全文获取类型
收费全文 | 75836篇 |
免费 | 6070篇 |
国内免费 | 4197篇 |
专业分类
耳鼻咽喉 | 1061篇 |
儿科学 | 825篇 |
妇产科学 | 576篇 |
基础医学 | 8122篇 |
口腔科学 | 1146篇 |
临床医学 | 7672篇 |
内科学 | 10230篇 |
皮肤病学 | 1074篇 |
神经病学 | 3338篇 |
特种医学 | 3795篇 |
外国民族医学 | 8篇 |
外科学 | 9984篇 |
综合类 | 13686篇 |
现状与发展 | 14篇 |
一般理论 | 3篇 |
预防医学 | 5523篇 |
眼科学 | 1532篇 |
药学 | 7688篇 |
57篇 | |
中国医学 | 4256篇 |
肿瘤学 | 5513篇 |
出版年
2024年 | 164篇 |
2023年 | 717篇 |
2022年 | 1918篇 |
2021年 | 2750篇 |
2020年 | 2119篇 |
2019年 | 1886篇 |
2018年 | 2010篇 |
2017年 | 2045篇 |
2016年 | 2167篇 |
2015年 | 3338篇 |
2014年 | 4290篇 |
2013年 | 4703篇 |
2012年 | 6861篇 |
2011年 | 6995篇 |
2010年 | 5469篇 |
2009年 | 4676篇 |
2008年 | 5280篇 |
2007年 | 5048篇 |
2006年 | 4683篇 |
2005年 | 3987篇 |
2004年 | 3129篇 |
2003年 | 3036篇 |
2002年 | 2688篇 |
2001年 | 1771篇 |
2000年 | 1154篇 |
1999年 | 723篇 |
1998年 | 438篇 |
1997年 | 433篇 |
1996年 | 306篇 |
1995年 | 236篇 |
1994年 | 192篇 |
1993年 | 124篇 |
1992年 | 105篇 |
1991年 | 118篇 |
1990年 | 73篇 |
1989年 | 67篇 |
1988年 | 59篇 |
1987年 | 53篇 |
1986年 | 41篇 |
1985年 | 47篇 |
1984年 | 20篇 |
1983年 | 22篇 |
1982年 | 23篇 |
1981年 | 14篇 |
1980年 | 14篇 |
1979年 | 17篇 |
1978年 | 12篇 |
1977年 | 10篇 |
1973年 | 9篇 |
1971年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
患者女,76岁.因发现左腹股沟肿物2个月,于2007年9月来本院就诊.门诊B超检查:左腹股沟多个肿大淋巴结,不融合,考虑为淋巴瘤.门诊手术取左腹股沟淋巴结1枚. 相似文献
52.
Fertility clinics worldwide routinely produce a large volume of 'waste' follicular aspirate, which is potentially an abundant source of immature ovarian follicles. Current attempts to cultivate these further in vitro to yield viable mature oocytes for fertility treatment have not yet achieved much success. Instead, recent lines of evidence have emerged that are suggestive of a potential stem cell niche within such immature ovarian follicles. The recent discovery of follicular renewal and putative germ-line stem cells within the postnatal mammalian ovary shook the foundations of reproductive biology by challenging the established dogma that mammalian females lose the capacity for germ cell renewal during fetal life, such that a fixed reserve of germ cells (oocytes) enclosed within follicles is endowed at birth. More intriguingly, another recent study in the Drosophila model provided compelling evidence that somatic progenies (nurse cells) of germ-line stem cells had the ability to revert back to the stem-cell-like state. This introduces the exciting possibility that within the mammalian ovarian follicle, similar somatic progenies of germ-line stem cells may also possess a greater intrinsic ability to revert back into functional stem cells. If this is the case, then a favored candidate would be the cumulus/granulosa of immature ovarian follicles, since such cells are true homologues of nurse cells found within the Drosophila ovary. The successful elucidation of a human germ-line stem cell niche within immature ovarian follicles is likely to have huge ramifications in stem cell biology and regenerative medicine. 相似文献
53.
54.
55.
Yong D Lim JG Choi JR Park Q Yang CH Choi SH Jeong HJ Song KS 《Yonsei medical journal》2000,41(1):136-139
Klinefelter syndrome (KS) is often associated with various neoplasms, especially germ cell tumors. Mediastinum is the most favored site of extragonadal germ cell tumors with KS, which is somewhat different from those without KS. The retroperitoneal germ cell tumor in KS is very rare. A five-month-old boy with an abdominal mass was found to have a retroperitoneal tumor. After surgical removal, he was diagnosed to have mature cystic teratoma. Cytogenetic study of his peripheral lymphocytes revealed that his karyotype was consistent with KS. This case suggests that patients with KS might be at risk of having germ cell tumors in sites other than mediastinum. It also suggests that all cases with these tumors should be screened for the presence of karyotypic abnormalities, and it might help to assess the exact correlation between germ cell tumors and KS, and to treat them accordingly. 相似文献
56.
Multispacer typing of Rickettsia prowazekii enabling epidemiological studies of epidemic typhus 下载免费PDF全文
Currently, there is no tool for typing Rickettsia prowazekii, the causative agent of epidemic typhus, currently considered a potential bioterrorism agent, at the strain level. To test if the multispacer typing (MST) method could differentiate strains of R. prowazekii, we amplified and sequenced the 25 most variable intergenic spacers between the R. prowazekii and R. conorii genomes in five strains and 10 body louse amplicons of R. prowazekii from various geographic origins. Two intergenic spacers, i.e., rpmE/tRNA(fMet) and serS/virB4, were variable among tested R. prowazekii isolates and allowed identification of three and two genotypes, respectively. When the genotypes obtained from the two spacers were combined, we identified four different genotypes. MST demonstrated that several R. prowazekii strains circulated in human body lice during an outbreak of epidemic typhus in Burundi. This may help to discriminate between natural and intentional outbreaks. Our study supports the usefulness of MST as a versatile method for rickettsial strain genotyping. 相似文献
57.
目的:探讨钠氢交换体Ⅰ型(NHE-1)特异性抑制剂cariporide对快速起搏所致兔心房电重构的影响。 方法: 30只兔随机等分为3组:对照组、起搏组和cariporide组。起搏组和cariporide组给予6 h 600 beats/min的快速心房起搏。测定各组不同时点的心房有效不应期(AERP200,AERP150,AERP130),连续刺激6 h后取左右心耳组织,用Western blotting测定NHE-1的含量。 结果: 在快速起搏后1 h后,起搏组的AERP200较起搏前明显缩短,2 h时达高峰,相对缩短量为(15.63±9.04)ms,而对照组和cariporide组AERP未发生明显变化,起搏2h时相对缩短量为(1.43±2.44)ms和(1.43±6.90)ms(P<0.05,与起搏组相比),这些变化一直保持至快速起搏后6 h;起搏组的AERP频率适应性下降, 起搏前AERP130较AERP200缩短(11.88±15.57)ms,起搏后6 h只缩短(4.38±5.63)ms。而cariporide组的AERP频率适应性则未发生显著变化。起搏组右心耳组织的NHE-1含量显著少于对照组(P<0.05),cariporide组的右心耳组织NHE-1含量与对照组差异不显著。 结论: Cariporide可有效阻止快速心房起搏引起的AERP缩短,但不影响起搏引起的NHE-1含量的下降。 相似文献
58.
目的:探讨HIE患者血中6-keto-PGF1α、NSE水平变化及临床意义.方法:用RIA检测89例HIE患者和32例正常新生儿血中6-keto-PGF1α、NSE水平变化.结果:HIE轻、中、重度组6-keto-PGF1α水平与正常对照组比较,均存在显著性差异(p<0.01),HIE患者轻度组NSE水平与对照组比较无显著性差异(p>0.05),中、重度组NSE水平与对照组比较存在显著性差异(p<0.01),6-keto-PGF1α、NSE二组血中浓度上升与HIE程度呈正相关.结论:HIE患者中6-keto-PGF1α、NSE水平检测,对判断HIE的脑损伤程度、治疗、预后观察,具有重要临床意义和应用价值. 相似文献
59.
Incidence and outcome of adenovirus disease in transplant recipients after reduced-intensity conditioning with alemtuzumab. 总被引:4,自引:0,他引:4
Irit Avivi Suparno Chakrabarti Donald W Milligan H Waldmann Geoff Hale Husam Osman Katherine N Ward Christopher D Fegan Kwee Yong Anthony H Goldstone David C Linch Stephen Mackinnon 《Biology of blood and marrow transplantation》2004,10(3):186-194
Adenoviruses are emerging as a major cause of infectious complications after allogeneic transplantation. We evaluated the incidence and outcome of symptomatic adenovirus infection or adenovirus disease after alemtuzumab-based reduced-intensity conditioning in 86 consecutive patients. The overall probability of adenovirus disease was 18.4% (11/86 patients). Five patients died of progressive adenovirus disease, and this was the most important infectious cause of mortality in this cohort. The probability of nonrelapse mortality was 49% in patients with adenovirus disease compared with 25.5% in those without (P=.007). The severity of lymphocytopenia and continuation of immunosuppressive therapy were the most important risk factors for progressive adenovirus disease and death. In contrast, patients who were not receiving immunosuppressive therapy or had had it reduced or withdrawn cleared the virus. We also detected a correlation between the lack of preemptive anti-cytomegalovirus (CMV) therapy for CMV reactivation and the risk of progressive adenovirus disease (P=.05). Our findings highlight the emergence of adenovirus as an important posttransplantation pathogen even after reduced-intensity conditioning and demonstrate the effect of the severity of lymphocytopenia, anti-CMV prophylaxis, and immunosuppressive therapy on the outcome of adenovirus disease. 相似文献
60.
Reconstitution of T-cell repertoire after autologous stem cell transplantation: influence of CD34 selection and cytomegalovirus infection. 总被引:6,自引:0,他引:6
Karl S Peggs Stephanie Verfuerth Arnold Pizzey Naeem Khan Paul Moss Anthony H Goldstone Kwee Yong Stephen Mackinnon 《Biology of blood and marrow transplantation》2003,9(3):198-205
The period of immunodeficiency following autologous hematopoietic stem cell transplantation is characterized by transient expansions of CD8+CD45RO+CD57+ T lymphocytes, displaying markers of an activated phenotype. Most evidence suggests that this early reconstitution results from proliferation of mature T cells that have survived conditioning or were transferred with the graft. Although homeostatic mechanisms are thought to act in maintaining total T-cell numbers, the degree to which antigen-driven expansions contribute and the nature of the stimulating antigens remain unclear. CD34 selection of stem cell grafts reduces the available T-cell pool, potentially delaying immune reconstitution and resulting in increased infective complications. In the allogeneic transplantation setting, lymphopenia has been associated with cytomegalovirus (CMV) infection risk and, if persistent, with adverse outcome. We prospectively studied patients undergoing CD34-selected (n = 13) or unselected (n = 13) autologous hematopoeitic stem cell transplantation for immune reconstitution and CMV infection. No significant differences were demonstrated between graft types with respect to lymphocyte subset recovery, T-cell receptor beta-chain variable region spectratype diversity, or CMV DNA detection rates (45% versus 40%). CMV infection was associated with a trend toward higher rather than lower CD8+ counts at 6 weeks posttransplantation (P =.08) that became significant by 3 months (P=.007), and that was associated with decreased T-cell receptor beta-chain variable region spectratype diversity (P =.01). CMV-specific HLA-tetramer analysis demonstrated transient expansions with CDR3 lengths corresponding to those of some of the major posttransplantation T-cell expansions demonstrated by spectratype analysis suggesting that CMV-specific T cells contribute to the pattern of immune reconstitution. 相似文献