全文获取类型
收费全文 | 2612篇 |
免费 | 56篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 85篇 |
儿科学 | 52篇 |
妇产科学 | 26篇 |
基础医学 | 513篇 |
口腔科学 | 286篇 |
临床医学 | 185篇 |
内科学 | 190篇 |
皮肤病学 | 25篇 |
神经病学 | 176篇 |
特种医学 | 175篇 |
外科学 | 245篇 |
综合类 | 282篇 |
预防医学 | 127篇 |
眼科学 | 66篇 |
药学 | 154篇 |
中国医学 | 42篇 |
肿瘤学 | 73篇 |
出版年
2023年 | 15篇 |
2022年 | 51篇 |
2021年 | 50篇 |
2020年 | 44篇 |
2019年 | 56篇 |
2018年 | 58篇 |
2017年 | 53篇 |
2016年 | 65篇 |
2015年 | 58篇 |
2014年 | 115篇 |
2013年 | 116篇 |
2012年 | 86篇 |
2011年 | 122篇 |
2010年 | 100篇 |
2009年 | 123篇 |
2008年 | 89篇 |
2007年 | 116篇 |
2006年 | 101篇 |
2005年 | 97篇 |
2004年 | 81篇 |
2003年 | 77篇 |
2002年 | 67篇 |
2001年 | 48篇 |
2000年 | 46篇 |
1999年 | 50篇 |
1998年 | 56篇 |
1997年 | 38篇 |
1996年 | 54篇 |
1995年 | 44篇 |
1994年 | 59篇 |
1993年 | 41篇 |
1992年 | 29篇 |
1991年 | 44篇 |
1990年 | 43篇 |
1989年 | 31篇 |
1988年 | 43篇 |
1987年 | 40篇 |
1986年 | 28篇 |
1985年 | 46篇 |
1984年 | 24篇 |
1983年 | 13篇 |
1982年 | 28篇 |
1981年 | 18篇 |
1980年 | 25篇 |
1979年 | 26篇 |
1978年 | 25篇 |
1977年 | 22篇 |
1976年 | 20篇 |
1974年 | 9篇 |
1972年 | 5篇 |
排序方式: 共有2702条查询结果,搜索用时 31 毫秒
1.
Glaucoma, an irreversible blinding condition affecting 3–4% adults aged above 40 years worldwide, is set to increase with a rapidly aging global population. Raised intraocular pressure (IOP) is a major risk factor for glaucoma where the treatment paradigm is focused on managing IOP using medications, laser, or surgery regimens. However, notwithstanding IOP and other clinical parameters, patient-reported outcomes, including daily functioning, emotional well-being, symptoms, mobility, and social life, remain the foremost concerns for people being treated for glaucoma. These outcomes are measured using objective patient-centered outcome measures (PCOMs) and subjective patient-reported outcome measures (PROMs). Studies using PCOMs have shown that people with glaucoma have several mobility, navigational and coordination challenges; reading and face recognition deficits; and are slower in adapting to multiple real-world situations when compared to healthy controls. Similarly, studies have consistently demonstrated, using PROMs, that glaucoma substantially and negatively impacts on peoples’ self-reported visual functioning, mobility, independence, emotional well-being, self-image, and confidence in healthcare, compared to healthy individuals, particularly in those with late-stage disease undergoing a heavy treatment regimen. The patient-centred effectiveness of current glaucoma treatment paradigms is equivocal due to a lack of well-designed randomized controlled trials; short post-treatment follow-up periods; an inappropriate selection or availability of PROMs; and/or an insensitivity of currently available PROMs to monitor changes especially in patients with newly diagnosed early-stage glaucoma. We provide a comprehensive, albeit non-systematic, critique of the psychometric properties, limitations, and recent advances of currently available glaucoma-specific PCOMs and PROMs. Finally, we propose that item banking and computerized adaptive testing methods can address the multiple limitations of paper-pencil PROMs; customize their administration; and have the potential to improve healthcare outcomes for people with glaucoma. 相似文献
2.
《Gaceta sanitaria / S.E.S.P.A.S》2015,29(5):390-392
Chronic obstructive pulmonary disease (COPD) is a significant health problem in developed countries. We aimed to estimate the prevalence of COPD in a single Spanish healthcare area. We also aimed to assess if there are any differences in prevalence and spirometry use among primary care services by utilizing already registered information. We designed a cross-sectional study to determine the prevalence of COPD and the performance of spirometries in each primary care service. A total of 8,444 patients were diagnosed with COPD, with a prevalence of 2.6% for individuals older than 39 years. The prevalence increased with age and was much higher in men. Significant heterogeneity was found in the prevalence of COPD and spirometry use among primary care services. COPD was underdiagnosed and there was wide variability in spirometry use in our area. Greater efforts are needed to diagnose COPD in order to improve its clinical outcomes and to refine registries so that they can be used as reliable sources of information 相似文献
3.
4.
目的 本研究使用激光扫描检眼镜(SLO)评价双侧中央暗点患者使用棱镜后的眼球运动反应.方法 本预试验共招募6例有双侧中央暗点的年龄相关性黄斑变性(AMD)患者以及6例正常视力的志愿者.首先用Nidek MP-1微视野仪确认患者的中央暗点和优选视网膜注视点(PRL),然后用Rodenstock SLO,在将视标投射在优选视网膜注视点时拍下实时视网膜像,接着在受检者眼前加入6~8 PD的棱镜,要求受检者保持注视视标,这时通过视网膜标记来测量视网膜像的移位量,以及随后发生的优选视网膜注视点的再次注视.过程中平均移位量和再次注视时间通过图像软件(ImageJ software)来计算.结果 实验组再次注视时的移位量在3个像素点或11.66个弧分之内(x轴:2.90±3.92,y轴:2.53±4.18).对照组再次注视时的移位会准确些(x轴:0.33±1.15,y轴:0.89±2.50),但与实验组差异无统计学意义(tx=1.32,Px>0.05;ty=0.80,Py>0.05).对照组再次注视时间(0.98±0.19)s较实验组(2.83±1.63)s要短,差距有统计学意义(t=5.03,P<0.01).其中有1例实验组受检者没有发生再次注视,其结果被排除并单独分析.结论 研究发现,双眼中央暗点患者对棱镜物像转移后的再注视反应与正常人接近,但实验组再注视明显较对照组慢,并有1例受检者没有发生再注视.该数据说明双侧中央暗点患者无论眼前有没有棱镜,都会利用相同的视网膜位置视物,因此,通过棱镜物像再定位的意义不大. 相似文献
5.
甲氧苄氨嘧啶—PVP共沉淀物的研究 总被引:1,自引:0,他引:1
本工作用差示扫描量热法(DSC)研究甲氧苄氨嘧啶与PVP溶剂法制备的共沉淀物,表明已不存在甲氧苄氨嘧啶晶体。用x射线衍射法研究了1:12共沉淀物,证明无甲氧苄氨嘧啶的晶体衍射峰。经分光光度法测定结果,1:12共沉淀物比原药的溶解度大28.3倍。 相似文献
6.
G.E. ORLANDINI S. ZECCHI ORLANDINI A.F. HOLSTEIN R. EVANGELISTI and R. PONCHIETTI 《Andrologia》1987,19(3):315-321
The human prostatic urethra has been investigated by means of scanning electron microscopy. On the posterior wall of the urethra, the seminal colliculus with the orifices of the ejaculatory ducts is clearly detectable. The upper portion of the prostatic urethra shows a typical transitional epithelium with large superficial cells of a ruffled appearance. In the lower portion of the organ (underneath the openings of the ejaculatory ducts), the apical pattern of the cells varies considerably. Four main aspects are recognizable: apices provided with microvilli, dome-shaped apices with an almost smooth surface, large apices with labyrinthic microplicae and ciliated apices. Also, apices showing intermediate characteristics can be noted. The functional significance of the morphological patterns as well as the possibility of a transition among the various types of surface structures are discussed. 相似文献
7.
本文用扫描电镜观察了6.25Gy全身照射后大鼠外周血红细胞表面形态的变化。于照前和照后l、3、7、14和30天取材,在2000倍率下各观察200个细胞,并算出正常和异形细胞的百分数。正常红细胞的形态是光滑的、双面凹的圆盘形,其直径3.3~5.2μ,照射前正常红细胞占总数98.15%(96.0~99.0%),异形红细胞很少。其中包括单嵴样红细胞,隆突形红细胞、球口形红细胞以及棘状红细胞等。照后1和3天,异形红细胞数明显增多,正常形态红细胞的百分数从照前的88.15分别降到96.55和93.45(P<0.05和P<0.001)。照后7天,正常形态红细胞的百分数又接近照前水平。 相似文献
8.
The electrodeposition of Ag on Pt(100)-(1 × 1) in perchlorate electrolyte was studied by means of time-resolved in situ scanning tunnelling microscopy (STM) and cyclic voltammetry. One monolayer of Ag is deposited underpotentially (upd) ca. 500 mV positive of the Ag+/Ag equilibrium potential. Several millivolts positive of the equilibrium potential, a second well defined upd layer forms. Its growth was observed to proceed via island formation and coalescence. This process occurs in two separate stages that manifest themselves in voltammetric peaks as well as in the STM images. 相似文献
9.
Peritoneal morphology in children treated by continuous ambulatory peritoneal dialysis 总被引:2,自引:0,他引:2
Fritz Schneble Klaus-Eugen Bonzel Rüdiger Waldherr Sebastian Bachmann Helga Roth Karl Schärer 《Pediatric nephrology (Berlin, Germany)》1992,6(6):542-546
Fifty peritoneal biopsies (PB) from 35 patients with end-stage renal disease, treated by continuous ambulatory peritoneal dialysis (CAPD) and aged 2 months to 18 years, were examined by light microscopy (n=50) and/or scanning electron microscopy. PB were performed during surgical procedures immediately before the start of, during, or after the cessation of CAPD treatment. PB from 15 children without renal disease undergoing laparatomy were examined similarly. Before the start of CAPD, a scarcity and shortening of the mesothelial microvilli was observed by scanning electron microscopy. During and after CAPD, variable alterations of mesothelium, interstitium and capillaries were found. The mesothelial layer was absent in all 5 PB obtained during episodes of active peritonitis. In patients treated by CAPD for longer than 6 months, mesothelial denudation was observed more frequently (6/11) than in children treated for shorter periods (1/7) (P<0.08). Fibrosis of the peritoneal membrane was present in about 50% of patients during or after the cessation of CAPD without impairment of peritoneal function. No correlation was found between the presence of fibrosis and the frequency of peritonitis or the duration of CAPD treatment. 相似文献
10.
Morphologic characterization of osteoblast-like cell cultures isolated from newborn rat calvaria 总被引:4,自引:0,他引:4
Dominique Masquelier Béatrice Herbert Nadine Hauser Pascal Mermillod Edgard Schonne Claude Remacle Ph.D. 《Calcified tissue international》1990,47(2):92-104
Summary Two methods for harvesting osteoblast-like cell populations from newborn (10 days) rat calvaria were compared. The first one
consisted in culturing the periosteum-free bones and then trypsinizing the cells on the bone surface. The second one involved
the migration of the osteoblasts on glass fragments before trypsinization. Since the plating efficiency, the proportion of
alkaline phosphatase-positive cells, the population doubling time, and the calcium deposition were more adequate, the second
method was used to further characterize the behavior of the cultures. During the first week of culture, the cells featured
shapes similar to those observedin vivo on the surface of periosteum-free calvaria. They formed multilayers and, in the presence of ascorbic acid, synthetized an
organic matrix containing exclusively type I collagen. Later, small amounts of type III collagen appeared. The cells were
embedded in the matrix and progressively acquired the morphologic phenotype of osteocyte-like cells. The matrix mineralized
in the presence of β-glycerophosphate. The technique of dropinoculation (high concentration of cells in a small volume of
medium) promoted the multilayer formation and the achievement of large mineralized plates (about 1 cm2) in 3 weeks of culture. 相似文献