty‐seven percent of this age group have mild to moderate stenosis, and 19.7% have severe stenosis. As the baby boomer generation gets older, 10,000 individuals attain the age of 65 years every day in United States. LSS is becoming very common and will be a major healthcare issue as the population ages. Although LSS is not life threatening, it can cause substantial disability with limitations to performing daily activities, and thus, the associated negative impact on quality of life (QOL). This article reviews the pathophysiology and current treatment options for LSS, focusing on evidence‐based treatment options.  相似文献   
135.

Ethnopharmacological relevance

Petiveria alliacea L. (tipi) a shrub from Phytolaccaceae family is popularly used in folk medicine for treating a wide variety of disorders in South and Central America.

Aim of the study

To investigate the neuropharmacological properties on experimental animals.

Materials and methods

The acetate (FA), hexanic (FH), hydroalcoholic (FHA) and precipitated hydroalcoholic (FHAppt) fractions from the root of tipi were studied to investigate its pharmacological properties in the classical behavioral models (open-field, elevated plus maze-EPM, rotarod, barbiturate-induced sleeping time, forced swimming and pentylenetetrazole (PTZ)-induced convulsions tests) using mice. These fractions were administered intraperitoneally and orally to female mice at single doses of 100 and 200 mg/kg.

Results

All these fractions decreased the locomotor activity, rearing and grooming in the open-field test, suggesting a possible central depressant action. No significant effect was evident on motor coordination of the animals in the rotarod test. On EPM, all the fractions of tipi presented a significant reduction on the time of permanence in the open arms, indicating an absence of anxiolytic-like effect. In addition, the fractions increased the immobility time in the forced swimming test and potentiated pentobarbital-induced sleeping time in mice, confirmed a probable sedative and central depressant effect. Furthermore, the fractions increased the latency to the first convulsion and the lethal time of the PTZ-induced convulsions test in the animals, confirmed its popular use as anticonvulsant.

Conclusion

Our results suggest that the fractions of P. alliacea L. contains biologically active substance(s) that might be acting in the CNS and have significant depressant and anticonvulsant potentials, supporting folk medicine use of this plant.  相似文献   
136.
137.
<正>Drug delivery to the posterior segment of the eye,especially the retina,faces the unique challenges of various anatomical and physiological barriers.Invasive intravitreal injection is currently the mainstream clinical approach to posterior eye diseases such as age-related macular degeneration,diabetic retinopathy,uveitis,and cytomegalovirus retinitis.Repeated  相似文献   
138.
139.
Hirschsprung disease (HSCR) is a developmental disorder characterized by the absence of ganglion cells in the myenteric and submucosal plexuses due to a defect in the migration process of neural crest neuroblasts. Manifestation of the disease has been linked to the dysfunction of two principal signalling pathways involved in the enteric nervous system (ENS) formation: the RET-GDNF and the EDN3-EDNRB receptor systems. However, the NTF3/NTRK3 signalling pathway plays an essential role in the development of the ENS suggesting a potential role for those genes in the pathogenesis of HSCR. We have sought to evaluate the candidature of the NTRK3 gene, which encodes the TrkC receptor, as a susceptibility gene for Hirschsprung disease. Using dHPLC technology we have screened the NTRK3 coding region in 143 Spanish HSCR patients. A total of four previously described polymorphisms and 12 novel sequence variants were detected. Of note, the novel R645C mutation was detected in 2 affected siblings of a HSCR family also carrying a RET splicing mutation. Using bioinformatics tools we observed that the presence of an additional cysteine residue might implicate structural alterations in the mutated protein. We propose haploinsufficiency as the most probable mechanism for the NTRK3 R645C mutation. NTRK3 and RET mutations in this family only appear together in the HSCR patients, suggesting that they per se are necessary but not sufficient to produce the phenotype. In addition, it is quite probable that the contribution of other still unidentified modifier genes, may be responsible for the different phenotypes (length of aganglionosis) in the two affected members.  相似文献   
140.
Patients with sickle cell disease (SCD) have been shown to have impaired visual-motor speed and coordination. Sensorimotor deficits in mice can be investigated by motor coordination tests that require whole body movements such as the rotorod. A sickle transgenic mouse model (S+S-Antilles) that expresses human α, human β S and human β S-Antilles , is homozygous for the mouse β major deletion, and has low plasma arginine was compared to control C57BL/6J mice and S+S-Antilles mice supplemented with 5% arginine on the rotorod. The rotorod consists of a 2.5 cm diameter, grooved rod turning at constant acceleration, requiring postural adjustments on the part of the mice to maintain equilibrium. C57BL mice on Purina ® mouse chow had an average latency to fall of 169±61 s, S+S-Antilles mice on Purina ® mouse chow had an average of 127±56 s ( P <0.005 ). S+S-Antilles mice after 5% arginine supplementation had a mean latency of 180±32 s ( P <0.003 ). Arginine may improve rotorod performance in sickle transgenic mice by increasing NO synthesis thereby improving vasodilatation and blood flow with reversal of ischemia in brain and/or muscle. In conclusion, impaired rotorod performance in sickle transgenic mice presents an opportunity to apply this simple task to provide an efficient method to screen some types of therapeutic regimens for efficacy in SCD.  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