全文获取类型
收费全文 | 24747篇 |
免费 | 1869篇 |
国内免费 | 598篇 |
专业分类
耳鼻咽喉 | 766篇 |
儿科学 | 789篇 |
妇产科学 | 370篇 |
基础医学 | 3499篇 |
口腔科学 | 1649篇 |
临床医学 | 1908篇 |
内科学 | 2217篇 |
皮肤病学 | 445篇 |
神经病学 | 1189篇 |
特种医学 | 1484篇 |
外国民族医学 | 8篇 |
外科学 | 3092篇 |
综合类 | 2790篇 |
现状与发展 | 4篇 |
一般理论 | 1篇 |
预防医学 | 722篇 |
眼科学 | 845篇 |
药学 | 1216篇 |
18篇 | |
中国医学 | 396篇 |
肿瘤学 | 3806篇 |
出版年
2024年 | 68篇 |
2023年 | 361篇 |
2022年 | 777篇 |
2021年 | 921篇 |
2020年 | 875篇 |
2019年 | 751篇 |
2018年 | 746篇 |
2017年 | 747篇 |
2016年 | 809篇 |
2015年 | 857篇 |
2014年 | 1409篇 |
2013年 | 1489篇 |
2012年 | 1254篇 |
2011年 | 1256篇 |
2010年 | 1150篇 |
2009年 | 1032篇 |
2008年 | 1121篇 |
2007年 | 1071篇 |
2006年 | 1009篇 |
2005年 | 918篇 |
2004年 | 777篇 |
2003年 | 669篇 |
2002年 | 553篇 |
2001年 | 534篇 |
2000年 | 457篇 |
1999年 | 441篇 |
1998年 | 449篇 |
1997年 | 426篇 |
1996年 | 417篇 |
1995年 | 348篇 |
1994年 | 356篇 |
1993年 | 292篇 |
1992年 | 270篇 |
1991年 | 289篇 |
1990年 | 235篇 |
1989年 | 232篇 |
1988年 | 206篇 |
1987年 | 161篇 |
1986年 | 183篇 |
1985年 | 189篇 |
1984年 | 189篇 |
1983年 | 97篇 |
1982年 | 146篇 |
1981年 | 153篇 |
1980年 | 138篇 |
1979年 | 100篇 |
1978年 | 81篇 |
1977年 | 65篇 |
1976年 | 58篇 |
1975年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Glaucoma is a leading cause of irreversible blindness. The use of topical eye drops to reduce intraocular pressure remains the mainstay treatment. These eye drops frequently contain preservatives designed to ensure sterility of the compound. A growing number of clinical and experimental studies report the detrimental effects of not only these preservatives but also the active pharmaceutical compounds on the ocular surface, with resultant tear film instability and dry eye disease. Herein, we critically appraise the published literature exploring the effects of preservatives and pharmaceutical compounds on the ocular surface. 相似文献
2.
3.
《The ocular surface》2020,18(1):108-113
PurposeAromatase inhibitors (AIs) limit the synthesis of oestrogen in peripheral tissues thus lowering levels of oestrogen. The primary aim was to evaluate whether women treated with AIs have altered dry eye symptoms and signs. A sub-aim was to investigate whether symptoms of dry eye in postmenopausal women were associated with symptoms of non-eye pain, ocular pain and self-rated pain perception.MethodsThis cross-sectional, observational, single visit study recruited 56 postmenopausal women (mean age 64.1 + 7.9 years) and 52 undergoing AI treatment (mean age 66.6 + 9.0). Ocular symptoms (OSDI, MGD14) and pain questionnaires (PSQ, OPAS) were administered and signs of dry eye and meibomian gland dysfunction were evaluated.ResultsAlmost half of each group reported dry eye symptoms, defined as OSDI>12 (48% control, 46% AI). The PSQ score was significantly higher in the AI group (p = 0.04). Neither frequency or severity of dry eye (or MGD) symptoms scores were significantly different between groups. In the AI group, meibomian gland expressibility score was worse (p = 0.003); there were no differences in any other signs. Higher OSDI scores were associated with higher OPAS eye-pain scores (r = 0.49, p < 0.001), but not OPAS non-eye pain (r = 0.09, p = 0.35). Pain perception (PSQ) showed a moderate positive association with OPAS eye-pain (r = 0.30, p = 0.003).ConclusionsIn this study elevated ocular symptoms were observed in both the AI treated and the untreated groups, with no difference between the groups. Women undergoing AI treatment for early stage breast cancer had worse meibum expressibility score and increased pain perception compared to an untreated group of women. 相似文献
4.
《Radiologia》2022,64(3):256-265
Breast cancer is the second most common cancer in Peruvian women. Due to limitations in national breast cancer screening programs, especially in rural areas, more than 50% of cases of breast cancer in Peru are diagnosed in advanced stages. In collaboration with a local clinic registered as a nongovernmental organization (CerviCusco), RAD-AID International aims to create a sustainable diagnostic structure to improve breast cancer screening in Cuzco. With the support of local, national, and international partners that have collaborated in analyzing radiological resources, raising awareness in the population, acquiring equipment, training clinical staff, and building referral networks, our teams of radiologists, included in the RAD-AID team, have participated in training CerviCusco staff in breast ultrasound, thus enabling additional training for radiology residents through a regulated international collaboration. 相似文献
5.
6.
Geneticists have, for years, understood the nature of genome‐wide association studies using common genomic variants. Recently, however, focus has shifted to the analysis of rare variants. This presents potential problems for researchers, as rare variants do not always behave in the same way common variants do, sometimes rendering decades of solid intuition moot. In this paper, we present examples of the differences between common and rare variants. We show why one must be significantly more careful about the origin of rare variants, and how failing to do so can lead to highly inflated type I error. We then explain how to best avoid such concerns with careful understanding and study design. Additionally, we demonstrate that a seemingly low error rate in next‐generation sequencing can dramatically impact the false‐positive rate for rare variants. This is due to the fact that rare variants are, by definition, seen infrequently, making it hard to distinguish between errors and real variants. Compounding this problem is the fact that the proportion of errors is likely to get worse, not better, with increasing sample size. One cannot simply scale their way up in order to solve this problem. Understanding these potential pitfalls is a key step in successfully identifying true associations between rare variants and diseases. 相似文献
7.
《Journal of the American College of Surgeons》2020,230(4):363-370
- Download : Download high-res image (207KB)
- Download : Download full-size image
8.
目的:探讨彩色多普勒超声诊断卵巢肿瘤蒂扭转的临床意义。方法方便选取2012―2015年该院收治的58例疑似卵巢肿瘤蒂扭转患者作为观察目标,入选病例均应用彩色多普勒超声进行检查,并将检查结果同术后病理检查结果进行比较。结果58例患者中,术后病理证实卵巢肿瘤蒂扭转者51例,彩色多普勒超声共确诊49例,检查准确率为96.1%;囊壁增厚、腹腔或盆腔积液、可见混合型团块是卵巢肿瘤蒂扭转的主要彩超表现。结论卵巢肿瘤蒂扭转应用彩色多普勒超声诊断,可显著提高诊断准确率,具有积极的临床使用和推广价值。 相似文献
9.
Breast Elastography: How to Perform and Integrate Into a “Best-Practice” Patient Treatment Algorithm
Breast elastography has been available for more than 15 years but is not widely incorporated into clinical practice. Many publications report extremely high accuracy for various breast elastographic techniques. However, results in the literature are extremely variable. This variability is most likely due to variations in technique, a relatively steep learning curve, and variability in methods between vendors. This article describes our protocol for performing breast elastography using both strain elastography and shear wave elastography, which produces high sensitivity and specificity. Additionally, we will describe the most commonly known false-positive and false-negative lesions as well as how to detect them. 相似文献
10.
《The ocular surface》2020,18(4):657-662
PurposeTo determine if meibomian gland architecture in a pediatric population is impacted by body mass index (BMI).MethodsProspective evaluation of 175 eyes of 175 pediatric patients from two clinics. Demographic and clinical information were reviewed. Symptoms of dry eye were assessed with the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire. Meibography was performed and grading of images was performed by a masked rater using a previously validated 5-point meiboscale (0–4) for gland atrophy and a 3-point score (0–2) for gland tortuosity.Results175 eyes of 175 participants aged 4–17 years (11.6 ± 3.7 years) were imaged. The mean meiboscore was 0.82 ± 0.94 (range 0–4) and the mean gland tortuosity score was 0.53 ± 0.70 (range 0–2). Ninety-six patients (56%) showed evidence of gland atrophy (meiboscore greater than 0) and the majority of patients (n=50, 29%) had a gland tortuosity score of 1. The mean BMI was 20.5 ± 4.86 kg/m2 with 39.4% of patients (n = 69) above the 85th percentile. BMI percentile was not found to be a significant predictor of a meiboscore greater than 0 (odds ratio (OR) 1.004 95% confidence interval (CI) (0.99–1.10, p = 0.41). However, BMI percentile was found to be a significant predictor of gland tortuosity score (OR 1.01 95% CI (1.00–1.02), p = 0.02). Patients with BMI percentiles between 41 and 60 were 3.79 times more likely to have a gland tortuosity score of greater than 0 than patients with BMI percentiles between 0 and 20 (OR 3.789 CI (1.17–12.24)). No significant associations were found between age, race, or sex and meiboscore or tortuosity. There was a trend towards reduction in lipid layer thickness with increasing BMI percentile (p = 0.028, r2 = 0.04).ConclusionIn this pediatric population, there was an association between meibomian gland tortuosity and higher percentiles of BMI. Future studies are needed to elucidate the pathogenesis of meibomian gland tortuosity and atrophy in pediatric patients. 相似文献