全文获取类型
收费全文 | 2366篇 |
免费 | 156篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 61篇 |
妇产科学 | 48篇 |
基础医学 | 328篇 |
口腔科学 | 91篇 |
临床医学 | 234篇 |
内科学 | 433篇 |
皮肤病学 | 38篇 |
神经病学 | 226篇 |
特种医学 | 73篇 |
外科学 | 201篇 |
综合类 | 23篇 |
一般理论 | 1篇 |
预防医学 | 313篇 |
眼科学 | 67篇 |
药学 | 170篇 |
中国医学 | 9篇 |
肿瘤学 | 181篇 |
出版年
2024年 | 7篇 |
2023年 | 21篇 |
2022年 | 63篇 |
2021年 | 112篇 |
2020年 | 54篇 |
2019年 | 86篇 |
2018年 | 91篇 |
2017年 | 64篇 |
2016年 | 71篇 |
2015年 | 81篇 |
2014年 | 97篇 |
2013年 | 148篇 |
2012年 | 195篇 |
2011年 | 193篇 |
2010年 | 92篇 |
2009年 | 88篇 |
2008年 | 143篇 |
2007年 | 162篇 |
2006年 | 152篇 |
2005年 | 146篇 |
2004年 | 122篇 |
2003年 | 136篇 |
2002年 | 101篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 12篇 |
1998年 | 13篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1969年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1955年 | 2篇 |
1954年 | 2篇 |
1948年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有2530条查询结果,搜索用时 25 毫秒
1.
2.
3.
4.
The aim of this article is to provide clinicians and researchers a comprehensive overview of the development and functions of gesture in childhood and in select populations with developmental language impairments. Of significance is the growing body of evidence that gesture enhances, not hinders, language development. In both normal and impaired populations, gesture and language development parallel each other and share underlying symbolic abilities. Gesture serves several functions, including those of communication, compensation, and transition to spoken language. In clinical practice, gesture may play a valuable role in diagnosis, prognosis, goal selection, and intervention for children with language impairments. Where available, supporting evidence is presented. Needs for additional research on gesture are also highlighted. 相似文献
5.
While two prophylactic HPV vaccines have been proven notably efficacious in clinical trials, the effectiveness of these vaccines at the population level remains to be evaluated. To lay the foundation for understanding the strengths and limitations of different endpoints for future effectiveness research, we present a comprehensive review of HPV-related clinical outcomes, including: (i) HPV type-specific positivity and persistence, (ii) Pap diagnoses (ASC-US, LSIL, and HSIL), (iii) histologic cervical cancer precursor lesions (i.e., CIN1, CIN2, and CIN3), (iv) invasive cervical cancer (ICC), (v) anogenital warts, (vi) recurrent respiratory papillomatosis (RRP), and (vii) other HPV-associated cancers (vulvar, vaginal, anal, penile, and oropharyngeal). While research on the vaccines’ effects on these HPV clinical outcomes in the general population is presently limited, numerous large trials will soon be completed, making a priori discussion of these potential outcomes especially urgent. Furthermore, population level systems to track HPV-associated clinical outcomes may need to be developed for HPV vaccine effectiveness evaluation. 相似文献
6.
Harold P. Schedl Helen D. Wilson Ron L. Horst Karla Christensen Kice Brown 《Nutrition Research》1992,12(12):1541-1547
The circulating concentration of 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] is a physiologic index of enzymatic activity of the renal 1-hydroxylase of 25-hydroxychole-calciferol (25-OH-D3). Hydroxylation of 25-OH-D3 and circulating 1,25-(OH)2D3 are decreased in the streptozotocin diabetic rat. We previously found that activity of another redox enzyme system, cytosolic superoxide dismutase, also decreased in streptozotocin diabetes, can be restored by treatment with glutathione. In the present experiment we tested the effect of glutathione treatment on vitamin D metabolism in control and diabetic rats. Enteral glutathione increased circulating 1,25-(OH)2D3 and decreased 25-OH-D3 in both control and diabetic animals. These results suggest that exogenous glutathione increases 25-OH-D3 1-hydroxylation both under basal conditions in the normal animal and in diabetes-induced depression. 相似文献
7.
Lima JO dos Santos JK Pereira JF de Resende ML de Araújo EF de Queiroz MV 《Current genetics》2003,42(4):236-240
Protoplasts of the pathogenic plant fungus, Crinipellis perniciosa, were transformed to hygromycin B resistance using the pAN7-1 plasmid, which contains the Escherichia coli hph gene under the control of Aspergillus nidulans regulatory sequences. The pAN7-1 plasmid was introduced by PEG/CaCl(2) treatment. Transformation frequencies of 1.6-2.5 transformants/microg of DNA were achieved. About 54% of the transformants were abortive and 40 analyzed transformants were mitotically stable and showed different hygromycin B resistance levels. The presence of the hph gene was checked by PCR in five transformants and the integration of multiple plasmid copies into different genome sites was observed by Southern analysis. This is the first report of a C. perniciosa transformation system and represents an important step for further research into genetic manipulation of this fungal plant pathogen. 相似文献
8.
A/J and C57BL/6J mice behave differently in tests for alcohol preference, open-field activity, defecation in the open field, cricket attacking, and rope climbing. Chimeric mice, i.e., mice containing both A/J cells and C57BL/6J cells, were constructed and tested for these behaviors. Patterns of behavior among A/JC57BL/6J chimeras are such as to suggest that none of these behavior differences is controlled by a single cell or clone and that the same cell population that gives rise to the strain difference in alcohol preference also gives rise to the differences in open-field activity and defecation, while separate cell populations control cricket killing and rope climbing.This research was supported by Research Grants AA 00388 and HD 03015 to M. N. N. and MH 18996 to K. B. Computing assistance was obtained from the Health Sciences Computing Facility, UCLA, supported by NIH Special Research Resources Grant RR-3. 相似文献
9.
The neural mechanism that mediates perceptual filling-in of the blind spot is still under discussion. One hypothesis proposes that the cortical representation of the blind spot is activated only under conditions that elicit perceptual filling-in and requires congruent stimulation on both sides of the blind spot. Alternatively, the passive remapping hypothesis proposes that inputs from regions surrounding the blind spot infiltrate the representation of the blind spot in cortex. This theory predicts that independent stimuli presented to the left and right of the blind spot should lead to neighboring/overlapping activations in visual cortex when the blind-spot eye is stimulated but separated activations when the fellow eye is stimulated. Using functional MRI, we directly tested the remapping hypothesis by presenting flickering checkerboard wedges to the left or right of the spatial location of the blind spot, either to the blind-spot eye or to the fellow eye. Irrespective of which eye was stimulated, we found separate activations corresponding to the left and right wedges. We identified the centroid of the activations on a cortical flat map and measured the distance between activations. Distance measures of the cortical gap across the blind spot were accurate and reliable (mean distance: 6-8 mm across subjects, SD approximately 1 mm within subjects). Contrary to the predictions of the remapping hypothesis, cortical distances between activations to the two wedges were equally large for the blind-spot eye and fellow eye in areas V1 and V2/V3. Remapping therefore appears unlikely to account for perceptual filling-in at an early cortical level. 相似文献
10.