全文获取类型
收费全文 | 7614篇 |
免费 | 466篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 84篇 |
儿科学 | 231篇 |
妇产科学 | 240篇 |
基础医学 | 1250篇 |
口腔科学 | 230篇 |
临床医学 | 752篇 |
内科学 | 1659篇 |
皮肤病学 | 185篇 |
神经病学 | 688篇 |
特种医学 | 150篇 |
外科学 | 669篇 |
综合类 | 49篇 |
一般理论 | 5篇 |
预防医学 | 694篇 |
眼科学 | 104篇 |
药学 | 503篇 |
中国医学 | 13篇 |
肿瘤学 | 601篇 |
出版年
2024年 | 7篇 |
2023年 | 64篇 |
2022年 | 158篇 |
2021年 | 295篇 |
2020年 | 167篇 |
2019年 | 234篇 |
2018年 | 249篇 |
2017年 | 210篇 |
2016年 | 231篇 |
2015年 | 247篇 |
2014年 | 276篇 |
2013年 | 405篇 |
2012年 | 650篇 |
2011年 | 604篇 |
2010年 | 346篇 |
2009年 | 294篇 |
2008年 | 532篇 |
2007年 | 542篇 |
2006年 | 484篇 |
2005年 | 519篇 |
2004年 | 398篇 |
2003年 | 374篇 |
2002年 | 324篇 |
2001年 | 36篇 |
2000年 | 30篇 |
1999年 | 46篇 |
1998年 | 49篇 |
1997年 | 43篇 |
1996年 | 43篇 |
1995年 | 40篇 |
1994年 | 30篇 |
1993年 | 33篇 |
1992年 | 20篇 |
1991年 | 19篇 |
1990年 | 12篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 10篇 |
1978年 | 3篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1947年 | 2篇 |
排序方式: 共有8107条查询结果,搜索用时 15 毫秒
21.
22.
In 50 partially edentulous patients, 133 (48 maxillary; 85 mandibular) Astra Tech dental implants of 2 different surface textures (machined; TiO‐blasted) were alternately installed, supporting 52 fixed partial dentures (FPDs). Before abutment connection 2 machined implants (1 mandibular; 1 maxillary) were found to be non-osseointegrated and were replaced. Another implant could not be restored due to a technical complication. Two FPDs were remade because of technical complications, both because of abutment fractures. Thus, after 2 years in function, the cumulative survival rates were 97.7% and 95.7% for implants and prostheses, respectively. There was no statistically significant difference in survival rate between the 2 types of implants, 100%(TiO‐blasted) vs 95.3%(machined), P =0.24. After 2 years in function, when both jaw and type of implants were combined, the mean (SD) marginal bone loss was 0.24 (0.69) mm. No statistically significant difference in bone loss was found between the 2 tvues of implant after 2 years of loading, 0.04 (0.82) mm, P >0.30. 相似文献
23.
Overexpression of connexin43 alters the mutant phenotype of midgestational wnt-1 null mice resulting in recovery of the midbrain and cerebellum 总被引:1,自引:0,他引:1
Melloy PG Kusnierczyk MK Meyer RA Lo CW Desmond ME 《The anatomical record. Part A, Discoveries in molecular, cellular, and evolutionary biology》2005,283(1):224-238
The midbrain-hindbrain (MHB) junction plays a key role in the patterning of the embryonic neural tube and the formation of brain structures such as the cerebellum. The mitogen wnt-1 is critical for cerebellar development, as evidenced by the lack of MHB region and cerebellar formation in the wnt-1 null embryo. We have generated wnt-1 null embryos overexpressing the gap junction gene connexin43 by crossing wnt-1 null heterozygotes into the CMV43 mouse line. We have confirmed that these mice show an increase in gap junctional communication by dye coupling analysis. Two-thirds of wnt-1 null CMV43(+) mouse embryos at E18.5 have a cerebellum. In addition, changes in the wnt-1 null phenotype in mouse embryos overexpressing connexin43 are observed as early as E9.5. At this stage, one-quarter of wnt-1 null CMV43(+) embryos display extra or expanded tissue present at the MHB boundary (a wnt-1 null enlarged phenotype). In situ hybridization studies conducted on these embryos have indicated no changes in the expression of embryonic brain positional markers in this region. We conclude from these studies that overexpression of the connexin43 gap junction restores cerebellar formation by compensating for the loss of wnt-1. 相似文献
24.
Effect of stimulation and hyperpolarization on non-electrolyte and sodium permeability in perfused axons of squid 总被引:1,自引:0,他引:1
1. The permeability for micro-injected [(3)H]ethylene glycol was measured in resting state and during stimulation at 100/sec in squid giant axons. No detectable changes during electrical activity were observed.2. The influxes of urethane, tritiated water, ethylene glycol, urea and sodium were measured in internally perfused squid axons. Ethylene glycol and urea influxes were determined simultaneously with sodium influxes. The electrical stimulation of the fibre produced an increase in the influx of sodium but did not alter the influxes of the non-electrolytes listed above.3. Experiments were done with the combined voltage clamp-perfusion technique. The influxes of ethylene glycol and sodium were simultaneously measured in resting state and during maximum sodium current under stimulation at 10/sec. The influx of sodium increased in these conditions but the influx of ethylene glycol remained constant. In some experiments, the fibre was hyperpolarized to 10 or 20 mV, above the resting potential and the influxes of ethylene glycol and sodium were measured. The sodium influx decreased to 60% at 20 mV above the resting potential whereas the influx of ethylene glycol remained constant.4. These results indicate that in the giant axons of the squid Dosidicus gigas, sodium and non-electrolytes fluxes are not coupled. 相似文献
25.
Alberto Utrero-Rico Javier Ruiz-Hornillos Cecilia González-Cuadrado Claudia Geraldine Rita Berta Almoguera Pablo Minguez Antonio Herrero-González Mario Fernández-Ruiz Octavio Carretero Juan Carlos Taracido-Fernández Rosario López-Rodriguez Marta Corton José María Aguado Luisa María Villar Carmen Ayuso-García Estela Paz-Artal Rocio Laguna-Goya 《The Journal of allergy and clinical immunology》2021,147(5):1652-1661.e1
26.
Josep Sul-Suso Flavio Arienti Cecilia Melani Mario Paolo Colombo Giorgio Parmiani 《European journal of immunology》1995,25(10):2737-2742
B7 co-stimulation is necessary to activate resting T cells upon antigen recognition by the T cell receptor. To see whether expression of B7 may render human melanoma cells able to stimulate T cells, a cloned melanoma line (Me1B6), which did not express B7-1, was transfected with the human B7-1 gene. In proliferation assays, B7-1 transfected cells (Me1B6/B7) showed greater stimulatory activity of allogeneic and autologous peripheral blood lymphocytes (PBL) compared to parental, non-transfected tumor cells. This effect was also seen when allogeneic CD8+ and CD4+ subpopulations were used as effectors. In these studies, activation of lymphocytes was B7-1-dependent and HLA classes I and II mediated. The higher proliferation correlated with an increased lytic activity by PBL stimulated with B7-1+ tumor cells against the untransfected Me1B6. Furthermore, PBL from a metastatic melanoma patient stimulated by Me1B6/B7 developed an higher lytic activity not only against Me1B6 but also against their autologous, B7-1? tumor. Finally, after Me1B6/B7 stimulation, PBL released interleukin (IL)-2 and interferon-γ, but not IL-4, suggesting a Th1-mediated response. These data support the use of B7-1 transfected melanoma cells in the therapeutic vaccination of melanoma patients. 相似文献
27.
28.
First report of capsule replacement among electrophoretic type 37 Neisseria meningitidis strains in Italy
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Stefanelli P Fazio C Neri A Sofia T Mastrantonio P 《Journal of clinical microbiology》2003,41(12):5783-5786
This report describes the C-to-B capsular switching in four Neisseria meningitidis strains belonging to the electrophoretic type 37 (ET-37) complex. In particular, one strain belonged to the new sequence type 1860, which was first detected in the year 2000 in Italy and is now frequently isolated. The presence of switched serogroup B strains deserves special attention if they prove as able to spread as their serogroup C progenitors belonging to the hypervirulent ET-37 complex. 相似文献
29.
Storlazzi CT Anelli L Surace C Lonoce A Zagaria A Nanni M Curzi P Rocchi M 《Cancer Genetics and Cytogenetics》2002,136(2):141-145
The "golden path", produced by the Human Genome Project effort, is composed of a collection of overlapping and fully sequenced BAC/PAC clones covering almost completely the human genome. These clones can be advantageously exploited as fluorescence in situ hybridization (FISH) probes for the characterization of rearrangements frequently found in tumors. Breakpoint characterization can be further refined by generating additional smaller FISH probes through LONG-PCR amplification of specific DNA segments, 5-10 kb in size, using appropriate BAC/PAC probes as template. We report here an example of this approach that has been used to characterize a complex Ph-negative chronic myeloid leukemia (CML Ph-) case in which the BCR/ABL fusion gene was found located on chromosome 9. 相似文献
30.
Fine-needle aspiration cytology remains a useful tool for preoperative diagnosis of breast lesions. We describe a case of adenoid cystic carcinoma (ACC) of the breast detected by ultrasound-guided fine-needle aspiration (FNA). Subsequent histopathology corroborated the diagnosis. ACC is a rare but distinctive neoplasm of the breast that can be accurately diagnosed by FNA. Its infrequent presentation, favorable prognosis, and relatively conservative management in the breast prompt us to reinforce its features. 相似文献