全文获取类型
收费全文 | 960121篇 |
免费 | 65231篇 |
国内免费 | 1674篇 |
专业分类
耳鼻咽喉 | 13008篇 |
儿科学 | 32233篇 |
妇产科学 | 26849篇 |
基础医学 | 147779篇 |
口腔科学 | 26648篇 |
临床医学 | 84273篇 |
内科学 | 182340篇 |
皮肤病学 | 21673篇 |
神经病学 | 68120篇 |
特种医学 | 35945篇 |
外国民族医学 | 116篇 |
外科学 | 145215篇 |
综合类 | 21727篇 |
现状与发展 | 3篇 |
一般理论 | 299篇 |
预防医学 | 68846篇 |
眼科学 | 22517篇 |
药学 | 71655篇 |
3篇 | |
中国医学 | 3037篇 |
肿瘤学 | 54740篇 |
出版年
2018年 | 10847篇 |
2017年 | 8319篇 |
2016年 | 9386篇 |
2015年 | 10510篇 |
2014年 | 14165篇 |
2013年 | 21631篇 |
2012年 | 28202篇 |
2011年 | 29462篇 |
2010年 | 17950篇 |
2009年 | 16760篇 |
2008年 | 27451篇 |
2007年 | 29603篇 |
2006年 | 29862篇 |
2005年 | 28074篇 |
2004年 | 27319篇 |
2003年 | 25906篇 |
2002年 | 25046篇 |
2001年 | 47428篇 |
2000年 | 48310篇 |
1999年 | 40004篇 |
1998年 | 10462篇 |
1997年 | 9120篇 |
1996年 | 9254篇 |
1995年 | 8819篇 |
1994年 | 8155篇 |
1993年 | 7506篇 |
1992年 | 30091篇 |
1991年 | 30079篇 |
1990年 | 29305篇 |
1989年 | 28863篇 |
1988年 | 26300篇 |
1987年 | 25443篇 |
1986年 | 24175篇 |
1985年 | 22956篇 |
1984年 | 16796篇 |
1983年 | 14322篇 |
1982年 | 8101篇 |
1979年 | 15448篇 |
1978年 | 10977篇 |
1977年 | 9235篇 |
1976年 | 8796篇 |
1975年 | 9751篇 |
1974年 | 11495篇 |
1973年 | 11159篇 |
1972年 | 10461篇 |
1971年 | 9748篇 |
1970年 | 9427篇 |
1969年 | 8627篇 |
1968年 | 8091篇 |
1967年 | 7341篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
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
72.
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
73.
74.
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
75.
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
76.
77.
O. Morris M. Fairclough J. Grigg C. Prenant A. McMahon 《Journal of labelled compounds & radiopharmaceuticals》2019,62(1):4-23
Affinity peptide and protein‐ (APP) based radiotracers are an increasingly popular class of radiotracer in positron emission tomography (PET), which was once dominated by the use of small molecule radiotracers. Radiolabelled monoclonal antibodies (mAbs) are important examples of APPs, yet a preference for smaller APPs, which exhibit fast pharmacokinetics and permit rapid PET aided diagnosis, has become apparent. 18F exhibits favourable physical characteristics for APP radiolabelling and has been described as an ideal PET radionuclide. Notwithstanding, 18F radiolabelling of APP is challenging, and this is echoed in the literature where a number of diverse approaches have been adopted. This review seeks to assess and compare the approaches taken to 18F APP radiolabelling with the intention of highlighting trends within this expanding field. Generic themes have emerged in the literature, namely the use of mild radiolabelling conditions, a preference of site‐specific methodologies with an impetus for short, automated procedures which produce high‐yielding [18F]APPs. 相似文献
78.
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
Purpose
A hydrogel rectal spacer (HRS) is a medical device that is approved by the U.S. Food and Drug Administration to increase the separation between the prostate and rectum. We conducted a cost-effectiveness analysis of HRS use for reduction in radiation therapy (RT) toxicities in patients with prostate cancer (PC) undergoing external beam RT (EBRT).Methods and Materials
A multistate Markov model was constructed from the U.S. payer perspective to examine the cost-effectiveness of HRS in men with localized PC receiving EBRT (EBRT alone vs EBRT + HRS). The subgroups analyzed included site of HRS placement (hospital outpatient, physician office, ambulatory surgery center) and proportion of patients with good baseline erectile function (EF). Data on EF, gastrointestinal and genitourinary toxicities incidence, and potential risks associated with HRS implantation were obtained from a recently published randomized clinical trial. Health utilities and costs were derived from the literature and the 2018 Physician Fee Schedule and were discounted 3% annually. Quality-adjusted life years (QALYs) and costs were modeled for a 5-year period from receipt of RT. Probabilistic sensitivity analysis and value-based threshold analyses were conducted.Results
The per-patient 5-year incremental cost for spacers administered in a hospital outpatient setting was $3578, and the incremental effectiveness was 0.0371 QALYs. The incremental cost-effectiveness ratio was $96,440/QALY for patients with PC undergoing HRS insertion in a hospital and $39,286/QALY for patients undergoing HRS insertion in an ambulatory facility. For men with good baseline EF, the incremental cost-effectiveness ratio was $35,548/QALY and $9627/QALY in hospital outpatient and ambulatory facility settings, respectively.Conclusions
Based on the current Medicare Physician Fee Schedule, HRS is cost-effective at a willingness to pay threshold of $100,000. These results contain substantial uncertainty, suggesting more evidence is needed to refine future decision-making. 相似文献79.
80.
Erik de Bakker Mirthe A. M. van der Putten Martijn W. Heymans Sander W. Spiekstra Taco Waaijman Liselotte Butzelaar Vera L. Negenborn Vivian K. Beekman Erman O. Akpinar Thomas Rustemeyer Frank B. Niessen Susan Gibbs 《Experimental dermatology》2021,30(1):169-178
Unpredictable hypertrophic scarring (HS) occurs after approximately 35% of all surgical procedures and causes significant physical and psychological complaints. Parallel to the need to understanding the mechanisms underlying HS formation, a prognostic tool is needed. The objective was to determine whether (systemic) immunological differences exist between patients who develop HS and those who develop normotrophic scars (NS) and to assess whether those differences can be used to identify patients prone to developing HS. A prospective cohort study with NS and HS groups in which (a) cytokine release by peripheral blood mononuclear cells (PBMC) and (b) the irritation threshold (IT) after an irritant (sodium lauryl sulphate) patch test was evaluated. Univariate regression analysis of PBMC cytokine secretion showed that low MCP‐1, IL‐8, IL‐18 and IL‐23 levels have a strong correlation with HS (P < .010‐0.004; AUC = 0.790‐0.883). Notably, combinations of two or three cytokines (TNF‐a, MCP‐1 and IL‐23; AUC: 0.942, Nagelkerke R2: 0.727) showed an improved AUC indicating a better correlation with HS than single cytokine analysis. These combination models produce good prognostic results over a broad probability range (sensitivity: 93.8%, specificity 86.7%, accuracy 90,25% between probability 0.3 and 0.7). Furthermore, the HS group had a lower IT than the NS group and an accuracy of 68%. In conclusion, very fundamental immunological differences exist between individuals who develop HS and those who do not, whereas the cytokine assay forms the basis of a predictive prognostic test for HS formation, the less invasive, easily performed irritant skin patch test is more accessible for daily practice. 相似文献