全文获取类型
收费全文 | 82204篇 |
免费 | 7083篇 |
国内免费 | 3504篇 |
专业分类
耳鼻咽喉 | 655篇 |
儿科学 | 1539篇 |
妇产科学 | 1500篇 |
基础医学 | 10348篇 |
口腔科学 | 1479篇 |
临床医学 | 9217篇 |
内科学 | 14057篇 |
皮肤病学 | 1193篇 |
神经病学 | 5141篇 |
特种医学 | 3037篇 |
外国民族医学 | 34篇 |
外科学 | 9258篇 |
综合类 | 9182篇 |
现状与发展 | 15篇 |
一般理论 | 43篇 |
预防医学 | 6198篇 |
眼科学 | 1846篇 |
药学 | 7750篇 |
52篇 | |
中国医学 | 3116篇 |
肿瘤学 | 7131篇 |
出版年
2024年 | 201篇 |
2023年 | 1029篇 |
2022年 | 2421篇 |
2021年 | 3491篇 |
2020年 | 2486篇 |
2019年 | 2494篇 |
2018年 | 2713篇 |
2017年 | 2332篇 |
2016年 | 2398篇 |
2015年 | 3181篇 |
2014年 | 3989篇 |
2013年 | 4348篇 |
2012年 | 6117篇 |
2011年 | 6385篇 |
2010年 | 4011篇 |
2009年 | 3353篇 |
2008年 | 4828篇 |
2007年 | 4827篇 |
2006年 | 4457篇 |
2005年 | 4191篇 |
2004年 | 3476篇 |
2003年 | 3316篇 |
2002年 | 2963篇 |
2001年 | 1797篇 |
2000年 | 1678篇 |
1999年 | 1558篇 |
1998年 | 956篇 |
1997年 | 932篇 |
1996年 | 752篇 |
1995年 | 653篇 |
1994年 | 566篇 |
1993年 | 413篇 |
1992年 | 560篇 |
1991年 | 479篇 |
1990年 | 438篇 |
1989年 | 391篇 |
1988年 | 300篇 |
1987年 | 303篇 |
1986年 | 250篇 |
1985年 | 214篇 |
1984年 | 171篇 |
1983年 | 130篇 |
1982年 | 130篇 |
1981年 | 126篇 |
1980年 | 84篇 |
1979年 | 109篇 |
1978年 | 71篇 |
1976年 | 58篇 |
1974年 | 69篇 |
1973年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Biallelic deletions in INK4 in cutaneous melanoma are common and associated with decreased survival. 总被引:5,自引:0,他引:5
Eva Grafstr?m Suzanne Egyházi Ulrik Ringborg Johan Hansson Anton Platz 《Clinical cancer research》2005,11(8):2991-2997
PURPOSE: Both the retinoblastoma and p53 pathways are often genetically altered in human cancers and their complex regulation is in part mediated by the three gene products p16, p14(ARF), and p15 of the INK4 locus on chromosome 9p21. Partial or complete biallelic deletions of the INK4 locus have been recognized in a variety of malignant tumors, including malignant melanoma. We have in the present study measured the frequency of INK4 deletions in a large number of melanoma metastases and determined their association with clinicopathologic variables and survival data. EXPERIMENTAL DESIGN: Quantitative real-time PCR, as well as fluorescence-based fragment analysis, has been used to perform measurements of the relative allelic concentrations of the INK4 genes in 112 human melanoma tumor samples from 86 patients. RESULTS: Thirty-eight of 86 melanoma patients (44%) had metastases with biallelic losses in INK4. Ten of 20 patients with multiple metastases showed similar deletion patterns in all analyzed tumors. There was no significant association between any of the clinicopathologic variables and loss of INK4. However, loss of INK4 had an adverse effect on median survival from time of diagnosis. Patients with tumors with diploid INK4 had a median survival of 142 months, whereas those with monoallelic or biallelic loss in INK4 had a median survival of only 47 months (P = 0.006). CONCLUSIONS: Our results point to homozygous deletions in the INK4 region as being one of the most common genetic alterations in malignant cutaneous melanoma. INK4 deletions are associated with an adverse prognosis. 相似文献
992.
K Kian Ang Jonathan Harris Adam S Garden Andy Trotti Christopher U Jones Luis Carrascosa Jonathan D Cheng Sharon S Spencer Arlene Forastiere Randal S Weber 《Journal of clinical oncology》2005,23(13):3008-3015
PURPOSE: To investigate the feasibility of combining concomitant boost accelerated radiation regimen (AFX-C) with cisplatin and to assess its toxicity and the relapse pattern and survival in patients with advanced head and neck carcinoma (HNC). PATIENTS AND METHODS: Between April and November of 2000, 84 patients with stage III to IV HNC who met the eligibility criteria were enrolled; 76 of these patients were analyzable. Radiation consisted of 72 Gy in 42 fractions over 6 weeks (daily for 3.5 weeks, then twice a day for 2.5 weeks). Cisplatin dose was 100 mg/m(2) on days 1 and 22. Tumor and clinical status were assessed, and acute late toxicities were graded. RESULTS: Sixty-five patients (86%) received both radiation and chemotherapy per protocol or with minor variations. The estimated 2-year locoregional relapse and distant metastasis rates were 34.7% and 16.1%, respectively. The estimated 2-year overall survival and disease-free survival rates were 71.6% and 53.5%, respectively. Three patients (4%) died of complications, 19 patients (25%) had acute grade 4 toxicity, and 49 patients (64%) had acute grade 3 toxicity. The 2-year cumulative incidence of late grade 3 to 5 toxicities was 51.3%. CONCLUSION: These data showed that it was feasible to combine AFX-C with cisplatin. The compliance to therapy was high, and the locoregional control and survival rates achieved compared favorably with AFX-C alone or other concurrent chemoradiation regimens tested by the Radiation Therapy Oncology Group. A phase III trial comparing AFX-C plus cisplatin against standard radiation plus cisplatin is ongoing to determine whether the use of AFX-C in the concurrent chemoradiation setting further improves outcome. 相似文献
993.
The association of XRCC1 haplotypes and chromosomal damage levels in peripheral blood lymphocyte among coke-oven workers. 总被引:1,自引:0,他引:1
Shuguang Leng Juan Cheng Linyuan Zhang Yong Niu Yufei Dai Zufei Pan Bin Li Fengsheng He Yuxin Zheng 《Cancer epidemiology, biomarkers & prevention》2005,14(5):1295-1301
Theoretically, a haplotype has a higher level of heterozygosity than individual single nucleotide polymorphism (SNP) and the association study based on the haplotype may have an increased power for detecting disease associations compared with SNP-based analysis. In this study, we investigated the effects of four haplotype-tagging SNPs (htSNP) and the inferred haplotype pairs of the X-ray cross-complementing group 1 (XRCC1) gene on chromosome damage detected by the cytokinesis-block micronucleus assay. The study included 141 coke-oven workers with exposure to a high level of polycyclic aromatic hydrocarbons and 66 nonexposed controls. The frequencies of total MN and MNed cells were borderline associated with the Arg(194)Trp polymorphism (P = 0.053 and P = 0.050, respectively) but not associated with the Arg(280)His, Arg(399)Gln and Gln(632)Gln polymorphisms among coke-oven workers. Five haplotypes, including CGGG, TGGG, CAGG, CGAG, and CGGA, were inferred based on the four htSNPs of XRCC1 gene. The haplotype CGGG was associated with the decreased frequencies of total MN and MNed cells, and the haplotypes TGGG and CGAG were associated with the increased frequencies of total MN and MNed cells with adjustment for covariates among coke-oven workers. This study showed that the haplotypes derived from htSNPs in the XRCC1 gene were more likely than single SNPs to correlate with the polycyclic aromatic hydrocarbon-induced chromosome damage among coke-oven workers. 相似文献
994.
Carlos Camps Herrero Pilar Bayo Zaera Rafael Sirera Pérez Eva Sancho Salvador Ana Blasco Cordellat María José Safont Aguilera 《Clinical & translational oncology》2005,7(3):122-126
INTRODUCTION: Presence of circulating DNA in the serum of patients with cancer makes detection of tumour-specific genetic alterations feasible. OBJECTIVE: To study serum DNA concentration in patients diagnosed as having advanced Non-Small Cell Lung Cancer (NSCLC) and to evaluate its relationship with age, histology, stage, response, time-to-progression (TTP), and survival. METHODS: Serum DNA from 78 patients was purified and spectrophotometrically quantified. RESULTS: No significant correlations were found between serum DNA concentration and age, histology, response and survival. There was a significant correlation with respect to stage (IIIB = 408.75 ng/ml; IV = 478.74 ng/ml; p = 0.02). When patients were grouped according to DNA concentration, significant correlation with TTP was found; establishing a cut-off point at 500 ng/ml ([DNA] < 500 ng/ml TTP = 7.25 months, 95%CI: 3.5-5.25; [DNA ] > or = 500 ng/ml TTP = 4.25 months, 95%CI: 2-6.5; p = 0.05). CONCLUSIONS: Using the present method, DNA concentration quantification appears to be simple, but with certain deficiencies due to inter-sample variability and low specificity. This is because total DNA concentration is measured without distinguishing as to whether it is tumour-related. We suggest that there is a correlation between DNA concentration and prognosis which enables an analysis of the natural history of the disease. 相似文献
995.
This study provides a closed form, analytical expression for the thermal dose delivered by a single heating pulse. The solution is derived using the effective cooling method and the non-linear Sapareto-Dewey equation to determine the thermal dose delivered by the time-temperature history of a treatment. The analytical solutions are used to determine the optimal treatment conditions, i.e. those that exactly deliver the desired thermal dose at a specified time. For purposes of illustration, this study focuses on a 'conservative' clinical approach in which the desired thermal dose is delivered at the end of the 'cool down' period. The analytical results show that, after a clinical strategy has been chosen (e.g. conservative, aggressive or intermediate), the user can only specify two free variables for such an optimal treatment. Results are presented which suggest that a practical approach would be to specify both (1) the desired thermal dose to be delivered to the target (the clinically relevant outcome) and (2) the peak temperature to be reached (a measurable, clinically useful, patient dependent response variable that can be employed in feedback control systems); and then determine the associated, optimal heating magnitude and duration that need to be used to reach that dose and temperature. The results also reveal that, with a given patient condition and power deposition distribution (together specifying an effective cooling time constant for the treatment) and a specified thermal dose, there is a maximum allowable peak temperature that, if exceeded, will result in 'over-dosing' the heated tissue. The results also show that avoiding such non-optimal 'over-dosing' will be difficult in most high temperature therapies since, when high temperatures are produced in tissues, the temperature decay must be very fast in order to avoid over-dosing during the cooling period. Such rapid cooling can only occur if short effective cooling time constants are present-either as a result of large tissue blood flows in the patient or due to large conduction effects induced by the use of highly localized power deposition sources. 相似文献
996.
目的构建婴儿双歧杆菌/胞嘧啶脱氨酶靶向性基因治疗系统。方法 PCR 扩增 CD 基因,EcoR Ⅰ,BamH Ⅰ对 CD 基因和 pGEX-1LamdaT 质粒同时进行双酶切,获得4.9 kb、1.3 kh 两个 DNA 片段。T4 DNA 连接酶连接这两个片段构建重组的CD/pGEX-1LamdaT 质粒,然后用电穿孔法将重组质粒转染婴儿双歧杆菌。从阳性转染的婴儿双歧杆菌中提取重组质粒,双酶切后检测切取片段长度,采用 Sanger 双脱氧链终止法对提取的重组质粒中的插入片段进行测序。结果从阳性转染的婴儿双歧杆菌中获得了6.2 kb大小的重组质粒,该质粒经双酶切后,得到了4.9 kb 和1.3 kb 两个长度的片段,其长度分别与 pGEX-1LambdaT 及 CD 基因的长度相同。测序结果显示,提取的重组质粒中插入的基因片段全长及核苷酸序列与 CD 基因完全相同。结论外源性 CD 基因被准确插入 pGEX-1LambdaT 质粒并转入婴儿双歧杆菌中,婴儿双歧杆菌/胞嘧啶脱氨酶靶向性基因治疗系统被成功构建。 相似文献
997.
Solitary fibrous tumors of the pleura: clinical, radiological, surgical and pathological evaluation. 总被引:2,自引:0,他引:2
S C Lee C Tzao S M Ou H H Hsu C P Yu Y L Cheng 《European journal of surgical oncology》2005,31(1):84-87
AIMS: To report a clinicopathological series of cases of solitary fibrous tumor of the pleura from Taiwan. METHODS: Clinical data was collected from a review of medical records and telephone interviewing for follow-up. RESULTS: Eight patients, three men and five women aging from 34 to 71 years, underwent tumor resection and were followed in a period from 7 months to 13.5 years. Six patients underwent standard thoracotomy and two had VATS for tumor excision. Tumors were pathologically benign in seven patients and malignant in one. Patients were all alive with no evidence of tumor recurrence at the time of this report. CONCLUSIONS: One should always consider SFTPs as potentially malignant tumors. Complete resection remains the mainstay of cure. Standard thoracotomy should always be considered when a high suspicion of malignancy is raised, whereas VATS may be a preferred approach for smaller tumors. 相似文献
998.
Steven P Treon Mark Hansen Andrew R Branagan Sigitas Verselis Christos Emmanouilides Eva Kimby Stanley R Frankel Nikolaos Touroutoglou Barry Turnbull Kenneth C Anderson David G Maloney Edward A Fox 《Journal of clinical oncology》2005,23(3):474-481
PURPOSE: Rituximab is an important therapeutic for Waldenstrom's macroglobulinemia (WM). Polymorphisms in FcgammaRIIIA (CD16) receptor expression modulate human immunoglobulin G1 binding and antibody-dependent cell-mediated cytotoxicity, and may therefore influence responses to rituximab. PATIENTS AND METHODS: Sequence analysis of the entire coding region of FcgammaRIIIA was undertaken in 58 patients with WM whose outcomes after rituximab were known. RESULTS: Variations in five codons of FcgammaRIIIA were identified. Two were commonly observed (FcgammaRIIIA-48 and FcgammaRIIIA-158) and predicted for amino acid polymorphisms at FcgammaRIIIA-48: leucine/leucine (L/L), leucine/arginine (L/R), and leucine/histidine (L/H). Polymorphisms at FcgammaRIIIA-158 were phenylalanine/phenylalanine (F/F), phenylalanine/valine (F/V), and valine/valine (V/V). A clear linkage between these polymorphisms was detected and all patients with FcgammaRIIIA-158F/F were always FcgammaRIIIA-48L/L, and patients with either FcgammaRIIIA-L/R or -L/H always expressed at least one valine at FcgammaRIIIA-158 (P < or = .001). The response trend was higher for patients with FcgammaRIIIA-48L/H (38.5%) versus -48L/R (25.0%) and LL (22.0%), and was significantly higher for patients with FcgammaRIIIA-158V/V (40.0%) and -V/F (35%) versus -158F/F (9.0%; P = .030). Responses for patients with FcgammaRIIIA-48L/L were higher when at least one valine was present at FcgammaRIIIA-158 (P = .057), thereby supporting a primary role for FcgammaRIIIA-158 polymorphisms in predicting rituximab responses. With a median follow-up of 13 months, no significant differences in the median time to progression and progression-free survival were observed when patients were grouped according to their FcgammaRIIIA-48 and -158 polymorphisms. CONCLUSION: The results of these studies therefore support a predictive role for FcgammaRIIIA-158 polymorphisms and responses to rituximab in WM. 相似文献
999.
陈益昀主任中医师是全国第二、三批中医药专家学术经验继承指导老师,临床悬壶五十余载,治学严谨,注重实际。几十年的临床实践加之深厚扎实的理论功底,尤其能够结合现代医学知识,使其在治疗疾病,立法用药上独树一帜。笔者有幸随师学习,获益匪浅,兹将陈老师运用中西医结合治疗输卵管阻塞性不孕症的经验总结介绍如下: 相似文献
1000.
IGF-I, IGFBP-3 and breast cancer in young women: a pooled re-analysis of three prospective studies. 总被引:2,自引:0,他引:2
Sabina Rinaldi Paolo Toniolo Paola Muti Eva Lundin Anne Zeleniuch-Jacquotte Alan Arslan Andrea Micheli Per Lenner Laure Dossus Vittorio Krogh Roy E Shore Karen L Koenig Elio Riboli P?r Stattin Franco Berrino G?ran Hallmans Annekatrin Lukanova Rudolf Kaaks 《European journal of cancer prevention》2005,14(6):493-496
Prospective cohort studies on breast cancer risk among premenopausal women and insulin-like growth factor I (IGF-I) concentrations have so far included only few cases, and have shown inconsistent relative risk estimates. We pooled 220 cases of breast cancer diagnosed before age 50, and 434 control subjects, from three prospective studies in New York (USA), Ume? (Northern Sweden) and Milan (Italy), and we measured IGF-I and insulin-like growth factor binding protein 3 (IGFBP-3) with common enzyme-linked immunosorbent assays. Overall, IGF-I and IGFBP-3 measurements obtained by the common method showed a positive but not significant relationship with breast cancer risk (odds ratios (ORs) 0.90 [95% confidence intervals (95% CI) 0.50-1.62], 1.63 [0.89-2.97], 1.46 [0.78-2.73] and 1.41 [0.75-2.63] for quintiles of IGF-I, and ORs 0.98 [0.54-1.75], 1.06 [0.59-1.91], 1.04 [0.58-1.87] and 1.77 [0.97-3.24] for quintiles of IGFBP-3). Our results give only moderate support for an association of blood IGF-I with breast cancer risk in young women. 相似文献