全文获取类型
收费全文 | 13680篇 |
免费 | 903篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 139篇 |
儿科学 | 512篇 |
妇产科学 | 371篇 |
基础医学 | 2030篇 |
口腔科学 | 201篇 |
临床医学 | 1621篇 |
内科学 | 2523篇 |
皮肤病学 | 323篇 |
神经病学 | 1699篇 |
特种医学 | 315篇 |
外科学 | 1363篇 |
综合类 | 67篇 |
一般理论 | 13篇 |
预防医学 | 1094篇 |
眼科学 | 234篇 |
药学 | 863篇 |
中国医学 | 17篇 |
肿瘤学 | 1235篇 |
出版年
2023年 | 101篇 |
2022年 | 182篇 |
2021年 | 304篇 |
2020年 | 251篇 |
2019年 | 327篇 |
2018年 | 367篇 |
2017年 | 311篇 |
2016年 | 374篇 |
2015年 | 409篇 |
2014年 | 510篇 |
2013年 | 715篇 |
2012年 | 1064篇 |
2011年 | 1028篇 |
2010年 | 639篇 |
2009年 | 558篇 |
2008年 | 871篇 |
2007年 | 900篇 |
2006年 | 890篇 |
2005年 | 844篇 |
2004年 | 770篇 |
2003年 | 710篇 |
2002年 | 682篇 |
2001年 | 89篇 |
2000年 | 54篇 |
1999年 | 120篇 |
1998年 | 166篇 |
1997年 | 135篇 |
1996年 | 103篇 |
1995年 | 106篇 |
1994年 | 66篇 |
1993年 | 76篇 |
1992年 | 51篇 |
1991年 | 55篇 |
1990年 | 48篇 |
1989年 | 29篇 |
1988年 | 36篇 |
1987年 | 24篇 |
1986年 | 28篇 |
1985年 | 31篇 |
1984年 | 32篇 |
1983年 | 36篇 |
1982年 | 42篇 |
1981年 | 23篇 |
1980年 | 34篇 |
1979年 | 31篇 |
1978年 | 19篇 |
1977年 | 20篇 |
1976年 | 28篇 |
1975年 | 17篇 |
1974年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Central Role for Interleukin-4 in Regulating Nitric Oxide-Mediated Inhibition of T-Cell Proliferation and Gamma Interferon Production in Schistosomiasis 总被引:2,自引:0,他引:2
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Elisabeth A. Patton Anne C. La Flamme Joao A. Pedras-Vasoncelos Edward J. Pearce 《Infection and immunity》2002,70(1):177-184
Schistosoma mansoni-infected wild-type (WT) mice develop a Th2 response and chronic disease. In contrast, infected interleukin-4 double-deficient (IL-4(-/-)) mice develop a Th1-like response and an acute, lethal syndrome. Disease severity in these animals correlates with excessive and prolonged production of nitric oxide (NO) associated with enhanced antigen-driven gamma interferon (IFN-gamma) production in the absence of IL-4. Strikingly, splenic lymphocytes from infected IL-4(-/-) mice failed to proliferate as well as those from infected WT mice following stimulation in vitro with antigen or anti-CD3 antibody. Contrary to antigen-driven IFN-gamma responses, anti-CD3 antibody stimulation of splenocytes resulted in significantly less IFN-gamma being produced by CD8 cells from infected IL-4(-/-) mice than by those from infected WT mice or normal mice. NO is largely responsible for the impaired T-cell functions in infected IL-4(-/-) mice, as inhibition of iNOS significantly enhanced proliferation and IFN-gamma production. 相似文献
92.
Partha Biswas Govindsamy Kumaramanickavel Corinne Stoetzel Renaud Quillet Jyotirmay Biswas Elisabeth Lajeunie Dominique Renier Fabienne Perrin‐Schmitt 《American journal of medical genetics. Part A》2002,109(3):218-225
Saethre‐Chotzen syndrome is an autosomal dominant disease characterized by craniosynostosis, ptosis, and limb and external ear abnormalities. Variable expressivity is a well‐known phenomenon in this disorder. A large Indian family has been recently identified as carrying a nonsense TWIST mutation (Q28 X) in 17 members, of whom 16 were examined in detail. Only 4 (25%) of the patients showed patent craniostenosis, namely, oxycephaly. The penetrance of craniosynostosis in this family is lower than previously reported in the literature. Fifteen patients (93%) had moderate to severe ptosis. Minor limb and external ear abnormalities were present in most patients. Eyelid features were the hallmark of the disease for 12 members of the family, suggesting that mutations in TWIST may lead to a phenotype with mainly palpebral features and no craniostenosis. The clinical analysis of this large family clearly illustrates the significant variable expressivity, probably related to haploinsufficiency because of the TWIST mutation. This phenotypic variability remains unclear but could be the result of modifier genes and/or genetic background effect, as noticed previously in the transgenic twist‐null heterozygous mice. © 2002 Wiley‐Liss, Inc. 相似文献
93.
Elisabeth Klemm Gamil Alhakimi Heidrun Schütz 《Macromolecular chemistry and physics.》1993,194(1):353-361
New polymers with an alternating sequence of non-polar aliphatic chains and coronands were synthesized via Diels-Alder addition polymerization of bis(2-pyrones) with bismaleimides; number-average molecular weight M?n: 18000 (vapour pressure osmometry), glass transition temperature T?g: 250°C. The chemical structures of these polymers are supported by NMR spectra and model reactions. The reaction mechanism is discussed. 相似文献
94.
Summary The gene FUR4, coding for the uracil permease in Saccharomyces cerevisiae, was mapped on chromosome II, at a distance of 7.8 cM from the centromere on the right arm of the chromosome. In a first step, we used the chromosome loss mapping method developed by Falco and Botstein (1983) to determine on which chromosome the gene mapped. After the observation that FUR4 was closely linked to GAL10, one of the three genes forming the gal cluster (Bassel and Mortimer 1971), we could determine precisely the position of the gene on chromosome II. 相似文献
95.
After serial passage of adenovirus type 12 in cells of the human melanoma line Nki4 virus mutants with enhanced growth potential have been isolated which carry additional sequences of regularly increasing size at the right end of the genome. DNA sequence analysis was performed'to characterize these genomic alterations as well as those of the previously described Ad12 mutants adapted to growth in the human carcinoma cell line (I. Kruczek, E. Schwarz, and H. zur Hausen (1981)Int. J. Cancer27, 139–143). Duplication of the inverted terminal repetition (ITR) emerged as the common feature of the right terminal alterations of all the mutant genomes analyzed. The sequences present between the ITR repeats were of either right-end or left-end origin, the latter suggesting that left-end sequences comprising the ITR and parts of the adjacent unique sequences have been transferred to the right end of the genome. The different sizes of the additional sequences in Ad12 Nki-4 DNA could be explained by varying degrees of amplification of a basic additional sequence of 342 base pairs. 相似文献
96.
Inge Van de Walle Karen Silence Kevin Budding Liesbeth Van de Ven Kim Dijkxhoorn Elisabeth de Zeeuw Cafer Yildiz Sofie Gabriels Jean-Michel Percier Johanna Wildemann Jan Meeldijk Peter J. Simons Louis Boon Linda Cox Rob Holgate Rolf Urbanus Henny G. Otten Jeanette H.W. Leusen Peter Boross 《The Journal of allergy and clinical immunology》2021,147(4):1420-1429.e7
97.
Hermansky-Pudlak syndrome type 4 in a patient from Sri Lanka with pulmonary fibrosis 总被引:1,自引:0,他引:1
Bachli EB Brack T Eppler E Stallmach T Trüeb RM Huizing M Gahl WA 《American journal of medical genetics. Part A》2004,(2):201-207
Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder characterized by oculocutaneous albinism and a platelet storage pool deficiency. Some patients also develop fatal pulmonary fibrosis and some have granulomatous colitis. Six human genes HPS1, ADB3A, HPS3, HPS4, HPS5, and HPS6 have been identified as cause of the six known subtypes of HPS. While there exist nearly 500 Puerto Rican and non-Puerto Rican HPS-1 patients, very few HPS-4 patients have been reported, and most of these have not been described in detail. We now delineate the clinical characteristics of an HPS-4 patient homozygous for a novel HPS-4 mutation, P685delC. The patient, the first individual with HPS reported from Sri Lanka, had severe pulmonary fibrosis, typical of HPS-1 disease, without granulomatous colitis. We conclude that pulmonary fibrosis occurs as part of HPS-4 and that HPS should be considered in all ethnic groups. 相似文献
98.
The cellular localization of the uptake of [3H]taurine and [3H]β-alanine was studied in cultures of rat central nervous system using autoradiography. In brain stem and spinal cord cultures, both amino acids were taken up by neurones and glial cells. In cerebellar cultures, [3H]taurine was accumulated by all glial cells and by a small number of neurones, whereas [3H]β-alanine was only taken up by glial elements. The uptake of both amino acids was sodium and temperature dependent, indicating an active transport mechanism.The results provide further support for the hypothesis that taurine and β-alanine are neurotransmitters in the mammalian central nervous system. 相似文献
99.
Hordijk José A. Verbruggen Sascha C. Buysse Corinne M. Utens Elisabeth M. Joosten Koen F. Dulfer Karolijn 《Quality of life research》2022,31(9):2615-2617
Quality of Life Research - 相似文献
100.
Magdalena Hoffmann Christine Maria Schwarz Stefan Fürst Christina Starchl Elisabeth Lobmeyr Gerald Sendlhofer Marie-Madlen Jeitziner 《Nutrients》2021,13(1)
Critically ill patients in the intensive care unit (ICU) have a high risk of developing malnutrition, and this is associated with poorer clinical outcomes. In clinical practice, nutrition, including enteral nutrition (EN), is often not prioritized. Resulting from this, risks and safety issues for patients and healthcare professionals can emerge. The aim of this literature review, inspired by the Rapid Review Guidebook by Dobbins, 2017, was to identify risks and safety issues for patient safety in the management of EN in critically ill patients in the ICU. Three databases were used to identify studies between 2009 and 2020. We assessed 3495 studies for eligibility and included 62 in our narrative synthesis. Several risks and problems were identified: No use of clinical assessment or screening nutrition assessment, inadequate tube management, missing energy target, missing a nutritionist, bad hygiene and handling, wrong time management and speed, nutritional interruptions, wrong body position, gastrointestinal complication and infections, missing or not using guidelines, understaffing, and lack of education. Raising awareness of these risks is a central aspect in patient safety in ICU. Clinical experts can use a checklist with 12 identified top risks and the recommendations drawn up to carry out their own risk analysis in clinical practice. 相似文献