全文获取类型
收费全文 | 12071篇 |
免费 | 1050篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 86篇 |
儿科学 | 364篇 |
妇产科学 | 271篇 |
基础医学 | 1937篇 |
口腔科学 | 91篇 |
临床医学 | 1349篇 |
内科学 | 2633篇 |
皮肤病学 | 275篇 |
神经病学 | 1301篇 |
特种医学 | 323篇 |
外科学 | 1438篇 |
综合类 | 60篇 |
现状与发展 | 1篇 |
一般理论 | 6篇 |
预防医学 | 957篇 |
眼科学 | 224篇 |
药学 | 709篇 |
中国医学 | 12篇 |
肿瘤学 | 1135篇 |
出版年
2024年 | 16篇 |
2023年 | 149篇 |
2022年 | 222篇 |
2021年 | 542篇 |
2020年 | 342篇 |
2019年 | 519篇 |
2018年 | 497篇 |
2017年 | 388篇 |
2016年 | 399篇 |
2015年 | 434篇 |
2014年 | 591篇 |
2013年 | 684篇 |
2012年 | 1079篇 |
2011年 | 1094篇 |
2010年 | 596篇 |
2009年 | 440篇 |
2008年 | 761篇 |
2007年 | 764篇 |
2006年 | 679篇 |
2005年 | 695篇 |
2004年 | 580篇 |
2003年 | 517篇 |
2002年 | 457篇 |
2001年 | 67篇 |
2000年 | 44篇 |
1999年 | 65篇 |
1998年 | 103篇 |
1997年 | 80篇 |
1996年 | 40篇 |
1995年 | 36篇 |
1994年 | 28篇 |
1993年 | 28篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 19篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 14篇 |
1986年 | 16篇 |
1985年 | 10篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 13篇 |
1980年 | 6篇 |
1978年 | 6篇 |
1973年 | 6篇 |
1972年 | 6篇 |
1971年 | 4篇 |
1928年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
Mai-Lei Woo Kinshella Shazmeen Omar Kerri Scherbinsky Marianne Vidler Laura A. Magee Peter von Dadelszen Sophie E. Moore Rajavel Elango The PRECISE Conceptual Framework Working Group 《Nutrients》2021,13(2)
The placenta is a vital, multi-functional organ that acts as an interface between maternal and fetal circulation during pregnancy. Nutritional deficiencies during pregnancy alter placental development and function, leading to adverse pregnancy outcomes, such as pre-eclampsia, infants with small for gestational age and low birthweight, preterm birth, stillbirths and maternal mortality. Maternal nutritional supplementation may help to mitigate the risks, but the evidence base is difficult to navigate. The primary purpose of this umbrella review is to map the evidence on the effects of maternal nutritional supplements and dietary interventions on pregnancy outcomes related to placental disorders and maternal mortality. A systematic search was performed on seven electronic databases, the PROSPERO register and references lists of identified papers. The results were screened in a three-stage process based on title, abstract and full-text by two independent reviewers. Randomized controlled trial meta-analyses on the efficacy of maternal nutritional supplements or dietary interventions were included. There were 91 meta-analyses included, covering 23 types of supplements and three types of dietary interventions. We found evidence that supports supplementary vitamin D and/or calcium, omega-3, multiple micronutrients, lipid-based nutrients, and balanced protein energy in reducing the risks of adverse maternal and fetal health outcomes. However, these findings are limited by poor quality of evidence. Nutrient combinations show promise and support a paradigm shift to maternal dietary balance, rather than single micronutrient deficiencies, to improve maternal and fetal health. The review is registered at PROSPERO (CRD42020160887). 相似文献
92.
Mathilde Chataigner Marie Martin Cline Lucas Veronique Pallet Sophie Lay Alexis Mehaignerie Elodie Bouvret Anne-Laure Dinel Corinne Joffre 《Nutrients》2021,13(3)
Neuroinflammation constitutes a normal part of the brain immune response orchestrated by microglial cells. However, a sustained and uncontrolled production of proinflammatory factors together with microglial activation contribute to the onset of a chronic low-grade inflammation, leading to neuronal damage and cognitive as well as behavioral impairments. Hence, limiting brain inflammatory response and improving the resolution of inflammation could be particularly of interest to prevent these alterations. Dietary n-3 long chain polyunsaturated fatty acids (LC-PUFAs) and low molecular weight peptides are good candidates because of their immunomodulatory and proresolutive properties. These compounds are present in a fish hydrolysate derived from marine-derived byproducts. In this study, we compared the effect of an 18-day supplementation with this fish hydrolysate to a supplementation with docosahexaenoic acid (DHA) on lipopolysaccharide (LPS)-induced inflammation in mice. In response to peripherally injected LPS, the fish hydrolysate supplementation decreased the hippocampal mRNA expression of the proinflammatory cytokines IL-6 (p < 0.001), IL-1β (p = 0.0008) and TNF-α (p < 0.0001), whereas the DHA supplementation reduced only the expression of IL-6 (p = 0.004). This decline in proinflammatory cytokine expressions was associated with an increase in the protein expression of IκB (p = 0.014 and p = 0.0054 as compared to the DHA supplementation and control groups, respectively) and to a modulation of microglial activation markers in the hippocampus. The beneficial effects of the fish hydrolysate could be due in part to the switch of the hippocampal oxylipin profile towards a more anti-inflammatory profile as compared to the DHA supplementation. Thus, the valorization of fish byproducts seems very attractive to prevent and counteract neuroinflammation. 相似文献
93.
Kathryn V. Dalrymple Onome Uwhubetine Angela C. Flynn Dharmintra Pasupathy Annette L. Briley Sophie A. Relph Paul T. Seed Majella OKeeffe Lucilla Poston 《Nutrients》2021,13(6)
Pregnancy can alter a woman’s weight gain trajectory across the life course and contribute to the development of obesity through retention of weight gained during pregnancy. This study aimed to identify modifiable determinants associated with postpartum weight retention (PPWR; calculated by the difference in pre-pregnancy and 6 month postpartum weight) in 667 women with obesity from the UPBEAT study. We examined the relationship between PPWR and reported glycaemic load, energy intake, and smoking status in pregnancy, excessive gestational weight gain (GWG), mode of delivery, self-reported postpartum physical activity (low, moderate, and high), and mode of infant feeding (breast, formula, and mixed). At the 6 month visit, 48% (n = 320) of women were at or above pre-pregnancy weight. Overall, PPWR was negative (−0.06 kg (−42.0, 40.4)). Breastfeeding for ≥4 months, moderate or high levels of physical activity, and GWG ≤9 kg were associated with negative PPWR. These three determinants were combined to provide a modifiable factor score (range 0–3); for each added variable, a further reduction in PPWR of 3.0 kg (95% confidence interval 3.76, 2.25) occurred compared to women with no modifiable factors. This study identified three additive determinants of PPWR loss. These provide modifiable targets during pregnancy and the postnatal period to enable women with obesity to return to their pre-pregnancy weight. 相似文献
94.
Danielle M. Logue Laura Mahony Clare A. Corish David Tobin Ronan Doherty Grainne OHiggins Sharon M. Madigan 《Nutrients》2021,13(6)
Background: Low energy availability results in physiological adaptations which contribute to unfavourable health outcomes. Little information exists on perceptions of nutritional advice to eat more food to maintain health and enhance performance. The aim of this study was to explore athletes’ and coaches’ perceptions towards advice to athletes to eat larger than their current quantities of food and to explore how nutritionists could deliver this advice. Methods: Semi-structured interviews (~20 min in length) were conducted using online communication technology, audio-recorded, and transcribed verbatim. The interview explored perceptions of the nutritional advice provided, its role in health and performance, and the challenges to eating larger amounts of food. Data were analysed using NVIVO 1.2 using an inductive thematic approach. Results: Nine elite athletes (female = 6; males = 3) and nine high-performance coaches (female = 3; male = 6) completed the semi-structured interviews. Athletes reported improved training consistency, fewer injuries and illnesses, and improved resilience when consuming adequate energy and nutrients to meet their needs. Lack of time and meal preparation difficulties were the main challenges faced to fuelling. Conclusions: Although education about under-fuelling is important, motivating, enabling, and supporting athletes to change behaviour is pivotal to increasing athlete self-awareness and to make long-term nutritional changes. 相似文献
95.
96.
97.
Tony Wawina-Bokalanga Bert Vanmechelen Valentine Lhermitte Joan Martí-Carreras Valentijn Vergote Fara Raymond Koundouno Joseph Akoi-Bor Ruth Thom Tom Tipton Kimberley Steeds Kita Balla Moussa Ablam Amento Lies Laenen Sophie Duraffour Martin Gabriel Paula Ruibal Yper Hall Mandy Kader-Kond Stephan Günther Guy Baele Cesar Muoz-Fontela Johan Van Weyenbergh Miles W. Carroll Piet Maes 《Emerging infectious diseases》2021,27(1):76
We investigated the genetic profiles of killer cell immunoglobulin-like receptors (KIRs) in Ebola virus–infected patients. We studied the relationship between KIR–human leukocyte antigen (HLA) combinations and the clinical outcomes of patients with Ebola virus disease (EVD). We genotyped KIRs and HLA class I alleles using DNA from uninfected controls, EVD survivors, and persons who died of EVD. The activating 2DS4–003 and inhibitory 2DL5 genes were significantly more common among persons who died of EVD; 2DL2 was more common among survivors. We used logistic regression analysis and Bayesian modeling to identify 2DL2, 2DL5, 2DS4–003, HLA-B-Bw4-Thr, and HLA-B-Bw4-Ile as probably having a significant relationship with disease outcome. Our findings highlight the importance of innate immune response against Ebola virus and show the association between KIRs and the clinical outcome of EVD. 相似文献
98.
Franois-Xavier Briand Eric Niqueux Audrey Schmitz Claire Martenot Martine Cherbonnel Pascale Massin Florian Kerbrat Marina Chatel Carole Guillemoto Cecile Guillou-Cloarec Katell Ogor Aurlie Le Prioux Chantal Alle Vronique Beven Edouard Hirchaud Yannick Blanchard Axelle Scoizec Sophie Le Bouquin Nicolas Eterradossi Batrice Grasland 《Emerging infectious diseases》2021,27(2):508
We detected 3 genotypes of highly pathogenic avian influenza A(H5N8) virus in France during winter 2016–17. Genotype A viruses caused dramatic economic losses in the domestic duck farm industry in southwestern France. Our phylogenetic analysis suggests that genotype A viruses formed 5 distinct geographic clusters in southwestern France. In some clusters, local secondary transmission might have been started by a single introduction. The intensity of the viral spread seems to correspond to the density of duck holdings in each production area. To avoid the introduction of disease into an unaffected area, it is crucial that authorities limit the movements of potentially infected birds. 相似文献
99.
Ria R. Ghai Ann Carpenter Amanda Y. Liew Krystalyn B. Martin Meghan K. Herring Susan I. Gerber Aron J. Hall Jonathan M. Sleeman Sophie VonDobschuetz Casey Barton Behravesh 《Emerging infectious diseases》2021,27(4):1015
The ongoing global pandemic caused by coronavirus disease has once again demonstrated the role of the family Coronaviridae in causing human disease outbreaks. Because severe acute respiratory syndrome coronavirus 2 was first detected in December 2019, information on its tropism, host range, and clinical manifestations in animals is limited. Given the limited information, data from other coronaviruses might be useful for informing scientific inquiry, risk assessment, and decision-making. We reviewed endemic and emerging infections of alphacoronaviruses and betacoronaviruses in wildlife, livestock, and companion animals and provide information on the receptor use, known hosts, and clinical signs associated with each host for 15 coronaviruses detected in humans and animals. This information can be used to guide implementation of a One Health approach that involves human health, animal health, environmental, and other relevant partners in developing strategies for preparedness, response, and control to current and future coronavirus disease threats. 相似文献
100.
Marysol Luna Jason D Guss Laura S Vasquez-Bolanos Macy Castaneda Manuela Vargas Rojas Jasmin M Strong Denise A Alabi Sophie D Dornevil Jacob C Nixon Erik A Taylor Eve Donnelly Xueyan Fu M Kyla Shea Sarah L Booth Rodrigo Bicalho Christopher J Hernandez 《Journal of bone and mineral research》2021,36(9):1823-1834
Modifications to the constituents of the gut microbiome influence bone density and tissue-level strength, but the specific microbial components that influence tissue-level strength in bone are not known. Here, we selectively modify constituents of the gut microbiota using narrow-spectrum antibiotics to identify components of the microbiome associated with changes in bone mechanical and material properties. Male C57BL/6J mice (4 weeks) were divided into seven groups (n = 7–10/group) and had taxa within the gut microbiome removed through dosing with: (i) ampicillin; (ii) neomycin; (iii) vancomycin; (iv) metronidazole; (v) a cocktail of all four antibiotics together (with zero-calorie sweetener to ensure intake); (vi) zero-calorie sweetener only; or (vii) no additive (untreated) for 12 weeks. Individual antibiotics remove only some taxa from the gut, while the cocktail of all four removes almost all microbes. After accounting for differences in geometry, whole bone strength was reduced in animals with gut microbiome modified by neomycin (−28%, p = 0.002) and was increased in the group in which the gut microbiome was altered by sweetener alone (+39%, p < 0.001). Analysis of the fecal microbiota detected seven lower-ranked taxa differentially abundant in animals with impaired tissue-level strength and 14 differentially abundant taxa associated with increased tissue-level strength. Histological and serum markers of bone turnover and trabecular bone volume per tissue volume (BV/TV) did not differ among groups. These findings demonstrate that modifications to the taxonomic components of the gut microbiome have the potential to decrease or increase tissue-level strength of bone independent of bone quantity and without noticeable changes in bone turnover. © 2021 American Society for Bone and Mineral Research (ASBMR). 相似文献