全文获取类型
收费全文 | 1830篇 |
免费 | 181篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 121篇 |
妇产科学 | 20篇 |
基础医学 | 260篇 |
口腔科学 | 40篇 |
临床医学 | 216篇 |
内科学 | 424篇 |
皮肤病学 | 18篇 |
神经病学 | 94篇 |
特种医学 | 225篇 |
外科学 | 285篇 |
综合类 | 37篇 |
预防医学 | 76篇 |
眼科学 | 5篇 |
药学 | 60篇 |
中国医学 | 5篇 |
肿瘤学 | 121篇 |
出版年
2022年 | 8篇 |
2021年 | 24篇 |
2020年 | 17篇 |
2019年 | 17篇 |
2018年 | 47篇 |
2017年 | 50篇 |
2016年 | 53篇 |
2015年 | 43篇 |
2014年 | 55篇 |
2013年 | 85篇 |
2012年 | 74篇 |
2011年 | 75篇 |
2010年 | 84篇 |
2009年 | 79篇 |
2008年 | 60篇 |
2007年 | 70篇 |
2006年 | 50篇 |
2005年 | 50篇 |
2004年 | 46篇 |
2003年 | 47篇 |
2002年 | 55篇 |
2001年 | 48篇 |
2000年 | 48篇 |
1999年 | 51篇 |
1998年 | 73篇 |
1997年 | 70篇 |
1996年 | 68篇 |
1995年 | 57篇 |
1994年 | 33篇 |
1993年 | 45篇 |
1992年 | 38篇 |
1991年 | 31篇 |
1990年 | 36篇 |
1989年 | 24篇 |
1988年 | 33篇 |
1987年 | 29篇 |
1986年 | 21篇 |
1985年 | 19篇 |
1984年 | 20篇 |
1983年 | 25篇 |
1982年 | 9篇 |
1981年 | 20篇 |
1980年 | 10篇 |
1977年 | 14篇 |
1976年 | 13篇 |
1975年 | 11篇 |
1974年 | 9篇 |
1973年 | 7篇 |
1971年 | 10篇 |
1922年 | 7篇 |
排序方式: 共有2022条查询结果,搜索用时 31 毫秒
61.
Rashid Ghaznawi Maarten HT Zwartbol Nicolaas PA Zuithoff Jeroen de Bresser Jeroen Hendrikse Mirjam I Geerlings 《Journal of cerebral blood flow and metabolism》2021,41(6):1229
Global cerebral hypoperfusion may be involved in the aetiology of brain atrophy; however, long-term longitudinal studies on this relationship are lacking. We examined whether reduced cerebral blood flow was associated with greater progression of brain atrophy. Data of 1165 patients (61 ± 10 years) from the SMART-MR study, a prospective cohort study of patients with arterial disease, were used of whom 689 participated after 4 years and 297 again after 12 years. Attrition was substantial. Total brain volume and total cerebral blood flow were obtained from magnetic resonance imaging scans and expressed as brain parenchymal fraction (BPF) and parenchymal cerebral blood flow (pCBF). Mean decrease in BPF per year was 0.22% total intracranial volume (95% CI: –0.23 to –0.21). Mean decrease in pCBF per year was 0.24 ml/min per 100 ml brain volume (95% CI: –0.29 to –0.20). Using linear mixed models, lower pCBF at baseline was associated with a greater decrease in BPF over time (p = 0.01). Lower baseline BPF, however, was not associated with a greater decrease in pCBF (p = 0.43). These findings indicate that reduced cerebral blood flow is associated with greater progression of brain atrophy and provide further support for a role of cerebral blood flow in the process of neurodegeneration. 相似文献
62.
Hui Wu Daniel Haag Thomas Muley Arne Warth Marc Zapatka Grischa Toedt Armin Pscherer Meinhard Hahn Ralf J. Rieker David L. Wachter Michael Meister Philipp Schnabel Karin Müller‐Decker Michael A. Rogers Hans Hoffmann Peter Lichter 《Genes, chromosomes & cancer》2013,52(3):250-264
Invasion is a critical step in lung tumor progression. The interaction between tumor cells and their surroundings may play an important role in tumor invasion and metastasis. To better understand the mechanisms of tumor invasion and tumor–microenvironment interactions in lung tumors, total RNA was isolated from the inner tumor, tumor invasion front, adjacent lung, and distant normal lung tissue from 17 patients with primary squamous cell lung carcinoma using punch‐aided laser capture microdissection. Messenger RNA expression profiles were obtained by microarray analysis, and microRNA profiles were generated from eight of these samples using TaqMan Low Density Arrays. Statistical analysis of the expression data showed extensive changes in gene expression in the inner tumor and tumor front compared with the normal lung and adjacent lung tissue. Only a few genes were differentially expressed between tumor front and the inner tumor. Several genes were validated by immunohistochemistry. Evaluation of the microRNA data revealed zonal expression differences in nearly a fourth of the microRNAs analyzed. Validation of selected microRNAs by in situ hybridization demonstrated strong expression of hsa‐miR‐196a in the inner tumor; moderate expression of hsa‐miR‐224 in the inner tumor and tumor front, and strong expression of hsa‐miR‐650 in the adjacent lung tissue. Pathway analysis placed the majority of genes differentially expressed between tumor and nontumor cells in intrinsic processes associated with inflammation and extrinsic processes related to lymphocyte physiology. Genes differentially expressed between the inner tumor and the adjacent lung/normal lung tissue affected pathways of arachidonic acid metabolism and eicosanoid signaling. © 2012 Wiley Periodicals, Inc. 相似文献
63.
Arnt V. Kristen Katrin Ackermann Sebastian Buss Lorenz Lehmann Philipp A. Schnabel Armin Haunstetter Hugo A. Katus Stefan E. Hardt 《Cardiovascular pathology》2013,22(4):280-286
SummaryThe detailed molecular mechanisms following activation of apoptosis in ischemia-reperfusion injury are unknown. This study using different transgenic mouse models provided first evidence that apoptosis in myocardial ischemia-reperfusion injury is rather linked to the mitochondrial pathway than to death receptor pathway.IntroductionThere is a wealth of evidence for activation of apoptosis in ischemia-reperfusion injury. However, the understanding of detailed molecular mechanism is lacking.MethodsThe extent of myocardial infarction after ligation of the left anterior descending artery in mice carrying different transgenes for inhibition of either the intrinsic or the extrinsic or a combination of both apoptotic cascades was evaluated. The extent of myocardial damage was assessed by echocardiographic determination of left ventricular (LV) ejection fraction, LV hemodynamics, troponin T, and histology. The rate of apoptosis was analyzed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and caspase-3 staining.ResultsHighest perioperative rate of death was observed in the dominant-negative form of a truncated Fas-associated death domain (FADD-DN) group. Infarction size by 2,3,5-triphenyltetrazolium chloride (TTC) staining was smaller in the Bcl-2, but not in the other groups as compared to wild-type mice. This was accompanied by lower troponin T values in Bcl-2 transgenic mice as compared to the all other groups. Troponin T correlated well with macroscopic extent of myocardial infarction by TTC staining. A lower decline of LV ejection fraction was seen in the Bcl-2 as compared to wild-type or FADD-DN mice. A smaller number of TUNEL- and caspase-3-positive myocyte nuclei were observed in the Bcl-2 and FADD-DN group as compared to wild-type mice.ConclusionsWe provide first evidence for protective effects on the myocardium in a transgenic mouse model of myocardial ischemia-reperfusion due to inhibition of the Bcl-2, but not the FADD pathway despite that reduced apoptotic cells were observed in both groups as compared to wild-type mice. 相似文献
64.
Fc gamma receptor II (CD32) on malignant B cells influences modulation induced by anti-CD19 monoclonal antibody 总被引:1,自引:1,他引:1
Vervoordeldonk SF; Merle PA; van Leeuwen EF; van der Schoot CE; von dem Borne AE; Slaper-Cortenbach IC 《Blood》1994,83(6):1632-1639
Antigenic modulation is one of many factors determining the effectiveness of monoclonal antibody (MoAb)-mediated therapy. To select the isotype of a CD19 MoAb most suitable for radioimmunotherapy of patients with B-cell malignancies, we studied the influence of MoAb isotype on modulation, after binding of the MoAb to different cell-line cells. The CD19-IgG1 MoAb was found to induce modulation of CD19 antigens on Daudi cell line cells more rapidly than did its IgG2a switch variant. We provide evidence that this difference in modulation rate is caused by the expression of Fc gamma receptor II (Fc gamma RII) on these cells. Experiments aimed at elucidating the mechanism of Fc gamma RII involvement in modulation induction by CD19-IgG1 showed that Fc gamma RII did not comodulate with CD19 MoAbs. However, cocrosslinking of CD19 and Fc gamma RII with CD19-IgG1 MoAb resulted in enhanced calcium mobilization in Daudi cells. This increased signal induction accompanies the enhanced capping and subsequent modulation of CD19 antigens. Because Fc gamma RII is expressed in varying densities on malignant B cells in all differentiation stages, our results have implications for the MoAb isotype most suitable for use in MoAb-based therapy of patients with B-cell malignancies. 相似文献
65.
A sensitive and precise radioreceptor assay for determining plasma levels of human factor VIII/von Willebrand's factor (FVIII/vWF) has been developed by taking advantage of the FVIII/vWF receptor sites on human platelets. Paraformaldehyde-fixed platelets, which were processed and then stored, retained FVIII/vWF binding activity and therefore could be used as a convenient source of receptors. The human plasma samples to be tested were initially filtered on 4% agarose columns to concentrate the FVIII/vWF protein in the void volume and to remove the factor(s) that interferes with the assay. The percent recovery of FVIII/vWF in the pooled eluent was measured by the recovery of added trace 125I-FVIII/vWF. The coefficients of intra- and interassay variation were 6% and 10%, respectively. The plasma FVIII/vWF concentrations determined by the assay for pooled normal plasma, hemophilia A plasma, and plasmas from two patients with von Willebrand's disease were 16.3 +/- 0.5, 52.6 +/- 1.5, 6.8 +/- 0.8, and 3.2 +/- 0.2 microgram/ml, respectively. The range of plasma FVIII/vWF concentrations varied between 8.3 microgram/ml and 24.9 microgram/ml for 10 normal adults. The plasma FVIII/vWF concentrations determined by the radioreceptor assay correlated well with levels measured by the ristocetin-induced platelet aggregation method, thus demonstrating the functional relevancy of the radioreceptor assay for plasma FVIII/vWF. 相似文献
66.
67.
Long‐term efficacy of a 0.07% cetylpyridinium chloride mouth rinse in relation to plaque and gingivitis: a 6‐month randomized,vehicle‐controlled clinical trial
下载免费PDF全文
![点击此处可从《International journal of dental hygiene》网站下载免费的PDF全文](/ch/ext_images/free.gif)
68.
Hightower A Kinkade C Nguku PM Anyangu A Mutonga D Omolo J Njenga MK Feikin DR Schnabel D Ombok M Breiman RF 《The American journal of tropical medicine and hygiene》2012,86(2):373-380
We estimated Rift Valley fever (RVF) incidence as a function of geological, geographical, and climatological factors during the 2006-2007 RVF epidemic in Kenya. Location information was obtained for 214 of 340 (63%) confirmed and probable RVF cases that occurred during an outbreak from November 1, 2006 to February 28, 2007. Locations with subtypes of solonetz, calcisols, solonchaks, and planosols soil types were highly associated with RVF occurrence during the outbreak period. Increased rainfall and higher greenness measures before the outbreak were associated with increased risk. RVF was more likely to occur on plains, in densely bushed areas, at lower elevations, and in the Somalia acacia ecological zone. Cases occurred in three spatial temporal clusters that differed by the date of associated rainfall, soil type, and land usage. 相似文献
69.
Becker N Motsch E Gross ML Eigentopf A Heussel CP Dienemann H Schnabel PA Pilz L Eichinger M Optazaite DE Puderbach M Tremper J Delorme S 《Journal of cancer research and clinical oncology》2012,138(9):1475-1486
Purpose
Low-dose multislice-CT (MSCT) detects many early-stage lung cancers with good prognosis, but whether it decreases lung cancer mortality and at which costs is yet insufficiently explored. Scope of the present study is to examine within a common European effort whether MSCT screening is capable to reduce the lung cancer mortality by at least 20?% and at which amount of undesired side effects this could be achieved.Methods
Overall 4,052 heavy smoking men and women were recruited by a population-based approach and randomized into a screening arm with five annual MSCT screens and an initial quit-smoking counseling, and a control arm with initial quit-smoking counseling and five annual questionnaire inquiries.Results
In the first screening round, 2,029 participants received a MSCT providing 1,488 negative and 540 suspicious screens with early recalls (early recall rate 26.6?%) leading to 31 biopsies (biopsy rate 1.5?%) and 22 confirmed lung cancers (detection rate 1.1?%). Among the lung cancers, 15 were adenocarcinomas, 3 squamous cell carcinomas, one small-cell lung cancer, and 3 others, whereby 18 were in clinical stage I, one in stage II, and 3 in stage III. One interval cancer occurred.Conclusions
The indicated performance indicators fit into the range observed in comparable trials. The study continues finalizing the second screening round and for the first participants even the last screening round. The unresolved issue of the precise amount of side effects and the high early recall rate precludes currently the recommendation of MSCT as screening tool for lung cancer. 相似文献70.
BO Motayo PA Akinduti FA Adeyakinu PO Okerentugba JC Nwanze CC Onoh HC Innocent-Adiele IO Okonko 《African health sciences》2013,13(4):1091-1097