全文获取类型
收费全文 | 31128篇 |
免费 | 3141篇 |
国内免费 | 2056篇 |
专业分类
耳鼻咽喉 | 279篇 |
儿科学 | 363篇 |
妇产科学 | 392篇 |
基础医学 | 3623篇 |
口腔科学 | 538篇 |
临床医学 | 4026篇 |
内科学 | 4723篇 |
皮肤病学 | 325篇 |
神经病学 | 1793篇 |
特种医学 | 1141篇 |
外国民族医学 | 25篇 |
外科学 | 3233篇 |
综合类 | 5146篇 |
现状与发展 | 6篇 |
一般理论 | 1篇 |
预防医学 | 2282篇 |
眼科学 | 681篇 |
药学 | 3281篇 |
32篇 | |
中国医学 | 1754篇 |
肿瘤学 | 2681篇 |
出版年
2024年 | 144篇 |
2023年 | 600篇 |
2022年 | 1415篇 |
2021年 | 1830篇 |
2020年 | 1361篇 |
2019年 | 1124篇 |
2018年 | 1197篇 |
2017年 | 1102篇 |
2016年 | 971篇 |
2015年 | 1468篇 |
2014年 | 1790篇 |
2013年 | 1594篇 |
2012年 | 2297篇 |
2011年 | 2492篇 |
2010年 | 1467篇 |
2009年 | 1173篇 |
2008年 | 1583篇 |
2007年 | 1469篇 |
2006年 | 1503篇 |
2005年 | 1444篇 |
2004年 | 1019篇 |
2003年 | 831篇 |
2002年 | 833篇 |
2001年 | 663篇 |
2000年 | 682篇 |
1999年 | 790篇 |
1998年 | 480篇 |
1997年 | 447篇 |
1996年 | 347篇 |
1995年 | 306篇 |
1994年 | 226篇 |
1993年 | 173篇 |
1992年 | 235篇 |
1991年 | 196篇 |
1990年 | 167篇 |
1989年 | 162篇 |
1988年 | 139篇 |
1987年 | 132篇 |
1986年 | 116篇 |
1985年 | 99篇 |
1984年 | 45篇 |
1983年 | 33篇 |
1982年 | 21篇 |
1981年 | 19篇 |
1980年 | 16篇 |
1979年 | 18篇 |
1978年 | 12篇 |
1974年 | 9篇 |
1971年 | 10篇 |
1970年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
91.
Identification of two mutations in a compound heterozygous child with dihydrolipoamide dehydrogenase deficiency 总被引:1,自引:0,他引:1
Hong YS; Kerr DS; Craigen WJ; Tan J; Pan Y; Lusk M; Patel MS 《Human molecular genetics》1996,5(12):1925-1930
An infant girl with elevated blood lactate, pyruvate, and plasma
branched-chain amino acids was diagnosed with dihydrolipoamide
dehydrogenase (E3; dihydrolipoamide: NAD+ oxidoreductase, EC 1.8.1.4)
deficiency. Activities of the pyruvate dehydrogenase complex and E3 from
patient were 26 and 2% of controls in blood lymphocytes, and 11 and 14% in
cultured skin fibroblasts, respectively. Western blot analysis demonstrated
that the amount of E3 protein in fibroblasts from the patient and her
father was about half of controls, while Northern blot analysis showed
normal amounts of E3 RNA. DNA sequencing of cloned full-length E3 cDNAs
from the patient revealed two mutations in separate alleles. One is a
single base insertion of an extra adenine in the last codon of the leader
peptide sequence (TAC-->TAAC) leading to a nonsense mutation which
results in the premature termination of the precursor E3 polypeptide
(Y35X). The other is a missense mutation due to substitution of guanine for
adenine, causing an Arg-->Gly substitution at amino acid 460 of the
mature protein (R460G) which triggers the loss of E3 activity probably by
structural change in the E3 dimer. DNA sequencing of E3 cDNAs from the
parents demonstrated that the nonsense mutation was inherited from the
father and the missense mutation was inherited from the mother.
相似文献
92.
Nina Yao Jennifer Turner Zvi Kelman P. Todd Stukenberg Frank Dean David Shechter Zhen-Qiang Pan Jerard Hurwitz Mike O'Donnell 《Genes to cells : devoted to molecular & cellular mechanisms》1996,1(1):101-113
Background: The high speed and processivity of replicative DNA polymerases reside in a processivity factor which has been shown to be a ring-shaped protein. This protein (‘sliding clamp’) encircles DNA and tethers the catalytic unit to the template. Although in eukaryotic, prokaryotic and bacteriophage-T4 systems, the processivity factors are ring-shaped, they assume different oligomeric states. The Escherichia coli clamp (the β subunit) is active as a dimer while the eukaryotic and T4 phage clamps (PCNA and gp45, respectively) are active as trimers. The clamp can not assemble itself on DNA. Instead, a protein complex known as a clamp loader utilizes ATP to assemble the ring around the primer-template. This study compares properties of the human PCNA clamp with those of E. coli and T4 phage. Results: The PCNA ring is a stable trimer down to a concentration below 100 nm (Kd ≈ 21 nm ). On DNA, the PCNA clamp slides freely and dissociates from DNA slowly (t1/2 ≈ 24 min). β is more stable in solution (Kd < 60 pm ) and on DNA (t1/2 ≈ 1 h) than PCNA which may be explained by its simpler oligomeric state. The T4 gp45 clamp is a much less stable trimer than PCNA (Kd ≈ 250 nm ) and requires association with the polymerase to stabilize it on DNA as observed previously. The consequence of this cooperation between clamp and polymerase is that upon finishing a template and dissociation of the polymerase from DNA, the gp45 clamp spontaneously dissociates from DNA without assistance. However, the greater stability of the PCNA and β clamps on DNA necessitates an active process for their removal. The clamp loaders (RF-C and γ complex) were also capable of unloading their respective clamps from DNA in the presence of ATP. Conclusions: The stability of the different clamps in solution correlates with their stability on DNA. Thus, the low stability of the T4 clamp explains the inability to isolate gp45 on DNA. The stability of the PCNA and β clamps predicts they will require an unloading factor to recycle them on and off DNA during replication. The clamp loaders of PCNA and β double as clamp unloaders presumably for the purpose of clamp recycling. 相似文献
93.
94.
Wang Min Huang Cheng Shen Xin Zhang Yangyi Zhang Zurong Li Jing Zhao Genming Pan Qichao Jiang Yuan 《Zeitschrift fur Gesundheitswissenschaften》2022,30(5):1055-1062
Journal of Public Health - To investigate the attack rate of active tuberculosis (TB) cases and detection rate of latent tuberculosis infection (LTBI) cases, and to identify possible factors... 相似文献
95.
Health Care Management Science - With the implementation of a series of pro-competition policies in China, the hospital market competition has been intensified dramatically over the past decade.... 相似文献
96.
Michael P. Cary Farica Zhuang Rachel Lea Draelos Wei Pan Sathya Amarasekara Brian J. Douthit Yunah Kang Cathleen S. Colón-Emeric 《Journal of the American Medical Directors Association》2021,22(2):291-296
ObjectivesTo evaluate a machine learning model designed to predict mortality for Medicare beneficiaries aged >65 years treated for hip fracture in Inpatient Rehabilitation Facilities (IRFs).DesignRetrospective design/cohort analysis of Centers for Medicare & Medicaid Services Inpatient Rehabilitation Facility–Patient Assessment Instrument data.Setting and ParticipantsA total of 17,140 persons admitted to Medicare-certified IRFs in 2015 following hospitalization for hip fracture.MeasuresPatient characteristics include sociodemographic (age, gender, race, and social support) and clinical factors (functional status at admission, chronic conditions) and IRF length of stay. Outcomes were 30-day and 1-year all-cause mortality. We trained and evaluated 2 classification models, logistic regression and a multilayer perceptron (MLP), to predict the probability of 30-day and 1-year mortality and evaluated the calibration, discrimination, and precision of the models.ResultsFor 30-day mortality, MLP performed well [acc = 0.74, area under the receiver operating characteristic curve (AUROC) = 0.76, avg prec = 0.10, slope = 1.14] as did logistic regression (acc = 0.78, AUROC = 0.76, avg prec = 0.09, slope = 1.20). For 1-year mortality, the performances were similar for both MLP (acc = 0.68, AUROC = 0.75, avg prec = 0.32, slope = 0.96) and logistic regression (acc = 0.68, AUROC = 0.75, avg prec = 0.32, slope = 0.95).Conclusion and ImplicationsA scoring system based on logistic regression may be more feasible to run in current electronic medical records. But MLP models may reduce cognitive burden and increase ability to calibrate to local data, yielding clinical specificity in mortality prediction so that palliative care resources may be allocated more effectively. 相似文献
97.
目的探讨基于胸痛中心急救流程在急性心肌梗死(AMI)患者救治中的应用效果。 方法选取镇江市急救中心2017年8月至2021年8月接诊的94例AMI患者为研究对象,其中男性50例,女性44例;年龄42~81岁,平均(60.37±4.31)岁。根据就诊顺序分为对照组和研究组,每组各47例,对照组患者接受常规急救流程,研究组患者接受基于胸痛中心基础上的急救流程,比较两组患者急救各环节时间、不良心血管事件发生率及患者满意度。 结果研究组患者急救各环节时间较对照组更短,两组比较差异有统计学意义(P<0.05);研究组患者不良心血管事件发生率显著低于对照组(6.38%比23.40%),两组比较差异有统计学意义(P<0.05);研究组患者满意度显著高于对照组(93.62%比78.72%),两组比较差异有统计学意义(P<0.05)。 结论基于胸痛中心急救流程可有效缩短急救过程中各环节时间,最大限度降低不良心血管事件发生风险,患者满意度高,对提高AMI患者救治效果、改善预后具有积极意义。 相似文献
98.
大鼠不同程度的急性颅脑损伤后血糖浓度的变化及其预后 总被引:1,自引:0,他引:1
目的 :探讨大鼠不同程度的急性颅脑损伤后血糖浓度的变化及其与预后的关系。方法 :Wistar雄性大鼠 2 0只 ,随机分为 2组 ,A组 :将 5 0 0 g砝码由 35 cm高度自由下落打击大鼠头部 ;B组 :将 5 0 0 g砝码由 2 0 cm高度自由下落打击大鼠头部 ;设自身对照 ,分别测定不同伤情的两组动物伤前及伤后血糖浓度的变化及观察 2 4h内两组动物死亡情况。结果 :A、B组伤后测得的血糖值均显著高于正常值 (P <0 .0 5 ) ;且 A组伤后测得的血糖值又显著高于 B组 (P <0 .0 5 ) ;A组动物死亡 8只 ,B组死亡 1只。结论 :急性颅脑损伤后均有不同程度的血糖升高 ,而且颅脑损伤程度越重 ,血糖值越高 ,死亡率越高。 相似文献
99.
目的 探讨醒脑静对急性重症一氧化碳 (CO)中毒的催醒作用。方法 在急性重症CO中毒常规综合抢救中加入醒脑静并与常规方法进行对比研究。结果 醒脑静治疗组较常规治疗组清醒时间明显缩短 (P <0 .0 1)。结论 醒脑静可作为急性重症CO中毒病人综合抢救中常规用药。 相似文献
100.
目的:探讨超声检查在诊断乳腺典型髓样癌中的临床意义。方法:按严格的病理诊断学标准将病例重新分类为乳腺典型髓样癌和非典型髓样癌,比较两者间声像学特征的异同。结果:32例中有13侧重新诊断为乳腺典型髓样癌;另外19例为非典型髓样癌。13例典型髓样癌患者中的10例边界整齐光滑;全部19例非典型髓样癌病人没有一例边界光滑,或者边界呈锯齿状(16例),或者边界光滑伴局部不规则(3例)。非典型与典型髓样癌间肿瘤边界的规则性有明显的差异。结论:如果超声检查提示肿瘤边界呈锯齿状或肿瘤边界光滑伴局部不规则,应行整个肿瘤的病理评估防止典型髓样癌的过诊断。 相似文献