全文获取类型
收费全文 | 18618篇 |
免费 | 1279篇 |
国内免费 | 616篇 |
专业分类
耳鼻咽喉 | 134篇 |
儿科学 | 430篇 |
妇产科学 | 178篇 |
基础医学 | 1976篇 |
口腔科学 | 290篇 |
临床医学 | 2323篇 |
内科学 | 2710篇 |
皮肤病学 | 224篇 |
神经病学 | 1029篇 |
特种医学 | 1349篇 |
外国民族医学 | 1篇 |
外科学 | 1823篇 |
综合类 | 2451篇 |
现状与发展 | 4篇 |
预防医学 | 936篇 |
眼科学 | 276篇 |
药学 | 3080篇 |
5篇 | |
中国医学 | 733篇 |
肿瘤学 | 561篇 |
出版年
2024年 | 23篇 |
2023年 | 219篇 |
2022年 | 392篇 |
2021年 | 666篇 |
2020年 | 520篇 |
2019年 | 472篇 |
2018年 | 545篇 |
2017年 | 500篇 |
2016年 | 535篇 |
2015年 | 609篇 |
2014年 | 1231篇 |
2013年 | 1348篇 |
2012年 | 1180篇 |
2011年 | 1333篇 |
2010年 | 1056篇 |
2009年 | 1011篇 |
2008年 | 1093篇 |
2007年 | 942篇 |
2006年 | 809篇 |
2005年 | 763篇 |
2004年 | 607篇 |
2003年 | 578篇 |
2002年 | 494篇 |
2001年 | 348篇 |
2000年 | 332篇 |
1999年 | 299篇 |
1998年 | 267篇 |
1997年 | 250篇 |
1996年 | 241篇 |
1995年 | 256篇 |
1994年 | 195篇 |
1993年 | 179篇 |
1992年 | 135篇 |
1991年 | 142篇 |
1990年 | 91篇 |
1989年 | 81篇 |
1988年 | 100篇 |
1987年 | 68篇 |
1986年 | 69篇 |
1985年 | 82篇 |
1984年 | 77篇 |
1983年 | 49篇 |
1982年 | 55篇 |
1981年 | 57篇 |
1980年 | 50篇 |
1979年 | 36篇 |
1978年 | 36篇 |
1977年 | 22篇 |
1976年 | 16篇 |
1971年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
71.
本文针对目前医疗氧舱自动化程度不高,各种治疗参数难以定量控制的特点,设计出了以微型计算机为控制核心的医疗氧舱自动供排气系统,并重点介绍了微型计算机的硬件和软件设计。 相似文献
72.
目的:观察高压氧结合针灸治疗脑外伤患者的疗效。方法:对96例脑外伤患者采用高压氧、针灸配合药物进行综合治疗。同时,对83例对照组患者根据病情给予降颅压、抗感染、改善脑供血、保护脑细胞等治疗,有手术指征者行清除血肿、减压和清创术。结果:出院时两组患者功能比较,治疗组明显优于对照组,有显著性差异(P<0.O1),疗效治疗组也明显好于对照组。结论:高压氧结合针灸治疗能够明显提高脑损伤患者疗效,对肢体功能有明显提高。 相似文献
73.
T. KRANTZ F. SZTUK F. SWIATEK J. JACOBSEN N. H. SECHER 《Acta anaesthesiologica Scandinavica》1997,41(6):719-724
Background: We evaluated the ability of the standards issued by the Danish Society of Anaesthesiologists to reflect a blood loss.
Methods: In 9 pigs bled (0–24 ml kg-1 ) and retransfused (to 28 ml kg-1 ) during halothane anaesthesia, central cardiovascular, thoracic electrical impedance (TI), oxygen, acid-base and temperature variables were recorded.
Results: With the recommendation for minor surgery (mean arterial pressure (MAP) and heart rate (HR)), the correlation to the blood loss was 0.74 ( P < 0.001) and with that for major surgery (MAP, HR, central venous pressure (CVP) and rectal temperature (Tempr )) it was 0.79 ( P < 0.001). With the recommendation for extensive surgery (MAP, HR, CVP, pulmonary artery catheter variables and the central-peripheral temperature difference (ΔTempr-t )), the correlation was 0.84 ( P < 0.001). Non-invasive monitoring (MAP, HR, ΔTempr-t TI and near-infrared spectroscopy of the brain (Sinvos O2 )) was only slightly better than basal monitoring (r=0.76, P < 0.001). However, adding arterial base excess (BE), TI and peripheral temperature (Tempt ) to the recommendation for major surgery resulted in a correlation of 0.87 ( P < 0.001), while adding BE and TI to the recommendation for extensive surgery raised correlation to only 0.88 ( P < 0.001).
Conclusion: When the recommendations were followed the correlation to the blood loss ranged from 0.74–0.84. However, with the recording of MAP, HR, CVP, ΔTempr-t, BE and TI a correlation of 0.87 was achieved, indicating that a pulmonary artery catheter may not be in need for patients undergoing surgical procedures with expected haemorrhage. 相似文献
Methods: In 9 pigs bled (0–24 ml kg
Results: With the recommendation for minor surgery (mean arterial pressure (MAP) and heart rate (HR)), the correlation to the blood loss was 0.74 ( P < 0.001) and with that for major surgery (MAP, HR, central venous pressure (CVP) and rectal temperature (Temp
Conclusion: When the recommendations were followed the correlation to the blood loss ranged from 0.74–0.84. However, with the recording of MAP, HR, CVP, ΔTemp
74.
75.
Improvement of oxygen metabolic reserve after extracranial-intracranial bypass surgery in patients with severe haemodynamic insufficiency 总被引:8,自引:0,他引:8
Summary The effectiveness of extracranial-intracranial arterial bypass (EC-IC bypass) surgery on impaired haemodynamic status was studied in 12 patients with reduced regional cerebral perfusion pressure (rCPP) and elevated regional oxygen extraction fraction (rOEF) in the area distal to the symptomatic arterial lesion. Postoperative positron emission tomography (PET) study demonstrated a statistically significant decrease of rOEF in the operated hemispheres with disappearance of the pre-operative interhemispheric rOEF difference. Regional cerebral blood flow (rCBF) and regional cerebral oxygen metabolism (rCMRO2) were also increased in the operated hemispheres with disappearance of the pre-operative interhemispheric differences. Regional CBF/regional cerebral blood volume (rCBV) ratios of the symptomatic hemispheres were increased after surgery, but were still lower than in the contralateral hemispheres. We conclude that EC-IC bypass surgery improves impaired cerebral oxygen metabolic reserve. 相似文献
76.
Ruptured sinus of Valsalva aneurysms are rare. We report a case in which the usual clinical manifestations were not present and the patient was initially treated as an acute pulmonary embolus. Despite three negative echocardiograms an intra-cardiac shunt was suspected because of a persistently elevated mixed venous oxygen saturation. Cardiac catheterisation confirmed the diagnosis. Surgical repair was performed and post operative recovery was uneventful. 相似文献
77.
Objective: To investigate whether pentoxifylline could play a role in attenuation of the hazardous effects of ischemia/reperfusion on corporeal tissue in a rat model of veno-occlusive priapism (VOP).
Materials and methods: Placebo and pentoxifylline were given to eight groups of rats prior to priapism being induced by a vacuum constrictive device for durations of 6 and 12 h, respectively. Half of the groups of rats that underwent the same duration of priapism (ischemic) were subjected to 1 h of detumescence after band removal (reperfusion). One group underwent no manipulation and no drug administration and served as a baseline determination (control). Corporeal homogenates were examined for lipid peroxidation (LP) derived malondialdehyde (MDA) accumulation via thiobarbituric acid assay.
Results: MDA concentration differed significantly between VOP rats and controls (P < 0.001) but did not differ significantly between ischemic-only groups and reperfused groups (P > 0.05). In the pentoxifyllinepretreated groups, although MDA accumulation tended to be slightly lower than in the placebo groups, the difference was not statistically significant (P > 0.05) either in the 6- or 12-h duration priapic groups.
Conclusions: LP, an indicator of radical oxygen metabolite (ROM) induced injury, occurs in rat corporeal tissue during and after abolishment of VOP. Single-dose pentoxifylline pretreatment failed to exert a protective effect on corporeal tissue in a rat model of VOP in terms of attenuation of LP. 相似文献
78.
79.
Active oxygen species generated by monocytes and polymorphonuclear cells in Crohn's disease 总被引:4,自引:0,他引:4
Tetsuji Kitahora MD Koichi Suzuki MD Hitoshi Asakura MD Takeshi Yoshida MD Makoto Suematsu MD Mamoru Watanabe MD Sadakazu Aiso MD Dr. Masaharu Tsuchiya MD 《Digestive diseases and sciences》1988,33(8):951-955
Chemiluminescence (CL) analysis of monocytes and polymorphonuclear cells (PMNs) was performed on 13 patients with Crohn's disease (CD) and 10 healthy volunteers. The percentages of monocyte populations in mononuclear cells obtained from the patients with CD were greater than those from the healthy volunteers, but the numbers of PMNs were not different between the two groups. The peak level of phorbol myristate acetate (PMA)-induced CL activity generated by diluted whole blood from the patients with CD was more significantly elevated than that from the healthy volunteers, whereas the peak levels of opsonized zymosan-induced CL activity did not differ between the two groups. In monocytes, the peak levels of both PMA- and opsonized zymosan-induced CL activity were significantly higher in the patients with CD than in the healthy volunteers. CL in PMNs, however, showed no significant difference between CD and controls. It is suggested that monocytes of CD have a large capacity to generate active oxygen species. The present study suggests that excessive active oxygen species released by monocytes and perhaps macrophages may play an important role in formation of the intestinal lesions in CD.This work was supported by the Grant of Tokuteishitsukan from the Japanese Ministry of Welfare and Health. 相似文献
80.
T. Yoshimaru Y. Suzuki T. Matsui† K. Yamashita† T. Ochiai‡ M. Yamaki† K. Shimizu 《Clinical and experimental allergy》2002,32(4):612-618
BACKGROUND: Previous studies have shown that rat peritoneal mast cells and mast cell model rat basophilic leukaemia (RBL-2H3) cells generate intracellular reactive oxygen species (ROS) in response to antigen challenge. However, the physiological significance of the burst of ROS is poorly understood. OBJECTIVE: The present study was undertaken to investigate the role of superoxide anion in mediator release in rat and human cell systems. METHODS: RBL-2H3 cells were directly stimulated with anti-rat FcepsilonRI alpha-subunit monoclonal antibody (mAb). For the analysis of human cell system, leucocytes were isolated by dextran sedimentation from healthy volunteers or from patients, and challenged either with anti-human FcepsilonRI mAb or with the relevant antigens. Superoxide generation was determined by chemiluminescence-based methods. The releases of histamine and leukotrienes (LT)s were determined by enzyme-linked immunosorben assay (ELISA). RESULTS: Cross-linking of FcepsilonRI on RBL-2H3 cells or on human leucocytes from healthy donors by the anti-FcepsilonRI mAb resulted in a rapid generation of superoxide anion, as determined by chemiluminescence using superoxide-specific probes. Similarly, leucocytes from patients generated superoxide anion in response to the challenge with the relevant allergen but not with the irrelevant allergen. Furthermore, diphenyleneiodonium (DPI), a well-known inhibitor of flavoenzymes suppressed the superoxide generation and the release of histamine and LTC4 induced by the anti-FcepsilonRI mAb or by allergen in parallel. CONCLUSION: These results indicate that both RBL-2H3 cells and human basophils generate superoxide anion upon FcepsilonRI cross-linking either by antibody or by allergen challenge and that blockade of the generation prevents the release of allergic mediators. The findings strongly support the role of superoxide generation in the activation of mast cells and basophils under both physiological and pathological conditions. The findings suggest that drugs regulating the superoxide generation have potential therapeutic use for allergic disorders. 相似文献