全文获取类型
收费全文 | 3866146篇 |
免费 | 305292篇 |
国内免费 | 15697篇 |
专业分类
耳鼻咽喉 | 52185篇 |
儿科学 | 120542篇 |
妇产科学 | 98892篇 |
基础医学 | 604844篇 |
口腔科学 | 104452篇 |
临床医学 | 348335篇 |
内科学 | 688628篇 |
皮肤病学 | 101369篇 |
神经病学 | 323764篇 |
特种医学 | 151844篇 |
外国民族医学 | 262篇 |
外科学 | 591517篇 |
综合类 | 114268篇 |
现状与发展 | 26篇 |
一般理论 | 2374篇 |
预防医学 | 315451篇 |
眼科学 | 91411篇 |
药学 | 269644篇 |
26篇 | |
中国医学 | 12712篇 |
肿瘤学 | 194589篇 |
出版年
2021年 | 58830篇 |
2020年 | 36852篇 |
2019年 | 60364篇 |
2018年 | 75060篇 |
2017年 | 57307篇 |
2016年 | 64132篇 |
2015年 | 79133篇 |
2014年 | 113802篇 |
2013年 | 179808篇 |
2012年 | 113611篇 |
2011年 | 115252篇 |
2010年 | 125203篇 |
2009年 | 127327篇 |
2008年 | 98966篇 |
2007年 | 103315篇 |
2006年 | 112116篇 |
2005年 | 106511篇 |
2004年 | 107402篇 |
2003年 | 96793篇 |
2002年 | 85736篇 |
2001年 | 136970篇 |
2000年 | 130378篇 |
1999年 | 122652篇 |
1998年 | 68948篇 |
1997年 | 65501篇 |
1996年 | 63176篇 |
1995年 | 58676篇 |
1994年 | 52667篇 |
1993年 | 48996篇 |
1992年 | 85312篇 |
1991年 | 81221篇 |
1990年 | 76928篇 |
1989年 | 75315篇 |
1988年 | 69211篇 |
1987年 | 67394篇 |
1986年 | 63651篇 |
1985年 | 62906篇 |
1984年 | 54954篇 |
1983年 | 49631篇 |
1982年 | 43660篇 |
1981年 | 41036篇 |
1980年 | 38491篇 |
1979年 | 44949篇 |
1978年 | 38311篇 |
1977年 | 34970篇 |
1976年 | 32013篇 |
1975年 | 30832篇 |
1974年 | 32528篇 |
1973年 | 31218篇 |
1972年 | 29076篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
To examine the prevalence of Internet sex networking among men who have sex with men (MSM) in Hong Kong and risk behaviors associated with the behavior, a telephone survey of 15,230 Hong Kong Chinese men aged 18-60 was conducted. Of the 283 active MSM (having engaged in some MSM behaviors in the last 6 months) identified, 17.7% had networked for MSM partners via the Internet in the last 6 months. Younger age (odds ratio [OR] for age < or = 25 vs. age >25 = 4.67, 95% confidence interval [CI] = 2.35-9.28) and being an anal-sex MSM (OR = 4.72, 95% CI=2.36-9.44) were independent predictors of Internet sex networking. Being an Internet sex networker was associated with some risk behaviors such as having contracted a sexually transmitted disease (adjusted OR = 4.79, 95% CI = 1.34-17.11), having had > or = 3 MSM partners (adjusted OR = 4.74, 95% CI = 2.20-10.23), and having engaged in anal sex (adjusted OR = 3.95, 95% CI = 1.89-8.23). HIV prevention programs for MSM should thereby include Internet-based interventions. 相似文献
992.
Eun Sang Park Jung Im Na Seon Ok Kim Chang Hun Huh Sang Woong Youn Kyoung Chan Park 《Skin research and technology》2006,12(4):298-302
Background/purpose: Vitiligo and nevus depigmentosus (ND) present similar hypopigmented macules with significantly different prognoses. Although the distinction between the two diseases is important, differential diagnosis relies on medical history and physical examination, which is far from decisive in some cases. The Mexameter® is an objective skin color-measuring device, and has been reported to provide a reproducible and sensitive means of quantifying small skin color differences. In this study, we investigated the usefulness of a Mexameter® for discriminating these diseases.
Methods: A selection of 202 hypopigmented skin lesions (182 from vitiligo and 20 from ND) were the objects of this study. Using a Mexameter, MIs were obtained from lesions and symmetrically located control skin. RMIs, ratios of the MIs of lesional skins to control skins, were calculated.
Results: The mean MIs and RMIs were significantly different for vitiligo and ND. The mean RMI of ND lesions was 74±13, which was significantly higher than that of vitiligo lesions (50±24). No ND lesion had an RMI of <50%.
Conclusion: This study shows that the Mexameter® , an objective pigment-measuring device, can be used to achieve a more accurate diagnosis of hypopigmentary disorders, and that the relative melanin index (RMI), which represents the relative pigment levels, might be a more effective parameter than the melanin index (MI) itself for comparing pigmentation differences. 相似文献
Methods: A selection of 202 hypopigmented skin lesions (182 from vitiligo and 20 from ND) were the objects of this study. Using a Mexameter, MIs were obtained from lesions and symmetrically located control skin. RMIs, ratios of the MIs of lesional skins to control skins, were calculated.
Results: The mean MIs and RMIs were significantly different for vitiligo and ND. The mean RMI of ND lesions was 74±13, which was significantly higher than that of vitiligo lesions (50±24). No ND lesion had an RMI of <50%.
Conclusion: This study shows that the Mexameter
993.
S Chinn S H Downs J M Anto M W Gerbase B Leynaert R de Marco C Janson D Jarvis N Künzli J Sunyer C Svanes E Zemp U Ackermann-Liebrich P Burney 《The European respiratory journal》2006,28(4):763-771
The incidence of asthma has been reported to be associated with obesity. An alternative analysis, of net change in prevalence, does not require exclusion of those with asthma at baseline. Follow-up data were obtained from 9,552 participants in the European Community Respiratory Health Survey and the Swiss cohort Study on Air Pollution and Lung Disease in Adults. Incidence of asthma was analysed by proportional hazards regression, and net changes in symptoms and asthma status by generalised estimating equations, by obesity group. Incidence and net change in ever having had asthma were greater in females than in males, and in participants who remained obese compared with those who were never obese (hazard ratio 2.00, 95% confidence interval 1.25-3.20; excess net change 2.8%, 0.4-5.3% per 10 yrs). The effect of being obese on net change in diagnosed asthma was greater in females than in males, but for net change in wheeze without a cold it was greater in males. The present results are consistent with asthma being more frequently diagnosed in females, especially obese females. These findings may help to explain the reports of a stronger association between asthma and obesity in females than in males. 相似文献
994.
Abstract – The aim of this study was to investigate mechano-sensory responses of injured and uninjured incisor teeth. Twenty-five children who had experienced dental trauma, together with age- and gender-matched controls, were studied prospectively. Touch thresholds of incisor teeth from both groups were determined using calibrated sets of von Frey hairs (force range 0.5–10.0 g in 0.5 g increments) using a forced choice staircase method. Forces were applied perpendicular to the buccal enamel surfaces along the midline, 2 mm from the incisal edge. Touch threshold was defined as the lowest force detected in three out of the five occasions. Following statistical analysis, P < 0.05 was considered significant. At initial examination, the touch threshold values of 25 traumatised teeth were significantly greater than the untraumatised controls ( P < 0.001), and these values approached those of the control teeth over 3–12 months ( P > 0.05). Dental trauma was associated with increased touch thresholds in permanent incisor teeth, with recovery toward healthy control values usually occurring between 3–12 months. 相似文献
995.
996.
997.
998.
本文报告了暗纹节菱孢[Arthinium phaeospemum(Corda)Ellis]所致皮肤真菌病的组织病理学及超微结构观察。HE、PAS、镀银染色(Szatri)法及铅铀染色,对皮损的组织病理改变,进行了光镜及透射电镜观察。光镜下发现暗纹节菱孢引起真皮及皮下脂肪组织广泛性病理浸润,由多种细胞构成的肉芽肿,尤其对皮肤附属器严重破坏。在病理浸润中可见球形、卵圆形、菱形及晶体形,玫瑰红色、棕色及褐色孢子。透射电镜下见真皮成纤维细胞胞浆内吞噬多数界线清楚的圆形小体,空泡内也有相同的小体,胞浆空泡甚多,胞核完整。同时见到破坏的溶酶体。病理浸润内形态各异的孢子及不同颜色,是孢子生长的不同阶段。 相似文献
999.
Esophageal foreign body causing direct aortic injury. 总被引:4,自引:0,他引:4
Foreign bodies in the esophagus are uncommon causes of esophageal perforation. Many nonperforating cases are successfully managed by flexible gastroscopy. However, complicated foreign bodies such as those that result in esophageal perforation and vascular injury are best managed surgically. Gastroscopy remains the primary method of diagnosis. A case of a 59-year-old woman who developed retrosternal and intrascapular pain, odynophagia and hematemesis after eating fish is reported. Flexible gastroscopy showed arterial bleeding from the midthoracic esophagus. Computed tomography scan localized a 3 cm fish bone perforating the esophagus with surrounding hematoma. An aortogram did not reveal an actively bleeding aortoesophageal fistula. The fish bone was surgically removed and the patient recovered with no postoperative complications. This case illustrates the importance of early consideration for surgical intervention when confronted with a brisk arterial bleed from the esophagus with suggestive history of foreign body ingestion. 相似文献
1000.
This review discusses treatment options for men with premature ejaculation (PE), a common sexual dysfunction characterized
by short ejaculatory latency, decreased sexual satisfaction, and distress. For a number of reasons, including embarrassment
and the belief that PE is a normal part of aging, that it has no effective treatment, or that it will resolve itself, few
men with PE seek treatment. Although several treatment options exist (eg, behavioral, cognitive, and sex therapy methods;
desensitizing drugs; off-label use of antidepressants, phosphodiesterase type 5 inhibitors, or à-blockers), the majority of
men with PE are not satisfied with their results. New pharmacologic drugs develped specifically for the treatment of PE are
undergoing evaluation in clinical trials. For example, recent clinical research studies have revealed on-demand administration
of one such drug, dapoxetine, which achieved significant improvements in ejaculatory latency, control over ejaculation, and
satisfaction with sexual intercourse. In addition, partners of men who received dapoxetine likewise reported improved satisfaction
with sexual intercourse. Future studies may reveal that integration of pharmacologic drugs with psychologic and/or behavioral
therapy techniques may be the optimal approach to the management of PE. PE is a treatable condition, and new drugs in development
may provide benefits over those available. 相似文献