全文获取类型
收费全文 | 368383篇 |
免费 | 41399篇 |
国内免费 | 13977篇 |
学科分类
医药卫生 | 423759篇 |
出版年
2024年 | 1003篇 |
2023年 | 6562篇 |
2022年 | 12425篇 |
2021年 | 16551篇 |
2020年 | 15214篇 |
2019年 | 13987篇 |
2018年 | 13941篇 |
2017年 | 14556篇 |
2016年 | 15427篇 |
2015年 | 17827篇 |
2014年 | 26061篇 |
2013年 | 26764篇 |
2012年 | 22400篇 |
2011年 | 23838篇 |
2010年 | 18363篇 |
2009年 | 18392篇 |
2008年 | 19219篇 |
2007年 | 18625篇 |
2006年 | 16755篇 |
2005年 | 14619篇 |
2004年 | 12539篇 |
2003年 | 10707篇 |
2002年 | 8829篇 |
2001年 | 7839篇 |
2000年 | 6571篇 |
1999年 | 5770篇 |
1998年 | 5168篇 |
1997年 | 4644篇 |
1996年 | 3964篇 |
1995年 | 3647篇 |
1994年 | 3051篇 |
1993年 | 2481篇 |
1992年 | 2082篇 |
1991年 | 1919篇 |
1990年 | 1474篇 |
1989年 | 1347篇 |
1988年 | 1227篇 |
1987年 | 1009篇 |
1986年 | 875篇 |
1985年 | 1162篇 |
1984年 | 1022篇 |
1983年 | 699篇 |
1982年 | 729篇 |
1981年 | 615篇 |
1980年 | 531篇 |
1979年 | 375篇 |
1978年 | 278篇 |
1977年 | 214篇 |
1976年 | 165篇 |
1975年 | 86篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Short-term outcome analysis of a randomized study comparing laparoscopic vs open colectomy for colon cancer 总被引:19,自引:6,他引:13
A. M. Lacy J. C. García-Valdecasas J. M. Piqué S. Delgado E. Campo J. M. Bordas P. Taurá L. Grande J. Fuster J. L. Pacheco J. Visa 《Surgical endoscopy》1995,9(10):1101-1105
The authors examined the impact of the laparoscopic approach on the early outcome of resected colon carcinomas. The role of laparoscopic techniques in the treatment of colon carcinomas is questionable. Previous studies have suggested technical feasibility of surgical resections of these cancers by laparoscopic means and have implied a benefit to laparoscopic technique for patients undergoing colorectal resections. A prospective, randomized study was conducted comparing laparoscopic assisted colectomy (LAC) open colectomy (OC) for colon cancer. We present the preliminary results in relation to the short-term outcome and judge the feasibility of the laparoscopic procedure to as a way of performing accurate oncologic resection and staging. Benefit has been demonstrated with LAC in this setting. Passing flatus, oral intake, and discharge from hospital occurred earlier in LAC- than OC-treated patients The mean operative time was significantly longer in the LAC group than in the OC group. The overall morbidity was significantly lower in the LAC group. No significant differences were observed between both groups in the number of lymph nodes removed or the pathological stage following the Astler-Coller modification of the Dukes classification. The laparoscopic approach improves the short-term outcome of segmental colectomies for colon cancer. However, the further follow-up of these patients will allow us to answer in the near future whether or not the LAC may influence the long-term outcome.Presented at the annual meeting of the Society of American Gastrointestinal Surgeons (SAGES), Orlando, FL, USA, 11–14 March 1995 相似文献
992.
M. Brugiatelli B. Jaksic A. Planinc-Peraica R. Kusec S. Ostojic V. Callea P. Lacopino F. Morabito C. Stelitano D. Lutz 《European journal of haematology》1995,55(3):158-163
Abstract: In 1982 the IGCI CLL cooperative group decided to investigate the usefulness of treating, at diagnosis B-cell chronic lymphocytic leukemia (CLL) in early and stable phase of the disease. From January 1982 to December 1986, 148 patients were randomized either to receive immediate treatment with chlorambucil (CLB) or to defer therapy to the time of progression. The early and stable phase of the disease was defined by a total tumor mass (TTM) score < 9, the absence of anemia or thrombocytopenia and a doubling time > 12 months. The main end-point of the study was survival. At the last evaluation in April 1993, after a median follow-up of 75 months, no significant difference was found in overall survival between early vs. deferred treatment patients from every cause of death as well as from death due to CLL-related causes only. The same results were obtained when the patients in more favorable stages, such as Binet stage A and TTM < 4.5, were considered. Interestingly, the incidence of epithelial cancer was similar in the two groups. Early treatment was associated with a significantly better response and a lower progression rate. From this long-term experience, it can be concluded that immediate chemotherapy with CLB is not beneficial for CLL patients in early and stable phase of the disease in terms of survival. 相似文献
993.
994.
The performance of the CELL-DYN 1700® (Abbott Diagnostics, Abbott Park, IL, USA) was evaluated in a tertiary care hospital laboratory using the guidelines proposed by the German Society of Clinical Chemistry. Precision, accuracy, linearity, background counts, and carry-over were satisfactory for all measured standard parameters including haemoglobin concentration, haematocrit, red blood cell count, mean corpuscular volume (MCV), red cell distribution width (RDW), white blood cell count and platelet count. With 259 selected normal and abnormal blood samples the results of the CELL-DYN 1700® (CD1700) compared very well (r > 0.96 for all parameters with exception of RDW) with those obtained with the Bayer Diagnostic H-1 and the Hoffmann-La Roche Cobas Argos systems. This study considered in particular the performance of the CD1700 three-part leucocyte differential. For those samples without instrument-generated suspect flags, the neutrophil and lymphocyte percentages were highly correlated with the results of the H-1 blood cell counter (r = 0.97 and 0.98, respectively) and with manual 400-cell differentials (r = 0.91 and 0.88, respectively). In contrast, the CD1700 mid-fraction which comprised the composite total of mono cytes, eosinophils, basophils and precursor white cells (when present) could not be directly compared to the differentials from the H-1 system or from manual microscopy. For those samples with CD1700 instrument suspect flags, the neutrophil and lymphocyte differential results also compared well with both the H-1 (r = 0.93 and 0.93, respectively) and manual estimates (r = 0.89 and 0.87, respectively). In conclusion, the CD1700 is an accurate haematology analyser for cellular blood counts and three-part leucocyte differentiation. 相似文献
995.
Neuropathology in non-human immunodeficiency virus-infected drug addicts: hypoxic brain damage after chronic intravenous drug abuse 总被引:3,自引:0,他引:3
Neuropathological studies were carried out on 180 human immunodeficiency virus-seronegative intravenous drug addicts. The
findings in victims of acute heroin intoxication (n = 116) were congestion (99.1%), capillary engorgement (68.1%), and/or perivascular bleeding (68.1%) – hemodynamic processes
attributable to toxic primary respiratory failure. In a high percentage of these cases (88%), cerebral edema was also present.
In 18 cases of acute heroin intoxication who survived for periods of hours or days, the sole postmortem finding was ischemic
nerve cell damage, resembling that typically seen in systemic hypoxia. Semiquantitative analysis revealed nerve cell loss
in the hippocampal formation and/ or Purkinje cell layer in 26% of the 162 chronic drug abusers. By contrast, in nearly 80%
of these cases, the hippocampus showed enhanced expression of glial fibrillary acid protein by astrocytes and/or a proliferation
of microglia, demonstrated by CD68 expression. Since such reactive processes are produced by primary neuronal damage, it can
be assumed that chronic intravenous drug abuse results in obviously ischemic nerve cell loss. This could be demonstrated in
the hippocampus, but it must also occur throughout the whole brain. The demonstration of ischemic nerve cell damage and neuronal
loss or secondary reactive alterations has not been described previously.
Received: 31 March 1995 / Revised, accepted: 27 November 1995 相似文献
996.
肾病患儿免疫细胞对肾小球上皮细胞合成基质的影响 总被引:1,自引:0,他引:1
目的为了明确免疫细胞对肾小球上皮细胞(glomerularepithelialcelGEC)合成功能的直接作用。方法应用肾小球细胞体外培养,同位素掺入及放射免疫技术,以总胶原,层粘连蛋白,Ⅲ型前胶原及Ⅳ型胶原的合成为观察指标,动态研究了不同病理类型原发性肾病综合征(INS)患儿外周血单个核细胞(peripheralbloodmononuclearcelPBMC)对GEC生物功能的影响。结果(1)肾病极期未经激素治疗组(未治组)PBMC上清明显促进了GEC合成层粘连蛋白;(2)未治PBMC上清抑制了GEC合成总胶原;(3)未治组PBMC上清促进了Ⅲ型前胶原的合成,而对Ⅳ型胶原的合成无明显影响;(4)肾病患儿PBMC的上述作用与是否足量激素治疗有关,而与尿蛋白能否阴转、肾组织病理类型、肾病临床类型等无直线相关关系。结论原发性肾病患儿循环免疫细胞可影响GEC合成细胞外基质的功能。免疫细胞的这种活性可被激素治疗改变。 相似文献
997.
T. Ishikawa T. Yagi H. Sadamori N. Ishine H. Sasaki M. Oishi N. Tanaka 《Transplant international》1998,11(S1):S410-S416
Abstract This study was designed to investigate the effects of differences in the route of nutritional support of the donor on cold ischemia/reperfusion injury. Participation of Kupffer cells in these effects, based on the analysis of hepatic energy metabolism in early phases of reperfusion was also investigated. Orthotopic liver transplantation was performed between Large-White pigs weighing 20–30 kg after a 4-h cold preservation of the graft in Euro-Collins solution at 4°C. One group was fed orally with a standard laboratory diet (FED group, n = 5), a second group was fasted and given 20% glucose intravenously (12 kJ/kg per day) (PEF group, n = 5), and a third group was fed orally with a standard laboratory diet and given GdCI3 (10 mg/kg) intravenously 24 h before operation (FEDGD group, n = 5). These treatments were given for 7 days prior to harvesting. The survival time was significantly longer in the PEF (34.8 ± 5.5 days) and FEDGD (28.0 ± 11.9 days) groups than in the FED (9.8 ± 2.0 days) group ( P < 0.05). The serum hyaluronic acid elimination rate determined from 1 to 2 h after reperfusion was significantly lower in the FED group than in the other two groups ( P < 0.001). The glycogen content of the livers 1 h after reperfusion in all three groups had been consumed rapidly, but the ATP content of the livers was significantly reduced in the FED group alone ( P < 0.01). Hepatic FFA clearance (CFFA ) was moderately increased in all three groups in the early phase after reperfusion, but it was higher in the FED group than in the other two groups, with significant differences 1 and 2 h after reperfusion ( P < 0.05). In conclusion, parenteral nutrition of the donors reduced cold ischemia/reperfusion injury which is related to Kupffer cell activation and, thus, was better than enteral nutrition for donor management. 相似文献
998.
999.
1000.
组织工程化肌腱研究进展 总被引:17,自引:2,他引:15
对组织工程化肌腱领域中目前研究的主要成果进行综述,着重阐述了肌腱细胞外基质替代物、肌腱细胞生物学性质及肌腱细胞与细胞外基质材料复合研究中的主要问题。认为,研制适于肌腱细胞生长、粘附和发挥功能的细胞外基质材料;建立生长、增殖可调控的肌腱细胞系;在模拟体内力学条件下,进行肌腱细胞三维培养,将是研究具有特定修复功能的组织工程化肌腱的重要问题。 相似文献