全文获取类型
收费全文 | 6358篇 |
免费 | 351篇 |
国内免费 | 54篇 |
专业分类
耳鼻咽喉 | 50篇 |
儿科学 | 98篇 |
妇产科学 | 38篇 |
基础医学 | 980篇 |
口腔科学 | 117篇 |
临床医学 | 383篇 |
内科学 | 1724篇 |
皮肤病学 | 78篇 |
神经病学 | 429篇 |
特种医学 | 201篇 |
外科学 | 1181篇 |
综合类 | 30篇 |
预防医学 | 195篇 |
眼科学 | 144篇 |
药学 | 513篇 |
中国医学 | 32篇 |
肿瘤学 | 570篇 |
出版年
2023年 | 35篇 |
2022年 | 61篇 |
2021年 | 144篇 |
2020年 | 58篇 |
2019年 | 99篇 |
2018年 | 110篇 |
2017年 | 100篇 |
2016年 | 100篇 |
2015年 | 106篇 |
2014年 | 129篇 |
2013年 | 219篇 |
2012年 | 335篇 |
2011年 | 369篇 |
2010年 | 230篇 |
2009年 | 202篇 |
2008年 | 344篇 |
2007年 | 432篇 |
2006年 | 364篇 |
2005年 | 375篇 |
2004年 | 401篇 |
2003年 | 329篇 |
2002年 | 361篇 |
2001年 | 159篇 |
2000年 | 150篇 |
1999年 | 128篇 |
1998年 | 104篇 |
1997年 | 79篇 |
1996年 | 62篇 |
1995年 | 46篇 |
1994年 | 54篇 |
1993年 | 47篇 |
1992年 | 107篇 |
1991年 | 102篇 |
1990年 | 81篇 |
1989年 | 93篇 |
1988年 | 87篇 |
1987年 | 73篇 |
1986年 | 64篇 |
1985年 | 56篇 |
1984年 | 50篇 |
1983年 | 51篇 |
1982年 | 22篇 |
1981年 | 22篇 |
1980年 | 19篇 |
1979年 | 31篇 |
1978年 | 25篇 |
1977年 | 23篇 |
1975年 | 16篇 |
1972年 | 14篇 |
1970年 | 14篇 |
排序方式: 共有6763条查询结果,搜索用时 312 毫秒
61.
Newcastle disease virus evolution. I. Multiple lineages defined by sequence variability of the hemagglutinin-neuraminidase gene 总被引:18,自引:0,他引:18
We compared the hemagglutinin-neuraminidase gene sequence among 13 strains of Newcastle disease virus (NDV) isolated over the last 50 years. Although overall homology was remarkably high, the sequence variability demonstrated the existence of at least three distinct lineages, which must have co-circulated for considerable periods. The sequence variability also appears to reflect some accumulation of mutations over time. Strictly correlating with the lineages, the translation products could be classified into three size classes. One class lacked the interchain disulfide bond, and another represented unusual precursor protein of biologically inactive form. The lineages correlated to some extent with virulence and place of isolation of the strains. However, antigenic variations, which were neither cumulative nor progressive, did not correlate with the lineages. These analyses showing multiple lineages were greatly facilitated by a precise calculation of synonymous substitutions, which had been largely free from selective pressures and had occurred frequently and evenly throughout the coding region. 相似文献
62.
63.
Sakaguchi M Toda M Ebihara T Irie S Hori H Imai A Yanagida M Miyazawa H Ohsuna H Ikezawa Z Inouye S 《The Journal of allergy and clinical immunology》2000,106(3):579-584
BACKGROUND: Most children with anaphylaxis to measles, mumps, and rubella vaccines had shown sensitivity to bovine gelatin that was included in the vaccines. Recently, it was found that bovine type I collagen, which is the main content in the gelatin, is a major allergen in bovine gelatin allergy. Fish meat and skin also contain type I collagen. OBJECTIVE: The present study was designed to investigate IgE antibody to fish gelatin in children with fish allergy. METHODS: Serum samples were taken from patients in 3 groups: (1) 10 patients with fish allergy and specific IgE to fish meat; (2) two patients with allergies to both fish meat and bovine gelatin and specific IgE to fish meat and bovine gelatin; and (3) 15 patients with atopic dermatitis and specific IgE to fish meat. Various fish gelatins (type I collagen) were prepared from fish skin. IgE antibody to fish gelatin was analyzed by using ELISA and immunoblotting. RESULTS: Of 10 patients with fish allergy, 3 had specific IgE to fish gelatin. Of two patients with fish allergy and bovine gelatin allergy, all had specific IgE to fish gelatin. Of 15 patients with atopic dermatitis and specific IgE to fish meat, 5 had specific IgE to fish gelatin. Furthermore, IgE from pooled serum of the patients reacted with both the alpha1 and alpha2 chains of fish type I collagen in immunoblots. There is cross-reactivity among gelatins from various fishes, but there is little cross-reactivity between fish and bovine gelatins. CONCLUSION: Some fish-sensitive patients possessed IgE antibody to fish gelatin. Fish gelatin (type I collagen) might be an allergen in subjects with fish allergy. 相似文献
64.
K. Kobayashi T. Suda K. Nan-ya N. Sakaguchi S. Sakaguchi I. Miki 《Inflammation research》2006,55(8):335-341
Objective SKG mice have a point mutation of the zeta-associated protein of 70 kD (ZAP-70) and spontaneously develop a severe polyarthritis
in the conventional condition, whereas they are healthy under the specific pathogen free (SPF) condition. The purpose of this
study was to investigate the cytokine production from splenocytes in SKG mice developing arthritis under the SPF condition.
Material SKG and BALB/c mice were intraperitoneally injected with zymosan A under the SPF condition. Spleen was isolated 1, 2 or 8 weeks
after the intraperitoneal injection of saline or zymosan A. Splenocytes were cultured with concanavalin A. Cytokine production
and proliferation were measured 48 and 72 h after the culture.
Results An intraperitoneal injection of zymosan A induced severe polyarthritis with increased levels of rheumatoid factor and interleukin
6 (IL-6) only in SKG mice. Splenocytes from SKG mice did not proliferate well maybe because of less productivity of IL-2.
The IL-4 production from splenocytes of SKG mice was higher, while interferon-γ production was lower than those of BALB/c
mice. An injection of zymosan A reduced the IL-4 production only in SKG mice.
Conclusions SKG mice do not develop arthritis under the SPF condition possibly because of a low proliferative activity of T cells and
Th2-predominance.
Received 27 December 2005; returned for revision 7 February 2006; accepted by A. Falus 10 March 2006 相似文献
65.
66.
Bernhard U. Zabel Susan L. Naylor Karl-Heinz Grzeschik Alan Y. Sakaguchi 《Somatic Cell and Molecular Genetics》1984,10(1):105-108
Using human-mouse somatic cell hybrids containing different parts of chromosome 6 and a DNA probe of the oncogene (V-myb) of avian myeloblastosis virus (AMV), we regionally mapped by Southern blot techniques the human cellular myb (cmyb) protooncogene to 6q21qter. 相似文献
67.
Saruta J Tsukinoki K Sasaguri K Ishii H Yasuda M Osamura YR Watanabe Y Sato S 《Cells, tissues, organs》2005,180(4):237-244
Human saliva chromogranin A (CgA) is clinically promising as a psychological stress marker. However, expression of CgA is poorly understood in humans, although salivary gland localization of CgA in other mammals, such as rodents and horses, has been demonstrated. In the present study, we investigated the expression and localization of CgA in the human submandibular gland (HSG) using various methods. CgA was consistently localized in serous and ductal cells in HSG, as detected by immunohistochemistry and in situhybridization. Reactivity was stronger in serous cells than in ductal cells. In addition, strong immunoreactivity for CgA was observed in the saliva matrix of ductal cavities. Western blotting gave one significant immunoreactive band of 68 kDa in the adrenal gland, HSG and saliva. Finally, CgA was detected in secretory granules of serous and ductal cells by immunoelectron microscopy. In conclusion, CgA in humans is produced by HSG and secreted into saliva. 相似文献
68.
Shuichi Seki Hiroki Sakaguchi Nobuyoshi Kawakita Atsushi Yanai Tetsuo Kuroki Kenzo Kobayashi 《Virchows Archiv : an international journal of pathology》1993,422(2):133-143
The proliferative activity and ultrastructural characteristics of proliferating biliary epithelial cells were analysed immunohistocytochemically in 39 biopsied liver specimens from patients with acute viral hepatitis, chronic hepatitis and liver cirrhosis using a monoclonal antibody against DNA polymerase (DNA-PA). In acute viral hepatitis with perivenular confluent necrosis, proliferation of typical bile ducts was found frequently in portal areas. In chronic aggressive hepatitis and cirrhosis, ductular proliferation of both typical and atypical forms was found in enlarged portal and periportal areas and in confluent necrotic areas. The number of proliferating biliary epithelial cells that stained positive for DNA-PA was small. There were very few positively stained cells in atypical bile ducts in confluent necrotic areas of cirrhosis. Atypical bile ducts seen in chronic aggressive hepatitis, cirrhosis and acute hepatitis with confluent necrosis were positively stained for both cytokeratins 8 and 19. In cirrhosis, the number of stained biliary epithelial cells in typical bile ducts was larger than the number of such cells in atypical bile ducts (P< 0.01). By electron microscopy, the cells positively stained for DNA-PA were mostly so-called clear cells with irregular nuclei containing coarse nucleoplasm, and a few small cells with scanty cytoplasm and few organelles. 相似文献
69.
Extracellular ATP stimulated histamine release and generation of leukotrience C4 (LTC4) accompanied with the formation of inositol phosphates and a rapid increase in intracellular Ca2+ ([Ca2+]i) in mouse bone marrow-derived cultured mast cells (BMMC). The rank order of histamine-releasing potency of ATP and its metabolites is ATP greater than ADP greater than AMP greater than adenosine. Nonhydrolyzable ATP analog, adenosine-5'-O-[2-thiotriphosphate] (ATP-S) released more histamine from the cells than ATP. On the other hand, simultaneous addition of adenosine analogues at micromolar concentrations potentiated histamine release from the cells induced by ATP (50 microM) or DNP-HSA antigen (0.1 ng/ml) in the following rank order: adenosine greater than AMP much greater than ADP = ATP. Histamine release potentiated by adenosine was blocked by the treatment with pertussis toxin, whereas histamine release induced by ATP was not affected by the toxin, suggesting that extracellular ATP stimulate histamine release from BMMC probably via mechanisms independent of the potentiation of histamine release induced by adenosine. 相似文献
70.