全文获取类型
收费全文 | 32029篇 |
免费 | 767篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 396篇 |
儿科学 | 2235篇 |
妇产科学 | 676篇 |
基础医学 | 3446篇 |
口腔科学 | 560篇 |
临床医学 | 1851篇 |
内科学 | 5939篇 |
皮肤病学 | 1159篇 |
神经病学 | 1575篇 |
特种医学 | 1102篇 |
外科学 | 4762篇 |
综合类 | 1015篇 |
一般理论 | 10篇 |
预防医学 | 1486篇 |
眼科学 | 1599篇 |
药学 | 2594篇 |
3篇 | |
中国医学 | 170篇 |
肿瘤学 | 2263篇 |
出版年
2024年 | 178篇 |
2023年 | 201篇 |
2022年 | 490篇 |
2021年 | 934篇 |
2020年 | 533篇 |
2019年 | 649篇 |
2018年 | 827篇 |
2017年 | 556篇 |
2016年 | 823篇 |
2015年 | 761篇 |
2014年 | 1161篇 |
2013年 | 1410篇 |
2012年 | 1994篇 |
2011年 | 2102篇 |
2010年 | 1134篇 |
2009年 | 933篇 |
2008年 | 1569篇 |
2007年 | 1671篇 |
2006年 | 1456篇 |
2005年 | 1355篇 |
2004年 | 1242篇 |
2003年 | 1099篇 |
2002年 | 948篇 |
2001年 | 757篇 |
2000年 | 713篇 |
1999年 | 624篇 |
1998年 | 269篇 |
1997年 | 206篇 |
1996年 | 163篇 |
1995年 | 154篇 |
1994年 | 131篇 |
1993年 | 148篇 |
1992年 | 360篇 |
1991年 | 395篇 |
1990年 | 353篇 |
1989年 | 365篇 |
1988年 | 312篇 |
1987年 | 282篇 |
1986年 | 269篇 |
1985年 | 284篇 |
1984年 | 220篇 |
1983年 | 182篇 |
1979年 | 241篇 |
1978年 | 158篇 |
1977年 | 148篇 |
1976年 | 135篇 |
1975年 | 163篇 |
1974年 | 154篇 |
1973年 | 176篇 |
1972年 | 138篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Yersinia enterocolitica is an enteric bacterium and infections by this organism are mostly foodborne. It has been implicated to cause enterocolitis, terminal ilitis. diarrhoea, mesenteric lymphadenitis and arthritis in man. Due to paucity of information regarding histopathological and specially ultrastructural alterations in tissues affected, this study was planned with mice as the experimental model. Nine pathogenic Y.enterocoliticaisolates were used to infect 80 albino mice by oral and intraperitoneal route. Pathological alterations were studied by light and electron microscopy. Histopathological examination of intestines showed severe edema, purulent enteritis, goblet cell hyperplasia infiltration of mononuclear cells, thickening of mucosa and necrosis of the tips of villi. Liver showed congestion, hepatocellular degeneration and necrosis, atrophy of hepatocytes and microabcesses. The lungs revealed congestion, edema, haemorrhage and purulent ronchopneumonia, while kidneys showed mild necrotic changes and bacterial emboli in glomeruli. Ultrastructural changes were indicative of mitochondrial degeneration and their loss in kidneys, membranous degeneration with formation of myelin figures in lungs and disorganization, disruption and bleb formation of microvilli in intestines. Y.enterocolitica caused significant histopathological and ultrastructural alterations in experimentally infected mice. Variation in pathogenicity of different strains of Y.enterocolitica was also observed. 相似文献
72.
73.
Gupta S Heacock M Perez A Davis PB 《American journal of respiratory cell and molecular biology》2005,33(4):363-370
The polymeric immunoglobulin receptor (pIgR) has been proposed as a therapeutic target, but its potential depends on the efficiency of uptake and trafficking of the receptor ligand. Mouse monoclonal antibodies (Mabs) directed against pIgR, selected for strong binding to secretory component (SC) and secretory IgA (sIgA), were tested in a transcytosis assay in 16HBEo--cells (human bronchial epithelial cell line) transfected with human pIgR. Intracellular trafficking was followed by confocal microscopy. Mabs fell into two classes. For two Mabs, transcytosis from basolateral to apical surface is rapid, unidirectional, and little Mab is retained in the cell. For three Mabs, basolateral to apical transcytosis occurs to a significantly lesser extent, reverse transcytosis is permitted, and some of the Mab is retained in the perinuclear region even after 24 h. When tested for their ability to recognize and immunoprecipitate pIgR with systematic truncations and deletions of the five immunoglobulin (Ig)-like domains, all Mabs bound to the fifth Ig-like domain, but three of them also bound to the C-terminal region of pIgR near the plasma membrane. Different binding sites probably account for the different trafficking of these Mabs and may predict differential therapeutic utility. 相似文献
74.
Avasthi A Sharma A Gupta N Kulhara P Varma VK Malhotra S Mattoo SK 《Journal of affective disorders》2001,64(2-3):145-154
Case records of the patients with major affective disorders (ICD-10 criteria), seen over a 5 year period in a busy clinic in North India were examined for Seasonal Affective Disorder (SAD) as per DSM-III-R criteria. In addition, seasonality of episodes of all affective disorders was also studied. Around 5.67% of the cases (n=44) retrospectively met the DSM-III-R criteria of SAD and predominant pattern was that of summer depression (n=18). There was also a consistent pattern of seasonal mania either in conjunction with seasonal depression (n=18) or in form of seasonal recurrent mania (n=11). None of the cases of depression showed any atypical vegetative features. In cases not meeting criteria for SAD (n=731), there was a trend for peaks for depressive episodes in winter followed by a smaller peak in summer months while manic episodes had peaks towards rainy and winter months. As compared to seasonal patterns of affective disorders in temperate zones, there was a general trend for opposite patterns of seasonality in SAD as well as in non-SAD. The findings are discussed in context of the climatic conditions of North India. 相似文献
75.
76.
77.
78.
There is evidence that the faulty cognitions underlying an individual's playing behavior maintains and supports their gambling behavior. Sixty undergraduate students completed the South Oaks Gambling Screen (SOGS), a measure to assess pathological gambling, and a questionnaire ascertaining the type and frequency of their gambling activities. Sixteen Loto 6/49 tickets were presented to participants and ranked according to their perceived likelihood of being the winning ticket. The numbers on the tickets were categorized as: long sequences (e.g., 1-2-3-4-5-6), patterns and series in a pseudo-psychological order (e.g., 16-21-26-31-36-41), unbalanced (e.g., six numbers from 1-24 or 25-49), and those appearing to be random (e.g., 11-14-20-29-37-43). Verbal protocols of ticket selections were ranked into eight heuristics. Results revealed that for the entire sample the greatest percentage of tickets chosen for the first four selections were "random" tickets. Further, the most commonly cited reason for selecting and changing a lottery ticket was perceived randomness. The results are discussed with reference to the cognitions used when purchasing lottery tickets. 相似文献
79.
J. P. Nigam P. Gupta S. K. Mehta 《Indian journal of otolaryngology and head and neck surgery》1987,39(1):42-43
A case report of the hornification of the nose is presented. It was present since birth, which increased with the advancing age. There were dark pigmented spots all over the body and both the conjunctiva:. Histopathology revealed the nose mass to be a horn like structure and the skin biopsy revealed it to be xeroderma. No case sofar in the literature is available of the hornification of the nose. 相似文献
80.
Macrocarposide, a new isoflavanone c-glucoside from Pterocarpus macrocarpus heart wood 总被引:1,自引:0,他引:1
Macrocarposide has been isolated for the first time as a natural product from the heartwood of PTEROCARPUS MACROCARPUS along with some known compounds. Based on its spectral and chemical evidence, it has been assigned the structure dalbergioidin-6- C-glucoside ( 1). 相似文献