全文获取类型
收费全文 | 48625篇 |
免费 | 4708篇 |
国内免费 | 1458篇 |
专业分类
耳鼻咽喉 | 523篇 |
儿科学 | 445篇 |
妇产科学 | 304篇 |
基础医学 | 4698篇 |
口腔科学 | 1290篇 |
临床医学 | 5638篇 |
内科学 | 3057篇 |
皮肤病学 | 412篇 |
神经病学 | 2529篇 |
特种医学 | 2361篇 |
外国民族医学 | 1篇 |
外科学 | 3346篇 |
综合类 | 9195篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 5991篇 |
眼科学 | 884篇 |
药学 | 7319篇 |
180篇 | |
中国医学 | 5606篇 |
肿瘤学 | 1007篇 |
出版年
2024年 | 83篇 |
2023年 | 804篇 |
2022年 | 1283篇 |
2021年 | 2133篇 |
2020年 | 2029篇 |
2019年 | 1437篇 |
2018年 | 1435篇 |
2017年 | 1730篇 |
2016年 | 1783篇 |
2015年 | 1829篇 |
2014年 | 3421篇 |
2013年 | 3620篇 |
2012年 | 3247篇 |
2011年 | 3521篇 |
2010年 | 2676篇 |
2009年 | 2319篇 |
2008年 | 2367篇 |
2007年 | 2581篇 |
2006年 | 2070篇 |
2005年 | 1814篇 |
2004年 | 1546篇 |
2003年 | 1321篇 |
2002年 | 1087篇 |
2001年 | 958篇 |
2000年 | 796篇 |
1999年 | 701篇 |
1998年 | 594篇 |
1997年 | 501篇 |
1996年 | 508篇 |
1995年 | 516篇 |
1994年 | 471篇 |
1993年 | 417篇 |
1992年 | 381篇 |
1991年 | 337篇 |
1990年 | 293篇 |
1989年 | 285篇 |
1988年 | 263篇 |
1987年 | 245篇 |
1986年 | 207篇 |
1985年 | 260篇 |
1984年 | 174篇 |
1983年 | 127篇 |
1982年 | 148篇 |
1981年 | 96篇 |
1980年 | 91篇 |
1979年 | 56篇 |
1978年 | 62篇 |
1977年 | 43篇 |
1976年 | 44篇 |
1974年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Guo-Quan Shi Huajun Zhu & Zhen-Guo Yan 《Communications In Computational Physics》2022,31(4):1215-1241
A priori subcell limiting approach is developed for high-order flux reconstruction/correction procedure via reconstruction (FR/CPR) methods on two-dimensional unstructured quadrilateral meshes. Firstly, a modified indicator based on
modal energy coefficients is proposed to detect troubled cells, where discontinuities
exist. Then, troubled cells are decomposed into nonuniform subcells and each subcell has one solution point. A second-order finite difference shock-capturing scheme
based on nonuniform nonlinear weighted (NNW) interpolation is constructed to perform the calculation on troubled cells while smooth cells are calculated by the CPR
method. Numerical investigations show that the proposed subcell limiting strategy on
unstructured quadrilateral meshes is robust in shock-capturing. 相似文献
2.
《European journal of surgical oncology》2022,48(5):1062-1067
BackgroundSurgical resection is recommended for patients with resectable acinar cell carcinoma (ACC). The aim of this study was to investigate the clinical characteristics and surgical outcomes of resectable ACC in comparison to pancreatic ductal adenocarcinoma (PDAC).MethodA retrospective analysis was performed on all patients who consecutively underwent radical resection with pathologically confirmed ACC and PDAC from December 2011 to December 2018. Clinicopathologic characteristics and follow-up information were analyzed. A 1:3 propensity score matching (PSM) method was used to minimize the bias between ACC and PDAC.ResultsA total of 26 patients with ACC and 1351 with PDAC were included. Compared to PDAC, ACC tended to be larger (4.5 vs. 3.0 cm; p < 0.001) and more frequently located in the pancreatic body/tail (61.5% vs. 36.6%, p = 0.009), with lower total bilirubin levels, lower neutrophil lymphocyte ratio (NLR) levels and lower carbohydrate antigen 19-9 (CA19-9) levels and carcinoembryonic antigen (CEA) levels. There was no difference in postoperative morbidities in patients with ACC and PDAC. The median OS and RFS were longer in ACC when compared to PDAC (OS: 43.5 mo vs. 19.0 mo, p = 0.004; RFS: 24.5 mo vs. 11.6 mo, p = 0.023). After the 1:3 PSM, ACC remained to be a better histological type for OS (p = 0.024), but had comparable RFS with PDAC (p = 0.164).ConclusionPatients with ACC after radical resection had better OS than that with PDAC. However, ACC is also an aggressive tumor with a similar trend of RFS with PDAC after the matching, necessitating the multidisciplinary treatment for resectable ACC disease. 相似文献
3.
4.
《Pediatric Dental Journal》2022,32(2):87-93
ObjectivesThe study aimed to estimate the age of Iraqi children and young adults based on the third molar development to establish Iraqi reference material for orthodontic and forensic purposes, and to investigate the correlation between the estimated and chronological age.MethodsA retrospective analysis of digital orthopantographs of 1515 patients of Iraqi origin, aged from 6 to 25 years was conducted, and the developmental status of the mandibular right third molar for each patient was evaluated using Demirjian et al.’s method. Statistical analysis was carried out using “Mann-Whitney U-test” between genders. The linear regression analysis was performed to obtain “regression formulas” for dental age calculation with chronologic age.ResultsNo statistically significant differences were observed between Iraqi males and females at any age. The median of male and female age of initial calcification of the cuspal tips for mandibular third molars was 9 years, whereas 14 years was the median of age for both genders when the crown was completed. All mandibular right third molars have a complete root formation with apex closure at a median of male and female age 22 years.ConclusionsThe use of Demirjian et al.’s method was appropriate as a reliable age indicator for Iraqi population. A strong correlation was observed between these stages and chronological age. Consequently, reference data have been established for mandibular third molar development in Iraqi population. 相似文献
5.
目的 基于红外热成像技术探讨“扶正温阳法”对阳虚质的影响,探讨阳虚质者红外热图的共性规律,分析判断“扶正温阳法”干预阳虚质人群的疗效。方法 纳入30例阳虚质患者给予益气温阳药物在大椎、肾俞(双侧)、命门等进行穴位贴敷,分别在干预前后运用红外热成像技术测定督脉、腰部、腹部、双手及双足局部温度的变化。结果 干预后阳虚体质患者的督脉、腰部、腹部、双手、双足温度均升高(P<0.05),阳虚体质局部温度得以改善。结论 本研究发现“扶正温阳法”可诱发循经热传导现象,通过调节热能代谢而起到调治阳虚体质的作用,红外热成像技术可用来辅助评价阳虚质的治疗效果,对临床指导制定阳虚质人群的干预方案疗效判定具有指导意义。 相似文献
6.
以“七麦数据”网站收录的中医移动医疗App作为研究对象,采用网络调查法和文献分析法,根据“七麦数据”对移动医疗App的分类,结合中医移动医疗App的信息服务内容和特点,将筛选出的中医移动医疗App划分为医疗健康类、中医养生类、知识传播类、全面综合类,并根据“七麦数据”网站中对各类中医移动医疗App的打分及累计下载量筛选出最具代表性的12款中医移动医疗App,从全面性、人性化、安全性、实用性4个一级指标和40个二级指标对其信息服务现状进行评价,指出当前中医移动医疗App信息服务存在的问题并提出建议。 相似文献
7.
High Order Finite Difference Hermite WENO Fixed-Point Fast Sweeping Method for Static Hamilton-Jacobi Equations 下载免费PDF全文
In this paper, we combine the nonlinear HWENO reconstruction in [43] and
the fixed-point iteration with Gauss-Seidel fast sweeping strategy, to solve the static
Hamilton-Jacobi equations in a novel HWENO framework recently developed in [22].
The proposed HWENO frameworks enjoys several advantages. First, compared with
the traditional HWENO framework, the proposed methods do not need to introduce
additional auxiliary equations to update the derivatives of the unknown function $\phi$.
They are now computed from the current value of $\phi$ and the previous spatial derivatives of $\phi$. This approach saves the computational storage and CPU time, which greatly
improves the computational efficiency of the traditional HWENO scheme. In addition,
compared with the traditional WENO method, reconstruction stencil of the HWENO
methods becomes more compact, their boundary treatment is simpler, and the numerical errors are smaller on the same mesh. Second, the fixed-point fast sweeping method
is used to update the numerical approximation. It is an explicit method and does
not involve the inverse operation of nonlinear Hamiltonian, therefore any Hamilton-Jacobi equations with complex Hamiltonian can be solved easily. It also resolves some
known issues, including that the iterative number is very sensitive to the parameter $ε$ used in the nonlinear weights, as observed in previous studies. Finally, to further
reduce the computational cost, a hybrid strategy is also presented. Extensive numerical experiments are performed on two-dimensional problems, which demonstrate the
good performance of the proposed fixed-point fast sweeping HWENO methods. 相似文献
8.
9.
《Journal of Radiology Nursing》2022,41(3):170-179
BackgroundDespite indications for the removal of temporary inferior vena cava (IVC) filters, many filters are unintentionally left in place, predisposing patients to adverse outcomes.ObjectiveThis quality improvement study set out to determine the impact of an IVC filter retrieval protocol on filter retrieval rates and patients lost to follow-up for patients who had undergone placement of a temporary IVC filter.MethodsFollowing a quasi-experimental design, data of all consecutive patients who underwent insertion of a temporary IVC filter for a period of 24-month preprotocol and 12-month postprotocol were compared.ResultsFilter retrieval rates of eligible filters increased from 64.2% to 100%; patients lost to follow-up decreased from 35.9% to 0% (p < .01, both outcomes).ConclusionAdoption of a comprehensive IVC filter protocol by the service that implants these devices can improve filter retrieval rates and decrease patients being lost to follow-up. 相似文献
10.