全文获取类型
收费全文 | 943篇 |
免费 | 32篇 |
国内免费 | 65篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 54篇 |
妇产科学 | 10篇 |
基础医学 | 68篇 |
口腔科学 | 36篇 |
临床医学 | 139篇 |
内科学 | 252篇 |
皮肤病学 | 23篇 |
神经病学 | 5篇 |
特种医学 | 246篇 |
外科学 | 49篇 |
综合类 | 29篇 |
预防医学 | 30篇 |
眼科学 | 14篇 |
药学 | 38篇 |
肿瘤学 | 45篇 |
出版年
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 8篇 |
2016年 | 6篇 |
2015年 | 15篇 |
2014年 | 14篇 |
2013年 | 24篇 |
2012年 | 13篇 |
2011年 | 11篇 |
2010年 | 29篇 |
2009年 | 44篇 |
2008年 | 17篇 |
2007年 | 61篇 |
2006年 | 30篇 |
2005年 | 22篇 |
2004年 | 17篇 |
2003年 | 12篇 |
2002年 | 17篇 |
2001年 | 13篇 |
2000年 | 11篇 |
1999年 | 16篇 |
1998年 | 62篇 |
1997年 | 70篇 |
1996年 | 70篇 |
1995年 | 60篇 |
1994年 | 42篇 |
1993年 | 49篇 |
1992年 | 9篇 |
1991年 | 14篇 |
1990年 | 13篇 |
1989年 | 39篇 |
1988年 | 22篇 |
1987年 | 36篇 |
1986年 | 12篇 |
1985年 | 24篇 |
1984年 | 15篇 |
1983年 | 23篇 |
1982年 | 19篇 |
1981年 | 17篇 |
1980年 | 20篇 |
1979年 | 1篇 |
1978年 | 5篇 |
1977年 | 9篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1966年 | 2篇 |
1948年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有1040条查询结果,搜索用时 15 毫秒
91.
The need to detect antibodies that agglutinate and/or hemolyze red cells (RBCs) directly at 37 degrees C, but do not react in subsequently performed indirect antiglobulin tests (IATs), is of concern relative to the streamlining and automation of antibody detection methods. To determine incidence and significance of such reactions, data from 87,480 tests, which used low-ionic-strength saline, 10-minute incubation at 37 degrees C, and anti-IgG, were analyzed for unexpected antibodies. There were 3590 positive tests, of which 475 showed reactions at 37 degrees C but not in subsequently performed IATs (37 + IAT-). Of these, 196 reactions were due to autoantibodies or other factors usually considered insignificant with respect to the survival of transfused incompatible RBCs, 176 were due to alloantibodies of questionable clinical significance (M, Lea, P1, etc.), and 103 were associated with alloantibodies of potential clinical significance (63 E, 27 K, 5 Jka, 4 D, 3 cE, and 1 C). This latter reaction was seen in 72 patients, with two 37 + IAT-antibodies occurring in each of 3 patients. Of the 75 potentially significant 37 + IAT-antibodies, 57 were seen in patients recently exposed to homologous RBCs, 13 in patients with a history of transfusion and/or pregnancy, and 5 in patients with no known exposure to homologous RBCs. IAT reactivity was observed in subsequent samples with 27 of these antibodies. The predictive value of a 37 + IAT-test was 21.7 percent for a potentially significant antibody. The incidence was 0.12 percent of all tests for unexpected antibodies.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
92.
93.
A multilaboratory study was conducted to develop a system for standardizing alanine aminotransferase (ALT) acceptability criteria ("cutoffs") for donated blood. Without standardized cutoffs, each laboratory must develop its own cutoff, and this may not make optimal use of ALT testing to reduce transmission of non-A, non-B hepatitis (NANB). Defining an ALT acceptability criterion in absolute terms is necessary because relative cutoffs based on local donor populations may be affected by the prevalence of NANB in each community. This study involved 16 laboratories using 23 different analytic systems. The ALT results of the analysis of a plasma reference sample could be used to translate mathematically a single, absolute cutoff to units applicable to each analytic system. The distribution of ALT results in 1.4 million donations from across the country was established; basing the cutoff on this sample avoids the problems inherent in using a local donor base to establish a cutoff. We propose the implementation of a system to standardize ALT acceptability criteria to an activity level defined by analysis of a nationwide donor sample. 相似文献
94.
Y. LIDÉN O. LANDGREN S. ARNÉR K.‐F. SJÖLUND E. JOHANSSON 《Acta anaesthesiologica Scandinavica》2009,53(3):354-363
Background: Cancer patients undergo numerous invasive diagnostic procedures. However, there are only sparse data on the characteristics and determinants for procedure‐related pain among adult cancer patients. Methods: In this prospective study, we evaluated the characteristics and determinants of procedure‐related pain in 235 consecutive hematologic patients (M/F:126/109; median age 62 years, range 20–89 years) undergoing a bone marrow aspiration/biopsy (BMA) under local anesthesia. Questionnaires were used to assess patients before‐, 10 min and 1–7 days post BMA. Using logistic regression models, we calculated odds ratios (ORs) and 95% confidence intervals (CIs). Results: 165/235 (70%) patients reported pain during BMA; 92 (56%), 53 (32%) and 5 (3%) of these indicated moderate [visual analogue scale (VAS)≥30 mm], severe (VAS>54 mm) and worst possible pain (VAS=100 mm), respectively. On multivariate analyses, pre‐existing pain (OR=2.60 95% CI 1.26–5.36), anxiety about the diagnostic outcome of BMA (OR=3.17 95% CI 1.54–6.52), anxiety about needle‐insertion (OR=2.49 95% CI 1.22–5.10) and low employment status (sick‐leave/unemployed) (OR=3.14 95% CI 1.31–7.55) were independently associated with an increased risk of pain during BMA. At follow‐up 10 min after BMA, 40/235 (17%) patients reported pain. At 1, 3, 6 and 7 days post BMA, pain was present in 137 (64%), 90 (42%), 43 (20%) and 25 (12%) patients, respectively. Conclusions: We found that 3/4 of hematologic patients who underwent BMA reported procedural pain; one third of these patients indicated severe pain. Pre‐existing pain, anxiety about the diagnostic outcome of BMA or needle‐insertion, and low employment status were independent risk factors. 相似文献
95.
Objectives
Obesity is currently a major public health concern; however, there is little data available on the prevalence and impact of obesity within the elderly population. This review examines the prevalence and health effects of obesity among individuals aged ≥50.Methods
PubMed (1996–2008) and PsychInfo (2002–2008) search engines were used to retrieve qualified peer-reviewed articles focusing on obesity or a health condition correlated with obesity using BMI or other weight index as a defining variable; and studies limited to the elderly (age 60+) or pre-elderly (50+).Results
Worldwide, the elderly population is increasingly becoming obese regardless of socio-economic status. Among elderly persons, obesity increases the risks for a variety of morbidity conditions including cancers, diabetes, hypertension, stroke, heart disease, metabolic syndrome, obstructive sleep apnea syndrome, osteoarthritis, depression, disability, and lower scores on quality of life measures. In some reports, obesity has been linked to Alzheimer's disease and other forms of cognitive decline. Obesity significantly increases healthcare costs and nursing homes are currently ill equipped to address the needs of the rising number of obese residents.Conclusions
Obesity is increasing in the elderly population worldwide and is expected to continue to rise. Obesity is associated with disease and disability in addition to escalating healthcare costs, and hospitals and nursing homes are ill equipped to serve the obese elderly. It is imperative that research efforts and funding be devoted to studying the effects and the reduction of obesity in the elderly population. 相似文献96.
Review of the Lynch syndrome: history, molecular genetics, screening, differential diagnosis, and medicolegal ramifications 总被引:1,自引:0,他引:1
Platelets have a central role in the development of arterial thrombosis and subsequent cardiovascular events. An appreciation of this complex process has made antiplatelet therapy the cornerstone of cardiovascular disease management. However, numerous patients will experience a recurrent atherothrombotic vascular event despite adequate antiplatelet therapy. Individual differences in the rate of platelet activation and reactivity markedly influence normal hemostasis and the pathological outcome of thrombosis. Such an individual variability is largely determined by environmental and genetic factors. These are known to either hamper platelets' response to agonists, and thereby mimic the pharmacological modulation of platelet function or mask therapy effect and sensitize platelets. In this article, we reviewed the antiplatelet mechanisms of aspirin and clopidogrel and the possible role of different polymorphisms, which may affect the efficacy of antiplatelet therapy. Heterogeneity in the way patients respond to aspirin and clopidogrel may in part reflect variation in cyclooxygenase (COX)-1, COX-2, glycoprotein (GP) Ib alpha, GP Ia/IIa, GP IIb/IIIa, UGT1A6*2, P2Y1 , P2Y12 , CYP2C9, CYP3A4 and CYP3A5 genotypes. 相似文献
97.
98.
I Sayers J Hawley CE Stewart CK Billington A Henry JR Leighton-Davies SJ Charlton IP Hall 《British journal of pharmacology》2009,158(1):277-286
Background and purpose:
Indacaterol is a novel β2-adrenoceptor agonist in development for the treatment of chronic obstructive pulmonary disease. The aim of this study was to investigate the comparative pharmacology of indacaterol in recombinant cells expressing the common polymorphic variants of the human β2-adrenoceptor and in human primary airway smooth muscle (ASM) cells.Experimental approach:
Chinese hamster ovarian-K1 cell lines expressing high and low levels of the common human β2-adrenoceptor variants were generated [Gly16-Glu27-Val34-Thr164(GEVT), RQVT, GQVT] and also the rare GQVI variant. Human primary ASM cells were isolated from explants of trachealis muscle. Adenosine-3′,5′-cyclic-monophosphate production was used as an outcome measure.Key results:
In both the low- and high-expression recombinant GEVT ‘wild type’ cell lines indacaterol is a high-efficacy agonist. Salmeterol and formoterol were identified as low- and high-efficacy agonists, respectively, and showed similar potencies to indacaterol irrespective of the β2-adrenoceptor genotype. The I164 variant cell line was associated with a reduced capacity to generate adenosine-3′,5′-cyclic-monophosphate in response to β2-adrenoceptor agonist. In the human primary ASM cells indacaterol gave a maximal response intermediate between that of salmeterol and formoterol.Conclusions and implications:
These data demonstrate that indacaterol is a high-efficacy agonist in recombinant cell systems but acts with lower efficacy in human primary ASM cells. No marked genotype-dependent effects were observed for common variants; however, changes in I164 receptor activity were identified, which were dependent on the level of expression of β2-adrenoceptors. 相似文献99.
100.
Arlin ZA; Fanucchi MP; Gee TS; Kempin SJ; Mertelsmann R; Young CW; Clarkson BD 《Blood》1982,60(5):1224-1226
Twenty-four adults with ALL were treated with AMSA alone or in combination. Twenty-two were treated at time of relapse and two patients after failing primary induction therapy. All had been treated with anthracyclines prior to receiving AMSA. Of the 22 patients with ALL in relapse, 4 achieved a complete remission. Two of these patients have relapsed while receiving maintenance chemotherapy; one died 1 mo after achieving remission due to the occurrence of cholycystitis in the setting of pancytopenia and one patient underwent bone marrow transplantation and is in remission at 8 mo after the second remission. Both patients who failed primary induction therapy remain in remission at 11 and 36 mo, respectively. The use of AMSA should be considered for patients with ALL who fail primary induction as well as those whose leukemia becomes resistant to conventional agents. 相似文献