全文获取类型
收费全文 | 1242篇 |
免费 | 72篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 24篇 |
妇产科学 | 15篇 |
基础医学 | 156篇 |
口腔科学 | 192篇 |
临床医学 | 130篇 |
内科学 | 200篇 |
皮肤病学 | 16篇 |
神经病学 | 80篇 |
特种医学 | 198篇 |
外科学 | 130篇 |
综合类 | 9篇 |
预防医学 | 54篇 |
眼科学 | 1篇 |
药学 | 80篇 |
肿瘤学 | 42篇 |
出版年
2023年 | 7篇 |
2021年 | 12篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 15篇 |
2016年 | 31篇 |
2015年 | 26篇 |
2014年 | 37篇 |
2013年 | 50篇 |
2012年 | 44篇 |
2011年 | 64篇 |
2010年 | 49篇 |
2009年 | 38篇 |
2008年 | 59篇 |
2007年 | 68篇 |
2006年 | 60篇 |
2005年 | 54篇 |
2004年 | 50篇 |
2003年 | 55篇 |
2002年 | 53篇 |
2001年 | 40篇 |
2000年 | 34篇 |
1999年 | 45篇 |
1998年 | 43篇 |
1997年 | 27篇 |
1996年 | 17篇 |
1995年 | 21篇 |
1994年 | 11篇 |
1993年 | 15篇 |
1992年 | 13篇 |
1991年 | 23篇 |
1990年 | 12篇 |
1989年 | 27篇 |
1988年 | 19篇 |
1987年 | 18篇 |
1986年 | 25篇 |
1985年 | 28篇 |
1984年 | 15篇 |
1983年 | 17篇 |
1982年 | 12篇 |
1981年 | 3篇 |
1980年 | 10篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 13篇 |
1976年 | 5篇 |
1975年 | 9篇 |
1974年 | 3篇 |
1970年 | 2篇 |
排序方式: 共有1335条查询结果,搜索用时 62 毫秒
1.
2.
Intratemporal vascular tumors: detection with CT and MR imaging 总被引:1,自引:0,他引:1
Lo WW; Shelton C; Waluch V; Solti-Bohman LG; Carberry JN; Brackmann DE; Wade CT 《Radiology》1989,171(2):445-448
The diagnostic contributions of computed tomography (CT) and magnetic resonance (MR) imaging were compared in 12 patients with benign intratemporal vascular tumors (hemangioma or vascular malformation). The tumors included six in the internal acoustic canal and six in the geniculate ganglion region. Clinical and histologic correlations were made. Two of the six patients with tumors in the internal acoustic canal underwent CT, and both required gas cisternography to show the tumor. Five patients in that group underwent MR imaging, and all five studies showed the tumor. All six patients with geniculate ganglion tumors underwent CT. Results in one study were questionable, and five showed the tumor. Five patients in this group underwent MR imaging, but the MR findings were positive in only two cases. MR imaging should therefore be performed before CT in the evaluation of facial nerve dysfunction, as it demonstrated all tumors in the internal acoustic canal and some in the geniculate ganglion region. If MR findings are negative, CT should then be performed to rule out a possible geniculate ganglion lesion. 相似文献
3.
32nd Annual Meeting of the Scandinavian Society for Psychopharmacology Copenhagen, Denmark April 10–12, 1991 Abstracts 相似文献
4.
K.A. Eaton F.M. Rimini E. Zak D.J. Brookman L.M.A. Hopkins P. J. Carmell LG. Yates C. A. Morrice B.A. Lall H. N. Newman 《Journal of clinical periodontology》1997,24(3):189-197
Abstract Several previous studies have evaluated the effects of 0.12% chlorhexidine digluconate (ChD) mouthrinses on plaque and gingival inflammation. However, previously, none have been based in general dental practices. The aim of this study was to evaluate the potential to conduct controlled periodontal clinical trials in co-operation with general dental practitioners (gdps). The project took place in 5 general dental practices in the South of England. 121 healthy subjects (24 at 4 sites and 25 at the 5th). aged 18-65 years, mean 35 ± 12) years participated in a double-blind, randomised study during which they received full mouth assessments for plaque and gingival bleeding at baseline, 6 and 12 weeks. 60 subjects were randomly asigned to use the 0.12% ChD mouth wash and 6i the placebo. The assessments were carried out by 5 gpds, who had previously achieved inter-examiner κ scores of 0.78–0.85 (mean 0.81) for the plaque index (PlI), and of 0.73–0.94 (mean 0.87) for a modified gingival index (mGI), and who maintained κ scores of 0.51–0.90 for PII and of 0.73–1.00 for mGI during the 12 months required to complete the study. 98 subjects (48 ChD and 50 placebo) completed the study. Even though the baseline levels of plaque and gingivitis were low, by week 12, mean whole mouth piaque score of the ChD mouthwash users had fallen from 1.33 at baseline to 0.96 and was significantly lower (p < 0.001) than for the placebo users, 1.31 at baseline to 1.13. Whole-mouth gingival bleeding score fell from 0.56 to 0.42 in the ChD mouthwash group but was unchanged (0.54–0.55) in the placebo group. A subsidiary data analysis which considered the effects at sites indicated that within these overall differences, the ChD users experienced almost 2× the reduction from plaque score 2 at baseline at proximal molar sites over a 12-week period (50.6% ChD versus 27.6% placebo). It was concluded that 0.12% ChD mouthwash reduced plaque accumulation fay 28% and gingival inflammation by 25% over a 12–week period, that it is feasible for a group of gdps to maintain high levels of inter–examiner consistency in the use of PlI and mGI, that it is also feasible to carry out such a multicentre study in general dental practice, and that the use of mean mouth scores per subject to analyse the effects of mouthrinses may well mask variations in response throughout the mouth. 相似文献
5.
Catarina Gonzalez da Silva Karl Magnus Petersson Luís Faísca Martin Ingvar Alexandra Reis 《Journal of clinical and experimental neuropsychology》2004,26(2):266-277
Semantic verbal fluency tasks are commonly used in neuropsychological assessment. Investigations of the influence of level of literacy have not yielded consistent results in the literature. This prompted us to investigate the ecological relevance of task specifics, in particular, the choice of semantic criteria used. Two groups of literate and illiterate subjects were compared on two verbal fluency tasks using different semantic criteria. The performance on a food criterion (supermarket fluency task), considered more ecologically relevant for the two literacy groups, and an animal criterion (animal fluency task) were compared. The data were analysed using both quantitative and qualitative measures. The quantitative analysis indicated that the two literacy groups performed equally well on the supermarket fluency task. In contrast, results differed significantly during the animal fluency task. The qualitative analyses indicated differences between groups related to the strategies used, especially with respect to the animal fluency task. The overall results suggest that there is not a substantial difference between literate and illiterate subjects related to the fundamental workings of semantic memory. However, there is indication that the content of semantic memory reflects differences in shared cultural background--in other words, formal education--, as indicated by the significant interaction between level of literacy and semantic criterion. 相似文献
6.
Nitric oxide-donating properties of mesoionic 3-aryl substituted oxatriazole-5-imine derivatives. 总被引:2,自引:2,他引:0 下载免费PDF全文
H. Kankaanranta E. Rydell A. S. Petersson P. Holm E. Moilanen T. Corell G. Karup P. Vuorinen S. B. Pedersen A. Wennmalm T. Mets-Ketel 《British journal of pharmacology》1996,117(3):401-406
1. The nitric oxide (NO)-releasing properties of two new mesoionic 3-aryl substituted oxatriazole-5-imine derivatives (GEA 3162 and GEA 3175) were characterized and compared with the known NO-donors 3-morpholino-sydnonimine (SIN-1) and S-nitroso-N-acetylpenicillamine (SNAP). 2. GEA 3162, GEA 3175, SIN-1 and SNAP inhibited adenosine 5'-diphosphate-induced platelet aggregation (IC50 values 0.18, 0.39, 3.73 and 2.12 microM, respectively). All four compounds induced a dose-dependent and more than 4 fold increase in cyclic GMP in platelets. The increase in cyclic GMP concentration was potentiated more than 1.5 fold by a phosphodiesterase inhibitor, zaprinast (10 microM) and inhibited 38-97% by oxyhaemoglobin (10-45 microM). 3. All of the four compounds studied converted oxyhaemoglobin to methaemoglobin and formed a paramagnetic NO-haemoglobin complex. All but GEA 3175 formed nitrite and nitrate in phosphate buffer. During a 40 min incubation, GEA 3162, SIN-1 and SNAP (100 microM) produced 50-70 microM NO2- + NO3- as determined by high performance liquid chromatography. The release of NO and NO2 by GEA 3175 was increased 140 fold in the presence of human plasma (0.14 and 19.7 ppb in the absence and presence of 1% human plasma, respectively) as analyzed by ozone chemiluminescence. 4. The results suggest that the mesoionic 3-aryl substituted oxatriazole-5-imine derivatives GEA 3162 and GEA 3175 as well as SIN-1 and SNAP release nitric oxide. 相似文献
7.
LG Dortmund 《MedR Medizinrecht》2007,25(8):493-494
Abstrakt Vergibt ein behandelnder Arzt eine Laboruntersuchung an einen externen Laborarzt, kommt entweder direkt ein Vertragsverh?ltnis
zwischen dem Laborarzt und dem Patienten zustande oder der Patient haftet dem Laborarzt aus den Grunds?tzen der Gesch?ftsführung
ohne Auftrag. 相似文献
8.
9.
Relation between tobacco use and urinary excretion of thromboxane A2 and prostacyclin metabolites in young men 总被引:1,自引:0,他引:1
A Wennmalm G Benthin E F Granstr?m L Persson A S Petersson S Winell 《Circulation》1991,83(5):1698-1704
BACKGROUND. Cigarette smoking is a risk factor for cardiovascular disease. The present study addressed the effect of tobacco use on the formation of two eicosanoids, thromboxane A2 and prostacyclin, which have been implicated in both acute and chronic cardiovascular disorders. METHODS AND RESULTS. In 577 randomly sampled 18-19-year-old men, the urinary excretion of the 2,3-dinor metabolites of thromboxane A2 and prostacyclin (Tx-M and PGI-M, respectively) was analyzed and related to the subjects' self-reported use of tobacco. Sixty-five percent of the subjects used no tobacco, 7.5% were cigarette smokers, 22% used wet (oral) snuff, and the rest reported a mixed use of tobacco. The urinary excretion of Tx-M was higher (p less than 0.001) in cigarette smokers than in those not using tobacco (180 versus 128 pg/mg creatinine) and was correlated (r = 0.35, p less than 0.05) with the daily cigarette consumption. Snuff users had no increase in their urinary excretion of Tx-M, despite urinary cotinine levels comparable to those in the cigarette smokers (1,210 and 1,560 ng/ml, respectively). The excretion of PGI-M did not differ between non-tobacco users, cigarette smokers, and snuff users. CONCLUSIONS. We conclude that cigarette smoking, but not the use of snuff, facilitates the formation of thromboxane A2. We propose that such an increased formation reflects platelet activation in the absence of vascular injury and that it may be of significance for the subsequent development of cardiovascular disease. 相似文献
10.
Clinical History, Skin Prick Test and RAST in the Diagnosis of Birch and Timothy Pollinosis 总被引:2,自引:2,他引:0
The diagnostic efficacy of clinical history (CH), skin prick test (SPT) and RAST was estimated in relation to nasal and conjunctival provocation tests (NPT, CPT) in 69 patients with seasonal rhinoconjunctivitis. The extracts used were freeze-dried, and biologically standardized birch and timothy allergen preparations matched to the extracts on Phadebas RAST discs. Based on single determinations the sensitivity, specificity and predictive values were calculated. There were highly significant (P less than 0.001) correlations between all parameters: NPT, CPT, CH, SPT and RAST. For birch the combination of SPT and RAST made the PTs superfluous as both sensitivity and specificity then reached 100%. With timothy the sensitivity was 97% and with the addition of CH 100%. However, the specificity was only 79% through combining CH, SPT and RAST. The present study using the same standardized allergen preparation in all tests showed a good correlation between indirect test results and provocation tests. 相似文献