全文获取类型
收费全文 | 17081篇 |
免费 | 1470篇 |
国内免费 | 924篇 |
专业分类
耳鼻咽喉 | 153篇 |
儿科学 | 200篇 |
妇产科学 | 330篇 |
基础医学 | 2101篇 |
口腔科学 | 411篇 |
临床医学 | 2261篇 |
内科学 | 2661篇 |
皮肤病学 | 246篇 |
神经病学 | 877篇 |
特种医学 | 477篇 |
外国民族医学 | 7篇 |
外科学 | 1843篇 |
综合类 | 2487篇 |
现状与发展 | 1篇 |
一般理论 | 11篇 |
预防医学 | 960篇 |
眼科学 | 423篇 |
药学 | 1756篇 |
9篇 | |
中国医学 | 708篇 |
肿瘤学 | 1553篇 |
出版年
2024年 | 63篇 |
2023年 | 277篇 |
2022年 | 638篇 |
2021年 | 750篇 |
2020年 | 557篇 |
2019年 | 546篇 |
2018年 | 594篇 |
2017年 | 487篇 |
2016年 | 452篇 |
2015年 | 731篇 |
2014年 | 913篇 |
2013年 | 925篇 |
2012年 | 1313篇 |
2011年 | 1439篇 |
2010年 | 908篇 |
2009年 | 712篇 |
2008年 | 891篇 |
2007年 | 916篇 |
2006年 | 866篇 |
2005年 | 836篇 |
2004年 | 589篇 |
2003年 | 570篇 |
2002年 | 409篇 |
2001年 | 385篇 |
2000年 | 382篇 |
1999年 | 449篇 |
1998年 | 267篇 |
1997年 | 264篇 |
1996年 | 183篇 |
1995年 | 167篇 |
1994年 | 140篇 |
1993年 | 101篇 |
1992年 | 112篇 |
1991年 | 88篇 |
1990年 | 77篇 |
1989年 | 61篇 |
1988年 | 88篇 |
1987年 | 77篇 |
1986年 | 45篇 |
1985年 | 44篇 |
1984年 | 22篇 |
1983年 | 20篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 8篇 |
1979年 | 28篇 |
1978年 | 9篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1972年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 37 毫秒
101.
ObjectiveStudies have shown that some specific body measures are associated with the occurrence of cancers. Few studies have demonstrated the relationship with more comprehensive approaches. This study aims to explore body measures and the combinations associated with internal organ cancers.MethodsThree-dimensional anthropometric body surface scanning data collected 10,215 participants from the health examination department in a medical center of Taiwan during 2000–2010. Follow-up was conducted for an average of 8 years, and 244 internal organ cancer cases were identified.ResultsAn increased risk of internal organ cancers was observed among the subjects with larger waist circumference/smaller thigh circumference, in which waist-to-thigh ratio (WTR) was constructed. Comparing the subjects in the fourth quartile for WTR to the subjects in the first quartile with multiple Cox regression analysis yielded a hazard ratio of 1.842 (95% confidence interval, 1.131~2.999). The association between WTR quartile and internal organ cancers was stronger among male participants, older participants, and participants with chronic conditions.ConclusionsThe study has revealed that WTR is the most significant predictor for the occurrence of cancer in Asian populations. Because it is easy to measure and open to modification, WTR may be more useful in clinical and preventive medicine in the future. 相似文献
102.
目的研究不同缺氧方式预处理对心肌细胞线粒体功能的影响,为探讨心肌缺血缺氧病理生理过程中的一些现象提供依据。方法原代培养乳鼠心肌细胞,经过几种不同的缺氧预处理后,继续培养24h,再次给予较严重的缺氧损伤处理,在不同钓时间点用用流式细胞仪检测罗丹明123标记线粒体的膜电位。结果Ⅰ组和Ⅱ组在缺氧预处理后的荧光强度通过成组t检验。t=10.16,P〈0.05;Ⅰ组和Ⅱ组在24h后再次经过缺氧损伤后荧光强度通过成组t检验,t=6.23,P〈0.05;Ⅰ组和Ⅲ组在缺氧预处理后的荧光强度通过成组t检验,t=34.12,P〈0.05;Ⅰ组和Ⅲ组在24h后再次经过缺氧损伤后荧光强度通过成组t检验,t=18.84.P〈0.05;Ⅰ组和Ⅳ组在缺氧预处理后的荧光强度通过成组t检验,t=26.25,P〈0.05;Ⅰ组和Ⅳ组在24h后再次经过缺氧损伤后荧光强度通过成组t检验,t=17.69,P〈0.05。再次损伤后Ⅱ组的细胞线粒体内的电位较对照组高。Ⅲ组和Ⅳ组的细胞线粒体内的电位明显较对照组低。结论在经过不同方式的缺氧预处理后,心肌细胞对再次严重缺氧损伤的反应性是不同的。预处理后的心肌细胞可以对再次损伤的抵抗力增强,即产生了我们所认识的预适应保护效应;也能产生心肌细胞对再次损伤的抵抗力减弱,即产生了我们所认识的缺氧损伤增敏效应。 相似文献
103.
摘 要 目的:考察影响水杨酸滴丸制备的因素,确立其最佳成型工艺。方法: 考察环境因素、加热温度、基质配比与试验步骤对滴丸制备工艺的影响。以丸重差异、溶出时限及外观质量为综合评价指标,通过正交试验进一步优化滴丸的制备工艺。结果: 基质单独加热熔化后再与药液在避光密封的条件下进行混合,可防止药液迅速氧化变红。滴丸的最佳制备工艺为:聚乙二醇400与聚乙二醇6000的比例为1∶5,药液温度为50℃,滴距为8 cm,滴制速度为70滴·min-1。结论:该工艺简单可行,制得滴丸的丸重差异、溶出时限及外观质量均符合质量要求。 相似文献
104.
背景:颈椎前路椎间盘切除减压融合内固定已成为目前临床上常用的手术,但是传统融合器的上下弧度难以与上下终板保持完全一致,容易引起椎间融合器沉降等一系列相关并发症,作者所在课题组研究出与上下终板保持一致的新型颈椎3D打印多孔椎间融合器.目的:通过三维有限元分析法评价新型颈椎3D打印多孔椎间融合器的力学特点,为临床应用和进一... 相似文献
105.
Apolipoprotein E mRNA is abundant in the brain and adrenals, as well as in the liver, and is present in other peripheral tissues of rats and marmosets. 总被引:28,自引:9,他引:28 下载免费PDF全文
N A Elshourbagy W S Liao R W Mahley J M Taylor 《Proceedings of the National Academy of Sciences of the United States of America》1985,82(1):203-207
The relative amount of apolipoprotein (apo-) E mRNA in 12 different tissues of the rat and marmoset was examined by dot blot hybridization using cloned cDNA probes. As expected, it was found to be most abundant in the liver. However, substantial amounts of apo-E mRNA were found in the brain and adrenals at relative levels about one-third of that found in the liver. Significant quantities of apo-E mRNA were detected in all of the other peripheral tissues as well. The apo-E mRNA levels in these tissues were 2-10% of that found in the liver of the rat and 10-30% of that found in the liver of the marmoset. Apo-E mRNA was also abundant in human brain and in each species examined; it was distributed throughout all major areas of this organ. In contrast, apo-A-I mRNA was detected in abundant amounts only in the small intestine and in the liver. Extrahepatic apo-E mRNA appears to be functional, generating a translation product similar or identical to that generated by the liver. During fetal and neonatal development, apo-E mRNA is rapidly induced from low levels to approximately equal to 60% of adult levels in liver at parturition. The fetal yolk sac contains more apo-E mRNA than the fetal liver, suggesting a significant role for the yolk sac as a source of apo-E during gestation. 相似文献
106.
S Liao D Witte 《Proceedings of the National Academy of Sciences of the United States of America》1985,82(24):8345-8348
Circulating autoantibodies to human and rat androgen receptors are present at high titers in the blood sera of some patients with prostate diseases. The antibodies from some serum samples were associated with a purified IgG fraction and interacted with the 3.8S cytosolic androgen-receptor complexes of rat ventral prostate to form 9- to 12S units. Other serum samples, however, formed 14- to 19S units, suggesting that other immunoglobulins might be involved. In the presence of an anti-human immunoglobulin as a second antibody, the androgen-receptor-antibody complexes could be immunoprecipitated. The antibodies interacted with the nuclear and the cytosolic androgen-receptor complexes, either the DNA-binding or the nonbinding form, but not with receptors for estradiol, progestin, or dexamethasone from a variety of sources. Human testosterone/estradiol-binding globulin, rat epididymal androgen-binding protein, or rat prostate alpha-protein (a nonreceptor steroid-binding protein) also did not interact with the antibodies to form immunoprecipitates. About 37% of male and 3% of female serum samples screened had significant antibody titer. The chance of finding serum with a high titer is much better in males older than 66 years than in the younger males or females at all ages. The presence of the high-titer antibodies may make it possible to prepare monoclonal antibodies to androgen receptors without purification of the receptors for immunization. 相似文献
107.
目的 观察左旋精氨酸(LArginine,LArg) 对离体兔肺脏保存的保护作用。 方法 30 只健康家兔随机分成对照组和左旋精氨酸组(LArg 组) ,每组15 只,对照组兔肺脏给予Eurocollins 液进行灌注,LArg 组给予含LArg的Eurocollins 液进行灌注,灌注总量60ml/kg ,灌注压力1 .96kPa(20cm H2 O) ,灌注完毕整取下心肺组织浸入4 ℃保存液中冷藏,7 小时后取肺进行离体复灌,测定肺血管阻力、血气分析、肺血管对乙酰胆碱舒血管反应性、肺组织湿/ 干重比例及肺组织电子显微镜检查等指标。 结果 对照组肺血管阻力、肺组织湿/ 干重比例均高于LArg 组( P< 0 .05) ,肺血管对乙酰胆碱反应性对照组较LArg 组差, 血气分析肺静脉血氧分压对照组下降明显( P < 0-01) ,LArg 组肺组织形态轻微改变,而对照组肺组织水肿明显、渗出严重。 结论 LArg具有改善离体兔肺脏的保存效果。 相似文献
108.
5-氟尿嘧啶在胰十二指肠切除术患者血液和胰液中的动态分布 总被引:3,自引:0,他引:3
探讨5-氟尿嘧啶能否通过胰十二指肠切除术后的残留胰腺组织进入胰液中,并达有效的治疗浓度,为胰腺为临床合理化疗提供理论依据。方法通过观察胰十二指肠切除术患者胰快速推注5-氟尿嘧啶后血液和胰液中药物动态分布及相关性,术后静脉一次性快速推注5-氟尿嘧啶1.0g/m^2,在给药前后按设计时间点分别采集静脉血和胰液,采用高效液相色谱法测定血浆和胰液5-氟尿嘧啶药物浓度,应用PCNONLIN程序程序计算共动态 相似文献
109.
To understand the effects of skeletal size of the lumbar spine on areal bone mineral density (aBMD), volumetric bone mineral density (vBMD), and the diagnosis of osteoporosis in postmenopausal women, we measured the projected bone area, bone mineral content (BMC), aBMD, and vBMD at the anteroposterior and lateral lumbar spines in a population of 1081 postmenopausal Chinese women, 42 to 86 years of age. The results indicated that, at the anteroposterior and lateral lumbar spine, there were significant positive correlations between bone area and both BMC (r = 0.606; P = 0.000 and r = 0.610; P = 0.000) and aBMD (r = 0.270; P = 0.000 and r = 0.182; P = 0.000), but not vBMD (r = –0.055; P = 0.000 and r = 0.000; P = 0.929). When bone area at the anteroposterior spine changed by ±1 SD, the BMC, aBMD, and vBMD correspondingly changed by 28.2%, 10.1%, and 1.69% on the basis of their respective means. When a variation of ±1 SD was observed in bone area at the lateral spine, BMC and aBMD, correspondingly changed by 25.9% and 6.18% on the basis of their respective means, while vBMD indicated no change. Through comparisons among large-, intermediate-, and small-bone area groups, significant differences were found in the means of subjects heights, weights, BMC, and vBMD at the anteroposterior and lateral lumbar spines, as well as in the detection rates of osteoporosis by aBMD (P = 0.000). Detection rates of osteoporosis by aBMD at the anteroposterior spine and by aBMD at the lateral spine, and by vBMD were 44.1%, 55.5%, and 49.7%, respectively, in the total population; 31.4%, 41.7%, and 53.7%, respectively, in the large-bone area group; 43.3%, 55.9%, and 50.5%, respectively, in the intermediate-bone area group; and 61.7%, 70.0%, and 42.5%, respectively, in the small-bone area group. No significant differences were found in the detection rates of osteoporosis by vBMD among the groups. The results of multiple linear regression revealed that the major factors influencing skeletal size and aBMD of the lumbar spine were height and weight. Therefore, in menopausal women of the same ethnic group and age, the skeletal size of the lumbar spine would have significant influence upon aBMD and the diagnosis of osteoporosis, i.e., the larger the spinal size, the greater the aBMD and the lower the osteoporosis detection rate, while, conversely, the smaller the skeletal size, the smaller the aBMD and the higher the osteoporosis detection rate. When we use aBMD of the lumbar spine to diagnose osteoporosis in a population with different body sizes, we need to take this body size difference into account. When we use vBMD to diagnose osteoporosis, the effect of body size on BMD will diminish. 相似文献
110.
人半月板纤维软骨细胞培养及生物学特性研究 总被引:2,自引:0,他引:2
为探索分离培养人半月板纤维软骨细胞的简便实用方法,采用胰蛋白酶和胶原酶联合消化的方法,简便快速地获得大量成活率高的人半月板纤维软骨细胞,在F-12培养液中进行原代和传代培养,并对传代培养纤维软骨细胞进行了免疫组化鉴定,光镜及超微结构的观察,结果显示,光镜下,原代培养细胞呈线形,单层排列,电镜可见细胞内有丰富的粗面内质网及线粒体,细胞呈多极性,表面有突起,纤维软骨细胞免疫组化Ⅱ型胶原染色阳性,提示本实验建立的人纤维软骨细胞分离培养方法是一种可行的方法。, 相似文献