全文获取类型
收费全文 | 4499篇 |
免费 | 241篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 50篇 |
儿科学 | 162篇 |
妇产科学 | 29篇 |
基础医学 | 563篇 |
口腔科学 | 120篇 |
临床医学 | 297篇 |
内科学 | 934篇 |
皮肤病学 | 65篇 |
神经病学 | 513篇 |
特种医学 | 198篇 |
外科学 | 661篇 |
综合类 | 198篇 |
预防医学 | 222篇 |
眼科学 | 75篇 |
药学 | 331篇 |
中国医学 | 6篇 |
肿瘤学 | 326篇 |
出版年
2023年 | 34篇 |
2022年 | 51篇 |
2021年 | 125篇 |
2020年 | 51篇 |
2019年 | 91篇 |
2018年 | 116篇 |
2017年 | 85篇 |
2016年 | 86篇 |
2015年 | 108篇 |
2014年 | 155篇 |
2013年 | 206篇 |
2012年 | 289篇 |
2011年 | 310篇 |
2010年 | 163篇 |
2009年 | 169篇 |
2008年 | 236篇 |
2007年 | 242篇 |
2006年 | 263篇 |
2005年 | 217篇 |
2004年 | 203篇 |
2003年 | 196篇 |
2002年 | 153篇 |
2001年 | 120篇 |
2000年 | 103篇 |
1999年 | 94篇 |
1998年 | 64篇 |
1997年 | 57篇 |
1996年 | 54篇 |
1995年 | 29篇 |
1994年 | 50篇 |
1993年 | 40篇 |
1992年 | 61篇 |
1991年 | 56篇 |
1990年 | 41篇 |
1989年 | 40篇 |
1988年 | 41篇 |
1987年 | 51篇 |
1986年 | 41篇 |
1985年 | 39篇 |
1984年 | 29篇 |
1983年 | 26篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1980年 | 16篇 |
1979年 | 10篇 |
1978年 | 13篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 14篇 |
1967年 | 6篇 |
排序方式: 共有4750条查询结果,搜索用时 31 毫秒
991.
Pik Suan Lau Noriah Bidin Ganesan Krishnan Zaleha Nassir Hazri Bahktiar 《Journal of cosmetic and laser therapy》2015,17(2):86-89
Low-energy laser irradiance at certain wavelengths is able to stimulate the tissue bio-reaction and enhance the healing process. Collagen deposition is one of the important aspects in healing process because it can increase the strength of the skin. This study was designed to examine the biophotonic effect of irradiance on collagen production of diabetic wound in rat model. The tensile strength of skin was employed as a parameter to describe the wound. Diabetic rat models were induced by streptozotocin via intravenous injection. Skin-breaking strength was measured using an Instron tensile test machine. The experimental animals were treated with 808-nm diode laser at two different powers—0.1 and 0.5 W/cm2—and 30, 60, and 120 s for each session. The tensile strength was optimized after treated with high-power diode laser. The photostimulation effect was revealed by accelerated healing process and enhanced tensile strength of wound. Laser photostimulation on tensile strength in diabetic wound suggests that such therapy facilitates collagen production in diabetic wound healing. 相似文献
992.
B. Krishnan Pradipta Kumar Parida S. Gopalakrishnan MVS Satyparakash 《Oral and maxillofacial surgery》2013,17(4):315-317
Eruption of supernumerary teeth into the nasal cavity is a rare pathological condition. Identification of such teeth is important as they can sometimes cause significant morbidity. This report describes a young female patient with a complaint of epistaxis from the right nasal cavity. The diagnosis of a supernumerary nasal tooth was confirmed by computed tomography and the tooth was removed endoscopically with minimal morbidity. 相似文献
993.
994.
995.
D.C. Lye A. Earnest M.L. Ling T.-E. Lee H.-C. Yong D.A. Fisher P. Krishnan L.-Y. Hsu 《Clinical microbiology and infection》2012,18(5):502-508
Multidrug-resistant Gram-negative bacteria (MDR-GNB) are an emerging public health threat. Accurate estimates of their clinical impact are vital for justifying interventions directed towards preventing or managing infections caused by these pathogens. A retrospective observational cohort study was conducted between 1 January 2007 and 31 July 2009, involving subjects with healthcare-associated and nosocomial Gram-negative bacteraemia at two large Singaporean hospitals. Outcomes studied were mortality and length of stay post-onset of bacteraemia in survivors (LOS). There were 675 subjects (301 with MDR-GNB) matching study inclusion criteria. On multivariate analysis, multidrug resistance was not associated with 30-day mortality, but it was independently associated with longer LOS in survivors (coefficient, 0.34; 95% CI, 0.21–0.48; p < 0.001). The excess LOS attributable to multidrug resistance after adjustment for confounders was 6.1 days. Other independent risk factors for higher mortality included male gender, higher APACHE II score, higher Charlson comorbidity index, intensive care unit stay and presence of concomitant pneumonia. Concomitant urinary tract infection and admission to a surgical discipline were associated with lower risk of mortality. Appropriate empirical antibiotic therapy was neither associated with 30-day mortality nor LOS, although the study was not powered to assess this covariate adequately. Our study adds to existing evidence that multidrug resistance per se is not associated with higher mortality when effective antibiotics are used for definitive therapy. However, its association with longer hospitalization justifies the use of control efforts. 相似文献
996.
997.
Douglas L. Miller Zhihong Dong Chunyan Dou Krishnan Raghavendran 《Ultrasound in medicine & biology》2018,44(8):1810-1817
Pulmonary capillary hemorrhage (PCH) can be induced by diagnostic ultrasound—a potential safety issue. Anesthetized rats were intubated for intermittent positive-pressure ventilation (IPPV) with 0 end-expiratory pressure, +4?cm H2O end-expiratory pressure (PEEP) and ?4?cm H2O end-expiratory pressure (NEEP). Rats were imaged at 7.6?MHz with a Philips HDI 5000 ultrasound machine. The output was low (mechanical index [MI] = 0.22) for aiming and then was raised for 5?min in 20 different exposure groups with n = 8. Peak rarefactional pressure amplitudes were measured in water and de-rated for chest attenuation. The PCH areas were measured on the lung surface. At 2.2?MPa, PCH was 9.3 ± 6.6?mm2 for IPPV, 1.6 ± 3.2?mm2 for PEEP (p?<0.001) and 26.8 ± 6.4?mm2 for NEEP (p?<0.001). Thresholds were 1.3?MPa for IPPV, 2.1?MPa for PEEP and 1.0?MPa for NEEP. The small ventilator pressures subtracted or added to trans-capillary stress generated by diagnostic ultrasound pulses, virtually eliminating PCH for PEEP but enhancing PCH for NEEP. 相似文献
998.
Janet L. Gamble Bradford J. Hurley Peter A. Schultz Wendy S. Jaglom Nisha Krishnan Melinda Harris 《Environmental health perspectives》2013,121(1):15-22
Background: Older adults make up 13% of the U.S. population, but are projected to account for 20% by 2040. Coinciding with this demographic shift, the rate of climate change is accelerating, bringing rising temperatures; increased risk of floods, droughts, and wildfires; stronger tropical storms and hurricanes; rising sea levels; and other climate-related hazards. Older Americans are expected to be located in places that may be relatively more affected by climate change, including coastal zones and large metropolitan areas.Objective: The objective of this review is to assess the vulnerability of older Americans to climate change and to identify opportunities for adaptation.Methods: We performed an extensive literature survey and summarized key findings related to demographics; climate stressors relevant to older adults; factors contributing to exposure, sensitivity, and adaptive capacity; and adaptation strategies.Discussion: A range of physiological and socioeconomic factors make older adults especially sensitive to and/or at risk for exposure to heat waves and other extreme weather events (e.g., hurricanes, floods, droughts), poor air quality, and infectious diseases. Climate change may increase the frequency or severity of these events.Conclusions: Older Americans are likely to be especially vulnerable to stressors associated with climate change. Although a growing body of evidence reports the adverse effects of heat on the health of older adults, research gaps remain for other climate-related risks. We need additional study of the vulnerability of older adults and the interplay of vulnerability, resilience, and adaptive responses to projected climate stressors. 相似文献
999.
1000.