全文获取类型
收费全文 | 7164篇 |
免费 | 707篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 57篇 |
儿科学 | 299篇 |
妇产科学 | 231篇 |
基础医学 | 902篇 |
口腔科学 | 166篇 |
临床医学 | 797篇 |
内科学 | 1435篇 |
皮肤病学 | 113篇 |
神经病学 | 648篇 |
特种医学 | 218篇 |
外科学 | 836篇 |
综合类 | 241篇 |
一般理论 | 8篇 |
预防医学 | 941篇 |
眼科学 | 83篇 |
药学 | 436篇 |
中国医学 | 1篇 |
肿瘤学 | 481篇 |
出版年
2023年 | 107篇 |
2022年 | 139篇 |
2021年 | 322篇 |
2020年 | 184篇 |
2019年 | 281篇 |
2018年 | 318篇 |
2017年 | 196篇 |
2016年 | 177篇 |
2015年 | 209篇 |
2014年 | 332篇 |
2013年 | 401篇 |
2012年 | 579篇 |
2011年 | 570篇 |
2010年 | 308篇 |
2009年 | 247篇 |
2008年 | 406篇 |
2007年 | 419篇 |
2006年 | 379篇 |
2005年 | 346篇 |
2004年 | 288篇 |
2003年 | 246篇 |
2002年 | 264篇 |
2001年 | 104篇 |
2000年 | 91篇 |
1999年 | 62篇 |
1998年 | 34篇 |
1997年 | 25篇 |
1996年 | 39篇 |
1995年 | 39篇 |
1994年 | 21篇 |
1993年 | 35篇 |
1992年 | 40篇 |
1991年 | 39篇 |
1990年 | 57篇 |
1989年 | 40篇 |
1988年 | 21篇 |
1987年 | 37篇 |
1986年 | 23篇 |
1985年 | 22篇 |
1984年 | 31篇 |
1983年 | 30篇 |
1980年 | 19篇 |
1979年 | 23篇 |
1978年 | 21篇 |
1975年 | 21篇 |
1973年 | 27篇 |
1972年 | 19篇 |
1970年 | 24篇 |
1969年 | 20篇 |
1967年 | 18篇 |
排序方式: 共有7893条查询结果,搜索用时 343 毫秒
51.
The use of ion exchange chromatography, gel filtration, and paper electrophoresis for the separation of the peptides obtained by tryptic digestion of the cowpea strain of tobacco mosaic virus protein is described. The amino acid compositions of the 13 tryptic peptides obtained were determined and accounted for 159 residues compared with the 158 found for type tobacco mosaic virus protein. The only tryptic peptide that cowpea tobacco mosaic virus protein and type tobacco mosaic virus protein have in common is asparaginyl-arginine despite the fact that the former is very similar to type tobacco mosaic virus protein in a number of its properties. The amino terminal sequence was found to be acetyl alanyl-tyrosine and the carboxyl terminal sequence was confirmed as alanine preceded by threonine. 相似文献
52.
We report a case of mantle cell lymphoma histologically indistinguishable from marginal zone lymphoma. An 83-year-old man presented with a 9.0-cm, slowly enlarging axillary mass. Microscopically, the neoplastic process was largely interfollicular, surrounding residual follicular centers, some of which had discernible small lymphocyte mantles. Overall, the morphologic pattern was highly suggestive of marginal zone lymphoma. However, flow cytometric and immunohistochemical results, including cyclin D1 positivity, revealed an immunophenotype that fit with mantle cell lymphoma. The differential diagnosis of mantle cell lymphoma is broad, and it is well known that mantle cell lymphoma can assume a number of histologic appearances, including, infrequently, that of more indolent B-cell non-Hodgkin lymphomas. Although not pathognomonic, cyclin D1 positivity is highly specific for mantle cell lymphoma and is key in distinguishing these clinically dissimilar malignant lymphomas. In recent years, detection of cyclin D1 has expanded the recognizable histologic spectrum of mantle cell lymphoma. 相似文献
53.
Hernandez Natalie D. Francis Sherilyn Allen Morgan Bellamy Erica Sims Omar T Oh Hyejung Guillaume Dominique Parker Andrea Chandler Rasheeta 《Maternal and child health journal》2022,26(4):770-777
Maternal and Child Health Journal - Data are scarce regarding the prevalence and predictors of perinatal mood and anxiety disorders (PMADs) among Black women. The purpose of this study was to... 相似文献
54.
BackgroundIndividuals’ perceptions of their fecundity, or biological ability to bear children, have important implications for health behaviors, including infertility help-seeking and contraceptive use. Little research has examined these perceptions among U.S. women.MethodsThis cross-sectional study examines perceptions of one's own fecundity among U.S. women aged 24 to 32 who participated in the 2009–2011 rounds of the National Longitudinal Survey of Youth (1997) cohort. Analyses were limited to 3,088 women who indicated that they or their partners never received a doctor's diagnosis regarding fertility difficulties.ResultsOf the women in the sample, 67% perceived their hypothetical chances of becoming pregnant as very likely; the remainder perceived their chances as somewhat likely (13%), not as likely (15%), or provided a “don't know” response (6%). Twenty-six percent of Black women and 19% of Latina women perceived themselves as not very likely to become pregnant, compared with only 12% among non-Black/non-Latina women (p < .001). Only 6% of women with a college degree perceived their chances of becoming pregnant as not very likely, compared with 36% among women without a high school degree (p < .001). Racial/ethnic and educational differences persisted in fully adjusted models. Other factors associated with fecundity self-perceptions include partnership status, parity, fertility expectations, sexual activity, prolonged exposure to unprotected intercourse for at least 6 and/or 12 months without becoming pregnant, and self-rated health.ConclusionsFindings indicate that self-perceived fecundity differs systematically by demographic and other characteristics. This phenomenon should be investigated further to understand how it may influence disparities in health behaviors and outcomes. 相似文献
55.
56.
Liese C.C. Pruitt Zachary J. Kastenberg Stephen J. Fenton Scott S. Short 《Journal of pediatric surgery》2021,56(3):629-631
PurposeExperience with autologous blood patch (ABP) pleurodesis for persistent air leak in the pediatric population is limited. The purpose of this series was to describe the experience with ABP at a single tertiary children's hospital.MethodsA retrospective study was performed of all thoracic procedures done by the pediatric surgery service over three years.ResultsTen patients underwent a total of 17 ABPs. The median age of patients was 12 years (IQR 6–16). The most common underlying reasons for a thoracic procedure included: blebectomy for spontaneous pneumothorax (2), need for lung biopsy (2), resection of known malignant tumor (2), and empyema (2). The median number of days of persistent air leak before first ABP was 7.5 days (IQR 7–10). A second ABP was performed in 6 cases with a third procedure performed in one case. None of the patients developed respiratory compromise during ABP and no infectious complications were identified following ABP.ConclusionsOur cohort demonstrates that ABP for persistent air leak following thoracic surgery is effective with minimal morbidity in children. We believe ABP can be used early and in patients with a broad range of underlying lung pathology. 相似文献
57.
58.
Isabel Beshar Jodi So Meena Chelvakumar Erica P. Cahill Kate A. Shaw Jonathan G. Shaw 《Contraception》2021,103(4):246-254
59.
Immunogenicity of fowlpox virus expressing the avian influenza virus H5 gene (TROVAC AIV-H5) in cats 总被引:4,自引:0,他引:4
Karaca K Swayne DE Grosenbaugh D Bublot M Robles A Spackman E Nordgren R 《Clinical and diagnostic laboratory immunology》2005,12(11):1340-1342
Vaccination of cats with fowlpox virus expressing the avian influenza (AI) virus H5 hemagglutinin gene (TROVAC AI) resulted in detectable hemagglutination inhibition (HI) antibody responses to the homologous A/Turkey/Ireland/1378/83 (H5N8) (A/tky/Ire/83) AI virus antigen. The HI antibody responses to heterologous A/Chicken/Indonesia/7/03 (H5N1) (A/ck/Indonesia/03) AI virus antigen were also detected in all vaccinated cats, but only after booster vaccinations. The vaccine described in this study and other poxvirus-vectored vaccines may be of value for the prophylaxis of AI virus-associated morbidity and mortality in mammals. 相似文献
60.
Gene delivery to glioma cells in rat brain by grafting of a retrovirus packaging cell line 总被引:9,自引:0,他引:9
M P Short B C Choi J K Lee A Malick X O Breakefield R L Martuza 《Journal of neuroscience research》1990,27(3):427-439
Retrovirus vectors only integrate into the genome of dividing cells and can thus be used to selectively infect tumor cells in the adult rat brain. Gene delivery was assessed by using the retrovirus BAG vector, which bears the Escherichia coli lacZ gene under the MoMLV LTR promoter-enhancer element, and by histochemical staining for bacterial beta-galactosidase activity. Direct injection of this vector (90-900 cfu) into the adult rat brain, with or without prior inoculation of C6 glioma cells (2 x 10(5) cells) resulted in labeling of only a few cells as assessed 1 week later. When the psi 2-BAG packaging line was grafted into the brain, labeled psi 2-BAG cells could be found after 1 day, but not after 5 days, following grafting, suggesting that the grafted cells had been rejected and that no endogenous cells had integrated released vector, or that expression of lacZ had been turned off. In contrast, when the psi 2-BAG packaging line was grafted into a brain region, which had been inoculated previously with rat C6 glioma cells (2 x 10(5) cells), beta-galactosidase labeling of these tumor cells, identified by immunocytochemistry for glial fibrillary acidic protein and S100, could be demonstrated 10 days later. Thus, grafting of retrovirus packaging lines into adult brain provides a mean to infect tumor cells in situ. The grafted packaging cells may continue to release retrovirus particles for an extended period, thus infecting more cells at the stage of division appropriate for viral integration, as compared to inoculation of the virus alone. Grafting of retrovirus packaging cell lines could be used to selectively deliver "killer" or "suppressor" genes to tumor cells in the brain to curtail their growth. 相似文献