全文获取类型
收费全文 | 3381459篇 |
免费 | 239763篇 |
国内免费 | 8795篇 |
专业分类
耳鼻咽喉 | 46867篇 |
儿科学 | 112192篇 |
妇产科学 | 94974篇 |
基础医学 | 478288篇 |
口腔科学 | 94477篇 |
临床医学 | 304030篇 |
内科学 | 660505篇 |
皮肤病学 | 79143篇 |
神经病学 | 273884篇 |
特种医学 | 130947篇 |
外国民族医学 | 1047篇 |
外科学 | 510115篇 |
综合类 | 69463篇 |
现状与发展 | 6篇 |
一般理论 | 1192篇 |
预防医学 | 258154篇 |
眼科学 | 76927篇 |
药学 | 249415篇 |
9篇 | |
中国医学 | 6797篇 |
肿瘤学 | 181585篇 |
出版年
2018年 | 36133篇 |
2017年 | 27613篇 |
2016年 | 31947篇 |
2015年 | 36106篇 |
2014年 | 49746篇 |
2013年 | 75106篇 |
2012年 | 100037篇 |
2011年 | 106197篇 |
2010年 | 63970篇 |
2009年 | 61170篇 |
2008年 | 99932篇 |
2007年 | 106638篇 |
2006年 | 108601篇 |
2005年 | 104488篇 |
2004年 | 100683篇 |
2003年 | 97463篇 |
2002年 | 94586篇 |
2001年 | 158033篇 |
2000年 | 161957篇 |
1999年 | 136942篇 |
1998年 | 39750篇 |
1997年 | 35258篇 |
1996年 | 35515篇 |
1995年 | 34185篇 |
1994年 | 31634篇 |
1993年 | 29670篇 |
1992年 | 108015篇 |
1991年 | 104691篇 |
1990年 | 101934篇 |
1989年 | 98775篇 |
1988年 | 90979篇 |
1987年 | 89326篇 |
1986年 | 84281篇 |
1985年 | 80541篇 |
1984年 | 59837篇 |
1983年 | 51382篇 |
1982年 | 30607篇 |
1981年 | 27186篇 |
1979年 | 54265篇 |
1978年 | 38297篇 |
1977年 | 32826篇 |
1976年 | 30583篇 |
1975年 | 33006篇 |
1974年 | 38864篇 |
1973年 | 37098篇 |
1972年 | 35175篇 |
1971年 | 32576篇 |
1970年 | 30394篇 |
1969年 | 29179篇 |
1968年 | 27049篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
ABSTRACT: Background: Although increases in perinatal mortality risk associated with fetal macrosomia are well documented, the optimal route of delivery for fetuses with suspected macrosomia remains controversial. The objective of this investigation was to assess the risk of neonatal death among macrosomic infants delivered vaginally compared with those delivered by cesarean section. Methods: Data were derived from the U.S. 1995–1999 Linked Live Birth‐Infant Death Cohort files and term (37–44 wk), single live births to United States resident mothers selected. A proportional hazards model was used to analyze the risk of neonatal death associated with cesarean delivery among 3 categories of macrosomic infants (infants weighing 4,000–4,499 g; 4,500–4,999 g; and 5,000+ g). Results: After controlling for maternal characteristics and complications, the adjusted hazard ratio for neonatal death associated with cesarean delivery among the 3 categories of macrosomic infants was 1.40, 1.30, and 0.85. Conclusions: Although cesarean delivery may reduce the risk of death for the heaviest infants (5,000+ g), the relative benefit of this intervention for macrosomic infants weighing 4,000–4,999 g remains debatable. Thus, policies in support of prophylactic cesarean delivery for suspected fetal macrosomia may need to be reevaluated. (BIRTH 33:4 December 2006) 相似文献
72.
73.
74.
75.
76.
F. Spöler M. Först Y. Marquardt D. Hoeller H. Kurz H. Merk F. Abuzahra 《Skin research and technology》2006,12(4):261-267
BACKGROUND: Three dimensional skin equivalents are widely used in dermatopharmacological and toxicological studies and as autologous transplants in wound healing. In pharmacology, there is tremendous need for monitoring the response of engineered skin equivalents to external treatment. Transplantation of skin equivalents for wound healing requires careful verification of their quality prior to transplantation. Optical coherence tomography (OCT) is a non-contact, non-destructive imaging technique for living tissues offering the potential to fulfill these needs. This work presents an analysis of OCT for high-resolution monitoring of skin equivalents at different stages during the culture process. METHODS: We developed a high-resolution OCT imaging setup based on a commercially available OCT system. A broadband femtosecond laser light source replaces the original superluminescence diode. Tomograms of living skin equivalents were recorded with an axial resolution of 3 mum and correlated with histology and immunofluorescence images. Comparison with standard low-resolution OCT is presented to emphasize the advantages of high-resolution OCT for this application. RESULTS: OCT is particularly able to distinguish between different layers of skin equivalents including stratum corneum, epidermal and dermal layer as well as the basement membrane zone. The high-resolution OCT scans correlate closely with two key benchmarks, histology and immunofluorescence imaging. CONCLUSIONS: This study clearly demonstrates the benefits of high-resolution OCT for identifying living tissue structure and morphology. Compared with the current gold standard histology, OCT offers non-destructive tissue imaging, enabling high-resolution evaluation of living tissue morphology and structure as it evolves. 相似文献
77.
K M Sarraf M Abdalla O Al-Omari M G Sarraf 《Ultrasound in obstetrics & gynecology》2006,27(2):220-221
We report the case of a 38-year-old woman who presented with chronic lower abdominal pain. Her past medical history included a splenectomy due to abdominal trauma. Ultrasound examination revealed four pelvic tumors which, upon laparotomy, were found to be the result of splenosis. Approximately 100 cases of splenosis have been reported but only a minority of them have been published in the gynecological literature. Our case indicates that those involved in pelvic scanning (even of asymptomatic women) and/or treating those complaining of lower abdominal pain or presenting with pelvic tumors should be aware of splenosis as a possible diagnosis. 相似文献
78.
79.
80.
H J Kim C H Kang Y T Kim S-W Sung J H Kim S M Lee C-G Yoo C-T Lee Y W Kim S K Han Y-S Shim J-J Yim 《The European respiratory journal》2006,28(3):576-580
Although surgical lung resection could improve prognosis in some patients with multidrug-resistant tuberculosis (MDR-TB), there are no reports on the optimal candidates for this surgery. The aim of the present study was to elucidate the prognostic factors for surgery in patients with MDR-TB. Patients who underwent lung resection for the treatment of MDR-TB between March 1993 and December 2004 were included in the present study. Treatment failure was defined as greater than or equal to two of the five cultures recorded in the final 12 months of treatment being positive, any one of the final three cultures being positive, or the patient having died during treatment. The variables that affected treatment outcomes were identified through univariate and multivariate logistic regression analysis. In total, 79 patients with MDR-TB were included in the present study. The treatment outcomes of 22 (27.8%) patients were classified as failure. A body mass index <18.5 kg x m(-2), primary resistance, resistance to ofloxacin and the presence of a cavitary lesion beyond the range of the surgical resection were associated with treatment failure. Low body mass index, primary resistance, resistance to ofloxacin and cavitary lesions beyond the range of resection are possible poor prognostic factors for surgical lung resection in multidrug-resistant tuberculosis patients. 相似文献