全文获取类型
收费全文 | 725527篇 |
免费 | 51662篇 |
国内免费 | 1372篇 |
专业分类
耳鼻咽喉 | 9457篇 |
儿科学 | 23910篇 |
妇产科学 | 18039篇 |
基础医学 | 113310篇 |
口腔科学 | 20412篇 |
临床医学 | 65661篇 |
内科学 | 139062篇 |
皮肤病学 | 16404篇 |
神经病学 | 51429篇 |
特种医学 | 26381篇 |
外国民族医学 | 76篇 |
外科学 | 107832篇 |
综合类 | 15141篇 |
现状与发展 | 2篇 |
一般理论 | 173篇 |
预防医学 | 52988篇 |
眼科学 | 16839篇 |
药学 | 55109篇 |
3篇 | |
中国医学 | 2390篇 |
肿瘤学 | 43943篇 |
出版年
2021年 | 6177篇 |
2019年 | 6010篇 |
2018年 | 8563篇 |
2017年 | 6560篇 |
2016年 | 7292篇 |
2015年 | 8140篇 |
2014年 | 11010篇 |
2013年 | 16394篇 |
2012年 | 21972篇 |
2011年 | 22976篇 |
2010年 | 13529篇 |
2009年 | 12619篇 |
2008年 | 21233篇 |
2007年 | 22740篇 |
2006年 | 23123篇 |
2005年 | 21582篇 |
2004年 | 21051篇 |
2003年 | 19902篇 |
2002年 | 19392篇 |
2001年 | 36518篇 |
2000年 | 37063篇 |
1999年 | 30577篇 |
1998年 | 8072篇 |
1997年 | 6833篇 |
1996年 | 7111篇 |
1995年 | 6753篇 |
1994年 | 6218篇 |
1992年 | 23099篇 |
1991年 | 23061篇 |
1990年 | 22449篇 |
1989年 | 22199篇 |
1988年 | 20166篇 |
1987年 | 19549篇 |
1986年 | 18568篇 |
1985年 | 17421篇 |
1984年 | 12801篇 |
1983年 | 10849篇 |
1982年 | 6053篇 |
1979年 | 11596篇 |
1978年 | 8217篇 |
1977年 | 6907篇 |
1976年 | 6678篇 |
1975年 | 7334篇 |
1974年 | 8573篇 |
1973年 | 8201篇 |
1972年 | 7712篇 |
1971年 | 7161篇 |
1970年 | 6915篇 |
1969年 | 6355篇 |
1968年 | 5823篇 |
排序方式: 共有10000条查询结果,搜索用时 429 毫秒
61.
Lorena Martin-Morales Sara Manzano Maria Rodrigo-Faus Adrian Vicente-Barrueco Victor Lorca Gonzalo Núñez-Moreno Paloma Bragado Almudena Porras Trinidad Caldes Pilar Garre Alvaro Gutierrez-Uzquiza 《International journal of cancer. Journal international du cancer》2023,152(2):283-297
Matrix metalloproteinase-11 (MMP11) is an enzyme with proteolytic activity against matrix and nonmatrix proteins. Although most MMPs are secreted as inactive proenzymes and are later activated extracellularly, MMP11 is activated intracellularly by furin within the constitutive secretory pathway. It is a key factor in physiological tissue remodeling and its alteration may play an important role in the progression of epithelial malignancies and other diseases. TCGA colon and colorectal adenocarcinoma data showed that upregulation of MMP11 expression correlates with tumorigenesis and malignancy. Here, we provide evidence that a germline variant in the MMP11 gene (NM_005940: c.232C>T; p.(Pro78Ser)), identified by whole exome sequencing, can increase the tumorigenic properties of colorectal cancer (CRC) cells. P78S is located in the prodomain region, which is responsible for blocking MMP11's protease activity. This variant was detected in the proband and all the cancer-affected family members analyzed, while it was not detected in healthy relatives. In silico analyses predict that P78S could have an impact on the activation of the enzyme. Furthermore, our in vitro analyses show that the expression of P78S in HCT116 cells increases tumor cell invasion and proliferation. In summary, our results show that this variant could modify the structure of the MMP11 prodomain, producing a premature or uncontrolled activation of the enzyme that may contribute to an early CRC onset in these patients. The study of this gene in other CRC cases will provide further information about its role in CRC development, which might improve patient treatment in the future. 相似文献
62.
Chumakov E. M. Petrova N. N. Limankin O. V. Ashenbrenner Yu. V. 《Neuroscience and behavioral physiology》2022,52(1):45-51
Neuroscience and Behavioral Physiology - Objective. To determine the frequency, structure, and severity of cognitive impairments in patients with bipolar affective disorder (BAD) in remission.... 相似文献
63.
64.
Accurate diagnosis and recognition of predisposing factors has been shown to be challenging in lower limb cellulitis (LLC). Assessment of 1746 consecutive patients with cellulitis presenting to a UK university hospital showed increasing overdiagnosis, with only 31.9% of patients referred during the period 2015–2018 having the diagnosis of LLC confirmed. Recognition of at least one predisposing factor increased from 61% to 89% following introduction of more specific screening questions. This identified a need for better primary care dermatology education and the benefit of a proforma with specific screening questions for reversible predisposing factors for LLC. 相似文献
65.
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
66.
67.
68.
In both adults and children with diabetes, technologies such as continuous subcutaneous insulin infusion using insulin pumps and continuous glucose monitoring can help improve diabetes control, reduce hypoglycaemia and improve quality of life. Access to these technologies in the UK is very variable. Some technologies are recommended by the National Institute for Health and Care Excellence, while others have not been appraised, and new technologies are emerging all the time. Additionally, different guidelines for adults and children further complicate access to diabetes technology in the transition from paediatric to adult care. Against this background, Diabetes UK and NHS England have brought together a multidisciplinary group of experts, including clinicians and people with diabetes, to develop this consensus guideline, combining the different technologies into a common pathway to aid clinical and policy decision‐making. We created a pathway that supports the incremental addition of technology as monotherapy and then dual therapy in the same way that we incrementally add in therapeutic agents to support people with Type 2 diabetes to achieve their personalized glycaemic targets. The pathway emphasizes the importance of structured education, specialist support and appropriate access to psychological therapies, as essential pillars for optimized use of diabetes‐related technology, and recommends the re‐evaluation of its use when the individual is unable either to use the technology appropriately or to achieve the intended outcomes. This pathway is endorsed by UK‐wide clinical and patient associations and we recommend that providers and commissioners use it to ensure the right individual with diabetes has access to the right technology in a timely way to help achieve better outcomes. 相似文献
69.
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
Background Context
Low back pain (LBP) is a common complaint in clinical practice of multifactorial origin. Although obesity has been thought to contribute to LBP primarily by altering the distribution of mechanical loads on the spine, the additional contribution of obesity-related conditions such as diabetes mellitus (DM) to LBP has not been thoroughly examined.Purpose
To determine if there is a relationship between DM and LBP that is independent of body mass index (BMI) in a large cohort of adult survey participants.Study Design
Retrospective analysis of prospectively collected National Health and Nutrition Examination Survey (NHANES) data to characterize associations between LBP, DM, and BMI in adults subdivided into 6 subpopulations: normal weight (BMI 18.5–25), overweight (BMI 25–30), and obese (BMI >30) diabetics and nondiabetics. Diabetes was defined with glycohemoglobin A1c (HbA1c) ≥6.5%.Patient Sample
11,756 participants from NHANES cohort.Outcome Measures
Percentage of LBP reported.Methods
LBP reported in the 1999-2004 miscellaneous pain NHANES questionnaire was the dependent variable examined. Covariates included HbA1c, BMI, age, and family income ratio to poverty as continuous variables as well as race, gender, and smoking as binary variables. Individuals were further subdivided by weight class and diabetes status. Regression and graphical analyses were performed on the study population as a whole and also on subpopulations.Results
Increasing HbA1c did not increase the odds of reporting LBP in the full cohort. However, multivariate logistic regression of the 6 subpopulations revealed that the odds of LBP significantly increased with increasing HbA1c levels in normal weight diabetics. No other subpopulations reported significant relationships between LBP and HbA1c. LBP was also significantly associated with BMI for normal weight diabetics and also for obese subjects regardless of their DM status.Conclusions
LBP is significantly related to DM status, but this relationship is complex and may interact with BMI. These results support the concept that LBP may be improved in normal weight diabetic subjects with improved glycemic control and weight loss, and that all obese LBP subjects may benefit from improved weight loss alone. 相似文献70.
Joseph F. Levy Rahul Khairnar Alexander V. Louie Timothy N. Showalter C. Daniel Mullins Mark V. Mishra 《Practical radiation oncology》2019,9(2):e172-e179