全文获取类型
收费全文 | 14092篇 |
免费 | 923篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 229篇 |
儿科学 | 506篇 |
妇产科学 | 368篇 |
基础医学 | 2066篇 |
口腔科学 | 242篇 |
临床医学 | 1660篇 |
内科学 | 2532篇 |
皮肤病学 | 342篇 |
神经病学 | 1701篇 |
特种医学 | 319篇 |
外科学 | 1392篇 |
综合类 | 69篇 |
一般理论 | 13篇 |
预防医学 | 1122篇 |
眼科学 | 239篇 |
药学 | 905篇 |
中国医学 | 18篇 |
肿瘤学 | 1330篇 |
出版年
2023年 | 103篇 |
2022年 | 183篇 |
2021年 | 308篇 |
2020年 | 250篇 |
2019年 | 340篇 |
2018年 | 370篇 |
2017年 | 313篇 |
2016年 | 377篇 |
2015年 | 414篇 |
2014年 | 515篇 |
2013年 | 729篇 |
2012年 | 1090篇 |
2011年 | 1044篇 |
2010年 | 640篇 |
2009年 | 562篇 |
2008年 | 878篇 |
2007年 | 917篇 |
2006年 | 898篇 |
2005年 | 853篇 |
2004年 | 795篇 |
2003年 | 722篇 |
2002年 | 685篇 |
2001年 | 108篇 |
2000年 | 71篇 |
1999年 | 126篇 |
1998年 | 167篇 |
1997年 | 137篇 |
1996年 | 104篇 |
1995年 | 111篇 |
1994年 | 73篇 |
1993年 | 79篇 |
1992年 | 64篇 |
1991年 | 75篇 |
1990年 | 63篇 |
1989年 | 46篇 |
1988年 | 49篇 |
1987年 | 33篇 |
1986年 | 46篇 |
1985年 | 42篇 |
1984年 | 41篇 |
1983年 | 46篇 |
1982年 | 46篇 |
1981年 | 28篇 |
1980年 | 38篇 |
1979年 | 38篇 |
1978年 | 24篇 |
1977年 | 28篇 |
1976年 | 34篇 |
1974年 | 24篇 |
1972年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Gerda T Noordhoek Jan F L Weel Elisabeth Poelstra Marijke Hooghiemstra Afke H Brandenburg 《Journal of clinical virology》2008,41(2):75-80
BACKGROUND: Enteroviruses (EV) and parechoviruses (HPeV) are the most common causes of aseptic meningitis, encephalitis and sepsis-like syndrome in neonates. Detection by nucleic acid amplification methods improves patient management. OBJECTIVE: Development of a real-time PCR assay on a LightCycler for simultaneous detection of EV, HPeV and an internal control to monitor inhibition. STUDY DESIGN: We investigated the value of the new assay, prospectively, in a variety of samples from patients suspected of having viral meningitis or sepsis-like syndrome. RESULTS: The assay detected 64 EV serotypes and HPeV types 1-4. Of 186 patients, 63 (33.9%) were EV positive and 18 (9.7%) HPeV positive in one or more samples. In 43 of 159 feces and 6 of 57 throat samples viral culture and PCR were positive. With real-time PCR 27 extra EV and 19 HPeV positives were found. Blood and CSF were present from 33 patients. In 19 patients blood and CSF were positive, one was only positive in CSF, two were only positive in blood, 11 were negative. From 96 patients CSF and/or blood samples were tested and compared to results in throat and/or feces samples. Forty patients were EV-PCR and 14 HPeV-PCR positive in blood and/or CSF. All of these were confirmed by a positive PCR for the respective virus in feces and/or throat. CONCLUSIONS: Simultaneous detection of EV and HPeV with this two-step real-time PCR is specific, faster and more sensitive than viral culture. All systemic infections (blood or CSF positive) were confirmed in feces. Culture is no longer necessary for clinical diagnosis and should only be performed on PCR-positive samples to obtain isolates for typing purposes. Application of this assay is an important improvement for patient management since the outcome of the analysis is available within the time frame of clinical decision-making. 相似文献
52.
53.
Thaddeus K. Graczyk Michael R. Cranfield Elisabeth J. Bicknese 《Parasitology research》1995,81(4):316-319
The value profiles of 5 intracellular enzymes, 15 metabolites (with 2 associated ratios), and 3 electrolytes were monitored over time in 9 captive-reared African black-footed penguins (Spheniscus demersus) with different avian malaria clinical status: uninfected, subclinically infected, and clinically infected with fatal outcome. Fatal infections were caused byPlasmodium relictum. Numerous schizonts were visible in the lungs, liver, spleen, and interstitial tissue of the kidneys. The feference ranges of 23 serum clinical chemistry parameters and 2 ratios were established forS. demersus. The mean values obtained for 8 of 23 parameters of the infected penguins were signficantly different from those recorded for the uninfected birds, indicating impaired renal function, hepatic dysfunction, and nonspecific tissue damage related to the infestation with exoerythrocytic schizonts. Analysis of sensitivity, specificity, and negative and positive predictive values (PPVs) showed that gamma-glutamyltranspeptidase (GGTP), alanine aminotransferase (ALT), and creatinine reached PPVs and a specificity over 57% for avian malaria infections in penguins. Creatinine, ALT, and GGTP values should be consulted in evaluation of the clinical malaria status ofS. demersus. 相似文献
54.
In colonic motility disorders, a pathohistological diagnosis based solely on formalin-fixed gut is often inconclusive. Classical histological techniques or immunohistochemistry represent a static staining. In contrast, native tissue submitted to enzyme histochemistry provides functional information about the effectiveness of the cellular performance. Routinely, a complementary set of reactions is performed and includes acetylcholinesterase (AChE), lactic and succinic dehydrogenase, as well as nitroxide synthase reactions. In this monograph, the whole spectrum of different anomalies of the colonic wall is illustrated in a systematic fashion: Hirschsprung's disease is characterized by an increase in AChE activity of parasympathetic nerve fibers of the rectosigmoid. In ultrashort Hirschsprung's disease, only enzyme histochemistry renders a reliable diagnosis possible in biopsies of the anal ring. Aganglionosis of the musculus corrugator cutis ani shows a localized increase of AChE activity in nerve fibers, similar to Hirschsprung's disease, not detectable in conventional histology. Immaturity, hypoganglionosis and neuronal dysganglionosis can be clearly recognized in dehydrogenase reactions. Enzyme histochemical reactions are complemented by picrosirius red staining for assessment of the collagen texture of the muscularis propria. Absence or intertenial interruption of the continuous connective tissue layer between circular and longitudinal muscle of the muscularis propria has been termed aplastic or atrophic desmosis, respectively. Many of the entities described are also observed in adults. Atrophic hypoganglionosis or atrophic desmosis with loss of the myenteric plexus connective tissue fascia is implied as a frequent cause of chronic constipation in adults. The essential contribution of a functional histopathological technique towards a reliable diagnosis of gut dysfunction in native tissue is extensively demonstrated in great detail in more than two hundred figures. 相似文献
55.
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
56.
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
57.
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
58.
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
59.
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
60.
Rataj Elisabeth Fischer Jan Bogner Andreas Försterra Beatrice Schüssler Alexandra Schütt Lukas 《Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz》2021,64(2):179-186
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Partizipation zu ermöglichen ist Teil des Auftrags der Offenen Kinder- und Jugendarbeit. Dazu gehört die Einbindung der... 相似文献