全文获取类型
收费全文 | 1339篇 |
免费 | 76篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 75篇 |
妇产科学 | 45篇 |
基础医学 | 108篇 |
口腔科学 | 53篇 |
临床医学 | 180篇 |
内科学 | 322篇 |
皮肤病学 | 27篇 |
神经病学 | 49篇 |
特种医学 | 258篇 |
外科学 | 108篇 |
综合类 | 49篇 |
预防医学 | 62篇 |
眼科学 | 22篇 |
药学 | 60篇 |
中国医学 | 4篇 |
肿瘤学 | 49篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 23篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2017年 | 14篇 |
2016年 | 16篇 |
2015年 | 22篇 |
2014年 | 28篇 |
2013年 | 34篇 |
2012年 | 28篇 |
2011年 | 28篇 |
2010年 | 40篇 |
2009年 | 52篇 |
2008年 | 29篇 |
2007年 | 73篇 |
2006年 | 38篇 |
2005年 | 36篇 |
2004年 | 27篇 |
2003年 | 28篇 |
2002年 | 31篇 |
2001年 | 28篇 |
2000年 | 38篇 |
1999年 | 27篇 |
1998年 | 67篇 |
1997年 | 75篇 |
1996年 | 76篇 |
1995年 | 65篇 |
1994年 | 44篇 |
1993年 | 54篇 |
1992年 | 24篇 |
1991年 | 23篇 |
1990年 | 30篇 |
1989年 | 49篇 |
1988年 | 33篇 |
1987年 | 45篇 |
1986年 | 24篇 |
1985年 | 31篇 |
1984年 | 20篇 |
1983年 | 28篇 |
1982年 | 25篇 |
1981年 | 17篇 |
1980年 | 24篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1966年 | 2篇 |
排序方式: 共有1481条查询结果,搜索用时 15 毫秒
11.
12.
13.
Anti-angiogenic effects of Hypericin-photodynamic therapy in combination with Celebrex in the treatment of human nasopharyngeal carcinoma 总被引:4,自引:0,他引:4
Photodynamic therapy (PDT) is being investigated as an alternative treatment modality in cancer treatment. It has been shown to induce tumor hypoxia and upregulation of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF). The objective of this study was to improve in vivo tumor growth control of nasopharyngeal carcinoma (NPC), treated at a subcurative dosage by using a combination of Hypericin-PDT and COX-2 inhibitor, Celebrex (CX). The effect of an initial CX dose at 6- and 24-h post-PDT was investigated simultaneously. It was observed that hypoxic NPC/CNE2 cells upregulate both COX-2 and VEGF A genes in vitro. In vivo studies, down-regulation of COX-2 and hypoxia inducible factor-1alpha (HIF-1alpha) genes at 24-h post-PDT and bulk tumor ablation at 48-h post-PDT was observed. However, 24-28 days later regrowth was observed. In a combination treatment, 1st CX dose at 6-h post-PDT had the highest tumor control in which tumors were 相似文献
14.
Preimplantation genetic diagnosis principles and ethics 总被引:4,自引:0,他引:4
15.
Life expectancy in British Marfan syndrome populations 总被引:2,自引:0,他引:2
JR Gray AB Bridges RR West L. McLeish AG Stuart JCS Dean MEM Porteous M. Boxer SJ Davies 《Clinical genetics》1998,54(2):124-128
A total of 206 patients with Marfan syndrome were ascertained throughout genetic clinics in Wales and Scotland during the period 1970–1990. There were 45 deaths representing 22% of the cohort. Mean age at death was 45.3 ± 16.5 years. 50% median cumulative survival in the total cohort (n = 206) was 53 years for males and 72 years for females. Multivariate analysis confirmed severity as the best independent indicator of survival. These findings and survival curves will assist in the counselling of British families and individuals with Marfan syndrome. 相似文献
16.
Frataxin is reduced in Friedreich ataxia patients and is associated with mitochondrial membranes 总被引:17,自引:8,他引:17
Campuzano V; Montermini L; Lutz Y; Cova L; Hindelang C; Jiralerspong S; Trottier Y; Kish SJ; Faucheux B; Trouillas P; Authier FJ; Durr A; Mandel JL; Vescovi A; Pandolfo M; Koenig M 《Human molecular genetics》1997,6(11):1771-1780
Friedreich ataxia is a progressive neurodegenerative disorder caused by
loss of function mutations in the frataxin gene. In order to unravel
frataxin function we developed monoclonal antibodies raised against
different regions of the protein. These antibodies detect a processed 18
kDa protein in various human and mouse tissues and cell lines that is
severely reduced in Friedreich ataxia patients. By immunocytofluorescence
and immunocytoelectron microscopy we show that frataxin is located in
mitochondria, associated with the mitochondrial membranes and crests.
Analysis of cellular localization of various truncated forms of frataxin
expressed in cultured cells and evidence of removal of an N-terminal
epitope during protein maturation demonstrated that the mitochondrial
targetting sequence is encoded by the first 20 amino acids. Given the
shared clinical features between Friedreich ataxia, vitamin E deficiency
and some mitochondriopathies, our data suggest that a reduction in frataxin
results in oxidative damage.
相似文献
17.
Recessively inherited L-DOPA-responsive parkinsonism in infancy caused by a point mutation (L205P) in the tyrosine hydroxylase gene 总被引:4,自引:0,他引:4
18.
19.
Y chromosome deletions in azoospermic and severely oligozoospermic men undergoing intracytoplasmic sperm injection after testicular sperm extraction 总被引:11,自引:16,他引:11
Silber SJ; Alagappan R; Brown LG; Page DC 《Human reproduction (Oxford, England)》1998,13(12):3332-3337
Y chromosome deletions encompassing the AZFc region have been reported in
13% of azoospermic men and 7% of severely oligozoospermic men. We examined
the impact of these Y deletions on the severity of testicular defects in 51
azoospermic men undergoing intracytoplasmic sperm injection (ICSI) after
testicular sperm extraction (TESE) and 30 men with severe oligozoospermia
undergoing ICSI after ejaculation of spermatozoa. In addition, five
azoospermic patients shown previously to have Y chromosome deletions
underwent histological evaluation of their previously obtained testis
biopsy specimens. A further 27 azoospermic men underwent TESE-ICSI, but not
Y chromosome DNA testing. Ten of 51 azoospermic men (20%) who underwent
TESE-ICSI and Y-DNA testing were found to be deleted for portions of the Y
chromosome AZFc region. Of these 10, five had spermatozoa retrievable from
the testis, and in two cases the wives became pregnant. Of the 41
azoospermic men with no Y chromosome deletion, 22 (54%) had spermatozoa
retrievable from the testis, and in 12 cases (29%) the wives became
pregnant. Four of 30 (13%) severely oligozoospermic patients were found to
be deleted for AZFc and in three (75%) of these pregnancy was achieved. The
other 26 severely oligozoospermic couples who had no AZFc deletions
underwent ICSI, and 12 (46%) have an ongoing or delivered pregnancy. The
embryo implantation rate was not significantly different for azoospermic
(22%), oligozoospermic (16%), Y-deleted (14%) or Y-intact (18%) men. Of the
total of 19 infertile men who had Y chromosome deletions, 14 had deletions
within Y chromosome intervals 6D-6F, in the AZFc region. Twelve of those 14
had some spermatozoa (however few in number) in the ejaculate or testis.
Five of the Y-deleted men had deletions that extended more proximally on
the Y chromosome, and in none of these could any spermatozoa be observed in
either ejaculate or testis. These results support the concept that, in
azoospermic or oligozoospermic men with Y chromosome deletions limited to
intervals 6D-6F (AZFc), there are generally very small numbers of
testicular or ejaculated spermatozoa. Larger Y deletions, including and
extending beyond the AZFc region and encompassing more Y genes, tend to be
associated with a total absence of testicular spermatozoa. In those cases
where spermatozoa were retrieved, the presence of Y deletions had no
obvious impact on fertilization or pregnancy rate.
相似文献
20.
Queenan JT Jr; Veeck LL; Toner JP; Oehninger S; Muasher SJ 《Human reproduction (Oxford, England)》1997,12(7):1573-1576
In-vitro fertilization patients (n = 15) at risk of ovarian
hyperstimulation syndrome (OHSS) (oestradiol > or =4500 pg/ml on the day
of human chorionic gonadotrophin administration and 25 or more follicles of
intermediate or large size) underwent aspiration of all follicles and
cryopreservation of all fertilized oocytes at the pronuclear stage.
Patients were monitored for up to 2 weeks post- retrieval. Subsequent
transfer of cryopreserved-thawed embryos was performed in programmed cycles
using exogenous oestrogen and progesterone for endometrial preparation. Two
patients (13%) developed OHSS necessitating hospitalization and vaginal
aspiration of ascitic fluid. Two other patients (13%) developed moderate
OHSS requiring ascitic fluid vaginal aspiration in the office setting, with
dramatic improvement of the condition. Subsequent transfer of
cryopreserved- thawed embryos yielded a clinical pregnancy rate of 58% per
transfer and ongoing or delivery rates of 42 and 67% per transfer and per
patient respectively. By eliminating pregnancy potential with
cryopreservation of all prezygotes and examining the pregnancy potential
with subsequent cryopreserved-thawed transfers, it is concluded that OHSS
is reduced, but not eliminated for patients at risk. Subsequent transfer of
cryopreserved-thawed prezygotes in a programmed cycle with exogenous
steroids yields an excellent pregnancy rate.
相似文献