全文获取类型
收费全文 | 42175篇 |
免费 | 1477篇 |
国内免费 | 219篇 |
专业分类
耳鼻咽喉 | 323篇 |
儿科学 | 952篇 |
妇产科学 | 623篇 |
基础医学 | 5945篇 |
口腔科学 | 1635篇 |
临床医学 | 3310篇 |
内科学 | 7888篇 |
皮肤病学 | 702篇 |
神经病学 | 3961篇 |
特种医学 | 1644篇 |
外国民族医学 | 3篇 |
外科学 | 5797篇 |
综合类 | 1970篇 |
一般理论 | 34篇 |
预防医学 | 2586篇 |
眼科学 | 596篇 |
药学 | 3125篇 |
28篇 | |
中国医学 | 138篇 |
肿瘤学 | 2611篇 |
出版年
2023年 | 236篇 |
2022年 | 570篇 |
2021年 | 1439篇 |
2020年 | 852篇 |
2019年 | 1242篇 |
2018年 | 1915篇 |
2017年 | 1222篇 |
2016年 | 1669篇 |
2015年 | 1886篇 |
2014年 | 2236篇 |
2013年 | 2847篇 |
2012年 | 3035篇 |
2011年 | 2455篇 |
2010年 | 2270篇 |
2009年 | 1800篇 |
2008年 | 2039篇 |
2007年 | 2023篇 |
2006年 | 1854篇 |
2005年 | 1704篇 |
2004年 | 1485篇 |
2003年 | 1074篇 |
2002年 | 904篇 |
2001年 | 587篇 |
2000年 | 670篇 |
1999年 | 587篇 |
1998年 | 337篇 |
1997年 | 280篇 |
1996年 | 245篇 |
1995年 | 174篇 |
1994年 | 187篇 |
1993年 | 172篇 |
1992年 | 359篇 |
1991年 | 295篇 |
1990年 | 291篇 |
1989年 | 259篇 |
1988年 | 223篇 |
1987年 | 199篇 |
1986年 | 203篇 |
1985年 | 178篇 |
1984年 | 149篇 |
1983年 | 89篇 |
1982年 | 89篇 |
1981年 | 63篇 |
1980年 | 71篇 |
1979年 | 89篇 |
1977年 | 56篇 |
1972年 | 69篇 |
1971年 | 66篇 |
1970年 | 58篇 |
1968年 | 73篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
Marcelo Biscegli Jatene Estela Azeka Edmar Atik Arlindo Riso Carla Tanamati Miguel Barbero Marcial Sergio Almeida de Oliveira 《The Journal of heart and lung transplantation》2005,24(5):638-641
A 28-month-old boy, weighing 11 kg, with severe dilated cardiomyopathy, was transplanted on December 1995. Hypertension and supraventricular tachycardia were detected in the immediate post-operative period, with favorable outcome. After 5 months of clinically asymptomatic follow-up, a dilation in the ascending aorta was observed on routine echocardiogram. Nuclear magnetic resonance imaging (NMRI) confirmed an ascending aortic aneurysm, with a diameter of 38 mm. An operation was performed, a bovine pericardium patch was sutured with reconstruction of the aortic wall, excluding the aneurysm. Good recovery was obtained and the child was discharged on Day 7 postoperatively. A post-operative echocardiogram showed absence of the aortic aneurysm and good surgical results. Another NMRI was done 5 months later, showing an intact ascending aorta. After 64 months, the patients clinical condition was confirmed as normal by echocardiogram. Surgical treatment was successful and the positive results have been maintained. 相似文献
104.
Melaine de Almeida Lawall Marcelo Macedo Crivelini 《Journal of applied oral science : revista FOB》2006,14(4):276-280
Leukoplakias are oral lesions that may have many clinical and histological aspects and they are usually associated with malignancy when dysplastic alterations are shown. However, these transformations may occur in non-dysplastic lesions that show harmless clinical aspect. For this reason, the proposal was to study the p53 and PCNA immunohistochemical expression in non-dysplastic leukoplakias, trying to correlate the results only with the epithelial keratinization degree. For this, 24 leukoplakias degrees I, II and III of Grinspan were used, all of them located in oral mucosa. Most of the leukoplakias showed p53 and PCNA expression in their different keratinization degrees. The p53 marking was confined to the basal and parabasal layers, while the PCNA marking occurred in practically all epithelial layers. The expression pattern of these markers was histologically and statistically similar between the lesions with these keratinization variations. It was evident that non-dysplastic epithelium of leukoplakias showed submicroscopical signs of alterations that lead to malignant transformation, and that the keratinization degree did not correlate to a greater risk of this event. 相似文献
105.
106.
Silvio Taschieri Massimo Del Fabbro Tiziano Testori Luca Francetti Roberto Weinstein 《Journal of oral and maxillofacial surgery》2006,64(2):235-242
PURPOSE: The introduction of microsurgical instruments and magnification devices has brought advantages in root-end management and the application of root-end filling materials. The main purpose of this prospective clinical study was to monitor the outcome of ultrasonic root-end preparation using magnification loupes or an endoscope. Tooth location and the presence of post restoration were also examined as potentially affecting the outcome. MATERIALS AND METHODS: Teeth treated surgically showed a periradicular lesion of strictly endodontic origin. A total of 59 patients were included in the study, according to specific selection criteria. Following the reflection of a full mucoperiosteal tissue flap, residual soft tissues were curetted, root ends were resected, and root-end cavities were prepared ultrasonically with a zirconium nitrate tip, and zinc oxide EBA-reinforced cement root-end fillings were placed. Thirty-two root-end management procedures were performed using magnification loupes and 39 using an endoscope. All cases followed for a period of 1 year were classified into 3 groups (success, uncertain healing, and failure) according to radiographic and clinical criteria. RESULTS: Of the 71 teeth evaluated at 1-year follow-up, 67 teeth (92.95%) successfully healed, 3 teeth had uncertain healing, and 2 failed. In the group using endoscopy, 94.9% of successful healing was achieved, while for the other group, 90.6% was recorded. We found no statistically significant differences in treatment results related to the arch (P = .20), post restoration (P = .21), or type of magnification device (P = .08). CONCLUSIONS: In the present study, adherence to a strict endodontic surgical protocol and the use of modern surgical endodontic procedures, together with visual magnifications, resulted in an overall high success rate. 相似文献
107.
Andr ia Kist Fernandes Felipe Mallmann Ana Maria Pasquali Steinhorst Fernando Lopes Nogueira Eduardo Mü ller vila Dumitriu Zunino Saucedo Francisco Juchem Machado Marcelo Greg rio Raymundi S rgio Saldanha Menna Barreto Paulo de Tarso Roth Dalcin 《The Journal of asthma》2003,40(6):683-690
Asthma patients that depend on emergency department (ED) services are generally considered to have extremely poor disease control and prognosis. It is important to identify characteristics related to poor disease control and frequent visits to the ED to apply appropriate clinical management. This study comprised a cross-sectional survey of consecutive patients with asthma exacerbation (age ≥12 years) presenting at the adult ED of a large, tertiary care, university-affiliated hospital over a 2-month period. The frequent visitors (FV) were defined by ≥3 visits to the ED in the preceding year, and the occasional visitors (OV) by ≤2 visits. Eighty-six patients (61 females and 25 males) were included in the study (mean age 38 ± 18 years). Of these patients, 51.2% were FV and 48.8% were OV. Sixty-nine percent had annual income lower than A$3000 and 66.3% had ≤8 years of the formal education. Only 18.6% had used inhaled corticosteroids, 79.1% identified the asthma attack severity, 70.9% increased or initiated inhaled β-agonist, 20.9% increased or initiated steroid therapy, and 55.8% had an asthma action plan for attack. The number of hospital admissions in past year (OR 4.3, P = .02), use of home nebulizer (OR 3.6, P = .05) and the lack of a written asthma action plan (OR 3.3, P = .03) were independently associated with frequent visits to the ED. We conclude that a substantial proportion of the patients that visit the ED are FV. These patients are more likely to have hospital admission in the past year, to use a home nebulizer, and to lack a written asthma action plan. They should be considered the most important target for asthma education. 相似文献
108.
Alan A Arslan Anne Zeleniuch-Jacquotte Annekatrin Lukanova Yelena Afanasyeva Joseph Katz Mortimer Levitz Giuseppe Del Priore Paolo Toniolo 《Cancer epidemiology, biomarkers & prevention》2006,15(11):2123-2130
Epidemiologic evidence suggests that a full-term pregnancy may affect maternal risk of breast cancer later in life. The objective of this cross-sectional study was to compare circulating levels of maternal hormones affecting breast differentiation (human chorionic gonadotropin and prolactin) and proliferation [alpha-fetoprotein, insulin-like growth factor I (IGF-I), and estradiol] between women at a low to moderate risk (Asians and Hispanics), as compared with women at a high risk for breast cancer (Caucasians and African-Americans). Between May 2002 and December 2004, a total of 586 pregnant women were approached during a routine prenatal visit. Among them, 450 women (206 Caucasian, 126 Asian, 88 Hispanic, and 30 African-American) met the inclusion criteria and signed the informed consent. Only singleton pregnancies were considered. Blood samples were drawn during the second trimester of pregnancy. Laboratory analyses were done using the IMMULITE 2000 immunoassay system. Gestational age standardized mean levels of estradiol, IGF-I, and prolactin were significantly higher in Hispanic women compared with Caucasian women. Mean concentration of IGF-I was significantly higher in African-American women compared with Caucasian and Asian women. No significant differences in pregnancy hormone levels were observed between Caucasian and Asian (predominantly second-generation Chinese) women in this study. Irrespective of ethnicity, women who had their first pregnancy had substantially higher mean levels of alpha-fetoprotein, human chorionic gonadotropin, estradiol, and prolactin compared with women who previously had at least one full-term pregnancy. These data suggest that circulating pregnancy hormone levels may explain some of the ethnic differences in breast cancer risk. 相似文献
109.
110.