全文获取类型
收费全文 | 34063篇 |
免费 | 2305篇 |
国内免费 | 1397篇 |
专业分类
耳鼻咽喉 | 252篇 |
儿科学 | 362篇 |
妇产科学 | 830篇 |
基础医学 | 7643篇 |
口腔科学 | 525篇 |
临床医学 | 2208篇 |
内科学 | 5167篇 |
皮肤病学 | 540篇 |
神经病学 | 1127篇 |
特种医学 | 1421篇 |
外国民族医学 | 3篇 |
外科学 | 1565篇 |
综合类 | 4256篇 |
现状与发展 | 5篇 |
预防医学 | 2574篇 |
眼科学 | 244篇 |
药学 | 3383篇 |
3篇 | |
中国医学 | 770篇 |
肿瘤学 | 4887篇 |
出版年
2024年 | 44篇 |
2023年 | 394篇 |
2022年 | 753篇 |
2021年 | 944篇 |
2020年 | 867篇 |
2019年 | 821篇 |
2018年 | 739篇 |
2017年 | 904篇 |
2016年 | 1040篇 |
2015年 | 1212篇 |
2014年 | 1698篇 |
2013年 | 2274篇 |
2012年 | 1568篇 |
2011年 | 1903篇 |
2010年 | 1554篇 |
2009年 | 1669篇 |
2008年 | 1648篇 |
2007年 | 1702篇 |
2006年 | 1663篇 |
2005年 | 1582篇 |
2004年 | 1438篇 |
2003年 | 1265篇 |
2002年 | 1138篇 |
2001年 | 1028篇 |
2000年 | 902篇 |
1999年 | 741篇 |
1998年 | 717篇 |
1997年 | 636篇 |
1996年 | 591篇 |
1995年 | 565篇 |
1994年 | 594篇 |
1993年 | 416篇 |
1992年 | 433篇 |
1991年 | 326篇 |
1990年 | 305篇 |
1989年 | 252篇 |
1988年 | 224篇 |
1987年 | 142篇 |
1986年 | 155篇 |
1985年 | 198篇 |
1984年 | 162篇 |
1983年 | 65篇 |
1982年 | 85篇 |
1981年 | 93篇 |
1980年 | 90篇 |
1979年 | 66篇 |
1978年 | 56篇 |
1977年 | 34篇 |
1976年 | 35篇 |
1975年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
为探讨流式细胞术对涎腺腺样囊性癌的诊断和预后估计的价值,对41例腺样囊性癌行流式细胞术分析。结果,平均DNA指数为1.179,S期细胞比例为29.49%,细胞增殖指数为42.67%,均明显高于正常组织。异倍体检出率为70.73%。随着肿瘤的增大和恶性程度的增加,其异倍体率、DNA指数和S期细胞比例值也相应增加。流式细胞术为涎腺腺样囊性癌的病理诊断和确定恶性程度提供了有效的辅助诊断措施,但尚不能判断预后。 相似文献
82.
83.
荧光定量聚合酶链反应在尖锐湿疣诊断中的应用 总被引:3,自引:0,他引:3
目的 探讨荧光定量聚合酶链反应 (FQ - PCR)对尖锐湿疣 (CA )的诊断价值。方法 FQ- PCR检测病理确诊的 CA患者 36份标本和健康人 84份标本 ;FQ- PCR及病理诊断同期检测临床送检病例 2 73份标本 ,并做诊断性试验评价。结果 36例病理确诊的 CA患者 HPV6和 HPV11的 DNA FQ- PCR全部阳性 ,平均拷贝数为 1.0× 10 7± 1.0× 10 2 / m l;84例健康人 FQ- PCR全部阴性 ,平均拷贝数为 3× 10± 2× 10 / ml。 FQ- PCR与病理诊断符合率为 10 0 % ,CA患者与健康人拷贝数的差异有显著性 (P<0 .0 5 )。FQ- PCR与病理诊断对比得出 :灵敏度为 10 0 % ,特异度为 92 % ,误诊率为 0 .0 8,漏诊率为 0 ,准确度为 98.9% ,阳性预测值为 98.8% ,阴性预测值为 10 0 % ,阳性似然比为 12 .5 ,阴性似然比为 0。结论 FQ - PCR能准确定量 ,灵敏度高 ,特异性强 ,快速 ,简便 ,可作为尖锐湿疣早期诊断的指标 相似文献
84.
Kohsuke Sasaki Daniel Pinkel Masato Tsukahara Ichiro Murano Joe W Gray 《Pathology international》1994,44(2):145-150
A human chromosomal translocation t(8;9) was detected using two-color fluorescence in situ hybridization with probes capable of staining the entire lengths of each of these chromosomes. The chromosome 8 probe was labeled with biotin and detected with Texas red, while the chromosome 9 probe was labeled with AAF and detected with FITC . In normal metaphase spreads, two metaphases from the proband, two red, one green and one part red and part green derivative chromosome were seen. The bicolor chromosome corresponded to translocation of a chromosome 8 segment to the distal part of the q region of one chromosome 9, as originally indicated by banding analysis. In interphase nuclei of the proband, four domains with bright fluorescence were recognized in many nuclei. Two were red, one was green, and the fourth had portions of both colors, indicating the presence of the translocation. 相似文献
85.
Summary. The utility of the 5-bromodeoxy-uridine (BrdUrd) labelling technique for the quantitative analysis of spermatogenic deoxyribonucleic acid (DNA) synthesis was investigated in the rat. Rat testicles were labelled by a single intraperitoneal injection of 100 mg kg−1 of BrdUrd. The testicles were removed 1 h after injection, fixed in Bouin's fluid and embedded in paraffin. BrdUrd-labelled cells were detected by immunohistochemical staining using a monoclonal anti-BrdUrd antibody. The number of BrdUrd-labelled tubules per total number of tubules (percent L.T.), the number of BrdUrd-labelled cells per total number of tubules (tubular ratio) and the number of BrdUrd-labelled cells per number of Sertoli cells (Sertoli cell ratio in BrdUrd-labelled cells) were calculated as indices of spermatogenic DNA synthesis during each stage of the seminiferous epithelial wave. BrdUrd labelling was found exclusively in the nuclei of spermatogonia and in preleptotene spermatocytes in the seminiferous epithelium. The percent L.T. was generally greater than 50%, except in stages VI, VII and XIV, and the tubular as well as Sertoli cell ratios in BrdUrd-labelled cells was greater than 2.0 and 0.15, respectively, in stages I, II-III, V, VIII, X, and XII. The tubular ratio and Sertoli cell ratio in BrdUrd-labelled cells along the seminiferous epithelial wave had two distinct peaks. The distribution of the tubular ratio using the BrdUrd-labelling technique correlated well with the distribution previously established by measuring tritiated thymidine uptake per tubule. Thus, the BrdUrd labelling technique, which is more efficient than the tritiated thymidine labelling technique, can be used to quantitatively evaluate spermatogenic DNA synthesis. 相似文献
86.
Takahito Adachi Makoto Takeuchi Satomi Uno Motohisa Kato Kiichi Miya Shigetoyo Saji 《Surgery today》1997,27(12):1144-1149
Although tumor cryosurgery would be expected to produce beneficial immunological effects from the enhancement of anti-tumor
activity, under certain conditions the tumor may become enlarged and metastases promoted due to increased immunosuppressive
activity and a high zone tolerance. In the present study, we examined whether hepatocyteproliferating factors were produced
by the inoculation of freezing-thawing hepatic tissue (FTHT). Serum obtained from rats inoculated with FTHT increased DNA
synthesis, according to measurement by [3H]thymidine incorporation in primary cultured rat hepatocytes. This increase was dependent on the serum concentration, with
serum obtained on day 14 after the inoculation being the most potent for hepatocyte proliferation. The sensitized serum promoted
DNA synthesis nearly as much as serum obtained from a 70% hepatectomized rat, but slightly less than 10ng/ml hepatocyte growth
factor. The sensitized serum also protected hepatocytes from carbon tetrachloride (CCI4)-induced hepatotoxicity. Optical density measured by the 3-(4,5-dimethyl-thiazole-2-yl)-2,5-diphenyl tetrozolium bromide
(MTT) cytotoxicity assay was increased, and the release of aspartate aminotransferase, alanine aminotransferase, and lactate
dehydrogenase in medium was decreased by treating hepatocytes damaged by CCI4 with the sensitized serum. These results suggest that certain hepatocyte-proliferating and protective factors are induced
in serum by the inoculation of freezing-thawing hepatic tissue, and that the sensitized serum may be useful in the treatment
of liver failure. 相似文献
87.
Kalpana Agarwal Anita Mukherjee Archana Sharma Ramesh Sharma Kuldip Raj Bhardwaj Soumitra Sen 《Environmental and molecular mutagenesis》1992,19(4):323-326
Fenfluramine, an amphetamine derivative used in the treatment of obesity, has been evaluated in vivo in the bone marrow cells of Swiss albino mice using two cytogenetic endpoints for assessing its genotoxic and clastogenic potentials. Concentrations of 0.75, 1.5, 3.0, and 5.0 mg/kg b.w. were administered orally for the study of sister chromatid exchange frequencies and chromosome aberrations (CA). SCE frequencies showed a positive dose response; 1.5 mg/kg being the minimum effective concentration. Fen caused a prolongation of cell cycle at all concentrations. Except for the minimum therapeutic dose (0.75 mg), all other doses (1.5, 3.0, and 5.0 mg) showed a significant increase in the percentage of damaged cells over that of the vehicle control. The degree of clastogenicity was directly proportional to the dosage used and inversely related with the duration of treatment. A gradual reduction of the clastogenic potential was observed after 12 and 24 hr of exposure, indicating that the maximum effect occurs at the middle or late synthetic phase of the cell cycle. This study, probably the first detailed screening of the drug for its genotoxicity, shows that Fen is moderately clastogenic and a DNA damaging agent in vivo. 相似文献
88.
89.
目的:寻找适合于临床PCR检测结核杆菌DNA简单、快速、有效、经济的细菌裂解方法。方法:采用11种细菌裂解剂对相同数量的结核分枝杆菌进行裂解,裂解上清液直接用于PCR扩增,结果:1%TritonX-100,1%NP40,1%Teween20、和1%OP四种裂解剂的裂解液可直接扩增出结核分枝杆菌DNA;SDS,NaOH,十二烷基肌酸钠等裂解剂的裂解液直接用于PCR扩增均为阴性。结论:1%的Tritonx-100,NP40、Teween20和乳化剂OP裂解细菌效果好,又不抑制PCR反应,适合于作为临床PCR检测结核杆菌的裂解剂。 相似文献
90.
目的:建立测定生长激素(GH)在体生物活性的方法.方法:以去垂体大鼠体重增长(BWG)和胫骨骺软骨板宽度(TEW)为指标,观察动物性别、给药途径、次数和周期不同对效应的影响;同时进行4dBWG,6dBWG和6dTEW法,测定GH的效价(平行线3×3设计).结果:♀和♂sc和im给药以及每日给药1次和2次的BWG和TEW差异无显著意义.给药6d比给药4d引起较大的BWG和TEW(P<005).4dBWG法和6dBWG法在0020-0500IU·d-1有较好的λ值(00660和01747)和r值(09000和09237);4dBWG,6dBWG和6dTEW法测得rhGH的效价为46132,39829和48023IU/amp.6dBWG法有较小的λ值和较低的ARFL值.结论:可在同一组去垂体大鼠体内同时用4dBWG,6dBWG和6dTEW法测GH活性,以6dBWG法较好. 相似文献