全文获取类型
收费全文 | 6617篇 |
免费 | 414篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 98篇 |
儿科学 | 159篇 |
妇产科学 | 129篇 |
基础医学 | 864篇 |
口腔科学 | 626篇 |
临床医学 | 489篇 |
内科学 | 1331篇 |
皮肤病学 | 120篇 |
神经病学 | 497篇 |
特种医学 | 146篇 |
外科学 | 875篇 |
综合类 | 188篇 |
一般理论 | 3篇 |
预防医学 | 563篇 |
眼科学 | 115篇 |
药学 | 486篇 |
1篇 | |
中国医学 | 87篇 |
肿瘤学 | 320篇 |
出版年
2024年 | 7篇 |
2023年 | 76篇 |
2022年 | 94篇 |
2021年 | 264篇 |
2020年 | 192篇 |
2019年 | 224篇 |
2018年 | 256篇 |
2017年 | 194篇 |
2016年 | 218篇 |
2015年 | 245篇 |
2014年 | 341篇 |
2013年 | 387篇 |
2012年 | 577篇 |
2011年 | 579篇 |
2010年 | 305篇 |
2009年 | 221篇 |
2008年 | 406篇 |
2007年 | 388篇 |
2006年 | 371篇 |
2005年 | 358篇 |
2004年 | 259篇 |
2003年 | 218篇 |
2002年 | 204篇 |
2001年 | 92篇 |
2000年 | 86篇 |
1999年 | 67篇 |
1998年 | 27篇 |
1997年 | 23篇 |
1996年 | 27篇 |
1995年 | 22篇 |
1994年 | 15篇 |
1993年 | 15篇 |
1992年 | 18篇 |
1991年 | 23篇 |
1990年 | 25篇 |
1989年 | 32篇 |
1988年 | 22篇 |
1987年 | 12篇 |
1986年 | 21篇 |
1985年 | 27篇 |
1984年 | 15篇 |
1980年 | 9篇 |
1979年 | 13篇 |
1977年 | 8篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1974年 | 9篇 |
1971年 | 10篇 |
1969年 | 14篇 |
1967年 | 8篇 |
排序方式: 共有7097条查询结果,搜索用时 406 毫秒
1.
Caio Henrique de Carvalho Assuno Júlio Csar Trabanco Raquel Fornaziero Gomes Renata Rodrigues Moreira Alessandra Giannella Samelli 《La Medicina del lavoro》2019,110(4):304
Objective:The present study evaluates a training program for fitting different hearing protection devices (HPDs) based on personal attenuation rating (PAR) before, immediately after, and six months after training.Methods:A total of 67 workers from a public university in the city of São Paulo, Brazil, were invited to participate in the measurement of PARs for foam and silicone protectors through the 3M™ E-A-Rfit Validation System. Two evaluations were performed for each protector at each sampling date: one after reading printed material (the package instructions) and another after being trained by an audiologist. The same procedures were repeated after six months. The final sample consisted of 30 individuals. ANOVA was used for statistical analysis.Results:Larger PAR values were observed after training by the audiologist, and smaller values were observed after six months. Then, after re-training, the values increased again. There were no statistically significant differences in PAR among the HPDs tested. Even after the two training sessions, 23 to 27% of the subjects did not obtain adequate PAR values.Conclusion:These findings emphasize the need for continual worker training in the correct fit of earplug HPDs and the importance of longitudinal PAR monitoring. In addition, some workers, despite the training provided, did not adapt to the HPDs used. Therefore, it is essential that other protection methods and/or other HPD types are made available to these individuals.Key words: Hearing, noise-induced hearing loss, occupational health, personal protective equipment, hearing protection devices 相似文献
2.
Del Lama Rafael Silva Candido Raquel Mariana Chiari-Correia Natália Santana Nogueira-Barbosa Marcello Henrique de Azevedo-Marques Paulo Mazzoncini Tinós Renato 《Journal of digital imaging》2022,35(3):446-458
Journal of Digital Imaging - Vertebral Compression Fracture (VCF) occurs when the vertebral body partially collapses under the action of compressive forces. Non-traumatic VCFs can be secondary to... 相似文献
3.
4.
Talita da Silva Mendes de Farias Ariclécio Cunha de Oliveira Sandra Andreotti Fernanda Gaspar do Amaral Patrícia Chimin André Ricardo Alves de Proença Francisco Leonardo Torres Leal Rogério Antonio Laurato Sertié Amanda Baron Campana Andressa Bolsoni Lopes Arnaldo Henrique de Souza José Cipolla‐Neto Fabio Bessa Lima 《Journal of pineal research》2015,58(3):251-261
Melatonin, the main hormone produced by the pineal gland, is secreted in a circadian manner (24‐hr period), and its oscillation influences several circadian biological rhythms, such as the regulation of clock genes expression (chronobiotic effect) and the modulation of several endocrine functions in peripheral tissues. Assuming that the circadian synchronization of clock genes can play a role in the regulation of energy metabolism and it is influenced by melatonin, our study was designed to assess possible alterations as a consequence of melatonin absence on the circadian expression of clock genes in the epididymal adipose tissue of male Wistar rats and the possible metabolic repercussions to this tissue. Our data show that pinealectomy indeed has impacts on molecular events: it abolishes the daily pattern of the expression of Clock, Per2, and Cry1 clock genes and Pparγ expression, significantly increases the amplitude of daily expression of Rev‐erbα, and affects the pattern of and impairs adipokine production, leading to a decrease in leptin levels. However, regarding some metabolic aspects of adipocyte functions, such as its ability to synthesize triacylglycerols from glucose along 24 hr, was not compromised by pinealectomy, although the daily profile of the lipogenic enzymes expression (ATP‐citrate lyase, malic enzyme, fatty acid synthase, and glucose‐6‐phosphate dehydrogenase) was abolished in pinealectomized animals. 相似文献
5.
6.
Laysa Toschi Martins Henrique Ravanhol Frigeri Caio Cesar Silva de Castro Marcelo Távora Mira 《Experimental dermatology》2020,29(6):535-538
The aetiology of vitiligo has not been fully elucidated, and several hypotheses have been investigated; among them, the most explored assumes an autoimmune basis for the disease. Supporting this hypothesis is the frequent co-occurrence of autoimmune diseases with vitiligo. In addition, various genetic loci associated with vitiligo harbour key immune response genes. Our general hypothesis is that autoimmunity-associated genes participate in the control of vitiligo susceptibility. To investigate this hypothesis, we tested for association between vitiligo and genes CYP27B1, REL, TNFAIP3 and IL2/IL21, all previously related to autoimmune diseases associated with vitiligo. The study was performed using two independent population samples: a family-based discovery set (211 trios) and a replication set (131 cases/119 controls). Statistically significant association with vitiligo was detected between markers of the REL and IL2 gene in the family-based sample. Both association signals were concentrated among patients displaying autoimmune comorbidity and non-segmental vitiligo. Evidence for validation was detected for IL2 marker. Our findings suggest REL and IL2 as new vitiligo susceptibility genes and reinforce the hypothesis of a shared genetic mechanism controlling vitiligo and other autoimmune diseases. 相似文献
7.
Y. Patrice Le Treut M.D. Jean Hardwigsen M.D. Pascal Ananian M.D. Jean Saïsse M.D. Emilie Grégoire M.D. Hubert Richa M.D. Pierre Campan M.D. 《Journal of gastrointestinal surgery》2006,10(6):855-862
Tumor thrombus in major vasculature is a frequent finding with a poor long-term prognosis in patients with hepatocellular
carcinoma (HCC). The utility of surgical resection is still controversial. This study compared morbidity and survival after
resection for HCC with and without tumor thrombus. Data of 108 patients who underwent major hepatic resection for HCC were
prospectively recorded. Patients were divided into two groups. The venous thrombectomy (VT) group included 26 patients who
had HCC with tumor thrombus in the portal or hepatic veins. The matched control group included 82 patients who had HCC without
tumor thrombus. Surgical technique, early outcome, and late survival were analyzed in each group. Multivariate analysis was
performed to assess the prognostic value of this feature. Surgical technique was comparable in the VT and control group with
regard to extent of hepatectomy, procedure duration, and transfusion requirements. Early postoperative outcome was also comparable.
Actuarial survival at 1, 3, and 5 years was 38%, 20%, and 13%, respectively, in the VT group (median: 9 months) versus 74%,
56%, and 33%, respectively, in the control group (median: 41 months). In the subgroup of patients with tumor thrombus limited
to the portal vein, actuarial survival at 1, 3, and 5 years was 50%, 26%, and 17%, respectively, (median: 12 months) and two
patients lived longer than 5 years. Multivariate analysis showed that incomplete resection, alphafetoprotein level greater
than 100 N, more than two tumor nodules, and tumor thrombus in major vasculature were independent factors of poor prognosis.
Survival after resection for HCC with tumor thrombus in the major vasculature is poorer than after resection for HCC without
tumor thrombus. However, an aggressive surgical strategy can provide significant survival with comparable morbidity in selected
cases, that is, tumor thrombus located in the portal vein only and expected complete resection of the lesions. 相似文献
8.
9.
J. Saßmannshausen N. Bornfeld A. Kluge W. Sauerwein F. Härting A. Wessing 《International ophthalmology》1989,13(4):243-251
Advanced malignant melanomas of the uvea unsuited for an eye salvaging approach require enucleation of the tumor containing eye. A series of 68 patients is reported who underwent enucleation combined with insertion of a spherical dura-encased implant after 30 Gray pre-irridiation therapy of the orbit. Postoperative results with special attention to cosmetic outcome and motility of the prosthesis suggest that the insertion of an orbital implant should be preferred to the enucleation with no implant. 相似文献
10.
目的:获得较高比例的已分化表皮细胞,为表皮细胞去分化研究奠定基础.方法:采用常规表皮细胞培养方法对人表皮角质细胞系(HEK)进行培养和传代.每一代细胞均通过免疫细胞化学染色和Western blot 方法进行表皮干细胞和表皮细胞相应标志物的检测,包括β1整合素、角蛋白19(K19)、角蛋白10(K10)等指标.结果:第1代HEK呈克隆样生长,表皮干细胞标志物β1整合素、K19均有高表达,而K10的表达为阴性.经过数次传代,细胞克隆形成数目减少,细胞逐渐呈分散分布,K10的表达逐渐增高,而β1整合素、K19的表达呈下降趋势,比例减少.细胞培养至第5~6代时,为其生长的一个转折点,即此时细胞增殖能力开始明显降低,但形态良好,K10表达阳性细胞比例明显增高,而β1整合素、K19表达阳性细胞比例迅速降低.细胞培养至10~11代时,为其生长的第二个转折点,此时细胞几乎丧失增殖能力,数量显著减少,体积变大,核浆比明显减小,完全见不到β1整合素、K19表达阳性细胞,K10染色均为阳性.结论:可以选取适当代数的HEK用于去分化研究,为增加HEK的新用途提供了实验基础. 相似文献