全文获取类型
收费全文 | 9925篇 |
免费 | 764篇 |
国内免费 | 204篇 |
专业分类
耳鼻咽喉 | 94篇 |
儿科学 | 374篇 |
妇产科学 | 325篇 |
基础医学 | 1322篇 |
口腔科学 | 96篇 |
临床医学 | 960篇 |
内科学 | 2525篇 |
皮肤病学 | 92篇 |
神经病学 | 477篇 |
特种医学 | 308篇 |
外科学 | 1633篇 |
综合类 | 297篇 |
一般理论 | 2篇 |
预防医学 | 649篇 |
眼科学 | 123篇 |
药学 | 788篇 |
中国医学 | 92篇 |
肿瘤学 | 736篇 |
出版年
2023年 | 63篇 |
2022年 | 75篇 |
2021年 | 203篇 |
2020年 | 137篇 |
2019年 | 199篇 |
2018年 | 262篇 |
2017年 | 184篇 |
2016年 | 197篇 |
2015年 | 249篇 |
2014年 | 318篇 |
2013年 | 391篇 |
2012年 | 560篇 |
2011年 | 605篇 |
2010年 | 356篇 |
2009年 | 346篇 |
2008年 | 478篇 |
2007年 | 625篇 |
2006年 | 535篇 |
2005年 | 515篇 |
2004年 | 482篇 |
2003年 | 396篇 |
2002年 | 373篇 |
2001年 | 378篇 |
2000年 | 338篇 |
1999年 | 310篇 |
1998年 | 139篇 |
1997年 | 170篇 |
1996年 | 137篇 |
1995年 | 110篇 |
1994年 | 99篇 |
1993年 | 55篇 |
1992年 | 174篇 |
1991年 | 151篇 |
1990年 | 144篇 |
1989年 | 129篇 |
1988年 | 134篇 |
1987年 | 116篇 |
1986年 | 93篇 |
1985年 | 67篇 |
1984年 | 51篇 |
1983年 | 61篇 |
1982年 | 38篇 |
1981年 | 29篇 |
1980年 | 26篇 |
1979年 | 65篇 |
1978年 | 32篇 |
1977年 | 33篇 |
1976年 | 32篇 |
1974年 | 27篇 |
1973年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
We report a case of an 83-year-old man with a high-grade carcinoma of the urinary bladder who underwent cystoprostatectomy. The invasive carcinoma showed mixed, morphologically distinct patterns consisting of conventional high-grade urothelial carcinoma, glandular differentiation resembling enteric type adenocarcinoma, and acinar/tubular type differentiation, morphologically similar to Gleason grade 3 prostatic adenocarcinoma. Immunohistochemical studies revealed the acinar/tubular component of the tumor to be negative for prostate-specific antigen and prostatic acid phosphatase, but positive for cytokeratin 7, cytokeratin 20, high molecular weight cytokeratin (34 beta E12), and thrombomodulin, consistent with origin from the bladder rather than the prostate. Although bladder carcinomas composed of mixed morphologic patterns are not uncommon, to our knowledge, the presence of acinar/tubular type features simulating prostatic adenocarcinoma in such tumors has not been described elsewhere. 相似文献
62.
Comparison of three different sensitive assays for hepatitis B virus DNA in monitoring of responses to antiviral therapy 总被引:7,自引:0,他引:7 下载免费PDF全文
The aim of our study was to compare the performances of two new hepatitis B virus (HBV) DNA assays, a cross-linking assay (NAXCOR) and a hybrid-capture amplification assay (Digene), versus the widely used branched-DNA (bDNA) assay (Chiron) in the monitoring of HBV DNA levels during antiviral treatment. Serial serum samples from 12 chronically HBV infected patients undergoing a phase II trial of an antiviral drug, 2',3'-dideoxy-5-fluoro-3'-thiacytidine (FTC), were studied. A total of 96 serum samples were tested for HBV DNA using the cross-linking, hybrid-capture amplification, and bDNA assays. In the comparison of the cross-linking and bDNA assays, concordant results were found in 77 (80.3%) samples, no significant difference was found between the median log(10) HBV DNA levels (6.66 versus 7. 17 meq/ml), and the results of the two assays were closely correlated (r = 0.95). In the comparison of the hybrid-capture amplification and bDNA assays, concordant results were found in 79 (82.3%) samples, no significant difference was found between the median log(10) HBV DNA levels (6.98 versus 6.99 meq/ml), and the results of the two assays were closely correlated (r = 0.99). Six (6. 3%) samples by the cross-linking assay and 10 (10.4%) samples by the bDNA assay required retesting because of unacceptably high within-run coefficients of variance. No sample required retesting in the hybrid-capture amplification assay according to the internal validation. In conclusion, the cross-linking and hybrid-capture amplification assays were as sensitive as the bDNA assay for HBV DNA detection and can be recommended for monitoring of HBV DNA levels during antiviral treatment. 相似文献
63.
P Y Liu Y J Lau B S Hu J M Shir M H Cheung Z Y Shi W S Tsai 《Journal of clinical microbiology》1994,32(8):1935-1938
A method to characterize strains of Serratia marcescens based on the PCR amplification of enterobacterial repetitive intergenic consensus sequences has been developed. The PCR fingerprints were generated from boiled supernatants prepared directly from bacterial colonies without the need for DNA extraction. The technique was applied to isolates obtained during an outbreak of pneumonia from seven mechanically ventilated patients, and its result indicated that the outbreak was due to the spread of two epidemic strains. This technique was validated by comparison with rRNA gene restriction analysis. There was complete concordance between these two techniques in discriminating the outbreak-related strains from epidemiologically unrelated isolates. Typing with both biochemical profile and antibiogram profile, though simple, was found to be less reliable than genotyping. The results show that this enterobacterial repetitive intergenic consensus PCR provides a rapid and simple means of typing S. marcescens isolates for epidemiologic studies. 相似文献
64.
Detection of highly pathogenic and low pathogenic avian influenza subtype H5 (Eurasian lineage) using NASBA 总被引:15,自引:0,他引:15
Nucleic acid sequence-based amplification (NASBA) is a technique that allows the rapid amplification of specific regions of nucleic acid obtained from a diverse range of sources. It is especially suitable for amplifying RNA sequences. A NASBA technique has been developed that allows the detection of avian influenza A subtype H5 from allantoic fluid harvested from inoculated chick embryos. The amplified viral RNA is detected by electrochemiluminescence. The NASBA technique described below is rapid and specific for the identification of influenza A subtype H5 viruses of the Eurasian lineage. More importantly, it can be used to distinguish highly pathogenic and low pathogenic strains of the H5 subtype. 相似文献
65.
Fugger EF; Black SH; Keyvanfar K; Schulman JD 《Human reproduction (Oxford, England)》1998,13(9):2367-2370
The world's first deliveries of normal babies after use of flow cytometric
separated human sperm cells (MicroSort) for preconception gender selection
are reported. Offspring were of the desired female gender in 92.9% of the
pregnancies. Most of these pregnancies and births were achieved after
simple intrauterine insemination.
相似文献
66.
M B Dahlke C Cooke M Cunnane J Chawla P Lau 《American journal of clinical pathology》1977,68(6):740-746
Of 500 patients seen because of rape, semen was identified in vaginal secretions by the identification of spermatozoa in 61%, by an acid phosphatase value of 50 units or more in 40%, and by the identification of a foreign blood group substance or a high titer of own blood group substance in 16%. The addition of the determination of the acid phosphatase to the search for spermatozoa identified semen in only 1.4% more patients, or a total of 62.4%. Identification and titers of blood group substance were confirmatory only, but further characterized the source of the semen in 25% of those patients with spermatozoa. Spermatozoa were identified for as long as 48 hours, and elevated acid phosphatase was not found after 18 hours. Acid phosphatase was elevated in only 62% of patients with spermatozoa. 相似文献
67.
J Y Lau H M Smith K Chaggar L J Hansen B C Portmann G J Alexander R Williams 《Journal of medical virology》1991,33(4):273-276
Intrahepatic hepatitis D virus (HDV) antigen (HDAg) and serum HDV RNA are excellent markers of active HDV replication but the relation of IgM anti-HDV to HDV replication and histological activity is less certain. To further elucidate the significance of serum IgM anti-HDV, 90 paired sera and liver biopsies from 64 patients seropositive for total antibody to HDV were analysed for IgM anti-HDV, intrahepatic HDAg expression, and histological inflammatory activity. IgM anti-HDV was strongly associated with intrahepatic HDAg expression with a sensitivity of 94.1% but the assay lacked specificity since 14 out of 22 cases negative for intrahepatic HDAg were also positive for IgM anti-HDV. In 20 patients in whom follow-up biopsies and paired sera were available, two patients lost intrahepatic HDAg but paired serum remained IgM anti-HDV positive. Although the presence of serum IgM anti-HDV correlated significantly with a higher histological inflammatory activity (P = 0.001), there was a considerable overlap with the group seronegative for IgM anti-HDV, again indicating a poor specificity. This lack of specificity of IgM anti-HDV for both HDV replication and histological activity indicates that this assay provides no additional information over and above assay for total antibody to HDV. 相似文献
68.
Mahadevaiah SK; Odorisio T; Elliott DJ; Rattigan A; Szot M; Laval SH; Washburn LL; McCarrey JR; Cattanach BM; Lovell-Badge R; Burgoyne PS 《Human molecular genetics》1998,7(4):715-727
An RNA-binding motif (RBM) gene family has been identified on the human Y
chromosome that maps to the same deletion interval as the 'azoospermia
factor' (AZF). We have identified the homologous gene family (Rbm) on the
mouse Y with a view to investigating the proposal that this gene family
plays a role in spermatogenesis. At least 25 and probably >50 copies of
Rbm are present on the mouse Y chromosome short arm located between Sry and
the centromere. As in the human, a role in spermatogenesis is indicated by
a germ cell-specific pattern of expression in the testis, but there are
distinct differences in the pattern of expression between the two species.
Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are
female due to a position effect resulting in non-expression of Sry ;
sex-reversing such mice with an Sry transgene produces males with a high
incidence of abnormal sperm, making this the third deletion interval on the
mouse Y that affects some aspect of spermatogenesis. Most of the copies of
Rbm map to this deletion interval, and the Yd1males have markedly reduced
Rbm expression, suggesting that RBM deficiency may be responsible for, or
contribute to, the abnormal sperm development. In man, deletion of the
functional copies of RBM is associated with meiotic arrest rather than
sperm anomalies; however, the different effects of deletion are consistent
with the differences in expression between the two species.
相似文献
69.
C Lau S Budz-Tymkewycz M Ramsden P Lee E C Keystone 《Clinical and experimental immunology》1985,61(3):489-495
Peripheral blood T cells from patients with rheumatoid arthritis (RA) and scleroderma (PSS) were assessed for their ability to release T-cell-specific suppressor activity (TRSA) upon incubation with a suppressor activating factor (SAF) derived from a human lymphoblastoid cell line (CEM). T cells from 11/20 (55%) RA patients exhibited impaired TRSA release in contrast to 1/12 (8%) of PSS patients. RA patients demonstrating impaired TRSA release exhibited more active arthritis than patients demonstrating normal TRSA release. 相似文献
70.