全文获取类型
收费全文 | 5955篇 |
免费 | 658篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 51篇 |
儿科学 | 247篇 |
妇产科学 | 143篇 |
基础医学 | 904篇 |
口腔科学 | 140篇 |
临床医学 | 664篇 |
内科学 | 1016篇 |
皮肤病学 | 93篇 |
神经病学 | 461篇 |
特种医学 | 314篇 |
外科学 | 890篇 |
综合类 | 143篇 |
一般理论 | 2篇 |
预防医学 | 556篇 |
眼科学 | 97篇 |
药学 | 467篇 |
中国医学 | 5篇 |
肿瘤学 | 452篇 |
出版年
2021年 | 64篇 |
2020年 | 49篇 |
2019年 | 65篇 |
2018年 | 113篇 |
2017年 | 100篇 |
2016年 | 104篇 |
2015年 | 140篇 |
2014年 | 183篇 |
2013年 | 251篇 |
2012年 | 272篇 |
2011年 | 220篇 |
2010年 | 191篇 |
2009年 | 180篇 |
2008年 | 186篇 |
2007年 | 239篇 |
2006年 | 227篇 |
2005年 | 197篇 |
2004年 | 193篇 |
2003年 | 173篇 |
2002年 | 165篇 |
2001年 | 188篇 |
2000年 | 176篇 |
1999年 | 140篇 |
1998年 | 162篇 |
1997年 | 149篇 |
1996年 | 170篇 |
1995年 | 113篇 |
1994年 | 123篇 |
1993年 | 93篇 |
1992年 | 153篇 |
1991年 | 142篇 |
1990年 | 123篇 |
1989年 | 155篇 |
1988年 | 141篇 |
1987年 | 117篇 |
1986年 | 94篇 |
1985年 | 100篇 |
1984年 | 78篇 |
1983年 | 49篇 |
1982年 | 53篇 |
1981年 | 44篇 |
1980年 | 49篇 |
1979年 | 52篇 |
1978年 | 56篇 |
1977年 | 50篇 |
1976年 | 39篇 |
1975年 | 51篇 |
1974年 | 40篇 |
1973年 | 37篇 |
1971年 | 38篇 |
排序方式: 共有6645条查询结果,搜索用时 31 毫秒
91.
Marie T. Williams D.W. Parsons Elizabeth R. Ellis A.J. Martin S.E. Giles R.A. Frick 《Physiotherapy theory and practice》2013,29(2):57-67
Cystic fibrosis (CF) results in increased energy requirements at rest. However, the energy expended during physiotherapy management is unknown. The aim of this study, therefore, is to examine the energy expended during two commonly used forms of chest physiotherapy in CF subjects. Twenty-six CF subjects completed a randomised crossover trial with 48 hours between treatments. Two regimens of treatment were conducted: therapist-assisted treatment (active cycle of breathing, ACBT, with percussion, vibration), and independent treatment (ACBT alone, under the supervision of a physiotherapist). Subjects completed pulmonary function tests before and after either treatment. Indirect calorimetry and oximetry parameters were recorded at rest, during, and following treatment. Treatment groups were compared using ANOVA and two-sample crossover t-tests. When compared to resting values, physiotherapy treatment resulted in significant increases in VO2, VCO2 and respiratory exchange ratio. No difference was evident between treatment regimens for the change in VO2 between baseline and treatment. The increase in ventilation (baseline to treatment) was significantly greater for the therapist-assisted treatment. The therapist-assisted ACBT was associated with a significant carryover effect for forced expiratory flow at 50% of vital capacity (FEF50). Oxygen requirements for the two treatments were similar. However, the assisted regimen resulted in greater changes in minute ventilation during treatment and improved 48-hour post-treatment pulmonary function after only one treatment session. These findings suggest that the inclusion of percussion and vibration within the ACBT may influence respiratory muscle activity during treatment and result in improved pulmonary function. 相似文献
92.
93.
In order to study the pattern of B cell involvement in acute nonlymphocytic leukemia (ANLL), multiple B lymphoid cell lines were established by Epstein-Barr virus transformation of peripheral blood mononuclear cells from two patients with the disease who were heterozygous for the X chromosome-linked glucose-6-phosphate dehydrogenase (G6PD). In one patient, the progenitor cells involved by the leukemia exhibited multipotent differentiative expression, whereas in the other patient the cells showed differentiative expression restricted to the granulocytic pathway. In the patient whose abnormal clone showed multipotent expression, the ratio of B-A G6PD in B lymphoid cell lines was skewed in the direction of type B (the enzyme characteristic of the leukemia clone) and significantly different from the 1:1 ratio expected. It is, therefore, likely that the neoplastic event occurred in a stem cell common to the lymphoid series as well as to the myeloid series. In contrast, evidence for B cell involvement was not detected in the patient whose ANLL progenitor cells exhibited restricted differentiative expression. These findings underscore the heterogeneity of ANLL. Clinically and morphologically similar malignancies in these two patients originated in progenitors with different patterns of stem cell differentiative expression. This difference may reflect differences in cause and pathogenesis. 相似文献
94.
CGA-7 and HHF, two monoclonal antibodies that recognize muscle actin and react with adherent cells in human long-term bone marrow cultures 总被引:4,自引:0,他引:4
The CGA-7, a monoclonal antibody that reacts with smooth muscle cell actin but not with endothelial cell or fibroblast actin, and HHF, a monoclonal antibody that reacts with smooth muscle, skeletal muscle, and cardiac muscle actin, both recognize microfilaments present within adherent cells from actively hematopoietic human long-term marrow cultures. Macrophages, monocytes, and cultured marrow fibroblasts do not react with either antibody. These data suggest that the anti-actin antibodies may serve as useful markers for in vitro microenvironmental cells and lend support to the hypothesis that stromal cells from long- term marrow cultures are different from marrow fibroblasts and may constitute a unique cell lineage. 相似文献
95.
96.
97.
Gillinov AM Casselman FP Lytle BW Blackstone EH Parsons EM Loop FD Cosgrove DM 《The Annals of thoracic surgery》1999,67(2):382-386
BACKGROUND: The purpose of this study was to determine the prevalence, outcome, and operative strategies for patients having injury to a patent left internal thoracic artery (LITA) graft to the left anterior descending coronary artery (LAD) at coronary reoperation. METHODS: Of 655 patients with a patent LITA graft to the LAD undergoing coronary reoperation from 1986 to 1997, 35 (5.3%) sustained intraoperative injury to the LITA graft. RESULTS: Strategies to restore flow to the LAD included new saphenous vein graft to the LAD in 15 patients, saphenous vein graft to the LITA stump in 7, saphenous vein graft to the LAD and repair of the LITA graft in 6, and other strategies in 7. All or part of the LITA graft to the LAD was salvaged in 20 patients (57%). Fourteen patients (40%) sustained perioperative myocardial infarction, and 3 patients died (8.6%). The 3 patients who died all had stenosis or thrombosis of the graft to the LAD documented at autopsy. CONCLUSIONS: We conclude that (1) the prevalence of injury to a patent LITA graft is 5.3%; (2) a variety of techniques can be used to restore blood flow to the LAD; and (3) ineffective revascularization of the LAD in this situation is associated with operative mortality. At primary coronary artery bypass grafting, the LITA pedicle should be positioned in the left chest away from the posterior sternal table; this strategy may minimize the risk of LITA graft injury at coronary reoperation. 相似文献
98.
The historical origins of interstitial cystitis 总被引:2,自引:0,他引:2
99.
A review of the use of lymphography at this hospital, a major oncology centre, is presented. The advent of computed tomography has brought a dramatic reduction in the number of lymphograms currently performed for diseases such as lymphoma, testicular tumours and gynaecological malignancies. This study analyses the reasons for this decline, and concludes that valuable information can still be obtained from lymphography in certain selected groups of patients. 相似文献
100.
Roberto L. Muller Leah Gerber Daniel M. Moreira Gerald Andriole Jr. Robert J. Hamilton Neil Fleshner J. Kellogg Parsons Stephen J. Freedland 《European urology》2013