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   5445篇
  免费   527篇
  国内免费   118篇
耳鼻咽喉   17篇
儿科学   55篇
妇产科学   28篇
基础医学   585篇
口腔科学   185篇
临床医学   540篇
内科学   422篇
皮肤病学   20篇
神经病学   453篇
特种医学   209篇
外国民族医学   4篇
外科学   442篇
综合类   1036篇
现状与发展   3篇
预防医学   724篇
眼科学   200篇
药学   730篇
  2篇
中国医学   231篇
肿瘤学   204篇
  2024年   10篇
  2023年   57篇
  2022年   124篇
  2021年   189篇
  2020年   187篇
  2019年   135篇
  2018年   128篇
  2017年   115篇
  2016年   156篇
  2015年   161篇
  2014年   471篇
  2013年   437篇
  2012年   541篇
  2011年   546篇
  2010年   332篇
  2009年   359篇
  2008年   261篇
  2007年   319篇
  2006年   323篇
  2005年   200篇
  2004年   195篇
  2003年   131篇
  2002年   96篇
  2001年   110篇
  2000年   85篇
  1999年   71篇
  1998年   75篇
  1997年   73篇
  1996年   69篇
  1995年   43篇
  1994年   27篇
  1993年   18篇
  1992年   12篇
  1991年   5篇
  1990年   9篇
  1989年   4篇
  1988年   16篇
排序方式: 共有6090条查询结果,搜索用时 15 毫秒
91.
《Sport》2013,29(3):229-236
BackgroundAlways carefully watching the climber, the belayer has to keep a position for a long time, which is damaging to the cervical spine. This often causes stiffness in the neck, which leads to cervical restrictions of motion. 3 types of belaying, the habitual belaying, the “CU glasses” and the “coordinated head position”, have been examined relating to their ability to avoid muscular tensions.Materials and methodsThe mobility of the cervical spine of 30 male and female climbers has been measured with an inclinometer immediately before and after defined belaying of 10 min. The subjects have been distributed to the 3 types of belaying at random. Additional the subjects had to answer questions concerning their personal feelings and a pain-rating-scale.ResultsWithin the group with habitual belaying, significant limitations in the mobility of the cervical spine in each direction could be determined, connected with strong pain after defined belaying. While using the “CU glasses” or “coordinated head posture”, no restrictions in movement (for each direction p>.05) has been noticed. Subjects that belayed with the “coordinated head posture” complained about backache because of the unfamiliar, active posture.ConclusionsDepending on the actual climbing-situation, the belayer should use either the „CU glasses“ or the „coordinated head posture“, in order to avoid muscular tension in the neck.Level of evidenceIIa  相似文献   
92.
Contributors     
《Cardiology Clinics》2016,34(4):iii-v
  相似文献   
93.
Brucellosis is an important zoonotic disease caused by Brucella spp. We present a phylogeny of 552 strains based on genome-wide single nucleotide polymorphisms (SNPs) determined by an alignment-free k-mer approach. A total of 138,029 SNPs were identified from 552 Brucella genomes. Of these, 31,152 and 106,877 were core and non-core SNPs, respectively. Based on pan-genome analysis 11,937 and 972 genes were identified as pan and core genome, respectively. The pan-genome-wide analysis studies (Pan-GWAS) could not identify the group-specific variants in Brucella spp. Therefore, we focused on SNP based genome-wide association studies (SNP-GWAS) to identify the species-specific genetic determinants in Brucella spp. Phylogenetic tree representing eleven recognized Brucella spp. showed 16 major lineages. We identified 143 species-specific SNPs in Brucella abortus that are conserved in 311 B. abortus genomes. Of these, 141 species-specific SNPs were confined in the positively significant SNPs of B. abortus using SNP-GWAS. Since conserved in all the B. abortus genomes studied, these SNPs might have originated very early during the evolution of B. abortus and might be responsible for the evolution of B. abortus with cattle as the preferred host. Similarly, we identified 383 species-specific SNPs conserved in 132 Brucella melitensis genomes. Of these 379 species-specific SNPs were identified as positively associated using GWAS. Interestingly, > 98% of the SNPs that are significantly, positively associated with the traits showed 100% sensitivity and 100% specificity. These identified species-specific core-SNPs identified in Brucella genomes could be responsible for the speciation and their respective host adaptation.  相似文献   
94.
《Research in microbiology》2018,169(9):515-521
Bacterial biofilms, highly resistant to the conventional antimicrobial therapy, remain an unresolved challenge pressing the medical community to investigate new and alternative strategies to fight chronic implant-associated infections. Recently, strictly lytic bacteriophages have been revalued as powerful agents to kill antibiotic-resistant bacteria even in biofilm. Here, the interaction of T3 bacteriophage and planktonic and biofilm Escherichia coli TG1, respectively, was evaluated using isothermal microcalorimetry. Microcalorimetry is a non-invasive and highly sensitive technique measuring growth-related heat production of microorganisms in real-time. Planktonic and biofilm E. coli TG1 were exposed to different titers of T3 bacteriophage, ranging from 102 to 107 PFU/ml. The incubation of T3 with E. coli TG1 showed a strong inhibition of heat production both in planktonic and biofilm already at lower bacteriophage titers (103 PFU/ml). This method could be used to screen and evaluate the antimicrobial potential of different bacteriophages, alone and in combination with antibiotics in order to improve the treatment success of biofilm-associated infections.  相似文献   
95.
Dietary supplementation exerts beneficial effects in reducing incidence of chronic neurodegenerative diseases. The purpose of this study was to examine protective effects of mussel (Mytilus edulis) oligopeptides supplementation on brain function in d-galactose induced aging mice. Sixty female 8-month-old mice were randomly divided into five groups: vehicle control, d-galactose, and d-galactose combined with 200, 500, 1000 mg/kg mussel oligopeptides. The results showed that mussel oligopeptides could improve cognitive learning and memory ability and protect the hippocampal neurons. In addition, GSH, SOD and GSH-pX activities were increased and MDA level was significantly decreased in mice fed with mussel oligopeptides. It was also found that mussel oligopeptides supplementation prevented d-galactose-induced elevations of iNOS activity and NO production and lactate acid levels in brain. Moreover, PI3K and Akt genes were up-regulated by mussel oligopeptides supplementation. These findings suggest that mussel oligopeptides are able to enhance exercise capacity and protect against oxidative damage caused by d-galactose in aging model mice through regulating oxidation metabolism and PI3K/Akt/NOS signal pathway. Therefore, mussel oligopeptides are good materials for future development of healthcare products to combat age-related brain dysfunction and to improve healthy life span.  相似文献   
96.
目的探讨大剂量甲氨蝶呤(MTX)治疗急性淋巴细胞白血病的有效解救方法。方法选取我院收治的急性淋巴细胞白血病患者45例,随机分成观察组(23例)和对照组(22例)。45例患者均应用大剂量MTX进行治疗,观察组患者监测血药浓度并随时调整解救药的剂量,对照组患者应用固定剂量的解救药进行解救。比较两组患者不良反应的发生情况。结果观察组皮肤黏膜损害、胃肠道反应、肝功能损害、肾功能损害、骨髓抑制的发生率均低于对照组,且两组胃肠道反应、肝功能损害、骨髓抑制发生率的差异具有统计学意义(P<0.05)。结论在应用大剂量MTX进行治疗的过程中进行血药浓度的密切监测并及时调整解救药浓度能够达到更好的治疗效果。  相似文献   
97.
98.
99.
100.
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