全文获取类型
收费全文 | 1936篇 |
免费 | 137篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 49篇 |
妇产科学 | 31篇 |
基础医学 | 232篇 |
口腔科学 | 27篇 |
临床医学 | 276篇 |
内科学 | 365篇 |
皮肤病学 | 43篇 |
神经病学 | 219篇 |
特种医学 | 119篇 |
外科学 | 178篇 |
综合类 | 47篇 |
一般理论 | 3篇 |
预防医学 | 192篇 |
眼科学 | 19篇 |
药学 | 131篇 |
中国医学 | 5篇 |
肿瘤学 | 137篇 |
出版年
2023年 | 14篇 |
2022年 | 44篇 |
2021年 | 79篇 |
2020年 | 44篇 |
2019年 | 69篇 |
2018年 | 64篇 |
2017年 | 43篇 |
2016年 | 43篇 |
2015年 | 56篇 |
2014年 | 57篇 |
2013年 | 100篇 |
2012年 | 84篇 |
2011年 | 106篇 |
2010年 | 37篇 |
2009年 | 57篇 |
2008年 | 84篇 |
2007年 | 62篇 |
2006年 | 71篇 |
2005年 | 53篇 |
2004年 | 68篇 |
2003年 | 65篇 |
2002年 | 56篇 |
2001年 | 42篇 |
2000年 | 49篇 |
1999年 | 32篇 |
1998年 | 24篇 |
1997年 | 30篇 |
1996年 | 24篇 |
1995年 | 24篇 |
1994年 | 15篇 |
1993年 | 14篇 |
1992年 | 39篇 |
1991年 | 23篇 |
1990年 | 38篇 |
1989年 | 46篇 |
1988年 | 29篇 |
1987年 | 26篇 |
1986年 | 27篇 |
1985年 | 36篇 |
1984年 | 23篇 |
1983年 | 14篇 |
1982年 | 13篇 |
1981年 | 16篇 |
1979年 | 10篇 |
1978年 | 11篇 |
1977年 | 18篇 |
1975年 | 11篇 |
1971年 | 9篇 |
1969年 | 8篇 |
1967年 | 9篇 |
排序方式: 共有2079条查询结果,搜索用时 0 毫秒
41.
Rubins Daniel J Meng Xiangjun McQuade Paul Klimas Michael Getty Krista Lin Shu-An Connolly Brett M. O’Malley Stacey S. Haley Hyking Purcell Mona Gantert Liza Holahan Marie Lindgren Joel Eklund Pär Ekblad Caroline Frejd Fredrik Y. Hostetler Eric D. González Trotter Dinko E. Evelhoch Jeffrey L. 《Molecular imaging and biology》2021,23(2):241-249
Molecular Imaging and Biology - In vivo imaging of programmed death ligand 1 (PD-L1) during immunotherapy could potentially monitor changing PD-L1 expression and PD-L1 expression heterogeneity... 相似文献
42.
Interactions of a Photo-Affinity ATP Analog with Cation-Stimulated Adenosine Triphosphatases of Human Red Cell Membranes 总被引:10,自引:9,他引:10 下载免费PDF全文
Boyd E. Haley Joseph F. Hoffman 《Proceedings of the National Academy of Sciences of the United States of America》1974,71(9):3367-3371
To identify and isolate ATP binding and hydrolyzing sites of human red cell membranes we have synthesized a photo-activated ATP analog, 8-azido adenosine triphosphate (N3ATP). In the absence of ultraviolet light it is a substrate for both the Mg-ATPase and the ouabain-sensitive, Na,K-ATPase. Hydrolysis of N3ATP is prevented by increasing concentrations of ATP. Photolysis of N3ATP with red cell membranes results in covalent incorporation and irreversible inhibition of both ATPase activities. Also, only three protein components of the red cell membranes are labeled. This labeling is completely abolished by appropriate concentrations of ATP. 相似文献
43.
Ether lipids (EL) and hyperthermia have been shown to possess a relatively selective cytotoxicity to leukemic cells. In this study, the combined effects of EL (ET-18-OCH3, ET-16-NHCOCH3, or BM 41.440) and hyperthermia on the growth of hematopoietic progenitors, myeloid leukemic cell lines, and leukemic cells obtained from patients with acute myeloid leukemia (AML) were examined to determine if this combination resulted in a greater selective killing of leukemic cells than that achieved by either EL or heat alone. When the cells were treated simultaneously with EL (50 micrograms/mL) and hyperthermia (42 degrees C) for one hour, the killing of leukemic cell line cells was enhanced considerably. Among the three EL, however, the combination of ET-18-OCH3 and heat seemed to be the most cytotoxic to leukemic cell line cells with no effect on the growth of hematopoietic progenitors. An increase in the duration of treatment with ET-18-OCH3 to four hours with heat added during the last hour resulted in a further reduction of leukemic cell line cells while sparing 50% of hematopoietic progenitors after cryopreservation. The combined treatment with ET-18-OCH3 and heat also inhibited the growth of leukemic progenitors obtained from AML patients by 97% to 100%. These data indicate that the combined treatment with EL and hyperthermia might offer an efficient means to eliminate myeloid leukemic cells in vitro. 相似文献
44.
45.
46.
Zhiling Guo Yiu Chung Tse Ying Zhang Qiang Sun Haley A. Vecchiarelli Robert Aukema Matthew N. Hill Tak Pan Wong Patricia Boksa 《European neuropsychopharmacology》2018,28(12):1405-1417
There is strong evidence that immune activation from prenatal infection increases the risk for offspring to develop schizophrenia. The endocannabinoid (eCB) system has been implicated in the pathophysiology of schizophrenia while models of cortical dysfunction postulate an imbalance between neuronal excitation and inhibition in the disorder. The current study examined the impact of prenatal immune activation on eCB-mediated inhibitory mechanisms. We compared two forms of eCB-related plasticity of evoked inhibitory postsynaptic currents, namely depolarization-induced suppression of inhibition (DSI) and metabotropic glutamate receptor-induced long term depression (mGluR-iLTD), in both the dorsal and ventral hippocampus between adolescent offspring from rat dams that received either saline or bacterial lipopolysaccharide (LPS) during pregnancy. Compared to prenatal saline offspring, prenatal LPS offspring displayed prolonged DSI and stronger mGluR-iLTD in the dorsal and ventral hippocampus, respectively. The sensitivity of mGluR-iLTD to the CB1 receptor antagonist AM251 was also lower in the dorsal hippocampus of prenatal LPS compared to prenatal saline offspring. Testing whether changes in eCB receptor signaling or levels could contribute to these changes in inhibitory transmission, we found region specific increases in 2-arachidonoylglycerol-stimulated signaling and in basal and mGluR-induced levels of anandamide in prenatal LPS offspring when compared to prenatal saline offspring. Our findings indicate that prenatal immune activation can lead to long-term changes in eCB-related plasticity of hippocampal inhibitory synaptic transmission in adolescent rat offspring. Perturbation of the eCB system resulting from prenatal immune activation could represent a mechanism linking early life immune events to the development of psychopathology in adolescence. 相似文献
47.
Haley M. Kolp Alexandra R. Hershberger Jasmyn Sanders Miji Um Melissa A. Cyders 《Substance use & misuse》2018,53(8):1252-1259
Conduct disorder (CD) symptoms cooccur at high rates with illicit drug use in juvenile justice involved youth, which results in poorer outcomes; however, research has not identified where best to intervene in this relationship, limiting the identification of modifiable risk factors to reduce negative effects of CD symptoms. Two mediation models were examined to investigate the potential for CD symptoms to influence a reciprocal relationship between illicit drug use and positive drug attitudes, controlling for age, gender, and race. Data were examined for 245 juvenile justice involved youth (mean age = 15.46, SD = 1.30, range 12–18, 64.9% Black, 80.4% male) who completed court-ordered psychological assessments. Findings indicate: (1) Positive attitudes toward illicit drug use significantly mediated the relationship between CD symptoms and illicit drug use (β = 0.16, CI 0.09–0.27; test for indirect effect z = 4.17, p < .001) and (2) illicit drug use significantly mediated the relationship between CD symptoms and positive attitudes toward illicit drug use (β = 0.20, CI 0.12–0.32; test for indirect effect z = 4.87, p < .001). Overall, the present study suggests that CD symptoms impart risk for illicit drug use both indirectly, through more positive attitudes toward illicit drug use, and directly, which further strengthens positive attitudes toward illicit drug use. 相似文献
48.
49.
Collin York Christopher Olm Ashley Boller Leo McCluskey Lauren Elman Jenna Haley Emily Seltzer Lama Chahine John Woo Katya Rascovsky Corey McMillan Murray Grossman 《Journal of neurology》2014,261(6):1073-1079
Patients with amyotrophic lateral sclerosis (ALS) have a motor disorder and cognitive difficulties, including difficulty with action verbs. However, the basis for the action verb impairment is unknown. Thirty-six participants with ALS and 22 with Parkinson’s disease (PD) were assessed on a simple, two-alternative forced-choice associativity judgment task, where performance was untimed and did not depend on motor functioning. We probed 120 frequency-matched action verbs, cognition verbs, concrete nouns and abstract nouns. Performance was related to T1 MRI imaging of gray matter atrophy. Patients with ALS were significantly impaired relative to healthy senior control participants only for action verbs. Patients with PD did not differ from controls for all word categories. Regression analyses related action verb performance in ALS to motor-associated cortices, but action verb judgments in PD were not related to cortical atrophy. These findings are consistent with the hypothesis that action verb difficulty in ALS is related in part to the degradation of action-related conceptual knowledge represented in motor-associated cortex. 相似文献
50.
Haley M Cui X Minneci PC Deans KJ Natanson C Eichacker PQ 《The American journal of the medical sciences》2004,328(4):215-219
Based on the results of the phase III PROWESS trial, recombinant human activated protein C (rhAPC) was approved by the Food and Drug Administration (FDA) for use in severely septic patients. Concerns regarding rhAPC's inconsistent effects, incomplete understanding of its mechanism of action, and its safety in particular subgroups were raised during the FDA's evaluation. This study attempts to assess the cost-effectiveness rhAPC by comparing its effects during recent clinical use to its prior phase III trial testing and by considering other potentially less expensive treatments with effects that may overlap those of rhAPC. In patients with similar numbers of injured organs, mortality rates may be higher with rhAPC during clinical use compared with the phase III trial. There may also be an increased risk of hemorrhage and other adverse events that necessitate early discontinuation of treatment. Many of the patients receiving rhAPC during clinical use may have otherwise been excluded from its phase III trial testing. Data from several recent phase III trials as well as a recent meta-analysis suggest that heparin and physiologic dose steroids offer substantially less expensive alternatives to rhAPC. Further phase IV testing will be required to confirm such possibilities. 相似文献