全文获取类型
收费全文 | 9011篇 |
免费 | 618篇 |
国内免费 | 64篇 |
专业分类
耳鼻咽喉 | 62篇 |
儿科学 | 215篇 |
妇产科学 | 192篇 |
基础医学 | 1572篇 |
口腔科学 | 121篇 |
临床医学 | 887篇 |
内科学 | 2302篇 |
皮肤病学 | 125篇 |
神经病学 | 808篇 |
特种医学 | 177篇 |
外科学 | 706篇 |
综合类 | 41篇 |
一般理论 | 1篇 |
预防医学 | 793篇 |
眼科学 | 131篇 |
药学 | 768篇 |
中国医学 | 28篇 |
肿瘤学 | 764篇 |
出版年
2024年 | 11篇 |
2023年 | 117篇 |
2022年 | 263篇 |
2021年 | 401篇 |
2020年 | 208篇 |
2019年 | 277篇 |
2018年 | 324篇 |
2017年 | 235篇 |
2016年 | 227篇 |
2015年 | 320篇 |
2014年 | 357篇 |
2013年 | 506篇 |
2012年 | 718篇 |
2011年 | 723篇 |
2010年 | 391篇 |
2009年 | 368篇 |
2008年 | 613篇 |
2007年 | 654篇 |
2006年 | 584篇 |
2005年 | 534篇 |
2004年 | 437篇 |
2003年 | 436篇 |
2002年 | 392篇 |
2001年 | 23篇 |
2000年 | 38篇 |
1999年 | 49篇 |
1998年 | 72篇 |
1997年 | 52篇 |
1996年 | 35篇 |
1995年 | 23篇 |
1994年 | 11篇 |
1993年 | 16篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1989年 | 8篇 |
1988年 | 9篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 16篇 |
1984年 | 11篇 |
1982年 | 7篇 |
1981年 | 22篇 |
1980年 | 10篇 |
1978年 | 12篇 |
1977年 | 13篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1974年 | 7篇 |
1972年 | 7篇 |
1966年 | 6篇 |
排序方式: 共有9693条查询结果,搜索用时 15 毫秒
61.
Origin and primary dispersal of the Mycobacterium tuberculosis Beijing genotype: clues from human phylogeography 总被引:2,自引:0,他引:2 下载免费PDF全文
Mokrousov I Ly HM Otten T Lan NN Vyshnevskyi B Hoffner S Narvskaya O 《Genome research》2005,15(10):1357-1364
We suggest that the evolution of the population structure of microbial pathogens is influenced by that of modern humans. Consequently, the timing of hallmark changes in bacterial genomes within the last 100,000 yr may be attempted by comparison with relevant human migrations. Here, we used a lineage within Mycobacterium tuberculosis, a Beijing genotype, as a model and compared its phylogeography with human demography and Y chromosome-based phylogeography. We hypothesize that two key events shaped the early history of the Beijing genotype: (1) its Upper Palaeolithic origin in the Homo sapiens sapiens K-M9 cluster in Central Asia, and (2) primary Neolithic dispersal of the secondary Beijing NTF::IS6110 lineage by Proto-Sino-Tibetan farmers within east Asia (human O-M214/M122 haplogroup). The independent introductions of the Beijing strains from east Asia to northern Eurasia and South Africa were likely historically recent, whereas their differential dissemination within these areas has been influenced by demographic and climatic factors. 相似文献
62.
Deniz Eyice Karabacak Semra Demir Osman Ozan Yeğit Ali Can Kadriye Terzioğlu Derya Ünal Müge Olgaç Raif Coşkun Bahauddin Çolakoğlu Suna Büyüköztürk Aslı Gelincik 《Allergy》2021,76(8):2535-2543
Background
Hereditary angioedema (HAE) attacks can be provoked with psychological factors. The aim of this study was to assess the effects of anxiety, depression and stress related to COVID-19 pandemic on disease activity of HAE patients during the quarantine period (QP) and the return to normal period (RTNP).Methods
This study was conducted between March 2020 and September 2020 in four allergy centres. Demographic, clinical features and mental health status were evaluated in QP (from March to the beginning of June) and RTNP (from June to the beginning of September) applied by the government. The 10-point visual analogue scale (VAS10) was used to define the severity of HAE attacks. Depression, Anxiety and Stress Scales-21 (DASS-21) and Fear of COVID-19 (FC-19) scale were performed to assess mental health status.Results
139 HAE patients were included in the study. In QP, median attack numbers and median VAS10 scores were 5 (min-max: 0–45) and 6 (min-max: 0–10), respectively. HAE attack numbers, DASS-21 stress, anxiety, depression and total DASS-21 scores, and FC-19 scores were higher in QP than RTNP (p = 0.001, p < 0.001, p = 0.001, p < 0.001, p < 0.001, p < 0.001, respectively). However, there was no difference in attack severity scores between the two periods (p > 0.05).Conclusions
This study revealed that the restriction measures during COVID-19 outbreak cause an increase in the number of HAE attacks in relation to anxiety, depression, stress and fear of COVID-19 pandemic. Therefore, it is important to provide psychological support to HAE patients during the pandemic.63.
Alexander Yu. Bilibin Olga S. Sokolova Anatoly J. Grigorjev 《Macromolecular chemistry and physics.》1996,197(3):1021-1029
Two series of fluorine-containing liquid crystalline polyesters were synthesized from fluorinated alkylene diols and mesogenic acid dichlorides. The thermal behaviour of the polymers differs considerably from that of their hydrocarbon analogues. Formation of a nematic phase was observed only for melts of polymers with fluorinated spacers whereas polymers with alkylene spacers form mainly smectic phases. The most interesting feature is the unusual dependence of the polymer melting temperature on the spacer length — it increases with increasing number of CF2 groups in the spacer. 相似文献
64.
Smooth muscle myosin filament assembly under control of a kinase-related protein (KRP) and caldesmon
Kudryashov DS Vorotnikov AV Dudnakova TV Stepanova OV Lukas TJ Sellers JR Watterson DM Shirinsky VP 《Journal of muscle research and cell motility》2002,23(4):341-351
Kinase-related protein (KRP) and caldesmon are abundant myosin-binding proteins of smooth muscle. KRP induces the assembly
of unphosphorylated smooth muscle myosin filaments in the presence of ATP by promoting the unfolded state of myosin. Based
upon electron microscopy data, it was suggested that caldesmon also possessed a KRP-like activity (Katayama et al., 1995, J Biol Chem 270: 3919–3925). However, the nature of its activity remains obscure since caldesmon does not affect the equilibrium between
the folded and unfolded state of myosin. Therefore, to gain some insight into this problem we compared the effects of KRP
and caldesmon, separately, and together on myosin filaments using turbidity measurements, protein sedimentation and electron
microscopy. Turbidity assays demonstrated that KRP reduced myosin filament aggregation, while caldesmon had no effect. Additionally,
neither caldesmon nor its N-terminal myosin binding domain (N152) induced myosin polymerization at subthreshold Mg2+ concentrations in the presence of ATP, whereas the filament promoting action of KRP was enhanced by Mg2+. Moreover, the amino-terminal myosin binding fragment of caldesmon, like the whole protein, antagonizes Mg2+-induced myosin filament formation. In electron microscopy experiments, caldesmon shortened myosin filaments in the presence
of Mg2+ and KRP, but N152 failed to change their appearance from control. Therefore, the primary distinction between caldesmon and
KRP appears to be that caldesmon interacts with myosin to limit filament extension, while KRP induces filament propagation
into defined polymers. Transfection of tagged-KRP into fibroblasts and overlay of fibroblast cytoskeletons with Cy3KRP demonstrated
that KRP colocalizes with myosin structures in vivo. We propose a new model that through their independent binding to myosin and differential effects on myosin dynamics, caldesmon
and KRP can, in concert, control the length and polymerization state of myosin filaments.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
65.
Francesca Snchez-Martínez Silvia Brugueras Gemma Serral Sara Valmayor Olga Jurez María Jos Lpez Carles Ariza 《Nutrients》2021,13(2)
Childhood obesity has increased worldwide over the past four decades. This quasi-experimental study aimed to assess the effectiveness of a multicomponent and multilevel school-based intervention (POIBA) at 3 years of follow-up. The nutrition intervention focused on food groups, food pyramid, nutrients, portions, and balanced menus. In total, 3624 children participated in the study. Anthropometric measurements and information on food frequency and behavior, physical activity, and daily screen use were collected in the intervention (IG) and comparison group (CG). Positive unadjusted changes toward adherence to recommendations were found for water, meat, sweets, and fried potato consumption, proper breakfast, not having dinner in front of the TV, out-of-school physical activity, and daily screen use. Three scores were used to calculate the proportion of children making more than one change to improve healthy habits regarding physical activity (global Activity score), nutrition (global Nutrition score), and both (global score). Students exposed to the intervention had a significantly better global Activity score (16.2% IG vs. 11.9% CG; p = 0.012) and Global score (63.9% IG vs. 58.5% CG; p = 0.025). Intervention effects on obesity incidence at 3-year follow-up lost significance but maintained the positive trend. In conclusion, school-based interventions including a family component could be useful to address the childhood obesity problem. 相似文献
66.
Dragana Arsenijevic Bojana Stojanovic Jelena Milovanovic Aleksandar Arsenijevic Milos Simic Marija Pergal Igor Kodranov Olga Cvetkovic Danilo Vojvodic Elizabeta Ristanovic Dragan Manojlovic Marija Milovanovic Nebojsa Arsenijevic 《Nutrients》2021,13(3)
The main biologically active components of plants belonging to the genus Allium, responsible for their biological activities, including anti-inflammatory, antioxidant and immunomodulatory, are organosulfur compounds. The aim of this study was to synthetize the mixture of dipropyl polysulfides (DPPS) and to test their biological activity in acute hepatitis. C57BL/6 mice were administered orally with DPPS 6 h before intravenous injection of Concanavalin A (ConA). Liver inflammation, necrosis and hepatocytes apoptosis were determined by histological analyses. Cytokines in liver tissue were determined by ELISA, expression of adhesive molecules and enzymes by RT PCR, while liver mononuclear cells were analyzed by flow cytometry. DPPS pretreatment significantly attenuated liver inflammation and injury, as evidenced by biochemical and histopathological observations. In DPPS-pretreated mice, messenger RNA levels of adhesion molecules and NADPH oxidase complex were significantly reduced, while the expression of SOD enzymes was enhanced. DPPS pretreatment decreased protein level of inflammatory cytokines and increased percentage of T regulatory cells in the livers of ConA mice. DPPS showed hepatoprotective effects in ConA-induced hepatitis, characterized by attenuation of inflammation and affection of Th17/Treg balance in favor of T regulatory cells and implicating potential therapeutic usage of DPPS mixture in inflammatory liver diseases. 相似文献
67.
A diet rich in nutrients should be implemented in order to boost the immune system and prevent infections. To investigate which nutrients are commonly consumed, an anonymous survey was given to 120 individuals and their responses were collected. The respondents answered questions relating to their health status, and their consumption of nutrients and supplements that produce immunomodulating effects. The participants were also asked about any prior viral, bacterial or fungal infections experienced, and in particular, infection frequency, course, and duration. The data collected were subjected to a statistical analyses to assess the relationship between the reported frequency of infections and nutrients consumed including vitamins D3, A, C, E, selenium, zinc, iron, β-carotene, omega-3 fatty acids as well as live active probiotic bacteria. The findings show that vitamin and mineral supplementation did not positively affect the duration, frequency, or course of infections in the surveyed sample. An exception was vitamin D3 supplementation that was correlated to sporadic incidence of viral infections. Conversely, immunity was positively affected by consumption of natural nutrients contained in whole food (vitamin C, iron, selenium, omega-3 fatty acids), evidenced by lower incidences and milder courses of infection. 相似文献
68.
Jos J. Mira Martín Blanco Kamila CheikhMoussa Olga Solas Aquilino Alonso Rodrigo Gutierrez Celia Gmez Mercedes Guilabert 《Health expectations》2021,24(2):687
BackgroundIn this COVID‐19 era, we need to rethink the criteria used to measure the results of person‐centred care strategies.ObjectiveTo identify priorities, and criteria that health services can use to pursue actually the goal of achieving person‐centred care.DesignThree‐phase online qualitative study performed during May–July of 2020 using the Delphi technique.Setting and ParticipantsAn online platform was used for a consensus meeting of 114 participants, including health planning experts, health‐care institution managers, clinicians and patients.Main Outcome MeasuresCriteria and indicators for the achievement of person‐centred care.Main ResultsThe first round began with 125 proposals and 11 dimensions. After the second round, 28 ideas reached a high level of consensus among the participants. Ultimately, the workgroup agreed on 20 criteria for goals in the implementation of person‐centred care during the COVID‐19 era and 21 related indicators to measure goal achievement.DiscussionNine dimensions and 28 priorities were identified. These priorities are also in accordance with the quadruple aim approach, which emphasizes the need for care for health‐care professionals, without whom it is impossible to achieve a better quality of care.ConclusionsPerson‐centred care continues to be a key objective. However, new metrics are needed to ensure its continued development during the restoration of public health services beyond the control of COVID‐19.Patient or Public ContributionTwelve professionals and patient representatives participated voluntarily in the construction of the baseline questionnaire and in the selection of the criteria and indicators using an online platform for consensus meetings. 相似文献
69.
Adva Aizer Olga Dratviman-Storobinsky Meirav Noach-Hirsh Sarah Konopnicki Alon Lazarovich Gil Raviv Raoul Orvieto 《Andrologia》2021,53(1):e13849
We sought to compare ICSI outcomes of cycle using fresh versus thawed TESE spermatozoa obtained during the previous fresh TESE. All consecutive couples undergoing ICSI cycles using fresh TESE spermatozoa, followed by ICSI cycle using cryopreserved sperm remaining from the previous fresh TESE procedure were included. Ovarian stimulation (OS)/laboratory variables and cycle outcome were assessed and compared between those utilising fresh versus thawed TESE spermatozoa. Seventy-five couples were evaluated, with no in-between groups differences in OS nor embryological variables. While implantation and LBR per embryo transfer were nonsignificantly higher in the frozen as compared to the fresh TESE, there was a trend towards higher LBRs per patient in the frozen TESE group. The cumulative miscarriage rate (4% versus 14.7%, p < .022 respectively) was significantly lower and the cumulative LBR (34.7% versus 16%, p < .007 respectively) was significantly higher using frozen TESE spermatozoa. Moreover, significantly higher proportion of frozen TESE sperm samples used pentoxifylline to enhance sperm motility. In conclusion, the results of ICSI cycles using frozen TESE spermatozoa are as good, or even better than using fresh TESE spermatozoa. Further studies are required to explore the factors responsible for the improved ICSI outcome, while using frozen versus fresh TESE sperm samples. 相似文献
70.
ObjectivesThe COVID-19 pandemic has significantly impacted the healthcare systems. Many Polish outpatient clinics have been implementing telemedical consultations as a tool to ensure the continuity of care for patients with chronic diseases. The aim of the study was to evaluate patients’ satisfaction with telemedical appointments, as well as availability of the various medical services and patients’ well-being during the pandemic.Material and methodsAn online-based questionnaire on the experience with telemedical consultations, availability of medical services and current state of health was conducted among Polish rheumatology patients approximately 6 months after the outbreak of the COVID-19 pandemic.ResultsThe survey was completed by 107 respondents with a mean age of 41.52 ±14.33 years. The overall level of satisfaction from telemedical consultations, evaluated with a VAS 1–10 scale, was assessed as 6.23 ±3.04 for teleconsultations in primary healthcare units and 6.00 ±2.80 for rheumatology outpatient units. 42.99% of the respondents were in favour of maintaining telemedical appointments even after the pandemic. Incidences of reduced access to medical services during the COVID-19 pandemic were reported by 77.57% of the patients. Almost half of the respondents reported reduced accessibility to rheumatological care. An alarming decline in health self-esteem, evaluated with a VAS 1–10 scale, was noted from the average 6.37 ±1.92 before COVID-19 to the current rating of 5.78 ±1.91 (p = 0.0087).ConclusionsPolish rheumatology patients are moderately satisfied with the medical teleconsultations in primary health care units and rheumatology outpatient clinics. A substantial number of patients experienced deterioration of well-being as well as limited access to traditional healthcare services, including rheumatology care. 相似文献