全文获取类型
收费全文 | 2272篇 |
免费 | 152篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 27篇 |
妇产科学 | 43篇 |
基础医学 | 317篇 |
口腔科学 | 126篇 |
临床医学 | 211篇 |
内科学 | 417篇 |
皮肤病学 | 70篇 |
神经病学 | 257篇 |
特种医学 | 77篇 |
外科学 | 352篇 |
综合类 | 8篇 |
预防医学 | 174篇 |
眼科学 | 20篇 |
药学 | 155篇 |
中国医学 | 16篇 |
肿瘤学 | 146篇 |
出版年
2023年 | 43篇 |
2022年 | 74篇 |
2021年 | 137篇 |
2020年 | 87篇 |
2019年 | 121篇 |
2018年 | 123篇 |
2017年 | 86篇 |
2016年 | 89篇 |
2015年 | 91篇 |
2014年 | 128篇 |
2013年 | 138篇 |
2012年 | 190篇 |
2011年 | 178篇 |
2010年 | 93篇 |
2009年 | 66篇 |
2008年 | 97篇 |
2007年 | 97篇 |
2006年 | 93篇 |
2005年 | 70篇 |
2004年 | 72篇 |
2003年 | 55篇 |
2002年 | 47篇 |
2001年 | 20篇 |
2000年 | 32篇 |
1999年 | 19篇 |
1998年 | 9篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 14篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 14篇 |
1986年 | 9篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 9篇 |
1982年 | 3篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1975年 | 5篇 |
1974年 | 10篇 |
1973年 | 6篇 |
1972年 | 5篇 |
1971年 | 3篇 |
1966年 | 4篇 |
排序方式: 共有2437条查询结果,搜索用时 15 毫秒
31.
A prospective study of 50 adults treated with fusion, realignment, and segmental spinal instrumentation for spinal deformity was conducted to assess the safety, accuracy, and efficacy of the free-hand pedicle screw placement technique. Postoperative computed tomographic scans were performed to evaluate the placement of 282 screws and were correlated with patients' clinical outcomes. Five screws were placed at T12, 26 at L1, 39 at L2, 48 at L3, 73 at L4, 35 at L5, and 50 at S1. Nine screws (3%) were misplaced and included three screws (1.06%) that violated the medial wall with no clinical sequelae or revision surgery needed. There were no neurologic deficits related to screw placement. The free-hand technique is a safe and cost-effective method for pedicular screw placement during surgery for adult spine deformities. 相似文献
32.
33.
34.
Stefano Vassanelli Mufti Mahmud Stefano Girardi Marta Maschietto 《Cognitive computation》2012,4(1):71-81
Brain-chip-interfaces (BCHIs) are hybrid entities where chips and nerve cells establish a close physical interaction allowing the transfer of information in one or both directions. Typical examples are represented by multi-site-recording chips interfaced to cultured neurons, cultured/acute brain slices, or implanted ??in vivo??. This paper provides an overview on recent achievements in our laboratory in the field of BCHIs leading to enhancement of signals transmission from nerve cells to chip or from chip to nerve cells with an emphasis on in vivo interfacing, either in terms of signal-to-noise ratio or of spatiotemporal resolution. Oxide-insulated chips featuring large-scale and high-resolution arrays of stimulation and recording elements are presented as a promising technology for high spatiotemporal resolution interfacing, as recently demonstrated by recordings obtained from hippocampal slices and brain cortex in implanted animals. Finally, we report on an automated tool for processing and analysis of acquired signals by BCHIs. 相似文献
35.
Liz Girardi Müller Camila Simonetti Pase Patrícia Reckziegel Raquel C.S. Barcelos Nardeli Boufleur Ana Cristina P. Prado Roseane Fett Jane Mara Block Maria Amália Pavanato Liliane F. Bauermann João Batista Teixeira da Rocha Marilise Escobar Burger 《Experimental and toxicologic pathology》2013,65(1-2):165-171
The hepatoprotective activity of the aqueous extract of the shells of pecan nut was investigated against ethanol-induced liver damage. This by-product of the food industry is popularly used to treat toxicological diseases. We evaluated the phytochemical properties of pecan shell aqueous extract (AE) and its in vitro and ex vivo antioxidant activity. The AE was found to have a high content of total polyphenols (192.4 ± 1.9 mg GAE/g), condensed tannins (58.4 ± 2.2 mg CE/g), and antioxidant capacity, and it inhibited Fe2+-induced lipid peroxidation (LP) in vitro. Rats chronically treated with ethanol (Et) had increased plasmatic transaminases (ALT, AST) and gamma glutamyl transpeptidase (GGT) levels (96%, 59.13% and 465.9%, respectively), which were effectively prevented (87; 41 and 383%) by the extract (1:40, w/v). In liver, ethanol consumption increased the LP (121%) and decreased such antioxidant defenses as glutathione (GSH) (33%) and superoxide dismutase (SOD) (47%) levels, causing genotoxicity in erythrocytes. Treatment with pecan shell AE prevented the development of LP (43%), GSH and SOD depletion (33% and 109%, respectively) and ethanol-induced erythrocyte genotoxicity. Catalase activity in the liver was unchanged by ethanol but was increased by the extract (47% and 73% in AE and AE + Et, respectively). Therefore, pecan shells may be an economic agent to treat liver diseases related to ethanol consumption. 相似文献
36.
Bruna Leonel Carlos Jéssica Suzuki Yamanaka Gabriela Rezende Yanagihara Ana Paula Macedo Plauto Christopher Aranha Watanabe João Paulo Mardegan Issa 《Journal of biomaterials science. Polymer edition》2013,24(14):1291-1307
AbstractNatural latex extracted from Hevea brasiliensis is one of the materials pointed out as potential tissue regenerators. The use of latex-based membranes in bone regeneration might be an alternative to stimulate bone formation. The aim of this study was to evaluate the effects of latex membranes in guided bone regeneration of defects produced in long bones of rats. Sixty rats were equally divided into latex and control groups, and each group was subdivided into two subgroups according to treatment duration of 1 and 4 weeks. Bone defects with 2.5?mm in diameter were surgically made in the left tibia. In the animals of the latex group, a latex membrane was placed over the bone defect. The samples underwent quantitative histological analysis of bone formation and collagen matrix, immunohistochemical analysis of osteogenic protein markers, assessment of bone mechanical properties and bone densitometry, and radiological assessment. The osteocalcin immunostaining data were submitted to the generalized linear model test with two independent factors. For the other data, the multivariate ANOVA with two independent factors was performed. The use of the latex membrane significantly improved (p?<?0.005) the volume of newly formed bone, collagen type I matrix, expression of osteopontin, and bone stiffness, both in the early and late stages of regeneration. In conclusion, the latex membrane was able to promote bone regeneration in long bones. 相似文献
37.
38.
39.
40.
Camila Bruna de Lima Mariana Camargo Daniel Suslik Zylbersztejn Agnaldo Pereira Cedenho Ricardo Pimenta Bertolla 《Human fertility (Cambridge, England)》2017,20(1):48-54
This observational study aimed to establishing a relationship between lipid peroxidation and endometriosis in women undergoing controlled ovarian hyperstimulation. A total of 79 women were divided into two groups: (i) controls (tubal or male factor); and (ii) endometriosis (stages III/IV). The endometriosis diagnosis was confirmed by videolaparoscopy and the controlled ovarian stimulation protocol was similar to all patients. Follicular fluid (FF) lipid peroxidation levels were determined through the quantification of malondialdehyde. Statistical analysis was performed using parametric and non-parametric tests, logistic regression was performed to estimate the chance of achieving a pregnancy in each group and a moving average was calculated for the endometriosis group. Peroxidation levels in the endometriosis group were significantly higher when compared to controls. The moving average showed a decrease of MDA levels in the endometriosis group with increasing female age. Moreover, women with endometriosis who were under 33 years of age were 4.3 times more likely to achieve a pregnancy than women above that age. In conclusion, endometriosis is associated with increased FF oxidative stress (OS) in patients undergoing in vitro fertilization (IVF). Also, increasing age is associated with a decrease in severity of the oxidative status, but a decreased chance of pregnancy. 相似文献