全文获取类型
收费全文 | 34320篇 |
免费 | 2370篇 |
国内免费 | 1180篇 |
专业分类
耳鼻咽喉 | 356篇 |
儿科学 | 472篇 |
妇产科学 | 377篇 |
基础医学 | 5225篇 |
口腔科学 | 522篇 |
临床医学 | 3589篇 |
内科学 | 5664篇 |
皮肤病学 | 831篇 |
神经病学 | 2411篇 |
特种医学 | 1907篇 |
外国民族医学 | 5篇 |
外科学 | 3837篇 |
综合类 | 2524篇 |
现状与发展 | 7篇 |
一般理论 | 9篇 |
预防医学 | 1876篇 |
眼科学 | 869篇 |
药学 | 3559篇 |
16篇 | |
中国医学 | 1064篇 |
肿瘤学 | 2750篇 |
出版年
2024年 | 60篇 |
2023年 | 413篇 |
2022年 | 1093篇 |
2021年 | 1509篇 |
2020年 | 862篇 |
2019年 | 951篇 |
2018年 | 1083篇 |
2017年 | 858篇 |
2016年 | 1099篇 |
2015年 | 1531篇 |
2014年 | 1848篇 |
2013年 | 2025篇 |
2012年 | 2850篇 |
2011年 | 2946篇 |
2010年 | 1742篇 |
2009年 | 1465篇 |
2008年 | 2019篇 |
2007年 | 1986篇 |
2006年 | 1698篇 |
2005年 | 1610篇 |
2004年 | 1251篇 |
2003年 | 1062篇 |
2002年 | 892篇 |
2001年 | 720篇 |
2000年 | 742篇 |
1999年 | 598篇 |
1998年 | 341篇 |
1997年 | 298篇 |
1996年 | 237篇 |
1995年 | 222篇 |
1994年 | 179篇 |
1993年 | 154篇 |
1992年 | 170篇 |
1991年 | 187篇 |
1990年 | 152篇 |
1989年 | 155篇 |
1988年 | 119篇 |
1987年 | 110篇 |
1986年 | 97篇 |
1985年 | 71篇 |
1984年 | 53篇 |
1983年 | 49篇 |
1982年 | 57篇 |
1981年 | 35篇 |
1980年 | 35篇 |
1979年 | 37篇 |
1978年 | 22篇 |
1977年 | 32篇 |
1976年 | 41篇 |
1975年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
111.
Objective: To study the pattern of lymphnode metastasis in carcinoma of esophagus. Methods: 200 cases of resected esophageal
cancer specimens were carefully examined pathologically. Lymphnode metastasis, its pathway and extent in relation to pathological
changes were analyzed. Results: Lymphnode metastasis was mainly regional and extended vertically in both directions. Leaping-over
metastasis was another feature. The deeper invasion by the tumor, the higher frequencies of metastasis development, and vice
versa. However, leaping-over metastasis was more likely to occur where tumor invasion was less severe. Conclusion: Owing to
the high frequency of lymphnode metastasis in the superior mediastinum and the widely spanned leaping-over metastasis, an
operative approach by three incisions through right thoracotomy with excision of the whole segment of esophagus and anastomosis
at cervical region was recommended, in order to dissect lymphnodes in the cervical, thoracic and abdominal regions and to
leave less or no metastatic lymphnodes behind. 相似文献
112.
Differential regulation of ciliary neurotrophic factor and its receptor in the rat hippocampus following transient global ischemia 总被引:3,自引:0,他引:3
To investigate a potential role of ciliary neurotrophic factor (CNTF) in transient global ischemia, we have studied the postischemic regulatory changes in the expression of CNTF and its receptor, the ligand-binding alpha-subunit (CNTFRalpha). Immunoblot analysis demonstrated CNTF levels were slightly upregulated already during the first day after ischemia and then increased markedly by more than 10-fold until 2 weeks postischemia. Immunoreactivity for CNTF became detectable 1 day after ischemia and was localized in reactive astrocytes. The intensity of the immunolabeling was maximal in CA1 during the phase of neuronal cell death (days 3-7 postischemia) and in the deafferented inner molecular layer of the dentate gyrus. Upregulation of CNTF expression was less pronounced in CA3 and absent in the stratum lacunosum moleculare and the outer molecular layer of the dentate gyrus and thus did not simply correlate with astroliosis as represented by upregulation of glial fibrillary acidic protein (GFAP). As shown by in situ hybridization, expression of CNTFRalpha mRNA was restricted to neurons of the pyramidal cell and granule cell layers in control animals. Following ischemia, reactive astrocytes, identified by double labeling with antibodies to GFAP, transiently expressed CNTFRalpha mRNA with a maximum around postischemic day 3. This astrocytic response was most pronounced in CA1 and in the hilar part of CA3. These results show that CNTF and its receptor are differentially regulated in activated astrocytes of the postischemic hippocampus, indicating that they are involved in the regulation of astrocytic responses and the neuronal reorganizations occurring after an ischemic insult. 相似文献
113.
Depletion of glutathione in the substantia nigra is one of the earliest changes observed in Parkinson's disease (PD), and could initiate dopaminergic neuronal degeneration. Nevertheless, we have previously demonstrated that mesencephalic dopaminergic neurons in primary monolayer cultures are more resistant to the toxicity of glutathione depletion than nondopaminergic neurons. To extend this finding to a system that more closely resembles the in vivo situation, we characterized the effects of glutathione depletion on reaggregate cultures derived from ventral mesencephalic and their striatal target neurons, as well as supporting elements including glia. Dopaminergic neurons were found to be more resistant to the toxicity of buthionine-(S,R)-sulfoximine, an inhibitor of glutathione synthesis, than other nigrostriatal neurons, while striatal target cells exhibited an intermediate susceptibility when examined after 48 h. Glutathione depletion, however, decreased the intracellular content of catecholamines after 48 h and eventually led to the loss of dopaminergic neurons after 7 days. Our data indicate that the intrinsic resistance of dopaminergic neurons to the toxicity of glutathione depletion occurs in a variety of experimental paradigms, and suggest that global glutathione depletion alone is unlikely to account for the selective loss of dopaminergic neurons in PD. Rather, it is more likely that either the selective loss of glutathione from dopaminergic neurons, or the combination of glutathione loss with other insults contributes to the preferential death of dopaminergic neurons in PD. 相似文献
114.
PURPOSE: Although the intracarotid amobarbital procedure (IAP) or Wada test is useful in lateralizing seizure focus in patients with temporal lobe epilepsy (TLE), the results of the IAP memory test are frequently nonlateralizing. An insufficient suppression of the medial temporal region contralateral to the seizure focus may contribute to the failure of lateralization. We tried to correlate IAP memory results with the functional changes in the contralateral medial temporal region as measured by single photon emission computed tomography (SPECT) during IAP. METHODS: We performed a (99m)technetium-(Tc) hexamethylene-propylene-amine-oxime (HMPAO) brain SPECT in 19 medial TLE patients during a contralateral IAP (sodium amobarbital injected contralateral to the seizure focus). Regional cerebral blood flow (rCBF) was measured in the contralateral medial temporal region. The amount of decrease in the rCBF was calculated by subtracting the previous measurement from the one obtained with the interictal SPECT. RESULTS: Ten (53%) patients passed and nine (47%) failed the contralateral IAP. The mean percentage decrease in rCBF was 5.3+/-5.3%. There was a significant negative correlation between a decrease in the rCBF and the IAP memory-retention score by Spearman correlation (p = -0.53: p<0.021). Patients with smaller decreases in rCBF (<5%) more frequently passed the contralateral IAP memory test than did those with larger decreases (80 vs. 22%; p<0.023). CONCLUSIONS: We suggest that an insufficient suppression of the contralateral medial temporal function is partly responsible for nonlateralizing IAP memory tests. An IAP-SPECT may be useful in interpreting IAP memory tests for the lateralization of seizure focus in TLE patients. 相似文献
115.
目的:观察3g/L盐酸洛美沙星眼凝胶的临床疗效及安全性。方法:对128例(203眼)细菌性结膜炎和细菌性角膜炎患者采用多中心、随机分组、平行对照试验,观察其主要症状体征消失情况、角膜炎症面积缩小情况、病原菌清除效果和不良反应。试验组(testgroup,TG)65例(103眼),对照组(controlledgroup,CG)63例100眼,分别应用3g/L盐酸洛美沙星眼凝胶和3g/L盐酸洛美沙星滴眼液。结果:①TG治愈率(80.6%)高于CG治愈率(65.0%);②TG(细菌性结膜炎)眼痛异物感消失率和消失时间(83.7%,5.33±2.00d)优于CG(64.1%,6.36±1.50d);TG(细菌性结膜炎)流泪消失率(91.8%)高于CG(75.0%);③记分统计表明:TG(细菌性结膜炎)结膜充血改善(平均下降1.76分)明显优于CG(平均下降1.25分);TG畏光消失情况(平均下降1.24分)好于CG(平均下降0.87分);TG(细菌性结膜炎)分泌物消失情况(平均下降1.64分)好于CG(平均下降1.33分);④其他情况两组间无明显差异。结论:3g/L盐酸洛美沙星眼凝胶治疗眼前段细菌感染安全、有效,对结膜炎症状体征的改善优于滴眼液。 相似文献
116.
Kang R Ghivizzani SC Muzzonigro TS Herndon JH Robbins PD Evans CH 《Clinical orthopaedics and related research》2000,(375):324-337
Gene therapy offers new possibilities for the clinical management of orthopaedic conditions that are difficult to treat by traditional surgical or medical means. To bring the potential of this novel technology into the clinic, a research program was initiated that aimed to identify orthopaedically useful genes and develop methods for delivering them to suitable sites under conditions in which gene expression remains at therapeutic levels for the appropriate periods of time; this program is now 10 years old. Rheumatoid arthritis was selected as the lead disease. Preclinical studies evaluating the local and systemic delivery of numerous different genes by in vivo and ex vivo methods in murine and lapin models led to the development of a human gene therapy protocol for arthritis. In this protocol, a gene encoding the human interleukin-1 receptor antagonist protein is transferred to the metacarpophalangeal joints of female patients with rheumatoid arthritis. The first patient was treated this way in July 1996. This is not only the first orthopaedic application of human gene therapy, but also the first use of gene therapy approved for a nonlethal disease. In addition to providing additional therapeutic options for the treatment of rheumatoid arthritis, the experimental data from this study suggest that gene transfer approaches may improve the treatment of osteoarthritis, the repair of cartilage, ligaments, tendons, menisci, intervertebral discs and bone, and the management of disorders such as osteoporosis and osteogenesis imperfecta. They also show promise as a means for developing novel and improved animal models of orthopaedic diseases. If the current rate of progress continues, wide clinical application of gene therapy in various orthopaedic indications should occur within the next 5 to 10 years. 相似文献
117.
118.
A Rose S Roy V Abraham G Holmgren K George V Balraj S Abraham J Muliyil A Joseph G Kang 《Archives of disease in childhood》2006,91(2):139-141
AIMS: To evaluate the efficacy and acceptability of solar irradiation in the prevention of diarrhoeal morbidity in children under 5 years of age, in an urban slum in Vellore, Tamil Nadu. METHODS: A total of 100 children were assigned to receive drinking water that had been subjected to solar disinfection in polyethylene terephthalate bottles. One hundred age and sex matched controls were also selected. Both groups were followed by weekly home visits for a period of six months for any diarrhoeal morbidity. At the end of the follow up period, the acceptability of the intervention was assessed by interviews, questionnaires, and focus group discussions. RESULTS: There was significant reduction in the incidence, duration, and severity of diarrhoea in children receiving solar disinfected water, despite 86% of the children drinking water other than that treated by the intervention. The incidence of diarrhoea in the intervention group was 1.7 per child-year, and among controls 2.7 per child-year, with an incidence rate ratio of 0.64 (95% CI -0.48 to 0.86). The risk of diarrhoea was reduced by 40% by using solar disinfection. In qualitative evaluation of acceptability, most women felt that solar disinfection was a feasible and sustainable method of disinfecting water. CONCLUSIONS: Solar disinfection of water is an inexpensive, effective, and acceptable method of increasing water safety in a resource limited environment, and can significantly decrease diarrhoeal morbidity in children. 相似文献
119.
介绍了一种基于计算机动画和视频剪辑技术的心律失常教学课件的设计思想、课件内容及演示特点。 相似文献
120.
Vascular endothelial growth factor gene polymorphisms and risk of primary lung cancer. 总被引:17,自引:0,他引:17
Su Jeong Lee Sin Yeob Lee Hyo-Sung Jeon Sun Ha Park Jin Sung Jang Ga Young Lee Ji Woong Son Chang Ho Kim Won Kee Lee Sin Kam Rang Woon Park Tae-In Park Young Mo Kang In-San Kim Tae Hoon Jung Jae Yong Park 《Cancer epidemiology, biomarkers & prevention》2005,14(3):571-575
Angiogenesis is an essential process in the development, growth, and metastasis of malignant tumors including lung cancer. DNA sequence variations in the vascular endothelial growth factor (VEGF) gene may lead to altered VEGF production and/or activity, thereby causing interindividual differences in the susceptibility to lung cancer via their actions on the pathways of tumor angiogenesis. To test this hypothesis, we investigated the potential association between three VEGF polymorphisms (-460T > C, +405C > G, and 936C > T)/haplotypes and the risk of lung cancer in a Korean population. VEGF genotypes were determined in 432 lung cancer patients and 432 healthy controls that were frequency matched for age and sex. VEGF haplotypes were predicted using Bayesian algorithm in the phase program. Compared with the combined +405 CC and CG genotype, the +405 GG genotype found associated with a significantly decreased risk of small cell carcinoma [SCC; adjusted odds ratio (OR), 0.36; 95% confidence interval (95% CI), 0.17-0.78]. The 936 CT genotype and the combined 936 CT and TT genotype were also associated with a significantly decreased risk of SCC compared with the 936 CC genotype (adjusted OR, 0.47; 95% CI, 0.26-0.85 and adjusted OR, 0.44; 95% CI, 0.24-0.80, respectively). Haplotype CGT was associated with a significantly decreased risk of SCC (adjusted OR, 0.39; 95% CI, 0.18-0.87), whereas haplotype TCC conferred a significantly increased risk of SCC (adjusted OR, 1.63; 95% CI, 1.14-2.33). None of the VEGF polymorphisms studied significantly influenced the susceptibility to lung cancer except SCC. However, haplotypes TCT and TGT were significantly associated with the risk of overall lung cancer, respectively (adjusted OR, 0.38; 95% CI, 0.25-0.60 and adjusted OR, 3.94; 95% CI, 2.00-7.76, respectively). These effects of haplotypes TCT and TGT on lung cancer risk were observed in three major histologic types of lung cancer. These results suggest that the VEGF gene may be contribute to an inherited predisposition to lung cancer. 相似文献