全文获取类型
收费全文 | 1428321篇 |
免费 | 97861篇 |
国内免费 | 2008篇 |
专业分类
耳鼻咽喉 | 18700篇 |
儿科学 | 47367篇 |
妇产科学 | 39975篇 |
基础医学 | 210516篇 |
口腔科学 | 39693篇 |
临床医学 | 130391篇 |
内科学 | 276850篇 |
皮肤病学 | 31059篇 |
神经病学 | 111796篇 |
特种医学 | 56092篇 |
外国民族医学 | 356篇 |
外科学 | 203370篇 |
综合类 | 26733篇 |
现状与发展 | 3篇 |
一般理论 | 569篇 |
预防医学 | 118533篇 |
眼科学 | 31687篇 |
药学 | 103782篇 |
8篇 | |
中国医学 | 2150篇 |
肿瘤学 | 78560篇 |
出版年
2018年 | 16830篇 |
2017年 | 14030篇 |
2016年 | 14276篇 |
2015年 | 17584篇 |
2014年 | 21951篇 |
2013年 | 30596篇 |
2012年 | 46574篇 |
2011年 | 44188篇 |
2010年 | 25027篇 |
2009年 | 25728篇 |
2008年 | 39514篇 |
2007年 | 42794篇 |
2006年 | 42643篇 |
2005年 | 49213篇 |
2004年 | 49115篇 |
2003年 | 43424篇 |
2002年 | 37871篇 |
2001年 | 59298篇 |
2000年 | 58370篇 |
1999年 | 52544篇 |
1998年 | 13828篇 |
1997年 | 12431篇 |
1996年 | 12909篇 |
1995年 | 12204篇 |
1994年 | 11389篇 |
1992年 | 43394篇 |
1991年 | 43105篇 |
1990年 | 42056篇 |
1989年 | 40616篇 |
1988年 | 37737篇 |
1987年 | 36932篇 |
1986年 | 35192篇 |
1985年 | 32877篇 |
1984年 | 24796篇 |
1983年 | 21470篇 |
1982年 | 12170篇 |
1979年 | 23990篇 |
1978年 | 17275篇 |
1977年 | 14212篇 |
1976年 | 13118篇 |
1975年 | 14819篇 |
1974年 | 18170篇 |
1973年 | 17620篇 |
1972年 | 16794篇 |
1971年 | 15841篇 |
1970年 | 14911篇 |
1969年 | 14136篇 |
1968年 | 13130篇 |
1967年 | 11899篇 |
1966年 | 11201篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
J Vargas-Barrón A Andrade-Freire J C Ramírez E Waisser J Martínez-Sánchez 《Archivos del Instituto de Cardiología de México》1989,59(2):121-124
The purpose of this study is to determine the importance of two-dimensional echocardiography performed soon after admission to the coronary care unit to provide useful information concerning wall-motion abnormalities, and to detect and characterize left ventricular thrombi. A major goal is to identify a subgroup of patients with acute myocardial infarction who are at risk for systemic embolization; in this subgroup the benefits of anticoagulation treatment would theoretically outweigh the associated risks. We studied 7 consecutive male patients, age range from 32 to 60 years, with acute myocardial infarction. Five patients had antero-septal infarction, 1 anterolateral and another had anterior wall infarction. We performed two-dimensional echocardiography within the first week after admission. All patients had severe apical-wall-motion abnormalities (akinesis or dyskinesis) and left ventricular thrombi. All patients received anticoagulation therapy. Two-dimensional echocardiography, performed one month after the first study, showed that the thrombi had decreased in size in 6 patients and could not be visualized in 1 patient. The noninvasive nature of echocardiography allows serial evaluations of patients with known left ventricular thrombi and permits assessment of the effect of therapy. 相似文献
992.
993.
S E Zhuravlev O K Galaktionov V M Efimov 《Meditsinskaia parazitologiia i parazitarnye bolezni》1989,(5):54-57
The use of multifactor statistic analysis for screening population of the northern part of the Ob river basin for helminthiasis allowed the authors to reveal a significant feedback between manifested opisthorchiasis and other types of this disease course in both sexes. The main component analysis indicates that the tentatively control group of males is presented by adolescents (14-17 years old) who are likely to be infected with Opisthorchis without evidence of its clinical manifestations. The correlation analysis demonstrated also a direct relationship between the age and manifest opisthorchiasis, as well as double mixed invasion of males (r-0.15 and 0.26, p less than 0.05 and 0.01, respectively). The first three main components explain about 55% variance in the correlation matrix of initial parameters and allow to reveal the variance source, taking into account, along with differentiation of 4 groups of opisthorchiasis patients, also the age- and sex-dependent combination of opisthorchiasis with other helminthic invasions. 相似文献
994.
Skeletal muscle blood flow and venous capacitance in patients with severe sepsis and systemic hypoperfusion 总被引:2,自引:0,他引:2
Alterations in peripheral vascular tone are presumed to contribute to circulatory failure during severe sepsis. Decreased venous tone with venous pooling may decrease effective circulatory blood volume, while decreased arterial tone with redistribution of systemic blood may compromise tissue nutrient flow. We compared forearm arterial and venous tone and forearm blood flow in ten patients with and ten patients without sepsis. The FVT, MVC, and FBF were measured by air plethysmography. In the septic patients, MCV was 1.4 +/- 0.1 ml compared with 3.1 +/- 0.2 ml in nonseptic patients (p less than 0.01). The FVT was 13.4 +/- 1.0 mm Hg/ml in septic patients versus 7.0 +/- 0.5 mm Hg/ml in nonseptic patients (p less than 0.01). The ratio of FBF to cardiac output was 0.28 +/- 0.07 percent in septic patients and 0.31 +/- 0.07 percent in nonseptic patients. These data suggest that increased peripheral venous capacitance and redistribution of skeletal muscle blood flow are not present in patients with sepsis. 相似文献
995.
The association of circulating endotoxin with the development of the adult respiratory distress syndrome 总被引:6,自引:0,他引:6
P E Parsons G S Worthen E E Moore R M Tate P M Henson 《The American review of respiratory disease》1989,140(2):294-301
Despite extensive investigation, the pathogenesis of the adult respiratory distress syndrome (ARDS) remains uncertain. As yet, there is no clear explanation of why some patients at risk for ARDS develop the syndrome, whereas others do not. Neutrophils and complement fragments have been implicated in the acute lung injury, but it is clear from published data that evidence of complement activation alone predicts neither the development nor the severity of ARDS. We investigated whether the combination of endotoxin, a leukocyte-priming agent, and complement fragments, leukocyte-stimulating agents, was associated with the development of ARDS. Ninety-eight patients were identified as being either at risk for the development of ARDS or having ARDS, and serial blood samples were obtained. There was no correlation between C5 fragments and the development of ARDS. C3 fragment levels were increased in 89% of the patients with ARDS, but they were also increased in 62% of patients at risk. Endotoxin was detected in 74% of the plasma samples obtained from patients at risk who subsequent developed ARDS and in 64% of the plasma samples obtained from the patients with ARDS. In contrast, only 22% of the plasma samples obtained from the patients at risk who did not develop ARDS had measurable endotoxin. We suggest that the combination of endotoxin and complement fragments may be one mechanism involved in the development of ARDS. 相似文献
996.
A C Meneses M A Lopes A Rocha M C Fatureto G P Lopes E R Lopes E Chapadeiro 《Arquivos de gastroenterologia》1989,26(1-2):13-16
This is a review of 4.690 necropsies and 24.209 surgical pathology specimens describing the association between megacolon chagasic and malignant tumors of the large bowel. The prevalence of malignant tumors of the large bowel was not higher in megacolon. 相似文献
997.
This study determined nursing research priorities and focused on the development of a nursing research program within a single institution. Of the 715 nurses within the Department of Nursing, 286 (40%) responded to the first round of a two-round Delphi technique, and 137 (48%) responded to the second. The following clinical priorities were determined: prevention and treatment of pressure sores, pain management, treatment of nosocomial infections, and patient education. Nonclinical priorities included staffing and its effects on turnover and patient care, job satisfaction, and factors influencing the quality of nursing care. Serendipitous findings underscored the relevance of the Department of Nursing's conceptual framework to nursing practice and research, revealed the need for dissemination of current research results, and suggested that nurses want to participate in research without assuming responsibility beyond their expertise. 相似文献
998.
999.
1000.
C4 concentrations and C4 deficiency alleles in systemic lupus erythematosus. 总被引:1,自引:0,他引:1 下载免费PDF全文
In a study of 66 patients with systemic lupus erythematosus (SLE) and 80 controls it was found that the presence of two deficiency (null) alleles of C4 had a significant effect on mean C4 concentrations in serum. In six controls who each had two C4 null alleles the mean C4 concentration in serum was 56% lower than in 43 controls without C4 null alleles; the nadir of the C4 concentration in four patients with SLE with two null alleles was also lower by a mean of 55% than in 32 patients who did not have null alleles. Reduced production of C4 allotypes in subjects with two null alleles may be an important determinant of total C4 concentration in patients with SLE. For optimal interpretation of C4 concentrations in SLE, C4 allotyping appears to be indicated, particularly to identify patients who have two null alleles of C4. 相似文献