全文获取类型
收费全文 | 19192篇 |
免费 | 891篇 |
国内免费 | 110篇 |
专业分类
耳鼻咽喉 | 281篇 |
儿科学 | 421篇 |
妇产科学 | 212篇 |
基础医学 | 2930篇 |
口腔科学 | 325篇 |
临床医学 | 1138篇 |
内科学 | 4727篇 |
皮肤病学 | 358篇 |
神经病学 | 1365篇 |
特种医学 | 689篇 |
外科学 | 3141篇 |
综合类 | 66篇 |
预防医学 | 535篇 |
眼科学 | 343篇 |
药学 | 1294篇 |
1篇 | |
中国医学 | 43篇 |
肿瘤学 | 2324篇 |
出版年
2023年 | 106篇 |
2022年 | 219篇 |
2021年 | 401篇 |
2020年 | 183篇 |
2019年 | 265篇 |
2018年 | 346篇 |
2017年 | 283篇 |
2016年 | 333篇 |
2015年 | 347篇 |
2014年 | 447篇 |
2013年 | 557篇 |
2012年 | 917篇 |
2011年 | 1059篇 |
2010年 | 575篇 |
2009年 | 495篇 |
2008年 | 852篇 |
2007年 | 960篇 |
2006年 | 973篇 |
2005年 | 971篇 |
2004年 | 993篇 |
2003年 | 960篇 |
2002年 | 1042篇 |
2001年 | 580篇 |
2000年 | 550篇 |
1999年 | 497篇 |
1998年 | 301篇 |
1997年 | 254篇 |
1996年 | 240篇 |
1995年 | 191篇 |
1994年 | 202篇 |
1993年 | 189篇 |
1992年 | 375篇 |
1991年 | 314篇 |
1990年 | 313篇 |
1989年 | 301篇 |
1988年 | 266篇 |
1987年 | 228篇 |
1986年 | 250篇 |
1985年 | 234篇 |
1984年 | 188篇 |
1983年 | 142篇 |
1982年 | 94篇 |
1981年 | 71篇 |
1980年 | 82篇 |
1979年 | 152篇 |
1978年 | 106篇 |
1977年 | 85篇 |
1975年 | 69篇 |
1974年 | 73篇 |
1973年 | 66篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Enhancement of norepinephrine-induced transient contraction in aortic smooth muscle of diabetic mice
Changes in norepinephrine-induced transient contractions in Ca2+-deficient solution were investigated in the aortic smooth muscles of diabetic ALS (alloxan-induced diabetes susceptible) mice. The transient contractions in diabetic mice were significantly larger than those in normal mice. The longer incubation of the muscle preparations in Ca2+-deficient solution made the transient contractions smaller, probably due to the leakage and decrease in norepinephrine-releasable stored Ca2+. The rate of this reduction in contraction was slower in diabetic mice. These results suggest that the leakage of intracellular stored Ca2+ caused by extracellular Ca2+ deficiency is attenuated in diabetic mice, contributing to enhanced norepinephrine-induced transient contractions. 相似文献
82.
Tadashi Yamamoto Itaru Kihara Takashi Morita Takashi Oite 《Pathology international》1978,28(6):859-866
Proliferative glomerulonephritis with proteinuria was induced in Wistar rats by bovine serum albumin (BSA). Rats were first immunized with 1 mg or 2.5 mg of BSA and complete Freund's adjuvant (GFA) and eight weeks later 1 mg of BSA were given intravenously six times a week for four weeks. Immunofluorescence revealed granular deposits of IgG, G3, and BSA in the mesangial area with or without deposition of the same components along the capillary wall. Evaluation of the circulating antibody disclosed an apparent correlation between the level of antibody and histological findings. Rats with an intermediate amount of antibody production developed mesangial widening with mesangial immune deposits and no proteinuria. Rats with a low response developed proliferative glomerulonephritis with immune deposits along the capilary wall as well as in the mesangial area and proteinuria. 相似文献
83.
84.
85.
Shin Nishimura Akio Takahashi Tadashi Narita Tokio Hagiwara Hiroshi Hamana 《Macromolecular chemistry and physics.》1995,196(6):1953-1961
Initiation and propagation reaction mechanisms of the anionic polymerization of hexafluoro-1,3-butadiene (HEBD) were investigated. The initiation reaction with caesium tert-butoxide was found to be completed within 5 min although the reactions were carried out at a much lower temperature than that of the polymerization reaction. The initiation reaction was, therefore, inferred to take place in an anionic fashion by adding the tert-butoxide anion to HFBD. In order to clarify the propagation reaction mechanism of HFBD which yielded a polymer with a polyvinylene structure, the polymerization reactivity of HFBD and hexafluoro-2-butyne (HFBY), the isomerization of HFBD to HFBY, and the structural difference between poly(HFBD) and poly(HFBY) were discussed. In spite of the low yield of HFBY by the isomerization reaction under polymerization conditions, higher yields of poly(HFBD) were obtained. Judging from the X-ray analysis which showed that poly(HFBD) was highly crystalline and poly(HFBY) was amorphous, poly(HFBD) might not be produced by polymerization of HFBY. An addition reaction of the propagating anion to the carbon-2 of the HFBD monomer followed by isomerization at the propagating living end to yield poly[1,2-bis(trifluoromethyl)vinylene] is proposed. 相似文献
86.
Ryuei Maeda Nobuo Ihara Reiko Takada Tadashi Kondo Emyo Nakano Toshiko Yamato 《Pathology international》1971,21(1):151-155
A new vital staining method with neutral red has been established where by cerebral ganglion cells can be stained in vivo . 相似文献
87.
Experimental arthritis induced by continuous infusion of IL-8 into rabbit knee joints. 总被引:1,自引:1,他引:1 下载免费PDF全文
H Endo T Akahoshi A Nishimura M Tonegawa K Takagishi S Kashiwazaki K Matsushima H Kondo 《Clinical and experimental immunology》1994,96(1):31-35
To determine the roles of IL-8 in inflammatory synovitis, examination was made of the results of continuously injecting human recombinant IL-8 into the knee joints of New Zealand while rabbits. Recombinant human IL-8 was infused continuously into the joint cavity at 75 ng/h for 14 days by a polypropylene catheter connected to a mini-osmotic pump implanted in each rabbit. Infiltration of inflammatory cells into joint cavity and histopathological changes in synovial tissue were examined at 7 and 14 days following the start of infusion. The continuous infusion of IL-8 for 14 days led to severe arthritis characterized by apparent erythema and joint pain, the accumulation of leucocytes, infiltration of mononuclear cells in synovial tissue, and marked hypervascularization in the synovial lining layer. IL-8 may be a factor which can contribute to the inflammatory process of chronic arthritis by mediating leucocyte recruitment and hypervascularization in inflamed joints. 相似文献
88.
HeLa cell invasiveness and O antigen of Shigella flexneri as separate and prerequisite attributes of virulence to evoke keratoconjunctivitis in guinea pigs. 总被引:9,自引:7,他引:9 下载免费PDF全文
N Okamura T Nagai R Nakaya S Kondo M Murakami K Hisatsune 《Infection and immunity》1983,39(2):505-513
Many rough mutants selected from isogenic smooth virulent and avirulent strains of Shigella flexneri were examined for virulence, using tissue culture infection and Sereny tests. Many of the rough mutants isolated from a virulent smooth strain were capable of penetrating tissue culture cells but incapable of producing a positive Sereny test. In contrast, we could not obtain from smooth avirulent strains any rough mutants capable of penetrating HeLa cells. Chemical analysis of lipopolysaccharide of some representative rough strains showed several patterns of sugar composition with a range of from Ra to Re chemotypes. There was no correlation between HeLa cell invasiveness and chemotypes of lipopolysaccharides, thus indicating little significance of oligosaccharides of the rough core as well as O antigens in the ability of S. flexneri to penetrate HeLa cells. When these invasive rough strains were given O antigen genes from a smooth avirulent Shigella Hfr strain, most of the transconjugants that expressed O antigens regained the ability to evoke keratoconjunctivitis in guinea pigs. We also examined the chromosomal loci of HeLa cell invasion by transferring carbohydrate fermentation genes of Escherichia coli K-12 Hfr and found two chromosomal loci, the rha and lac-gal regions, which control the ability to penetrate HeLa cells. These results suggested that O antigens and ability to penetrate tissue culture cells are independent and prerequisite attributes of virulence in Shigella flexneri to evoke keratoconjunctivitis in guinea pigs. 相似文献
89.
To obtain human monoclonal anticentromere antibodies, mouse myelomas were fused with unfractionated mononuclear cells from the peripheral blood of a patient diagnosed as having the CREST variant of scleroderma: with only anticentromere antibodies. After a single fusion an heterohybridoma secreting a human antibody specific for nuclear antigens, as detected by indirect immunofluorescence staining, was isolated. The monoclonal antibody secreted by the clone was of the human IgM class. Indirect immunofluorescence staining of the antibody on HEp-2 cells showed multiple nuclear dots or a discrete speckled pattern resembling that of an anticentromere antibody. Immunoblot analysis showed antibody binding to a 33 kD antigen derived from the nuclear protein fraction. Enzyme-immunoassay results clearly showed that the antibody reacted with the chromosomal protein fraction and not calf thymus DNA. 相似文献
90.
Tadashi Terada Yasuni Nakanuma Takeo Matsubara Tetsuo Suematsu 《Pathology international》1988,38(10):1345-1351
The pathology of a rare case of primary diffuse angiosarcoma of the pericardium is reported. Grossly, the heart was entirely encased by the pericardial tumor, and the myocardium was only superficially invaded by the tumor. The tumor tissue extended directly to the mediastinum, where the great vessels were embedded in the tumor. A few minute distant metastases were found only in the bilateral lungs and pulmonary hilar lymph nodes. Microscopically, the tumor tissue was composed of malignant cells forming vascular channels admixed with solid areas. Histo- and immunohistochemically, no mesothelial characteristics were evident. Factor VHI-related antigen and Ulex'europaeus I lectin were positive, implying that the tumor was of vascular origin. Grossly, and in part microscopically, this case resembled malignant diffuse mesothelioma, indicating that pericardial angiosarcoma may sometimes mimick malignant mesothelioma. ACTA PATHOL JPN 38: 1345-1351, 1988. 相似文献