全文获取类型
收费全文 | 14765篇 |
免费 | 1107篇 |
国内免费 | 547篇 |
专业分类
耳鼻咽喉 | 30篇 |
儿科学 | 61篇 |
妇产科学 | 36篇 |
基础医学 | 1455篇 |
口腔科学 | 311篇 |
临床医学 | 672篇 |
内科学 | 1004篇 |
皮肤病学 | 115篇 |
神经病学 | 1384篇 |
特种医学 | 218篇 |
外国民族医学 | 3篇 |
外科学 | 795篇 |
综合类 | 1426篇 |
现状与发展 | 1篇 |
预防医学 | 260篇 |
眼科学 | 78篇 |
药学 | 6846篇 |
2篇 | |
中国医学 | 1553篇 |
肿瘤学 | 169篇 |
出版年
2023年 | 133篇 |
2022年 | 265篇 |
2021年 | 434篇 |
2020年 | 294篇 |
2019年 | 303篇 |
2018年 | 329篇 |
2017年 | 379篇 |
2016年 | 459篇 |
2015年 | 454篇 |
2014年 | 919篇 |
2013年 | 1429篇 |
2012年 | 839篇 |
2011年 | 856篇 |
2010年 | 621篇 |
2009年 | 644篇 |
2008年 | 660篇 |
2007年 | 700篇 |
2006年 | 566篇 |
2005年 | 507篇 |
2004年 | 408篇 |
2003年 | 398篇 |
2002年 | 326篇 |
2001年 | 279篇 |
2000年 | 283篇 |
1999年 | 268篇 |
1998年 | 244篇 |
1997年 | 250篇 |
1996年 | 215篇 |
1995年 | 217篇 |
1994年 | 195篇 |
1993年 | 194篇 |
1992年 | 184篇 |
1991年 | 167篇 |
1990年 | 185篇 |
1989年 | 168篇 |
1988年 | 146篇 |
1987年 | 127篇 |
1986年 | 144篇 |
1985年 | 161篇 |
1984年 | 161篇 |
1983年 | 124篇 |
1982年 | 156篇 |
1981年 | 141篇 |
1980年 | 107篇 |
1979年 | 79篇 |
1978年 | 73篇 |
1977年 | 50篇 |
1976年 | 50篇 |
1975年 | 26篇 |
1974年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 578 毫秒
1.
《Journal of microbiology, immunology, and infection》2021,54(4):680-686
BackgroundVitamin D is essential in the host defense against tuberculosis (TB). Suboptimal vitamin D status is common in the hemodialysis population. Hemodialysis patients have an increased risk compared to the general population latent tuberculosis infection (LTBI). However, the association between vitamin D deficiency and LTBI in this population remains unclear.Materials and methodsWe conducted a cross-sectional study between March and May 2017. Interferon-gamma release assay (IGRA) through QuantiFERON-TB Gold In-Tube was used to assess LTBI. Plasma 25-hydroxycholecalciferol (25-OHD) levels were measured by Elecsys Vitamin D Total assay. Suboptimal vitamin D levels included vitamin D insufficiency 20–29 ng/mg and vitamin D deficiency <20 ng/mL. Predictors for LTBI were analyzed.ResultsA total of 287 participants were enrolled. The suboptimal vitamin D level was 31.4% (90/287), which including the vitamin D deficiency was 13.9% (40/287). A total of 49.1% (141/287) people received nutritional vitamin D supplementation. The prevalence of IGRA positivity in this study was 25.1% (72/287). There was no significant difference in vitamin D concentrations or the proportion of vitamin D supplementation among the IGRA-positive and IGRA-negative groups (p = 0.789 and 0.496, respectively). In multivariate analysis, age >65 years old (odds ratio (OR), 1.89; 95% CI, 1.08–3.31; p = 0.026) and TB history (OR, 3.51; 95% CI, 1.38–8.91; p = 0.008) were independent predictors of IGRA positivity.ConclusionThis is the first study to report that vitamin D deficiency was not associated with IGRA positivity in a hemodialysis population. Aging and TB history were both independent predictors for LTBI. 相似文献
2.
This study is focussed on micro-encapsulation of essential oils in polylactic acid (PLA) and a poly(methyl methacrylate) (PMMA) matrix as well as blends of the same. Microspheres were prepared by the solvent evaporation technique and characterised by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR). The encapsulation efficiencies and release profiles of the essential oils were studied by gas chromatography mass spectrometry (GC-MS) and head-space solid-phase microextraction GC-MS, respectively. Furthermore, the microspheres were tested for antibacterial activity against both Gram-negative and Gram-positive bacterial strains.
The results showed that the microspheres compositions (PLA/PMMA ratio) have significant effect on their characteristics. The process adopted for preparing the microspheres promoted formation of spherical particles at the sizes of 1.5–9.5?µm. The highest encapsulation efficiency of the prepared microspheres was observed in systems consisting of linalool (81.10?±?10.0?wt. % for PLA system and 76.0?±?3.3?wt. % for PMMA system). Confirmation was also made that the release rate of the microspheres was affected by the size of the same. 相似文献
3.
《Biomaterials》2015
A combination of various therapeutic approaches has emerged as a promising strategy for cancer treatment. A safe and competent nano-delivery system is thus in urgent demand to facilitate the simultaneous transport of various therapeutic agents to cancer cells and a tumor region to achieve synergistic effect. Gold nanoparticles (GNPs) and mesoporous silica nanoparticle (MSNs) were fabricated herein as potential candidates for drug delivery. Serving as gatekeepers, GNPs (5 nm in diameter) were attached onto the amino-functionalized MSNs (denoted as NMSNs) via a relatively weak gold–nitrogen bonding. The resulting nanohybrids (denoted as GCMSNs) were uptaken by cells, and the detachment of GNPs and subsequent intracellular drug release from NMSNs were achieved by competitive binding of intracellular glutathione to GNPs. In addition to the function of gatekeeping, GNPs also play another role as the oxidative stress elicitor. Our in vitro studies revealed that GCMSNs induced higher oxidative stress in lung cancer cells (A549) than in normal cells (3T3-L1). This growth inhibitory effect found in the cancer cells was likely induced by mitochondria dysfunction originated from the GCMSN-induced, oxidative stress-triggered mitochondria-mediated autophagy. The redox-responsive nanohybrids were further loaded with camptothecin and the intensified synergistic therapeutic effects were observed associated with combined chemotherapy and oxidative stress strategy. The results clearly demonstrate that such unique nanohybrids hold great promise for selective and effective cancer treatments. 相似文献
4.
《Journal of cranio-maxillo-facial surgery》2020,48(2):170-175
AimThe purpose of this study was to evaluate the efficiency of pyramidal and posterior osseous release (PPOR) for maxillary impaction using an ultrasonic bone-cutting device after Le Fort I (LFI) osteotomy.Materials and methodsIn total, 31 Japanese adults with jaw deformities, diagnosed as having maxillary excess with mandibular prognathism or deficiency, underwent LFI osteotomy and bilateral sagittal split osteotomy. The patients were divided into two groups: a trimming group (15 patients, four men and 11 women; mean age 24.8 years) and a PPOR group (16 patients, seven men and nine women; mean age 22.8 years). In the trimming group, osseous interference around the descending palatine artery (DPA) was removed using forceps, rounding bur, and reciprocating rasp. The PPOR technique was used to remove osseous fragments created by V-shaped osteotomy around the DPA following vertical osteotomy behind the DPA using an ultrasonic bone-cutting device (Variosurg 3; NSK, Tochigi, Japan). The operative times for maxillary osteotomy, total operative times (including bilateral sagittal split osteotomy), and total blood loss were assessed.ResultsThe mean planned amounts of maxillary impaction were 4.37 ± 1.27 mm in the trimming group and 4.38 ± 1.36 mm in the PPOR group (p = 0.98). The mean maxillary operative time for the PPOR group was significantly shorter, by 25.5% (p < 0.001). Total operative time for the PPOR group was also significantly shorter, by 24.3% (p < 0.001). Mean blood loss was significantly lower in the PPOR group than in the trimming group (p = 0.003).ConclusionThe PPOR technique for maxillary impaction after LFI osteotomy shortened the operative time and enabled secure reduction of the maxilla in patients who required the treatment of maxillary impaction with preservation of the DPA bundle. 相似文献
5.
Marta Rozanski Valentin Neuhaus Emily Thornton Stéphanie J. E. Becker James P. Rathmell David Ring 《Journal of hand and microsurgery》2015,7(1):30-35
This study used the National Survey of Ambulatory Surgery (NSAS) database to measure the incidence of and risk factors for symptoms in the ambulatory surgery center and problems within 24 h after isolated carpal tunnel release (CTR). The NSAS contained records on 400,000 adult patients with carpal tunnel syndrome who were treated with CTR in 2006, based on ICD-9 codes. The type of anesthesia used and factors associated with symptoms and problems were sought in bivariate and multivariable statistical analyses. The mean duration of the procedure was 16 ± 8.8 min. Only 5 % were performed under local anesthesia without sedation, 45 % with IV sedation, 28 % regional anesthesia, and 19 % general anesthesia. Symptoms in the ambulatory surgery center or a problem within 24 h after discharge were recorded in 10 % of patients, all of them minor and transient, including difficulties with pain and its treatment. The strongest risk factors were male sex, age of 45 years and older, and participation of an anesthesiologist. Local anesthesia and regional anesthesia were associated with more perioperative symptoms and postoperative problems. Most CTR are performed with some sedation in the United States. CTR is a safe procedure: one in 10 patients will experience a minor issue in the perioperative or immediate postoperative period. 相似文献
6.
Background
Despite significant pain relief following total hip arthroplasty (THA) in patients with ankylosing spondylitis, a small subset of patients presenting with extra-articular extension contracture of hips remains unsatisfied.Methods
We retrospectively evaluated the patients with ankylosing spondylitis who underwent simultaneous bilateral THA and had extensor tightness of both hips preoperatively. They were managed with modified Z-plasty of iliotibial band. Patients with windswept deformity, commonly seen in bilateral hip arthritis caused by ankylosing spondylitis, were excluded.Results
Between July 2011 and June 2015, out of 148 patients with bilateral hip involvement, 10 patients (20 hips) had extension contracture of both hips that was addressed during surgery. All patients were followed up for a minimum of 2 years. They could sit comfortably on a chair of height 18 inches with hips and knees flexed to at least 90°. The mean postoperative sum range of motion was 144.6° with an average hip flexion of 95° (range, 90°-105°). None of them had recurrence of extension contracture. There was significant improvement in range of motion and hence ambulation and function. No radiolucent lines exceeding 2 mm were seen in any of the zones around either of the components as evaluated in latest X-rays.Conclusion
Extension contracture of hip although rare is a noticeable problem and needs to be addressed during THA. Modified Z-plasty technique of iliotibial band is a reliable method in managing these patients. 相似文献7.
Yeon Seok Lee June Hyunkyung Lee Jae Eun Choi Joo Young Kim Tae Young Han 《Pediatric dermatology》2021,38(1):290-291
Erythema induratum of Bazin (EIB) is a form of tuberculid resulting from hypersensitivity to tuberculosis antigen. EIB occurs most commonly in middle‐aged women and is not typically seen in children. Here, we present a rare case of EIB, presenting as a chronic nodular panniculitis, in a 10‐year‐old Korean boy. 相似文献
8.
9.
《Biomaterials》2015
Mesoporous silica nanoparticles (MSNs) can provide a structural foundation for a new generation of nanocarriers with a broad range of functionalities. Multifunctional MSNs can serve as all-in-one diagnostic and therapeutic tools that can be used to simultaneously visualize and treat various diseases, such as cancer. This research study is the first time that two lanthanide-based imaging systems have been combined to incorporate controlled drug release and targeted tracing into a single MSN-based nano-platform for a novel theranostic drug delivery system. Doping lanthanide ions, i.e., europium (Eu) and gadolinium (Gd) ions, into an MSN structure (EuGd-MSNs) imparts fluorescence and magnetism to the nanostructure that can be used to develop magnetic resonance imaging (MRI) and biological fluorescence tools. Current cancer research has revealed that most human cancer cells express a large number of folate receptors on their surface. Grafting folic acid (FA) onto the EuGd-MSN surface (EuGd-FA-MSNs) imparts a targeting function to the MSN because of the specificity of the binding of FA to cell surface receptors. Furthermore, grafting anticancer drugs, such as camptothecin (CPT), onto the surface of these MSNs by forming disulfide bonds (EuGd-SS-CPT-FA-MSNs) enables intracellular controlled drug release. A high concentration of intracellular glutathione cleaves the disulfide bond to release the drug and treat the disease. The results of in vitro and in vivo studies show that the functionalized MSNs can be successfully used as a platform to integrate dual-imaging, targeting, and therapeutic treatment in multifunctional diagnosis drug delivery systems. 相似文献
10.
《中国现代医生》2020,58(36):103-106+110
目的 对复方倍他米松注射液联合泛昔洛韦胶囊、普瑞巴林胶囊治疗带状疱疹的临床疗效进行观察并探讨。方法 选取2018 年1 月~2019 年12 月我院收治的118 例带状疱疹患者为研究对象,采用随机抽签的方式将患者分为对照组(泛昔洛韦胶囊+普瑞巴林胶囊+甲钴胺片+维生素B1 片)与观察组(联合复方倍他米松注射液),比较两组治疗总有效率、VAS 评分、QS 评分、C 反应蛋白、无新发皮疹时间、结痂时间及疼痛停止时间、随访2 个月后带状疱疹后遗神经痛发生率以及不良反应发生率。结果 观察组与对照组治疗总有效率分别为94.92%及76.27%,组间对比差异有统计学意义(P<0.05);治疗后,观察组VAS 评分显著低于对照组;观察组QS 评分低于对照组(P<0.05);治疗后,观察组C 反应蛋白显著低于对照组(P<0.05);观察组无新发皮疹时间、结痂时间及疼痛停止时间分别显著短于对照组(P<0.05);随访2 个月后,发现观察组带状疱疹后遗神经痛发生率显著低于对照组(P<0.05);观察组不良反应发生与对照组比较,差异无统计学意义(P>0.05)。结论 复方倍他米松注射液联合泛昔洛韦胶囊、普瑞巴林胶囊治疗带状疱疹不仅效果好且安全性高,值得使用。 相似文献