全文获取类型
收费全文 | 41714篇 |
免费 | 2922篇 |
国内免费 | 2756篇 |
专业分类
耳鼻咽喉 | 103篇 |
儿科学 | 563篇 |
妇产科学 | 203篇 |
基础医学 | 2691篇 |
口腔科学 | 86篇 |
临床医学 | 4627篇 |
内科学 | 11092篇 |
皮肤病学 | 187篇 |
神经病学 | 320篇 |
特种医学 | 3066篇 |
外国民族医学 | 3篇 |
外科学 | 8904篇 |
综合类 | 4810篇 |
预防医学 | 1549篇 |
眼科学 | 38篇 |
药学 | 2979篇 |
13篇 | |
中国医学 | 1217篇 |
肿瘤学 | 4941篇 |
出版年
2024年 | 74篇 |
2023年 | 622篇 |
2022年 | 1329篇 |
2021年 | 1595篇 |
2020年 | 1415篇 |
2019年 | 1203篇 |
2018年 | 1248篇 |
2017年 | 1083篇 |
2016年 | 1400篇 |
2015年 | 1539篇 |
2014年 | 2821篇 |
2013年 | 2533篇 |
2012年 | 2555篇 |
2011年 | 2622篇 |
2010年 | 2383篇 |
2009年 | 2496篇 |
2008年 | 2550篇 |
2007年 | 2509篇 |
2006年 | 2377篇 |
2005年 | 1946篇 |
2004年 | 1395篇 |
2003年 | 1220篇 |
2002年 | 1109篇 |
2001年 | 992篇 |
2000年 | 835篇 |
1999年 | 683篇 |
1998年 | 633篇 |
1997年 | 553篇 |
1996年 | 448篇 |
1995年 | 439篇 |
1994年 | 427篇 |
1993年 | 305篇 |
1992年 | 279篇 |
1991年 | 208篇 |
1990年 | 172篇 |
1989年 | 180篇 |
1988年 | 167篇 |
1987年 | 106篇 |
1986年 | 113篇 |
1985年 | 114篇 |
1984年 | 88篇 |
1983年 | 53篇 |
1982年 | 81篇 |
1981年 | 87篇 |
1980年 | 68篇 |
1979年 | 56篇 |
1978年 | 58篇 |
1977年 | 43篇 |
1976年 | 41篇 |
1974年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Jean de Ville de Goyet Raymond Reding Viktoria Hausleithner Jan Lerut Jean-Bernard Otte 《Transplant international》1995,8(4):280-285
This paper describes a quick procedure for cadaveric liver graft retrieval during multiple organ harvesting. The technique is based on minimal preliminary dissection, absence of in situ direct portal perfusion, and en bloc removal of the liver and pancreas, with an aortic patch encompassing the coeliac trunk and superior mesenteric artery. The results of 110 pediatric liver transplantations with 109 organs harvested using this technique are reported. There were no graft harvesting injuries. The liver graft primary nonfunction rate was 4.5% (5/110). The 3-month retransplantation rate was 10%. The actual patient survival rates were 93% at 3 months and 90% at 1 year; actual graft survival rates were 85.5% and 78%, respectively. The technique described was at least as safe as conventional procedures. A major advantage of the procedure is its flexibility, which allows for the easily combined procurement of other organs (whole pancreas and intestine). 相似文献
12.
13.
Hexachlorobenzene (HCB) is still frequently found at elevated levels in human adipose tissue and breast milk. As intoxication
with HCB causes neurological disturbance in human beings, the purpose of the present study was to examine neurobehavioral
functions in rats after pre- and postnatal exposure. Female rats were fed diets with 0, 4, 8, or 16 mg HCB/kg diet. Exposure
started 90 days prior to mating and was continued throughout mating, gestation, and lactation. Thereafter, the offspring were
given the same diets as their respective mothers. HCB levels were determined in the brain, the liver, and in the adipose tissue
from virgin rats, dams, and the offspring. Concentrations on a lipid basis were found to decline in the order adipose>liver>brain.
The exposure levels chosen did not cause gross toxic effects in dams or offspring. There were dose-related increases in liver-to-body-weight
ratios in exposed dams, but not in unmated females treated alike. Behavioral testing was conducted in the offspring. Examination
of open-field activity on PND 21, and of active avoidance learning on PND 90 failed to reveal significant differences between
groups. Training of operant behavior started at the age of 150 days in the offspring from the control, the 8-mg group, and
the 16-mg group. Animals were trained on a fixed interval schedule of 1 min (FI-1). On this schedule, responses were reinforced
by a food pellet every time 1 min had elapsed after the preceding reinforcement. There were dose-dependent reductions in the
post-reinforcement pause, e.g. the time between each reinforcement and the first reaction emitted after it. In addition, the
index of curvature, which describes the efficiency of performance on the FI-1 schedule, was decreased in a dose-dependent
fashion.
Received: 12 April 1994 / Accepted: 26 June 1995 相似文献
14.
Dr. J. Tajti MD PhD ; Dr. K. Sas MD ; Dr. D. Szok MD ; Dr. E. Vörös MD ; Dr. L. Vécsei MD DSc 《Headache》1996,36(4):259-260
We report on a patient with clusterlike headache and multiple brain metastases of lung cancer. Initially, cluster headache was suggested clinically by characteristic symptoms without any focal central nervous system signs. However, magnetic resonance imaging demonstrated multiple brain metastases. It is possible that tumor necrosis factor may have played a role in initiating the clusterlike headache. 相似文献
15.
José Ignacio Bilbao Mercedes Arias Jesús María Longo Pedro Luis Alejandre María Teresa Betés Arlette María Elizalde 《Cardiovascular and interventional radiology》1997,20(2):149-153
Percutaneous embolization of large portosystemic collaterals was performed in three patients following placement of a transjugular
intrahepatic portosystemic shunt in order to improve hepatopetal portal flow. Improved hepatic portal perfusion was achieved
in these cases, thereby theoretically reducing the risk of chronic hepatic encephalopathy. 相似文献
16.
James R. Trudell Wei-Qi Lin Dale A. Chrystof Gary Kirshenbaum C. Murray Ardies 《Alcoholism, clinical and experimental research》1995,19(3):753-758
Ethanol-induced fatty liver in rats was attenuated by repeated running exercise, and the protective effect of exercise was associated with the synergistic expression of heat shock proteins (HSP72). Rats were placed in four groups of six. The two ethanol-fed groups of rats received a liquid diet (Lieber-DeCarli formulation) in which 36% of the calories were derived from ethanol. One group remained sedentary (S/E), whereas the other was trained to run on a rodent treadmill at a speed of 27 m/min, 1 hr/day, 5 days/week, for 7 weeks (R/E). Two other groups–one exercised as previously mentioned (R/C) and one sedentary (S/C)–received control-liquid diets in which the ethanol was isocalorically substituted with a dextran/maltose mixture. The degree of fatty infiltration in liver sections stained with hematoxylin and eosin was graded on a 0–4 scale and the data analyzed by ANOVA on ranks. Ethanol significantly induced fatty infiltration in the S/E group, whereas fatty infiltration in the livers of the R/E group was not different from the S/C group. Electrophoresis and Western blotting of liver homogenates demonstrated that HSP72 was not expressed in either the S/C or S/E groups and was only slightly expressed in the R/C group. The combination of exercise and ethanol, however, resulted in an elevated expression of HSP72 in the R/E group. The content of HSP73 was unaffected by any treatment. 相似文献
17.
A rat model of monitoring liver allograft rejection 总被引:5,自引:0,他引:5
Timi Martelius Heikki Mäkisalo Krister Höckerstedt Eero Taskinen Irmeli Lautenschlager 《Transplant international》1997,10(2):103-108
Rat models are often used to study liver allograft rejection. We have established a model for rat liver allograft rejection,
monitored by fine needle aspiration biopsy (FNAB), in the strain combination PVG-to-BN with a mean survival time of 37 ± 20
days. In this model, we observed acute rejection with an intense peak of lymphoid blasts and lymphocyte-dominated inflammation
in the FNAB [9.1 ± 3.0 corrected increment units (CIU)], and an eventual increase in macrophages (up to 4.2 ± 4.4 CIU), together
with fibrosis and parenchymal necrosis in the graft. Markers of immune activation, such as an increase in IL-2-receptor (from
1 % ± 2 % to 21 % ± 13 %) and class II (from 20 % ± 9 % to 43 % ± 13 %) expressing lymphoid cells and induction of ICAM-1
in the graft, were consistent with the overall cellular response. The FNAB correlated well with parallel graft histology.
In this rat model, the atraumatic monitoring makes a close follow-up possible without having to sacrifice the experimental
animals. This saves work, animals, and costs in the study of liver rejection.
Received: 2 July 1996 Accepted: 28 October 1996 相似文献
18.
T. Scholz Ø. Mathisen A. Bergan S. Osnes R. Innes T. Pedersen A. O. Aasen O. Søreide 《Transplant international》1997,10(3):180-184
We have introduced and evaluated several modifications of the conventional venovenous bypass (VVBP) in 29 adult patients
undergoing liver transplantation (OLT). A percutaneous technique for insertion of a jugular venous return cannula and a femoral
vein cannula was applied. The inferior mesenteric vein (IMV) was used for splanchnic decompression, which facilitated dissection
of the recipient liver and allowed portal anastomosis to be performed without disconnecting the portal bypass. A heat exchanger
was introduced into the bypass circuit to prevent heat loss. The percutaneous technique prevented complications related to
dissection in the axilla and groin. Hemodynamic characteristics corresponded to those found using the traditional technique.
Complications related to the VVBP were seen in only one patient in whom the femoral catheter was accidentally introduced into
the femoral artery. We conclude that percutaneous cannulas, use of the IMV for splanchnic decompression and the introduction
of a heat exchanger offer significant benefits and that they are safe and reliable.
Received: 23 August 1996 Received after revision: 14 January 1997 Accepted: 27 January 1997 相似文献
19.
Abstract One hundred eighty-one consecutive patients with fulminant hepatic failure (FHF) presenting in a 2-year period were reviewed. In this cohort we examined the impact of pretransplant renal failure on mortality and morbidity following orthotopic liver transplantation (OLTx). Twenty-seven patients (18 female, 9 male) with a median age of 43.5 years (range 19–65 years) underwent OLTx. FHF was due to idiosyncratic drug reaction ( n = 4), paracetamol overdose ( n = 3), seronegative hepatitis ( n = 17), hepatitis B ( n = 1), veno-occlusive disease ( n = 1), and Wilson's disease ( n = 1). Renal failure was present in 14 patients, 7 of whom died (whereas there was 100 % survival in patients without renal failure). Pretransplant renal failure was associated with prolonged mechanical ventilation (13 days vs 6 days, P = 0.05), prolonged intensive care stay (17 days vs 8 days, P - 0.01) and prolonged hospital stay (27 vs 21 days, P = NS). Pretransplant renal failure did not predict renal dysfunction at 1 year after OLTx. We conclude that the survival of patients transplanted for FHF is inferior to that of patients transplanted for chronic liver disease (67 % vs 88 % 1-year survival in Birmingham). For patients with FHF undergoing transplantation, pretransplant renal failure strongly predicts poor outcome with significantly greater consumption of resources. 相似文献
20.
D. Tolosa I. Azorín J. Renau-Piqueras M. Sancho-Tello C. Guerri 《Virchows Archiv : an international journal of pathology》1995,427(3):309-315
Alcohol consumption during pregnancy is teratogenic and induces severe alterations in hepatocytes. In the hepatocyte peroxisomal system, ethanol is converted in the presence of H2O2 to acetaldehyde and water. Therefore, peroxisomal catalase also acts as an antioxidant defence mechanism by removing H2O2 and preventing the formation of hydroxyl radicals in the cell. Alterations in peroxisomal catalase after pre- and pre+postnatal alcohol exposure were investigated in the rat. The effect of pre- and postnatal exposure to ethanol on hepatocyte subpopulations was analysed in isolated hepatocytes originating from periportal, intermediate and perivenous zones. Analysis of catalase revealed that the total activity and content of this enzyme were higher in 12-day-old cells than in cells from newborns and that this increment was more pronounced in treated cells. In controls, the amount of peroxisomal catalase increased mainly in periportal cells, whereas alcohol exposure induced a significant increase in the catalase of perivenous hepatocytes. We conclude that pre- and postnatal alcohol exposure mainly affects the perivenous hepatocyte peroxisomes and that the increase in peroxisomal catalase could constitute a defence mechanism against free radical generation induced by alcohol exposure during the perinatal period. 相似文献