全文获取类型
收费全文 | 16023篇 |
免费 | 1071篇 |
国内免费 | 74篇 |
专业分类
耳鼻咽喉 | 186篇 |
儿科学 | 444篇 |
妇产科学 | 333篇 |
基础医学 | 2199篇 |
口腔科学 | 377篇 |
临床医学 | 1402篇 |
内科学 | 3705篇 |
皮肤病学 | 615篇 |
神经病学 | 1529篇 |
特种医学 | 375篇 |
外科学 | 1583篇 |
综合类 | 73篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 1835篇 |
眼科学 | 318篇 |
药学 | 1043篇 |
中国医学 | 65篇 |
肿瘤学 | 1081篇 |
出版年
2024年 | 16篇 |
2023年 | 208篇 |
2022年 | 365篇 |
2021年 | 840篇 |
2020年 | 397篇 |
2019年 | 779篇 |
2018年 | 971篇 |
2017年 | 541篇 |
2016年 | 520篇 |
2015年 | 594篇 |
2014年 | 797篇 |
2013年 | 1102篇 |
2012年 | 1517篇 |
2011年 | 1502篇 |
2010年 | 939篇 |
2009年 | 685篇 |
2008年 | 812篇 |
2007年 | 757篇 |
2006年 | 680篇 |
2005年 | 680篇 |
2004年 | 571篇 |
2003年 | 525篇 |
2002年 | 473篇 |
2001年 | 95篇 |
2000年 | 43篇 |
1999年 | 94篇 |
1998年 | 95篇 |
1997年 | 83篇 |
1996年 | 76篇 |
1995年 | 52篇 |
1994年 | 29篇 |
1993年 | 41篇 |
1992年 | 28篇 |
1991年 | 22篇 |
1990年 | 17篇 |
1989年 | 8篇 |
1988年 | 13篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 8篇 |
1984年 | 18篇 |
1983年 | 15篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1974年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Rosario G. Merodio-Perea Isabel Lado-Tourio Alicia Pez-Pavn Carlos Talayero Andrea Galn-Salazar Omar Aït-Salem 《Materials》2022,15(21)
Concrete is well known for its compression resistance, making it suitable for any kind of construction. Several research studies show that the addition of carbon nanostructures to concrete allows for construction materials with both a higher resistance and durability, while having less porosity. Among the mentioned nanostructures are carbon nanotubes (CNTs), which consist of long cylindrical molecules with a nanoscale diameter. In this work, molecular dynamics (MD) simulations have been carried out, to study the effect of pristine or carboxyl functionalized CNTs inserted into a tobermorite crystal on the mechanical properties (elastic modulus and interfacial shear strength) of the resulting composites. The results show that the addition of the nanostructure to the tobermorite crystal increases the elastic modulus and the interfacial shear strength, observing a positive relation between the mechanical properties and the atomic interactions established between the tobermorite crystal and the CNT surface. In addition, functionalized CNTs present enhanced mechanical properties. 相似文献
132.
133.
Patrícia Lipari Pinto Cristina Florindo Patrícia Janeiro Rita Loureiro Santos Sandra Mexia Hugo Rocha Isabel Tavares de Almeida Laura Vilarinho Ana Gaspar 《Nutrients》2022,14(20)
The early diagnosis of and intervention in vitamin B12 deficiency in exclusively breastfed infants by mothers with low vitamin B12 is crucial in preventing possible irreversible neurologic damage, megaloblastic anemia, and failure to thrive. We assess the usefulness of the early detection of asymptomatic B12 deficiency related to acquired conditions and highlight the importance of monitoring serum vitamin B12 levels during pregnancy. We describe demographic, clinical, dietary, and biochemical data, including the evolution of a vitamin B12 deficiency’s functional biomarkers. We enrolled 12 newborns (5 males) with an age range of 1–2 months old that were exclusively breastfed and asymptomatic. These cases were referred to our metabolic unit due to alterations in expanded newborn screening: high levels of methylmalonic acid and/or total homocysteine (tHcy). All mothers were under a vegetarian diet except three who had abnormal B12 absorption, and all presented low or borderline serum B12 level and high plasma levels of tHcy. Supplementation with oral vitB12 re-established the metabolic homeostasis of the mothers. In infants, therapy with an intramuscular injection of 1.0 mg hydroxocobalamin led to the rapid normalization of the metabolic pattern, and a healthy outcome was observed. Acquired B12 deficiency should be ruled out before proceeding in a differential diagnosis of cobalamin metabolism deficits, methylmalonic acidemia, and homocystinuria. 相似文献
134.
135.
Matthew R. Lewin Rebecca W. Carter Isabel A. Matteo Stephen P. Samuel Sunita Rao Bryan G. Fry Philip E. Bickler 《Toxins》2022,14(11)
The availability of effective, reliably accessible, and affordable treatments for snakebite envenoming is a critical and long unmet medical need. Recently, small, synthetic toxin-specific inhibitors with oral bioavailability used in conjunction with antivenom have been identified as having the potential to greatly improve outcomes after snakebite. Varespladib, a small, synthetic molecule that broadly and potently inhibits secreted phospholipase A2 (sPLA2s) venom toxins has renewed interest in this class of inhibitors due to its potential utility in the treatment of snakebite envenoming. The development of varespladib and its oral dosage form, varespladib-methyl, has been accelerated by previous clinical development campaigns to treat non-envenoming conditions related to ulcerative colitis, rheumatoid arthritis, asthma, sepsis, and acute coronary syndrome. To date, twenty-nine clinical studies evaluating the safety, pharmacokinetics (PK), and efficacy of varespladib for non-snakebite envenoming conditions have been completed in more than 4600 human subjects, and the drugs were generally well-tolerated and considered safe for use in humans. Since 2016, more than 30 publications describing the structure, function, and efficacy of varespladib have directly addressed its potential for the treatment of snakebite. This review summarizes preclinical findings and outlines the scientific support, the potential limitations, and the next steps in the development of varespladib’s use as a snakebite treatment, which is now in Phase 2 human clinical trials in the United States and India. 相似文献
136.
Patricio A. Díaz Carlos Molinet Miriam Seguel Edwin J. Niklitschek Manuel Díaz Gonzalo lvarez Ivn Prez-Santos Daniel Varela Leonardo Guzmn Camilo Rodríguez-Villegas Rosa I. Figueroa 《Toxins》2022,14(11)
Harmful algal blooms, in particular recurrent blooms of the dinoflagellate Alexandrium catenella, associated with paralytic shellfish poisoning (PSP), frequently limit commercial shellfish harvests, resulting in serious socio-economic consequences. Although the PSP-inducing species that threaten the most vulnerable commercial species of shellfish are very patchy and spatially heterogeneous in their distribution, the spatial and temporal scales of their effects have largely been ignored in monitoring programs and by researchers. In this study, we examined the spatial and temporal dynamics of PSP toxicity in the clam (Ameghinomya antiqua) in two fishing grounds in southern Chile (Ovalada Island and Low Bay). During the summer of 2009, both were affected by an intense toxic bloom of A. catenella (up to 1.1 × 106 cells L−1). Generalized linear models were used to assess the potential influence of different environmental variables on the field detoxification rates of PSP toxins over a period of 12 months. This was achieved using a four parameter exponential decay model to fit and compare field detoxification rates per sampling site. The results show differences in the spatial variability and temporal dynamics of PSP toxicity, given that greater toxicities (+10-fold) and faster detoxification (20% faster) are observed at the Ovalada Island site, the less oceanic zone, and where higher amounts of clam are annually produced. Our observations support the relevance of considering different spatial and temporal scales to obtain more accurate assessments of PSP accumulation and detoxification dynamics and to improve the efficacy of fisheries management after toxic events. 相似文献
137.
Cristina Dopazo Itxarone Bilbao Sonia García Concepcin GmezGavara Mireia Caralt Isabel CamposVarela Lluis Castells Ernest Hidalgo Francisco Moreso Bruno Montoro Ramn Charco 《CTS Clinical and Translational Science》2022,15(6):1544
Tacrolimus (TAC) is a dose‐dependent immunosuppressor with considerable intrapatient variability (IPV) in its pharmacokinetics. The aim of this work is to ascertain the association between TAC IPV at 6 months after liver transplantation (LT) and patient outcome. This single‐center cohort study retrospectively analyzed adult patients who underwent transplantation from 2015 to 2019 who survived the first 6 months with a functioning graft. The primary end point was the patient’s probability of death and the secondary outcome was the loss of renal function between month 6 and the last follow‐up. TAC IPV was estimated by calculating the coefficient of variation (CV) of the dose‐corrected concentration (C0/D) between the third and sixth months post‐LT. Of the 140 patients who underwent LT included in the study, the low‐variability group (C0/D CV < 27%) comprised 105 patients and the high‐variability group (C0/D CV ≥ 27%) 35 patients. One‐, 3‐, and 5‐year patient survival rates were 100%, 82%, and 72% in the high‐variability group versus 100%, 97%, and 93% in the low‐variability group, respectively (p = 0.005). Moreover, significant impaired renal function was observed in the high‐variability group at 1 year (69 ± 16 ml/min/1.73 m2 vs. 78 ± 16 ml/min/1.73 m2, p = 0.004) and at 2 years post‐LT (69 ± 17 ml/min/1.73 m2 vs. 77 ± 15 ml/min/1.73 m2, p = 0.03). High C0/D CV 3–6 months remained independently associated with worse survival (hazard ratio = 3.57, 95% CI = 1.32–9.67, p = 0.012) and loss of renal function (odds ratio = 3.47, 95% CI = 1.30–9.20, p = 0.01). Therefore, high IPV between the third and sixth months appears to be an early and independent predictor of patients with poorer liver transplant outcomes.
Abbreviations
- BPAR
- Biopsy proven acute rejection
- BMI
- Body mass index
- CKD‐EPI
- chronic kidney disease epidemiology collaboration
- CV
- coefficient of variation
- C0/D
- dose‐corrected concentration
- CMV
- cytomegalovirus
- eGFR
- estimated glomerular filtration rate
- HR
- hazard ratio
- HCC
- hepatocellular carcinoma
- ICU
- intensive care unit
- IPV
- intrapatient variability
- i.v.
- intravenously
- LC–MS/MS
- liquid chromatography‐ tandem mass spectrometry
- LT
- liver transplantation
- MELD
- model for end‐stage liver disease
- MMF
- mycophenolate mofetil
- NASH
- Non‐Alcoholic Steatohepatitis
- OR
- odds ratio
- PCR
- polymerase chain reaction
- SD
- Standard Deviation
- TAC
- tacrolimus
- 3–6 M
- three–six months
- WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?
- WHAT QUESTION DID THIS STUDY ADDRESS?
- WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?
- HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?
138.
Li F Maskey RP Qin S Sattler I Fiebig HH Maier A Zeeck A Laatsch H 《Journal of natural products》2005,68(3):349-353
In our screening of marine Streptomycetes for bioactive principles, two novel antitumor antibiotics designated as chinikomycins A (2a) and B (2b) were isolated together with manumycin A (1), and their structures were elucidated by a detailed interpretation of their spectra. Chinikomycins A (2a) and B (2b) are chlorine-containing aromatized manumycin derivatives of the type 64-pABA-2 with an unusual para orientation of the side chains. They exhibited antitumor activity against different human cancer cell lines, but were inactive in antiviral, antimicrobial, and phytotoxicity tests. 相似文献
139.
Birth outcomes of patients with isolated anorectal malformations: A population‐based case‐control study 下载免费PDF全文
In most patients affected by isolated anorectal malformation (IARM) the etiology is largely unknown. Thus, the aim of our project was to analyze possible risk factors for IARM. In the first step, birth outcomes of cases with IARM were analyzed on the basis of maternal socio‐demographic variables, and these data are presented in this paper. Gestational age at delivery, birthweight, preterm birth, low birthweight and small for gestational age of cases with IARM were evaluated in the function of maternal age, birth/pregnancy order, marital and employment status of mothers in the population‐based large dataset of the Hungarian Case‐Control Surveillance of Congenital Abnormalities, 1980–1996. The study samples included 231 live‐born cases with IARM, 361 matched and 38 151 population controls without any defect. IARMs are more frequent in males, twins and newborn infants with low birthweight and small‐for‐gestational‐age, the latter being the consequence of intrauterine growth restriction. In addition, mothers of cases were younger but with higher birth order, and had lower socio‐economic status. These maternal variables are characteristic for the gypsy population in Hungary. The higher proportion of gypsy women among the mothers of cases with IARM was confirmed during the home visits of the study. Male sex and intrauterine growth restriction of cases, in addition to low socioeconomic status and gypsy origin of mothers may have a role in the risk of IARMs. 相似文献
140.