全文获取类型
收费全文 | 113004篇 |
免费 | 7162篇 |
国内免费 | 854篇 |
专业分类
耳鼻咽喉 | 1249篇 |
儿科学 | 3362篇 |
妇产科学 | 2639篇 |
基础医学 | 15061篇 |
口腔科学 | 2841篇 |
临床医学 | 9190篇 |
内科学 | 25418篇 |
皮肤病学 | 2388篇 |
神经病学 | 10252篇 |
特种医学 | 4274篇 |
外国民族医学 | 24篇 |
外科学 | 16392篇 |
综合类 | 1704篇 |
一般理论 | 53篇 |
预防医学 | 6552篇 |
眼科学 | 1675篇 |
药学 | 8674篇 |
3篇 | |
中国医学 | 551篇 |
肿瘤学 | 8718篇 |
出版年
2023年 | 516篇 |
2022年 | 1013篇 |
2021年 | 2278篇 |
2020年 | 1428篇 |
2019年 | 2060篇 |
2018年 | 2578篇 |
2017年 | 1908篇 |
2016年 | 2013篇 |
2015年 | 2342篇 |
2014年 | 3107篇 |
2013年 | 4430篇 |
2012年 | 6000篇 |
2011年 | 6360篇 |
2010年 | 4012篇 |
2009年 | 3580篇 |
2008年 | 5579篇 |
2007年 | 5807篇 |
2006年 | 5536篇 |
2005年 | 5393篇 |
2004年 | 5625篇 |
2003年 | 5332篇 |
2002年 | 5346篇 |
2001年 | 4041篇 |
2000年 | 3957篇 |
1999年 | 3216篇 |
1998年 | 1305篇 |
1997年 | 1026篇 |
1996年 | 952篇 |
1995年 | 921篇 |
1994年 | 804篇 |
1993年 | 784篇 |
1992年 | 1928篇 |
1991年 | 1897篇 |
1990年 | 1622篇 |
1989年 | 1549篇 |
1988年 | 1428篇 |
1987年 | 1288篇 |
1986年 | 1276篇 |
1985年 | 1146篇 |
1984年 | 851篇 |
1983年 | 758篇 |
1982年 | 509篇 |
1981年 | 424篇 |
1979年 | 620篇 |
1978年 | 455篇 |
1975年 | 471篇 |
1974年 | 506篇 |
1973年 | 494篇 |
1972年 | 440篇 |
1971年 | 414篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Phase 1 trial of the topical microbicide BufferGel: safety results from four international sites 总被引:2,自引:0,他引:2
van De Wijgert J Fullem A Kelly C Mehendale S Rugpao S Kumwenda N Chirenje Z Joshi S Taha T Padian N Bollinger R Nelson K 《Journal of acquired immune deficiency syndromes (1999)》2001,26(1):21-27
AIM: To evaluate the safety of BufferGel (ReProtect LLC, Baltimore, MD), a spermicidal microbicide that acidifies semen and maintains the protective acidity of the vagina, in a high-dose tolerance trial. METHODS: HIV/STD negative, sexually abstinent, and sexually active women in India, Thailand, Malawi, and Zimbabwe were asked to insert one applicator ( approximately 5 ml) of BufferGel vaginally twice per day for 14 days. Sexually active women agreed to have sex (while using BufferGel and nonlubricated condoms) at least twice per week. RESULTS: In total, 98 women (30 sexually abstinent and 68 sexually active) were enrolled. Overall compliance with product use was 93%. Epithelial abnormalities detected by pelvic examination or colposcopy were uncommon (8 cases in 271 examinations). Irritation was reported by approximately one quarter of the women (0.58 events per woman-week) but was generally mild and of short duration. The prevalence of bacterial vaginosis (BV) fell significantly, from 30% at enrollment to 6% at one week, and 7% at two weeks of BufferGel use. Thirty-two women acquired microscopically detectable yeast during BufferGel exposure, but only 3 developed symptomatic vaginitis. CONCLUSION: BufferGel appears to be safe and well tolerated by the cervicovaginal epithelium. Its effect on BV and yeasts merits further study. 相似文献
992.
993.
Antonella Gambale Roberta Russo Immacolata Andolfo Lucia Quaglietta Gianluca De Rosa Valentina Contestabile Lucia De Martino Rita Genesio Piero Pignataro Sabrina Giglio Mario Capasso Rosanna Parasole Barbara Pasini Achille Iolascon 《Clinical genetics》2019,96(4):359-365
Cancer predisposition syndromes (CPS) result from germline pathogenic variants, and they are increasingly recognized in the etiology of many pediatric cancers. Herein, we report the genetic/genomic analysis of 40 pediatric patients enrolled from 2016 to 2018. Our diagnostic workflow was successful in 50% of screened cases. Overall, the proportion of CPS in our case series is 10.9% (20/184) of enrolled patients. Interestingly, 12.5% of patients achieved a conclusive diagnosis through the analysis of chromosomal imbalance. Indeed, we observed germline microdeletions/duplications of regions encompassing cancer-related genes in 50% of patients undergoing array-CGH: EIF3H duplication in a patient with infantile desmoplastic astrocytoma and low-grade Glioma; SLFN11 deletion, SOX4 duplication, and PARK2 partial deletion in three neuroblastoma patients; a PTPRD partial deletion in a child diagnosed with glioblastoma multiforme. Finally, we identified two cases due to DICER1 germline mutations. 相似文献
994.
A case of primary low grade B cell lymphoma of the salivary gland associated with a low grade B cell lymphoma of the thymus and involvement of the skin is reported. The lesions in the salivary gland and in the thymus showed the typical features of a lymphoma arising from the mucosa associated lymphoid tissue (MALT) and comprised lymphatic follicles, centrocyte-like (CCL) cells and lymphoepithelial lesions. Immunohistochemistry and Southern blot analysis supported the hypothesis that these lesions can originate from the same cellular clone. These findings confirm the occurrence of low grade B cell MALT lymphoma in the thymus and the possibility of spread of MALT lymphoma to other mucosal sites. 相似文献
995.
G. Martinelli P. Farabegoli M. Buzzi G. Panzica A. Zaccaria G. Bandini E. Calori N. Testoni G. Rosti R. Conte C. Remiddi M. Salvucci A. De Vivo S. Tura 《International journal of immunogenetics》1996,23(1):55-65
The degree of matching of HLA genes between the selected donor and recipient is an important aspect of the selection of unrelated donors for allogeneic bone marrow transplantation (UBMT). The most sensitive methods currently used are serological typing of HLA class I genes, mixed lymphocyte culture (MLC), IEF and molecular genotyping of HLA class II genes by direct sequencing of PCR products. Serological typing of class I antigenes (A, B and C) fails to detect minor differences demonstrated by direct sequencing of DNA polymorphic regions. Molecular genotyping of HLA class I genes by DNA analysis is costly and work-intensive. To improve compatibility between donor and recipient, we have set up a new rapid and non-radioisotopic application of the ‘fingerprinting PCR’ technique for the analysis of the polymorphic second exon of the HLA class I A, B and C genes. This technique is based on the formation of specific patterns (PCR fingerprints) of homoduplexes and heterodu-plexes between heterologous amplified DNA sequences. After an electrophoretic run on non-denaturing polyacrylamide gel, different HLA class I types give allele-specific banding patterns. HLA class I matching is performed, after the gel has been soaked in ethidium bromide or silver-stained, by visual comparison of patients’ fingerprints with those of donors. Identity can be confirmed by mixing donor and recipient DNAs in an amplification cross-match. To assess the technique, 10 normal samples, 22 related allogeneic bone marrow transplanted pairs and 10 unrelated HLA-A and HLA-B serologically matched patient-donor pairs were analysed for HLA class I polymorphic regions. In all the related pairs and in 1/10 unrelated pairs, matched donor-recipient patterns were identified. This new application of PCR fingerprinting may confirm the HLA class I serological selection of unrelated marrow donors. 相似文献
996.
J. Gutierrez M. C. Maroto A. De la Higuera M. Guerrero E. Padilla G. Piédrola 《European journal of clinical microbiology & infectious diseases》1995,14(6):542-546
The prevalence of anti-Borrelia burgdorferi antibodies was studied in Granada, Spain, between January 1991 and November 1993 in 354 patients with suspected Lyme disease (group 1); in 50 patients either with syphilis (n=32) or without syphilis but with a positive Rapid Plasma Reagin test (n=18) (group 2); and in 150 healthy subjects (group 3). In addition, intrathecal antibody production was evaluated by EIA in CSF samples obtained from 117 patients in group 1. Anti-Borrelia burgdorferi antibodies were detected by EIA in 58 patients (16.4 %) in group 1, 29 (8.2 %) of whom were positive by Western blot. Intrathecal antibody production was detected in one patient. In group 2, 8 (16 %) patients had a positive EIA result, but none of these was confirmed by Western blot. Western blot was negative for all subjects in group 3. The results of this study indicate that anti-Borrelia burgdorferi antibodies are not uncommon in our area, although Lyme disease is rare. 相似文献
997.
Muriel Moser Thibaut De Smedt Thierry Sornasse Franoise Tielemans Aziz Alami Chentoufi Eric Muraille Marcelle Van Mechelen Jacques Urbain Oberdan Leo 《European journal of immunology》1995,25(10):2818-2824
Exogenous glucocorticoid hormones are widely used as therapeutical agents, whereas endogenous glucocorticoids may act as physiological immunosuppressants involved in the control of immune and inflammatory responses. The optimal activation of T lymphocytes requires two distinct signals: the major histocompatibility complex-restricted presentation of the antigen and an additional co-stimulatory signal provided by the antigen-presenting cells. There is ample evidence that, among the cells able to present the antigen, the dendritic cells (DC) have the unique property to activate antigen-specific, naive T cells in vitro and in vivo, and are therefore required for the induction of primary immune responses. In this work, we tested whether glucocorticoids affected the capacity of DC to sensitize naive T cells. Our data show that, in vitro, the steroid hormone analog dexamethasone (Dex) affects the viability of DC, selectively downregulates the expression of co-stimulatory molecules on viable DC, and strongly reduces their immunostimulatory properties. In vivo, a single injection of Dex results in impaired antigen presenting function, a finding which correlates with reduced numbers of splenic DC. These results show that glucocorticoids regulate DC maturation and immune function in vitro and in vivo and suggest that this mechanism may play a role in preventing overstimulation of the immune system. 相似文献
998.
Sylvie De Kossodo Brigitte Critico Georges E. Grau 《European journal of immunology》1994,24(3):769-772
We investigated the effects of a single bacterial lipopolysaccharide (LPS) injection in vivo on the gene expression of tumor necrosis factor-α (TNF) and its receptors: TNF receptor type I (TNF-R 55 kDa or TNF-R1) and TNF receptor type II (TNF-R 75 kDa or TNF-R2) in various tissues and white blood cells. While TNF mRNA rapidly accumulated in most tissues, TNF-R1 and TNF-R2 mRNA levels were found to be differentially regulated in lung, spleen, lymph nodes and white blood cells. In most cases, TNF-R mRNA levels did not parallel TNF mRNA levels. These observations indicate that TNF-R of both types are capable of modulating the host response to LPS, not only by shedding of their extracellular domains, but also by strict regulation of their gene expression. 相似文献
999.
Structure of critical point dried oncornaviruses 总被引:3,自引:0,他引:3
1000.
Adequate hemodialysis schedule 总被引:1,自引:0,他引:1
J R De Palma C F Bolton M A Baltzan R B Baltzan 《The New England journal of medicine》1971,285(6):353-354