全文获取类型
收费全文 | 1045篇 |
免费 | 98篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 63篇 |
妇产科学 | 15篇 |
基础医学 | 138篇 |
口腔科学 | 23篇 |
临床医学 | 63篇 |
内科学 | 276篇 |
皮肤病学 | 13篇 |
神经病学 | 58篇 |
特种医学 | 57篇 |
外科学 | 139篇 |
综合类 | 14篇 |
预防医学 | 46篇 |
眼科学 | 70篇 |
药学 | 92篇 |
中国医学 | 3篇 |
肿瘤学 | 81篇 |
出版年
2022年 | 8篇 |
2021年 | 12篇 |
2020年 | 12篇 |
2019年 | 11篇 |
2018年 | 28篇 |
2017年 | 22篇 |
2016年 | 18篇 |
2015年 | 25篇 |
2014年 | 43篇 |
2013年 | 39篇 |
2012年 | 43篇 |
2011年 | 53篇 |
2010年 | 41篇 |
2009年 | 43篇 |
2008年 | 48篇 |
2007年 | 43篇 |
2006年 | 58篇 |
2005年 | 44篇 |
2004年 | 40篇 |
2003年 | 41篇 |
2002年 | 36篇 |
2001年 | 55篇 |
2000年 | 37篇 |
1999年 | 29篇 |
1998年 | 27篇 |
1997年 | 40篇 |
1996年 | 32篇 |
1995年 | 23篇 |
1994年 | 28篇 |
1993年 | 21篇 |
1992年 | 14篇 |
1991年 | 19篇 |
1990年 | 10篇 |
1989年 | 16篇 |
1988年 | 15篇 |
1987年 | 10篇 |
1986年 | 9篇 |
1985年 | 13篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1976年 | 5篇 |
1974年 | 3篇 |
1971年 | 2篇 |
1968年 | 3篇 |
1905年 | 2篇 |
1881年 | 1篇 |
排序方式: 共有1159条查询结果,搜索用时 23 毫秒
81.
Despite improvements in treatment, the 5-year survival for metastatic colorectal cancer remains poor. Novel approaches such as gene immunotherapy are being investigated to improve treatment. Retroviral gene transfer methods have been shown to transduce primary human T lymphocytes effectively resulting in the expression of therapeutic genes. However, a number of defects have been identified in T lymphocytes isolated from patients bearing tumour, which may have critical implications for the development of gene-targeted T cells as an anticancer therapy. To address this issue, primary T lymphocytes were isolated from patients with advanced colorectal cancer and tested for their ability to be transduced and to express subsequently a chimeric immune receptor consisting of a single-chain antibody fragment antigen-binding moiety specific for carcinoembryonic antigen (CEA) fused to the T cell receptor (TCR) CD3zeta chain. In 10 out of 10 patients, T lymphocytes were transduced, expanded in the absence of selection and tested for functional activity against CEA-expressing tumour cells. In each case, functional-specific cytotoxic activity was observed. Negligible activity was found in control cultures. This study highlights the feasibility of patient-derived T lymphocytes as a source of immune cells for autologous gene immunotherapy approaches. 相似文献
82.
We present the case of a female patient in whom acute overt hepatitis developed after 60 days of ketoconazole administration (200 mg/day). A prompt renewed hepatic injury 48 hours after an unintentional rechallenge 30 months later provided definitive evidence for a causative relationship between ketoconazole and acute liver injury. Histological examination revealed acute hepatitis with bridging hepatic necrosis. Clinicians should be aware of this cause and effect relationship between ketoconazole and acute liver injury, which can result in prompt severe acute liver injury after rechallenge. 相似文献
83.
Soluble adhesion molecules and cytokines in tumor-associated tissue eosinophilia of nasopharyngeal carcinoma 总被引:2,自引:0,他引:2
The phenomenon of tumor-associated tissue eosinophilia (TATE) is seen in some cases of nasopharyngeal carcinoma (NPC) and is characterized by the eosinophils breaking through the vascular wall and pervading the tumor stroma. The margination and trans-endothelial migration of eosinophils in a typical inflammatory reaction depend on the activating effects of certain cytokines and the expression of adhesion molecules on the eosinophils and endothelial cells. In order to investigate whether the adhesion molecules and activating cytokines play a role in eosinophil tumor infiltration, we measured the serum levels of 3 adhesion molecules, intercellular adhesion molecule-1, E-selectin and vascular cell adhesion molecule-1, and 2 cytokines, IL-3 and IL-5, in 60 NPC patients and 40 normal healthy subjects. We found that the NPC patients had higher serum levels of all three soluble adhesion molecules than the normal subjects but the levels of adhesion molecules failed to correlate with the TATE phenomenon. The levels of IL-3 and IL-5 appeared not to differ between the NPC and control groups. We postulate that the three soluble adhesion molecules do not play a major role in TATE and that their elevation in serum may be due to local and/or systemic immune responses. 相似文献
84.
85.
The Humphrey optical coherence tomography scanner: quantitative analysis and reproducibility study of the normal human retinal nerve fibre layer
下载免费PDF全文
![点击此处可从《The British journal of ophthalmology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
BACKGROUND/AIMS: To determine the reproducibility of the Humphrey optical coherence tomography scanner (OCT), software version 5.0, for measurement of retinal nerve fibre layer (RNFL) thickness in normal subjects and to compare OCT measurements with published histological thickness of the human RNFL. METHODS: Three independent measurements were obtained at each session for one eye from 15 normal subjects with a mean age of 30.8 (SD 10.9) years. Scans were taken in the peripapillary retina using the default setting (1.74 mm radius from centre of the optic disc) and were repeated 1 week later. Additional scans were obtained at the optic nerve head (ONH) margin overlying the scleral rim, for comparison with available histological data on the human RNFL. RESULTS: For the 1.74 mm circular scan, the mean coefficient of variation (COV) for the global RNFL thickness measurement was 5% (SD 3%). This increased to 8% (3%) for quadrant measurements and to 9% (3%) with further subdivision into 12 segments. Significant differences (p<0.05) between sessions were only found when the data were divided into segments. The mean RNFL thickness for the 1.74 mm scan was 127.87 (9.81) microm. The RNFL was maximal at the superior disc pole, 161.44 microm (14.8), and minimal at the temporal pole, 83.1 (12.8) microm. Peak thickness values occurred superior temporal and inferior temporal to the vertical axis. RNFL thickness for every sector of the disc was greatest at the margin of the optic disc (mean 185.79 microm; SD 32.61). Although the variation in RNFL thickness around the disc follows published histology data, the OCT underestimates RNFL thickness by an average of 37% (SD 11; range 21-48%). CONCLUSION: The OCT provides reproducible measurement of the retinal structures that are consistent with the properties of the RNFL. However, comparison with available studies of RNFL thickness in the human suggests that in its present form, the OCT underestimates RNFL thickness. Further refinement of this technology is required to improve the accuracy with which the OCT measures retinal nerve fibre layer thickness. 相似文献
86.
Genome-wide hypomethylation in hepatocellular carcinogenesis 总被引:19,自引:0,他引:19
87.
Kwak HI Bae MO Lee MH Lee YS Lee BJ Kang KS Chae CH Sung HJ Shin JS Kim JH Mar WC Sheen YY Cho MH 《Environmental toxicology and chemistry / SETAC》2001,20(4):787-795
A number of fish species have been used for studies on endocrine disrupting chemicals (EDCs). However, despite the widespread use of oviparous fish, relatively little attention has been given to viviparous species. This study investigated the effects of EDCs in a viviparous fish and examined the possible usefulness of the fish as an alternative model for the studies on EDCs. Swordtails (Xiphophorus helleri) were exposed to nonylphenol (NP), bisphenol A (BPA), and their mixture. Both short-term (3-d) and relatively long-term (60-d) exposures were carried out using adult male and 30-d-old juvenile fish, respectively. Following the short-term exposure, both NP and BPA caused vitellogenin mRNA expression. Flow cytometric analysis and terminal deoxynucleotidyl transferase assay on the testes of treated fish indicated reproductive damage. Histopathological analysis found degenerative and necrotic cells in seminiferous tubules following the exposure to 100 ppb NP. The testes with lesions were also associated with highly suppressed spermatogenesis. Following the long-term exposure, both NP and BPA exposures significantly affected the growth of swordtails. In all cases, the results showed that the mixture was always more potent than a single chemical and that swordtail fish can be a useful model for the study of endocrine disruptors. 相似文献
88.
Platelet derived growth factor releasing chitosan sponge for periodontal bone regeneration 总被引:35,自引:0,他引:35
With an aim of improving bone regeneration, chitosan sponge containing platelet-derived growth factor-BB (PDGF-BB) were developed. For fabrication of chitosan sponge, chitosan solution was freeze-dried, crosslinked and freeze-dried again. PDGF-BB was incorporated into the chitosan sponge by soaking chitosan sponge into the PDGF-BB solution. Release kinetics of PDGF-BB, cell attachment, proliferation capacity and bony regenerative potentials of PDGF-BB-loaded chitosan sponge were investigated. Prepared chitosan sponge retained porous structure with 100 microm pore diameter that was suitable for cellular migration and growth. Release rate of PDGF-BB could be controlled by varying initial loading content of PDGF-BB to obtain optimal therapeutic efficacy. PDGF-BB-loaded chitosan sponge induced significantly high cell attachment and proliferation level, which indicated good cellular adaptability. PDGF-BB-loaded chitosan sponge demonstrated marked increase in new bone formation and rapid calcification. Degradation of the chitosan sponge was proceeded at defect site and subsequently replaced with new bone. Histomorphometric analysis confirmed that PDGF-BB-loaded chitosan sponge significantly induced new bone formation. These results suggested that chitosan sponge and PDGF-BB-loaded chitosan sponge may be beneficial to enhance periodontal bone regeneration. 相似文献
89.
Herpes zoster oticus is a cranial polyneuropathy with facial nerve involvement as its main feature. The prognosis of the facial palsy is usually poor. Thirty patients with herpes zoster oticus suffering from facial palsy were admitted for parenteral acyclovir and oral prednisolone. Multiple regression analysis of improvement of facial palsy showed three significant covariates: age, multiple nerve palsies, and the initial grading of the palsy. The recovery of the facial palsy treated with acyclovir and prednisolone was good, and possibility of a good outcome was greater when the initial grade of the palsy was higher. Multiple nerve palsies and age had negative effects on the improvement. 相似文献
90.
A term female newborn was noted to have a tumor mass in the oral cavity soon after birth. Oral computer tomography revealed a well-enhanced soft tissue mass about 4 x 4 x 3 cm in size in the left buccal area. Group III embryonal type congenital rhabdomyosarcoma was diagnosed after biopsy (gross removal was not feasible). Respiratory distress exacerbated due to rapid tumor growth compressing airway with the result that endotracheal tube had to be intubated. Chemotherapy was done and complicated by two episodes of neutropenic fever and sepsis. Radiotherapy was suggested but refused by the family. Tumor size was slightly reduced and endotracheal tube could be removed four months later. She was taken home under regular chemotherapy. Radiotherapy, was, however, clearly indicated. 相似文献