全文获取类型
收费全文 | 756篇 |
免费 | 98篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 31篇 |
妇产科学 | 35篇 |
基础医学 | 121篇 |
口腔科学 | 29篇 |
临床医学 | 88篇 |
内科学 | 131篇 |
皮肤病学 | 8篇 |
神经病学 | 34篇 |
特种医学 | 56篇 |
外科学 | 122篇 |
综合类 | 14篇 |
预防医学 | 107篇 |
药学 | 40篇 |
中国医学 | 1篇 |
肿瘤学 | 42篇 |
出版年
2021年 | 6篇 |
2020年 | 12篇 |
2019年 | 14篇 |
2018年 | 13篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 20篇 |
2014年 | 17篇 |
2013年 | 34篇 |
2012年 | 43篇 |
2011年 | 29篇 |
2010年 | 34篇 |
2009年 | 30篇 |
2008年 | 26篇 |
2007年 | 40篇 |
2006年 | 41篇 |
2005年 | 24篇 |
2004年 | 31篇 |
2003年 | 19篇 |
2002年 | 20篇 |
2001年 | 19篇 |
2000年 | 12篇 |
1999年 | 15篇 |
1998年 | 21篇 |
1997年 | 21篇 |
1996年 | 15篇 |
1995年 | 12篇 |
1994年 | 22篇 |
1993年 | 12篇 |
1992年 | 14篇 |
1991年 | 10篇 |
1990年 | 14篇 |
1989年 | 9篇 |
1988年 | 18篇 |
1987年 | 10篇 |
1986年 | 15篇 |
1985年 | 20篇 |
1984年 | 10篇 |
1983年 | 9篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 5篇 |
1979年 | 9篇 |
1975年 | 4篇 |
1973年 | 5篇 |
1972年 | 7篇 |
1970年 | 4篇 |
1969年 | 4篇 |
1968年 | 6篇 |
1939年 | 4篇 |
排序方式: 共有862条查询结果,搜索用时 15 毫秒
61.
Semenza JC Ziogas A Largent J Peel D Anton-Culver H 《American journal of epidemiology》2001,153(9):851-859
The majority of renal cell carcinomas (RCCs) are sporadic, and increasing incidence rates suggest that such environmental risk factors as smoking play a role in the etiology of the disease. Cases with RCC were selected from the population-based cancer registry of Orange County, California, between 1994 and 1997; controls were recruited by telephone using random digit dialing. A total of 115 case and 259 control subjects were genotyped for N-acetyltransferase 2 (NAT2), which codes for a polymorphic enzyme involved in tobacco-carcinogen metabolism. Subjects with slow acetylator genotypes were found to be at twofold increased risk (odds ratio (OR) = 1.8; 95 percent confidence interval (CI): 1.1, 2.9) of RCC. Although cancer risk doubled among smokers (OR = 2.2; 95 percent CI: 1.3, 3.7), stratified analysis revealed gene-environment interaction among slow acetylators that smoked (OR = 3.2; 95 percent CI: 1.7, 6.1) compared with rapid acetylators that smoked (OR = 1.4; 95 percent CI: 0.7, 2.9). A dose response was found for pack-years among slow acetylators (p < 0.01) but not among rapid acetylators (p = 0.06). Although smoking is a well-established risk factor of RCC, our data suggest that the risk is pronounced among slow rather than rapid acetylators. 相似文献
62.
Germ-line msh6 mutations in colorectal cancer families. 总被引:15,自引:0,他引:15
R D Kolodner J D Tytell J L Schmeits M F Kane R D Gupta J Weger S Wahlberg E A Fox D Peel A Ziogas J E Garber S Syngal H Anton-Culver F P Li 《Cancer research》1999,59(20):5068-5074
Hereditary nonpolyposis colorectal carcinoma (HNPCC) is due primarily to inherited mutations in two mismatch repair genes, MSH2 and MLH1, whereas germ-line mutations in other mismatch repair genes are rare. We examined the frequency of germ-line msh6 mutations in a population-based series of 140 colorectal cancer patients, including 45 sporadic cases, 91 familial non-HNPCC cases, and 4 HNPCC cases. Among the 91 population-based familial non-HNPCC cases, germ-line msh6 mutations were found in 6 patients (7.1% of probands analyzed; median age at diagnosis, 61 years). These mutations included a splice site mutation, a frameshift mutation, two missense mutations that were demonstrated to be loss of function mutations, and two missense mutations for which functional studies were not possible. In contrast, germ-line msh6 mutations were not found in any of the 45 sporadic cases and the 4 HNPCC cases in the population-based series or in the second series of 58 clinic-based, primarily HNPCC families. Our data suggest that germ-line msh6 mutations predispose individuals to primarily late-onset, familial colorectal carcinomas that do not fulfill classic criteria for HNPCC. 相似文献
63.
64.
65.
66.
67.
68.
This paper aims to contribute to the literature on the relationship between productive and healthy ageing as two key theoretical
concepts in contemporary ageing. Specifically, volunteering as a productive activity in later life has been associated with
social and health benefits for older people. Evidence from the literature has generally focused on global outcomes, such as
mortality and self-rated health, or on measures of psychological well-being. This study explored whether volunteering is protective
of an important adverse health outcome in later life, that of fall-related hip fracture, utilising data from a case control
study of 387 participants. The results showed that volunteer activity in older age remained significantly protective of hip
fracture risk [OR: 0.61 (0.38–0.99)], independent of social and physical activity, social support and health status, supporting
the hypothesis of a relationship between the concepts of productive and healthy ageing. Whilst further studies are clearly
needed to establish causality, these results suggest that health benefits of volunteering in later life might be more extensive
than previous studies have shown. 相似文献
69.
I J Stewart S Peel 《American journal of reproductive immunology (New York, N.Y. : 1989)》1999,41(6):423-427
PROBLEM: Mouse granulated metrial gland (GMG) cells are maternal, cytotoxic cells found in the uterine wall in pregnancy. In vivo, they are cytotoxic to layer 1 labyrinthine placental cells. In an in vitro system, granulated metrial gland cells are highly cytotoxic to Wehi 164 fibrosarcoma cells. In this study the role of interleukin (IL)-3 and tumour necrosis factor (TNF)-alpha in granulated metrial gland cell cytotoxic activity was investigated. METHOD OF STUDY: Chromium-release cytotoxicity assays using mouse metrial gland effector cells and Wehi 164 target cells with the addition of IL-3 or an antibody to TNF-alpha. RESULTS: An antibody to TNF-alpha reduced the level of cytotoxic activity. IL-3 had no effect on the level of cytotoxicity. CONCLUSION: Mouse granulated metrial gland cells kill using a TNF-alpha mediated mechanism which is independent of IL-3 stimulation. 相似文献
70.
Segal I; Sharer NM; Kay PM; Gutteridge JM; Braganza JM 《QJM : monthly journal of the Association of Physicians》1996,89(1):45-53
Vitamin C can be used to overcome oxidative stress and ease pain in chronic
pancreatitis. But its use is deprecated in conditions of tissue iron
overload, because its bioactive form, ascorbate, can accelerate
free-radical reactions that are driven by transition metals. We measured
iron, ascorbate and copper in Sowetan Blacks (RSA) with chronic
pancreatitis, obtaining serum/plasma from 14 consecutive patients and 15
controls. Compared with data from corresponding groups in Manchester,
African samples had less ascorbate (p < 0.0001), but more caeruloplasmin
(p < 0.0001). African and British controls had comparable iron and
iron-binding capacity. Plasma from African patients had less ascorbate than
that from African controls (p < 0.005) and in six samples, ferritin
exceeded 300 micrograms/l (677 pmol/l). Low- molecular-mass iron or copper,
capable of participating in free radical reactions, was not detected.
British patients, had similar caeruloplasmin levels to African patients but
higher ascorbate levels. There is no evidence of iron overload in our
African samples. Outwardly healthy controls from Soweto have elevated
levels of caeruloplasmin, possibly to compensate for dietary deficiency of
ascorbate. Persistent oxidative stress is a unifying feature of chronic
pancreatitis, but its degree is higher in African than British patients.
Supplements of vitamin C should be safe in Blacks of southern Africa.
相似文献