全文获取类型
收费全文 | 722篇 |
免费 | 47篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 100篇 |
儿科学 | 42篇 |
妇产科学 | 8篇 |
基础医学 | 42篇 |
口腔科学 | 17篇 |
临床医学 | 69篇 |
内科学 | 118篇 |
皮肤病学 | 5篇 |
神经病学 | 9篇 |
特种医学 | 182篇 |
外科学 | 61篇 |
综合类 | 44篇 |
预防医学 | 22篇 |
眼科学 | 4篇 |
药学 | 16篇 |
1篇 | |
肿瘤学 | 42篇 |
出版年
2021年 | 10篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 14篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 13篇 |
2013年 | 5篇 |
2012年 | 15篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 18篇 |
2008年 | 12篇 |
2007年 | 24篇 |
2006年 | 19篇 |
2005年 | 19篇 |
2004年 | 11篇 |
2003年 | 17篇 |
2002年 | 10篇 |
2001年 | 13篇 |
2000年 | 7篇 |
1999年 | 11篇 |
1998年 | 27篇 |
1997年 | 25篇 |
1996年 | 20篇 |
1995年 | 26篇 |
1994年 | 21篇 |
1993年 | 35篇 |
1992年 | 11篇 |
1991年 | 15篇 |
1990年 | 19篇 |
1989年 | 26篇 |
1988年 | 25篇 |
1987年 | 39篇 |
1986年 | 24篇 |
1985年 | 29篇 |
1984年 | 12篇 |
1983年 | 13篇 |
1982年 | 9篇 |
1981年 | 17篇 |
1980年 | 15篇 |
1979年 | 6篇 |
1978年 | 14篇 |
1977年 | 6篇 |
1976年 | 10篇 |
1975年 | 18篇 |
1974年 | 6篇 |
1973年 | 7篇 |
1972年 | 10篇 |
1971年 | 8篇 |
排序方式: 共有782条查询结果,搜索用时 15 毫秒
71.
Michael D. April Jose Aguirre Lloyd I. Tannenbaum Tyler Moore Alexander Pingree Robert E. Thaxton Daniel J. Sessions James H. Lantry 《The Journal of emergency medicine》2017,52(5):622-631
Background
Quick Sequential Organ Failure Assessment (qSOFA) is a prognostic score for patients with sepsis.Objective
Our aim was to compare the area under the receiver operating curve (AUROC), sensitivity, specificity, and likelihood ratios of qSOFA vs. systemic inflammation response syndrome (SIRS) in predicting in-hospital mortality among emergency department (ED) patients with suspected infection admitted to intensive care units (ICUs).Methods
We conducted a retrospective cohort chart review study of ED patients admitted to an ICU with suspected infection from August 1, 2012 to February 28, 2015. We included all patients with body fluid cultures sampled either during their ED stay without antibiotic administration or within 24 h of antibiotics administered in the ED. Trained chart abstractors blinded to the study hypothesis double-entered data from each patient's electronic medical record including demographic characteristics, vital signs, laboratory study results, physical examination findings, and in-hospital mortality. We then calculated the AUROC, sensitivity, specificity, and likelihood ratios for qSOFA and SIRS for predicting in-hospital mortality.Results
Of 214 patients admitted to an ICU with presumed sepsis, 39 (18.2%) died during hospitalization. The AUROC value was 0.65 (95% confidence interval [CI] 0.56–0.74) for SIRS vs. 0.66 (95% CI 0.57–0.76) for qSOFA; 2+ qSOFA criteria predicted in-hospital mortality with 89.7% sensitivity, 27.4% specificity, 1.2 positive likelihood ratio, and 0.4 negative likelihood ratio.Conclusions
Among ED patients admitted to an ICU, the SIRS and qSOFA criteria had comparable prognostic value for predicting in-hospital mortality. These prognostic values are similar to those reported by the Sepsis-3 guidelines for ICU encounters. 相似文献72.
73.
74.
The Viral Activation Transfusion Study (VATS): rationale, objectives, and design overview 总被引:1,自引:0,他引:1
75.
BACKGROUND: JMH is a high-frequency red cell blood group antigen that resides on a 76- to 80-kDa glycosylphosphatidylinositol-linked protein also known as CDw108. Antibodies with JMH specificity are often autoimmune and are usually, if not always, clinically benign. Some individuals with JMH-variant antigen produce alloantibodies to JMH, but little evidence concerning their clinical significance is available. This article reports on two patients who express a JMH-variant antigen and produced alloanti-JMH. STUDY DESIGN AND METHODS: Murine monoclonal antibodies and human antibodies to JMH were used in hemagglutination, radioimmunoassay, and Western blot testing of red cells from two JMH- variant patients; antiserum from one of these patients was also used in biochemical studies. In addition, in vivo survival of JMH-positive red cells was studied in the same patient. RESULTS: Biochemically, both examples of red cells with the JMH-variant phenotype expressed a JMH protein with a molecular weight similar to that of the normal JMH protein. For both patients, family studies suggested an autosomal recessive pattern of inheritance. Survival study demonstrated reduced in vivo red cell survival in one patient. CONCLUSION: JMH-variant phenotypes express a protein of normal molecular weight and are inherited in an autosomal recessive pattern. Furthermore, individuals with this phenotype can produce clinically significant antibodies. 相似文献
76.
Kidney transplants in mice. An analysis of the immune status of mice bearing long-term, H-2 incompatible transplants
下载免费PDF全文
![点击此处可从《The Journal of experimental medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kidney transplants between strains of mice which are incompatible at either the K or the D end of the H-2 complex usually function for prolonged periods supporting the lives of nephrectomized recipients. This occurs with no recipient treatment. With multiple H-2 and non-H-2 determined incompatibilities, transplants may be rejected but more slowly than skin grafts. In the strain combination studied most extensively in these experiments (B10.D2 to B6AF(1)) in which the incompatibility was confined to the K end of the H-2 region, about 70 percent of recipients survived for many weeks with normal blood urea nitrogen levels. Skin grafts between untreated members of these strains were rejected promptly (mean survival time of 13.5 +/- 1.1 days) as were kidney transplants to recipients of prior skin grafts. Donor strain skin grafts to recipients of kidney transplants after kidney transplantation enjoyed greatly prolonged survival whereas skin grafts from a third party (A.SW) were rejected normally. If kidney tissue was transferred in the form of free grafts without primary vascular union, it was rejected promptly leaving its recipient highly immunized. Cellular and humoral immunity to donor antigens declined over the first few weeks after transplantation, and the spleens of long-term recipients contained no “killer cells.” Recipient lymphoid cells could mount active graft versus host reactions to donor strain antigens on transfer to neonatal mice. Nevertheless, they were distinctly less able to respond specifically by the production of killer cells to donor strain antigens after sensitization in vitro. No evidence that this defect was associated with the presence of suppressor cells was forthcoming from several types of in vivo and in vitro tests. 相似文献
77.
目的:建立概率预测的Logistic回归模型,分析影响神经原性膀胱尿动力学的主要危险因素和保护因素,并评价模型的灵敏度、特异度和准确性。方法:收集2004-03/2006-03在中山大学附属第一医院尿流动力学室行尿动力学检查的患者80例,对其尿动力学图的客观指标进行回顾性分析。①80例中尿流动力学图正常者29例为对照组,尿流动力学图显示神经原性膀胱者51例为病例组。②将两组资料采用统一的变量指标(包括性别、年龄以及尿流动力学仪器自动采集计算的34个数据)输入SPSS12.0版本数据库,进行主成分分析,将贡献率高的主成分进行单因素分析,取其中有统计学意义的主成分作多因素Logistic回归分析,建立Logistic回归方程,计算各因素的OR值,并计算模型的灵敏度、特异度和准确度。结果:①尿动力学34个客观指标进行主成分分析后得出8个主成分(C1~8),取贡献率高的5个主成分进行单因素分析,结果有2个主成分可以进入多因素Logistic回归分析。获得Logistic回归概率预测模型,此概率预测模型灵敏度为82.4%,特异度75.9%,准确度为80.0%。②主成分C1的OR值=4.606,C1中的首次尿意膀胱压力和逼尿肌压力、正常尿意膀胱压力和逼尿肌压力、强烈尿意膀胱压力和逼尿肌压力、尿急尿意膀胱压力和逼尿肌压力、充盈期最大逼尿肌压力的系数分别是0.823,0.834,0.781,0.913,0.924,0.932,0.883,0.916,0.857,高于C1中其他变量的系数,故可把主成分C1看作是一个“压力型”指标。③C3的OR值=0.183,C3中系数较高的变量是最大流率、平均流率、压力流率中最大流率和平均流率,分别是0.694,0.777,0.768,0.771,因此把C3看作为“流率”变量指标。结论:①成功构建了人神经原性膀胱尿流动力学图的概率预测模型,其中“压力”因子主成分是危险因素,“流率”因子主成分是保护因素。②概率预测模型的灵敏度、特异度和准确性显示其有较好的代表性。 相似文献
78.
Ultraviolet-B (UV-B) irradiation of platelet concentrates (PCs) may prevent the development of posttransfusion HLA alloimmunization. This study evaluated the effect of increasing doses of UV-B radiation on stored PCs. Pooled PCs were irradiated at UV-B doses of 600, 2400 or 10,000 mJ per cm2 and stored up to 96 hours under standard blood bank conditions. Compared to nonirradiated room-temperature and 37 degrees C controls, the irradiated units showed no significant changes in platelet count, white cell count, discharge of lactate dehydrogenase, release of beta-thromboglobulin, metabolism of ATP, ADP, ammonia, glutamine, glutamate, hypoxanthine, pCO2, or pO2 at any time of storage following any of the three UV-B doses. However, after a dose of 10,000 mJ per cm2, there were significant decreases in in vitro assays of platelet function-specifically, osmotic recovery and morphology score. Some metabolic systems were also affected by the 10,000 mJ per cm2 radiation dose, as shown by a decline in pH and bicarbonate and an increase in glucose consumption and lactate production (p < 0.05). The changes in these latter assays appeared only after 96 hours of postirradiation storage. Such changes were not seen in either the room- temperature or 37 degrees C control groups. Thus, heat generated during irradiation, per se, did not appear responsible for the observed in vitro changes in platelet function and metabolism. On the basis of the assays analyzed, it is concluded that UV-B irradiation of PCs at doses up to 10,000 mJ per cm2 does not induce significant metabolic or functional derangements following short-term storage (24-48 hours).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
79.
LD Petz ; L Calhoun ; P Yam ; M Cecka ; G Schiller ; AR Faitlowicz ; R Herron ; D Sayah ; RB Wallace ; A Belldegrun 《Transfusion》1993,33(9):742-750
A patient without evident immune deficiency who received a transfusion of blood from a second-degree family member developed fatal transfusion- associated graft-versus-host disease (TA-GVHD). The donor was homozygous for an HLA haplotype for which the recipient was heterozygous (one-way HLA match). All 39 reported cases of TA-GVHD in immunocompetent patients were reviewed to ascertain the predisposing factors and to define the indications for irradiating blood for this population. HLA typing was described in 15 cases; in 13, including seven related and six unrelated donors, a one-way HLA match was present. Thirty-one (79%) of the 39 cases were reported from Japan (and 196 other cases are cited in the Japanese literature), but a one-way HLA match among unrelated donors at HLA-A, -B, -DR loci is only approximately two to four times more likely in Japanese persons than in whites. Fresh blood (< 96 hours old) was used in 29 (94%) of the 31 cases reported from Japan and in 33 (87%) of 38 cases overall (in one case, the age of the blood used was not reported). Thus, factors that appear to predispose to TA-GVHD in immunocompetent patients are a one- way HLA match, fresh blood, and, possibly, Japanese ancestry. Irradiating cellular blood components from all blood relatives of transfusion recipients will not completely eliminate the risk of TA- GVHD. 相似文献
80.
Rashby SE Sessions AL Summons RE Newman DK 《Proceedings of the National Academy of Sciences of the United States of America》2007,104(38):15099-15104
Sedimentary 2-methyhopanes have been used as biomarker proxies for cyanobacteria, the only known bacterial clade capable of oxygenic photosynthesis and the only group of organisms found thus far to produce abundant 2-methylbacteriohopanepolyols (2-MeBHPs). Here, we report the identification of significant quantities of 2-MeBHP in two strains of the anoxygenic phototroph Rhodopseudomonas palustris. Biosynthesis of 2-MeBHP can occur in the absence of O(2), deriving the C-2 methyl group from methionine. The relative abundance of 2-MeBHP varies considerably with culture conditions, ranging from 13.3% of total bacteriohopanepolyol (BHP) to trace levels of methylation. Analysis of intact BHPs reveals the presence of methylated bacteriohopane-32,33,34,35-tetrol but no detectable methylation of 35-aminobacteriohopane-32,33,34-triol. Our results demonstrate that an anoxygenic photoautotroph is capable of generating 2-MeBHPs and show that the potential origins of sedimentary 2-methylhopanoids are more diverse than previously thought. 相似文献