全文获取类型
收费全文 | 5076篇 |
免费 | 260篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 39篇 |
儿科学 | 82篇 |
妇产科学 | 60篇 |
基础医学 | 615篇 |
口腔科学 | 61篇 |
临床医学 | 300篇 |
内科学 | 1291篇 |
皮肤病学 | 120篇 |
神经病学 | 473篇 |
特种医学 | 372篇 |
外科学 | 882篇 |
综合类 | 28篇 |
一般理论 | 1篇 |
预防医学 | 135篇 |
眼科学 | 59篇 |
药学 | 300篇 |
中国医学 | 12篇 |
肿瘤学 | 546篇 |
出版年
2023年 | 23篇 |
2022年 | 68篇 |
2021年 | 136篇 |
2020年 | 76篇 |
2019年 | 90篇 |
2018年 | 120篇 |
2017年 | 117篇 |
2016年 | 129篇 |
2015年 | 116篇 |
2014年 | 150篇 |
2013年 | 193篇 |
2012年 | 318篇 |
2011年 | 371篇 |
2010年 | 224篇 |
2009年 | 189篇 |
2008年 | 342篇 |
2007年 | 342篇 |
2006年 | 377篇 |
2005年 | 377篇 |
2004年 | 323篇 |
2003年 | 297篇 |
2002年 | 281篇 |
2001年 | 38篇 |
2000年 | 35篇 |
1999年 | 60篇 |
1998年 | 67篇 |
1997年 | 46篇 |
1996年 | 53篇 |
1995年 | 48篇 |
1994年 | 40篇 |
1993年 | 46篇 |
1992年 | 35篇 |
1991年 | 31篇 |
1990年 | 26篇 |
1989年 | 28篇 |
1988年 | 15篇 |
1987年 | 18篇 |
1986年 | 7篇 |
1985年 | 15篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 14篇 |
1981年 | 12篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1972年 | 3篇 |
1966年 | 3篇 |
排序方式: 共有5376条查询结果,搜索用时 15 毫秒
91.
Takeshi Nakaura Yasunori Nagayama Masafumi Kidoh Shinichi Nakamura Tomohiro Namimoto Kazuo Awai Kazunori Harada Yasuyuki Yamashita 《Japanese journal of radiology》2015,33(9):566-576
Purpose
To evaluate the feasibility of a 20 % reduced contrast dose hepatic arterial phase (HAP) CT for hypervascular hepatocellular carcinoma (HCC) with 100 kVp.Materials and methods
The study included 97 patients with hypervascular HCC who underwent dynamic CT, including HAP scanning. The 54 patients had an estimated glomerular filtration rate (eGFR) of ≥60 were scanned with our conventional 120 kVp protocol. The other 43 patients (eGFR < 60) underwent scans using a tube voltage of 100 kVp and a 20 % reduced contrast dose. We compared the estimated effective dose, image noise, tumor-liver contrast (TLC), and contrast-to-noise ratio (CNR) in the hepatic arterial phase between the two groups using the Student’s t test.Results
Estimated effective dose and image noise were not significantly different between these groups (p = 0.67 and p = 0.20, respectively). The TLC and CNR were significantly higher for the 100 kVp protocol than for the 120 kVp protocol (52.2 HU ± 17.4 vs 40.8 HU ± 18.6, p < 0.01 and 6.8 ± 2.6 vs 5.5 ± 2.4, p = 0.01, respectively).Conclusion
For hepatic arterial phase CT of hypervascular HCC, 100 kVp scan allows a 20 % reduction in the contrast dose without reduction in image quality compared with a standard 120 kVp CT protocol.92.
93.
Lymphomatoid Granulomatosis with Central Nervous System Involvement Successfully Treated with Cyclophosphamide,High‐dose Cytarabine,Dexamethasone, Etoposide,and Rituximab (CHASER therapy) Followed by Brain Irradiation: A Case Study
下载免费PDF全文
![点击此处可从《CNS Neuroscience & Therapeutics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
94.
Crystal structures of two tropinone reductases: Different reaction stereospecificities in the same protein fold 总被引:4,自引:0,他引:4
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)
Keiji Nakajima Atsuko Yamashita Hiroyuki Akama Toru Nakatsu Hiroaki Kato Takashi Hashimoto Junichi Oda Yasuyuki Yamada 《Proceedings of the National Academy of Sciences of the United States of America》1998,95(9):4876-4881
A pair of tropinone reductases (TRs) share 64% of the same amino acid residues and belong to the short-chain dehydrogenase/reductase family. In the synthesis of tropane alkaloids in several medicinal plants, the TRs reduce a carbonyl group of an alkaloid intermediate, tropinone, to hydroxy groups with different diastereomeric configurations. To clarify the structural basis for their different reaction stereospecificities, we determined the crystal structures of the two enzymes at 2.4- and 2.3-Å resolutions. The overall folding of the two enzymes was almost identical. The conservation was not confined within the core domains that are conserved within the protein family but extended outside the core domain where each family member has its characteristic structure. The binding sites for the cofactor and the positions of the active site residues were well conserved between the two TRs. The substrate binding site was composed mostly of hydrophobic amino acids in both TRs, but the presence of different charged residues conferred different electrostatic environments on the two enzymes. A modeling study indicated that these charged residues play a major role in controlling the binding orientation of tropinone within the substrate binding site, thereby determining the stereospecificity of the reaction product. The results obtained herein raise the possibility that in certain cases different stereospecificities can be acquired in enzymes by changing a few amino acid residues within substrate binding sites. 相似文献
95.
Cold pain prolongs gastric emptying of liquid but not solid meal: an electrical impedance tomography (EIT) study 总被引:2,自引:0,他引:2
Nakae Y Kagaya M Takagi R Matsutani Y Horibe H Kondo T 《Journal of gastroenterology》2000,35(8):593-597
Stressful stimuli are reported to affect gastric emptying. However, methods for measuring gastric emptying are, in themselves,
stressful. Electrical impedance tomography (EIT) is a method for measuring gastric emptying noninvasively. We used EIT to
measure gastric emptying of liquid and solid meals to determine the effect of cold pain stress on gastric emptying. EIT (DAS-01P
APT system; University of Sheffield, UK) was carried out in six healthy women (age, 21.6 ± 0.4 [mean ± SD] years) who had
ingested a liquid (potage, 263 g; 139 kcal) or solid (beef patty, 205 g; 435 kcal) test meal. Cold pain stimuli consisted
of repeated immersions of the subject's non-dominant hand into ice water (4°C) for 1 min, with a 15-s recovery period between
immersions, for a total of 20 min. For the control stimulus, water at 37°C was used. The cold pain stimulus was applied immediately
after the ingestion of a test meal. All studies were carried out randomly in each subject at intervals of more than 1 week.
With cold pain, the half emptying time of the liquid meal was significantly greater than that with the control stimulus (47.6
± 26.1 min vs 28.1 ± 10.8 min, P < 0.05). For the solid meal, the half emptying time did not differ between stimuli (101.9 ± 44.8 min with cold pain vs 92.6
± 30.5 min with control stimulus). There were no significant differences in lag time between the liquid and solid meals. Cold
pain stress delayed gastric emptying of liquid but not solid meals.
Received: September 28, 1999 / Accepted: February 25, 2000 相似文献
96.
97.
Yusuke Nakade Tadashi Toyama Kengo Furuichi Shinji Kitajima Yoshiyasu Miyajima Mihiro Fukamachi Akihiro Sagara Yasuyuki Shinozaki Akinori Hara Miho Shimizu Yasunori Iwata Hiroyasu Oe Mikio Nagahara Hiroshi Horita Yoshio Sakai Shuichi Kaneko Takashi Wada 《Clinical and experimental nephrology》2015,19(5):909-917
98.
99.
Kazuhiro Izawa Yasuyuki Hirano Sumio Yamada Koichiro Oka Kazuto Omiya Setsu Iijima 《Circulation journal》2004,68(4):315-320
BACKGROUND: The present study examined the impact of an 8-week cardiac rehabilitation (CR) program on physiological outcomes and health-related quality of life (HRQOL) of patients with acute myocardial infarction (AMI). METHODS AND RESULTS: A total of 124 consecutive AMI patients were divided into a supervised outpatient CR group (n=82) and a non-CR group as a control (n=42). Peak oxygen uptake, handgrip strength, and knee extension muscular strength were used as physiological outcome measures. HRQOL outcomes were assessed by the Medical Outcome Study Short Form 36 (SF-36). CR group patients performed both aerobic exercise and moderate resistance training from 1 month (T1) to 3 months (T2) after AMI onset. Age, sex, body mass index, medications, and ejection fraction were similar in both groups. Significantly greater increases in overall physiological outcomes from T1 to T2 were measured in the CR group compared with those of the non-CR group. There were also significantly greater improvements in 4 of the 8 SF-36 health status subscales (physical functioning, role-physical, general health, and vitality) in the CR group compared with the non-CR group. CONCLUSIONS: Eight weeks of exercise training have specific effects on improvement in HRQOL and physiological outcomes in Japanese patients. 相似文献
100.
Koichiro Higasa Jun-Ichi Manabe Toshitsuga Yubisui Hideki Sumimoto Parichat Pung-amritt Varavarn S. Tanphaichitr & Yasuyuki Fukumaki 《British journal of haematology》1998,103(4):922-930
Hereditary methaemoglobinaemia, caused by deficiency of NADH-cytochrome b5 reductase (b5R), has been classified into two types, an erythrocyte (type I) and a generalized (type II). We analysed the b5R gene of two Thai patients and found two novel mutations. The patient with type II was homozygous for a C-to-T substitution in codon 83 that changes Arg (CGA) to a stop codon (TGA), resulting in a truncated b5R without the catalytic portion. The patient with type I was homozygous for a C-to-T substitution in codon 178 causing replacement of Ala (GCG) with Val (GTG). To characterize effects of this missense mutation, we investigated enzymatic properties of mutant b5R (Ala 178 Val). Although the mutant enzyme showed normal catalytic activity, less stability and different spectra were observed. These results suggest that this substitution influenced enzyme stability due to the slight change of structure. In conclusion, the nonsense mutation led to type II because of malfunction of the truncated protein. On the other hand, the missense mutation caused type I, due to degradation of the unstable mutant enzyme with normal activities in patient's erythrocytes, because of the lack of compensation by new protein synthesis during the long life-span of erythrocytes. 相似文献