全文获取类型
收费全文 | 1005篇 |
免费 | 78篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 60篇 |
妇产科学 | 8篇 |
基础医学 | 108篇 |
口腔科学 | 29篇 |
临床医学 | 171篇 |
内科学 | 205篇 |
皮肤病学 | 13篇 |
神经病学 | 54篇 |
特种医学 | 244篇 |
外科学 | 64篇 |
综合类 | 22篇 |
预防医学 | 36篇 |
眼科学 | 8篇 |
药学 | 33篇 |
中国医学 | 5篇 |
肿瘤学 | 27篇 |
出版年
2024年 | 3篇 |
2023年 | 8篇 |
2022年 | 2篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 24篇 |
2017年 | 11篇 |
2016年 | 20篇 |
2015年 | 22篇 |
2014年 | 27篇 |
2013年 | 27篇 |
2012年 | 17篇 |
2011年 | 24篇 |
2010年 | 36篇 |
2009年 | 55篇 |
2008年 | 32篇 |
2007年 | 17篇 |
2006年 | 22篇 |
2005年 | 11篇 |
2004年 | 19篇 |
2003年 | 22篇 |
2002年 | 16篇 |
2001年 | 14篇 |
2000年 | 12篇 |
1999年 | 14篇 |
1998年 | 50篇 |
1997年 | 52篇 |
1996年 | 65篇 |
1995年 | 49篇 |
1994年 | 43篇 |
1993年 | 47篇 |
1992年 | 14篇 |
1991年 | 7篇 |
1990年 | 14篇 |
1989年 | 34篇 |
1988年 | 30篇 |
1987年 | 32篇 |
1986年 | 33篇 |
1985年 | 23篇 |
1984年 | 15篇 |
1983年 | 9篇 |
1982年 | 22篇 |
1981年 | 14篇 |
1980年 | 8篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 12篇 |
1976年 | 12篇 |
1975年 | 17篇 |
排序方式: 共有1090条查询结果,搜索用时 0 毫秒
121.
P Debre C Waltenbaugh ME Dorf B Benacerraf 《The Journal of experimental medicine》1976,144(1):277-281
Previous reports from our laboratory have demonstrated the stimulation of specific suppressor T cells in genetic nonresponder mice after immunization with the terpolymer of L- glutamic acid, L-alanine, and L-tyrosine (GAT) (1,2) and with the copolymer of L-glutamic acid and L-tyrosine (GT) (3-5). These findings raise two important questions: (a) do the specific suppressor T cells inhibit an antibody response which would otherwise develop in nonresponder mice; and, (b) can specific helper T cells inhibit an antibody response which would otherwise develop in nonresponder mice; and, (b) can specific helper T-cell activity be detected in these animals. Responsiveness appears to be completely dominant over suppression in (responder x suppressor)F(1) hybrids, therefore, we have been unable to detect suppressor cells in these hybrids after conventional immunization with GAT (2). However , using special conditions of antigen administration, GAT helper activity could be demonstrated in nonresponder DBA/1 (“suppressor”) mice. Thus, GAT-specific helper activity was not detected in these nonresponder animals after immunization with GAT irrespective of the adjuvant used, but could be stimulated by macrophage-bound GAT or by GAT complexed with methylated bovine serum albumin GAT-MBSA (6). In the current report we have taken advantage of the fact that suppressor T-cell activity is more sensitive to cyclophosphamide treatment than T-cell helper activity (7) to demonstrate the presence of GT-specific helper activity in “nonresponder” BALB/c mice. We describe: (a) the dose of cyclophosphamide and conditions of treatment which inhibits the well-documented stimulation of specific suppressor T cells in BALB/c mice injected with GT previous to immunization with GT-MBSA, and (b) the ability of cyclophosphamide to permit the development of primary PFC responses to GT in these “nonresponder” mice. These cyclophosphamide-induced responses are not characterized by the high levels of antibody detected in genetic responder animals. 相似文献
122.
Richter's syndrome with different immunoglobulin light chains and different heavy chain gene rearrangements 总被引:2,自引:0,他引:2
van Dongen JJ; Hooijkaas H; Michiels JJ; Grosveld G; de Klein A; van der Kwast TH; Prins ME; Abels J; Hagemeijer A 《Blood》1984,64(2):571-575
In a patient with Richter's syndrome, the chronic lymphocytic leukemia (CLL) expressed lambda, mu, and delta immunoglobulin (lg) chains and the non-Hodgkin lymphoma (NHL) kappa, mu, and delta lg chains. The difference in lg light chain expression suggests that the CLL and NHL are independent malignancies, or that the oncogenic event occurred in a B cell differentiation stage after the heavy chain gene rearrangements but before the selection of the light chain. Analysis of DNA by Southern blotting revealed that the lg heavy chain genes of the two malignancies were rearranged in a different way. We therefore conclude that in this patient the NHL cannot be regarded as a progression of the CLL but should most likely be considered as an independent B cell malignancy, which arose in a susceptible host. 相似文献
123.
Pharmacokinetics of midazolam in Vietnamese subjects 总被引:2,自引:0,他引:2
KR BALSON DJ MORGAN BH RICHMOND ME McALINDON SL ELLIOTT ND YEOMANS 《Journal of gastroenterology and hepatology》1996,11(10):1177-1180
124.
目的评价具有促进TNF-αmRNA降解的免疫调节剂沙利度胺在预防ERCP术后胰腺炎中的作用。方法建立ERCP术后胰腺炎模型,治疗组术前8天起沙利度胺灌胃,并设立假手术组、无治疗组和赋形物对照组。24h后比较血清淀粉酶水平、胰腺水肿程度以及组织学炎症评分,并比较胰腺组织TNF-αmRNA表达情况。结果沙利度胺显著降低血清淀粉酶、减轻胰腺水肿及组织学炎症评分,并显著降低胰腺组织中TNF-αmRNA的表达。结论TNF-α可能在ERCP术后胰腺炎的发生发展中起着重要作用.预防性使用沙利度胺能有效减轻ERCP术后胰腺炎的严重程度。 相似文献
125.
The presence of clonogenic cells in high-grade malignant lymphoma: a prognostic factor 总被引:7,自引:1,他引:7
Tweeddale ME; Lim B; Jamal N; Robinson J; Zalcberg J; Lockwood G; Minden MD; Messner HA 《Blood》1987,69(5):1307-1314
A culture system has been developed that promotes growth of clonogenic lymphoma cells of some patients with intermediate and high-grade malignant lymphoma. The formation of colonies in bone marrow, lymph nodes, and peripheral blood samples is best supported by human plasma. Colony formation of some patients was dependent upon growth factors, which in this study were added in the form of medium conditioned by phytohemagglutinin (PHA)-stimulated leukocytes (PHA-LCM). Some gave rise to lymphoma colonies without PHA-LCM but improved their frequency with PHA-LCM; others were completely independent of PHA-LCM. Colonies grown in primary cultures were routinely recloned and propagated as Epstein-Barr virus (EBV)-negative cell lines with stable B cell phenotype. The cell lines showed the same immunoglobulin rearrangement pattern as that observed in the primary lymphoma sample. In addition, a significant clinical correlation was observed between culture data and clinical outcome. Survival of patients who formed lymphoma colonies at any time during their clinical course was significantly shorter than survival of patients who did not give rise to colonies (P = 0.0009). The same observation was made when the survival assessment was performed for the subset of patients studied at diagnosis (P = 0.0014). 相似文献
126.
F reticulocyte response in sickle cell anemia treated with recombinant human erythropoietin: a double-blind study 总被引:1,自引:0,他引:1
Nagel RL; Vichinsky E; Shah M; Johnson R; Spadacino E; Fabry ME; Mangahas L; Abel R; Stamatoyannopoulos G 《Blood》1993,81(1):9-14
Studies on baboons and preliminary observations in three patients with sickle cell anemia (SS) suggested that high doses of pulse administered recombinant human erythropoietin (rHuEPO) stimulate F-reticulocyte production. We now report on the administration of rHuEPO in a double- blind format to ascertain frequency of response and potential precipitation of side effects. Ten patients were enrolled, but one was discontinued due to the indication of a blood transfusion. Of the other nine, five received rHuEPO in escalating doses (from 400 to 1,500 U per kg twice daily [BID] per week), alternating with a placebo, in blinded fashion. The second group, consisting of four patients, followed an identical protocol (except starting dose was 1,000 U/Kg, BID per week) and were iron supplemented during treatment. The criterion of response was a transient doubling (as a minimum) of the steady-state F- reticulocyte level. We found that none of the five patients in the first group responded to rHuEPO, and two of them became iron deficient, as judged by a significant decrease in ferritin. Of the second group, four patients responded with F-reticulocyte increases. In three patients, open label administration of rHuEPO confirmed the effect. We observed seven painful episodes during this study, two during the EPO administration and five during the placebo arm. Three patients were phlebotomized because the hemoglobin level increased 1.5 g/dL more than steady-state levels. Of the six patients followed-up by percent dense cell determinations, one exhibited increased levels during periods of the treatment, whereas the other five showed no change. No anti-rHuEPO antibodies were detected. We conclude that rHuEPO can stimulate F- reticulocyte response in some patients with sickle cell anemia, without apparent negative clinical side effects. The state of iron stores may be critical. Whether higher doses of rHuEPO and/or a different regimen might induce sustained F cells and fetal hemoglobin increases remains to be determined. 相似文献
127.
Edith H Van den Hooven Frank H Pierik Sjoerd W Van Ratingen Peter YJ Zandveld Ernst W Meijer Albert Hofman Henk ME Miedema Vincent WV Jaddoe Yvonne De Kluizenaar 《Environmental health : a global access science source》2012,11(1):1-11
Background
High temperature and humidity conditions are associated with short-term elevations in the mortality rate in many United States cities. Previous research has quantified this relationship in an aggregate manner over large metropolitan areas, but within these areas the response may differ based on local-scale variability in climate, population characteristics, and socio-economic factors.Methods
We compared the mortality response for 48 Zip Code Tabulation Areas (ZCTAs) comprising Philadelphia County, PA to determine if certain areas are associated with elevated risk during high heat stress conditions. A randomization test was used to identify mortality exceedances for various apparent temperature thresholds at both the city and local scale. We then sought to identify the environmental, demographic, and social factors associated with high-risk areas via principal components regression.Results
Citywide mortality increases by 9.3% on days following those with apparent temperatures over 34°C observed at 7:00 p.m. local time. During these conditions, elevated mortality rates were found for 10 of the 48 ZCTAs concentrated in the west-central portion of the County. Factors related to high heat mortality risk included proximity to locally high surface temperatures, low socioeconomic status, high density residential zoning, and age.Conclusions
Within the larger Philadelphia metropolitan area, there exists statistically significant fine-scale spatial variability in the mortality response to high apparent temperatures. Future heat warning systems and mitigation and intervention measures could target these high risk areas to reduce the burden of extreme weather on summertime morbidity and mortality. 相似文献128.
写好财务分析是财务人员的一项重要工作。2012年的财务分析该怎么写,笔者认为,新医院会计制度下应聚焦3个层面:财务状况有哪些重大变化;经济运营受到哪些重大影响;下一年经济管理该关注哪些重点。通过探讨,旨在提高财务人员的理论分析水平,总体上把握大势,反映真实信息,当好参谋。 相似文献
129.
In vitro evaluation of prothrombin complex concentrates in a thrombin generation assay, using DAPA and purified components of the prothrombinase complex, demonstrated significant levels of coagulant- active "phospholipid replacing" activity. Quantification of this activity showed a significant correlation (r = 0.8747, p less than 0.01) with thrombogenicity measured in vivo in a stasis model in rabbits. Extracted lipid material retained full phospholipid replacing activity in the vitro assay. Thin-layer chromatographic characterization confirmed the presence of phospholipids with known coagulant activity in vitro. In vivo, the extracted material was nonthrombogenic but augmented the thrombogenicity of purified factor Xa. Substitution of a synthetic coagulant-active phospholipid (phosphatidylcholine-phosphatidylserine lipid vesicles) for the extracted phospholipid produced a similar augmentation of a factor-Xa- induced thrombogenicity in vivo. It is concluded that the coagulant- active phospholipid content of prothrombin complex concentrates is a major determinant of thrombogenicity but requires the presence of activated clotting factors for its expression in vivo. 相似文献
130.
Effect of Platform Shift on Crestal Bone Levels and Mucosal Profile Following Flap Surgery and Subcrestal Implant Placement in Presence/Absence of Gap Defects 下载免费PDF全文