全文获取类型
收费全文 | 11160篇 |
免费 | 625篇 |
国内免费 | 114篇 |
专业分类
耳鼻咽喉 | 184篇 |
儿科学 | 156篇 |
妇产科学 | 239篇 |
基础医学 | 1715篇 |
口腔科学 | 238篇 |
临床医学 | 889篇 |
内科学 | 1997篇 |
皮肤病学 | 563篇 |
神经病学 | 666篇 |
特种医学 | 716篇 |
外科学 | 1816篇 |
综合类 | 52篇 |
一般理论 | 1篇 |
预防医学 | 609篇 |
眼科学 | 186篇 |
药学 | 944篇 |
中国医学 | 156篇 |
肿瘤学 | 772篇 |
出版年
2023年 | 57篇 |
2022年 | 230篇 |
2021年 | 357篇 |
2020年 | 181篇 |
2019年 | 277篇 |
2018年 | 298篇 |
2017年 | 217篇 |
2016年 | 351篇 |
2015年 | 485篇 |
2014年 | 591篇 |
2013年 | 687篇 |
2012年 | 975篇 |
2011年 | 952篇 |
2010年 | 592篇 |
2009年 | 454篇 |
2008年 | 659篇 |
2007年 | 604篇 |
2006年 | 554篇 |
2005年 | 558篇 |
2004年 | 426篇 |
2003年 | 369篇 |
2002年 | 332篇 |
2001年 | 217篇 |
2000年 | 226篇 |
1999年 | 182篇 |
1998年 | 76篇 |
1997年 | 50篇 |
1996年 | 55篇 |
1995年 | 38篇 |
1994年 | 32篇 |
1993年 | 36篇 |
1992年 | 60篇 |
1991年 | 53篇 |
1990年 | 51篇 |
1989年 | 43篇 |
1988年 | 45篇 |
1987年 | 40篇 |
1986年 | 43篇 |
1985年 | 48篇 |
1984年 | 39篇 |
1983年 | 53篇 |
1982年 | 16篇 |
1981年 | 17篇 |
1980年 | 18篇 |
1979年 | 29篇 |
1978年 | 28篇 |
1977年 | 21篇 |
1976年 | 19篇 |
1974年 | 17篇 |
1973年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
85.
The nutrition transition in South Korea 总被引:11,自引:0,他引:11
BACKGROUND: An accelerating shift from infectious to noncommunicable diseases and concurrent shifts in diet, activity, and body composition are universal trends but are especially apparent in middle- and lower-income countries. A unique nutrition transition has occurred in South Korea, a country that modernized earlier than most Asian countries did. OBJECTIVE: The purpose of this analysis was to describe the South Korean nutrition transition, focusing on specific features that other countries might follow to retain the healthful elements of their traditional diets. DESIGN: We used secondary data on economics, dietary intake, anthropometry, and causes of death, including a series of comparable nationally representative dietary surveys (the National Nutrition Survey). RESULTS: The structure of South Korea's economy, along with the country's dietary and disease patterns, began an accelerated shift in the 1970s. Major dietary changes included a large increase in the consumption of animal food products and a fall in total cereal intake. Uniquely, the amount and rate of increase in fat intake have remained low in South Korea. South Korea also has a relatively low prevalence of obesity compared with other Asian countries with similar or much lower incomes. CONCLUSIONS: The nutrition transition in South Korea is unique. National efforts to retain elements of the traditional diet are thought to have shaped this transition in South Korea in the midst of rapid economic growth and the introduction of Western culture. 相似文献
86.
In this review of the scientific literature the relationship between retinoids, carotenoids, and mammary carcinogenesis is examined. Several retinoids have shown promise as chemopreventive agents against chemically induced mammary carcinogenesis in mice and especially in rats. The most promising retinoids are retinyl acetate (RA) and N-(4-hydroxyphenyl)retinamide (4-HPR, fenretinide). In rats, dietary administration of these retinoids reduced tumor incidence and multiplicity, and increased the latency of DMBA or MNU-induced mammary cancers. In mice, 4-HPR reduced the number of hyperplastic alveolar nodules and the number of tumors in MTV- and MTV+ mice, respectively. Among retinoids, 4-HPR is at present the most promising analogue, due to its ability to concentrate in the mammary gland. The combination of 4-HPR with tamoxifen not only is more effective in suppressing breast cancer than either agent alone, but also inhibits the appearance of subsequent cancers following the surgical removal of the first tumor. These studies suggest that retinoids, like tamoxifen, may be applicable to the prevention of contralateral breast cancer in women who underwent breast cancer surgery. It is also becoming evident that differentiation therapy and chemoprevention can become attractive alternative approaches to intensive cytotoxic chemotherapy. The role of carotenoids in the prevention of mammary carcinogenesis, however, is ambiguous. Poor absorption and low levels of carotenoids that reach the target tissues complicate interpretation of data in rodent models of mammary carcinogenesis. Very few animal studies are presently available in which purified carotenoids were found effective against mammary carcinogenesis. These results do not justify undertaking clinical evaluation of individual carotenoids against breast cancer at this time. 相似文献
87.
Gonzales AJ; Christensen JG; Preston RJ; Goldsworthy TL; Tlsty TD; Fox TR 《Carcinogenesis》1998,19(7):1173-1183
88.
Moon WK Chang KH Weinmann HJ Koh YH Im JG Yeon KM Han MC 《AJR. American journal of roentgenology》2000,174(5):1385-1390
OBJECTIVE: The objective of this study was to compare enhancement patterns of a blood-pool contrast agent, Gadomer-17, with those of gadopentetate dimeglumine in bacterial abscesses and VX2 carcinoma in rabbits. MATERIALS AND METHODS: Fourteen rabbits with experimentally induced bacterial abscesses and VX2 carcinoma in both thighs underwent dynamic contrast-enhanced MR imaging with Gadomer-17 and gadopentetate dimeglumine at a 24-hr interval. The enhancement ratios (postcontrast to precontrast signal intensities) of lesions in the same animal were assessed and correlated with microvessel density. RESULTS: For Gadomer-17, the enhancement ratio of the abscesses (1.66 +/- 0.39) peaked 15 min after the injection, while that of the carcinoma (2.05 +/- 0.16) peaked at 10 min. The enhancement ratios of the carcinoma were consistently higher than those of the abscesses up to 30 min. For gadopentetate dimeglumine, peak enhancement ratio of the abscesses (2.30 +/- 0.75) was seen 5 min after the injection, while that of the carcinoma (2.32 +/- 0.51) was seen at 3 min. The enhancement ratios of the carcinomas were significantly higher at 1 min, but significantly lower at 20-30 min, compared with those of the abscesses, as a result of rapid decrease of enhancement ratios in the carcinomas. The microvessel density was 9.8 +/- 5.2 vessels per field of view for the abscesses and 36.3 +/- 9.5 vessels per field of view for the carcinoma (p < 0.001). CONCLUSION: Delayed peak enhancement and slow decay were found in both bacterial abscess and VX2 carcinoma with Gadomer-17, whereas early peak enhancement and rapid decay were found especially in VX2 carcinoma with gadopentetate dimeglumine. Enhancement ratios on MR imaging with a blood-pool contrast agent correlated well with the microvessel density in bacterial abscess and VX2 carcinoma. 相似文献
89.
Han DH Kwon OK Byun BJ Choi BY Choi CW Choi JU Choi SG Doh JO Han JW Jung S Kang SD Kim DJ Kim HI Kim HD Kim MC Kim SC Kim SC Kim Y Kwun BD Lee BG Lim YJ Moon JG Park HS Shin MS Song JH Suk JS Yim MB;Korean Society for Cerebrovascular Disease 《Acta neurochirurgica》2000,142(11):1263-73; discussion 1273-4
A co-operative study was conducted to determine the clinical characteristics of patients with moyamoya disease who were diagnosed and treated at neurosurgical institutes in Korea before 1995. Twenty-six hospitals contributed 505 cases and among them, the clinical characteristics of 334 patients with definite moyamoya disease were evaluated. The number of patients began to increase from the late 1980s, and after that approximately 20 patients were treated each year. There were two age peaks: from six to 15 and from 31 to 40 years of age. Haemorrhagic manifestations occurred in approximately 43% of the patients. The major clinical manifestations were haemorrhage in adults (62.4%) and ischaemia in children (61.2%). Overall 54.5% of the patients experienced decreased consciousness levels, mainly due to intracranial haemorrhage or cerebral infarction. In the patients with ischemic manifestations, the adult patients were more likely to have cerebral infarction than the pediatric patients (80% vs. 39%) and the pediatric patients were more likely to have TIA (61% vs. 25%). Thirty eight percent of the patients underwent bypass surgery and 53% of these procedures were performed bilaterally. Treatment policies, including indications for bypass surgery and commonly used drugs, were somewhat different according to the institution. Overall favorable outcome was 73%, and the most significant factor affecting poor outcome was haemorrhagic manifestation. This article describes the characteristics of 334 patients with moyamoya disease, who were diagnosed and treated at neurosurgical institutes in Korea before 1995. 相似文献
90.
Ja-Won Koo Il Joon Moon Woo Sub Shim So Young Moon Ji Soo Kim 《Otology & neurotology》2006,27(3):367-371
BACKGROUND: Horizontal canal benign paroxysmal positional vertigo is characterized by horizontal direction-changing nystagmus induced by lateral head turning in supine position. According to Ewald's second law, the direction of head turning that creates a stronger response represents the affected side in geotropic nystagmus and the healthy side in apogeotropic nystagmus. However, it may not always be possible to lateralize the involved ear only by comparing the intensity of the nystagmus. We studied the values of nystagmus induced by position change from sitting to supine in the lateralization of horizontal canal benign paroxysmal positional vertigo. METHODS: A retrospective study of 54 patients who had been diagnosed as having horizontal canal benign paroxysmal positional vertigo at the Dizziness Clinic of Seoul National University Bundang Hospital from May 2003 to February 2004 was performed. The directions of the nystagmus induced by lying down were compared with those determined by Ewald's second law. RESULTS: Of the 54 patients, 32 (20 apogeotropic and 12 geotropic) showed horizontal nystagmus induced by lying down. The nystagmus tended to be ipsilesional in apogeotropic patients (80%) and contralesional in their geotropic counterparts (75%). CONCLUSION: In horizontal canal benign paroxysmal positional vertigo, lying-down nystagmus mostly beats toward the involved ear in the apogeotropic type and directs to the healthy ear in the geotropic type. The direction of lying-down nystagmus may help lateralizing the involved ear in horizontal canal benign paroxysmal positional vertigo. 相似文献