全文获取类型
收费全文 | 1216篇 |
免费 | 79篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 110篇 |
妇产科学 | 15篇 |
基础医学 | 158篇 |
口腔科学 | 27篇 |
临床医学 | 76篇 |
内科学 | 222篇 |
皮肤病学 | 12篇 |
神经病学 | 146篇 |
特种医学 | 9篇 |
外科学 | 246篇 |
综合类 | 23篇 |
一般理论 | 1篇 |
预防医学 | 63篇 |
眼科学 | 12篇 |
药学 | 100篇 |
中国医学 | 7篇 |
肿瘤学 | 63篇 |
出版年
2023年 | 10篇 |
2022年 | 13篇 |
2021年 | 26篇 |
2020年 | 13篇 |
2019年 | 29篇 |
2018年 | 37篇 |
2017年 | 25篇 |
2016年 | 32篇 |
2015年 | 50篇 |
2014年 | 44篇 |
2013年 | 74篇 |
2012年 | 86篇 |
2011年 | 102篇 |
2010年 | 57篇 |
2009年 | 51篇 |
2008年 | 79篇 |
2007年 | 85篇 |
2006年 | 95篇 |
2005年 | 69篇 |
2004年 | 50篇 |
2003年 | 51篇 |
2002年 | 57篇 |
2001年 | 25篇 |
2000年 | 12篇 |
1999年 | 21篇 |
1998年 | 11篇 |
1997年 | 9篇 |
1996年 | 13篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1919年 | 1篇 |
排序方式: 共有1300条查询结果,搜索用时 15 毫秒
91.
Effects of Nd:YAG laser photoradiation on intra-abdominal tissues: a histological study of tissue damage versus power density applied 总被引:1,自引:0,他引:1
Liver, spleen, and pancreas were subjected to laser photoradiation of 50- to 100-Watt power levels. Samples were evaluated by light microscopy at 0 hours and 7, 14, and 21 days. Four zones of cellular damage were visible in liver and pancreas: coagulum, cavitation, acidophilia, and transition. Only the first three zones were clearly visible in the spleen. Mean lateral tissue penetration was 3.1 mm in liver, 3.3 mm in spleen, and 1.0 mm in pancreas. No significant increase in lateral penetration occurred with increasing power. Normal healing was observed in liver and spleen. Pancreatitis was found in all samples at 7 days postoperatively. At power levels of 80 W or less, recovery was observed. Above 80 W, pancreatic pseudocysts and necrosis led to death of the animals. 相似文献
92.
Ivan P Gorlov Kanishka Sircar Hongya Zhao Sankar N Maity Nora M Navone Olga Y Gorlova Patricia Troncoso Curtis A Pettaway Jin Young Byun Christopher J Logothetis 《BMC cancer》2010,10(1):599
Background
The genetic control of prostate cancer development is poorly understood. Large numbers of gene-expression datasets on different aspects of prostate tumorigenesis are available. We used these data to identify and prioritize candidate genes associated with the development of prostate cancer and bone metastases. Our working hypothesis was that combining meta-analyses on different but overlapping steps of prostate tumorigenesis will improve identification of genes associated with prostate cancer development. 相似文献93.
94.
95.
Hasan KM Halphen C Sankar A Eluvathingal TJ Kramer L Stuebing KK Ewing-Cobbs L Fletcher JM 《NeuroImage》2007,34(4):1497-1505
We present and validate a novel diffusion tensor imaging (DTI) approach for segmenting the human whole-brain into partitions representing grey matter (GM), white matter (WM) and cerebrospinal fluid (CSF). The approach utilizes the contrast among tissue types in the DTI anisotropy vs. diffusivity rotational invariant space. The DTI-based whole-brain GM and WM fractions (GMf and WMf) are contrasted with the fractions obtained from conventional magnetic resonance imaging (cMRI) tissue segmentation (or clustering) methods that utilized dual echo (proton density-weighted (PDw)), and spin-spin relaxation-weighted (T2w) contrast, in addition to spin-lattice relaxation weighted (T1w) contrasts acquired in the same imaging session and covering the same volume. In addition to good correspondence with cMRI estimates of brain volume, the DTI-based segmentation approach accurately depicts expected age vs. WM and GM volume-to-total intracranial brain volume percentage trends on the rapidly developing brains of a cohort of 29 children (6-18 years). This approach promises to extend DTI utility to both micro and macrostructural aspects of tissue organization. 相似文献
96.
ROS generated by pollen NADPH oxidase provide a signal that augments antigen-induced allergic airway inflammation
下载免费PDF全文
![点击此处可从《The Journal of clinical investigation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Boldogh I Bacsi A Choudhury BK Dharajiya N Alam R Hazra TK Mitra S Goldblum RM Sur S 《The Journal of clinical investigation》2005,115(8):2169-2179
Pollen exposure induces allergic airway inflammation in sensitized subjects. The role of antigenic pollen proteins in the induction of allergic airway inflammation is well characterized, but the contribution of other constituents in pollen grains to this process is unknown. Here we show that pollen grains and their extracts contain intrinsic NADPH oxidases. The pollen NADPH oxidases rapidly increased the levels of ROS in lung epithelium as well as the amount of oxidized glutathione (GSSG) and 4-hydroxynonenal (4-HNE) in airway-lining fluid. These oxidases, as well as products of oxidative stress (such as GSSG and 4-HNE) generated by these enzymes, induced neutrophil recruitment to the airways independent of the adaptive immune response. Removal of pollen NADPH oxidase activity from the challenge material reduced antigen-induced allergic airway inflammation, the number of mucin-containing cells in airway epithelium, and antigen-specific IgE levels in sensitized mice. Furthermore, challenge with Amb a 1, the major antigen in ragweed pollen extract that does not possess NADPH oxidase activity, induced low-grade allergic airway inflammation. Addition of GSSG or 4-HNE to Amb a 1 challenge material boosted allergic airway inflammation. We propose that oxidative stress generated by pollen NADPH oxidases (signal 1) augments allergic airway inflammation induced by pollen antigen (signal 2). 相似文献
97.
OBJECTIVE: The Centers for Disease Control (CDC) recommends trivalent influenza (TIV) and pneumococcal (PPV) vaccination for eligible hospitalized patients. We conducted a retrospective study comparing two different methods of assessment and its impact on TIV and PPV vaccination in hospitalized patients. DESIGN: Two sequential models were compared in a community hospital for assessing patients' vaccination status and eligibility for TIV and PPV in an inpatient setting. In the first model (Model I), physicians were responsible for assessing eligibility and ordering TIV and/or PPV. In the second model (Model II), nurses were responsible for assessment and vaccination of eligible patients. Charts of hospitalized patients were randomly analyzed for completion rates of the assessment form, rate of vaccination, and documentation of the reason for not vaccinating eligible patients. RESULTS: A total of 138 charts were analyzed for Model I and 168 charts were analyzed for Model II. A significantly higher completion rate for assessment was noted for Model II compared with Model I (79.16% versus 34.78%, P < 0.001 for TIV; 72.02% versus 33.33%, P < 0.001 for PPV). Hospital vaccination rates were not significantly different between the two models for TIV (P = 0.625) and PPV (P = 0.689). A significant percentage of patients refused PPV in Model II [8.03% versus Model I at 3.2% (P = 0.04)]. CONCLUSION: A standing order protocol for assessing hospitalized patients' vaccination status by nursing staff and allowing them to vaccinate eligible patients without depending upon a physician order significantly improved the assessment compliance rate, but not the vaccination rates. Our findings suggest that a system-based method with nursing assessing the need for vaccination and a physician ordering the vaccination would probably have a higher potential for success. 相似文献
98.
Mariacristina Vecchio Sankar D. Navaneethan David W. Johnson Giuseppe Lucisano Giusi Graziano Marialuisa Querques Valeria Saglimbene Marinella Ruospo Carmen Bonifati Emmanuele A. Jannini Giovanni F.M. Strippoli 《Clinical journal of the American Society of Nephrology》2010,5(6):985-995
Background and objectives: Sexual dysfunction is very common in patients with chronic kidney disease (CKD), but treatment options are limited. The benefits and harms of existing interventions for treatment of sexual dysfunction were assessed in patients with CKD.Design, setting, participants, & measurements: MEDLINE (1966 to December 2008), EMBASE (1980 to December 2008), and the Cochrane Trial Registry (Issue 4 2008) were searched for parallel and crossover randomized and quasi-randomized trials. Treatment effects were summarized as mean differences (MD) or standardized mean difference (SMD) with 95% confidence intervals (CI) using a random effects model.Results: Fourteen trials (328 patients) were included. Phosphodiesterase-5 inhibitors (PDE5i) compared with placebo significantly increased the overall International Index of Erectile Function-5 (IIEF-5) score (three trials, 101 patients, MD 1.81, 95% CI 1.51 to 2.10), all of its individual domains, and the complete 15-item IIEF-5 (two trials, 80 patients, MD 10.64, 95% CI 5.32 to 15.96). End-of-treatment testosterone levels were not significantly increased by addition of zinc to dialysate (two trials, 22 patients, SMD 0.19 ng/dl, 95% CI −2.12 to 2.50), but oral zinc improved end-of-treatment testosterone levels. There was no difference in plasma luteinizing and follicle-stimulating hormone level at the end of the study period with zinc therapy.Conclusions: PDE5i and zinc are promising interventions for treating sexual dysfunction in CKD. Evidence supporting their routine use in CKD patients is limited. There is an unmet need for studying interventions for male and female sexual dysfunction in CKD considering the significant disease burden.Sexual dysfunction is a set of disorders characterized by physical and psychologic changes that result in the inability to perform satisfactory sexual activities. The condition has been found to be significantly more common in men and women with chronic kidney disease (CKD) than in the general population (1). Men with CKD frequently suffer from reduced libido, erectile dysfunction, and difficulty reaching orgasm (2). Approximately 50% of male predialysis CKD patients and 80% of male dialysis patients have erectile dysfunction (3–6). Moreover, the prevalence of erectile dysfunction in male dialysis patients has been found to increase with age (63% <50 years versus 90% ≥50 years) (3). Similar results have been reported in women with CKD, with 55% of female dialysis patients reporting difficulty with sexual arousal (2). Dysmenorrhea, delayed sexual development, impaired vaginal lubrication, dyspareunia, and difficulties in reaching orgasm are also frequently observed (7,8).Multiple factors contribute to the frequent occurrence of sexual dysfunction in CKD patients, including hormonal disturbances (such as hyperprolactinemia, hypogonadism in males, and changes in hypothalamic-pituitary function in women) (9), anemia (10), CKD mineral and bone disorder (4), psychosocial factors (such as depression, anxiety, poor self-esteem, social withdrawal, marital discord, body image issues, fear of disability and death, loss of employment, and financial difficulties) (2,11,12), autonomic neuropathy (13), medications (including antihypertensives, antidepressant, and histamine receptor blockers) (2), and comorbid illness (such as diabetes mellitus, cardiovascular disease, and malnutrition) (2,14). Sexual dysfunction is inversely associated with GFR (7) and is improved after renal transplantation (15,16), suggesting that CKD per se may contribute to sexual dysfunction in these patients (15).Studies have also identified significant associations between sexual dysfunction in CKD patients and depression (8,17), impaired quality of life (8,17,18), and adverse cardiovascular outcomes (19). Effective treatment of sexual dysfunction in CKD patients may therefore potentially lead to improvement in these patient-level outcomes, although a causal link has not been definitively established (18).Therapies that have been used to treat sexual dysfunction include phosphodiesterase-5 inhibitors (PDE5i), intracavernosal injections, intraurethral suppositories, hormonal therapy, mechanical devices, and psychotherapy. Although many clinical trials and reviews have explored the role of these interventions for sexual dysfunction in nonuremic patients (20–24), the effectiveness and safety of these interventions in patients with CKD have not yet been studied thoroughly. Therefore, we aimed to evaluate the benefits and harms associated with various interventions for sexual dysfunction in patients with CKD. 相似文献
99.
100.
Sankar V Nareshkumar PN Ajitkumar GN Penmetsa SD Hariharan S 《Current drug delivery》2012,9(5):506-514
The present study investigates the specific drug targeting of anti retroviral drugs, such as lamivudine and zidovudine, after intraperitoneal (i.p) injection by incorporation into polymeric nanoparticles (PNs) and solid lipid nanoparticles (SLNs). Our results showed that Glyceryl Monosterate-Poloxamer 188 SLNs (average diameter of 522.466 nm) showed slow drug release rates (63.18% of lamivudine and 62.37% of zidovudine were released in 12 hrs) among all the SLN formulations. For Poly lactic-co-glycolic acid (PLGA)-Poloxamer 188 PNs (average diameter of 70.348 nm), there were faster release rates of both lamivudine and zidovudine (97% and 94.06%, respectively, in 12 hrs). Tissue distribution studies were carried out in mice and concentrations of drugs in different organs were determined using high performance liquid chromatography (HPLC) after i.p. administration. Glyceryl Monosterate-Poloxamer 188 SLNs and PLGAPoloxamer 188 PNs showed increase in the distribution of lamivudine and zidovudine to liver and spleen when compared to the drugs in solution. Also, Glyceryl Monosterate-P 188 SLNs showed higher concentration of drugs in RES organs than PLGA-P 188 PNs. 相似文献