全文获取类型
收费全文 | 8780篇 |
免费 | 576篇 |
国内免费 | 139篇 |
专业分类
耳鼻咽喉 | 30篇 |
儿科学 | 115篇 |
妇产科学 | 79篇 |
基础医学 | 1078篇 |
口腔科学 | 329篇 |
临床医学 | 1101篇 |
内科学 | 1159篇 |
皮肤病学 | 64篇 |
神经病学 | 744篇 |
特种医学 | 226篇 |
外科学 | 1109篇 |
综合类 | 605篇 |
现状与发展 | 3篇 |
一般理论 | 2篇 |
预防医学 | 1305篇 |
眼科学 | 69篇 |
药学 | 1142篇 |
1篇 | |
中国医学 | 151篇 |
肿瘤学 | 183篇 |
出版年
2024年 | 15篇 |
2023年 | 177篇 |
2022年 | 247篇 |
2021年 | 386篇 |
2020年 | 347篇 |
2019年 | 327篇 |
2018年 | 352篇 |
2017年 | 295篇 |
2016年 | 285篇 |
2015年 | 352篇 |
2014年 | 520篇 |
2013年 | 854篇 |
2012年 | 468篇 |
2011年 | 451篇 |
2010年 | 392篇 |
2009年 | 418篇 |
2008年 | 418篇 |
2007年 | 385篇 |
2006年 | 333篇 |
2005年 | 312篇 |
2004年 | 271篇 |
2003年 | 199篇 |
2002年 | 154篇 |
2001年 | 99篇 |
2000年 | 111篇 |
1999年 | 97篇 |
1998年 | 105篇 |
1997年 | 90篇 |
1996年 | 77篇 |
1995年 | 83篇 |
1994年 | 67篇 |
1993年 | 79篇 |
1992年 | 61篇 |
1991年 | 72篇 |
1990年 | 72篇 |
1989年 | 67篇 |
1988年 | 63篇 |
1987年 | 57篇 |
1986年 | 46篇 |
1985年 | 43篇 |
1984年 | 50篇 |
1983年 | 31篇 |
1982年 | 44篇 |
1981年 | 21篇 |
1980年 | 46篇 |
1979年 | 17篇 |
1978年 | 10篇 |
1977年 | 11篇 |
1976年 | 7篇 |
1975年 | 7篇 |
排序方式: 共有9495条查询结果,搜索用时 15 毫秒
31.
应用修正正交分段线性函数的时滞和反向特性,推导出求解时滞系统和卷积的公式。数字仿真表明,它具有计算简单,精度高的优点。 相似文献
32.
Mahmut Koç Ömer Yoldaş Yusuf Alper Kılıç Erdal Göçmen Tamer Ertan Hayrettin Dizen Mesut Tez 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2007,392(5):581-585
Background and aims The aim of this study is to evaluate the predictive accuracy of different scoring systems on surgery for perforated peptic
ulcer referred to an academic department of general surgery in a tertiary reference center.
Patients and methods Seventy-five consecutive patients (Male/female ratio = 64:11; mean age, 44 years; range, 16–85) with perforated peptic ulcer
disease were investigated. Disease severity scores and mortality predictions were calculated using the collected data during
admission. Discrimination and calibration characteristics of each system, namely, the acute physiology and chronic health
evaluation II and III, the simplified acute physiology score II, and the mortality probability models (MPM) II, were determined
by using the area under receiver operating characteristics curve and the Hosmer–Lemeshow goodness-of-fit test, respectively.
Results Among the 75 patients included, there were eight (10.6%) mortalities. All systems had a reliable power of discrimination and
calibration. Among the systems tested, MPM II was the best performing as far as discrimination and calibration characteristics
were considered. The parameters of MPM II system that were related to systemic perfusion of the patient were significantly
positive in patients who died compared to those who survived.
Conclusions MPM II that predicted mortality at admission is better than the other systems in predicting mortality. Results also indicate
the importance of maintenance of systemic perfusion of the patient at the early phases of peptic ulcer perforation. 相似文献
33.
This study uses the Taiwan Healthcare Indicator Series (THIS) system as an example to examine which determinants would improve
performance by sharing indicators from a management perspective. This study population included all 227 hospitals participating
in the THIS system in 2006. A structured questionnaire was sent to the director who was responsible for the THIS system via
electronic mail. A total of 111 responses were returned by February 10, 2006. Questions included current implementation and
impacts of the system. Hierarchical regression models were performed to identify which variables were significantly associated
with performance improvement, adjusted for hospital characteristics. Four variables significantly associated with implementing
the THIS system to improve performance were ‘senior management support,’ ‘benchmarking,’ ‘making departments improve the underperforming
indicators and report the improvement results in performance management meetings,’ and ‘integration with the National Health
Insurance payment regulations’. This study contributes substantially to the evidence base about what works to improve performance
by information sharing. Although information sharing is the basis of efforts to improve performance, senior management support
and how to effectively apply the information are the most important determinants of performance enhancement. 相似文献
34.
Paolo R. Salvalaggio Katie Neighbors Susan Kelly Karan M. Emerick Kishore Iyer Riccardo A. Superina Peter F. Whitington Estella M. Alonso 《American journal of transplantation》2005,5(8):1868-1874
The Pediatric End-Stage Liver Disease (PELD) score was designed to reduce subjectivity in liver allocation and to advantage patients with a higher probability of waiting list mortality. The aims of this study were to determine the impact of PELD implementation for children with chronic liver disease and to assess whether PELD met its goal of standardization of liver allocation for children. This study used data reported to the United Network for Organ Sharing (UNOS) registry for children with chronic liver disease receiving primary cadaveric liver transplant between January 2000 and December 2001 (pre-PELD) and March 2002 and July 2003 (PELD). PELD reduced the percentage of children transplanted while in an intensive care unit and as status 1. A calculated PELD score was used for allocation in only 52% of recipients. Thirty percent were status 1 at transplant and PELD scores granted by exception were used for allocation in 18% of patients. There was regional variation in PELD score at allocation and use of exception scores with a significant relationship between PELD score and percentage of exception cases. Regional variation suggests that PELD has not resulted in standardization of listing practices in pediatric liver transplantation. 相似文献
35.
Van Buskirk Glenn A. González Mario A. Shah Vinod P. Barnhardt Scott Barrett Colin Berge Stephen Cleary Gary Chan Keith Flynn Gordon Foster Thomas Gale Robert Garrison Raymond Gochnour Scott Gotto Amanda Govil Sharad Gray Vivian A. Hammar James Harder Samuel Hoiberg Charles Hussain Ajaz Karp Carol Llanos Hector Mantelle Juan Noonan Patrick Swanson David Zerbe Horst 《Pharmaceutical research》1997,14(7):848-852
Pharmaceutical Research - 相似文献
36.
The ripple-free deadbeat control problem for SISO plants subjected to arbitrary reference signals is considered. The trade-off between the settling time and the integral square error between the system output and reference signal is investigated. Given a specific order of the controller, it is shown how to design an optimal ripple-free deadbeat controller. An illustrative example is presented to show the feasibility of the proposed algorithm. 相似文献
37.
This paper considers a pole assignment problem to cluster all poles of a closed-loop system into some specified regions by introducing the complex state for systems having an isotropic property and by using the Riccati equation. The algebraic relations for the distribution of the eigenvalues of a complex matrix are used in order to cluster the poles into specified regions, which guarantees the relative stability margin, e.g. uniform damping or uniform damping ratio. The proposed scheme is essentially a combination of the pole assignment approach and linear quadratic design, taking the advantages of both. A block modal control method—an extension of recursive pole assignment—is also developed for the vibration control of rotating systems by clustering the forward and backward modes in order. Vibration control simulations with an isotropic rotor—bearing system, a magnetic bearing system and a rotating circular disc are treated in order to demonstrate the advantages of the proposed method. 相似文献
38.
基于Lyapnuov泛函方法,研究了满足匹配条件的不确定性时滞系统的鲁棒稳定性及具有稳定度β〉0鲁棒稳定性,给出了已有结果不能推出的新判据。这些新判据对已有结果难以使用的情况下也可有是有效的,或有时减少了已有结果的保守性。 相似文献
39.
Background : In order to find the most useful computerized auditing system for the needs of the QE II Hospital surgical department three surgical auditing software programs were assessed. Methods : The Otago University Surgical Auditing Program, the Australian Surgical Auditing Program, and RACS-Audit were trialled for a period of 1 month each. The software programs were evaluated to find the time requirements for data entry, the level of surgical knowledge needed for effective audit information entry, and the perceived usefulness of the generated reports. Results : It was found that the Otago University program best suited the needs of the department. This system was designed for use in a hospital environment with multiple users. The method of data collection was simple and rapid. Entry of data into the program was logical, well structured and able to be performed by both junior medical staff and clerical staff. Reports generated by this system included information in an appropriate format for the departments' morbidity and mortality meetings. Conclusion : Personal computers are an ideal tool for the undertaking of surgical audit. Software programs are designed for different uses and should be critically assessed to ensure that the method of data entry, the time involved, and the reports generated enable an efficient and effective audit to be carried out. 相似文献
40.