全文获取类型
收费全文 | 10319篇 |
免费 | 757篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 78篇 |
儿科学 | 293篇 |
妇产科学 | 293篇 |
基础医学 | 1389篇 |
口腔科学 | 233篇 |
临床医学 | 1308篇 |
内科学 | 2041篇 |
皮肤病学 | 259篇 |
神经病学 | 1089篇 |
特种医学 | 202篇 |
外科学 | 903篇 |
综合类 | 64篇 |
一般理论 | 16篇 |
预防医学 | 1311篇 |
眼科学 | 181篇 |
药学 | 683篇 |
中国医学 | 32篇 |
肿瘤学 | 738篇 |
出版年
2024年 | 16篇 |
2023年 | 133篇 |
2022年 | 225篇 |
2021年 | 467篇 |
2020年 | 263篇 |
2019年 | 361篇 |
2018年 | 383篇 |
2017年 | 275篇 |
2016年 | 316篇 |
2015年 | 319篇 |
2014年 | 395篇 |
2013年 | 586篇 |
2012年 | 833篇 |
2011年 | 827篇 |
2010年 | 478篇 |
2009年 | 376篇 |
2008年 | 639篇 |
2007年 | 623篇 |
2006年 | 575篇 |
2005年 | 545篇 |
2004年 | 461篇 |
2003年 | 438篇 |
2002年 | 393篇 |
2001年 | 43篇 |
2000年 | 35篇 |
1999年 | 41篇 |
1998年 | 68篇 |
1997年 | 68篇 |
1996年 | 60篇 |
1995年 | 51篇 |
1994年 | 40篇 |
1993年 | 45篇 |
1992年 | 32篇 |
1991年 | 31篇 |
1990年 | 26篇 |
1989年 | 24篇 |
1988年 | 27篇 |
1987年 | 28篇 |
1986年 | 25篇 |
1985年 | 26篇 |
1984年 | 33篇 |
1983年 | 39篇 |
1982年 | 35篇 |
1981年 | 35篇 |
1980年 | 41篇 |
1978年 | 17篇 |
1977年 | 18篇 |
1975年 | 14篇 |
1974年 | 14篇 |
1973年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
In this low-income Turkish sample, parents reported on father and mother division of childcare labor and satisfaction with division. Regardless of whether they were rearing typical or atypical children, mothers reported a higher level of involvement than fathers in every domain of childcare. In general, both mothers and fathers reported slight dissatisfaction with their own level of participation in childcare. Across groups, all mothers were significantly more dissatisfied (than their spouses were with their level of participation) with the fathers' level of participation in childcare. Best predictors of parental involvement were parent's employment status, satisfaction with partner level of involvement, and parent educational level. 相似文献
82.
John S Santelli Javaid Kaiser Lesley Hirsch Alice Radosh Linda Simkin Susan Middlestadt 《The Journal of adolescent health》2004,34(3):200-208
PURPOSE: To explore potential psychosocial predictors for initiation of sexual intercourse among middle-school, inner-city youth, using longitudinal data from the Healthy and Alive! project. METHODS: We conducted hierarchical, logistic regression with adjustment for intraclass correlation over two sequential periods, including seventh and eighth grades (N = 3163), to assess the independent influence of psychosocial and demographic factors. Internally reliable scales to assess psychosocial influences were created, based on major theories of behavior. The sample was 52% female, 51% black, 30% Hispanic, 9% white, and 3% Asian. At baseline, 13% of girls and 39% of boys reported already having initiated sexual intercourse. RESULTS: Personal and perceived peer norms about refraining from sex were a strong and consistent protective factor. Alcohol and other drug use, poor academic performance, male gender, and black race were consistent risk factors. Self-efficacy showed a mixed effect: protective in the seventh grade but increasing risk in the eighth grade. Speaking a language other than English was a protective factor in seventh grade. Both psychosocial and demographic factors provided independent explanatory power. CONCLUSIONS: Psychosocial factors, particularly norms about having sex, influence initiation of sexual intercourse. These data suggest that programs to delay initiation of sexual intercourse should reinforce norms about refraining from sex. 相似文献
83.
Daniela G Beghini Maria Alice da Cruz-H?fling Priscila Randazzo-Moura Léa Rodrigues-Simioni José Camilo Novello Stephen Hyslop Sérgio Marangoni 《Toxicon》2005,46(6):604-611
We have previously demonstrated that rabbit antisera raised against crotoxin from Crotalus durissus cascavella venom (cdc-crotoxin) and its PLA2 (cdc-PLA2) neutralized the neurotoxicity of this venom and its crotoxin. In this study, we examined the ability of these antisera to neutralize the neurotoxicity of Crotalus durissus terrificus and Bothrops jararacussu venoms and their major toxins, cdt-crotoxin and bothropstoxin-I (BthTX-I), respectively, in mouse isolated phrenic nerve-diaphragm preparations. Immunoblotting showed that antiserum to cdc-crotoxin recognized cdt-crotoxin and BthTX-I, while antiserum to cdc-PLA2 recognized cdt-PLA2 and BthTX-I. ELISA corroborated this cross-reactivity. Antiserum to cdc-crotoxin prevented the neuromuscular blockade caused by C. d. terrificus venom and its crotoxin at a venom/crotoxin:antiserum ratio of 1:3. Antiserum to cdc-PLA2 also neutralized the neuromuscular blockade caused by C. d. terrificus venom or its crotoxin at venom or toxin:antiserum ratios of 1:3 and 1:1, respectively. The neuromuscular blockade caused by B. jararacussu venom and BthTX-I was also neutralized by the antisera to cdc-crotoxin and cdc-PLA2 at a venom/toxin:antiserum ratio of 1:10 for both. Commercial equine antivenom raised against C. d. terrificus venom was effective in preventing the neuromuscular blockade typical of B. jararacussu venom (venom:antivenom ratio of 1:2), whereas for BthTX-I the ratio was 1:10. These results show that antiserum produced against PLA2, the major toxin in C. durissus cascavella venom, efficiently neutralized the neurotoxicity of C. d. terrificus and B. jararacussu venoms and their PLA2 toxins. 相似文献
84.
Léa Rodrigues-Simioni Stella R Zamunér José C Cogo Caroline R Borja-Oliveira Júlia Prado-Franceschi Maria Alice da Cruz-H?fling Alexandre P Corrado 《Toxicon》2004,43(6):633-638
Whereas the presynaptic action of Crotalus durissus terrificus venom is well-established, Bothrops venoms have historically been considered to have only postsynaptic and muscular effects. However, some studies have also suggested a presynaptic action for these venoms. In this work, we used chick biventer cervicis preparations to compare the presynaptic actions of two Bothrops venoms (B. insularis and B. neuwiedi) with that of C. d. terrificus venom. At 10 microg/ml, all venoms produced irreversible blockade of the twitch tension responses, with no reduction in acetylcholine (ACh)-induced contractures and only a slight decrease in potassium induced-contractures. The times (in min) required to produce 50% neuromuscular blockade (C. d. terrificus: 16.3+/-0.7, n = 8; B. insularis: 30.0+/-1.9, n = 5; B. neuwiedi: 42.0+/-2.0, n = 8; mean +/- SEM) were significantly different among the venoms (p < 0.01). Lowering the temperature at which the experiments were done (from 37 to 24 degrees C) prevented neuromuscular blockade by the three venoms, indicating that enzyme activity may be involved in this response. At concentrations capable of causing complete neuromuscular blockade, creatine kinase release remained close to levels seen in control preparations incubated with Krebs solution alone (500-1200 IU/l). Commercial crotalic antivenom, but not bothropic antivenom, protected against the neuromuscular blockade caused by B. insularis and B. neuwiedi venoms. These observations indicate that bothropic venoms may contain components which act presynaptically in a manner similar to C. d. terrificus venom, and that at low venom concentrations a direct action on skeletal muscle does not contribute to this presynaptic neurotoxicity. 相似文献
85.
86.
Alice Nourissat MD Isabelle Bairati MD PhD Elodie Samson MSc André Fortin MD MSc Michel Gélinas MD Abdenour Nabid MD François Brochet MD Bernard Têtu MD François Meyer MD DSc 《Cancer》2010,116(9):2275-2283
BACKGROUND:
The purpose of the study was to identify predictors of weight loss during radiotherapy (RT) in patients with stage I or II head and neck (HN) cancer.METHODS:
This study was conducted as part of a phase 3 chemoprevention trial. A total of 540 patients were randomized. The patients were weighed before and after RT. Their baseline characteristics, including lifestyle habits, diet, and quality of life, were assessed as potential predictors. Predictors were identified using multiple linear regressions. The reliability of the model was assessed by bootstrap resampling. A receiver operating characteristics curve was generated to estimate the model's accuracy in predicting critical weight loss (≥5%).RESULTS:
The mean weight loss was 2.2 kg (standard deviation, 3.4). Five factors were associated with a greater weight loss: all HN cancer sites other than the glottic larynx (P<.001), higher pre‐RT body weight (P<.001), stage II disease (P = .002), dysphagia and/or odynophagia before RT (P = .001), and a lower Karnofsky performance score (P = .028). There was no association with pre‐RT lifestyle habits, diet, or quality of life. The bootstrapping method confirmed the reliability of this predictive model. The area under the curve was 71.3% (95% confidence interval, 65.8‐76.9), which represents an acceptable ability of the model to predict critical weight loss.CONCLUSIONS:
These results could be useful to clinicians for screening patients with early stage HN cancer treated by RT who require special nutritional attention. Cancer 2010. © 2010 American Cancer Society. 相似文献87.
Copy number variations in DCC/18q and ERBB2/17q are associated with disease‐free survival in microsatellite stable colon cancer
下载免费PDF全文
![点击此处可从《International journal of cancer. Journal international du cancer》网站下载免费的PDF全文](/ch/ext_images/free.gif)
David Sefrioui Thomas Vermeulin France Blanchard Caroline Chapusot Ludivine Beaussire Laura Armengol‐Debeir Richard Sesboué Alice Gangloff Mohamed Hebbar Marie‐Christine Copin Estelle Houivet Lilian Schwarz Florian Clatot Jean‐Jacques Tuech Jacques Bénichou Laurent Martin Anne‐Marie Bouvier Jean‐Christophe Sabourin Nasrin Sarafan‐Vasseur Thierry Frébourg Côme Lepage Pierre Michel Frédéric Di Fiore 《International journal of cancer. Journal international du cancer》2017,140(7):1653-1661
We conducted a prospective study to assess the prognostic impact of selected copy number variations (CNVs) in Stage II–III microsatellite stable (MSS) colon cancer. A total of 401 patients were included from 01/2004 to 01/2009. The CNVs in 8 selected target genes, DCC/18q, EGFR/7p, TP53/17p, BLK/8p, MYC/8q, APC/5q, ERBB2/17q and STK6/20q, were detected using a quantitative multiplex polymerase chain reaction of short fluorescent fragment (QMPSF) method. The primary end‐point was the impact of the CNVs on the 4‐year disease‐free survival (DFS). The recurrence rate at 4 years was 20.9%, corresponding to 14% Stage II patients versus 31% Stage III patients (p < 0.0001). The 4‐year DFS was significantly decreased in patients with a loss at DCC/18q (p = 0.012) and a gain at ERBB2/17q (p = 0.041). The multivariate analysis demonstrated that Stage III, a loss at DCC/18q and a gain at ERBB2/17q were independent factors associated with DFS. A combination of DCC/18q and ERBB2/17q was also associated with relapse, with the hazard ratio increasing from 1 to 2.4 (95% confidence interval (CI), 1.5–4.1) and 3.1 (95% CI, 1.2–8.4) in the presence of 0, 1 or 2 alterations, respectively (p = 0.0013). CNVs in DCC/18q and ERBB2/17q are significantly associated with DFS in Stage II–III MSS colon cancer. 相似文献
88.
89.
Renan Faustino Fabiana Rabe Carvalho Thalia Medeiros Dbora Familiar-Macedo Renata Artimos de Oliveira Vianna Paulo Emílio Crrea Leite Isabela Resende Pereira Claudete Aparecida Araújo Cardoso Elzinandes Leal De Azeredo Andrea Alice Silva 《Viruses》2022,14(9)
Chikungunya virus (CHIKV) vertical transmission occurs due to maternal viremia in the prepartum. Clinical presentation in neonates can be varied; however, the consequences of intrauterine exposure on the immune response are unclear. Thus, we aimed to analyze inflammatory alterations in children exposed to maternal CHIKV infection. This is a cross-sectional study that included children exposed to maternal CHIKV infection (confirmed by RT-qPCR and/or IgM). Circulant immune mediators were analyzed by a multiplex assay. RESULTS: We included 33 children, with a mean age of 3 ± 2.9 months-old, and 19 (57.6%) were male. Only one child presented neurological alterations. CHIKV-exposed infants showed elevated levels of MIP-1α, MIP-1β, and CCL-2 (p < 0.05). Pro-inflammatory cytokines such as TNFα, IL-6, and IL-7 (p < 0.0001) were also increased. In addition, lower levels of PDGF-BB and GM-CSF were observed in the same group (p < 0.0001). Principal component (PC) analysis highlighted a distinction in the inflammatory profile between groups, where PC explained 56.6% of the alterations. Our findings suggest that maternal exposure to CHIKV can affect the circulating levels of pro-inflammatory cytokines during the infants’ first year of life. The long-term clinical consequences of these findings should be investigated. 相似文献
90.
Lalidia Bruno Ouoba Lamouni Habibata-Zerbo Bianca Zecchin Giacomo Barbierato Sandaogo Hamidou-Ouandaogo Elisa Palumbo Edoardo Giussani Alessio Bortolami Mamadou Niang Adele Traore-Kam Calogero Terregino Maritou Guitti-Kindo Angelique Angot Dominique Guigma Nicolas Barro Alice Fusaro Isabella Monne 《Viruses》2022,14(9)
Since 2006, the poultry population in Burkina Faso has been seriously hit by different waves of Highly Pathogenic Avian Influenza (HPAI) H5N1 epizootics. In December 2021, three distinct regions of Burkina Faso, namely, Gomboussougou, Bonyollo, and Koubri, detected HPAI H5N1 viruses in poultry. Whole genome characterization and statistical phylogenetic approaches were applied to shed light on the potential origin of these viruses and estimate the time of virus emergence. Our results revealed that the HPAI H5N1 viruses reported in the three affected regions of Burkina Faso cluster together within clade 2.3.4.4b, and are closely related to HPAI H5N1 viruses identified in Nigeria and Niger in the period 2021–2022, except for the PA gene, which clusters with H9N2 viruses of the zoonotic G1 lineage collected in West Africa between 2017 and 2020. These reassortant viruses possess several mutations that may be associated with an increased zoonotic potential. Although it is difficult to ascertain where and when the reassortment event occurred, the emergence of a H5N1/H9N2 reassortant virus in a vulnerable region, such as West Africa, raises concerns about its possible impact on animal and human health. These findings also highlight the risk that West Africa may become a new hotspot for the emergence of new genotypes of HPAI viruses. 相似文献