全文获取类型
收费全文 | 2175篇 |
免费 | 212篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 76篇 |
妇产科学 | 115篇 |
基础医学 | 248篇 |
口腔科学 | 14篇 |
临床医学 | 169篇 |
内科学 | 344篇 |
皮肤病学 | 12篇 |
神经病学 | 227篇 |
特种医学 | 114篇 |
外科学 | 461篇 |
综合类 | 33篇 |
预防医学 | 183篇 |
眼科学 | 26篇 |
药学 | 210篇 |
中国医学 | 1篇 |
肿瘤学 | 160篇 |
出版年
2021年 | 19篇 |
2020年 | 16篇 |
2019年 | 16篇 |
2018年 | 27篇 |
2017年 | 28篇 |
2016年 | 23篇 |
2015年 | 27篇 |
2014年 | 43篇 |
2013年 | 82篇 |
2012年 | 83篇 |
2011年 | 97篇 |
2010年 | 76篇 |
2009年 | 61篇 |
2008年 | 74篇 |
2007年 | 83篇 |
2006年 | 72篇 |
2005年 | 85篇 |
2004年 | 67篇 |
2003年 | 61篇 |
2002年 | 73篇 |
2001年 | 75篇 |
2000年 | 79篇 |
1999年 | 73篇 |
1998年 | 46篇 |
1997年 | 32篇 |
1996年 | 32篇 |
1995年 | 30篇 |
1994年 | 26篇 |
1993年 | 26篇 |
1992年 | 60篇 |
1991年 | 70篇 |
1990年 | 62篇 |
1989年 | 53篇 |
1988年 | 74篇 |
1987年 | 64篇 |
1986年 | 60篇 |
1985年 | 62篇 |
1984年 | 35篇 |
1983年 | 22篇 |
1982年 | 17篇 |
1981年 | 22篇 |
1980年 | 25篇 |
1979年 | 24篇 |
1978年 | 22篇 |
1977年 | 22篇 |
1976年 | 22篇 |
1975年 | 17篇 |
1974年 | 28篇 |
1973年 | 13篇 |
1969年 | 14篇 |
排序方式: 共有2401条查询结果,搜索用时 15 毫秒
31.
Detection of reactive oxygen species (ROS) and apoptosis in human fragmented embryos 总被引:8,自引:2,他引:8
Yang HW; Hwang KJ; Kwon HC; Kim HS; Choi KW; Oh KS 《Human reproduction (Oxford, England)》1998,13(4):998-1002
In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture
environment differs from in-vivo conditions in that the oxygen
concentration is higher, and in such conditions the mouse embryos show a
higher concentration of reactive oxygen species (ROS) in simple culture
media. ROS are believed to cause damage to cell membranes and DNA
fragmentation in somatic cells. This study was conducted to ascertain the
level of H2O2 concentration within embryos and the morphological features
of cell damage induced by H2O2. A total of 62 human oocytes and embryos (31
fragmented, 15 non-fragmented embryos, 16 unfertilized oocytes) was
obtained from the IVF-embryo transfer programme. The relative intensity of
H2O2 concentrations within embryos was measured using
2',7'-dichlorodihydrofluorescein diacetate by Quanti cell 500 fluorescence
imaging and DNA fragmentation was observed with transmission electron
microscopy and an in-situ apoptosis detection kit. The H2O2 concentrations
were significantly higher in fragmented embryos (72.21 +/- 9.62, mean +/-
SEM) compared to non-fragmented embryos (31.30 +/- 3.50, P < 0.05) and
unfertilized oocytes (30.75 +/- 2.67, P < 0.05). Apoptosis was observed
only in fragmented embryos, and was absent in non-fragmented embryos.
Electron microscopic findings confirmed apoptotic bodies and cytoplasmic
condensation in the fragmented blastomeres. We conclude that there is a
direct relationship between increased H2O2 concentration and apoptosis, and
that further studies should be undertaken to confirm these findings.
相似文献
32.
High throughput parallel analysis of hundreds of patient samples for more than 100 mutations in multiple disease genes 总被引:5,自引:0,他引:5
Shuber AP; Michalowsky LA; Nass GS; Skoletsky J; Hire LM; Kotsopoulos SK; Phipps MF; Barberio DM; Klinger KW 《Human molecular genetics》1997,6(3):337-347
As more mutations are identified in genes of known sequence, there is a
crucial need in the areas of medical genetics and genome analysis for
rapid, accurate and cost-effective methods of mutation detection. We have
developed a multiplex allele-specific diagnostic assay (MASDA) for analysis
of large numbers of samples (> 500) simultaneously for a large number of
known mutations (> 100) in a single assay. MASDA utilizes
oligonucleotide hybridization to interrogate DNA sequences. Multiplex DNA
samples are immobilized on a solid support and a single hybridization is
performed with a pool of allele-specific oligonucleotide (ASO) probes. Any
probes complementary to specific mutations present in a given sample are in
effect affinity purified from the pool by the target DNA. Sequence-specific
band patterns (fingerprints), generated by chemical or enzymatic sequencing
of the bound ASO(s), easily identify the specific mutation(s). Using this
design, in a single diagnostic assay, we tested samples for 66 cystic
fibrosis (CF) mutations, 14 beta-thalassemia mutations, two sickle cell
anemia (SCA) mutations, three Tay-Sachs mutations, eight Gaucher mutations,
four mutations in Canavan disease, four mutations in Fanconi anemia, and
five mutations in BRCA1. Each mutation was correctly identified. Finally,
in a blinded study of 106 of these mutations in > 500 patients, all
mutations were properly identified. There were no false positives or false
negatives. The MASDA assay is capable of detecting point mutations as well
as small insertion or deletion mutations. This technology is amenable to
automation and is suitable for immediate utilization for high-throughput
genetic diagnostics in clinical and research laboratories.
相似文献
33.
34.
Dennis M Edelstein K Copeland K Frederick JA Francis DJ Hetherington R Blaser SE Kramer LA Drake JM Brandt ME Fletcher JM 《Neuropsychology》2005,19(4):456-465
Inhibition of return (IOR) refers to an increase in time to react to a target in a previously attended location. Children with spina bifida meningomyelocele (SBM) and hydrocephalus have congenital dysmorphology of the midbrain, a brain region associated with the control of covert orienting in general and with IOR in particular. The authors studied exogenously cued covert orienting in 8- to 19-year-old children and adolescents (84 with SBM and 37 age-matched, typically developing controls). The exogenous cue was a luminance change in a peripheral box that was 50% valid for the upcoming target location. Compared with controls, children with SBM showed attenuated IOR in the vertical plane, a deficit that was associated with midbrain dysmorphology in the form of tectal beaking but not with posterior brain volume loss. The data add to the emerging evidence for SBM deficits in attentional orienting to salient information. 相似文献
35.
Complete amino acid sequence of the basic nucleic acid binding protein of feline leukemia virus 总被引:16,自引:0,他引:16
The complete amino acid sequence of the nucleic acid binding protein p10 of the Rickard strain of feline leukemia virus (FeLV) has been determined. Fragments obtained by enzymatic digestion were purified by reverse-phase liquid chromatography and subjected to semiautomated Edman degradation. FeLV p10 is a basic polypeptide composed of 57 amino acids with Mr = 6604. The structure of p10 is compared to the structures of other retroviral nucleic acid binding proteins, and an analysis of a highly conserved region, the putative binding domain, is presented. 相似文献
36.
J G Copeland M M Levinson R Smith T B Icenogle C Vaughn K Cheng R Ott R W Emery 《JAMA》1986,256(21):2991-2995
In 1985, at the University of Arizona, Tucson, two attempts were made to "bridge" patients from impending death to heart transplantation, using orthotopically positioned total artificial hearts. The first attempt, using an unapproved device on an emergency basis, failed after transplantation because of severe pulmonary edema and Pseudomonas pneumonia and the apparent transmission of a Pseudomonas infection from donor to recipient. The second experience, using a Jarvik-7 device, led to stable support for nine days with one major complication, a reversible neurologic deficit with no associated computed tomographic scan abnormality. This patient survived cardiac transplantation and, after being successfully treated for complications, has made a full recovery and returned to full-time work. 相似文献
37.
Copeland W 《Health care strategic management》1984,2(9):19-23
On January 9, 1982 St. Francis Hospital in Cincinnati, Ohio, closed the doors of its old hospital and moved into a newly constructed facility to be shared with St. George Hospital, also of Cincinnati. This move was the culmination of almost ten years of planning by a Joint Long-Range Planning Committee. This article will detail the processes involved in planning the move, the move itself, and the problems encountered after the move. 相似文献
38.
Guth Sarah McGinnis Ellen Copeland William Hudziak James 《Maternal and child health journal》2022,26(6):1203-1210
Maternal and Child Health Journal - This is a pilot study of the Vermont Family Based Approach, an innovative health promotion program designed to address behavioral health prevention in primary... 相似文献
39.
Yinshi Ren Zhuo Deng Vishal Gokani Michael Kutschke Thomas Wesley Mitchell Olumide Aruwajoye Naga Suresh Adapala Nobuhiro Kamiya Yousef Abu-Amer Harry KW Kim 《Journal of bone and mineral research》2021,36(2):357-368
Legg-Calvé-Perthes disease (LCPD) is a juvenile form of ischemic femoral head osteonecrosis, which produces chronic hip synovitis, permanent femoral head deformity, and premature osteoarthritis. Currently, there is no medical therapy for LCPD. Interleukin-6 (IL-6) is significantly elevated in the synovial fluid of patients with LCPD. We hypothesize that IL-6 elevation promotes chronic hip synovitis and impairs bone healing after ischemic osteonecrosis. We set out to test if anti-IL-6 therapy using tocilizumab can decrease hip synovitis and improve bone healing in the piglet model of LCPD. Fourteen piglets were surgically induced with ischemic osteonecrosis and assigned to two groups: the no treatment group (n = 7) and the tocilizumab group (15 to 20 mg/kg, biweekly intravenous injection, n = 7). All animals were euthanized 8 weeks after the induction of osteonecrosis. Hip synovium and femoral heads were assessed for hip synovitis and bone healing using histology, micro-CT, and histomorphometry. The mean hip synovitis score and the number of synovial macrophages and vessels were significantly lower in the tocilizumab group compared with the no treatment group (p < .0001, p = .01, and p < .01, respectively). Micro-CT analysis of the femoral heads showed a significantly higher bone volume in the tocilizumab group compared with the no treatment group (p = .02). The histologic assessment revealed a significantly lower number of osteoclasts per bone surface (p < .001) in the tocilizumab group compared with the no treatment group. Moreover, fluorochrome labeling showed a significantly higher percent of mineralizing bone surface (p < .01), bone formation rate per bone surface (p < .01), and mineral apposition rate (p = .04) in the tocilizumab group. Taken together, tocilizumab therapy decreased hip synovitis and osteoclastic bone resorption and increased new bone formation after ischemic osteonecrosis. This study provides preclinical evidence that tocilizumab decreases synovitis and improves bone healing in a large animal model of LCPD. © 2020 American Society for Bone and Mineral Research (ASBMR). 相似文献