全文获取类型
收费全文 | 1291篇 |
免费 | 108篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 40篇 |
妇产科学 | 23篇 |
基础医学 | 138篇 |
口腔科学 | 31篇 |
临床医学 | 139篇 |
内科学 | 287篇 |
皮肤病学 | 21篇 |
神经病学 | 42篇 |
特种医学 | 185篇 |
外科学 | 111篇 |
综合类 | 63篇 |
预防医学 | 96篇 |
眼科学 | 16篇 |
药学 | 61篇 |
肿瘤学 | 163篇 |
出版年
2022年 | 10篇 |
2021年 | 23篇 |
2020年 | 15篇 |
2019年 | 21篇 |
2018年 | 32篇 |
2017年 | 25篇 |
2016年 | 19篇 |
2015年 | 21篇 |
2014年 | 24篇 |
2013年 | 44篇 |
2012年 | 53篇 |
2011年 | 60篇 |
2010年 | 49篇 |
2009年 | 51篇 |
2008年 | 42篇 |
2007年 | 72篇 |
2006年 | 76篇 |
2005年 | 44篇 |
2004年 | 52篇 |
2003年 | 43篇 |
2002年 | 32篇 |
2001年 | 40篇 |
2000年 | 38篇 |
1999年 | 24篇 |
1998年 | 35篇 |
1997年 | 35篇 |
1996年 | 44篇 |
1995年 | 25篇 |
1994年 | 14篇 |
1993年 | 25篇 |
1992年 | 20篇 |
1991年 | 18篇 |
1990年 | 8篇 |
1989年 | 32篇 |
1988年 | 21篇 |
1987年 | 22篇 |
1986年 | 16篇 |
1985年 | 19篇 |
1984年 | 20篇 |
1983年 | 11篇 |
1982年 | 9篇 |
1981年 | 11篇 |
1980年 | 25篇 |
1979年 | 16篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 11篇 |
1975年 | 6篇 |
1968年 | 7篇 |
1965年 | 6篇 |
排序方式: 共有1421条查询结果,搜索用时 15 毫秒
1.
Coronary artery bypass grafts: visualization with MR imaging 总被引:1,自引:0,他引:1
2.
A S Bansal R Chee V Nagendran A Warner G Hayman 《Journal of investigational allergology & clinical immunology》2007,17(3):189-191
Brazil nuts are the second most frequent cause of nut allergy in the United Kingdom. We report the case of a 20-year-old woman with documented Brazil nut allergy who developed widespread urticaria and mild dyspnea after intercourse with her boyfriend who had earlier consumed Brazil nuts. Skin prick testing with the boyfriend's semen after Brazil nut consumption confirmed significant reactivity whereas a sample before nut consumption was negative. We believe this to be the first case of a sexually transmitted allergic reaction. 相似文献
3.
Human immunodeficiency virus infection in disadvantaged adolescents. Findings from the US Job Corps 总被引:3,自引:0,他引:3
OBJECTIVE--To describe the human immunodeficiency virus (HIV) epidemic among socially and educationally disadvantaged young persons in the United States. DESIGN.-We analyzed demographic and geographic findings from the screening of Job Corps students for antibody to HIV. SETTING--The Job Corps is a federal training program for disadvantaged, out-of-school youth. POPULATION SCREENED--Residential students aged 16 to 21 years who entered the Job Corps from October 1987 through February 1990. MAIN OUTCOME MEASURE--Rates of observed HIV infection in entering students, stratified by demographic and geographic features. RESULTS--Of 137,209 Job Corps students screened, 488 were HIV seropositive (3.6 per 1000), a seroprevalence rate higher than that among military applicants of the same age. Overall seroprevalence was slightly higher in male (3.7 per 1000) than in female (3.2 per 1000) Job Corps students, but among those students aged 16 and 17 years, seroprevalence was higher among females (2.3 per 1000) than among males (1.5 per 1000) (P less than .05). For students aged 16 to 21 years, seroprevalence increased with year of age: 1.8 per 1000 per year for males and 0.7 per 1000 per year for females. Among those aged 21 years, HIV prevalence was 8.9 per 1000. For black and Hispanic students from large Northeastern cities, seroprevalence increased by 4.3 per 1000 per year of age and reached 24.8 per 1000 (one of 40) in students aged 21 years. However, among students from rural areas and small towns, HIV seroprevalence was disproportionately high in the Southeast. Compared with recently described US patients with the acquired immunodeficiency syndrome, HIV-infected students who entered the Job Corps were much more likely to be female. CONCLUSIONS--These findings show that disadvantaged, out-of-school adolescents are at high risk for HIV infection. The screening results identified surprisingly high seroprevalence in the southeastern United States and demonstrated a marked shift in the HIV epidemic to young women. Controlling the HIV epidemic among teenagers must include interventions that will reach adolescents early and outside of the formal educational system. 相似文献
4.
Metastatic tumours of the testes are uncommon, making up little more than 2% of all testicular neoplasms. The most frequent primary sites are the lung and prostate. Only rarely do these lesions present clinically either as the first sign of malignant disease or as a complicating factor during the course of known disease. The authors present two cases illustrating both of these occurrences. The first, a man with carcinoma of the common bile duct, initially had a mass in the testicle and the second, a patient with carcinoma of the prostate, had his clinical course complicated by a symptomatic metastasis to the right testis. The authors also reviewed their local autopsy experience and identified 16 more cases. Metastases were grossly visible in 38% (6 of 16). The most frequent primary sites were lung (four cases), stomach (four) and prostate (three). Routes of spread as well as possible explanations for the low incidence are discussed. 相似文献
5.
6.
7.
8.
PURPOSETo describe the in vivo CT appearance of acute intracerebral blood clots formed from anemic platelet-depleted blood.METHODSThree patients with intracerebral hemorrhage secondary only to thrombocytopenia were examined with CT within 2 1/2 hours after the onset of clinical symptoms.RESULTSThere were no unusual CT features found in the intracerebral hemorrhages of patients with only thrombocytopenia. Specifically, a hyperdense zone(s) surrounded by areas of decreased density was identified.CONCLUSIONClot retraction (which cannot occur in patients with severe thrombocytopenia) is not necessary for the CT appearance of acute intracerebral hemorrhage. 相似文献
9.
Ehsanollah Esfandiari Michael Bailey Christopher R Stokes Timothy M Cox Martin J Evans Alison R Hayman 《Journal of bone and mineral research》2006,21(9):1367-1376
TRACP, a marker of osteoclasts, is also expressed by cells of the immune system. We identified a novel function for TRACP in the dendritic cell. DCs from TRACP knockout mice have impaired maturation and trigger reduced Th1 responses in vivo. We postulate that TRACP has an important role in the presentation of antigens to T cells. INTRODUCTION: TRACP is highly expressed by osteoclasts, activated macrophages, and dendritic cells (DCs). Knockout mice lacking TRACP have an intrinsic defect in osteoclastic resorption and macrophages that display abnormal immunomodulatory responses and cytokine secretion profiles. Our aim in this study was to investigate the significance of TRACP in the inductive phase of the immune response by examining dendritic cells from TRACP(-/-) mice. MATERIALS AND METHODS: Maturational state and function of leukocyte subsets in mice was assessed by flow cytometry. The ability of the immune system to respond to nonspecific activation and to specific antigen was assessed by delayed type hypersensitivity and the presence of isotype-specific serum antibody in vivo and T-cell proliferation and cytokine production in vitro. RESULTS: The ability of lipopolysaccharide (LPS) to upregulate MHC II and CD80 in DCs from TRACP(-/-) mice was reduced compared with wildtype mice, although production of IL-10 by DCs from TRACP-deficient animals was increased. T- and B-cell responses not involving antigen presentation (anti-CD3, TNP-ficoll) were normal in TRACP(-/-) mice, but responses to T-dependent antigens were impaired. Specifically, TRACP(-/-) mice had defective delayed hypersensitivity responses to picryl chloride and reduced proliferative responses to ovalbumin compared with wildtype mice. In response to ovalbumin, but not anti-CD3, T cells from TRACP(-/-) mice produced less interferon-gamma (IFN-gamma), but there was no difference in IL-4 production: TRACP(-/-) mice also produced less ovalbumin (OVA)-specific IgG2a after immunization. CONCLUSIONS: The finding that DCs from TRACP(-/-) mice have impaired maturation and defective Th1 responses shows that TRACP is important for polarizing responses in na?ve T cells to antigen-presented dendritic cells. 相似文献
10.
Genotype-phenotype correlation for nucleotide substitutions in the IgII- IgIII linker of FGFR2 总被引:6,自引:3,他引:3