全文获取类型
收费全文 | 26421篇 |
免费 | 1998篇 |
国内免费 | 145篇 |
专业分类
耳鼻咽喉 | 218篇 |
儿科学 | 909篇 |
妇产科学 | 734篇 |
基础医学 | 3463篇 |
口腔科学 | 603篇 |
临床医学 | 2819篇 |
内科学 | 5286篇 |
皮肤病学 | 552篇 |
神经病学 | 2985篇 |
特种医学 | 610篇 |
外科学 | 2585篇 |
综合类 | 243篇 |
一般理论 | 38篇 |
预防医学 | 3365篇 |
眼科学 | 351篇 |
药学 | 1676篇 |
1篇 | |
中国医学 | 45篇 |
肿瘤学 | 2081篇 |
出版年
2024年 | 38篇 |
2023年 | 400篇 |
2022年 | 698篇 |
2021年 | 1256篇 |
2020年 | 799篇 |
2019年 | 1055篇 |
2018年 | 1154篇 |
2017年 | 868篇 |
2016年 | 922篇 |
2015年 | 966篇 |
2014年 | 1285篇 |
2013年 | 1540篇 |
2012年 | 2265篇 |
2011年 | 2261篇 |
2010年 | 1180篇 |
2009年 | 1012篇 |
2008年 | 1476篇 |
2007年 | 1431篇 |
2006年 | 1341篇 |
2005年 | 1169篇 |
2004年 | 1015篇 |
2003年 | 860篇 |
2002年 | 781篇 |
2001年 | 211篇 |
2000年 | 189篇 |
1999年 | 184篇 |
1998年 | 147篇 |
1997年 | 127篇 |
1996年 | 102篇 |
1995年 | 102篇 |
1994年 | 89篇 |
1993年 | 87篇 |
1992年 | 120篇 |
1991年 | 120篇 |
1990年 | 96篇 |
1989年 | 97篇 |
1988年 | 103篇 |
1987年 | 88篇 |
1986年 | 87篇 |
1985年 | 65篇 |
1984年 | 74篇 |
1983年 | 53篇 |
1982年 | 58篇 |
1981年 | 48篇 |
1980年 | 40篇 |
1979年 | 43篇 |
1978年 | 39篇 |
1974年 | 35篇 |
1973年 | 47篇 |
1972年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Daniel A Waschbusch Normand J Carrey Michael T Willoughby Sara King Brendan F Andrade 《Journal of clinical child and adolescent psychology》2007,36(4):629-644
This study examined whether response to behavior modification with and without methylphenidate differed for children with attention-deficit/hyperactivity disorder (ADHD) and conduct problems (CP) depending on the presence of callous/unemotional (CU) traits. Participants were 37 children ages 7 to 12, including 19 with ADHD/CP-only and 18 with ADHD/CP-CU, referred to a university-based summer treatment program. Results showed that ADHD/CP-CU children had worse behavior in the behavior-therapy-only (BT-only) condition, especially on measures of CP, noncompliance, and rule violations, but these differences largely disappeared when medication was added to BT. Children with ADHD/CP-CU were also less likely to be normalized by treatment than were children with ADHD/CP-only. These findings, though tentative, suggest that children with ADHD/CP-CU may not show a sufficient positive response to BT alone and that the combination of medication and BT may be especially important for them. 相似文献
32.
Invariant Visual Responses From Attentional Gain Fields 总被引:5,自引:0,他引:5
33.
34.
Stephen Hunter Terry Gramlich Karen Abbott Vijay Varma 《Genes, chromosomes & cancer》1993,8(3):172-177
Carcinoma of the esophagus shows a strong male predominance and other epidemiologic differences from cancers arising at other sites. In this study, the prevalence of Y chromosome loss in 29 carcinomas of the esophagus and 53 carcinomas arising elsewhere in the aerodigestive tract was assessed by in situ hybridization of formalin-fixed paraffin-embedded tissue sections. Absence of the Y chromosome was defined as (1) negative staining for Y in neoplastic cells with positive staining for Y in immediately adjacent nonneoplastic epithelial and stromal cells, (2) positive staining of neoplastic cells with control probes for chromosomes X and 17, and (3) similar results at different stringencies and levels of protein digestion. According to these criteria, absence of the Y chromosome was observed in 13 of 14 (93%) adenocarcinomas of the esophagus, 8 of 13 (62%) squamous cell carcinomas of the esophagus, and 5 of 53 (9%) carcinomas arising in other sites. For the neoplasms examined, Y chromosome deletion was strongly and selectively associated with carcinomas, particularly adenocarcinomas, of the esophagus (P < .0001). These findings suggest that Y chromosome loss may be pathogenetically significant in these neoplasms. © 1993 Wiley-Liss, Inc. 相似文献
35.
Paramyxoviruses of type 1 (PMV-l) isolated from pigeons were genetically analyzed. A part of the fusion and the matrix protein genes were amplified and sequenced, Typical amino acid sequences associated with virulence were determined at the fusion protein cleavage site in all PMV-1 isolates. All Slovene pigeon PMV-1 strains share high amino acid sequence similarity with other pigeon strains. In the phylogenetic tree, they are clustered together with pigeon PMV-1 isolates with moderate pathogenicity. Phylogenetic analysis obtained from the fusion and the matrix protein gene alignments showed the same branching order. Viruses circulating among pigeons were found to form quite unique lineage of virulent NDV strains. 相似文献
36.
Explored the relationship between vestibular function as measured by duration of postrotary nystagmus and human figure drawing ability in 40 children labeled as learning disabled. Regression analysis revealed that the variable of chronological age shared the most variance with human figure drawing scores. Postrotary nystagmus durations also shared a significant amount of variance with human figure drawing scores, while the variables of IQ and sex were nonsignificant. The results provide additional support for the assertion that some learning-disabled children evidence deficits in vestibular processing ability and that these deficits may affect performance on cognitive-perceptual tasks. 相似文献
37.
The Role of APO-1-Mediated Apoptosis in the Immune System 总被引:12,自引:0,他引:12
38.
Background
Physicians' awareness of their important role in defusing the obesity epidemic has increased. However, the number of family practitioners who treat obesity problems continues to be low. Self-efficacy refers to the belief in one's ability to organize and execute the courses of action required to produce given attainments. Thus, practitioners who judge themselves incapable of managing obesity do not even try. We hypothesized that practitioners' self-efficacy and motivation would be enhanced as a result of participating in an interactive course designed to enrich their knowledge of obesity management. 相似文献39.
40.
Mast cell tryptase and proteinase-activated receptor 2 induce hyperexcitability of guinea-pig submucosal neurons 总被引:5,自引:2,他引:5
David E. Reed Carlos Barajas-Lopez Graeme Cottrell Sara Velazquez-Rocha Olivier Dery Eileen F. Grady Nigel W. Bunnett Stephen J. Vanner 《The Journal of physiology》2003,547(2):531-542
Mast cells that are in close proximity to autonomic and enteric nerves release several mediators that cause neuronal hyperexcitability. This study examined whether mast cell tryptase evokes acute and long-term hyperexcitability in submucosal neurons from the guinea-pig ileum by activating proteinase-activated receptor 2 (PAR2) on these neurons. We detected the expression of PAR2 in the submucosal plexus using RT-PCR. Most submucosal neurons displayed PAR2 immunoreactivity, including those colocalizing VIP. Brief (minutes) application of selective PAR2 agonists, including trypsin, the activating peptide SL-NH2 and mast cell tryptase, evoked depolarizations of the submucosal neurons, as measured with intracellular recording techniques. The membrane potential returned to resting values following washout of agonists, but most neurons were hyperexcitable for the duration of recordings (> 30 min–hours) and exhibited an increased input resistance and amplitude of fast EPSPs. Trypsin, in the presence of soybean trypsin inhibitor, and the reverse sequence of the activating peptide (LR-NH2 ) had no effect on neuronal membrane potential or long-term excitability. Degranulation of mast cells in the presence of antagonists of established excitatory mast cell mediators (histamine, 5-HT, prostaglandins) also caused depolarization, and following washout of antigen, long-term excitation was observed. Mast cell degranulation resulted in the release of proteases, which desensitized neurons to other agonists of PAR2. Our results suggest that proteases from degranulated mast cells cleave PAR2 on submucosal neurons to cause acute and long-term hyperexcitability. This signalling pathway between immune cells and neurons is a previously unrecognized mechanism that could contribute to chronic alterations in visceral function. 相似文献