全文获取类型
收费全文 | 6352篇 |
免费 | 352篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 30篇 |
儿科学 | 130篇 |
妇产科学 | 35篇 |
基础医学 | 840篇 |
口腔科学 | 181篇 |
临床医学 | 529篇 |
内科学 | 1027篇 |
皮肤病学 | 158篇 |
神经病学 | 537篇 |
特种医学 | 267篇 |
外科学 | 858篇 |
综合类 | 21篇 |
预防医学 | 1220篇 |
眼科学 | 145篇 |
药学 | 378篇 |
中国医学 | 4篇 |
肿瘤学 | 352篇 |
出版年
2022年 | 26篇 |
2021年 | 103篇 |
2020年 | 49篇 |
2019年 | 63篇 |
2018年 | 90篇 |
2017年 | 86篇 |
2016年 | 107篇 |
2015年 | 126篇 |
2014年 | 147篇 |
2013年 | 200篇 |
2012年 | 347篇 |
2011年 | 363篇 |
2010年 | 209篇 |
2009年 | 237篇 |
2008年 | 327篇 |
2007年 | 348篇 |
2006年 | 298篇 |
2005年 | 289篇 |
2004年 | 299篇 |
2003年 | 286篇 |
2002年 | 230篇 |
2001年 | 107篇 |
2000年 | 132篇 |
1999年 | 102篇 |
1998年 | 58篇 |
1997年 | 63篇 |
1996年 | 106篇 |
1995年 | 222篇 |
1994年 | 214篇 |
1993年 | 183篇 |
1992年 | 210篇 |
1991年 | 191篇 |
1990年 | 130篇 |
1989年 | 56篇 |
1988年 | 48篇 |
1987年 | 64篇 |
1986年 | 60篇 |
1985年 | 45篇 |
1984年 | 36篇 |
1983年 | 32篇 |
1982年 | 21篇 |
1981年 | 24篇 |
1980年 | 24篇 |
1979年 | 30篇 |
1978年 | 27篇 |
1977年 | 26篇 |
1975年 | 25篇 |
1974年 | 19篇 |
1973年 | 25篇 |
1971年 | 18篇 |
排序方式: 共有6712条查询结果,搜索用时 31 毫秒
11.
Florian M Vogt Gerald Antoch Patrick Veit Lutz S Freudenberg Nina Blechschmid Olaf Diersch Andreas Bockisch J?rg Barkhausen Hilmar Kuehl 《Journal of nuclear medicine》2007,48(11):1836-1844
Rimlike contrast enhancement on morphologic imaging and increased tracer uptake on (18)F-FDG PET in the periphery of the necrosis can hamper differentiation of residual tumor from regenerative tissue after radiofrequency ablation of liver lesions. This study used MRI, CT, ultrasound, and (18)F-FDG PET/CT to assess the typical appearance of lesions in nontumorous animal liver tissue after radiofrequency ablation. METHODS: Lesions were created by radiofrequency ablation of normal liver parenchyma in 21 minipigs. Follow-up was performed by 3 contrast-enhanced morphologic modalities-MRI, CT, and ultrasound-and by (18)F-FDG PET/CT immediately, 3 and 10 d, and 1, 2, 3, and 6 mo after radiofrequency ablation. Images were evaluated qualitatively for areas of increased enhancement and regions of elevated tracer uptake. Furthermore, all images were assessed quantitatively by determination of ratios comparing enhancement/tracer uptake in the periphery of the necrosis with enhancement/tracer uptake in normal liver parenchyma. Imaging findings were compared with histopathology findings. RESULTS: Immediately after radiofrequency ablation, no increase in (18)F-FDG uptake was visible, whereas elevated enhancement was noticed in the periphery of the necrosis on all morphologic imaging procedures. At further follow-up, an area of rimlike increase in (18)F-FDG uptake surrounding the necrosis was detected on PET/CT. The rimlike pattern of increased enhancement in the arterial phase was present for all liver lesions on CT, MRI, and ultrasound, especially between day 3 and month 1 after the radiofrequency ablation. Both elevated glucose metabolism and enhancement persisted for 6 mo postinterventionally. Histologic examination showed a hemorrhagic border converting into a regeneration capsule. CONCLUSION: If performed immediately after radiofrequency ablation, (18)F-FDG PET/CT probably has benefits over those of morphologic imaging procedures when assessing liver tissue for residual tumor. Later follow-up may be hampered by visualization of peripheral hyperperfusion and tissue regeneration. Further studies on a patient population are essential. 相似文献
12.
Summary A review is made of the current management strategies of abscesses in basal ganglia and thalamus, based on a review of the literature and three of our own cases. Clinical picture, aetiology, diagnostic, surgical treatment and outcome are discussed. Stereotactic abscess puncture in combination with temporary drainage and rinsing of the abscess cavity in combination with systemic medication of antibiotics has become the management of choice with satisfactory results. 相似文献
13.
Lutz Liefeldt Martin Buhl Britta Schweickert Elisabeth Engelmann Orhan Sezer Peter Laschinski Lothar Preuschof Hans-H Neumayer 《Nephrology, dialysis, transplantation》2002,17(10):1840-1842
14.
In 196 patients suffering from disease of the cephalic salivary glands and in 57 healthy controls the concentration of albumin in parotid and submandibular saliva was measured by the immunodiffusion technique. To summarize the results, albumin seems to be a reliable marker of inflammations of the salivary glands even in the early stages and is therefore recommended for the primary diagnostic and the follow-up of acute and chronic inflammatory conditions of the major cephalic salivary glands. In combination with the evaluation of the flow rate, other sialochemic parameters like phosphohexose isomerase and kallikrein activity, B-mode sonography and fine needle aspiration biopsy the frequency of x-ray examination of the radiosensitive salivary glands may be reduced. 相似文献
15.
Hans Rommelspacher Lutz G. Schmidt Torsten May 《Alcoholism, clinical and experimental research》1991,15(3):553-559
Based on the hypothesis that condensation products of neurotransmitters with aldehydes are involved in the pathogenesis of alcoholism, aromatic beta-carbolines (norharman and harman) were measured in the blood plasma of alcoholics and nonalcoholics. The identity of the extracted compounds was confirmed by various elution conditions of the high performance liquid chromatography (HPLC), newly developed radioreceptor assays, and the mass spectrum of norharman. The levels of norharman and harman in nonalcoholics were unchanged after a load with ethanol (1 g/kg body weight). The norharman levels of the alcoholics were significantly higher than that of the nonalcoholic controls (99.5 +/- 26.6 pg/ml vs. 26.9 +/- 10.7 pg/ml; p less than 0.001) and did not change significantly during a 3-week detoxication period. In the subgroup of alcoholics with delirium or hallucinosis, a slight increase of norharman during detoxication could be detected while in alcoholics with vegetative withdrawal symptoms norharman levels dropped slightly over time (p = 0.07). No difference was found with respect to harman between nonalcoholics and alcoholics. These results suggest disturbed regulatory processes in the formation and/or metabolism of norharman in alcoholics. Further investigations are needed to reveal a possible marker function of norharman in alcoholic patients. 相似文献
16.
Dr. Lutz Lindemann-Sperfeld Klaus-Dieter Rudolf Michael Steen Ivan Marintschev Wieland Otto 《Trauma und Berufskrankheit》2003,5(2):198-207
Complex injuries of the foot are often overlooked, especially in the multiple injured patient, and they then lead to major loss of function. When the mechanism of injury suggests involvement of the foot, a clinical examination of the lower extremities should be included in the primary diagnostic procedures implemented in the multiply injured patient, followed by radiological examination once the patient's condition is stable. The condition of the soft tissues is of decisive importance in the prognosis of complex foot injuries, regardless of whether the damage to the foot is one component of a polytrauma or an isolated injury, which can also be life threatening. The diagnostic examinations selected should be adapted to the severity of the injuries in the particular multiply injured patient. Successful therapy involves stable internal fixation of injuries to bones and joints, though the external fixation options should be considered in the first instance, and carefully selected methods of temporary and definitive soft tissue reconstruction. The aim of treatment is the best possible reconstruction of the foot as a functional weight-bearing unit with intact soft tissue cover and a natural form. Good results can be achieved when there is close interdisciplinary cooperation between trauma (orthopedic) and plastic surgeons. Patient with severe injuries of this kind should be transferred to a trauma center as the first step toward this end. 相似文献
17.
Lutz Fritsche Klemens Budde Hans-Hellmut Neumayer 《Nephrology, dialysis, transplantation》2003,18(3):621-2; author reply 622
Sir, The paper by Zeier and Ritz in the April 2002 issue of NDT [1]is a good reminder of the importance of evaluation and selectionof kidney transplant candidates. Also, this paper clearly demonstratesthe persisting lack of clinical evidence in this field, whichhas considerable impact on large numbers of end-stage renaldisease patients. We have previously demonstrated the unexplained variations inthe evaluation 相似文献
18.
Mammaglobin remains a useful marker for the detection of breast cancer cells in peripheral blood. 总被引:1,自引:0,他引:1
Otto Zach Dieter Lutz 《Journal of clinical oncology》2005,23(13):3160; author reply 3160-3160; author reply 3161
19.
20.
Nitrosation of dietary components has been combined with the 4-(para-nitrobenzyl)pyridine (NBP) colorimetric test for screening alkylating agents and with the Ames test for the detection of mutagenic activity. This allowed the investigation of short-lived nitrosation products of dietary components which generate electrophilic degradation products requiring no metabolic activation (natural amino acids and some derivatives, ureas, guanidines, primary alkyl and aryl amines). In a first system, precursor, nitrous acid and NBP were present simultaneously. All amino acids tested, except glutamic acid and glutamine, gave positive results. The reactivities spanned more than three orders of magnitude, with the aromatic amino acids and methionine the most active; two primary amines, tryptamine and histamine, were also strongly reactive. All guanidines tested, except the amino acid arginine, gave negative results. A second system consisted of two phases: NBP was added only after destruction of residual nitrite and adjustment of the pH to neutrality. This system was useful for the study of ureas, which are stable in acid but not in neutral media. The range of responses covered more than two orders of magnitude. Most amino acids and primary amines also gave positive results, but could be assessed only after analysing the kinetics of the competing reactions and choosing appropriate reaction times. In a third system, Salmonella typhimurium strain TA100 replaced NBP. Representatives of the class of amino acids, ureas, the primary amine tryptamine, and aniline became highly mutagenic upon nitrosation. Methylguanidine was only weakly mutagenic under the present assay conditions. The results indicate that further studies with unstable nitrosation products of dietary components are required to understand more thoroughly the role of endogenous nitrosation in gastric cancer. 相似文献