全文获取类型
收费全文 | 3083992篇 |
免费 | 220704篇 |
国内免费 | 4440篇 |
专业分类
耳鼻咽喉 | 43218篇 |
儿科学 | 100229篇 |
妇产科学 | 83128篇 |
基础医学 | 450452篇 |
口腔科学 | 85720篇 |
临床医学 | 278422篇 |
内科学 | 591154篇 |
皮肤病学 | 68676篇 |
神经病学 | 240728篇 |
特种医学 | 117362篇 |
外国民族医学 | 676篇 |
外科学 | 464351篇 |
综合类 | 63191篇 |
现状与发展 | 13篇 |
一般理论 | 1044篇 |
预防医学 | 235572篇 |
眼科学 | 72208篇 |
药学 | 235485篇 |
18篇 | |
中国医学 | 6546篇 |
肿瘤学 | 170943篇 |
出版年
2021年 | 24007篇 |
2019年 | 24437篇 |
2018年 | 34042篇 |
2017年 | 25932篇 |
2016年 | 29201篇 |
2015年 | 32805篇 |
2014年 | 46019篇 |
2013年 | 68919篇 |
2012年 | 94620篇 |
2011年 | 100722篇 |
2010年 | 59847篇 |
2009年 | 56303篇 |
2008年 | 94322篇 |
2007年 | 100700篇 |
2006年 | 101621篇 |
2005年 | 98293篇 |
2004年 | 94132篇 |
2003年 | 90769篇 |
2002年 | 87839篇 |
2001年 | 145911篇 |
2000年 | 150076篇 |
1999年 | 125930篇 |
1998年 | 35443篇 |
1997年 | 31149篇 |
1996年 | 31452篇 |
1995年 | 29578篇 |
1994年 | 27215篇 |
1993年 | 25667篇 |
1992年 | 96976篇 |
1991年 | 94311篇 |
1990年 | 92447篇 |
1989年 | 88950篇 |
1988年 | 81533篇 |
1987年 | 79947篇 |
1986年 | 75050篇 |
1985年 | 71540篇 |
1984年 | 52942篇 |
1983年 | 44982篇 |
1982年 | 26248篇 |
1979年 | 48449篇 |
1978年 | 34072篇 |
1977年 | 28975篇 |
1976年 | 26997篇 |
1975年 | 29530篇 |
1974年 | 35029篇 |
1973年 | 33520篇 |
1972年 | 31694篇 |
1971年 | 29948篇 |
1970年 | 27597篇 |
1969年 | 26415篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
A Gyang S Mirando 《The European journal of contraception & reproductive health care》2006,11(4):319-321
A 41-year-old Chinese lady had a Gr?fenberg ring in utero for 15 years. During that period of time, she had one normal vaginal delivery a year after insertion, followed by an ectopic pregnancy 12 years later. We discuss the possible mechanism of action of the Gr?fenberg ring and sequelae of its prolonged presence in the uterus. 相似文献
993.
994.
Adrenal disorders in pregnancy. 总被引:1,自引:0,他引:1
995.
Rodger A Liddle 《Endocrinology & Metabolism Clinics of North America》2006,35(2):345-56, x
The endogenous pancreatic trypsin inhibitor, SPINK, is believed to limit enzyme activity in the pancreas and reduce the risk of pancreatitis. Recently, mutations in the SPINK1 gene have been associated with development of both acute and chronic pancreatitis. In most patients with SPINK1 mutations, the genetic variants do not cause the disease independently, but may act in concert with other genetic or environmental factors. Recent studies, using mice in which the trypsin inhibitor gene has been deleted or overexpressed, provide novel insights into the role of SPINK in pancreatic development and pancreatitis. 相似文献
996.
997.
Michael D Levitt Julie K Furne Michael Kuskowski John Ruddy 《Clinical gastroenterology and hepatology》2006,4(2):123-129
BACKGROUND & AIMS: Breath methane measurements reflect the in situ activity of the methanogenic colonic flora. Thirty-five years ago we found that 34% of healthy adult subjects were methane producers (breath methane level >1 ppm above atmospheric methane levels). The current study presents a new survey of breath methane levels designed to determine if the activity of the methanogenic flora has changed over the past 35 years. In addition, we review insights into the methanogenic flora that have resulted from breath methane measurements. METHODS: The end-alveolar breath methane concentrations of 212 healthy adults living in the Minneapolis area were determined via gas chromatography. The influence of sex, age, and bowel movement frequency on methane production was assessed. RESULTS: The findings that 36.4% of participants were methane producers, with a mean methane concentration in these producers of 16.6 ppm, are strikingly similar to the values of 33.6% and 15.2 ppm observed 35 years ago. Neither sex nor age showed a statistically significant relationship to methane production. There was a negative correlation between frequency of bowel movements and breath methane concentration in methane producers. CONCLUSIONS: The activity of the methanogenic flora of healthy adults remained remarkably stable over the past 35 years despite widespread antibiotic use and dietary changes. A literature review revealed that many associations have been shown between methane production and clinical states, but it remains to be determined if methanogens actively influence human physiology or are simply a marker of colonic function. 相似文献
998.
Elhaji Youssef A.; Stoica Ileana; Dennis Sheldon; Purisima Enrico O.; Lumbroso Rose; Beitel Lenore K.; Trifiro Mark A. 《Human molecular genetics》2006,15(9):1561
Human Molecular Genetics (2006) 15, 921931; 相似文献
999.
1000.
C.A. AMEZCUA H.R. MACDONALD† C.A. LUM W. YI‡ L.I. MUDERSPACH† L.D. ROMAN† & J.C. FELIX† 《International journal of gynecological cancer》2006,16(3):1336-1341
In this study, we examine the prevalence of finding isolated tumor cells (ITCs) in negative lymph nodes of endometrial cancer patients using immunohistochemistry. Seventy-six endometrial cancer patients with lymph nodes histologically negative for metastatic disease were examined. Nodal tissue sections were stained with anticytokeratin antibodies AE-1 and CAM 5.2. Nodes with single or groups of cells (two to four cells) < or =0.2 mm and showing cytokeratin reactivity were positive for ITCs. Findings were compared to features of the primary tumor and patient outcome. ITCs were present in 31 of 1712 lymph nodes. Fifteen (19.7%) patients had ITC-positive nodes. ITCs involved only pelvic nodes in nine cases, only para-aortic nodes in five cases, and pelvic and para-aortic in one case. Tumor in adnexa was the only pathologic feature associated with nodal ITCs (P= 0.0485). All 15 patients with nodal ITCs were alive at follow-up. One (6.7%) patient suffered recurrent disease but was alive at last encounter. Disease recurred in 5 (8.8%) of 57 patients without nodal ITCs. Two are alive without disease, two alive with disease, and one died from her cancer. In summary, a significant proportion of endometrial cancer patients have ITCs detected by immunohistochemistry in histologically negative regional lymph nodes. 相似文献