全文获取类型
收费全文 | 738篇 |
免费 | 49篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 12篇 |
妇产科学 | 11篇 |
基础医学 | 70篇 |
口腔科学 | 55篇 |
临床医学 | 81篇 |
内科学 | 44篇 |
皮肤病学 | 19篇 |
神经病学 | 10篇 |
特种医学 | 55篇 |
外科学 | 101篇 |
综合类 | 127篇 |
预防医学 | 28篇 |
眼科学 | 14篇 |
药学 | 126篇 |
中国医学 | 28篇 |
肿瘤学 | 21篇 |
出版年
2023年 | 13篇 |
2022年 | 11篇 |
2021年 | 30篇 |
2020年 | 21篇 |
2019年 | 27篇 |
2018年 | 20篇 |
2017年 | 30篇 |
2016年 | 22篇 |
2015年 | 33篇 |
2014年 | 55篇 |
2013年 | 70篇 |
2012年 | 57篇 |
2011年 | 54篇 |
2010年 | 33篇 |
2009年 | 35篇 |
2008年 | 27篇 |
2007年 | 33篇 |
2006年 | 41篇 |
2005年 | 26篇 |
2004年 | 23篇 |
2003年 | 21篇 |
2002年 | 30篇 |
2001年 | 12篇 |
2000年 | 11篇 |
1999年 | 15篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有819条查询结果,搜索用时 921 毫秒
1.
Biodegradable Polydioxanone Microspheres for Transcatheter Arterial Embolization: Proof of Principle
《Journal of vascular and interventional radiology : JVIR》2020,31(12):2132-2140.e5
PurposeTo evaluate feasibility, embolization success, biodegradability, reperfusion, and biocompatibility of biodegradable microspheres (MS) made from polydioxanone (PDO) for transcatheter arterial embolization.Materials and MethodsUnilateral selective renal embolization of a segmental artery was performed in 16 New Zealand White rabbits with PDO-MS (100–150 μm and 90–315 μm). Animals were randomly assigned to different observation periods and underwent control digital subtraction angiography (DSA) and MR imaging immediately (n = 3), 1 week (n = 2), 4 weeks (n = 2), 8 weeks (n = 2), 12 weeks (n = 5), and 16 weeks (n = 2) after embolization. Kidneys were harvested for macroscopic and histologic analysis of embolization success, biodegradability, and biocompatibility.ResultsEmbolization was technically successful in 15 of 16 animals. One animal died of anesthesia-related circulatory failure. The 100–150 μm MS were injected easily through 3-F catheters; the 90–315 μm MS tended to clog with intermittent catheter obstruction. DSA and MR imaging showed successful target embolization in 13 of 15 animals. In 2 animals, the entire kidney was affected owing to catheter clogging, including a reflux of MS while flushing. Control DSA and MR imaging showed increasing vascular reperfusion with time. Macroscopic and histologic analysis revealed necrosis/infarction in areas in which embolization was achieved. MS were extensively degraded after 16 weeks, and overall inflammatory reaction was mild.ConclusionsBiodegradable PDO-MS induced effective embolization of target vessels while demonstrating good biocompatibility. MS increasingly dissolved at 16 weeks, partial reperfusion started at week 1, and complete reperfusion started at week 8, thus offering possible advantages as a temporary embolic agent. 相似文献
2.
3.
Joseph Leighton 《Methods in Cell Science》1992,14(4):201-207
Summary Formation of epithelial tissues in culture so that they become facsimiles in their structure of such tissues in nature requires procedures that comply with several spatial imperatives: a) three-dimensional growth; b) histophysiologic conditions that provide, concurrently, gradients of maturation and of diffusion of metabolites; and c) growth as layers of cells without free edges. Many steps have been required in the evolution of these methods. Two systems are described here in sufficient detail to serve as a manual. Three-dimensional growth of masses of epithelial tissue is accomplished in matrix culture using Gelfoam sponge and collagen-coated cellulose sponge. Radial gradient culture, a recent development, provides conditions that comply with the requirements of histophysiologic gradients and of epithelial tissue growth in layers without interruption in their continuity. 相似文献
4.
Regional gene therapy for full-thickness articular cartilage lesions using naked DNA with a collagen matrix. 总被引:3,自引:0,他引:3
Paul E Di Cesare Sally R Frenkel Cathy S Carlson Carrie Fang Chuanju Liu 《Journal of orthopaedic research》2006,24(5):1118-1127
A novel gene therapy approach for treating damaged cartilage is proposed that involves placing endotoxin-free cDNA containing the gene for bone morphogenetic protein-2 (BMP-2) in type I collagen sponges and then transferring the naked plasmid DNA construct to the injury site. A full-thickness cartilaginous defect in rabbits implanted with plasmid containing a marker gene (beta-galactosidase) showed expressed protein as detected by immunostaining. At 1 week postimplantation, mesenchymal cells subjacent to the defect had incorporated the implanted naked plasmid DNA and, once transfected, served as local bioreactors, transiently producing the gene product. Plasmids containing the gene for BMP-2 implanted in collagen sponges in cartilage lesions stimulated hyalinelike articular cartilage repair at 12 weeks postimplantation, nearly equivalent in quality to that induced by collagen sponges with recombinant BMP-2 protein. Our approach circumvents the risks of inflammation and immunogenic response associated with the use of viral vectors. Naked plasmid DNA as a vehicle for transferring therapeutic genes has been shown to be effective in a therapeutic model within rabbit articular cartilage and appears to be safe and cost effective. 相似文献
5.
R. Beetz O. Schofer H. Riedmiller R. Schumacher P. Gutjahr 《European journal of pediatrics》1991,150(7):489-492
The occurrence of a Wilms tumour in a 4-year-old girl with bilateral medullary sponge kidney, Beckwith-Wiedemann syndrome and congenital hemihypertrophy demonstrates the close relationship between these disorders. Another six cases from the literature with congenital hemihypertrophy and with medullary sponge kidney are discussed, two of them also developed intra-abdominal neoplasm. 相似文献
6.
《The Knee》2022
BackgroundIn recent years, transcatheter arterial embolization (TAE) using imipenem/cilastatin (IPM/CS) has attracted attention as a treatment for relieving osteoarthritis (OA) pain. However, IPM/CS is not approved by Japanese medical insurance for use as an embolic material. Therefore, it is necessary to develop new embolic materials for TAE to relieve OA pain. The purpose of this study was to develop a swine model of knee arthritis and embolize abnormal neovessels (ANs) using two different embolic materials. We compared the embolic effects and tissue damage in knees.MethodsKnee arthritis was induced by intra-articular injection of papain into 12 knees in six female swine. The swine were divided into two groups of three swine each (six knees per group) for embolization of ANs in the knees with either IPM/CS or soluble gelatin sponge particles (SGSs). Three days after embolization, we compared the embolic effects using angiography and the tissue damage histopathologically.ResultsANs were observed in all 12 knees at 42 days after papain injection. The ANs disappeared and the patent arteries were recanalized 3 days after TAE in all 12 knees. Histopathological evaluation revealed synovitis changes, such as synovial thickening and inflammatory cell infiltration, in all 12 knees. There was no evidence of skin or muscle necrosis in either group. The appearance of ANs, recanalization of the parent arteries, and histopathological outcomes were not significantly different between the two groups.ConclusionSGSs were as safe as IPM/CS for TAE of ANs in this swine model of knee arthritis. 相似文献
7.
Acceleration of bone formation with BMP2 in frame-reinforced carbonate apatite–collagen sponge scaffolds 总被引:2,自引:0,他引:2
Isao Hirata Yuji Nomura Manabu Ito Atsushi Shimazu Masayuki Okazaki 《Journal of artificial organs》2007,10(4):212-217
The development is expected of scaffold biomaterials that feature a shape-maintaining property in addition to high porosity
and large pores that cells can easily invade. To develop a new biodegradable scaffold biomaterial reinforced with a frame,
synthesized carbonate apatite (CO3Ap) was mixed with neutralized collagen gel, and the CO3Ap–collagen mixtures were lyophilized into sponges in a porous hydroxyapatite (HAp) frame ring. X-ray diffraction and Fourier
transform infrared spectroscopy (FT-IR) analyses together with chemical analysis indicated that the synthesized CO3Ap had a crystalline nature and a chemical composition similar to that of bone. Scanning electron microscope (SEM) observation
showed that the CO3Ap–collagen sponge had a sui pore size for cell invasion. In proliferation and differentiation experiments with osteoblasts,
alkaline phosphatase and osteopontin activity were clearly detected. When these sponge–frame complexes with bone morphogenic
protein (rh-BMP2) were implanted beneath the periosteum cranii of rats, significant new bone was created at the surface of
the periosteum cranii after 4 weeks of implantation. These reinforced CO3Ap–collagen sponges with rh-BMP2 are expected to be used as hard tissue scaffold biomaterials for the therapeutic purpose
of the rapid cure of bone defects. 相似文献
8.
J. Bruns P. Kersten W. Lierse M. Silbermann 《Virchows Archiv : an international journal of pathology》1992,421(1):1-8
Summary The purpose of the present study was to examine the fate of autologous perichondrial grafts after transplantation into cartilage lesions in weight-bearing joints. Osteochondral lesions were made in the articular surface of knee joints in 36 sheep. The defects were filled with autologous rib perichondrial grafts which were secured by either collagen sponges (12 animals) or fibrin glue (12 animals). Defects without perichondrial grafts served as controls (12 animals). Following 1 week of immobilization of the operated leg, the plaster was removed and the animals were allowed to move freely. Animals were sacrificed after 4, 8, 12 and 16 weeks. The grafts were removed and investigated histologically. In contrast to weight-bearing areas and control defects, hyaline-like cartilage formation was seen in non-weightbearing areas after 4 weeks. This newly formed cartilage revealed strong metachromasia following staining with acidic toluidine blue and reacted positively with periodic acid-Schiff, indicating de novo synthesis of proteoglycans and glycoproteins. Scanning electron microscopy and examinations with polarized light confirmed a hyaline cartilage-like architecture for the surface area as well as for the fibre orientation of the whole graft. Enzyme histochemistry for alkaline and acid phosphatase activity showed positive reactivity only at the base of the transplants. 相似文献
9.
10.
Phenotypic characterization and analysis of allogeneic T cell responses in ZAP-70 dominant negative transgenic mice 总被引:1,自引:0,他引:1 下载免费PDF全文
R P GLADUE M ALLEN A CUNNINGHAM J GARDNER A M LAQUERRE P A CONNELLY A S SHAW J MCNEISH 《Clinical and experimental immunology》1997,110(3):397-402
Antigen stimulation of T cells results in a series of biochemical events including the interaction of both SH2 domains of ZAP-70 with phosphorylated ITAMS on the T cell receptor. In order to study the physiological relevance of decreasing native ZAP-70–SH2 interaction in vivo, we generated transgenic mice expressing a T cell-specific, dominant negative form of ZAP-70 consisting of only the tandem SH2 domains (ZAP-NC). Phenotypically, these animals had a comparable distribution of lymphocyte subsets in the thymus and spleen compared with the wild-type (WT) controls. However, examination of peripheral blood revealed a slow but progressive decrease in the number of lymphocytes, particularly CD4+ cells, with age (17% reduction by 3 months, 58% reduction by 6 months). Allogeneic responses were then evaluated in vitro as well as in vivo using a subcutaneous sponge matrix implant. Although spleen cells cultured for 4 days in vitro with alloantigen developed normal functional responses, allogeneic responses generated in vivo within a subcutaneous sponge matrix were impaired. This was characterized by a depression in cytotoxic T lymphocyte (CTL) activity, a 82% reduction in the frequency of helper T cells, and a 78% reduction in the capacity of sponge-infiltrating lymphocytes to produce IL-2 in response to secondary antigen stimulation. These results indicate that although overt lymphocyte development and in vitro function were unremarkable, expression of a truncated ZAP-70 affected the in vivo survival of peripheral lymphocytes and altered the in vivo generation of functional activity to alloantigen. 相似文献