全文获取类型
收费全文 | 3293篇 |
免费 | 272篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 99篇 |
妇产科学 | 74篇 |
基础医学 | 432篇 |
口腔科学 | 84篇 |
临床医学 | 245篇 |
内科学 | 607篇 |
皮肤病学 | 93篇 |
神经病学 | 345篇 |
特种医学 | 100篇 |
外科学 | 481篇 |
综合类 | 94篇 |
一般理论 | 3篇 |
预防医学 | 268篇 |
眼科学 | 110篇 |
药学 | 263篇 |
中国医学 | 22篇 |
肿瘤学 | 215篇 |
出版年
2023年 | 40篇 |
2022年 | 75篇 |
2021年 | 170篇 |
2020年 | 106篇 |
2019年 | 103篇 |
2018年 | 147篇 |
2017年 | 86篇 |
2016年 | 81篇 |
2015年 | 101篇 |
2014年 | 114篇 |
2013年 | 149篇 |
2012年 | 223篇 |
2011年 | 259篇 |
2010年 | 129篇 |
2009年 | 100篇 |
2008年 | 182篇 |
2007年 | 198篇 |
2006年 | 168篇 |
2005年 | 125篇 |
2004年 | 133篇 |
2003年 | 105篇 |
2002年 | 99篇 |
2001年 | 64篇 |
2000年 | 67篇 |
1999年 | 47篇 |
1998年 | 20篇 |
1997年 | 12篇 |
1996年 | 17篇 |
1995年 | 21篇 |
1994年 | 12篇 |
1993年 | 12篇 |
1992年 | 32篇 |
1991年 | 47篇 |
1990年 | 42篇 |
1989年 | 32篇 |
1988年 | 33篇 |
1987年 | 32篇 |
1986年 | 24篇 |
1985年 | 19篇 |
1984年 | 19篇 |
1983年 | 9篇 |
1981年 | 9篇 |
1980年 | 10篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 11篇 |
1976年 | 7篇 |
1975年 | 8篇 |
1970年 | 7篇 |
1968年 | 7篇 |
排序方式: 共有3579条查询结果,搜索用时 31 毫秒
41.
This study was designed to investigate the dose as well as time dependent effects of ethanol on testicular antioxidant defense system in rats. Male Fischer 344 rats were administered ethanol at a dose of 2, 4, and 6 gm/kg orally and control received equal volume of saline and sacrificed 1 h after ethanol ingestion. For time course study, animals were administered ethanol 4 g/kg orally and sacrificed at 1.5, 2, 4, and 6 h after ethanol ingestion. Testicular ethanol concentration increased with increasing doses of ethanol. Copper zinc-superoxide dismutase (CuZn-SOD) activity significantly decreased in the testes of rats treated with increasing doses of ethanol whereas manganese-superoxide dismutase (Mn-SOD) activity significantly increased in a dose dependent manner (181, 186, and 195% of control, respectively). Testicular glutathione (GSH) and malondialdehyde (MDA) levels did not significantly alter with increasing doses of ethanol one hour after ethanol ingestion. Ethanol concentration decreased in the testes with an increase in time after ethanol ingestion. Testicular CuZn-SOD activity significantly decreased whereas Mn-SOD activity increased with an increase in time after ethanol ingestion. Testicular catalase (CAT) activity significantly decreased at 2 h postethanol ingestion. Testicular MDA levels significantly increased at 4 and 6 h after ethanol ingestion indicating that end product of lipid peroxidation. MDA, takes considerable time to form in the testes. A significant decrease in the ratios of CAT/Mn-SOD and glutathione peroxidase (GSH-Px)/Mn-SOD in the testes of rat suggests the ability of mitochondria to scavenge reactive oxygen species (ROS). It is suggested that antioxidant enzyme ratios may be used as an important parameter to determine ethanol induced oxidative stress in the tissues. 相似文献
42.
D Husain M Kramer A G Kenny N Michaud T J Flotte E S Gragoudas J W Miller 《Investigative ophthalmology & visual science》1999,40(10):2322-2331
PURPOSE: To study the long-term effects of photodynamic therapy (PDT), using liposomal benzoporphyrin derivative (BPD) or Verteporfin, on experimental choroidal neovascularization (CNV) and on normal retina and choroid (with no CNV) in the cynomolgus monkey eye. METHODS: Photodynamic therapy was performed in 8 cynomolgus monkey eyes with experimental CNV induced by laser injury. The effect of PDT on normal retina and choroid (with no CNV) was studied in 9 monkey eyes. Liposomal BPD was administered intravenously (0.375 mg/kg) either as a bolus, as a slow infusion over 32 minutes, or as a fast infusion over 10 minutes. Photodynamic therapy was performed using light at a wavelength of 689 or 692 nm, with an irradiance of 600 mW/cm2 and fluence of 150 J/cm2. Follow-up studies, including fundus photography and FA, were performed at 24 hours after PDT and then weekly. Indocyanine green and BPD angiography were performed in selected cases. Tissues were examined with light and electron microscopy at the end of follow-up. RESULTS: Twenty-three of the 32 areas of CNV treated with PDT showed absence of angiographic leakage at 24 hours. Twenty-eight areas of CNV were followed for 4 weeks; 22 of 28 showed absence of angiographic leakage at 2 weeks; and 20 of 28 at 4 weeks of follow-up. Forty spots on the normal retina and choroid were treated with PDT and were followed for 4 to 7 weeks. These spots showed pigment-laden cells in the outer retina, variably pigmented retinal pigment epithelium (RPE) in the treated area, intact neurosensory retina, and reperfusion of the choriocapillaris. CONCLUSIONS: Photodynamic therapy leads to absence of angiographic leakage for at least 4 weeks in experimental CNV in the monkey model. In the normal monkey eye the RPE and choriocapillaris show generalized recovery with preservation of the neurosensory retina 7 weeks after PDT. 相似文献
43.
A strain of CLAVICEPS PURPUREA (F R.) T UL. isolated from ARTHRAXON LANCIFOLIUS H OCHST. was successfully adapted on rye. Experimental cultivation on rye showed 370 kg/ha yield of sclerotia containing 0.5% total alkaloid which consisted of 33% ergometrine, 17.6% ergotamine, 18.7% ergocornine and 22.7% ergokryptine. The results also reveal that alkaloid profile of the ergot strain depends largely on its host. Significantly high yield of the sclerotia and the valuable alkaloid profile of the new strain indicate its commercial potential. 相似文献
44.
Abbreviated course of radiation therapy in older patients with glioblastoma multiforme: a prospective randomized clinical trial. 总被引:9,自引:0,他引:9
W Roa P M A Brasher G Bauman M Anthes E Bruera A Chan B Fisher D Fulton S Gulavita C Hao S Husain A Murtha K Petruk D Stewart P Tai R Urtasun J G Cairncross P Forsyth 《Journal of clinical oncology》2004,22(9):1583-1588
PURPOSE: To prospectively compare standard radiation therapy (RT) with an abbreviated course of RT in older patients with glioblastoma multiforme (GBM). PATIENTS AND METHODS: One hundred patients with GBM, age 60 years or older, were randomly assigned after surgery to receive either standard RT (60 Gy in 30 fractions over 6 weeks) or a shorter course of RT (40 Gy in 15 fractions over 3 weeks). The primary end point was overall survival. The secondary end points were proportionate survival at 6 months, health-related quality of life (HRQoL), and corticosteroid requirement. HRQoL was assessed using the Karnofsky performance status (KPS) and Functional Assessment of Cancer Therapy-Brain (FACT-Br). RESULTS: All patients had died at the time of analysis. Overall survival times measured from randomization were similar at 5.1 months for standard RT versus 5.6 months for the shorter course (log-rank test, P =.57). The survival probabilities at 6 months were also similar at 44.7% for standard RT versus 41.7% for the shorter course (lower-bound 95% CI, -13.7). KPS scores varied markedly but were not significantly different between the two groups (Wilcoxon test, P =.63). Low completion rates of the FACT-Br (45%) precluded meaningful comparisons between the two groups. Of patients completing RT as planned, 49% of patients (standard RT) versus 23% required an increase in posttreatment corticosteroid dosage (chi(2) test, P =.02). CONCLUSION: There is no difference in survival between patients receiving standard RT or short-course RT. In view of the similar KPS scores, decreased increment in corticosteroid requirement, and reduced treatment time, the abbreviated course of RT seems to be a reasonable treatment option for older patients with GBM. 相似文献
45.
Husain M. Gheewala Snehajit Wagh Surajsinh A. Chauhan Sonam M. Devlekar Shruti Bhave Dharmesh J. Balsarkar 《The Indian journal of surgery》2017,79(3):254-255
Blunt abdominal trauma mostly results from motor vehicle accidents, recreational accidents, falls or assaults with commonly injured internal organs being the spleen, liver, retroperitoneum, small bowel, kidneys, bladder, colorectal, diaphragm and pancreas. Gastric rupture is quite uncommon. Isolated gastric perforations following blunt trauma to the abdomen are mostly seen in paediatric patients. It is uncommon in adult patients and even rarer is the occurrence of double gastric perforations. We report here with a case of isolated double gastric perforation in a 24-year-old male patient following vehicular accident. 相似文献
46.
The outcome of randomized controlled trials can vary depending on the eligibility criteria of the patients entering into the trial, as well as the heterogeneity of the eligible population and/or the interventions. If the subject population and/or interventions are heterogeneous, the final outcome of the trial depends on the degree of concordance of effects of the subgroups of interventions on the subgroups of the subject population. The considerations that go into the calculation of sample size and determination of the study stopping rules also would affect the nature of the outcome of the study. In this paper we try to examine these phenomena with respect to the recent trials on endovascular therapy in acute ischemic stroke. 相似文献
47.
Swati Kumari Shikha Tewari Nuzhat Husain Akash Agarwal Anshuman Pandey Ashish Singhal Mohtashim Lohani 《Pathology oncology research : POR》2017,23(1):91-97
Gall bladder Carcinoma (GBC) is the fifth most common cancer of the digestive tract and frequently diagnosed in late stage of disease. Estimation of circulating free DNA (cfDNA) in serum has been applied as a “liquid biopsy” in several deep seated malignancies. Its value in diagnosis of gall bladder carcinoma has not been studied. The present study was designed to assess the role of cfDNA in the diagnosis of GBC and correlate levels with the TNM stage. Serum was collected from 34 patients with GBC and 39 age and sex matched controls including 22 cholecystitis and 17 healthy individuals. Serum cfDNA levels were measured through quantitative polymerase chain reaction (qPCR) by amplification of β-globin gene. Performance of the assay was calculated through the receiver operating characteristic (ROC) curve. The cfDNA level was significantly lower in healthy controls and cholecystitis (89.32 ± 59.76 ng/ml, 174.21 ± 99.93 ng/ml) compared to GBC (1245.91 ± 892.46 ng/ml, p = <0.001). The cfDNA level was significantly associated with TNM stage, lymph node involvement and jaundice (0.002, 0.027, and 0.041, respectively). Area under curve of ROC analysis for cancer group versus healthy and cholecystitis group was 1.00 and 0.983 with sensitivity of 100 %, 88.24 % and specificity of 100 % respectively. Quantitative analysis of cfDNA may distinguish cholecystitis and gall bladder carcinoma and may serve as new diagnostic, noninvasive marker adjunct to imaging for the diagnosis of GBC. 相似文献
48.
49.
Noor Al-Dasooqi Hannah R. Wardill Rachel J Gibson 《Pathology oncology research : POR》2014,20(3):485-491
Chemotherapy for cancer causes significant gut toxicity known as mucositis. The pathogenesis of mucositis is ill defined. Recent clinical research guidelines have highlighted epithelial junctional complexes as emerging targets within mucositis research. Given the robust biological evidence linking tight junctions and matrix metalloproteinases, key mediators of mucositis, tight junction proteins have received significant attention. Despite this, the link between tight junctions, matrix metalloproteinases and mucositis development is yet to be established. This critical review therefore aims to describe the role of matrix metalloproteinases in mucositis, and how matrix metalloproteinase-dependent tight junction disruption may contribute to the pathobiology of mucositis. 相似文献
50.