全文获取类型
收费全文 | 2453篇 |
免费 | 96篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 67篇 |
儿科学 | 86篇 |
妇产科学 | 8篇 |
基础医学 | 341篇 |
口腔科学 | 104篇 |
临床医学 | 231篇 |
内科学 | 580篇 |
皮肤病学 | 12篇 |
神经病学 | 202篇 |
特种医学 | 103篇 |
外科学 | 344篇 |
综合类 | 9篇 |
一般理论 | 1篇 |
预防医学 | 132篇 |
眼科学 | 28篇 |
药学 | 128篇 |
中国医学 | 1篇 |
肿瘤学 | 187篇 |
出版年
2023年 | 7篇 |
2022年 | 11篇 |
2021年 | 33篇 |
2020年 | 21篇 |
2019年 | 33篇 |
2018年 | 35篇 |
2017年 | 25篇 |
2016年 | 40篇 |
2015年 | 40篇 |
2014年 | 66篇 |
2013年 | 114篇 |
2012年 | 136篇 |
2011年 | 157篇 |
2010年 | 107篇 |
2009年 | 81篇 |
2008年 | 139篇 |
2007年 | 176篇 |
2006年 | 156篇 |
2005年 | 150篇 |
2004年 | 167篇 |
2003年 | 180篇 |
2002年 | 179篇 |
2001年 | 33篇 |
2000年 | 16篇 |
1999年 | 30篇 |
1998年 | 31篇 |
1997年 | 36篇 |
1996年 | 27篇 |
1995年 | 25篇 |
1994年 | 30篇 |
1993年 | 27篇 |
1992年 | 22篇 |
1991年 | 26篇 |
1990年 | 16篇 |
1989年 | 18篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 16篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 21篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 6篇 |
1978年 | 11篇 |
1977年 | 14篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1957年 | 2篇 |
排序方式: 共有2564条查询结果,搜索用时 15 毫秒
31.
Kalle Hakala Pekka Luukkonen Matti Vuoristo Heikki Järvinen Tatu A. Miettinen 《Journal of hepatology》1997,26(6):1306-1312
Background: Previous studies suggest only minor changes in bile acid metabolism after panproctocolectomy with ileal pouch construction.Aims/Methods: To investigate these changes further, we studied cholesterol absorption and serum, biliary and fecal non-cholesterol sterols and lipids in 12 ileal pouch patients and 10 controls.Results: In patients, cholesterol absorption was markedly reduced and was associated with low serum total and LDL cholesterol and LDL triglyceride levels, but surprisingly, cholesterol synthesis, as indicated by sterol-balance data or serum cholesterol precursor levels, was within low normal limits. The high proportions of serum plant sterol to cholesterol, particularly that of campesterol, were not related to cholesterol absorption, but were attributable to a markedly reduced biliary cholesterol secretion. Interestingly, in these patients the fractional absorption of campesterol was normal, whereas that of sitosterol, like cholesterol, was reduced and was positively related to the intestinal influx of cholesterol. The patients' serum cholestanol proportion was normal, but the proportion of the cholestanol formed during intestinal passage was significantly reduced (17.9% vs 65.2% in controls).Conclusions: Thus ileal pouch patients are characterized by sterol malabsorption, lowered serum total and LDL-cholesterol levels, but unexpectedly without any increase in cholesterol synthesis. The lack of high serum cholestanol, shown earlier frequently in unoperated patients with ulcerative colitis, may indicate reversible cholestasis, a finding deserving further exploration. 相似文献
32.
Frequency of hereditary nonpolyposis colorectal cancer 总被引:10,自引:0,他引:10
Jukka-Pekka Mecklin M.D. Heikki J. Järvinen M.D. Antti Hakkiluoto M.D. Hannu Hallikas M.D. Kari-Matti Hiltunen M.D. Niilo Härkönen M.D. Ilmo Kellokumpu M.D. Seppo Laitinen M.D. Jari Ovaska M.D. Jukka Tulikoura M.D. Erkki Valkamo M.D. 《Diseases of the colon and rectum》1995,38(6):588-593
PURPOSE: Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant cancer syndrome characterized by early onset of colorectal carcinomas (CRC). Recently, two HNPCC genes have been mapped and cloned, one in the short arm of chromosome 2 and another in the short arm of chromosome 3. There has been a major controversy about the frequency of HNPCC. The few estimates available have been based on series selected by age or series representing local area. The purpose of the present study was to design a nonselected, prospective, multicenter study, taking into account the family background and other risk factors of CRC. METHODS: The proportion of HNPCC of all (N=406) CRC cases was evaluated in a prospective multicenter study. Family history and other risk factors were investigated over a 12-month period for all new CRC patients in ten hospitals. These cases constituted 23 percent of all CRCs diagnosed in Finland during the study period. RESULTS: Three (0.7 percent) cases of verified and seven (1.7 percent) cases of suspected HNPCC were identified, following the evaluation of all families with features indicative of susceptibility to cancer. The proportion of identifiable risk factors of CRC was 5.8–7.5 percent (HNPCC, 0.7-2.4 percent; previous CRC, 3.4 percent; ulcerative colitis, 1.0 percent; familial adenomatous polyposis coli, 0.7 percent). CONCLUSION. This prospective multicenter study revealed that the frequency of hereditary colorectal cancer is lower than in some previous studies, when diagnosis is based on extensive pedigree analysis. This result with recent findings of common ancestral founding mutation in Finnish HNPCC families indicates that there may be geographic differences in the occurrence of HNPCC. However, this does not change the fact that identification of HNPCC—perhaps one of the most common inherited diseases identified in humans—has become a question of vital importance now when diagnosis of the syndrome and largescale screening of gene carriers using specific tests are on the horizon.Supported by grants from the Finnish Cancer Society, the Finnish Foundation for Gastroenterological Research, the Sigrid Juselius Foundation, and the Academy of Finland, Helsinki, Finland. 相似文献
33.
Jukka-Pekka Mecklin M.D. Pentti Sipponen M.D. Dr. Heikki J. Järvinen M.D. 《Diseases of the colon and rectum》1986,29(12):849-853
Seventy-five colorectal carcinoma patients (100 separate cancers) with verified cancer family syndrome were re-examined for
the evaluation of histologic characteristics in carcinomas and adenomatous polyps in this inherited syndrome in a comparison
with control patients with colorectal carcinoma but no hereditary background. In the cancer family syndrome group there were
significantly more mucinous carcinomas (35 to 39 percent vs. 20 percent;P<0.05–0.01), and also more poorly differentiated tumors (24 vs. 12 percent) than in the control group. The differences could
not be explained by the site or stage of the tumors or by the age or sex of the patients. Additional adenomas occurred quite
often both in cancer family syndrome patients (19 percent) and in the controls (16 percent). In the cancer family syndrome
group, however, there were more adenomas with moderate or severe dysplasia (P<0.01) and more adenomas with villous features (P<0.05) than in the control group. Mucinous histologic features in colorectal carcinoma, although not fully specific, might
be characteristic of cancer family syndrome, and thus serve as one sign in the indentification of the syndrome. The presence
of the adenoma-carcinoma sequence in cancer family syndrome also was supported, and the histologic aggressivity of the associated
adenomas might signify an accelerated advancement of this phenomenon in cancer family syndrome.
Supported by the Finnish Cancer Foundation. 相似文献
34.
Boris Klempa Tatjana Avsic-Zupanc Jan Clement Tamara K. Dzagurova Heikki Henttonen Paul Heyman Ferenc Jakab Detlev H. Kruger Piet Maes Anna Papa Evgeniy A. Tkachenko Rainer G. Ulrich Olli Vapalahti Antti Vaheri 《Archives of virology》2013,158(3):521-529
Dobrava-Belgrade virus (DOBV) is a human pathogen that has evolved in, and is hosted by, mice of several species of the genus Apodemus. We propose a subdivision of the species Dobrava-Belgrade virus into four related genotypes – Dobrava, Kurkino, Saaremaa, and Sochi – that show characteristic differences in their phylogeny, specific host reservoirs, geographical distribution, and pathogenicity for humans. 相似文献
35.
Anne S. Koponen Juha E. Peltonen Marja K. Päivinen Jyrki M. Aho Harriet J. Hägglund Arja L. Uusitalo Harri J. Lindholm Heikki O. Tikkanen 《European journal of applied physiology》2013,113(5):1181-1188
Blood O2 carrying capacity affects aerobic capacity (VO2max). Patients with type 1 diabetes have a risk for anaemia along with renal impairment, and they often have low VO2max. We investigated whether total haemoglobin mass (tHb-mass) and blood volume (BV) differ in men with type 1 diabetes (T1D, n = 12) presently without complications and in healthy men (CON, n = 23) (age-, anthropometry-, physical activity-matched), to seek an explanation for low VO2max. We determined tHb-mass, BV, haemoglobin concentration ([Hb]), and VO2max in T1D and CON. With similar (mean ± SD) [Hb] (144 vs. 145 g l?1), T1D had lower tHb-mass (10.1 ± 1.4 vs. 11.0 ± 1.1 g kg?1, P < 0.05), BV (76.8 ± 9.5 vs. 83.5 ± 8.3 ml kg?1, P < 0.05) and VO2max (35.4 ± 4.8 vs. 44.9 ± 7.5 ml kg?1 min?1, P < 0.001) than CON. VO2max correlated with tHb-mass and BV both in T1D (r = 0.71, P < 0.01 and 0.67, P < 0.05, respectively) and CON (r = 0.54, P < 0.01 and 0.66, P < 0.001, respectively), but not with [Hb]. Linear regression slopes were shallower in T1D than CON both between VO2max and tHb-mass (2.4 and 3.6 ml kg?1 min?1 vs. g kg?1, respectively) and VO2max and BV (0.3 and 0.6 ml kg?1 min?1 vs. g kg?1, respectively), indicating that T1D were unable to reach similar VO2max than CON at a given tHb-mass and BV. In conclusion, low tHb-mass and BV partly explained low VO2max in T1D and may provide early and more sensitive markers of blood O2 carrying capacity than [Hb] alone. 相似文献
36.
37.
38.
Homocysteine and carotid atherosclerosis in chronic renal failure--the confounding effect of renal function 总被引:4,自引:0,他引:4
Leskinen Y Lehtimäki T Loimaala A Huhtala H Salenius JP Oja SS Saha H 《Atherosclerosis》2004,175(2):315-323
Since total homocysteine (tHcy) level is markedly elevated in patients with chronic renal failure (CRF), it has been presented as a potential factor contributing to the high risk of cardiovascular disease (CVD) in CRF. Our aim was to examine the significance of elevated tHcy level and other cardiovascular risk factors for carotid atherosclerosis in patients with CRF. In this cross-sectional study, 135 study patients with CRF (52 +/- 11 years) included 58 patients with moderate to severe predialysis CRF, 36 dialysis patients and 41 renal transplant recipients. In addition, 58 control subjects were examined. The association of tHcy level and classic risk factors for atherosclerosis with common carotid artery intima-media thickness (IMT) or carotid artery plaque score was examined. We found no association between tHcy and carotid IMT or a high carotid plaque score in the CRF patient groups. No consistent association was found between elevated tHcy and coronary artery disease, cerebrovascular disease or peripheral arterial disease. Renal function, described as creatinine clearance, was the strongest determinant for tHcy level. Significant predictors of carotid atherosclerosis were age, duration of hypertension and elevated low-density lipoprotein cholesterol level. In conclusion, the present study shows no apparent association between tHcy level and atheromatous carotid findings in patients with CRF. However, because of the changing renal function in the course of renal disease, the strong confounding effect of renal function may not be adequately controlled for the analysis of the significance of elevated tHcy level for CVD in patients with CRF. 相似文献
39.
Possible role for mast cell-derived cathepsin G in the adverse remodelling of stenotic aortic valves 总被引:1,自引:1,他引:1
Helske Satu; Syvaranta Suvi; Kupari Markku; Lappalainen Jani; Laine Mika; Lommi Jyri; Turto Heikki; Mayranpaa Mikko; Werkkala Kalervo; Kovanen Petri T.; Lindstedt Ken A. 《European heart journal》2006,27(12):1495-1504
Aims Aortic stenosis (AS) is characterized by extensive remodellingof the valves, including infiltration of inflammatory cells,extracellular matrix degradation, and fibrosis. The molecularmechanisms behind this adverse remodelling have remained obscure.In this article, we study whether cathepsin G, an angiotensinII (Ang II)-forming elastolytic enzyme, contributes to progressionof AS. Methods and results Stenotic aortic valves (n=86) and controlvalves (n=17) were analysed for cathepsin G, transforming growthfactor-ß1 (TGF-ß1), and collagens I andIII with RTPCR and immunohistochemistry. Valvular collagen/elastinratio was quantified by histochemistry. In stenotic valves,cathepsin G was present in mast cells and showed increased expression(P<0.001), which correlated positively (P<0.001) withthe expression levels of TGF-ß1 and collagens I andIII. TGF-ß1 was also present in mast cell-rich areasand cathepsin G induced losartan-sensitive TGF-ß1expression in cultured fibroblasts. Collagen/elastin ratio wasincreased in stenotic valves (P<0.001) and correlated positivelywith smoking (P=0.02). Nicotine in cigarette smoke activatedmast cells and induced TGF-ß1 expression in culturedfibroblasts. Fragmented elastin was observed in stenotic valvescontaining activated cathepsin G-secreting mast cells and innormal valves treated with cathepsin G. Conclusion In stenotic aortic valves, mast cell-derived cathepsinG may cause adverse valve remodelling and AS progression. 相似文献