全文获取类型
收费全文 | 400281篇 |
免费 | 28549篇 |
国内免费 | 2297篇 |
专业分类
耳鼻咽喉 | 4949篇 |
儿科学 | 9359篇 |
妇产科学 | 8237篇 |
基础医学 | 55311篇 |
口腔科学 | 7794篇 |
临床医学 | 39334篇 |
内科学 | 81041篇 |
皮肤病学 | 7588篇 |
神经病学 | 35451篇 |
特种医学 | 16082篇 |
外国民族医学 | 11篇 |
外科学 | 59030篇 |
综合类 | 5487篇 |
现状与发展 | 5篇 |
一般理论 | 395篇 |
预防医学 | 29973篇 |
眼科学 | 10552篇 |
药学 | 30049篇 |
4篇 | |
中国医学 | 1935篇 |
肿瘤学 | 28540篇 |
出版年
2023年 | 1919篇 |
2022年 | 1507篇 |
2021年 | 9726篇 |
2020年 | 5595篇 |
2019年 | 8691篇 |
2018年 | 10173篇 |
2017年 | 7562篇 |
2016年 | 8960篇 |
2015年 | 11268篇 |
2014年 | 15220篇 |
2013年 | 19846篇 |
2012年 | 30063篇 |
2011年 | 30596篇 |
2010年 | 17499篇 |
2009年 | 15237篇 |
2008年 | 25411篇 |
2007年 | 26110篇 |
2006年 | 25227篇 |
2005年 | 24798篇 |
2004年 | 22882篇 |
2003年 | 20857篇 |
2002年 | 19124篇 |
2001年 | 6437篇 |
2000年 | 5603篇 |
1999年 | 5548篇 |
1998年 | 4323篇 |
1997年 | 3454篇 |
1996年 | 2596篇 |
1995年 | 2863篇 |
1994年 | 2423篇 |
1993年 | 2130篇 |
1992年 | 2774篇 |
1991年 | 2700篇 |
1990年 | 2317篇 |
1989年 | 2179篇 |
1988年 | 2076篇 |
1987年 | 1951篇 |
1986年 | 1921篇 |
1985年 | 1822篇 |
1984年 | 1824篇 |
1983年 | 1647篇 |
1982年 | 1701篇 |
1981年 | 1653篇 |
1980年 | 1447篇 |
1979年 | 1200篇 |
1978年 | 1132篇 |
1977年 | 999篇 |
1976年 | 904篇 |
1975年 | 753篇 |
1974年 | 822篇 |
排序方式: 共有10000条查询结果,搜索用时 703 毫秒
41.
42.
43.
Ho-Chul Jung Sung-Bin Chon Won Sup Oh Dong-Hyun Lee Ho-Jin Lee 《The American journal of tropical medicine and hygiene》2015,92(2):256-261
Scrub typhus usually presents as acute undifferentiated fever. This cross-sectional study included adult patients presenting with acute undifferentiated fever defined as any febrile illness for ≤ 14 days without evidence of localized infection. Scrub typhus cases were defined by an antibody titer of a ≥ fourfold increase in paired sera, a ≥ 1:160 in a single serum using indirect immunofluorescence assay, or a positive result of the immunochromatographic test. Multiple regression analysis identified predictors associated with scrub typhus to develop a prediction rule. Of 250 cases with known etiology of acute undifferentiated fever, influenza (28.0%), hepatitis A (25.2%), and scrub typhus (16.4%) were major causes. A prediction rule for identifying suspected cases of scrub typhus consisted of age ≥ 65 years (two points), recent fieldwork/outdoor activities (one point), onset of illness during an outbreak period (two points), myalgia (one point), and eschar (two points). The c statistic was 0.977 (95% confidence interval = 0.960–0.994). At a cutoff value ≥ 4, the sensitivity and specificity were 92.7% (79.0–98.1%) and 90.9% (86.0–94.3%), respectively. Scrub typhus, the third leading cause of acute undifferentiated fever in our region, can be identified early using the prediction rule. 相似文献
44.
Krishna Pillai Javid Akhter Terence C. Chua Mena Shehata Nayef Alzahrani Issan Al-Alem David L. Morris 《Medicine》2015,94(9)
Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices.With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored.With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres.Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected.Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5.MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink. 相似文献
45.
The Pedagogical Challenges of Teaching High School Bioethics: Insights from the Exploring Bioethics Curriculum 下载免费PDF全文
Mildred Z. Solomon David Vannier Jeanne Ting Chowning Jacqueline S. Miller Katherine F. Paget 《The Hastings Center report》2016,46(1):11-18
A belief that high school students have the cognitive ability to analyze and assess moral choices and should be encouraged to do so but have rarely been helped to do so was the motivation for developing Exploring Bioethics, a six‐module curriculum and teacher guide for grades nine through twelve on ethical issues in the life sciences. A multidisciplinary team of bioethicists, science educators, curriculum designers, scientists, and high school biology teachers worked together on the curriculum under a contract between the National Institutes of Health and Education Development Center, a nonprofit research and development organization with a long history of innovation in science education. At the NIH, the Department of Bioethics within the Clinical Center and the Office of Science Education within the Office of the Director guided the project.Our overarching goal for Exploring Bioethics was to introduce students to bioethics as a field of inquiry and to enable them to develop ethical reasoning skills so they could move beyond “gut reactions” to more nuanced positions. 相似文献
46.
47.
48.
Kun‐Yong Sung Seungkoo Lee Yeonjin Jeong Sang‐Yeul Lee 《The Australasian journal of dermatology》2021,62(1):60-63
A classic pilomatricoma, which usually presents with an asymptomatic, solitary, firm, subcutaneous nodule in the head, neck, or extremities of the paediatric population, is easily diagnosed based on its characteristic clinical and histopathological features. However, its variants often pose particular diagnostic challenges to clinicians due to their rarity and diverse clinicopathological features. We present a new pseudocystic variant, manifesting as solid lesions floating in a fluid‐filled sac. 相似文献
49.
The present narrative review examines the scientific evidence of the biological mechanisms that may link periodontitis and diabetes, as a source of comorbidity. Publications regarding periodontitis and diabetes, in human, animals, and in vitro were screened for their relevance. Periodontal microbiome studies indicate a possible association between altered glucose metabolism in prediabetes and diabetes and changes in the periodontal microbiome. Coinciding with this, hyperglycemia enhances expression of pathogen receptors, which enhance host response to the dysbiotic microbiome. Hyperglycemia also promotes pro-inflammatory response independently or via the advanced glycation end product/receptor for advanced glycation end product pathway. These processes excite cellular tissue destruction functions, which further enhance pro-inflammatory cytokines expression and alteration in the RANKL/osteoprotegerin ratio, promoting formation and activation of osteoclasts. The evidence supports the role of several pathogenic mechanisms in the path of true causal comorbidity between poorly controlled diabetes and periodontitis. However, further research is needed to better understand these mechanisms and to explore other mechanisms. 相似文献
50.
Hyo-Kon Kim Sung-Han Ha Gi-Jun Lee Sun-O Yu Jung-Rae Kim 《Clinics in Orthopedic Surgery》2015,7(3):414-417
Synovial chondromatosis is a rare lesion in the wrist, but some cases in the distal radioulnar joint have been reported and previous case reports emphasize joint calcifications, shown on preoperative plain radiographs. We report an extremely uncommon case of synovial chondromatosis in the pisotriquetral joint, in which radiographs and magnetic resonance imaging did not demonstrate apparent calcified bodies. In our case, for the accurate diagnosis and treatment, surgical exploration of the joint and synovectomy with removal of loose bodies was performed. 相似文献