全文获取类型
收费全文 | 17845篇 |
免费 | 1111篇 |
国内免费 | 138篇 |
专业分类
耳鼻咽喉 | 112篇 |
儿科学 | 494篇 |
妇产科学 | 370篇 |
基础医学 | 2879篇 |
口腔科学 | 347篇 |
临床医学 | 1481篇 |
内科学 | 4520篇 |
皮肤病学 | 301篇 |
神经病学 | 1819篇 |
特种医学 | 450篇 |
外科学 | 1332篇 |
综合类 | 48篇 |
一般理论 | 5篇 |
预防医学 | 1395篇 |
眼科学 | 208篇 |
药学 | 1330篇 |
1篇 | |
中国医学 | 61篇 |
肿瘤学 | 1941篇 |
出版年
2024年 | 76篇 |
2023年 | 208篇 |
2022年 | 392篇 |
2021年 | 677篇 |
2020年 | 409篇 |
2019年 | 541篇 |
2018年 | 583篇 |
2017年 | 484篇 |
2016年 | 547篇 |
2015年 | 596篇 |
2014年 | 752篇 |
2013年 | 1000篇 |
2012年 | 1621篇 |
2011年 | 1619篇 |
2010年 | 891篇 |
2009年 | 799篇 |
2008年 | 1307篇 |
2007年 | 1205篇 |
2006年 | 1153篇 |
2005年 | 996篇 |
2004年 | 907篇 |
2003年 | 758篇 |
2002年 | 652篇 |
2001年 | 84篇 |
2000年 | 47篇 |
1999年 | 94篇 |
1998年 | 122篇 |
1997年 | 99篇 |
1996年 | 93篇 |
1995年 | 50篇 |
1994年 | 44篇 |
1993年 | 49篇 |
1992年 | 28篇 |
1991年 | 25篇 |
1990年 | 23篇 |
1989年 | 9篇 |
1988年 | 12篇 |
1987年 | 17篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 17篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1975年 | 5篇 |
1973年 | 10篇 |
1971年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
The risk of needing help with household tasks or of requiring care in old age increases. Using semi-structured, qualitative interviews, beliefs about the usefulness versus uselessness of planning ahead for future care needs (FCN) were investigated in 23 East German, 10 U.S., and 10 Canadian elderly-community dwelling women ( S 65 years). Primary reasons in favor of planning for FCN were: gaining a feeling of security regarding the future, avoiding being a burden to potential helpers, and coping with one's present health conditions. Factors that prevent planning for FCN were: the difficulty foreseeing FCN, the lack of resources to plan, and low levels of perceived vulnerability. The women dealt with the contradictions between these factors that promote and prevent preparation by making general plans which could be adapted in the case of needing help by developing alternative plans or by avoidance of thinking about possible future health crises. 相似文献
83.
84.
85.
86.
This study examined factors affecting young adults' attitudes about nonfatal suicidal behavior. It evaluated how respondent sex, respondent gender identity, the precipitant of the suicidal act (i.e., a relationship loss, an achievement failure, or a physical illness), and gender of the suicidal person influence reactions to a suicidal decision. In this study of nonfatal suicidal behavior, like in studies of suicide, attitudes were least negative when the suicidal act was in response to a physical illness. Men were more likely to agree with and accept the suicidal decision than women. Androgynous persons, on the other hand, tended to view the decision to kill oneself as foolish, independent of precipitant. They also reported less agreement, acceptance, and sympathy for such decision. The implications of these findings for the prevention of suicidal behaviors are considered. Because gender seems to play a role in the acceptability of suicidal behavior, prevention programs ought to explicitly examine gender issues in attitudes toward suicidal behavior. 相似文献
87.
88.
Induction of neural-like differentiation in human mesenchymal stem cells derived from bone marrow, fat, spleen and thymus 总被引:5,自引:0,他引:5
Krampera M Marconi S Pasini A Galiè M Rigotti G Mosna F Tinelli M Lovato L Anghileri E Andreini A Pizzolo G Sbarbati A Bonetti B 《BONE》2007,40(2):382-390
Mesenchymal stem cells (MSCs) from bone marrow (BM) and sub-cutaneous fat are known to differentiate into neural cells under appropriate stimuli. We describe here the neural-like differentiation of human MSCs obtained from spleen and thymus, induced either with chemical factors or with co-culture with human Schwann cells (Sc). Under the effect of neural differentiation medium, most MSCs from BM, fat, spleen and thymus acquired morphological changes suggestive of cells of astrocytic/neuronal and oligodendroglial lineages with general up-regulation of neural molecules not correlated with morphological changes. The process was transient and reversible, as MSCs recovered basal morphology and phenotype, as well as their multilineage differentiation potential. Thus, we hypothesized that chemical factors may prime MSCs for neural differentiation, by inducing initial and poorly specific changes. By contrast, co-cultures of MSCs of different origin with Sc induced long-lasting and Sc differentiation, i.e., the expression of Sc myelin proteins for up to 12 days. Our results show that a MSC reservoir is present in tissues other than BM and fat, and that MSCs of different origin have similar neural differentiation potential. This evidence provides new insights into BM-like tissue plasticity and may have important implications for future therapeutic interventions in chronic neuropathies. 相似文献
89.
Garcez AS Ribeiro MS Tegos GP Núñez SC Jorge AO Hamblin MR 《Lasers in surgery and medicine》2007,39(1):59-66
BACKGROUND AND OBJECTIVE: To compare the effectiveness of antimicrobial photodynamic therapy (PDT), standard endodontic treatment and the combined treatment to eliminate bacterial biofilms present in infected root canals. STUDY DESIGN/MATERIALS AND METHODS: Ten single-rooted freshly extracted human teeth were inoculated with stable bioluminescent Gram-negative bacteria, Proteus mirabilis and Pseudomonas aeruginosa to form 3-day biofilms in prepared root canals. Bioluminescence imaging was used to serially quantify bacterial burdens. PDT employed a conjugate between polyethylenimine and chlorin(e6) as the photosensitizer (PS) and 660-nm diode laser light delivered into the root canal via a 200-micro fiber, and this was compared and combined with standard endodontic treatment using mechanical debridement and antiseptic irrigation. RESULTS: Endodontic therapy alone reduced bacterial bioluminescence by 90% while PDT alone reduced bioluminescence by 95%. The combination reduced bioluminescence by >98%, and importantly the bacterial regrowth observed 24 hours after treatment was much less for the combination (P<0.0005) than for either single treatment. CONCLUSIONS: Bioluminescence imaging is an efficient way to monitor endodontic therapy. Antimicrobial PDT may have a role to play in optimized endodontic therapy. 相似文献
90.
Godfrey C Escolar D Brockington M Clement EM Mein R Jimenez-Mallebrera C Torelli S Feng L Brown SC Sewry CA Rutherford M Shapira Y Abbs S Muntoni F 《Annals of neurology》2006,60(5):603-610
OBJECTIVE: Defects in glycosylation of alpha-dystroglycan are associated with several forms of muscular dystrophy, often characterized by congenital onset and severe structural brain involvement, collectively known as dystroglycanopathies. Six causative genes have been identified in these disorders including fukutin. Mutations in fukutin cause Fukuyama congenital muscular dystrophy. This is the second most common form of muscular dystrophy in Japan and is invariably associated with mental retardation and structural brain defects. The aim of this study was to determine the genetic defect in two white families with a dystroglycanopathy. METHODS: The six genes responsible for dystroglycanopathies were studied in three children with a severe reduction of alpha-dystroglycan in skeletal muscle. RESULTS: We identified pathogenic fukutin mutations in these two families. Affected children had normal intelligence and brain structure and shared a limb girdle muscular dystrophy (LGMD) phenotype, had marked elevation of serum creatine kinase, and were all ambulant with remarkable steroid responsiveness. INTERPRETATION: Our data suggest that fukutin mutations occur outside Japan and can be associated with much milder phenotypes than Fukuyama congenital muscular dystrophy. These findings significantly expand the spectrum of phenotypes associated with fukutin mutations to include this novel form of limb girdle muscular dystrophy that we propose to name LGMD2L. 相似文献