全文获取类型
收费全文 | 191篇 |
免费 | 6篇 |
国内免费 | 4篇 |
专业分类
儿科学 | 6篇 |
妇产科学 | 7篇 |
基础医学 | 12篇 |
口腔科学 | 4篇 |
临床医学 | 19篇 |
内科学 | 74篇 |
皮肤病学 | 2篇 |
神经病学 | 2篇 |
特种医学 | 51篇 |
外科学 | 5篇 |
综合类 | 7篇 |
预防医学 | 4篇 |
眼科学 | 1篇 |
药学 | 3篇 |
肿瘤学 | 4篇 |
出版年
2023年 | 1篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2017年 | 1篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 1篇 |
2012年 | 4篇 |
2011年 | 3篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2008年 | 4篇 |
2007年 | 7篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2001年 | 1篇 |
1999年 | 3篇 |
1998年 | 7篇 |
1997年 | 13篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 21篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1967年 | 1篇 |
1959年 | 6篇 |
1958年 | 7篇 |
1957年 | 1篇 |
1956年 | 2篇 |
1955年 | 2篇 |
1949年 | 2篇 |
排序方式: 共有201条查询结果,搜索用时 31 毫秒
91.
92.
93.
The meiotic competence of in-vitro matured human oocytes is influenced by donor age: evidence that folliculogenesis is compromised in the reproductively aged ovary 总被引:11,自引:13,他引:11
Volarcik K; Sheean L; Goldfarb J; Woods L; Abdul-Karim FW; Hunt P 《Human reproduction (Oxford, England)》1998,13(1):154-160
The human oocyte appears to be particularly prone to meiotic errors, and
the incidence of these errors is strongly influenced by maternal age. We
have initiated studies of human oocytes from unstimulated ovaries and have
observed age-related effects on the meiotic process in oocytes from
unselected antral follicles. Specifically, in oocytes obtained from donors
over the age of 35 years, the majority of oocytes that extruded a first
polar body in culture and arrested at second meiotic metaphase had
aberrations in spindle formation and chromosome alignment. Similarly,
observations of a limited number of oocytes at first meiotic metaphase
suggest disturbances at this stage of meiosis as well. Finally, preliminary
results of non-disjunction studies suggest that the frequency of errors in
chromosome segregation at the first meiotic division is influenced by donor
age in in-vitro matured oocytes as it is in oocytes undergoing meiotic
maturation in vivo. These data provide direct evidence that the meiotic
competence of oocytes from unstimulated ovaries declines with donor age.
Similarly, studies of in-vitro fertilization (IVF) pregnancies in older
women indicate that the developmental competence of the human oocyte
declines with age. Since both meiotic and developmental competence are
acquired during the late stages of oocyte growth, we postulate that an age-
related decline in the process of folliculogenesis results in reduced
oocyte quality and that the well characterized age-related increase in
meiotic non-disjunction is one symptom of compromised oocyte growth.
相似文献
94.
Balancing immunosuppression to prevent rejection in solid organ transplant (SOT) recipients remains challenging. Torque teno virus (TTV), a commensal non-pathogenic virus, has been proposed as marker of functional immunity: higher loads correspond to over-immunosuppression, and lower loads to under-immunosuppression. This review offers an overview of the current evidence of the association between TTV-load and infection and rejection after SOT. A systematic literature search strategy, deposited in the PROSPERO registry, resulted in 548 records. After screening, 23 original and peer-reviewed articles were assessed investigating the association between TTV-load, infection and/or rejection in SOT. The Quality in Prognostic Studies (QUIPS)-tool was used to assess the risk of bias. Meta-analysis with random-effects was performed on results with similar outcomes and exposure measures. Most of the included studies involved retrospective cohorts in which the TTV-load was measured longitudinally, within the first 2 years post-transplantation. Infection outcomes differed between studies and included viral, bacterial, parasitic and fungal infections. Rejection was defined by biopsy confirmation or initiation of rejection treatment. Twelve out of 16 studies reported an association between high TTV-load and infections, whereas 13 out of 15 reported an association between low TTV-load and rejection. Meta-analysis showed an increased risk of infection (OR: 1.16, 95% CI: 1.03–1.32; HR: 1.05, 95% CI: 0.97–1.14) and a decreased risk of rejection (OR: 0.90, 95% CI: 0.87–0.94; HR: 0.74, 95% CI: 0.71–0.76) per 1 log TTV-load increase. The qualitative assessment showed varying risks of bias in the included studies. This systematic review and meta-analysis indicates that blood TTV-load measured within the first 2 years after SOT is associated with the risk of infection or allograft rejection, although substantial risk of bias in the studies included warrant cautious interpretation. The results in this review provide a rationale for larger, prospective, studies into TTV as marker of infection and rejection after SOT. 相似文献
95.
Khan WN; Nilsson A; Mizoguchi E; Castigli E; Forsell J; Bhan AK; Geha R; Sideras P; Alt FW 《International immunology》1997,9(3):395-405
Mutations in Bruton's tyrosine kinase (Btk) gene, in mice, result in
reduced numbers and responses of peripheral B cells. Surface Ig- mediated
signaling is defective in Btk mutant B cells as they do not proliferate
upon slg cross-linking and lack thymus-independent (TI) type II responses.
Signals through sIg and CD40 play a critical role in B cell maturation. To
investigate the consequences of the lack of both Btk and CD40 on B cell
development and function, mice were generated that were homozygous for
targeted mutations in the Btk and the CD40 genes (BtkMCD40M). The CD40
mutation (CD40M) had a synergistic effect on the BtkM defects. In BtkMCD40M
mice the number of B cells was reduced 3- to 4-fold compared to BtkM mice
and mature B cells (IgMlow/IgDhigh) were virtually absent; serum levels of
all Ig isotypes were diminished; and antibody responses to TI-I TI-II and
thymus- dependent antigens were impaired. Furthermore, although wild-type
BtkM and CD40M mice produced germinal centers in response to TI-I antigen,
the BtkMCD40M mice did not. Maturational and functional B cell defects in
BtkMCD40M mice may result from a combination of intrinsic B cell defects,
lack of CD40L-dependent T cell help and microenvironmental defects. These
data suggest that signals through Btk and CD40 are necessary for the
production and maintenance of the mature B cell.
相似文献
96.
97.
98.
Vincent CC Cheng Josepha WM Tai WM Chan Eric HY Lau Jasper FW Chan Kelvin KW To Iris WS Li PL Ho KY Yuen 《BMC infectious diseases》2010,10(1):263
Background
After renovation of the adult intensive care unit (ICU) with installation of ten single rooms, an enhanced infection control program was conducted to control the spread of methicillin-resistant Staphylococcus aureus (MRSA) in our hospital. 相似文献99.
van de Pol AC Wolfs TF Jansen NJ van Loon AM Rossen JW 《Critical care (London, England)》2006,10(2):R61-7
Introduction
The aetiology of lower respiratory tract infections in young children admitted to the paediatric intensive care unit (PICU) is often difficult to establish. However, most infections are believed to be caused by respiratory viruses. A diagnostic study was performed to compare conventional viral tests with the recently developed real-time PCR technique. 相似文献100.
Summary. Inherited defects of platelet function are a heterogeneous group of disorders that can result in bleeding symptoms ranging from mild bruising to severe mucocutaneous haemorrhage. These defects may be classified according to their effect on the various steps of platelet microthrombi formation including initiation, extension and cohesion, or based on their particular structural or functional deficiency. Platelet membrane receptor deficiencies result in the rare, but well‐characterized syndromes of defective clot initiation, such as Bernard–Soulier Syndrome. Platelet storage pool defects are the most common disorders affecting the extension phase of clot formation. Glanzmann thrombasthenia, with absent or dysfunctional αIIbβ3 receptor is the prototypical defect of the cohesion/aggregation phase of microthrombi formation. Many of these disorders share common treatments although some therapies will have greater efficacy for one patient than another and should be individualized so as to provide optimal control of symptoms. Currently much effort is being put into methods to more rapidly and accurately diagnose patients with platelet disorders and to initiate appropriate therapy and prevent life threatening bleeding. 相似文献