全文获取类型
收费全文 | 6349篇 |
免费 | 445篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 66篇 |
儿科学 | 94篇 |
妇产科学 | 148篇 |
基础医学 | 1127篇 |
口腔科学 | 706篇 |
临床医学 | 424篇 |
内科学 | 1100篇 |
皮肤病学 | 143篇 |
神经病学 | 507篇 |
特种医学 | 253篇 |
外科学 | 509篇 |
综合类 | 58篇 |
一般理论 | 1篇 |
预防医学 | 692篇 |
眼科学 | 58篇 |
药学 | 490篇 |
中国医学 | 59篇 |
肿瘤学 | 392篇 |
出版年
2024年 | 8篇 |
2023年 | 53篇 |
2022年 | 136篇 |
2021年 | 187篇 |
2020年 | 131篇 |
2019年 | 182篇 |
2018年 | 255篇 |
2017年 | 166篇 |
2016年 | 201篇 |
2015年 | 211篇 |
2014年 | 312篇 |
2013年 | 346篇 |
2012年 | 486篇 |
2011年 | 566篇 |
2010年 | 283篇 |
2009年 | 227篇 |
2008年 | 389篇 |
2007年 | 407篇 |
2006年 | 296篇 |
2005年 | 315篇 |
2004年 | 266篇 |
2003年 | 242篇 |
2002年 | 192篇 |
2001年 | 138篇 |
2000年 | 127篇 |
1999年 | 120篇 |
1998年 | 73篇 |
1997年 | 45篇 |
1996年 | 27篇 |
1995年 | 26篇 |
1994年 | 29篇 |
1993年 | 30篇 |
1992年 | 54篇 |
1991年 | 38篇 |
1990年 | 38篇 |
1989年 | 28篇 |
1988年 | 30篇 |
1987年 | 13篇 |
1986年 | 17篇 |
1985年 | 16篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1982年 | 14篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 13篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1973年 | 6篇 |
1971年 | 6篇 |
排序方式: 共有6827条查询结果,搜索用时 15 毫秒
51.
Yasmin Amaral Leila Silva Fernanda Soares Daniele Marano Sylvia Nehab Andrea Abranches Ana Carolina Costa Maria Elisabeth Moreira 《Nutrients》2021,13(5)
Background: To evaluate the potential factors associated with the nutritional composition of human milk of puerperal women. Methods: cross-sectional study, conducted between March 2016 and August 2017, with 107 women, selected in a Tertiary Health Care Tertiary Health Facility of the Unified Health System (SUS) in the Municipality of Rio de Janeiro. Data were collected two months after delivery. The dependent variable of the study was the nutritional composition of human milk. We divided the independent variables into hierarchical levels: distal (age, schooling, parity and pregestational nutritional status), intermediate (number of prenatal visits and gestational weight gain) and proximal (alcohol consumption, smoking, diabetes mellitus and hypertension). For data analysis, we applied the multiple linear regression, centered on the hierarchical model. Only the variables associated with the nutritional composition of breast milk remained in the final model at a 5% level of significance. Results: The nutritional composition of human milk yielded by women with pregestational overweight, smokers and hypertensive had higher amounts of lipids and energy. Conversely, women with gestational weight gain below the recommended had lower amounts of these components. Conclusion: The evaluation of factors associated with the nutritional composition of human milk is extremely important to assist post-partum care practices. In this study, we observed that lipid and energy contents were associated to pregestational nutritional status, gestational weight gain, smoking and hypertension. 相似文献
52.
Markus Walther Victor Valderrabano Martin Wiewiorski Federico Giuseppe Usuelli Martinus Richter Tiago Soares Baumfeld Johanna Kubosch Oliver Gottschalk Udo Wittmann 《Foot and Ankle Surgery》2021,27(3):236-245
BackgroundThe aim of this study is to systematically review the literature on clinical outcomes of patients who have undergone autologous matrix-induced chondrogenesis (AMIC) for treatment of osteochondral lesions of the talus (OCL) and compare the studies’ outcomes.MethodsPubmed and Embase were searched in January 2020 for articles concerning OCL surgery. Studies were included if they had a minimum 1-year follow-up and the primary measures were functional outcomes. The meta-analysis compared the Visual Analogic Score (VAS), the American Orthopedic Foot and Ankle Score (AOFAS), and the Foot Function Index (FFI) between baseline and follow-up of 1?2 years, and 3?5 years. A random effects model was used to evaluate outcome changes.ResultsThe search returned 15 studies, with a total of 492 patients. The VAS improved 4.45 and 4.6 points from baseline to the 1?2 year and 3?5 year follow-up, respectively (p < 0.001). AOFAS improved 31.59 and 32.47 points from baseline to the 1?2 year and 3?5 year follow-up, respectively (p < 0.001). The FFI showed a significant improvement of 30.93 points from baseline to year 3?5 (p < 0.001). A total of 6 patients with revision surgeries have been reported within the follow up period. It was not possible to correlate clinical features like lesion size, surgical approach, and bone marrow stimulation technique to the reported outcome.ConclusionSurgical treatment of OCL via the AMIC procedure provided significant improvement in the functional outcome and pain scores when compared to the pre-operative values. Improvements were observed up to 5 years post-operatively. 相似文献
53.
Sérgio Soares Tiago Mota Gomes Gustavo Campos Filipe Medeiros João Bragança Xavier Martin Oliva 《Foot and Ankle Surgery》2021,27(5):567-576
BackgroundVascular injury after hallux valgus surgery is a rare condition but serious complications can ensue.MethodsWe performed an anatomical study using 26 cadaveric lower extremities. We enhanced first metatarsal bone’s (FMB) vascularization by injecting latex. Each specimen was classified according to the severity of hallux valgus deformity (HVD). Then we measured two distances: one between the first tarsometatarsal joint (FTMJ) to the first dorsal branch’s origin, the other between the first metatarsophalangeal joint (MTP) to the dorsal plexus’s origin.ResultsThe distance between the FTMJ and the first dorsal branch to the FMB ranges from 10 mm in normal feet to 15 mm in severe deformed feet. The distance between the MTP and the dorsal plexus’ origin ranges from 20 mm in normal feet to 25 mm in severe deformed feet.ConclusionsUnderstanding the foot’s vascular anatomy has allowed us to adapt surgical landmarks to the severity of the HVD and to avoid post-operative complications. 相似文献
54.
John Lennon Silva Cunha Carla Isabelly Rodrigues-Fernandes Ciro Dantas Soares Celeste Snchez-Romero Pablo Agustin Vargas Cleverson Luciano Trento Bruno Augusto Benevenuto de Andrade Sílvia Ferreira de Sousa Ricardo Luiz Cavalcanti de Albuquerque-Júnior 《Head and neck pathology》2021,15(1):303
Myofibroma (MF) is a benign mesenchymal myofibroblast-derived tumor, which occurs most frequently in children, and rarely affects the maxilla. We reported a case of an aggressive intraosseous lesion found in the maxilla of a 9-year-old female child. Intraorally, the swelling extended from tooth 12 to 16, causing displacement of teeth 13, 14, and 15. Computed tomography revealed a large osteolytic lesion causing thinning and cortical erosion. Microscopically, the lesion showed a proliferation of spindle-shaped cells, with elongated nuclei and eosinophilic cytoplasm, arranged in interlaced fascicles. The immunohistochemical analysis revealed cytoplasmic positivity for α-SMA and HHF-35, and negativity for desmin, laminin, S-100, β-catenin, and CD34. Ki-67 was positive in 8% of tumor cells. The diagnosis was MF. Herein, we describe an additional case of central MF arising in the maxilla, including clinical, imaging, microscopical, and immunohistochemical features, as well as a review of the literature. 相似文献
55.
Liseana O. Barbosa Jos Osvaldo B. Neto Antnio Augusto L. Teixeira-Júnior Leudivan R. Nogueira Jos de Ribamar R. Calixto Isabela W. Cunha Jaqueline D. Pinho Francisco Srgio M. S. do Nascimento Syomara Pereira da C. Melo Fernando A. Soares Gyl Eanes B. Silva 《Translational andrology and urology》2021,10(4):1803
Pseudoangiosarcomatous squamous cell carcinoma, also called pseudovascular, pseudoangiomatoid or adenoid pseudovascular carcinoma, is an uncommon and highly aggressive variant of squamous cell carcinoma. Histologically, it is characterized by proliferation of atypical keratinocytes with acantholysis and formation of pseudovascular spaces, forming anastomosed channels lined with neoplastic cells that invade the dermis. These cells are positive for cytokeratin and negative for vascular markers such as CD31 and CD34. There are few reports of this variant in the literature. Skin, breast, lung and vulva involvement have been described, but to the best of our knowledge, no cases involving the penis has been described. This study aims to describe the first case of angiosarcomatous squamous cell carcinoma of the penis. The patient presented with a painful lesion in the penis associated with urinary retention. Macroscopic findings exhibited an ulcerative vegetating lesion that involving the entire glans and part of the penile body, as well as infiltration of penile structures and scrotal skin. Microscopy shows atypical proliferation of sarcomatous keratinocyte pattern mimicking vascular spaces. Human papilloma virus (HPV) biomarkers and polymerase chain reaction (PCR) were all negative. Advanced penile squamous cell carcinoma with aggressive lymph node metastasis. This report presents the first case of penile pseudoangiosarcomatous squamous cell carcinoma, as an important differential diagnosis. 相似文献
56.
Dr. Linda K. Green MD Susan Zachariah MS CT David Y. Graham MD 《Digestive diseases and sciences》1990,35(11):1421-1425
Summary Secondary neoplasms of the stomach are rare and are often clinical and diagnostic problems. Three patients with bleeding volcano-like ulcers were diagnosed by combined endoscopic salvage cytology and surgical biopsy as having metastatic submucosal lesions from hematologic spread. The combination of endoscopic appearance, clinical findings, and tissue and cytologic examination can lead to the correct diagnosis. The results from these cases support the utility of this cytologic technique in combination with biopsy in this clinical setting. 相似文献
57.
A. K. Miles C. E. Grue G. W. Pendleton J. H. Soares Jr. 《Archives of environmental contamination and toxicology》1993,24(2):206-212
Egg and bone of passerine birds nesting in acidified habitats may be affected by high levels of Al or P, or low levels of Ca. Nine treatments of three levels of dietary Al (target levels of 200, 1,000, and 5,000 g/g) and three levels of Ca:P (target levels of NN = 1.3% Ca: 0.9% P; LL = 0.19 Ca:0.45 P; LH = 0.19 Ca: 1.65 P) were fed to 16–17 starling pairs during two breeding seasons. Eggs of starlings fed the LH diet were smaller and weighed less than eggs from the NN and LL treatments. Treatment effects on thickness, strength, and weight of eggshells were not consistent between seasons, probably because of differences in actual dietary levels of Al, Ca, and P or in incubation intervals. In one season, birds fed the highest Al diet had thicker eggshells than those from the other Al treatments (no effect from Ca:P); the following season, eggshells from the NN and LH treatments were thicker and stronger than those from the LL treatment. Eggshells from the NN treatment weighed more than those from the other Ca:P treatments. Starlings on the LH diet had the strongest femurs, but the effect was interactive with different levels of dietary Al. Effects of Ca:P on egg and bone were more evident than Al effects. 相似文献
58.
59.
Several techniques have been developed to assess the ecotoxicity of contaminated watercourses. Most of these techniques involve chemical alterations of water samples, by diluting it or by adding chelating agents. These changes become particularly severe when assessing the toxicity of samples with very low pH and with high quantities of contaminants. Trying to overcome this problem, a novel toxicity test, specific for acid waters, was previously developed and field validated. The toxicity of acid samples is assessed using the survival time of Ceriodaphnia dubia. During this study, the novel test was applied to a field situation, where an aquatic system is seriously impacted with acid mine drainage. Its efficiency was tested and compared with two classical toxicity tests: the Microtox and the median lethal dilution with C. dubia. The survival time test was performed without adjusting pH and after adjusting pH to a fixed value (pH 2, 3, and 4). At pH 2 and 4 no acceptable results were obtained; at pH 3 it was possible to distinguish the toxicity due to pH from the toxicity due to other toxicants. The test conducted at local pH was able to discriminate toxicity sources only for highly contaminated samples. The toxicity evaluation of acid mine drainage samples was possible neither with the median lethal dilution test nor with Microtox. 相似文献
60.
Ribeiro S Guilhermino L Sousa JP Soares AM 《Ecotoxicology and environmental safety》1999,44(3):287-293
This study developed a bioassay with the isopod Porcellio dilatatus based on the activity of the enzymes acetylcholinesterase (AChE) and lactate dehydrogenase (LDH). The in vivo effects of the insecticides parathion-ethyl and endosulfan-sulfate on AChE and LDH activities of P. dilatatus under laboratory conditions were investigated. The route of uptake of the pesticides was through the food (alder leaves). Isopods were exposed to a wide range of concentrations of parathion or endosulfan (0.1, 1, 10, 25, 50, 100, 250, and 500 microg/g of food) for 21 days. After this period, the activity of AChE and LDH was determined. Parathion induced significant depression of both AChE and LDH activities. Animals fed with endosulfan-contaminated food exhibited lower LDH activities than control animals, while AChE activity was similar in all treatments. The results of the present investigation suggest that the isopod. P. dilatatus is a suitable species for use in toxicity tests and indicate that the enzymes AChE and LDH could be used as effect criteria both in laboratory and in field studies with this species. 相似文献