全文获取类型
收费全文 | 8430篇 |
免费 | 516篇 |
国内免费 | 141篇 |
专业分类
耳鼻咽喉 | 125篇 |
儿科学 | 151篇 |
妇产科学 | 81篇 |
基础医学 | 1408篇 |
口腔科学 | 142篇 |
临床医学 | 707篇 |
内科学 | 1762篇 |
皮肤病学 | 480篇 |
神经病学 | 620篇 |
特种医学 | 522篇 |
外科学 | 1027篇 |
综合类 | 29篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 305篇 |
眼科学 | 192篇 |
药学 | 871篇 |
中国医学 | 143篇 |
肿瘤学 | 520篇 |
出版年
2024年 | 5篇 |
2023年 | 55篇 |
2022年 | 176篇 |
2021年 | 340篇 |
2020年 | 180篇 |
2019年 | 231篇 |
2018年 | 285篇 |
2017年 | 233篇 |
2016年 | 325篇 |
2015年 | 402篇 |
2014年 | 511篇 |
2013年 | 484篇 |
2012年 | 786篇 |
2011年 | 773篇 |
2010年 | 405篇 |
2009年 | 373篇 |
2008年 | 500篇 |
2007年 | 444篇 |
2006年 | 348篇 |
2005年 | 388篇 |
2004年 | 267篇 |
2003年 | 230篇 |
2002年 | 227篇 |
2001年 | 176篇 |
2000年 | 186篇 |
1999年 | 136篇 |
1998年 | 50篇 |
1997年 | 31篇 |
1996年 | 38篇 |
1995年 | 18篇 |
1994年 | 36篇 |
1993年 | 29篇 |
1992年 | 47篇 |
1991年 | 49篇 |
1990年 | 39篇 |
1989年 | 57篇 |
1988年 | 34篇 |
1987年 | 32篇 |
1986年 | 25篇 |
1985年 | 22篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 16篇 |
1979年 | 17篇 |
1978年 | 8篇 |
1977年 | 9篇 |
1970年 | 4篇 |
1967年 | 4篇 |
排序方式: 共有9087条查询结果,搜索用时 15 毫秒
921.
922.
Molecular remedy of complex I defects: Rotenone-insensitive internal NADH-quinone oxidoreductase of Saccharomyces cerevisiae mitochondria restores the NADH oxidase activity of complex I-deficient mammalian cells 总被引:2,自引:0,他引:2
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Byoung Boo Seo Tomomi Kitajima-Ihara Edward K. L. Chan Immo E. Scheffler Akemi Matsuno-Yagi Takao Yagi 《Proceedings of the National Academy of Sciences of the United States of America》1998,95(16):9167-9171
The NDI1 gene encoding rotenone-insensitive internal NADH-quinone oxidoreductase of Saccharomyces cerevisiae mitochondria was cotransfected into the complex I-deficient Chinese hamster CCL16-B2 cells. Stable NDI1-transfected cells were obtained by screening with antibiotic G418. The NDI1 gene was shown to be expressed in the transfected cells. The expressed Ndi1 enzyme was recognized to be localized to mitochondria by immunoblotting and confocal immunofluorescence microscopic analyses. Using digitonin-permeabilized cells, it was shown that the transfected cells, but not nontransfected control cells, exhibited the electron transfer activities with glutamate/malate as the respiratory substrate. The activities were inhibited by flavone, antimycin A, and KCN but not by rotenone. Added NADH did not serve as the substrate, suggesting that the expressed Ndi1 enzyme was located on the matrix side of the inner mitochondrial membranes. Furthermore, although nontransfected cells could not survive in a medium low in glucose (0.6 mM), which is a substrate of glycolysis, the NDI1-transfected cells were able to grow in the absence of added glucose. When glycolysis is slow, either at low glucose concentrations or in the presence of galactose, respiration is required for cells to survive. The mutant cells do not survive at low glucose or in galactose, but they can be rescued by Ndi1. These results indicated that the S. cerevisiae Ndi1 was expressed functionally in CCL16-B2 cells and catalyzed electron transfer from NADH in the matrix to ubiquinone-10 in the inner mitochondrial membranes. It is concluded that the NDI1 gene provides a potentially useful tool for gene therapy of mitochondrial diseases caused by complex I deficiency. 相似文献
923.
Yehuda Sharf Yoshiteru Seo Uzi Eliav Solang Akselrod Gil Navon 《Proceedings of the National Academy of Sciences of the United States of America》1998,95(8):4108-4112
A technique is described for displaying distinct tissue layers of large blood vessel walls as well as measuring their mechanical strain. The technique is based on deuterium double-quantum-filtered (DQF) spectroscopic imaging. The effectiveness of the double-quantum filtration in suppressing the signal of bulk water is demonstrated on a phantom consisting of rat tail tendon fibers. Only intrafibrillar water is displayed, excluding all other signals of water molecules that reorient isotropically. One- and two-dimensional spectroscopic imaging of bovine aorta and coronary arteries show the characteristic DQF spectrum of each of the tissue layers. This property is used to obtain separate images of the outer layer, the tunica adventitia, or the intermediate layer, the tunica media, or both. To visualize the effect of elongation, the average residual quadrupole splitting <Δνq> is calculated for each pixel. Two-dimensional deuterium quadrupolar splitting images are obtained for a fully relaxed and a 55% elongated sample of bovine coronary artery. These images indicate that the strong effect of strain is associated with water molecules in the tunica adventitia whereas the DQF NMR signal of water in the tunica media is apparently strain-insensitive. After appropriate calibration, these average quadrupolar splitting images can be interpreted as strain maps. 相似文献
924.
925.
926.
Seongho Seo Su J Kim Yu K Kim Jee-Young Lee Jae M Jeong Dong S Lee Jae S Lee 《Journal of cerebral blood flow and metabolism》2015,35(12):2098-2108
In recent years, several linearized model approaches for fast and reliable parametric neuroreceptor mapping based on dynamic nuclear imaging have been developed from the simplified reference tissue model (SRTM) equation. All the methods share the basic SRTM assumptions, but use different schemes to alleviate the effect of noise in dynamic-image voxels. Thus, this study aimed to compare those approaches in terms of their performance in parametric image generation. We used the basis function method and MRTM2 (multilinear reference tissue model with two parameters), which require a division process to obtain the distribution volume ratio (DVR). In addition, a linear model with the DVR as a model parameter (multilinear SRTM) was used in two forms: one based on linear least squares and the other based on extension of total least squares (TLS). Assessment using simulated and actual dynamic [11C]ABP688 positron emission tomography data revealed their equivalence with the SRTM, except for different noise susceptibilities. In the DVR image production, the two multilinear SRTM approaches achieved better image quality and regional compatibility with the SRTM than the others, with slightly better performance in the TLS-based method. 相似文献
927.
Objective:To examine the current trends in surgical-orthodontic treatment for patients with Class III malocclusion using time-series analysis.Materials and Methods:The records of 2994 consecutive patients who underwent orthognathic surgery from January 1, 2004, through December 31, 2015, at Seoul National University Dental Hospital, Seoul, Korea, were reviewed. Clinical data from each surgical and orthodontic treatment record included patient''s sex, age at the time of surgery, malocclusion classification, type of orthognathic surgical procedure, place where the orthodontic treatment was performed, orthodontic treatment modality, and time elapsed for pre- and postoperative orthodontic treatment.Results:Out of the orthognathic surgery patients, 86% had Class III malocclusion. Among them, two-jaw surgeries have become by far the most common orthognathic surgical treatment these days. The age at the time of surgery and the number of new patients had seasonal variations, which demonstrated opposing patterns. There was neither positive nor negative correlation between pre- and postoperative orthodontic treatment time. Elapsed orthodontic treatment time for both before and after Class III orthognathic surgeries has been decreasing over the years.Conclusion:Results of the time series analysis might provide clinicians with some insights into current surgical and orthodontic management. 相似文献
928.
Pancreatic cystic lesions are being diagnosed with increasing frequency owing to the widespread use of cross‐sectional imaging. Although most pancreatic cysts are detected incidentally, they represent a wide spectrum of histopathology, and neoplastic cysts appear to be more prevalent than previously estimated. Some histologic types have malignant potential. Considering the perioperative morbidity associated with surgical resection, deciding whether to operate or observe an indeterminate pancreatic cyst is challenging, and there is a strong clinical need to develop a minimally invasive approach. EUS‐guided pancreatic cyst ablation has been investigated in several clinical trials, and may represent a viable alternative to surgical resection. 相似文献
929.
So Young Park Hyun Jung Kim Kwan Ha Yoo Yong Bum Park Seo Woo Kim Seok Jeong Lee Eun Kyung Kim Jung Hyun Kim Yee Hyung Kim Ji-yong Moon Kyung Hoon Min Sung Soo Park Jinwoo Lee Chang-Hoon Lee Jinkyeong Park Min Kwang Byun Sei Won Lee ChinKook Rlee Ji Ye Jung Yun Su Sim 《Journal of thoracic disease》2015,7(3):356-367