全文获取类型
收费全文 | 23775篇 |
免费 | 1376篇 |
国内免费 | 192篇 |
专业分类
耳鼻咽喉 | 145篇 |
儿科学 | 653篇 |
妇产科学 | 726篇 |
基础医学 | 2898篇 |
口腔科学 | 363篇 |
临床医学 | 1624篇 |
内科学 | 5450篇 |
皮肤病学 | 554篇 |
神经病学 | 2059篇 |
特种医学 | 851篇 |
外国民族医学 | 2篇 |
外科学 | 3756篇 |
综合类 | 188篇 |
一般理论 | 8篇 |
预防医学 | 1492篇 |
眼科学 | 411篇 |
药学 | 1574篇 |
中国医学 | 91篇 |
肿瘤学 | 2498篇 |
出版年
2023年 | 136篇 |
2022年 | 383篇 |
2021年 | 599篇 |
2020年 | 396篇 |
2019年 | 455篇 |
2018年 | 639篇 |
2017年 | 428篇 |
2016年 | 509篇 |
2015年 | 646篇 |
2014年 | 825篇 |
2013年 | 1125篇 |
2012年 | 1561篇 |
2011年 | 1551篇 |
2010年 | 1034篇 |
2009年 | 893篇 |
2008年 | 1390篇 |
2007年 | 1392篇 |
2006年 | 1300篇 |
2005年 | 1223篇 |
2004年 | 1215篇 |
2003年 | 1040篇 |
2002年 | 1067篇 |
2001年 | 583篇 |
2000年 | 517篇 |
1999年 | 484篇 |
1998年 | 265篇 |
1997年 | 196篇 |
1996年 | 200篇 |
1995年 | 188篇 |
1994年 | 161篇 |
1993年 | 145篇 |
1992年 | 291篇 |
1991年 | 264篇 |
1990年 | 257篇 |
1989年 | 243篇 |
1988年 | 195篇 |
1987年 | 159篇 |
1986年 | 165篇 |
1985年 | 145篇 |
1984年 | 129篇 |
1983年 | 102篇 |
1982年 | 59篇 |
1981年 | 57篇 |
1979年 | 66篇 |
1975年 | 41篇 |
1974年 | 49篇 |
1973年 | 42篇 |
1969年 | 40篇 |
1968年 | 45篇 |
1967年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Aldo Cunha Medeiros Irami Araújo Filho Vítor Brasil Medeiros Laíza Araújo Mohana Pinheiro Flávio Henrique Miranda Araújo Freire Italo Medeiros Azevedo José Brand?o-Neto 《Journal of investigative surgery》2007,20(1):41-48
After total gastrectomy, the ileocecal graft may act as a reservoir and protect against reflux but give rise to transposition of the ileum and cause possible changes in bile acid metabolism and nutrition. This study compared the ileocecal graft and jejunal pouch. Male Wistar rats weighing 265 +/- 22 g were submitted to sham operation (S), ileocecal interposition graft (IIG), and jejunal pouch interposition graft (JP) after total gastrectomy. Eight weeks later, the esophagus was examined for evidence of esophagitis. Nutritional biochemistry and weight profile were documented preoperatively and 8 weeks after surgery. The oral glucose tolerance test was performed. Thirty-three rats were operated on and 30 survived for 8 weeks. Esophagitis occurred in seven JP rats. Body weight was significantly higher in IIG than in JP rats (p < .05). Normal glucose tolerance to intragastric glucose load was observed in sham and operated rats. JP rats had a significant decrease in serum albumin, glucose, transferrin, hemoglobin, iron, folate, and calcium, compared to sham (p < .05). Cobalamine was significantly lower in IIG rats than in JP rats (p < .05). In the IIG and JP groups, serum/hepatic total bile acid did not differ significantly from preoperative and sham values. In conclusion, the IIG interposition graft in rats prevented esophagitis, preserved nutrition, and did not interfere with enterohepatic total bile acid circulation. 相似文献
32.
33.
C Pelucchi E Pira G Piolatto M Coggiola P Carta C La Vecchia 《Annals of oncology》2006,17(7):1039-1050
BACKGROUND: In 1997, a Monograph from the International Agency for Research on Cancer (IARC) classified occupational exposure to crystalline silica as carcinogenic to humans. Large amounts of epidemiological data have been published subsequently. METHODS: We conducted a systematic review of epidemiological investigations on silica exposure and lung cancer risk published after the IARC Monograph, including 28 cohort, 15 case-control and two proportionate mortality ratio (PMR) studies. These were identified in the available literature. RESULTS: The pooled RR of lung cancer, calculated using random effects models, from all cohort studies considering occupational exposure to silica was 1.34. The RRs were 1.69 in cohort studies of silicotics only, 1.25 in studies where silicosis status was undefined and 1.19 among non silicotic subjects. The pooled RR was 1.41 for all case-control studies. The RRs were 3.27 in case-control studies of silicotics only, 1.41 in studies where silicosis status was undefined and 0.97 among non silicotic subjects. The RR was 1.24 for PMR studies. CONCLUSIONS: In this re-analysis, the association with lung cancer was consistent for silicotics, but the data were limited for non silicotic subjects and not easily explained for undefined silicosis status workers. This leaves open the issue of dose-risk relation and pathogenic mechanisms and supports the conclusion that the carcinogenic role of silica per se in absence of silicosis is still unclear. 相似文献
34.
Vincenzo Arizza Nicol Parrinello Sandra Schimmenti 《Developmental and comparative immunology》1991,15(4):219-226
-Lactose specific lectins are released from Phallusia mamillata hemocytes during short-term cultures. The molecular weight of the subunits, the immunological cross-reaction and the sugar specificity suggest that the released lectins are similar to those isolated from the sonicated hemocytes. Because lectin release appears to take place independently of active protein synthesis, the possibility exists that lectins are pre-formed, stored in hemocytes and released when in vitro conditions stimulate the cells. 相似文献
35.
Vincenzo La Milia Salvatore Di Filippo Monica Crepaldi Simeone Andrulli Lucia Del Vecchio Pietro Scaravilli Giovambattista Virga Francesco Locatelli 《Nephrology, dialysis, transplantation》2004,19(7):1849-1855
BACKGROUND: Sodium removal (NaR) may have a major impact on the survival of peritoneal dialysis patients. The dialysate/plasma sodium concentration ratio (D/P(Na)) is an indirect index of transcellular water transport by aquaporin channels, and thus of ultrafiltration. Sodium concentration can be assessed by means of flame photometry (F), and direct (D-ISE) or indirect ion-selective electrodes (I-ISE), but these methods have different properties. I-ISE is being used increasingly in clinical laboratories. The aim of this study was to evaluate NaR and D/P(Na) using the three different measurement methods. METHODS: We performed peritoneal equilibration tests (PETs) in 44 peritoneal dialysis patients and calculated the NaR. We also calculated D/P(Na) during the test; plasma and dialysate sodium concentrations were measured by F, D-ISE and I-ISE. RESULTS: NaR was lower (P<0.001) with D-ISE (69+/-29 mmol) than with F (81+/-29 mmol) or I-ISE (79+/-28 mmol). D/P(Na) was also lower at baseline (0.92+/-0.02 vs 0.95+/-0.02 and 0.95+/-0.02; P<0.001), after 60 min (0.87+/-0.03 vs 0.90+/-0.03 and 0.90+/-0.03; P<0.001) and at the end of PET (0.88+/-0.04 vs 0.92+/-0.04 and 0.92+/-0.04; P<0.001) when measured by D-ISE in comparison with F and I-ISE, respectively. CONCLUSIONS: NaR and D/P(Na) were lower when measured by the D-ISE method compared with the F and I-ISE methods. NaR and D/P(Na) were similar when measured by F or I-ISE. I-ISE can be used reliably in the evaluation of NaR and D/P(Na) in everyday clinical practice of peritoneal dialysis. 相似文献
36.
Pathologic changes during acute Q fever: influence of the route of infection and inoculum size in infected guinea pigs. 总被引:3,自引:1,他引:2 下载免费PDF全文
As assessed by both standard histological staining and immunochemistry, intraperitoneal inoculation of C. burnetii in guinea pigs led to pathologic changes mainly in the liver, whereas intranasal inoculation led to pathologic changes mainly in the lungs. Myocarditis and positive blood cultures were observed only in those animals which received the highest inoculum. We therefore conclude that both the route of infection and the size of the inoculum influence clinical expression in acute Q fever. 相似文献
37.
The aim of this study was to determine whether the use of bactericidal coatings or immersion in antibiotic solution reduces or prevents bacterial adhesion onto ureteric stents. Precut segments of full silicone, silver-coated and hydrogel-coated ureteric stents were incubated with two uropathogenic bacterial strains with and without previous immersion in antibiotic solution. Tobramycin, ceftriaxone and ciprofloxacin solutions were used, as these antibiotics are commonly administered for the prophylaxis and treatment of urinary tract infection (UTI). Microbiological analysis showed that immersion of ureteric stents in ceftriaxone and ciprofloxacin yielded a significant reduction of bacterial adhesion, whereas immersion in tobramycin did not. The surface material of the stents had no direct influence on bacterial adhesion. In this experimental study, neither the silver nor the hydrogel coat reduced bacterial adhesion onto ureteric stents whereas immersion in a suitable antibiotic solution significantly reduced and even prevented this phenomenon, probably due to the adhesion of the antibiotic onto the stent surface. Prevention of bacterial adhesion onto ureteric stents is essential to reduce the risk of UTI in connection with these devices. 相似文献
38.
J-H. Longeville P. De La M. Hall P. Dolan A. W. Holt P. E. Lillie J. A. R. Williams R. T. A. Padbury 《HPB surgery》1997,10(3):159-162
We describe a case of giant cavernous haemangioma of the liver with disseminated intravascular coagulopathy (Kasabach-Merritt syndrome) which was cured by orthotopic liver transplant.A 47 year old man presented with bleeding and tender massive hepatomegaly after tooth extraction. Investigations showed disseminated intravascular coagulopathy and a giant hepatic haemangioma involving both lobes of the liver. Initial treatment failed to resolve the coagulopathy and liver resection was attempted. At laparotomy the turnout was unresectable and the only option for cure was to offer a liver transplantation. The orthotopic liver transplant was performed 20 days after initial laparotomy. Subsequently, all coagulation parameters returned to normal and the patient remains well after 12 months. Orthotopic liver transplant can be considered for giant hepatic haemangioma with Kasabach-Merritt syndrome when resection is necessary and a partial hepatectomy is not technically feasible. 相似文献
39.
G. Rosa G. Conti P. Orsi F. D'Alessandro I. La Rosa G. Di Giugno A. Gasparetto 《Acta anaesthesiologica Scandinavica》1992,36(2):128-131
The effects of sedative-hypnotic doses of propofol on respiratory drive and pattern have not yet been extensively described. Repeated small boluses of propofol (0.6-0.3 mg.kg-1) were administered to ten ASA I patients undergoing carpal tunnel release using regional anaesthesia. Airway pressure, capnography and pneumotachography were continuously recorded. With respect to basal values, no significant variations of respiratory rate, minute volume, tidal volume, inspiratory and expiratory time, total expiratory cycle, Ti/Ttot, TV/Ti, P0.1, EtCO2 and blood gas analysis were observed. Low doses of propofol, to maintain conscious sedation of light sleep, have not been shown to cause respiratory depression. 相似文献
40.