全文获取类型
收费全文 | 656篇 |
免费 | 35篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 25篇 |
妇产科学 | 8篇 |
基础医学 | 64篇 |
口腔科学 | 31篇 |
临床医学 | 41篇 |
内科学 | 149篇 |
皮肤病学 | 6篇 |
神经病学 | 56篇 |
特种医学 | 100篇 |
外科学 | 67篇 |
综合类 | 5篇 |
预防医学 | 39篇 |
眼科学 | 1篇 |
药学 | 37篇 |
肿瘤学 | 40篇 |
出版年
2020年 | 7篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 13篇 |
2016年 | 5篇 |
2015年 | 13篇 |
2014年 | 13篇 |
2013年 | 28篇 |
2012年 | 24篇 |
2011年 | 18篇 |
2010年 | 19篇 |
2009年 | 15篇 |
2008年 | 23篇 |
2007年 | 21篇 |
2006年 | 22篇 |
2005年 | 28篇 |
2004年 | 12篇 |
2003年 | 13篇 |
2002年 | 16篇 |
2001年 | 16篇 |
2000年 | 11篇 |
1999年 | 25篇 |
1998年 | 19篇 |
1997年 | 17篇 |
1996年 | 19篇 |
1995年 | 18篇 |
1994年 | 16篇 |
1993年 | 17篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 25篇 |
1988年 | 19篇 |
1987年 | 17篇 |
1986年 | 12篇 |
1985年 | 20篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 10篇 |
1979年 | 14篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 13篇 |
1974年 | 6篇 |
1973年 | 4篇 |
1970年 | 4篇 |
1966年 | 4篇 |
排序方式: 共有697条查询结果,搜索用时 15 毫秒
1.
2.
Diagnosis of scaphoid fractures:A prospective multicenter study of 1,052 patients with 160 fractures
Bo Munk Johnny Fr kj r Claus Falck Larsen Hans Gad Johannsen Lars Lundager Rasmussen Annette Edal Lilla Demeney Rasmussen 《Acta orthopaedica》1995,66(4):359-360
In a prospective multicenter study of 1,052 patients with clinical signs of a scaphoid fracture, mammo-graphic films and fine intensifying screens were used at the radiographic examination. 5 standardized projections including 3 special projections focused on the scaphoid were taken. 150 fractures were diagnosed at the first examination but in 10 cases the fracture was first diagnosed at a second radiographic examination after 10-14 days.
The second examination still seems mandatory despite the use of high quality radiographs with optimal spatial resolution and contrast, and the value of supplementary special projections. 相似文献
The second examination still seems mandatory despite the use of high quality radiographs with optimal spatial resolution and contrast, and the value of supplementary special projections. 相似文献
3.
Structural modification of receptor-binding technetium-99m complexes in order to improve brain uptake 总被引:2,自引:0,他引:2
Bernd Johannsen Ralf Berger Peter Brust Hans-Juergen Pietzsch Matthias Scheunemann Sepp Seifert Hartmut Spies Rosemarie Syhre 《European journal of nuclear medicine and molecular imaging》1997,24(3):316-319
Low brain uptake is a generally accepted problem in developing technetium-99m brain receptor imaging agents. For a class of potential 5-HT2A receptorbinding agents we tried to improve the original low brain uptake of 0.4% injected dose (ID) in rats 5 min p.i. by modifying the lipophilic properties of the molecules. Because of the presence of a protonable nitrogen, which according to the pK
a value leads to ionization of the molecule at blood pH, the pK
a value was considered to be the parameter most suitable for adjustment of lipophilicity. Insertion of ether-oxygen in the molecule of five candidates lowers the apparent pK
a value from 10.0 to 8.3 and dramatically increases the brain uptake to 1.3% ID at 5 min. The direct relationship between brain uptake and apparent pK
a cannot be simply explained by the increase in the pK
a-governed proportion of the neutral species. 相似文献
4.
U Johannsen G W Dominok 《Zentralblatt für allgemeine Pathologie und pathologische Anatomie》1985,130(2):117-124
Leg thickness in piglets was found to be an autosomal recessive defect resulting in a primary developmental disturbance of the periosteal and connective components of the soft tissues of the fore- and, less frequently, hindlegs. Histologically there is periosteal thickening with periosteal proliferation of woven bone spiculae and also of myxoid elements of the soft tissue between bone and skin. Similar entities are not known in the human literature. Analogies with human hereditary congenital elephantiasis and pes equinovarus are incorrect. 相似文献
5.
Levente Kaps Ferenc Obl Jr. Mark R. Opp Lars Johannsen James M. Krueger 《Physiology & behavior》1991,50(6):1241-1244
Cholecystokinin (CCK) reduces food intake and promotes non-rapid-eye-movement sleep (NREMS) in rats. The purpose of present experiments was to determine if CCK is somnogenic in rabbits; another species in which CCK suppresses feeding. White New Zealand rabbits were treated intracerebroventricularly (ICV; 0.05, 0.5 and 2 μg) or intraperitoneally (IP; 2.5, 10 and 40 μg/kg) with CCK or saline, and sleep-wake activity and brain temperature (Tbr) were recorded for 6 h. Injections of 10 and 40 μg/kg CCK IP elicited a decrease in wakefulness and an increase in NREMS during the first hour postinjection. The hypnogenic effects were accompanied by a decrease in Tbr. After the IP injection of a lower dose (2.5 μg/kg) a slight, nonsignificant increase in NREMS during the first hour postinjection was followed by a decrease in NREMS. ICV injections of CCK had relatively small inhibitory effects on sleep. We conclude that circulating, hormone CCK might be a hypnogenic signal with a peripheral site of action. 相似文献
6.
7.
8.
Deeg HJ; Storb R; Thomas ED; Flournoy N; Kennedy MS; Banaji M; Appelbaum FR; Bensinger WI; Buckner CD; Clift RA 《Blood》1985,65(6):1325-1334
Seventy-five patients, 13 to 49 years of age, with acute nonlymphoblastic leukemia in first remission were treated with cyclophosphamide, fractionated total body irradiation, and marrow transplantation from an HLA-identical sibling and randomized to receive either cyclosporine (CSP) (n = 36) or methotrexate (MTX) (n = 39) as prophylaxis for graft-v-host disease (GVHD). All patients engrafted, and 22 who were given CSP and 21 who were given MTX, are alive at 20 to 47 (median, 35) months (P = .5). Engraftment as assessed by granulocyte recovery (P less than .0005) and platelet transfusion requirement (P = .01) was faster in patients on CSP. Twelve patients (33%) on CSP and 22 (56%) on MTX developed acute GVHD of grades II through IV (P = .07) and 15 of 30 on CSP and 14 of 32 on MTX that were at risk developed chronic GVHD. The most frequent causes of death were interstitial pneumonitis and marrow relapse of leukemia, which occurred with similar frequency in both groups. Beneficial effects observed in patients on CSP included less severe mucositis and shorter duration of hospitalization; adverse effects included renal function impairment and hypertension. These data confirm that CSP is a useful immunosuppressant in patients undergoing marrow transplantation but fail to show a significant improvement in survival as compared with the standard regimen of MTX. 相似文献
9.
Clinical spirometry in normal Bantu 总被引:7,自引:0,他引:7
10.
Velocity fields and turbulent stresses downstream of biological and mechanical aortic valve prostheses implanted in pigs 总被引:4,自引:0,他引:4
J M Hasenkam E M Pedersen J H Ostergaard H Nygaard P K Paulsen G Johannsen B A Schurizek 《Cardiovascular research》1988,22(7):472-483
Since detailed knowledge about velocity fields downstream of heart valve prostheses obtained from in vitro studies has not been followed up by similar detailed studies in vivo a pig model for acute velocity field studies downstream of aortic valve prostheses was established. Two mechanical and two bioprosthetic valves were studied and a dynamic three dimensional visualisation of velocity fields one diameter downstream performed under different haemodynamic conditions in a total of 22 pigs. The Ionescu-Shiley pericardial valve had velocity fields very similar to the normal native porcine aortic valve. The Edwards-Carpentier porcine valve caused a jet type flow, and the valve design of the St Jude Medical and Bj?rk-Shiley Monostrut valves was reflected in the velocity profile. Normalised (mean(SEM] systolic Reynolds normal stresses in the total cross sectional area were: native porcine 15(1.5) Nm-2; St Jude Medical 24(3.4) Nm-2; Bj?rk-Shiley Monostrut 25(1.6) Nm-2; Edwards-Carpentier Supra-annular 51(6.6) Nm-2; Ionescu-Shiley Pericardial 19(2.0) Nm-2. Reynolds normal stresses were higher in areas of rapidly changing or constantly high velocity gradients. 相似文献