全文获取类型
收费全文 | 3378篇 |
免费 | 203篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 47篇 |
儿科学 | 218篇 |
妇产科学 | 71篇 |
基础医学 | 461篇 |
口腔科学 | 30篇 |
临床医学 | 247篇 |
内科学 | 640篇 |
皮肤病学 | 93篇 |
神经病学 | 133篇 |
特种医学 | 239篇 |
外科学 | 342篇 |
综合类 | 202篇 |
预防医学 | 295篇 |
眼科学 | 54篇 |
药学 | 276篇 |
中国医学 | 49篇 |
肿瘤学 | 204篇 |
出版年
2023年 | 22篇 |
2022年 | 52篇 |
2021年 | 106篇 |
2020年 | 55篇 |
2019年 | 49篇 |
2018年 | 81篇 |
2017年 | 52篇 |
2016年 | 68篇 |
2015年 | 91篇 |
2014年 | 119篇 |
2013年 | 146篇 |
2012年 | 194篇 |
2011年 | 217篇 |
2010年 | 146篇 |
2009年 | 102篇 |
2008年 | 167篇 |
2007年 | 179篇 |
2006年 | 169篇 |
2005年 | 142篇 |
2004年 | 103篇 |
2003年 | 104篇 |
2002年 | 91篇 |
2001年 | 96篇 |
2000年 | 92篇 |
1999年 | 67篇 |
1998年 | 57篇 |
1997年 | 45篇 |
1996年 | 44篇 |
1995年 | 34篇 |
1994年 | 22篇 |
1993年 | 32篇 |
1992年 | 43篇 |
1991年 | 46篇 |
1990年 | 51篇 |
1989年 | 56篇 |
1988年 | 49篇 |
1987年 | 34篇 |
1986年 | 36篇 |
1985年 | 42篇 |
1984年 | 19篇 |
1983年 | 19篇 |
1982年 | 18篇 |
1979年 | 24篇 |
1978年 | 24篇 |
1977年 | 20篇 |
1975年 | 16篇 |
1973年 | 21篇 |
1971年 | 17篇 |
1970年 | 16篇 |
1969年 | 16篇 |
排序方式: 共有3601条查询结果,搜索用时 15 毫秒
81.
Fragmented QRS on a 12-lead ECG: a predictor of mortality and cardiac events in patients with coronary artery disease. 总被引:3,自引:0,他引:3
Mithilesh Kumar Das Chandan Saha Hicham El Masry Jonathan Peng Gopi Dandamudi Jo Mahenthiran Paul McHenry Douglas P Zipes 《Heart rhythm》2007,4(11):1385-1392
BACKGROUND: Fragmented QRS (fQRS) on a 12-lead electrocardiogram (ECG) is associated with myocardial scar in patients with coronary artery disease (CAD). OBJECTIVE: We postulated that fQRS is a predictor of cardiac events and mortality in patients who have known CAD or who are being evaluated for CAD. METHODS: The cardiac events (myocardial infarction, need for revascularization, or cardiac death) and all-cause mortality were retrospectively reviewed in 998 patients (mean age 65.5 +/- 11.9 years, male 967) who underwent nuclear stress test. The fQRS on a 12-lead ECG included various RSR' patterns (> or =1 R' prime or notching of S wave or R wave) without typical bundle branch block in 2 contiguous leads corresponding to a major coronary artery territory. RESULTS: All-cause mortality (93 [34.1%] vs 188 [25.9%]) and cardiac event rate (135 [49.5%] vs 200 [27.6%]) were higher in the fQRS group compared with the non-fQRS group during a mean follow-up of 57 +/- 23 months. A Kaplan-Meier survival analysis revealed significantly lower event-free survival for cardiac events (P <.001) and all-cause mortality (P = .02). Multivariate Cox regression analysis revealed that significant fQRS was an independent significant predictor for cardiac events but not for all-cause mortality. The Kaplan-Meier survival analysis showed no significant difference between fQRS and Q waves groups for cardiac events (P = .48) and all-cause mortality (P = .08). CONCLUSION: The fQRS is an independent predictor of cardiac events in patients with CAD. It is associated with significantly lower event-free survival for a cardiac event on long-term follow-up. 相似文献
82.
83.
Kusal K. Das Jameel G. Jargar Sikha Saha Saeed M. Yendigeri Shashi Bala Singh 《Indian journal of pharmacology》2015,47(3):285-291
Objective:Lead (Pb) is a long-known poison of environment and industrial origin. Its prolonged exposure affects cellular material and alters cellular genetics and produces oxidative damages. In this study, we investigated the exposure of chronic sustained hypoxia or lead acetate alone or in combination with or without supplementation of α-tocopherol on hepatic oxidative and nitrosative stress in rats.Results:Exposure of both lead and hypoxia showed decreased body weight, altered serum lipid profile, oxidant and enzymatic antioxidants status, serum HIF-1α and VEGF concentrations. Simultaneous α-tocopherol supplementation showed beneficial effects to all these alterations. Histopathological observations also showed hepatic degenerative changes after lead or hypoxia exposure either alone or in combination, but remarkable improvement has been noticed after α-tocopherol supplementation.Conclusion:Supplementation of α-tocopherol is beneficial to counter both lead acetate and hypoxia induced hepatic cytotoxicities possibly by reducing oxidative and nitrosative stress.KEY WORDS: α-tocopherol, hypoxia, lead acetate, nitrosative stress, oxidative stress 相似文献
84.
Brianna Lindsay Joe Oundo M. Anowar Hossain Martin Antonio Boubou Tamboura Alan W. Walker Joseph N. Paulson Julian Parkhill Richard Omore Abu S.G. Faruque Suman Kumar Das Usman N. Ikumapayi Mitchell Adeyemi Doh Sanogo Debasish Saha Samba Sow Tamer H. Farag Dilruba Nasrin Shan Li Sandra Panchalingam Myron M. Levine Karen Kotloff Laurence S. Magder Laura Hungerford Halvor Sommerfelt Mihai Pop James P. Nataro O. Colin Stine 《Emerging infectious diseases》2015,21(2):242-250
Pathogens in the gastrointestinal tract exist within a vast population of microbes. We examined associations between pathogens and composition of gut microbiota as they relate to Shigella spp./enteroinvasive Escherichia coli infection. We analyzed 3,035 stool specimens (1,735 nondiarrheal and 1,300 moderate-to-severe diarrheal) from the Global Enteric Multicenter Study for 9 enteropathogens. Diarrheal specimens had a higher number of enteropathogens (diarrheal mean 1.4, nondiarrheal mean 0.95; p<0.0001). Rotavirus showed a negative association with Shigella spp. in cases of diarrhea (odds ratio 0.31, 95% CI 0.17–0.55) and had a large combined effect on moderate-to-severe diarrhea (odds ratio 29, 95% CI 3.8–220). In 4 Lactobacillus taxa identified by 16S rRNA gene sequencing, the association between pathogen and disease was decreased, which is consistent with the possibility that Lactobacillus spp. are protective against Shigella spp.–induced diarrhea. Bacterial diversity of gut microbiota was associated with diarrhea status, not high levels of the Shigella spp. ipaH gene. 相似文献
85.
Meenakshi Singh Abhijit Hazra Yogesh P. Bharitkar Ritu Kalia Ashutosh Sahoo Sneha Saha V. Ravichandiran Shekhar Ghosh Nirup B. Mondal 《RSC advances》2018,8(34):18938
Curcumin has been transformed to several diversely substituted bis-pyrrolizidino/thiopyrrolizidino oxindolo/acenaphthyleno curcuminoids via a sequential azomethine ylide cycloaddition reaction using isatins/acenaphthoquinone and proline/thioproline as the reagents. The products were separated via extensive chromatography and characterized by 1D/2D NMR and HRMS analysis.Curcumin has been transformed to several diversely substituted bis-pyrrolizidino/thiopyrrolizidino oxindolo/acenaphthyleno curcuminoids via a sequential azomethine ylide cycloaddition reaction. 相似文献
86.
S K Agarwal A Somani P S Gupta K Saha D D Kulpati U K Baveja 《The Journal of communicable diseases》1992,24(1):49-54
Secretory immunoglobulin A (S-IgA), coproantibody titre (antiamoebic) and IgA, IgG, IgM immunocytes in rectal mucosa were studied in 13 patients with amoebic liver abscess (ALA) prior to and 4-6 weeks after completion of antiamoebic therapy. Ten asymptomatic Entamoeba histolytica cyst passers and 17 healthy age and sex matched volunteers served as controls. Fecal S-IgA levels and counts of IgA bearing immunocytes in mucosa were significantly higher in patients with ALA and cyst passers as compared to healthy controls and showed a significant fall after treatment. Fecal antiamoebic antibodies were high in cyst passers and in cases of ALA after treatment. Raised levels of S-IgA and IgA class immunocyte counts probably indicate a local mucosal immune response directed at containing the infection. 相似文献
87.
88.
Exercise testing remains a key tool in the management of patientswith ischaemic heart disease (IHD) both in a diagnostic andrehabilitation setting. A familiar scenario involves performingan exercise test to identify inducible ischaemia either to determinewhether IHD is a likely diagnosis or as a prelude to a structuredexercise programme in individuals with a recent acute coronarysyndrome or with chronic symptoms in whom IHD has already beendiagnosed. Consequently, the prospect of prescribing exerciseto patients is a problem faced regularly by clinicians. However,there is still an appropriate level of concern in recommendingan activity which increases myocardial work and may provokean imbalance between myocardial oxygen supply and demand. Thisis despite the risk of exercise 相似文献
89.
Dextrocardia is a rare clinical phenomenon with a reported incidence of one in 10 000. Consequently, acute coronary syndromes in such patients are rare. When chest pain occurs in this setting, it is important to be aware of the unique problems that may occur if coronary intervention is contemplated. Previous case reports have shown successful attempts at reperfusing one coronary artery percutaneously. In this case, coronary stents were successfully deployed in two vessels of a man with situs inversus, which has not been reported before. Additionally, the angiographic results that followed from successful intervention did not produce the expected haemodynamic and electrocardiographic changes. 相似文献
90.
Saha Soma Pal Dey Poushali Mitra Souvik 《Proceedings of the National Academy of Sciences, India. Section B.》2021,91(4):919-927
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Microbial association is considered as a significant innovation for land colonization of mosses. Plagiomnium... 相似文献