全文获取类型
收费全文 | 7850篇 |
免费 | 527篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 147篇 |
儿科学 | 450篇 |
妇产科学 | 187篇 |
基础医学 | 1111篇 |
口腔科学 | 75篇 |
临床医学 | 602篇 |
内科学 | 1792篇 |
皮肤病学 | 304篇 |
神经病学 | 314篇 |
特种医学 | 293篇 |
外科学 | 750篇 |
综合类 | 331篇 |
一般理论 | 1篇 |
预防医学 | 539篇 |
眼科学 | 183篇 |
药学 | 639篇 |
中国医学 | 39篇 |
肿瘤学 | 671篇 |
出版年
2023年 | 52篇 |
2022年 | 97篇 |
2021年 | 180篇 |
2020年 | 107篇 |
2019年 | 125篇 |
2018年 | 145篇 |
2017年 | 127篇 |
2016年 | 171篇 |
2015年 | 205篇 |
2014年 | 256篇 |
2013年 | 350篇 |
2012年 | 438篇 |
2011年 | 430篇 |
2010年 | 302篇 |
2009年 | 287篇 |
2008年 | 364篇 |
2007年 | 336篇 |
2006年 | 294篇 |
2005年 | 290篇 |
2004年 | 248篇 |
2003年 | 233篇 |
2002年 | 216篇 |
2001年 | 208篇 |
2000年 | 186篇 |
1999年 | 150篇 |
1998年 | 140篇 |
1997年 | 120篇 |
1996年 | 124篇 |
1995年 | 96篇 |
1994年 | 111篇 |
1993年 | 98篇 |
1992年 | 117篇 |
1991年 | 108篇 |
1990年 | 112篇 |
1989年 | 111篇 |
1988年 | 120篇 |
1987年 | 107篇 |
1986年 | 91篇 |
1985年 | 94篇 |
1984年 | 63篇 |
1983年 | 55篇 |
1979年 | 71篇 |
1978年 | 55篇 |
1977年 | 47篇 |
1976年 | 56篇 |
1975年 | 50篇 |
1974年 | 51篇 |
1973年 | 51篇 |
1972年 | 61篇 |
1971年 | 44篇 |
排序方式: 共有8428条查询结果,搜索用时 0 毫秒
41.
Rupture of an intra-aortic balloon counterpulsator (IABCP) demands immediate removal. We report a case of thrombus formation within a Datascope IABCP secondary to IABCP rupture, necessitating surgical exploration for removal. There is a disturbing pattern of balloon ruptures with this type of IABCP. 相似文献
42.
Fredrik Ghosh Karl Engelsberg Robert V. English Robert M. Petters 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2007,245(6):835-846
Background The purpose of this study was to explore neuroretinal transplantation in a large animal model of severe retinitis pigmentosa
and to establish graft development, long-term survival, graft-host integration, and effects on the host retina.
Methods Rhodopsin transgenic pigs, aged 6 months, received in one eye a fetal full-thickness neuroretinal sheet in the subretinal
space by means of vitrectomy and retinotomy. Six months postoperatively, eyes were studied in the light microscope and with
immunohistochemical markers. Full-field electroretinography (ERG) was performed at 4 and 6 months.
Results Laminated grafts with well-organized photoreceptors, rod bipolar cells, and Müller cells were found in five of six eyes. Neuronal
connections between graft and host retina were not seen. In the five eyes containing a graft, the number of surviving rods
in the host retina was significantly higher compared with unoperated eyes. The ERG did not reveal any significant difference
in b-wave amplitude between operated and control eyes, but the cone-derived response in operated eyes increased significantly
from 4 to 6 months while the rod response in control eyes decreased significantly.
Conclusions Fetal full-thickness neuroretina can be transplanted safely to an eye with severe retinal degeneration. In their major part,
the transplants develop a normal laminated morphology and survive for at least 6 months. Graft and host retinal neurons do
not form connections. Retinal function in the host is reduced initially by the surgical trauma, but the presence of a well-laminated
graft counteracts this effect and rescues rods from degeneration.
Supported by The Foundation Fighting Blindness (grant# C-NC02-798-0078), The Faculty of Medicine, University of Lund, The
Swedish Research Council, The Princess Margaretas Foundation for Blind Children, The 2nd ONCE International Award for New
Technologies for the Blind. 相似文献
43.
44.
45.
Shu XZ Ghosh K Liu Y Palumbo FS Luo Y Clark RA Prestwich GD 《Journal of biomedical materials research. Part A》2004,68(2):365-375
Hyaluronan (HA) hydrogels resist attachment and spreading of fibroblasts and most other mammalian cell types. A thiol-modified HA (3,3'-dithiobis(propanoic dihydrazide) [HA-DTPH]) was modified with peptides containing the Arg-Gly-Asp (RGD) sequence and then crosslinked with polyethylene glycol (PEG) diacrylate (PEGDA) to create a biomaterial that supported cell attachment, spreading, and proliferation. The hydrogels were evaluated in vitro and in vivo in three assay systems. First, the behavior of human and murine fibroblasts on the surface of the hydrogels was evaluated. The concentration and structure of the RGD peptides and the length of the PEG spacer influenced cell attachment and spreading. Second, murine fibroblasts were seeded into HA-DTPH solutions and encapsulated via in situ crosslinking with or without bound RGD peptides. Cells remained viable and proliferated within the hydrogel for 15 days in vitro. Although the RGD peptides significantly enhanced cell proliferation on the hydrogel surface, the cell proliferation inside the hydrogel in vitro was increased only modestly. Third, HA-DTPH/PEGDA/peptide hydrogels were evaluated as injectable tissue engineering materials in vivo. A suspension of murine fibroblasts in HA-DTPH was crosslinked using PEGDA plus PEGDA peptide, and the viscous, gelling mixture was injected subcutaneously into the flanks of nude mice; gels formed in vivo following injection. After 4 weeks, growth of new fibrous tissue had been accelerated by the sense RGD peptides. Thus, attachment, spreading, and proliferation of cells is dramatically enhanced on RGD-modified surfaces but only modestly accelerated in vivo tissue formation. 相似文献
46.
Ghosh A Misra RK Sharma SP Singh HN Chaturvedi AK 《Indian journal of pathology & microbiology》2000,43(2):107-112
The two sampling techniques were studied in 160 randomly selected cases of superficial swellings in various sites of the body. They were sampled by fine needle aspiration (FNA) and by non-aspiration (NA) (a needle without application of aspiration pressure). Cell samples were cytologically assessed and critically evaluated using five objective parameters. Contamination with blood was more in lymphnode, thyroid and liver lesions in aspiration smears than NA smears and values were statistically significant. Similarly when compared for the degree of cellular trauma and cellular degeneration statistically significant better results were obtained by nonaspiration technique for lymphnode lesions. Regarding amount of cellular material obtained by FNA, statistical significant better results were found for breast lesions only. Statistically significant better maintenance of architecture was observed only for thyroid lesions by NA technique. Better average scores were observed by NA technique for lymphnode and thyroid only. Categorizing all the smears obtained by FNA & NA on the basis of their scores according to predetermined criteria, greater number of diagnostically adequate specimens were obtained by FNA than by NA but the number of diagnostically superior specimens obtained by NA technique was found to be more than that by FNA. The difference was found to be statistically significant. However the number of inadequate smears was also more by NA technique than by FNA technique. 相似文献
47.
Verschuren MC; Blom B; Bogers AJ; Spits H; van Dongen JJ 《International immunology》1998,10(12):1873-1880
Recombination of deltaRec to psiJalpha will delete the TCR delta gene,
which is thought to play an important role in the bifurcation of the TCR
alphabeta versus TCR gammadelta differentiation lineages. We recently
detected a DNA-binding protein in human thymocytes, the so- called PJA-BP,
which recognizes the psiJalpha gene segment and might be one of the factors
involved in the regulation of preferential deltaRec- psiJalpha
rearrangements. We now investigate PJA-BP expression and its correlation
with TCR delta gene deletion in thymocytes. Our electrophoretic mobility
shift assay experiments showed that the PJA-BP is evolutionary conserved in
human, murine and simian thymocytes. Using a large series of human
hematopoietic malignancies (n = 30), we conclude that PJA-BP expression is
thymocyte specific and seems to be restricted to thymocytes committed to
the TCR alphabeta lineage. Analysis of seven well-defined human thymocyte
subpopulations showed that preferential deltaRec-psiJalpha rearrangements
as well as PJA-BP expression can be detected from the immature
CD34-/CD1+/CD3- /CD4+/CD8alpha+beta- thymocyte differentiation stage
onwards. These experiments indicate that expression of PJA-BP in human
thymocytes starts simultaneously with preferential deltaRec-psiJalpha
rearrangements, which supports our hypothesis that PJA-BP is one of the
factors involved in the preferential recombination of deltaRec to
psiJalpha.
相似文献
48.
49.
Chakraborty S Garg P Ramamurthy T Thungapathra M Gautam JK Kumar C Maiti S Yamasaki S Shimada T Takeda Y Ghosh A Nair GB 《Journal of medical microbiology》2001,50(10):879-888
This study identified 17 matching serogroups of Vibrio cholerae belonging to serogroups other than O1 and O139 isolated from human cases and from the environment during a concurrent clinical and environmental study conducted in Calcutta, a cholera endemic area. Isolates within these matching serogroups were compared by various phenotypic and genotypic traits to determine if the environment was the source of the organisms associated with the disease. Clinical strains of V. cholerae were resistant to a greater number of drugs and exhibited multi-drug resistance compared with their environmental counterparts. Except for the presence of the genes for the El Tor haemolysin and the regulatory element ToxR in most of the strains of V. cholerae examined, non-O1, non-O139 V. cholerae strains lacked most of the other known virulence traits associated with toxigenic V. cholerae O1 or O139. Restriction fragment-length polymorphism of virulence-associated genes, ribotypes and DNA fingerprints of strains of matched serogroups showed considerable diversity, although some gene polymorphisms and ribotypes of a few strains of different serogroups were similar. It is concluded that despite sharing the same serogroup, environmental and clinical isolates were genetically heterogeneous and were of different lineages. 相似文献
50.
Acute myelomonocytic leukaemia with pseudo-Chediak-Higashi inclusions in leukaemic blasts report of an unusual case 总被引:1,自引:0,他引:1
Giant inclusions in the blast cells resembling that of Chediak-Higashi syndrome have been reported only in a handful of cases with acute leukaemia. There is a paucity of data on the ultrastructural appearance of such unique light microscopic findings. As many of such patients were reported in late seventies and early eighties [1-4] the outcome of treatment using present day multiple induction/consolidation regimens in such patients has also been rarely reported due to the rarity of such patients. We report here on a patient with acute myeloid leukaemia showing pseudo-Chediak-Higashi inclusions in leukaemic blasts with unusual ultrastructural morphology. 相似文献