全文获取类型
收费全文 | 3255134篇 |
免费 | 239691篇 |
国内免费 | 5697篇 |
专业分类
耳鼻咽喉 | 44744篇 |
儿科学 | 106286篇 |
妇产科学 | 89751篇 |
基础医学 | 474013篇 |
口腔科学 | 90048篇 |
临床医学 | 296229篇 |
内科学 | 627827篇 |
皮肤病学 | 73001篇 |
神经病学 | 260238篇 |
特种医学 | 121749篇 |
外国民族医学 | 905篇 |
外科学 | 487869篇 |
综合类 | 72105篇 |
现状与发展 | 15篇 |
一般理论 | 1197篇 |
预防医学 | 257345篇 |
眼科学 | 75852篇 |
药学 | 238933篇 |
11篇 | |
中国医学 | 6859篇 |
肿瘤学 | 175545篇 |
出版年
2021年 | 25764篇 |
2019年 | 26605篇 |
2018年 | 36948篇 |
2017年 | 27809篇 |
2016年 | 31393篇 |
2015年 | 35253篇 |
2014年 | 50074篇 |
2013年 | 75165篇 |
2012年 | 102890篇 |
2011年 | 109875篇 |
2010年 | 65036篇 |
2009年 | 61594篇 |
2008年 | 102313篇 |
2007年 | 108814篇 |
2006年 | 110009篇 |
2005年 | 106774篇 |
2004年 | 102331篇 |
2003年 | 98151篇 |
2002年 | 94800篇 |
2001年 | 150398篇 |
2000年 | 154166篇 |
1999年 | 129280篇 |
1998年 | 37804篇 |
1997年 | 33458篇 |
1996年 | 33511篇 |
1995年 | 31657篇 |
1994年 | 29204篇 |
1993年 | 27432篇 |
1992年 | 99483篇 |
1991年 | 96594篇 |
1990年 | 93913篇 |
1989年 | 90466篇 |
1988年 | 83323篇 |
1987年 | 81340篇 |
1986年 | 76259篇 |
1985年 | 73197篇 |
1984年 | 54953篇 |
1983年 | 46706篇 |
1982年 | 28125篇 |
1979年 | 50115篇 |
1978年 | 35598篇 |
1977年 | 29654篇 |
1976年 | 28276篇 |
1975年 | 30013篇 |
1974年 | 36239篇 |
1973年 | 34545篇 |
1972年 | 32551篇 |
1971年 | 30486篇 |
1970年 | 28364篇 |
1969年 | 26819篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
101.
102.
Huda Mohammed Alkreathy Mayson H. Alkhatib Safaa Ahmed Al Musaddi Khadijah Saeed A. Balamash Nadia Nour Osman Aftab Ahmad 《Clinical and experimental pharmacology & physiology》2019,46(5):496-505
Doxorubicin (DOX) is the most commonly used anticancer drug; however, it has limited use because prolonged administration may result in severe cardiotoxicity. Simvastatin (SIM), generally prescribed for hypercholesterolaemia, has also shown salubrious results in the monotherapy or combinational drug therapy of different cancers in various models. Nanoparticle drug delivery systems are a novel way of improving therapeutics and also improving the absorption and specificity of drugs towards tumour cells. In this study, we exploited this technology to increase drug specificity and minimize imminent adverse effects. In this study, the antitumour activity of the combination formulas of DOX and SIM, either loaded in water (DOX‐SIM‐Solution) or nanoemulsions (NEs) (DOX‐SIM‐NE), was evaluated in a Swiss albino mouse model of Ehrlich ascites carcinoma. The anticancer effect was assessed by quantifying the change in body weight, mean survival time, and percent increase in lifespan (%ILS), determining haematological and serum biochemical parameters (liver function test, kidney function test and lipid profile parameters) as well as studying the histopathological alterations in liver tissues. We observed a clear increase in %ILS of the DOX‐SIM‐Solution group (265.30) that was double the %ILS of the DOX‐SIM‐NE group (134.70). However, DOX‐SIM‐NE had a non‐toxic effect on the haematological parameters, whereas DOX‐SIM‐Solution increased the levels of haemoglobin and lymphocytes. Furthermore, the encapsulation of SIM and DOX into NEs improved the levels of all serum biochemical parameters compared to the DOX‐SIM‐Solution. A reduction in the side effects of DOX‐SIM‐NE on the liver was also established using light microscopy, which revealed that the morphologies of the hepatocytes of the mice were less affected by administration of the DOX‐SIM‐NE treatment than with the DOX‐SIM‐Solution treatment. The study showed that incorporating SIM into the DOX‐loaded‐NE formulation remarkably improved its efficiency and simultaneously reduced its adverse effects. 相似文献
103.
Emma J. Walker Noni E. MacDonald Nehal Islam Nicole Le Saux Karina A. Top Deshayne B. Fell 《Vaccine》2019,37(13):1725-1735
Objective
To systematically review literature on uptake and timeliness of diphtheria-tetanus-pertussis, measles-mumps-rubella, and/or polio-containing vaccines in infants who were born preterm, with a low birth weight, and/or with chronic health conditions that were diagnosed within the first 6?months of life.Methods
Using a standardized search strategy developed by a medical librarian, records were extracted from MEDLINE, Embase, Database of Abstracts of Reviews of Effects, and CINAHL up to May 8, 2018.Results
Out of the 1997 records that were screened, we identified 21 studies that met inclusion criteria. Eleven studies assessed vaccine coverage and/or timeliness in preterm infants, 6 in low birth weight infants, and 7 in children with chronic health conditions. Estimates of coverage in these populations were highly variable, ranging from 40% to 100% across the vaccines and population groups.Conclusions
There is a lack of studies reporting coverage and timeliness of routine immunizations in special populations of children.Policy implications
Our review suggests a need for improved surveillance of immunization status in special populations of infants, as well as a need for standardization of reporting practices. 相似文献104.
Anastasiia Panfilova Sarah E. Shelton Cristina Caresio Ruud J.G. van Sloun Filippo Molinari Hessel Wijkstra Paul A. Dayton Massimo Mischi 《Ultrasound in medicine & biology》2019,45(2):539-548
Dynamic contrast-enhanced ultrasound (DCE-US) has been proposed as a powerful tool for cancer diagnosis by estimation of perfusion and dispersion parameters reflecting angiogenic vascular changes. This work was aimed at identifying which vascular features are reflected by the estimated perfusion and dispersion parameters through comparison with acoustic angiography (AA). AA is a high-resolution technique that allows quantification of vascular morphology. Three-dimensional AA and 2-D DCE-US bolus acquisitions were used to monitor the growth of fibrosarcoma tumors in nine rats. AA-derived vascular properties were analyzed along with DCE-US perfusion and dispersion to investigate the differences between tumor and control and their evolution in time. AA-derived microvascular density and DCE-US perfusion exhibited good agreement, confirmed by their spatial distributions. No vascular feature was correlated with dispersion. Yet, dispersion provided better cancer classification than perfusion. We therefore hypothesize that dispersion characterizes vessels that are smaller than those visible with AA. 相似文献
105.
106.
Leyi Wang Saraswathi Lanka Debbie Cassout Nohra E. Mateus‐Pinilla Ganwu Li William C. Wilson Dongwan Yoo Paul Shelton Richard L. Fredrickson 《Transboundary and Emerging Diseases》2019,66(5):1809-1820
First described in 1955 in New Jersey, epizootic haemorrhagic disease (EHD) causes a severe clinical disease in wild and domestic ruminants worldwide. Epizootic haemorrhagic disease outbreaks occur in deer populations each year from summer to late autumn. The etiological agent is EHD virus (EHDV) which is a double‐stranded segmented icosahedral RNA virus. EHD virus utilizes point mutations and reassortment strategies to maintain viral fitness during infection. In 2018, EHDV serotype 2 was predominantly detected in deer in Illinois. Whole genome sequencing was conducted for two 2018 EHDV2 isolates (IL41747 and IL42218) and the sequence analyses indicated that IL42218 was a reassortant between different serotypes whereas IL41747 was a genetically stable strain. Our data suggest that multiple strains contribute to outbreaks each year. 相似文献
107.
Sania Amr Magdy Garas Dina N. K. Boulos Doa’a A. Saleh Irene A. Jillson Christopher A. Loffredo 《Journal of substance use》2019,24(3):341-345
Background: Egyptian street youth use substances including tobacco, illicit drugs, and pharmaceutical drugs. To understand the circumstances, including adverse childhood experiences, that place adolescents at risk for engaging in substance use, we conducted in-depth interviews among a sample of Egyptian street children. Methods: From youth residing at or attending Caritas, a non-profit organization, which provides shelter and education to street youth, seven girls and twelve boys, aged 12–18 years, participated in open-ended, in-depth interviews. Results: Eight out of the 19 participants reported family history (early exposure) to substance use; and seven of them were initiated by either a family member (sibling), friend or coworker. Most of the participants reported a history of conflict with or abuse (verbal or physical) by their parents or siblings, or stressful situations at home; they used substance(s) to alleviate their stress. Few attended school, and some were forced to work and help their family. Conclusions: Among Egyptian youth, adverse childhood experiences, such as poverty, child abuse, and family substance use, challenge somewhat susceptible youths and lead them to the path of substance use and addiction. Prevention intervention should be multifaceted, culturally adaptable, and primarily targeting the social environment during childhood. 相似文献
108.
109.
110.
Alexander Real Chierika Ukogu Divya Krishnamoorthy Nicole Zubizarreta Samuel K. Cho Andrew C. Hecht James C. Iatridis 《The spine journal》2019,19(2):225-231