全文获取类型
收费全文 | 32678篇 |
免费 | 2238篇 |
国内免费 | 110篇 |
专业分类
耳鼻咽喉 | 258篇 |
儿科学 | 1320篇 |
妇产科学 | 974篇 |
基础医学 | 4431篇 |
口腔科学 | 404篇 |
临床医学 | 4203篇 |
内科学 | 6270篇 |
皮肤病学 | 630篇 |
神经病学 | 3486篇 |
特种医学 | 728篇 |
外科学 | 3153篇 |
综合类 | 341篇 |
一般理论 | 32篇 |
预防医学 | 3844篇 |
眼科学 | 558篇 |
药学 | 1907篇 |
中国医学 | 56篇 |
肿瘤学 | 2431篇 |
出版年
2024年 | 39篇 |
2023年 | 253篇 |
2022年 | 463篇 |
2021年 | 920篇 |
2020年 | 577篇 |
2019年 | 953篇 |
2018年 | 1024篇 |
2017年 | 716篇 |
2016年 | 827篇 |
2015年 | 860篇 |
2014年 | 1216篇 |
2013年 | 1790篇 |
2012年 | 2652篇 |
2011年 | 2707篇 |
2010年 | 1505篇 |
2009年 | 1242篇 |
2008年 | 2167篇 |
2007年 | 2340篇 |
2006年 | 2266篇 |
2005年 | 2141篇 |
2004年 | 1906篇 |
2003年 | 1762篇 |
2002年 | 1692篇 |
2001年 | 227篇 |
2000年 | 171篇 |
1999年 | 218篇 |
1998年 | 319篇 |
1997年 | 284篇 |
1996年 | 216篇 |
1995年 | 188篇 |
1994年 | 152篇 |
1993年 | 186篇 |
1992年 | 108篇 |
1991年 | 90篇 |
1990年 | 67篇 |
1989年 | 65篇 |
1988年 | 78篇 |
1987年 | 39篇 |
1986年 | 45篇 |
1985年 | 40篇 |
1984年 | 53篇 |
1983年 | 52篇 |
1982年 | 52篇 |
1981年 | 44篇 |
1980年 | 51篇 |
1979年 | 33篇 |
1978年 | 36篇 |
1977年 | 24篇 |
1975年 | 17篇 |
1973年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Gansky SA Ellison JA Rudy D Bergert N Letendre MA Nelson L Kavanagh C Walsh MM 《Journal of Athletic Training》2005,40(2):76-87
Context: Athletes in the United States are at high risk for using spit (smokeless) tobacco (ST) and incurring its associated adverse health effects.Objective: To examine whether an athletic trainer-directed ST intervention could decrease initiation and promote cessation of ST use among male collegiate baseball athletes.Design: Stratified, cluster-randomized controlled trial.Setting: Fifty-two California colleges.Patients or Other Participant(s): A total of 883 subjects in 27 intervention colleges and 702 subjects in 25 control colleges participated, as did 48 certified athletic trainers.Intervention(s): For college athletic trainers and associated dental professionals, a 3-hour video conference, and for collegiate athletes, an oral cancer screening with feedback and brief counseling during the preseason health screenings, athletic trainer support for cessation, and a peer-led educational baseball team meeting.Main Outcome Measure(s): The subjects' ST use over 1 year was assessed by self-report. At the end of the study, the certified athletic trainers were mailed a survey assessing their tobacco use and perceptions and behavior related to tobacco control in the athletic environment. We used multivariable logistic regression models for clustered responses (generalized estimating equations) to test the difference between groups in ST-use initiation and cessation and to identify significant overall predictors of noninitiation and cessation of ST use.Results: Of the 1585 athletes recruited, 1248 (78.7%) were followed up at 12 months. In addition, 48 of the 52 athletic trainers (92%) responded to the 1-year follow-up survey. The ST-use initiation (incidence) was 5.1% in intervention colleges and 8.4% in control colleges (generalized estimating equation odds ratio = 0.58, 95% confidence interval = 0.35-0.99). Predictors of ST noninitiation were low lifetime tobacco and monthly alcohol use (odds ratio = 1.98, 95% confidence interval = 1.40- 2.82) and athletic trainers' report that the baseball coach supported ST-use prevention activities (odds ratio = 1.43, 95% confidence interval = 1.11-1.83). Although at 1 year, cessation of ST use was relatively high in both groups (36%), we noted no significant difference between the groups (odd ratio = 0.94, 95% confidence interval = 0.70-1.27).Conclusions: The intervention was significantly effective in preventing incident ST use but did not significantly increase cessation beyond that seen in the control group. The latter finding is inconsistent with previous studies and may be explained by spillover of the intervention to control colleges, other anti-tobacco activity in control colleges, and/or the small sample of dependent ST users enrolled in the study. 相似文献
72.
Nicole Bruneau Frédérique Bonnet-Brilhault Marie Gomot Jean-Louis Adrien Catherine Barthélémy 《International journal of psychophysiology》2003,51(1):17-25
The purpose of the present study was to investigate the relations between late auditory evoked potentials (AEPs) recorded at temporal sites (the N1c wave or Tb) and verbal and non-verbal abilities in children with autism. The study was performed in 26 mentally retarded children with autism (AUT) aged 4-8 years (mean age +/- S.E.M. = 71 +/- 2 months; mean verbal and non-verbal developmental quotient +/- S.E.M. = 36 +/- 4 and 48 +/- 3). The stimuli used were 750 Hz tone bursts of 200 ms duration delivered binaurally at different intensity levels (50, 60, 70, 80 dB SPL) with 3-5 s interstimulus intervals. Temporal AEPs were first compared to those of a group of 16 normal children (NOR) in the same age range (mean age +/- S.E.M. = 69 +/- 3 months). We then focused on the AUT group and considered relations between temporal AEPs and the severity of disorders of verbal and non-verbal communication assessed using a behavior rating scale. AEPs recorded on left and right temporal sites were of smaller amplitude in the AUT group than in the NOR group. Increasing intensity-related amplitude was observed on both sides in NOR and only on the right side in AUT. The lack of intensity effect on the left side resulted in a particular pattern of asymmetry at the highest level of intensity (80 dB SPL) with greater N1c amplitude on the right than on the left side (the reverse was found in the NOR group). Electro-clinical correlations indicated that the greater the amplitude of the right temporal N1c responses, the higher the verbal and non-verbal communication abilities. This suggests a developmental reorganization of left-right hemisphere functions in autism, with preferential activation of the right hemisphere for functions usually allocated to the left hemisphere, particularly those involving the secondary auditory areas situated on the lateral surface of the superior temporal gyrus where the N1c/Tb wave is generated. 相似文献
73.
Pepe C Foley S Shannon J Lemiere C Olivenstein R Ernst P Ludwig MS Martin JG Hamid Q 《The Journal of allergy and clinical immunology》2005,116(3):544-549
BACKGROUND: Airway remodeling in asthma comprises a range of structural changes. Several studies have suggested an association between these changes and disease severity. The relationship between the extent of remodeling and lung function is not well defined. OBJECTIVE: We sought to contrast the structural changes in the airways of well-defined groups of subjects with severe and moderate asthma and to correlate the extent of remodeling with disease severity. METHODS: Endobronchial biopsy specimens were obtained from 15 subjects with severe and 13 subjects with moderate asthma. Epithelial integrity, cell-layer areas, subepithelial fibrosis, and the distance between epithelial and airway smooth muscle (ASM) layers were measured by means of image analysis. Collagen was identified by using Van Giesen stain, and ASM was defined by using smooth muscle alpha-actin immunostaining. Specific immunostains were performed for the evaluation of RANTES, IL-8, and eotaxin expression as markers of ASM phenotype. RESULTS: ASM area was greater in subjects with severe (0.24+/- 0.03 mm(2)) than in subjects with moderate (0.05+/- 0.01 mm(2)) asthma (P<.001). The distance between the epithelial and ASM layers was less in the severe group (0.12+/- 0.01 mm) than in the moderate group (0.24+/- 0.02, P<.001). A trend toward greater subepithelial fibrosis in subjects with severe asthma did not reach statistical significance. IL-8 and eotaxin expression, but not RANTES expression, were increased in the ASM of subjects with severe asthma compared with in subjects with moderate asthma. CONCLUSION: Smooth muscle alteration is the key structural change that distinguishes severe from moderate asthma, and phenotypic change in ASM might contribute to the difficulty in obtaining adequate control in some subjects with severe asthma. 相似文献
74.
Evaluation of a microsphere-based flow cytometric assay for diagnosis of celiac disease 总被引:2,自引:0,他引:2
Yiannaki EE Zintzaras E Analatos A Theodoridou C Dalekos GN Germenis AE 《Journal of immunoassay & immunochemistry》2004,25(4):345-357
The multiplexed particle-based flow cytometric technology proposes a new approach for the diagnosis of autoimmune diseases combining the advantages of conventional methods with the ability to quantitatively determine multiple autoantibodies in the same sample, simultaneously and rapidly. Recently, a commercial kit (FIDIS Celiac, Biomedical Diagnostics, Mane la Vallé, France) was introduced for the simultaneous detection of IgA anti-tissue transglutaminase (anti-tTG), IgG, and IgA anti-gliadin antibodies (AGA). This study was undertaken to evaluate and compare the FIDIS Celiac kit with standardized commercial ELISAs (QUANTA Lite, INOVA Diagnostics Inc., San Diego, CA). A disease group consisted of 21 samples from untreated patients with biopsy confirmed celiac disease (CD), and two control groups of historical sera (207 from regular blood donors and 181 from chronically infected hepatitis patients) were studied. All control sera were negative for IgA anti-endomysial antibodies (EmA) and had an IgA concentration above the lower normal limit. Concerning the reproducibility, intra- and inter-assay coefficients of variation (CVs) ranging between 2% and 12%, and between 3% and 21%, respectively, were observed. Regarding the diagnostic quality, each assay was compared to the disease diagnosis using the McNemar test and the kappa (K) parameter, while ROC analysis was applied. Generally, the performance of FIDIS assay was proved almost equally adequate to that of ELISA in the detection of IgA anti-tTG antibodies, IgA and IgG AGA. However, the performance of FIDIS assay was found surmounting that of ELISA among hepatitis patients, possibly due to the avoidance of debris and unbound cross contaminants and, hence, the "noise" of such materials in samples under analysis. Taking our results together with the simplicity and the high throughput of FIDIS assay, its overall performance in the diagnosis of CD seems better than that of ELISA. 相似文献
75.
A mutation in the gene TNFRSF11B encoding osteoprotegerin causes an idiopathic hyperphosphatasia phenotype 总被引:5,自引:0,他引:5
76.
Morice P Leblanc E Rey A Baron M Querleu D Blanchot J Duvillard P Lhommé C Castaigne D Classe JM Bonnier P;GCCLCC SFOG 《Human reproduction (Oxford, England)》2005,20(5):1379-1385
BACKGROUND: Results of conservative management of epithelial ovarian cancer (EOC) remain controversial in the literature. The aim of this study was to assess the clinical outcomes and fertility following fertility-sparing surgical management of EOC in a retrospective multicentre study. METHODS: A multicentre retrospective study was performed by members of two French groups. Six inclusion criteria were defined: (i) Histological review by the same pathologist; (ii) age < or =40 years; (iii) conservative management; (iv) complete peritoneal staging; (v) delivery of a platinum-based chemotherapy in stage > or = IC; and (vi) follow-up >1 year. RESULTS: Thirty-four patients fulfilled the inclusion criteria: 30 had stage IA disease; three had stage IC and one had stage IIA. Eleven patients had recurrence: 10 patients had invasive disease and one had borderline recurrence. Among 10 patients with invasive recurrence, initial stage and grade were: stage IA G1, n = 1; stage IA G2, n = 4; stage IA G3, n = 1; and stage> or = IC, n = 4. All patients with stage > IA had recurrence. Ten pregnancies were observed in nine patients. CONCLUSION: Conservative surgery for patients with EOC could be considered in young patients with stage IA G1 disease. This procedure should not be performed in patients with FIGO stage > IA. 相似文献
77.
Adoptive immunotherapy for posttransplantation viral infections. 总被引:1,自引:0,他引:1
Catherine M Bollard Ingrid Kuehnle Ann Leen Cliona M Rooney Helen E Heslop 《Biology of blood and marrow transplantation》2004,10(3):143-155
Viral diseases are a major cause of morbidity and mortality after hemopoietic stem cell transplantation. Because viral complications in these patients are clearly associated with the lack of recovery of virus-specific cellular immune responses, reconstitution of the host with in vitro expanded cytotoxic T lymphocytes is a potential approach to prevent and treat these diseases. Initial clinical studies of cytomegalovirus and Epstein-Barr virus in human stem cell transplant patients have shown that adoptively transferred donor-derived virus-specific T cells may restore protective immunity and control established infections. Preclinical studies are evaluating this approach for other viruses while strategies for generating T cells specific for multiple viruses to provide broader protection are being evaluated in clinical trials. The use of genetically modified T cells or the use of newer suicide genes may result in improved safety and efficacy. 相似文献
78.
McCuskey RS Ekataksin W LeBouton AV Nishida J McCuskey MK McDonnell D Williams C Bethea NW Dvorak B Koldovsky O 《The anatomical record. Part A, Discoveries in molecular, cellular, and evolutionary biology》2003,275(1):1019-1030
The development of hepatic microvascular heterogeneity after birth, and its temporal relationship to the development of parenchymal cell plates have received little attention. As a result, the morphogenesis of some of the parameters contributing to this heterogeneity in suckling and weaned rats was studied as a function of time between postpartum days 4 and 30 using in vivo light microscopic, electron microscopic, and immunocytochemical methods. During the early suckling period, the sinusoid network is highly anastomotic, with little evidence of zonation, and the parenchymal cell plates contain multiple cells and are irregularly arranged throughout the lobule. Sinusoidal endothelial fenestration is sparse at 4 days, but phagocytic Kupffer cell (KC) function already exists and exhibits zonal heterogeneity, with more cells located in the periportal zone. With increasing age, endothelial fenestrae increase and organize as sieve plates. Widened centrilobular radial sinusoids form through a loss ("drop-out") of intersinusoidal sinusoids (ISS). Concomitantly, the associated cell plates straighten and become one cell thick. Hepatocyte DNA synthesis and mitosis are higher in the periportal zone, which retains thickened cell plates and anastomotic sinusoids. The centrilobular sinusoids may widen to accommodate the increased volume of blood that results from the loss of ISS as well as the increased numbers of periportal sinusoids containing flow that feed these vessels. KC phagocytic activity increases during the suckling period concomitant with an increase of gut-derived endotoxin in the portal blood, which suggests that the KCs may be releasing mediators that affect sinusoid diameter, blood flow, endothelial fenestration, and perhaps parenchymal growth either directly or through the stimulation of growth factors. 相似文献
79.
80.
Reevaluation of a genetic model for the development of exostosis in hereditary multiple exostosis 总被引:3,自引:0,他引:3
EXT1 and EXT2 are genes that have been shown to cause hereditary multiple exostosis (HME), a syndrome marked by the formation of bony growths juxtaposed to the growth plate. These genes are members of a growing family of proteins with glycosyltransferase activity required for the synthesis of heparan sulfate chains. This protein activity is predicted to play a role in the expression of proteoglycans on the cell surface and in the extracellular matrix. We and others have previously suggested that a two-hit mutational model applies to the development of an exostosis where a germline mutation coupled with a somatic mutation results in the loss of EXT1 or EXT2 function and subsequent tumor formation. We report the direct sequencing and loss of heterozygosity (LOH) analysis of 12 exostoses from 10 HME families, 4 solitary exostoses, and their corresponding constitutional DNA. Of the 16 exostoses screened, we find only one solitary case in which two somatic mutations, a deletion and an LOH, are present. This provides limited support for the two-hit hypothesis involving the EXT1 and EXT2 genes for the development of an exostosis. Alternative models are developed based on the functional significance of EXT proteins in heparan sulfate biosynthesis. 相似文献