全文获取类型
收费全文 | 11364篇 |
免费 | 2614篇 |
国内免费 | 136篇 |
专业分类
耳鼻咽喉 | 375篇 |
儿科学 | 325篇 |
妇产科学 | 286篇 |
基础医学 | 492篇 |
口腔科学 | 177篇 |
临床医学 | 3063篇 |
内科学 | 2127篇 |
皮肤病学 | 343篇 |
神经病学 | 969篇 |
特种医学 | 510篇 |
外科学 | 1561篇 |
综合类 | 384篇 |
现状与发展 | 2篇 |
预防医学 | 1874篇 |
眼科学 | 203篇 |
药学 | 319篇 |
1篇 | |
中国医学 | 100篇 |
肿瘤学 | 1003篇 |
出版年
2024年 | 81篇 |
2023年 | 415篇 |
2022年 | 125篇 |
2021年 | 279篇 |
2020年 | 502篇 |
2019年 | 206篇 |
2018年 | 589篇 |
2017年 | 621篇 |
2016年 | 649篇 |
2015年 | 738篇 |
2014年 | 758篇 |
2013年 | 1106篇 |
2012年 | 476篇 |
2011年 | 425篇 |
2010年 | 579篇 |
2009年 | 678篇 |
2008年 | 400篇 |
2007年 | 326篇 |
2006年 | 378篇 |
2005年 | 288篇 |
2004年 | 243篇 |
2003年 | 186篇 |
2002年 | 184篇 |
2001年 | 254篇 |
2000年 | 207篇 |
1999年 | 221篇 |
1998年 | 311篇 |
1997年 | 317篇 |
1996年 | 329篇 |
1995年 | 261篇 |
1994年 | 192篇 |
1993年 | 141篇 |
1992年 | 139篇 |
1991年 | 137篇 |
1990年 | 130篇 |
1989年 | 157篇 |
1988年 | 120篇 |
1987年 | 90篇 |
1986年 | 94篇 |
1985年 | 92篇 |
1984年 | 81篇 |
1983年 | 69篇 |
1982年 | 47篇 |
1981年 | 64篇 |
1980年 | 38篇 |
1979年 | 32篇 |
1978年 | 29篇 |
1977年 | 33篇 |
1976年 | 28篇 |
1975年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Distress and DNA repair in human lymphocytes 总被引:3,自引:0,他引:3
Janice K. Kiecolt-Glaser Ralph E. Stephens Philip D. Lipetz Carl E. Speicher Ronald Glaser 《Journal of behavioral medicine》1985,8(4):311-320
This research assessed differences in DNA repair in lymphocytes from high-and low-distressed individuals. A median split on Minnesota Multiphasic Personality Inventory (MMPI) Scale 2 divided 28 newly admitted nonpsychotic psychiatric inpatients into high- and low-distress subgroups. The high-distress subgroup had significantly poorer DNA repair in lymphocytes exposed to X-irradiation than low-distress subjects. We also found that lymphocytes obtained from this psychiatric sample had significantly poorer DNA repair than lymphocytes from nonpsychiatric control subjects when compared 5 hr after X-irradiation. A high level of distress therefore appears to be associated with significant dysfunctional differences at the molecular level which may have important implications for health. These data provide evidence for a direct pathway through which distress could influence the incidence of cancer.This research was funded in part by General Molecular Applications, Inc., the Bremer Foundation, the Samuel J. Roessler Fund, and Comprehensive Cancer Center Core Grant CA-16068-09. 相似文献
102.
Linkage exclusion and mutational analysis of the noggin gene in patients with fibrodysplasia ossificans progressiva (FOP) 总被引:1,自引:0,他引:1
Xu MQ Feldman G Le Merrer M Shugart YY Glaser DL Urtizberea JA Fardeau M Connor JM Triffitt J Smith R Shore EM Kaplan FS 《Clinical genetics》2000,58(4):291-298
Fibrodysplasia ossificans progressiva (FOP) is an extremely rare and disabling genetic disorder characterized by congenital malformation of the great toes and by progressive heterotopic endochondral ossification in predictable anatomical patterns. Although elevated levels of bone morphogenetic protein 4 (BMP4) occur in lymphoblastoid cells and in lesional cells of patients with FOP, mutations have not been identified in the BMP4 gene, suggesting that the mutation in FOP may reside in a BMP4-interacting factor or in another component of the BMP4 pathway. A powerful antagonist of BMP4 is the secreted polypeptide noggin. A recent case report described a heterozygous 42-bp deletion in the protein-coding region of the noggin gene in a patient with FOP. In order to determine if noggin mutations are a widespread finding in FOP, we examined 31 families with 1 or more FOP patients. Linkage analysis with an array of highly polymorphic microsatellite markers closely linked to the noggin gene was performed in four classically-affected multigenerational FOP families and excluded linkage of the noggin locus to FOP (the multipoint lod score was -2 or less throughout the entire range of markers). We sequenced the noggin gene in affected members of all four families, as well as in 18 patients with sporadic FOP, and failed to detect any mutations. Single-strand conformation polymorphism (SSCP) analysis of 4 of these patients plus an additional 9 patients also failed to reveal any mutations. Among the samples analyzed by SSCP and DNA sequencing was an independently obtained DNA sample from the identical FOP patient previously described with the 42-bp noggin deletion; no mutation was detected. Examination of the DNA sequences of 20 cloned noggin PCR products, undertaken to evaluate the possibility of a somatic mutation in the noggin gene which could be carried by a small subset of white blood cells, also failed to detect the presence of the reported 42-bp deletion. We conclude that mutations in the coding region of noggin are not associated with FOP. 相似文献
103.
To determine whether biological and/or biochemical variants exist between strains of Epstein-Barr virus (EBV), we superinfected Raji cells with the nontransforming lytic strain of EBV (HR-1), and two isolates that both transform B-lymphocytes and superinfect Raji cells, B95–8, and NPC-EBV. The superinfected cells were assayed for EBV specific DNase. A new electrophoretic form of DNase was observed in cells superinfected with B95-8 EBV as compared to the enzymes induced by the HR-1 and NPC-EBV isolates. There were antigenic differences in the DNase induced by the EBV strains. Since antibody to EBV DNase is a marker for nasopharyngeal carcinoma (NPC), these data may have implications for EBV-associated disease. 相似文献
104.
105.
Sequence comparison of human and yeast telomeres identifies structurally distinct subtelomeric domains 总被引:6,自引:2,他引:6
Flint J; Bates GP; Clark K; Dorman A; Willingham D; Roe BA; Micklem G; Higgs DR; Louis EJ 《Human molecular genetics》1997,6(8):1305-1313
We have sequenced and compared DNA from the ends of three human
chromosomes: 4p, 16p and 22q. In all cases the pro-terminal regions are
subdivided by degenerate (TTAGGG)n repeats into distal and proximal sub-
domains with entirely different patterns of homology to other chromosome
ends. The distal regions contain numerous, short (<2 kb) segments of
interrupted homology to many other human telomeric regions. The proximal
regions show much longer (approximately 10-40 kb) uninterrupted homology to
a few chromosome ends. A comparison of all yeast subtelomeric regions
indicates that they too are subdivided by degenerate TTAGGG repeats into
distal and proximal sub-domains with similarly different patterns of
identity to other non-homologous chromosome ends. Sequence comparisons
indicate that the distal and proximal sub-domains do not interact with each
other and that they interact quite differently with the corresponding
regions on other, non- homologous, chromosomes. These findings suggest that
the degenerate TTAGGG repeats identify a previously unrecognized,
evolutionarily conserved boundary between remarkably different subtelomeric
domains.
相似文献
106.
Horne G; Jamaludin A; Critchlow JD; Falconer DA; Newman MC; Oghoetuoma J; Pease EH; Lieberman BA 《Human reproduction (Oxford, England)》1998,13(11):3045-3048
Insemination with donor spermatozoa is an integral part of infertility
treatment. For the last 3 years in our unit, intrauterine insemination with
donor spermatozoa (IUID) has been used in preference to vaginal
insemination. In this retrospective study, patients were offered an initial
course of five single intrauterine inseminations with cryopreserved donor
spermatozoa and treatment was then reviewed. A total of 389 patients
received 1465 inseminations. In all, 1119 cycles were monitored using
luteinizing hormone serum analyses and 346 cycles using the urine home test
kits. The clinical pregnancy rate per insemination for the cycles monitored
by the serum assay was 18.0% (202/1119) compared with the urine cycles
(13.7%, 46/346) (P <05). The pregnancy loss rate was not significantly
different (14.4%, 29/202 and 21.7%, 10/46) (serum and urine cycles
respectively). The viable clinical pregnancy rate was significantly higher
(P <03) for the serum cycles than for the cycles using the urinary
monitoring (15.5%, 173/1119 and 10.4%, 36/346 respectively). The cycles
monitored by serum assay had a significantly higher cumulative viable
clinical pregnancy rate (P <0001) of 70.2% after nine inseminations
compared with the urine monitored cycles of 54.8%. The majority of patients
opted for the serum cycles, with a minority self-selecting the urine cycles
mainly for travelling convenience. The explanation for the significant
differences between the viable clinical pregnancy rates per insemination
and the cumulative viable clinical pregnancy rates may be due to the
sensitivity of the urine home test kit or the patients' interpretation of
the result.
相似文献
107.
Cindy Johnston Stephan Eliez Jennifer Dyer‐Friedman David Hessl Bronwyn Glaser Christine Blasey Annette Taylor Allan Reiss 《American journal of medical genetics. Part A》2001,103(4):314-319
There have been contradictory findings in the fragile X (fraX) literature about possible neurocognitive and psychological symptoms due to the fraX premutation (pM). The purpose of the present study was to investigate the relationship between CGG repeat length and neurobehavioral functioning in carriers of the fraX pM. Eighty‐five female carriers of the pM with allele sizes ranging from 59–166 were administered a comprehensive IQ test (WAIS‐III) and completed a questionnaire designed to measure psychopathology (Symptom Checklist (SCL)‐90‐R). No relationship between allele size and cognition was identified. A significant negative relationship between allele size and age was found, as well as a positive relationship between allele size and depression. Follow‐up analyses separating small and large allele sizes (below and above 100 CGG repeats) indicated that individuals with larger allele sizes scored significantly higher on the Interpersonal Sensitivity and Depression subscales of the SCL‐90‐R. Despite the limitation of few individuals with high CGG repeat lengths, our findings suggest that females with larger premutated alleles (≥ 100 repeats) display some clinical manifestations of fraX syndrome. © 2001 Wiley‐Liss, Inc. 相似文献
108.
Methodological aspects of DNA image cytometry in formalin-fixed paraffin-embedded material from pancreatic adenocarcinoma 总被引:1,自引:0,他引:1
A R Weger G Mikuz U Askensten G U Auer G Schwab K S Glaser 《Pathology, research and practice》1989,185(5):752-754
Deparaffinized and disintegrated material from conventionally formalin-fixed and paraffin-embedded surgical specimens of 100 cases of ductal adenocarcinoma of the pancreas was Feulgen-stained, and the cytochemical DNA distribution patterns of at least 100 single tumour cells and 50 "control" cells (fibrocytes) were assessed by means of image cytometry (ICM). In 77 cases a sufficient number of neoplastic cells could be obtained for these DNA assessments. The fairly high number (23) of cases that had to be excluded due to too small amounts of disintegrated cells or cell nuclei may be explained by the high content of connective tissue stroma in these pancreatic adenocarcinomas. The tumour cell nuclei in 76 of these 77 cases showed cytochemically a clear-cut "non-diploid" DNA distribution pattern. This observation reflects the well-known highly malignant growth potential of this carcinoma. Despite the fact that about 1/4 of the tumours had to be excluded, the main result of our methodological study is, after all that conventionally formalin-fixed paraffin-embedded specimens of most pancreatic adenocarcinomas can be successfully used for the deparaffinization-disintegration procedure preceding the nuclear DNA assessments by means of ICM. Additional studies are, however, required to obtain the diagnostic and prognostic impact of the results of such cytochemical analyses of the DNA distribution pattern in adenocarcinomas of the pancreas. 相似文献
109.