全文获取类型
收费全文 | 33034篇 |
免费 | 1605篇 |
国内免费 | 127篇 |
专业分类
耳鼻咽喉 | 255篇 |
儿科学 | 503篇 |
妇产科学 | 415篇 |
基础医学 | 4438篇 |
口腔科学 | 1002篇 |
临床医学 | 2261篇 |
内科学 | 8321篇 |
皮肤病学 | 741篇 |
神经病学 | 2383篇 |
特种医学 | 1234篇 |
外科学 | 5420篇 |
综合类 | 127篇 |
一般理论 | 1篇 |
预防医学 | 1145篇 |
眼科学 | 614篇 |
药学 | 2297篇 |
中国医学 | 65篇 |
肿瘤学 | 3544篇 |
出版年
2021年 | 580篇 |
2020年 | 278篇 |
2019年 | 390篇 |
2018年 | 530篇 |
2017年 | 426篇 |
2016年 | 506篇 |
2015年 | 507篇 |
2014年 | 694篇 |
2013年 | 855篇 |
2012年 | 1353篇 |
2011年 | 1539篇 |
2010年 | 805篇 |
2009年 | 773篇 |
2008年 | 1349篇 |
2007年 | 1466篇 |
2006年 | 1521篇 |
2005年 | 1511篇 |
2004年 | 1386篇 |
2003年 | 1487篇 |
2002年 | 1540篇 |
2001年 | 1439篇 |
2000年 | 1444篇 |
1999年 | 1245篇 |
1998年 | 457篇 |
1997年 | 333篇 |
1996年 | 307篇 |
1995年 | 262篇 |
1994年 | 234篇 |
1993年 | 232篇 |
1992年 | 911篇 |
1991年 | 805篇 |
1990年 | 729篇 |
1989年 | 740篇 |
1988年 | 675篇 |
1987年 | 686篇 |
1986年 | 602篇 |
1985年 | 570篇 |
1984年 | 366篇 |
1983年 | 311篇 |
1982年 | 158篇 |
1979年 | 246篇 |
1978年 | 181篇 |
1977年 | 152篇 |
1975年 | 155篇 |
1974年 | 155篇 |
1973年 | 169篇 |
1970年 | 152篇 |
1969年 | 154篇 |
1968年 | 147篇 |
1967年 | 155篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
991.
Okayama N Hamanaka Y Suehiro Y Hasui Y Nakamura J Hinoda Y 《The journals of gerontology. Series A, Biological sciences and medical sciences》2005,60(12):1525-1529
Increased inflammatory activity is known to accompany aging. Single nucleotide polymorphisms of inflammatory mediator genes might therefore affect the aging process. Relation of eight SNPs (tumor necrosis factor-alpha [TNF-alpha] -1031 T/C, interleukin-10 [IL-10] -819 T/C, IL-1beta -511 C/T, IL-6 -634 C/G, IL-18 -607 A/C, transforming growth factor-beta [TGF-beta] +869 C/T, matrix metalloproteinase-1 [MMP-1] -1607 1G/2G, and MMP-3 -1171 5A/6A) with age or gender was evaluated in 500 Japanese persons (mean age: 56.7 years old, range: 19-100) by the chi-square test. There was a significant association of IL-10 -819 T/C with age (p =.0026). The association remained significant after multivariate logistic regression analysis (odds ratio for an age interval for 1 year, 1.009; 95% CI, 1.002-1.016). Furthermore, the genotype distribution of IL-10 -819 T/C was completely consistent with that of -592 A/C. These data suggest that IL-10 -819 T/C and -592 A/C may be a promising candidate for an aging-related gene in a Japanese population. 相似文献
992.
993.
Apoptosis and p53 expression in chondrocytes relate to degeneration in articular cartilage of immobilized knee joints 总被引:9,自引:0,他引:9
Okazaki R Sakai A Ootsuyama A Sakata T Nakamura T Norimura T 《The Journal of rheumatology》2003,30(3):559-566
OBJECTIVE: We have reported that articular cartilage showed early stage degeneration at 7 and 14 days after immobilization, moderate degeneration at 28 days, and severe degeneration at 42 days in rabbits. To test whether apoptosis occurs in association with p53 expression in chondrocytes during the process of articular cartilage degeneration, we investigated the degree of cartilage degeneration, the frequency of apoptotic cells, and the levels of p53 mRNA in rabbits and mice after knee immobilization. METHODS: Right knees of male Japanese white rabbits were immobilized in full extension with fiberglass casts for up to 42 days. Similarly, right knees of male p53 wild-type [p53 (+/+)] and p53 null [p53 (-/-)] mice were immobilized in full extension with bandage tape for up to 84 days. Apoptotic cells were confirmed by TUNEL staining on the sections of knee joints. Total RNA of articular chondrocytes obtained from Day 0 or immobilized knees was analyzed semiquantitatively by RT-PCR using specific primers for p53. RESULTS: Articular cartilage degenerated after immobilization of p53 (+/+) mouse knees, but not after immobilization of p53 (-/-) knees. Apoptotic cells were observed in articular cartilage in the femur and tibia of rabbits and p53 (+/+) mice after immobilization. However, only a few apoptotic cells were observed at the same sites in p53 (-/-) mice. In RT-PCR analysis, the levels of p53 mRNA obtained from immobilized groups were significantly higher than those of Day 0 groups in rabbit and p53 (+/+) mouse knees. CONCLUSION: Apoptosis and p53 expression in chondrocytes relate to degeneration in articular cartilage of immobilized knee joints. 相似文献
994.
Soejima H Suefuji H Miyamoto S Kajiwaram I Kojima S Hokamaki J Sakamoto T Yoshimura M Nakamura H Yodoi J Ogawa H 《Clinical cardiology》2003,26(12):583-587
BACKGROUND AND HYPOTHESIS: Thioredoxin is an important biomarker for oxidative stress. We investigated whether thioredoxin levels were elevated in patients with acute myocardial infarction (AMI) and were associated with the results of coronary reperfusion. METHODS: The present study determined plasma thioredoxin levels in 51 patients with AMI, 30 patients with stable exertional angina (SEA), and 30 patients with chest pain syndrome (CPS). Plasma sampling was performed on admission, at 12 h, 1 week, 2 weeks, and 4 weeks in patients with AMI, and after admission in patients with SEA and CPS. RESULTS: Plasma thioredoxin levels on admission were higher in patients with AMI than in those with SEA and CPS. Plasma thioredoxin levels in patients with AMI were decreased in 12 h without further change thereafter. However, thioredoxin levels in patients with AMI remained higher than in those with SEA. In multivariate analysis, higher levels of thioredoxin on admission were a risk factor for failure in emergent reperfusion therapy in patients with AMI independent of other factors. CONCLUSION: Plasma thioredoxin levels are elevated in patients with AMI, and higher thioredoxin levels may predict subsequent failed coronary reperfusion therapy in patients with AMI. 相似文献
995.
996.
Tadanori Aizawa MD Ken Ogasawara MD Fumitaka Nakamura MD Akira Hirosaka MD Tohru Sakuma MD Kazuyuki Nagashima MD Kazuzo Kato MD 《The American journal of cardiology》1989,63(21):J75-J79
In patients in whom dynamic coronary obstruction plays a predominant role in the pathogenesis of angina pectoris, dilatation of large coronary arteries and relief of coronary spasm account for the main mechanism of action of antianginal drugs. In this study, the acute vasodilating effects of nicorandil, a newly developed antianginal drug, were assessed in 10 patients who had spontaneous and ergonovine-evoked coronary spasms. The prompt, complete relief of both spontaneous and evoked coronary spasms was obtained in all of 10 patients with nicorandil. The coronary spasmolytic effect of nicorandil in the present series is thus considered to be beneficial to the treatment of coronary spasm. 相似文献
997.
Analysis of hepatofugal flow in portal venous system using ultrasonic Doppler duplex system 总被引:9,自引:0,他引:9
T Kawasaki F Moriyasu O Nishida N Ban T Nakamura T Tamada T Kimura Y Yamashita S Ono H Uchino 《The American journal of gastroenterology》1989,84(8):937-941
Blood flow directions of the portal trunk, splenic vein, and superior mesenteric vein were studied using an ultrasonic Doppler duplex system in 146 healthy adults, 132 patients with liver cirrhosis, 76 with hepatocellular carcinoma, 32 with idiopathic portal hypertension, 134 with chronic hepatitis, 18 with acute hepatitis, and 142 with other diseases. Spontaneous hepatofugal flow in one or more of the three vessels examined was detected in 14 patients. Spontaneous hepatofugal flow in the portal trunk was detected in three patients with liver cirrhosis. In two of these three patients, the hepatofugal flow in the portal trunk disappeared after medication. This is interesting, since hepatofugal flow may, in fact, be more common than we suspected in patients who, because of the severity of their disease, are not able to undergo invasive examination. Postoperative hepatofugal flow in the portal system was detected in 20 of 71 cases: 15/17 patients after interposition mesocaval shunting, 2/17 after distal splenorenal shunting, 2/31 after splenectomy, and 1/6 after splenic artery occlusion with steel coils. In more than half the cases of interposition mesocaval shunting (9/17 patients), blood flow in the portal trunk was hepatofugal. However, hepatopetal blood flow in the portal trunk was maintained in most cases of distal splenorenal shunting (13/17), showing the merits of this technique as a selective portosystemic shunt operation. 相似文献
998.
O Nishida F Moriyasu T Nakamura N Ban K Miura M Sakai H Uchino T Miyake 《Gastroenterology》1986,90(4):1042-1046
Blood flow volume of the portal venous system of 3 patients with splenic artery aneurysm, an uncommon disease, was measured using an ultrasonic duplex system. A huge increase in splenic blood flow volume was found in each case. A large portasystemic shunt through which the portal blood flowed hepatofugally was present in 2 cases. We suspect the shunt is partially responsible for an increase in splenic blood flow volume, which would lead to the formation of splenic artery aneurysm together with portal hypertension. 相似文献
999.
Subacute cor pulmonale due to tumor embolism 总被引:1,自引:0,他引:1
Nakamura H Adachi H Sudoh A Yagyu H Kishi K Oh-ishi S Kusama H Hashimoto T Matsuoka T 《Internal medicine (Tokyo, Japan)》2004,43(5):420-422
We describe a patient wih subacute cor pulmonale caused by tumor emboli in the lungs. A 64-year-old female suffering from a subacute progressive cough and shortness of breathing died of severe pulmonary hypertension seven days after admission. Neither chest CT scans nor lung perfusion scintigraphy showed any abnormal findings. Microscopic examination after an autopsy revealed diffuse intravascular tumor emboli occluding not only the small pulmonary arteries and arterioles, but also the lymphatic vessels, which were suggested to be metastases of a breast carcinoma resected five years previously. Thus, pulmonary tumor embolism should be considered in the differential diagnosis of primary pulmonary hypertension, particularly in patients with a past history of cancers. 相似文献
1000.