全文获取类型
收费全文 | 12883篇 |
免费 | 1224篇 |
国内免费 | 319篇 |
专业分类
耳鼻咽喉 | 106篇 |
儿科学 | 191篇 |
妇产科学 | 140篇 |
基础医学 | 1816篇 |
口腔科学 | 311篇 |
临床医学 | 1178篇 |
内科学 | 1417篇 |
皮肤病学 | 196篇 |
神经病学 | 879篇 |
特种医学 | 510篇 |
外科学 | 2905篇 |
综合类 | 1479篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 1138篇 |
眼科学 | 165篇 |
药学 | 677篇 |
13篇 | |
中国医学 | 582篇 |
肿瘤学 | 721篇 |
出版年
2024年 | 24篇 |
2023年 | 280篇 |
2022年 | 465篇 |
2021年 | 669篇 |
2020年 | 684篇 |
2019年 | 568篇 |
2018年 | 555篇 |
2017年 | 546篇 |
2016年 | 481篇 |
2015年 | 499篇 |
2014年 | 772篇 |
2013年 | 851篇 |
2012年 | 642篇 |
2011年 | 1716篇 |
2010年 | 672篇 |
2009年 | 713篇 |
2008年 | 608篇 |
2007年 | 474篇 |
2006年 | 427篇 |
2005年 | 362篇 |
2004年 | 307篇 |
2003年 | 270篇 |
2002年 | 230篇 |
2001年 | 196篇 |
2000年 | 164篇 |
1999年 | 156篇 |
1998年 | 121篇 |
1997年 | 104篇 |
1996年 | 97篇 |
1995年 | 104篇 |
1994年 | 90篇 |
1993年 | 69篇 |
1992年 | 54篇 |
1991年 | 48篇 |
1990年 | 50篇 |
1989年 | 43篇 |
1988年 | 44篇 |
1987年 | 40篇 |
1986年 | 33篇 |
1985年 | 45篇 |
1984年 | 26篇 |
1983年 | 18篇 |
1982年 | 21篇 |
1981年 | 15篇 |
1980年 | 24篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1976年 | 12篇 |
1975年 | 5篇 |
1974年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
11.
目的本研究以护理结局分类(NOC)为基础,筛选符合慢性心力衰竭患者的相关护理结局,由此构建具有专科专病特点的慢性心力衰竭患者护理结局评价表。方法成立研究核心小组,应用文献回顾法、专家函询法确定护理结局分类指标,并进行统计学分析,最终建立慢性心力衰竭护理结局分类评价表。结果通过研究,确定慢性心力衰竭护理结局中包含4个领域、8个一级指标、68个二级指标。4个领域分别是生理健康、功能健康、健康知识和行为、心理社会健康。一级指标中包含心脏泵血功能、活动耐力、社会支持、抑郁水平等。二级指标中包含心脏指数、血压、呼吸困难、情绪波动大、步行距离、步行速度等68个指标。统计学分析中:第一、二轮函询专家的积极系数分别为90%、100%,专家权威系数为0.895,专家意见协调程度(P<0.05)。结论本研究成功建立慢性心力衰竭护理结局分类评价表,有助于临床护士用于评价护理措施的有效性,也使其成为一种标准化语言,便于应用到护理电子信息系统中进行绩效测算等。但是本研究不足之处是未能将该研究进行临床实证,未能进一步确认其有效性。 相似文献
12.
13.
The objective of this study was to investigate the absorption behavior of chikusetsusaponin IVa (CHS‐IVa) in the rat intestine using single‐pass intestinal perfusion (SPIP) and to classify CHS‐IVa into the biopharmaceutics classification system (BCS). The equilibrium solubility of CHS‐IVa was determined by the shaker method. The absorption mechanism of CHS‐IVa in the intestine was studied by comparing the Peff of different concentrations of CHS‐IVa. The intestinal site dependence of CHS‐IVa absorption was studied by comparing the Peff of the same concentration of CHS‐IVa in different intestinal segments. The relationship between CHS‐IVa and intestinal efflux protein was studied by perfusion with an efflux protein inhibitor. The permeability of CHS‐IVa was investigated by comparing the Peff of CHS‐IVa and the reported value. The solubility of CHS‐IVa over the pH range 1.0–7.5 was 14.4 ± 0.29 to 16.9 ± 0.34 mg/ml. The Peff of CHS‐IVa in the duodenum was 1.76 × 10?3 to 2.00 × 10?3 cm/min. The Peff of CHS‐IVa in the jejunum was 1.26 × 10?3 to 1.39 × 10?3 cm/min. The Peff of CHS‐IVa in the ileum was 1.25 × 10?3 to 1.31 × 10?3 cm/min. The Peff of CHS‐IVa in the colon was 1.02 × 10?3 to 1.08 × 10?3 cm/min. There was no statistical difference of the Peff in the four segments at different CHS‐IVa concentrations. The Peff of CHS‐IVa (0.07, 0.7 and 7.0 mg/ml) were all notably smaller than the reported Peff (3.00 × 10?3 cm/min) in the jejunum. The Peff of CHS‐IVa was not influenced by verapamil (P‐gp inhibitor), indomethacin (MRP inhibitor) and pantoprazole (BCRP inhibitor). CHS‐IVa was classified as high solubility, low permeability and BCS III. The main absorptive tracts were the upper intestinal tracts and the rank order of intestinal permeability was duodenum > jejunum ≈ ileum > colon. The transport mechanism of CHS‐IVa in all intestinal segments might be primarily passive transport. CHS‐IVa was not a substrate of P‐gp, MRP and BCRP. 相似文献
14.
15.
Mahwash Kassi Venkateshwar Polsani Robert C. Schutt Solomon Wong Faisal Nabi Michael J. Reardon Dipan J. Shah 《The Journal of thoracic and cardiovascular surgery》2019,157(5):1912-1922.e2
Background
The purpose of this analysis is to describe the differences in cardiac magnetic resonance characteristics between benign and malignant tumors, which would be helpful for surgical planning.Methods
This was a prospective cohort study of 130 patients who underwent cardiac magnetic resonance imaging for evaluation of a suspected cardiac mass. After excluding thrombi and tumors without definitive diagnosis, 66 tumors were evaluated for morphologic features and tissue composition.Results
Of the 66 patients, 39 (59.0%) had malignant tumors and 27 (41.0%) had benign tumors. Patients with malignant tumors were younger when compared with those with benign tumors (age 51 years [42.8-60.0] vs 65 years [60.0-71.0] median). Malignant tumors more often demonstrated tumor invasion (69% vs 0% P < .001) and were more often associated with pericardial effusion (41% vs 7.4% P = .004). Presence of first-pass perfusion (100% vs 33% P < .001) and late gadolinium enhancement (100% vs 59.2%, P < .001) were significantly higher in malignant tumors. In logistic regression modeling, tumor invasion (P < .001) and first-pass perfusion (P < .001) were independently associated with malignancy. Furthermore, using classification and regression tree analysis, we developed a decision tree algorithm to help differentiate benign from malignant tumors (diagnostic accuracy ~90%). The algorithm-weighted cost of misclassifying a malignant tumor as benign was twice that of classifying a benign tumor as malignant.Conclusions
Our study demonstrates that cardiac magnetic resonance imaging is a useful noninvasive method for differentiating malignant from benign cardiac tumors. Tumor size, invasion, and first-pass perfusion were useful imaging characteristics in differentiating benign from malignant tumors. 相似文献16.
Roberto De la Plaza Llamas Jos M Ramia 《World journal of gastroenterology : WJG》2020,26(21):2682-2690
Postoperative complications(PC) are a basic health outcome, but no surgery service in the world records and/or audits the PC associated with all the surgical procedures it performs. Most studies that have assessed the cost of PC suffer from poor quality and a lack of transparency and consistency. The payment system in place often rewards the volume of services provided rather than the quality of patients' clinical outcomes. Without a thorough registration of PC, the economic costs involved cannot be determined. An accurate, reliable appraisal would help identify areas for investment in order to reduce the incidence of PC,improve surgical results, and bring down the economic costs. This article describes how to quantify and classify PC using the Clavien-Dindo classification and the comprehensive complication index, discusses the perspectives from which economic evaluations are performed and the minimum postoperative follow-up established, and makes various recommendations. The availability of accurate and impartially audited data on PC will help reduce their incidence and bring down costs. Patients, the health authorities, and society as a whole are sure to benefit. 相似文献
17.
J. de Pedro-Cuesta V. Abraira G.-X. Jiang G. Solders S. Fredrikson 《Acta neurologica Scandinavica》1996,93(2-3):175-183
Using hierarchical cluster analysis, applied to 47 cases of Guillain-Barre Syndrome (GBS) incident in South-West Stockholm (SWS) during the period from January 1973 to June 1992, we identified three major clinicoepidemiological subgroups. The first subgroup, 25.5% of the cases (26.7 ± 6.7 years), recorded a peak incidence at ages 20–29 years and presented significant differences from other subgroups, a high proportion of cases with onset at low age preceded by respiratory infection (83.3%) and with normal motor conduction velocity (50.0%). Also found, were less affected biological parameters, a rapidly progressive course and independence in gait at one month after onset. A second subgroup, 27.7% of cases, was severely affected, clinically and functionally. It consisted predominantly of young individuals (22.7 ± 11.1 years), with a high incidence (69.2% of cases) in autumn. A third subgroup, comprising 40.47; of cases, was older (61.1 ± 11.0 years) and, in general, also severely affected. The incidence of this form appeared to be invariant with time. 相似文献
18.
本文对95例肾病综合征进行分析,探讨了性别、年龄、发病迁延时间、浮肿、蛋白尿、血尿、血压、尿素氮、血浆蛋白、血浆胆固醇、免疫球蛋白、补体C_3与激素反应及分型的关系。认为下列综合分析可做为判定难治性肾病综合征的参考。难治性肾病多分布在7岁以上,激素治疗4~8周血浆蛋白尚未恢复,尿镜检反复出现红细胞及颗粒管型,血清r—球蛋白不低,而补体C_3降低,提示难治性肾病。各种感染常常是造成肾病综合心难以控制,甚至死亡的重要因素。 相似文献
19.
20.
Questionnaire data may contain missing values because certain questions do not apply to all respondents. For instance, questions addressing particular attributes of a symptom, such as frequency, triggers or seasonality, are only applicable to those who have experienced the symptom, while for those who have not, responses to these items will be missing. This missing information does not fall into the category ‘missing by design’, rather the features of interest do not exist and cannot be measured regardless of survey design. Analysis of responses to such conditional items is therefore typically restricted to the subpopulation in which they apply. This article is concerned with joint multivariate modelling of responses to both unconditional and conditional items without restricting the analysis to this subpopulation. Such an approach is of interest when the distributions of both types of responses are thought to be determined by common parameters affecting the whole population. By integrating the conditional item structure into the model, inference can be based both on unconditional data from the entire population and on conditional data from subjects for whom they exist. This approach opens new possibilities for multivariate analysis of such data. We apply this approach to latent class modelling and provide an example using data on respiratory symptoms (wheeze and cough) in children. Conditional data structures such as that considered here are common in medical research settings and, although our focus is on latent class models, the approach can be applied to other multivariate models. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献