全文获取类型
收费全文 | 14167篇 |
免费 | 805篇 |
国内免费 | 125篇 |
专业分类
耳鼻咽喉 | 184篇 |
儿科学 | 266篇 |
妇产科学 | 173篇 |
基础医学 | 2017篇 |
口腔科学 | 463篇 |
临床医学 | 949篇 |
内科学 | 3266篇 |
皮肤病学 | 195篇 |
神经病学 | 1085篇 |
特种医学 | 731篇 |
外国民族医学 | 1篇 |
外科学 | 2158篇 |
综合类 | 339篇 |
一般理论 | 1篇 |
预防医学 | 555篇 |
眼科学 | 323篇 |
药学 | 1002篇 |
中国医学 | 81篇 |
肿瘤学 | 1308篇 |
出版年
2023年 | 94篇 |
2022年 | 180篇 |
2021年 | 308篇 |
2020年 | 186篇 |
2019年 | 202篇 |
2018年 | 269篇 |
2017年 | 222篇 |
2016年 | 264篇 |
2015年 | 309篇 |
2014年 | 377篇 |
2013年 | 413篇 |
2012年 | 702篇 |
2011年 | 738篇 |
2010年 | 401篇 |
2009年 | 379篇 |
2008年 | 584篇 |
2007年 | 662篇 |
2006年 | 644篇 |
2005年 | 616篇 |
2004年 | 672篇 |
2003年 | 703篇 |
2002年 | 676篇 |
2001年 | 517篇 |
2000年 | 548篇 |
1999年 | 474篇 |
1998年 | 196篇 |
1997年 | 162篇 |
1996年 | 126篇 |
1995年 | 110篇 |
1994年 | 111篇 |
1993年 | 104篇 |
1992年 | 347篇 |
1991年 | 307篇 |
1990年 | 269篇 |
1989年 | 248篇 |
1988年 | 247篇 |
1987年 | 225篇 |
1986年 | 187篇 |
1985年 | 165篇 |
1984年 | 133篇 |
1983年 | 122篇 |
1979年 | 71篇 |
1978年 | 52篇 |
1977年 | 59篇 |
1975年 | 64篇 |
1973年 | 52篇 |
1972年 | 59篇 |
1969年 | 49篇 |
1968年 | 62篇 |
1967年 | 64篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Akihiko Usui Fumihiko Murakami Hideki Ooshima Yasuhiro Tomita Katsuhiko Yoshida Michiaki Hibi Mitsuo Kawamura Mitsuya Muras 《Artificial organs》1997,21(7):772-778
Abstract: Cardiopulmonary support (CPS) requires durability of the oxygenator. The life span of the oxygenator is affected by various clinical factors, including patient condition, perfusion condition, and equipment usage. Predictors for the durability of oxygenators were evaluated clinically in this study. Thirty-two patients, who had undergone CPS during the last 3 years in our institute were assigned to this study. Fifty oxygenators had been used (Capiox SX in 19, CB Maxima in 23, and AL-6000 in 8). Significant predictors for the durability of oxygenators were evaluated by nonparametric survival analysis and proportional hazards regression analysis. Univariate regression analysis revealed 6 significant predictors for the life span of oxygenators. These were the oxygenator type, type of centrifugal pump, acidosis with blood pH less than 7.35, base excess less than -5, blood glutamic-oxaloacetic transaminase (GOT) levels greater than 1,000 IU, and blood lactate dehydrogenase (LDH) levels greater than 3,000 IU. After multivariate analysis, there remained only 2 significant predictors. An oxygenator used with a noncoated CPS system (Capiox SX with Capiox EBS) proved to have a significantly shorter life span than one used with a heparin-coated system (CB Maxima or AL-6000 with CB BP-80) (hazards ratio, 3.588, p = 0.0065). Patient conditions, which revealed acidosis with less than -5 of base excess, significantly shortened the life of the oxygenator (hazards ratio, 3.595, p = 0.0188). 相似文献
32.
H Honda H Onitsuka J Murakami K Kaneko S Murayama E Adachi T Kanematsu K Sugimachi K Masuda 《Gastrointestinal radiology》1992,17(3):245-249
The sensitivity, specificity, and accuracy of ultrasonography (US), dynamic incremented computed tomography (CT) with delayed phase imaging, and magnetic resonance imaging (MRI) with or without Gd-DTPA were studied for detecting the characteristic appearances of hepatocellular carcinomas (HCC): fibrous capsules, fibrous septa, and mosaic appearances. Results were prospectively evaluated in 30 patients who subsequently underwent hepatic lobectomies or segmentectomies. Pathologic evaluations of the resected liver specimens demonstrated fibrous capsules in 20 tumors (66.7%), fibrous septa in 13 tumors (43.3%), and mosaic appearances in 19 tumors (63.3%). The accuracies for fibrous capsules were 71.4% (20 of 28) for US, 81.5% (22 of 27) for CT, and 92.3% (24 of 26) for MRI. The accuracies for fibrous septa were 57.1% (16 of 28) for US, 59.3% (16 of 27) for CT, and 73.1% (19 of 26) for MRI. The accuracies for mosaic appearances were 71.4% (20 of 28) for US, 51.9% (14 of 27) for CT, and 69.2% (18 of 26) for MRI. Gd-DTPA administered MRI showed higher accuracies than did conventional MRI for all manifestations. In conclusion, the fibrous capsules of HCCs were readily detected by CT and MRI. Gd-DTPA administration demonstrated an advantage in clarifying fibrous capsules, as well as fibrous septa and mosaic appearances. 相似文献
33.
Cardiac membranes from 26-, 52- and 104-week-old Wistar rats were used to investigate the age-related alterations in the beta-adrenergic receptor-adenylyl cyclase system. The densities and affinities of beta-adrenoceptors did not change with aging. There were no significant changes in the total amount of stimulatory G-protein (Gs), and in Gs activity measured in a reconstitution assay using human platelet membranes. The major isoform of Gs alpha, however, changed from a 45,000 to 52,000 dalton peptide with aging. The total amount of pertussis toxin substrates (Gi2 and Go) decreased significantly with aging. This finding was supported by the fact that pertussis toxin-induced potentiation of adenylyl cyclase activity was markedly reduced in the aged group. The activity of catalytic protein assessed by forskolin-stimulated adenylyl cyclase activity was decreased at 104 weeks. On the other hand, GTP analogue-stimulated adenylyl cyclase activity was significantly potentiated in the same group. These results suggest that the decreased sensitivity to catecholamines observed in aged hearts is mainly due to a dysfunction of catalytic protein, and that decreased Gi activity partially compensates for this catalytic dysfunction. 相似文献
34.
目的 :观察血清保存方法对促甲状腺激素 (TSH)结果的影响。方法 :将甲状腺功能正常、异常患者共 10份血清 ,采用不同血清量、不同条件分组保存后测定 TSH。结果 :保存方法对 TSH结果有一定的影响。结论 :用于 TSH血清的保存量要多、要密封管口、低温保存。 相似文献
35.
Chihaya Maesawa Gen Tamura Yasushi Suzuki Kaoru Ishida Kazuyoshi Saito Ryoichi Satodate 《Cancer science》1992,83(12):1253-1256
For the rapid and sensitive detection of p53 gene mutations in esophageal endoscopic biopsy specimens, we combined cell sorting with the polymerase chain reaction and single-strand conformation polymorphism (PCR-SSCP) analysis. Mutations in exons 5–8 of the p53 gene were investigated by FCR-SSCF analysis using 103 sorted nuclei obtained from each endoscopic biopsy specimen of 16 patients with esophageal cancer. DNAs extracted from their respective surgical specimens were investigated by a conventional method of PCR-SSCP analysis. Mutations in the biopsy specimens were detected in 6 of the 12 aneuploid tumors but in none of the 4 diploid tumors. After tumor cell enrichment by cell sorting, one mutation in exon 8 became apparent, which could not be detected from the surgical specimen by a conventional method of PCR-SSCP analysis. This method should improve the sensitivity of detecting p53 gene mutations, and provides additional information concerning the DNA ploidy pattern in the tumors. 相似文献
36.
S Isaka T Okano J Shimazaki S Murakami T Hara S Kataumi T Yoshida T Nagayama T Wada Y Kitamura 《Nihon Hinyōkika Gakkai zasshi. The japanese journal of urology》1992,83(10):1662-1667
Many reports about the increase of renal cell carcinoma patients have been published in Japan recently, however, the real fluctuations in the total number of patients in relation to the change of population have not been reported yet. Most of the patients with renal cell carcinoma in the last 10 years were examined in Chiba prefecture, which has a population of about five million and 25 active urological offices. Histologically confirmed cases were investigated by sending questionnaire letters. The items were as follows; sex, age, address, occupation, family history, past history, symptoms, examination methods that first detected the tumor, operation date, tumor diameter and clinical stage. Twenty two offices returned answers and 560 cases who lived in Chiba were found to have renal cell carcinoma from 1980 to 1989. Yearly incidence rates per 100,000 persons demonstrated a significant increase from 0.32 to 2.07. Small, asymptomatic and low stage cancers have been increasing rapidly, however, the rate of metastatic disease has not shown any decrease. The main cause of rapid increase seems to be attributed to progress in diagnostic methods and increase of early detection, but the possibility of an increase in some carcinogenic factors can not be ruled out. 相似文献
37.
Y Nakada M Simajiri M Shimabukuro K Oshiro F Nagamine K Murakami G Mimura Y Koyama A Osawa 《Nihon Ronen Igakkai zasshi. Japanese journal of geriatrics》1991,28(6):811-816
An elderly case of idiopathic retroperitoneal fibrosis (IRPF) with bilateral ureteral obstruction was reported. A 74-year-old man was admitted with complaints of general fatigue and loss of appetite. An elastic hard mass with a smooth surface was palpated in the left upper quadrant of the abdomen. Abnormal ESR and CRP were noticed. Abdominal ultrasonography showed both a homoechoic mass which surrounded the aorta in the retroperitoneal space and bilateral hydronephrosis. Computed tomography revealed a retroperitoneal mass involving bilateral ureters. Magnetic resonance imaging demonstrated a mass with a sharp image and signal intensity. Furthermore the morphological relationship between the mass and the ureters and major vessels clearly indicated the characteristics of benign retroperitoneal fibrosis. Based upon the above findings, a diagnosis of IRPF was made. After confirming the histological diagnosis by biopsy, treatment consisting of bilateral ureterolysis, intra-abdominal transposition of ureters and oral administration of prednisolone was performed, resulting in a normalization of laboratory findings. Analysis of 86 previously cases of IRPF reported up to 1990 in Japan, revealed the peak age to be in the 7th decade with predominance in males (males: females = 57:29). 相似文献
38.
S Maeshima H Nakamura M Nishikawa T Murakami T Mitani T Marukawa S Hori T Kozuka M Irimoto 《Clinical imaging》1992,16(2):121-124
Tumors in the area of the adrenal were detected by chance in two patients who underwent a regular physical check-up. On arteriography the tumors were found to be fed by the adrenal artery. The diagnosis was retroperitoneal schwannoma, but in both patients it was difficult to differentiate the schwannoma from an adrenal tumor preoperatively. 相似文献
39.
K Ishino T Murakami H Nakayama M Yamada T Morimoto K Hisamochi T Tanaka Y Senoo S Teramoto 《Acta medica Okayama》1991,45(4):223-231
A biventricular bypass type total artificial heart (BVB-TAH) utilizing two pusher-plate pumps was developed and implanted in a sheep for 48 days with excellent results. A Hall effect sensor was utilized to operate each pump independently with a full stroke at variable rates (VR). With this system, the animal's hemodynamics was kept physiologically, and all metabolic parameters except hemoglobin and hematocrit returned to normal three weeks after implantation. However, signs of infection appeared on the forty-second day, and consequently the animal fell into a state of shock. Even at that time the BVB-TAH maintained circulation by increasing pumping rate automatically. On the forty-eighth day, the animal could not stand and suffered from anuria; the experiment was then terminated after 1,140 h pumping. At autopsy, there was an enlarged heart with an atrophic change, 1,900 ml of pleural effusion, and 3,100ml of ascites fluid. Blood culture taken on the forty-seventh day yielded Acinetobacter calcoaceticus. The BVB-TAH operated in an independent VR mode maintained entire circulation, and has a capability of substituting the native heart function in any situation. 相似文献
40.