全文获取类型
收费全文 | 2321篇 |
免费 | 123篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 60篇 |
妇产科学 | 79篇 |
基础医学 | 314篇 |
口腔科学 | 110篇 |
临床医学 | 240篇 |
内科学 | 406篇 |
皮肤病学 | 66篇 |
神经病学 | 193篇 |
特种医学 | 53篇 |
外科学 | 295篇 |
综合类 | 10篇 |
一般理论 | 1篇 |
预防医学 | 244篇 |
眼科学 | 27篇 |
药学 | 224篇 |
中国医学 | 20篇 |
肿瘤学 | 104篇 |
出版年
2023年 | 21篇 |
2022年 | 18篇 |
2021年 | 42篇 |
2020年 | 20篇 |
2019年 | 44篇 |
2018年 | 105篇 |
2017年 | 70篇 |
2016年 | 73篇 |
2015年 | 90篇 |
2014年 | 111篇 |
2013年 | 124篇 |
2012年 | 225篇 |
2011年 | 253篇 |
2010年 | 120篇 |
2009年 | 77篇 |
2008年 | 180篇 |
2007年 | 176篇 |
2006年 | 150篇 |
2005年 | 149篇 |
2004年 | 106篇 |
2003年 | 102篇 |
2002年 | 72篇 |
2001年 | 18篇 |
2000年 | 20篇 |
1999年 | 9篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 13篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1964年 | 2篇 |
1918年 | 1篇 |
1906年 | 3篇 |
1882年 | 1篇 |
排序方式: 共有2465条查询结果,搜索用时 15 毫秒
71.
Martel MJ Rey E Beauchesne MF Perreault S Forget A Maghni K Lefebvre G Blais L 《The Journal of allergy and clinical immunology》2007,119(3):576-582
BACKGROUND: The effect of inhaled short-acting beta(2)-agonists (SABAs) on pregnancy outcome, especially hypertensive complications, is not well documented. After the finding of a possible protective association of inhaled SABAs with pregnancy-induced hypertension (PIH) in a previous study, we decided to further investigate their effect on this condition. OBJECTIVE: We sought to determine the effect of inhaled SABA use during pregnancy on the risk of PIH (gestational hypertension, preeclampsia, or eclampsia) in asthmatic women. METHODS: Three of Quebec's administrative databases were linked to constitute a cohort of asthmatic women who had at least 1 delivery between 1990 and 2000. A nested case-control study was performed using up to 10 control subjects matched to each case patient for the year of conception and gestational age. Statistical analyses considered 22 confounders. RESULTS: The cohort was composed of 3505 asthmatic women who had a total of 4593 pregnancies. Three hundred two patients with PIH and 3013 control subjects were identified. Compared with nonuse, inhaled SABA use during pregnancy was significantly associated with a reduced risk of PIH (adjusted rate ratios: >0-3 doses/week, 0.62 (95% CI, 0.44-0.87); > 3-10 doses/week, 0.51 (95% CI, 0.34-0.79); and >10 doses/week, 0.48 (95% CI, 0.30-0.75)). CONCLUSIONS: To our knowledge, this is the first study reporting that inhaled SABA use during pregnancy is associated with a reduced risk of PIH. Potential explanations include pharmacologic and physiological effects or residual confounding. CLINICAL IMPLICATIONS: These results increase the evidence about the safety of inhaled SABAs in this population, although they should not undervalue the importance of maintaining good control of asthma symptoms. 相似文献
72.
73.
Marquette A Bagot M Bensussan A Dumaz N 《Archivum immunologiae et therapiae experimentalis》2007,55(6):363-372
The incidence of cutaneous malignant melanoma, tumors arising from melanocytes, has increased markedly over the past few years
in many countries. Although early melanoma is curable through surgical excision, the prognosis of advanced melanoma is very
poor, this tumor being resistant to current therapies. Thus there is a need for new therapies to improve the treatment of
advanced melanoma. This review provides an overview of recent discoveries in the genetics of melanoma which could offer new
therapeutic opportunities. 相似文献
74.
Amélie Aïm-Eusébi Emmanuel Prothon Catherine Majerholc Diana Barger Yazdan Yazdanpanah Jean-Pierre Aubert 《The European journal of general practice》2018,24(1):60-67
Background: Many people in Europe remain undiagnosed for human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV).Objectives: To evaluate acceptability and effectiveness of a questionnaire designed to facilitate identification of risk factors for these viruses.Methods: We performed an observational study, in a prospectively enrolled cohort of patients in Paris (France) seen in 2014. Eighteen GPs administered a questionnaire to the first 50 patients, collecting information about risk factors. GPs were randomized into two groups: A (self-administered questionnaire) and B (GP-administered questionnaire). We used the overall response rate to assess the acceptability of the questionnaire. We used the rate of newly identified risk factors and compared the number of tests performed one year before and immediately after the intervention to assess the effectiveness of the questionnaire.Results: 842 patients were randomized: 349 (41.5%) in group A and 493 (58.5%) in group B. Acceptability was 88.5% (95%CI: 86.3–90.6); 93.1% (95%CI: 90.5–95.8) in-group A and 85.2% (95%CI: 82.1–88.3) in group B (P?=?0.0004). Prevalence of risk factors was 51.8% (95%CI: 48.2–54.4) and 58.3% were newly identified (95%CI: 52.9–63.7). The number of HIV tests performed during the four weeks after intervention increased by 27% compared to the same period one year before (P?=?0.22). It increased by 113% (P?=?0.005) and 135% (P?=?0.005) for HBV and HCV, respectively.Conclusion: The questionnaire proved acceptable and effective in identifying risk factors for HIV, HBV and HCV in general practice. 相似文献
75.
76.
Identification of the Molecular Determinants of the Antibacterial Activity of LmutTX,a Lys49 Phospholipase A2 Homologue Isolated from Lachesis muta muta Snake Venom (Linnaeus, 1766) 下载免费PDF全文
Rafaela Diniz‐Sousa Cleópatra A. S. Caldeira Anderson M. Kayano Mauro V. Paloschi Daniel. C. Pimenta Rodrigo Simões‐Silva Amália S. Ferreira Fernando B. Zanchi Najla B. Matos Fernando P. Grabner Leonardo A. Calderon Juliana P. Zuliani Andreimar M. Soares 《Basic & clinical pharmacology & toxicology》2018,122(4):413-423
Snake venom phospholipases A2 (PLA2s) are responsible for numerous pathophysiological effects in snakebites; however, their biochemical properties favour antimicrobial actions against different pathogens, thus constituting a true source of potential microbicidal agents. This study describes the isolation of a Lys49 PLA2 homologue from Lachesis muta muta venom using two chromatographic steps: size exclusion and reverse phase. The protein showed a molecular mass of 13,889 Da and was devoid of phospholipase activity on an artificial substrate. The primary structure made it possible to identify an unpublished protein from L. m. muta venom, named LmutTX, that presented high identity with other Lys49 PLA2s from bothropic venoms. Synthetic peptides designed from LmutTX were evaluated for their cytotoxic and antimicrobial activities. LmutTX was cytotoxic against C2C12 myotubes at concentrations of at least 200 μg/mL, whereas the peptides showed a low cytolytic effect. LmutTX showed antibacterial activity against Gram‐positive and Gram‐negative bacteria; however, S. aureusATCC 29213 and MRSA strains were more sensitive to the toxin's action. Synthetic peptides were tested on S. aureus, MRSA and P. aeruginosaATCC 27853 strains, showing promising results. This study describes for the first time the isolation of a Lys49 PLA2 from Lachesis snake venom and shows that peptides from specific regions of the sequence may constitute new sources of molecules with biotechnological potential. 相似文献
77.
Débora J. Pérez Germán Lukaszewicz Mirta L. Menone María V. Amé Elsa L. Camadro 《Environmental toxicology》2014,29(9):1063-1071
Previous studies in the wetland macrophyte Bidens laevis L have demonstrated that the insecticide endosulfan induces a high frequency of somatic chromosome aberrations in anaphase–telophase (CAAT) but no DNA changes as determined by the single cell gel electrophoresis (Comet) assay. Thus, cytogenetic biomarkers appear to be more sensitive to the toxic effects of the insecticide than the DNA molecule in the studied species. For this reason, the goals of this study were to use cytogenetic biomarkers—CAAT and abnormal metaphase—and defense biomarkers such as the activity of the antioxidant enzymes—guaiacol peroxidases (POD), glutathione reductase, and microsomal and cytosolic (m‐ and c‐) glutathione‐S‐transferase (GST)—to evaluate in B. laevis effects caused by a commercial formulation of endosulfan. The frequency of CAAT was increased at 5, 10, 50, and 100 μg/L endosulfan with respect to the negative controls by 3.1, 2.5, 2.5, and 3.2‐fold, respectively while the frequency of abnormal metaphases was also increased at the same concentrations by 3.5, 2.8, 3.2, and 11.3‐fold, respectively. In addition to these aneugenic effects, other abnormalities such as C‐mitosis and chromosome clumping were observed at 10 μg/L endosulfan. On the other hand, POD induction at 0.02, 0.5, 5, and 10 μg/L and m‐GST inhibition at 0.5, 10, and 50 μg/L in plants exposed during 24 h to endosulfan were observed but all of these responses were highly variable. In conclusion, only cytogenetic biomarkers like CAAT in B. laevis can serve potentially as early warning systems to detect environmentally relevant concentrations of endosulfan in aquatic ecosystems. © 2013 Wiley Periodicals, Inc. Environ Toxicol 29: 1063–1071, 2014. 相似文献
78.
Sonia Zouaoui Amélie Darlix Pascale Fabbro-Peray Hélène Mathieu-Daudé Valérie Rigau Michel Fabbro Faiza Bessaoud Luc Taillandier François Ducray Fabienne Bauchet Michel Wager Thierry Faillot Laurent Capelle Hugues Loiseau Christine Kerr Philippe Menei Hugues Duffau Dominique Figarella-Branger Olivier Chinot Brigitte Trétarre Luc Bauchet 《Neurosurgical review》2014,37(3):415-424
The incidence of glioblastoma (GBM) has increased in patients aged 70 years or older, and will continue to grow. Elderly GBM patients have been excluded from most clinical trials; furthermore, optimal care management as well as benefit/risk ratio of GBM treatments are still being debated. This study describes oncological patterns of care, prognostic factors, and survival for patients ≥70 years in France. We identified patients over 70 with newly diagnosed and histologically confirmed GBM on data previously published by the French Brain Tumor DataBase. We included 265 patients. Neurological deficits and mental status disorders were the most frequent symptoms. The surgery consisted of resection (RS n?=?95) or biopsy (B n?=?170); 98 patients did not have subsequent oncological treatment. After surgery, first-line treatment consisted of radiotherapy (RT n?=?76), chemotherapy (CT n?=?52), and concomitant radiochemotherapy (CRC n?=?39). The median age at diagnosis was 76, 74, and 73 years, respectively, for the untreated, B?+?RT and/or CT, RS?±?RT and/or CT groups. Median survival (in days, 95 % CI) with these main strategies, when analyzed according to surgical groups, was: B-CT n?=?41, 199[155–280]; B-CRC n?=?21, 318[166–480]; B-RT n?=?37, 149[130–214]; RS-CT n?=?11, 245[211–na]; RS-CRC n?=?18, 372[349–593]; RS-RT n?=?39, 269[218–343]. This population study for elderly GBM patients is one of the most important in Europe, and could be considered as a historical cohort to compare future treatments. Moreover, we can hypothesize that elderly patients (versus patients <70 years) are undertreated. Karnofsky performance status seems to be the most relevant clinical predictive factor, and RS and CRC have a positive impact on survival for elderly GBM patients in the general population, at least when feasible. 相似文献
79.
Byung Sun Kim Junghee Lee Minji Bang Bo Am Seo Arshi Khalid Min Whan Jung Daejong Jeon 《Psychopharmacology》2014,231(22):4371-4381
Rationale
The aberrant regulation of serotonin (5-HT) and dopamine (DA) in the brain has been implicated in neuropsychiatric disorders associated with marked impairments in empathy, such as schizophrenia and autism. Many psychiatric drugs bind to both types of receptors, and the anterior cingulate cortex (ACC) is known to be centrally involved with empathy. However, the relationship between the 5-HT/DA system in the ACC and empathic behavior is not yet well known.Objectives
We investigated the role of 5-HT/DA in empathy-like behavior and in the regulation of ACC neural activity.Methods
An observational fear learning task was conducted following microinjections of 5-HT, DA, 5-HT and DA, methysergide (5-HT receptor antagonist), SCH-23390 (DA D1 receptor antagonist), or haloperidol (DA D2 receptor antagonist) into the mouse ACC. The ACC neural activity influenced by 5-HT and DA was electrophysiologically characterized in vitro and in vivo.Results
The microinjection of haloperidol, but not methysergide or SCH-23390, decreased the fear response of observing mice. The administration of 5-HT and 5-HT and DA together, but not DA alone, reduced the freezing response of observing mice. 5-HT enhanced delta-band activity and reduced alpha- and gamma-band activities in the ACC, whereas DA reduced only alpha-band activity. Based on entropy, reduced complexity of ACC neural activity was observed with 5-HT treatment.Conclusions
The current results demonstrated that DA D2 receptors in the ACC are required for observational fear learning, whereas increased 5-HT levels disrupt observational fear and alter the regularity of ACC neural oscillations. 相似文献80.
José-Francisco Rocha Amílcar Falcão Ana Santos Roberto Pinto Nelson Lopes Teresa Nunes Lyndon C. Wright Manuel Vaz-da-Silva Patrício Soares-da-Silva 《European journal of clinical pharmacology》2014,70(9):1059-1071