全文获取类型
收费全文 | 6602篇 |
免费 | 304篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 116篇 |
妇产科学 | 69篇 |
基础医学 | 634篇 |
口腔科学 | 145篇 |
临床医学 | 493篇 |
内科学 | 1965篇 |
皮肤病学 | 120篇 |
神经病学 | 361篇 |
特种医学 | 283篇 |
外科学 | 1277篇 |
综合类 | 19篇 |
预防医学 | 134篇 |
眼科学 | 67篇 |
药学 | 398篇 |
中国医学 | 20篇 |
肿瘤学 | 808篇 |
出版年
2023年 | 29篇 |
2022年 | 74篇 |
2021年 | 141篇 |
2020年 | 80篇 |
2019年 | 100篇 |
2018年 | 150篇 |
2017年 | 120篇 |
2016年 | 127篇 |
2015年 | 161篇 |
2014年 | 216篇 |
2013年 | 245篇 |
2012年 | 430篇 |
2011年 | 408篇 |
2010年 | 283篇 |
2009年 | 191篇 |
2008年 | 350篇 |
2007年 | 414篇 |
2006年 | 374篇 |
2005年 | 419篇 |
2004年 | 427篇 |
2003年 | 437篇 |
2002年 | 390篇 |
2001年 | 88篇 |
2000年 | 100篇 |
1999年 | 90篇 |
1998年 | 95篇 |
1997年 | 97篇 |
1996年 | 74篇 |
1995年 | 57篇 |
1994年 | 56篇 |
1993年 | 51篇 |
1992年 | 86篇 |
1991年 | 75篇 |
1990年 | 66篇 |
1989年 | 70篇 |
1988年 | 52篇 |
1987年 | 41篇 |
1986年 | 31篇 |
1985年 | 33篇 |
1984年 | 18篇 |
1983年 | 20篇 |
1982年 | 14篇 |
1981年 | 19篇 |
1980年 | 19篇 |
1979年 | 16篇 |
1978年 | 12篇 |
1976年 | 11篇 |
1974年 | 11篇 |
1970年 | 15篇 |
1969年 | 12篇 |
排序方式: 共有6953条查询结果,搜索用时 203 毫秒
1.
2.
3.
Shigeko Tanaka Minoru Yoshiyama Yukihiro Imanishi Koichi Nakahira Takashi Hanaki Yukari Naito Mizue Imai Masahiro Tanaka 《Magnetic resonance in medical sciences》2006,5(4):207-210
One diagnostic criterion for metabolic syndrome is obesity from the accumulation of visceral fat; others include abdominal circumference and area of visceral fat as measured by computed tomography (CT) at the umbilical level. We evaluated visceral fat using frequency-selective excitation magnetic resonance (MR) imaging SPAIR (spectral attenuation with inversion recovery) water suppression THRIVE (3D T1-high resolution isotropic volume examination). Fifty of 70 slices with 2-mm interval were used to render and measure volume of visceral fat ranging within 10 cm of the umbilicus; the area of visceral fat at the umbilical level was also measured. Imaging was completed using breath hold within 14 s. Image processing was easier than using CT. 相似文献
4.
Kensaku Maeda Kenichi Yasunari Eisuke F Sato Junichi Yoshikawa Masayasu Inoue 《Hypertension research》2003,26(12):999-1006
The involvement of oxidative stress in polymorphonuclear leukocytes (PMN) in the pathogenesis of hypertension remains to be elucidated. We analyzed the generation of reactive oxygen species (ROS) by the circulating and peritoneally infiltrating PMN from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). Flow cytometric analysis revealed that ROS generation by PMN from SHR was higher than that from WKY before (at 6 weeks of age) and after (at 16 weeks of age) the onset of hypertension. In vivo, ROS generation by PMN from SHR, but not that by PMN from WKY, was significantly suppressed by 10-week treatment with 50 mg/kg/day carvedilol, and this treatment did not affect blood pressure. Western blotting analysis revealed that protein kinase C alpha (PKCalpha), but not PKCbetaI or betaII, was activated more strongly in PMN from SHR than in PMN from WKY. Furthermore, expression of p47phox of nicotinamide adenine dinucleotide phosphate oxidase, but not of p67phox, in PMN from SHR was higher than that in PMN from WKY. These results suggest that ROS generation by PMN is principally enhanced in SHR through activation of PKCalpha and p47phox. 相似文献
5.
6.
7.
Ryotaro Wake Masaaki Takeuchi Junichi Yoshikawa Minoru Yoshiyama 《Circulation journal》2007,71(7):1060-1066
BACKGROUND: Gender differences in the predictors of outcome among patients with known or suspected coronary artery disease (CAD) undergoing contrast-enhanced dobutamine stress echocardiography (CE-DSE) have not been completely determined. METHODS AND RESULTS: Follow-up (30+/-17 months) data for 581 men and 309 women with known or suspected CAD who underwent CE-DSE (mean age: 66 years) were obtained. Hard cardiac events included cardiac death and nonfatal myocardial infarction. Total cardiac events included hard cardiac events, unstable angina, congestive heart failure, and late revascularization (>3 months). Cardiac events occurred in 123 male and 50 female patients. Positive results for CE-DSE were associated with worse prognosis in both men and women (2-year total event free rate: 73.5% vs 88.2% in men, p<0.0001, 80.3% vs 91.3% in women, p<0.01). Addition of CE-DSE results, including abnormal left ventricular end-systolic volume response and left ventricular ejection fraction at peak stress <50%, to the clinical and rest echocardiography model provided incremental information for predicting total cardiac events (increase in chi-square value for the model from 60 to 72, p<0.001) in men and (increase in chi-square value for the model from 17 to 32, p<0.001) in women. CONCLUSIONS: CE-DSE provides incremental information for predicting future cardiac events in both men and women. 相似文献
8.
Organ specific ESR features in mouse main organs and ESR application to the model of pancreatic disorders 总被引:1,自引:0,他引:1
A Nonaka T Manabe K Tamura N Asano K Imanishi K Yamaki T Tobe 《Nihon Geka Gakkai zasshi》1990,91(2):169-173
Nine main organs in the mouse were studied by ESR spectroscopy at 77K. Manganese ions were readily detected in the pancreas, small intestine, stomach and kidney. In particular, the pancreas gave strong ESR signals for the transition metal, suggesting that Mn(II) plays an important role in pancreatic function. All organs reveal different ESR spectra indicating organ specificity. C-centered radical, R-OO radical and C0Q10 or ascorbate radical are stable in the tissue. In the brain, heart and pancreas, N-centered radical heme-NO adduct was detected at 6 and 24 h after excision since common process is involved in tissue degeneration and ESR is sensitive to proteolysis and necrosis of tissues. In endotoxemia and/or CDE-diet-induced pancreatic lesions, R-OO radical and Mn(II) ion were detected in the signal at 77K. By the spin-trapping method (DMPO) at 25 degrees C, DMPO-OH adduct and 3-Line and 6-Line were detected in CDE diet-induced acute pancreatitis. These results suggest that damaged pancreatic tissues are in a highly oxidative environment that probably contains oxygen radicals, and that free radicals are considered to play an important role in the development of pancreatic lesions. 相似文献
9.
M Ohsugi Y Imanishi T Teraoka K Nishimura S Nakao 《Journal of nutritional science and vitaminology》1990,36(5):447-456
The biosynthesis of biotin-vitamers from various carbon sources by the members of the Enterobacteriaceae as one of the groups of intestinal bacteria was investigated. The biotin-vitamers synthesized in each case included one or more of dethiobiotin (main product), 7-keto-8-aminopelargonic acid, and biotin. True biotin was shown to be synthesized under aerobic conditions but not under anaerobic conditions by each of several strains belonging to one of the genera, Erwinia, Escherichia, Proteus, and Serratia, and using culture media containing one of galactose, peptone, Polypepton, or casamino acid. In addition, a biotin precursor, pimelic acid, was also synthesized by several bacteria utilizing carbon sources such as maltose, mannose, galactose, peptone, or casamino acid. 相似文献
10.
Hirotaka Inaba Kazuhiko Higuchi Kenji Koseni Haruo Yamauchi Junichi Naganuma 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2005,53(11):587-592
OBJECTIVE: The aortic connector system was used to minimize cerebrovascular complications when performing the proximal anastomosis of vein grafts during coronary artery bypass grafting (CABG). The goal of this study was to investigate the intermediate outcomes of patients undergoing CABG with the aortic connector system. METHODS: The aortic connector was used on nine patients undergoing CABG between November 2002 and July 2003. Intermediate outcomes of the patients were examined, and the results of coronary angiography, which were performed before patient discharge and at least 6 months after discharge, were evaluated. RESULTS: There were no operative deaths or cerebrovascular accidents. One patient died 9 months after discharge, one patient had angina, and the remaining seven patients were asymptomatic. When evaluating the results of angiography performed before patient discharge, two of the 21 distal vein graft anastomoses were occluded (patency rate, 90.5%), but there was no stenosis or occlusion at the proximal anastomoses sites that were performed using the aortic connector. When evaluating the results of the second angiography performed after patient discharge, four of the eight proximal anastomoses were patent, one was completely occluded, two had 90% stenosis and one had 75% stenosis. Further, four of the 18 distal anastomoses were occluded (patency rate, 77.8%). There was no significant difference in graft flow or device size when comparing patients with patent vein grafts and those with stenotic or occluded vein grafts. CONCLUSION: Intermediate outcomes of vein grafting using the aortic connector were suboptimal. Long-term outcome data are forthcoming. 相似文献