全文获取类型
收费全文 | 1899篇 |
免费 | 124篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 41篇 |
妇产科学 | 11篇 |
基础医学 | 352篇 |
口腔科学 | 21篇 |
临床医学 | 177篇 |
内科学 | 405篇 |
皮肤病学 | 32篇 |
神经病学 | 136篇 |
特种医学 | 28篇 |
外科学 | 293篇 |
综合类 | 10篇 |
预防医学 | 79篇 |
眼科学 | 47篇 |
药学 | 175篇 |
肿瘤学 | 207篇 |
出版年
2022年 | 15篇 |
2021年 | 20篇 |
2020年 | 21篇 |
2019年 | 23篇 |
2018年 | 26篇 |
2017年 | 20篇 |
2016年 | 22篇 |
2015年 | 37篇 |
2014年 | 43篇 |
2013年 | 62篇 |
2012年 | 92篇 |
2011年 | 103篇 |
2010年 | 51篇 |
2009年 | 58篇 |
2008年 | 102篇 |
2007年 | 82篇 |
2006年 | 70篇 |
2005年 | 86篇 |
2004年 | 68篇 |
2003年 | 61篇 |
2002年 | 86篇 |
2001年 | 79篇 |
2000年 | 58篇 |
1999年 | 48篇 |
1998年 | 27篇 |
1997年 | 19篇 |
1996年 | 21篇 |
1995年 | 26篇 |
1994年 | 14篇 |
1993年 | 22篇 |
1992年 | 37篇 |
1991年 | 37篇 |
1990年 | 37篇 |
1989年 | 34篇 |
1988年 | 34篇 |
1987年 | 28篇 |
1986年 | 29篇 |
1985年 | 23篇 |
1984年 | 17篇 |
1983年 | 14篇 |
1979年 | 13篇 |
1977年 | 14篇 |
1974年 | 16篇 |
1973年 | 14篇 |
1971年 | 18篇 |
1970年 | 11篇 |
1968年 | 10篇 |
1966年 | 11篇 |
1928年 | 10篇 |
1927年 | 11篇 |
排序方式: 共有2034条查询结果,搜索用时 15 毫秒
1.
In this new radioimmunoassay system for determination of amatoxins in urine and plasma, a novel chemical approach is used for antigen and 125I-tracer production, based on a detoxified alpha-amanitin derivative (aldoamanitin). Total assay time, including data processing, is less than 100 min. The lowest detectable concentration is 1 microgram/L for urine, 0.1 microgram/L for plasma. In the clinically significant range, within-run CVs are less than 8%. This new 125I-based assay is a significant improvement over existing 3H technology in terms of speed, precision, and freedom from interference. 相似文献
2.
Maria P. Panozzo Carlo Fabris Daniela Basso Giuseppe Del Favero Aldo Infantino Attilio Cecchetto Mario Plebani Remo Naccarato 《Clinical and experimental pharmacology & physiology》1993,20(3):185-191
1. The authors investigated the effect of two extrahepatic cholestasis models (one by bile duct ligation and the other by choledocho-jugular fistula) on the hepatic clearance of horseradish peroxidase in male Sprague-Dawley rats divided into four groups. 2. In groups A (n = 5 rats) and B (n = 5), bile duct ligation was performed, while a choledocho-jugular fistula was created in groups C (n = 5) and D (n= 7). A 10 mg intravenous bolus of horseradish peroxidase was injected after 24 h (groups A and C), 48 h (groups B and D) or 1 h (Group E; five sham-operated rats). Serum and bile samples were then serially collected for 2 h. 3. In all groups, serum horseradish peroxidase levels increased soon after injection and then rapidly decreased, the curves being similar. Biliary excretion increased for 30 min and then slowly decreased. The highest horseradish peroxidase biliary concentrations and outputs were found in Group B followed by Group A; both groups had significantly higher levels than Group E. No difference was found between horseradish peroxidase biliary excretion of groups C and D and that of sham-operated rats. 4. When each group was considered separately, sampling times correlated with the corresponding ratios of bile/ plasma HRP. Significant differences were found between the relative slopes of groups A, B and E, but not between those of groups C, D and E. 5. In conclusion, bile duct obstruction greatly affects the plasma-bile transfer of fluid phase markers, such as horseradish peroxidase, while single retention, caused by choledocho-jugular fistula, has no influence. The increased biliary hyperpressure related to the duration of cholestasis may account for the degree of horseradish peroxidase transfer which, in turn, probably depends on an enhanced paracellular passage. 相似文献
3.
Andreas Frei und René Raggenbas 《Sozial- und Pr?ventivmedizin》1989,34(6):279-280
4.
J Goldhahn M Reinhold M Stauber C Knop R Frei E Schneider B Linke 《Journal of orthopaedic research》2006,24(5):917-925
The goal of our study was to evaluate two newly developed implant designs and their behavior in terms of subsidence in lumbar vertebral bodies under cyclic loading. The new implants were evaluated in two different configurations (two small prototypes vs. one large prototype with similar load-bearing area) in comparison to a conventional screw-based implant (MACS TL). A pool of 13 spines with a total of 65 vertebrae was used to establish five testing groups of similar bone mineral density (BMD) distribution with eight lumbar vertebrae each. In additional to BMD assessment via dual-energy X-ray absorptiometry, cancellous BMD and structural parameters were determined using a new generation in vivo 3D-pQCT. The specimens were loaded sinusoidally in force control at 1 Hz for 1000 cycles at three load levels (100, 200, and 400 N). A survival analysis using the number of cycles until failure (Cox regression with covariates) was applied to reveal differences between implant groups. All new prototype configurations except the large cylinder survived significantly longer than the control group. The number of cycles until failure was significantly correlated with the structural parameter Tb.Sp. and similarly with the cancellous BMD for three of five implants. In both large prototypes the cycle number until failure significantly correlated with the preoperative distance to the upper endplates. Although the direct relationship between bone structure or density and mechanical breakage behavior cannot be conclusively proven, all the prototypes adapted for poor bone structure performed better than the comparable conventional implant. 相似文献
5.
D P Griswold M W Trader E Frei W P Peters M K Wolpert W R Laster 《Cancer research》1987,47(9):2323-2327
Alkylating agent-sensitive and -resistant L1210 leukemia cell lines were used to determine the tumor response to dose levels of drugs that exceeded conventional doses up to a factor of 10. Since those dose levels were lethal to the host mice, tumor response was based on the results of in vivo bioassays of spleen and/or tumor from drug-treated and control mice. When mice bearing about 10(8) drug-sensitive leukemic cells were treated with a single, conventional (approximately 10% lethal) dose of cis-diamminedichloroplatinum, L-phenylalanine mustard (melphalan), or 1,3-bis(2-chloroethyl)-1-nitrosourea, 10(1) to 10(4) tumor cells were recovered by bioassay. Treatment at doses that were 2 to 8 times the 10% lethal dose of either of those drugs resulted in no recoverable cells and survival of all bioassay recipient mice. Mice bearing advanced L1210 leukemia resistant to cis-diamminedichloroplatinum (L1210/DDPt), 1,3-bis-(2-chloroethyl)-1-nitrosourea (L1210/BCNU), cyclophosphamide (L1210/CPA), or melphalan(L1210/L-PAM) also were treated with a 10% lethal dose and greater doses of the drug to which the tumor line was resistant. Bioassay results indicated a direct correlation between dose intensity and tumor cell kill, the response being linear. Similarly, when mice with L1210/BCNU were treated with high doses of N-(2-chloroethyl)-N'-(2,6-dioxo-3-piperidinyl)-N-nitrosourea or 1,1',1'-phosphinothioylidynetrisaziridine (thioTEPA) and when mice with L1210/DDPt were treated with cyclophosphamide, an increasing, linear cell kill resulted throughout the high-dose range. Overall, these results indicate that resistance to these alkylating agents can be overcome by dose intensification and that the tumor response is linear in relation to increasing dose level. 相似文献
6.
BACKGROUND. Cisplatin and 5-fluorouracil have noted synergy in preclinical systems. The authors combined methotrexate with infusional cisplatin and 5-fluorouracil in an attempt to produce a regimen with improved activity in advanced NSCLC. METHODS. Twenty-six ambulatory patients with previously untreated non-small cell lung cancer were treated with continuous-infusion cisplatin (25 mg/m2/day for 5 days), 5-fluorouracil (800 mg/m2/day for 5 days), and intermediate-dose methotrexate (200 mg/m2 on days 15, 22), followed by leucovorin rescue (PFM regimen). RESULTS. Patients received a median of four cycles of therapy. Two patients had a complete response, and 10 had a partial response (overall response rate, 46.2% or 12 of 26). The median time to treatment failure was 22.5 weeks; the median survival was 55 weeks from the start of chemotherapy. There were no toxic deaths attributed to chemotherapy. Thrombocytopenia was the only Grade 4 toxicity (27%). Grade 1/4 and 2/4 peripheral neuropathy occurred in 17 of 26 patients (66%) and was associated with a cumulative cisplatin dose of more than 300 mg/m2. CONCLUSIONS. PFM (using continuous-infusion cisplatin) produced a high response rate but resulted in an high incidence of low-grade peripheral neuropathy. 相似文献
7.
8.
The in vivo functional characteristics of continuous arteriovenous hemofiltration (CAVH) were studied in 21 intensive-care patients with acute renal failure. FH-66 hemofilters were applied. The relationships between prefilter blood pressure (BP), blood flow (QB) and filtration rate (QF) were evaluated by stepwise clamping of the arterial access and simultaneous measurements of these parameters. The correlations between BP and QB, and between QB and QF, were linear (p less than 0.001). The total pressure drop across the extracorporeal circuit was 90 +/- 12 mmHg with Scribner shunt and 70 +/- 13 mmHg with femoral catheters as vascular access. The relative pressure drops across arterial access, hemofilter and venous access for Scribner shunt and for femoral catheter were 30%, 43% and 27% and 12%, 74% and 14%, respectively. At a given BP, QB was lower and transmembrane filtration pressure (TMP) higher in CAVH with Scribner shunt. QB was 102 +/- 38 ml/min; QF was 20 +/- 7 ml/min. The effects of hemofilter geometry and membrane material on functional parameters of CAVH were evaluated by applying four hemofilters (Amicon D-20 HP, D-30 HP, Gambro FH-66, Fresenius AV-400) consecutively in the same patient. The filters were different with respect to hollow fiber length, its internal diameter, number of fibers and membrane material. BP, hematocrit (Hct) and plasma protein remained constant during measurements. QB increased with decreasing filter resistance. QF did not increase with increasing QB. QF was also not closely related to membrane surface area. The hydraulic permeability (Lp) had a major impact on QF.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
9.
10.
U. Settmacher M. Heise K. Dette U. Frei P. Neuhaus 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》1997,382(3):138-140
Primary malignant tumors of the aorta are only rarely reported. We describe here our findings in a 55-year-old patient who was referred to us with progressive renal insufficiency. At angiography, right renal artery occlusion and high-grade stenosis of the left renal artery was found in this patient, who had undergone aortobiliacal reconstruction for acute Leriche syndrome 5 months previously. Histological evaluation of thrombotic material revealed an intraluminal malignant tumor to be the underlying cause. This diagnosis was then confirmed in samples harvested during angiography. CT scan showed an extension beginning 2 cm proximal to the celiac trunk. The patient was treated by thoracoabdominal resection of the aorta, including the paraaortal tissue, left side nephrectomy, and adrenalectomy. A thoracoabdominal aortic prosthesis was inserted up to the iliacal bifurcations and the celiac and superior mesenteric arteries reimplanted. Right nephrectomy followed 3 weeks later. The postoperative course was uneventful. 相似文献