全文获取类型
收费全文 | 3080篇 |
免费 | 242篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 90篇 |
妇产科学 | 49篇 |
基础医学 | 314篇 |
口腔科学 | 46篇 |
临床医学 | 293篇 |
内科学 | 993篇 |
皮肤病学 | 28篇 |
神经病学 | 220篇 |
特种医学 | 91篇 |
外科学 | 604篇 |
综合类 | 35篇 |
一般理论 | 1篇 |
预防医学 | 124篇 |
眼科学 | 41篇 |
药学 | 137篇 |
中国医学 | 1篇 |
肿瘤学 | 244篇 |
出版年
2023年 | 28篇 |
2022年 | 53篇 |
2021年 | 101篇 |
2020年 | 51篇 |
2019年 | 79篇 |
2018年 | 122篇 |
2017年 | 82篇 |
2016年 | 83篇 |
2015年 | 68篇 |
2014年 | 108篇 |
2013年 | 129篇 |
2012年 | 206篇 |
2011年 | 204篇 |
2010年 | 138篇 |
2009年 | 105篇 |
2008年 | 181篇 |
2007年 | 199篇 |
2006年 | 167篇 |
2005年 | 154篇 |
2004年 | 143篇 |
2003年 | 122篇 |
2002年 | 125篇 |
2001年 | 74篇 |
2000年 | 55篇 |
1999年 | 54篇 |
1998年 | 34篇 |
1997年 | 24篇 |
1996年 | 15篇 |
1995年 | 14篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1992年 | 50篇 |
1991年 | 42篇 |
1990年 | 49篇 |
1989年 | 35篇 |
1988年 | 32篇 |
1987年 | 19篇 |
1986年 | 15篇 |
1985年 | 15篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1979年 | 12篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1974年 | 10篇 |
1973年 | 9篇 |
1972年 | 12篇 |
1970年 | 8篇 |
1969年 | 13篇 |
排序方式: 共有3336条查询结果,搜索用时 15 毫秒
1.
2.
Mohammed Al Essa Abdulrahman Alissa Abdalrhman Alanizi Rami Bustami Feras Almogbel Omar Alzuwayed Meshari Abo Moti Nouf Alsadoun Wasmiyah Alshammari Abdulkareem Albekairy Shmeylan Al Harbi Mohammed Alhokail Jawaher Gramish 《Saudi Pharmaceutical Journal》2019,27(1):138-144
Background
Herbal medicine has been widely utilized by pregnant women despite the limited available evidence regarding the safety and efficacy of that practice. The current available studies, from different countries, estimated that the use of herbal medicine during pregnancy range from 7% up to 96%. The aim of this study is to determine the prevalence, attitude, source of information, and reasoning behind the use of herbal medicine among pregnant women in Saudia Arabia.Methods
A cross-sectional study conducted using a convenience sample including pregnant women who visited the obstetric clinics at King Abdulaziz Medical City in Riyadh, Saudi Arabia. A survey was administered in order to evaluate the prevalence and perception toward herbal medicine use among pregnant women in Saudi Arabia.Results
A total of 297 pregnant women completed the survey. The results showed that 56% of the respondents have used some type of herbal medicine during their pregnancy. Olive oil was utilized in 26% of the respondents followed by cumin 20% and garlic 15%. In addition, 37% of the respondents used herbal medicine by their own initiative, while 33% and 12% used herbal medicine based on recommendations from their families and friends, respectively. Furthermore, 19% of the respondents reported a positive attitude toward herbal medicine use during pregnancy. In addition, the percentage of women with positive attitude was marginally higher among respondents with lower educational level.Conclusion
The prevalence of using herbal medicine is considerably high among pregnant women in Saudi Arabia. Unfortunately, the majority of the users relied on informal sources to use herbal medicine during pregnancy. 相似文献3.
Characterization of Left Atrial Mechanics in Hypertrophic Cardiomyopathy and Essential Hypertension Using Vector Velocity Imaging
下载免费PDF全文
![点击此处可从《Echocardiography (Mount Kisco, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
4.
Hitoshi Ogino Nongchana Klangsuk Wu Jin Christopher T. Bowles Magdi H. Yacoub 《Artificial organs》1995,19(6):525-534
Abstract: The dependence of transient pressure characteristics of a ventricular assist device (VAD) on the compliance of its housing and cannulas was investigated in a mock circulation. The peak rate of change of pressure ( dP/dt max ) values was greater in the cannulas than other compartments and was associated with valve closure-induced pressure oscillations. When cannula compliance was increased from 0.0057 to 0.0129 cm3 /mm Hg, these values decreased by ˜20%, and outflow cannula pressure oscillation frequency decreased from 17.5 Hz by 35%. This trend was also apparent in the inflow. A VAD housing compliance increase from 0.0162 to 0.0483 cm3 /mm Hg caused a dP/dt max decrease of 30% in both the blood chamber and the outflow cannula. The effect of this change on the inflow was weaker implying that housing absorbs the energy associated with outflow deceleration more effectively than the inflow. These findings suggest that increasing VAD housing and cannulas compliance can improve hydrodynamic performance. 相似文献
5.
Selection for donor-specific cytotoxic T lymphocytes within the allografted human heart. 总被引:3,自引:0,他引:3
Lymphocytes were cultured from cardiac biopsies following heart transplantation using interleukin-2-conditioned medium. Using the technique of limiting dilution analysis the frequency of donor specific cytotoxic T lymphocytes was measured in cells cultured from biopsies and compared with that in peripheral blood lymphocytes taken at the same time as the biopsy. The graft cell population showed a considerably higher frequency of donor-specific CTL when compared with the PBL. CTL frequencies in the graft cells were always higher against the donor than against third-party cells. These data demonstrate that there was either selective sequestration or selective expansion of donor-reactive T cells in the heart following cardiac transplantation. These results emphasize the need to investigate more closely the events occurring in the heart, and may explain the lack of specificity and sensitivity in immune monitoring (IM) or cytoimmune monitoring (CIM) seen in many centers. 相似文献
6.
Hilary Eadon Marlene Rose Richard O'Neill Neil Leaver Magdi Yacoub 《Transplant international》1995,8(1):35-40
Pharmacokinetic profiles were obtained for 16 heart or lung recipients following the administration of identical doses of cyclosporin as oral solution and capsules on consecutive days. A comparison of pharmacokinetic parameters (AUC, Cmax, Cmin and tmax) showed that there were no significant differences between the two formulations except for the tmax, which was significantly longer for the capsules. The mean variation in day-to-day trough levels produced by the two different forms was 25.6%. A retrospective study was carried out of consecutive cyclosporin levels in patients at steady state on oral solution. The mean variation in day-to-day trough levels was 32.3%. This was not significantly different from the variation in consecutive trough levels seen in the oral solution/capsule comparison. This study shows that cyclosporin capsules can be substituted for oral solution without causing acute changes in cyclosporin blood levels, and that the pharmacokinetics of the two formulations are similar.This work was carried out in partial fulfillment of the requirements for the Master of Science Degree in Clinical Pharmacy, University of London 相似文献
7.
8.
ESTS guidelines for intraoperative lymph node staging in non-small cell lung cancer. 总被引:3,自引:0,他引:3
Didier Lardinois Paul De Leyn Paul Van Schil Ramon Rami Porta David Waller Bernward Passlick Marcin Zielinski Toni Lerut Walter Weder 《European journal of cardio-thoracic surgery》2006,30(5):787-792
The European Society of Thoracic Surgeons (ESTS) organized a workshop dealing with lymph node staging in non-small cell lung cancer. The objective of this workshop was to develop guidelines for definitions and the surgical procedures of intraoperative lymph node staging, and the pathologic evaluation of resected lymph nodes in patients with non-small cell lung cancer (NSCLC). Relevant peer-reviewed publications on the subjects, the experience of the participants, and the opinion of the ESTS members contributing on line, were used to reach a consensus. Systematic nodal dissection is recommended in all cases to ensure complete resection. Lobe-specific systematic nodal dissection is acceptable for peripheral squamous T1 tumors, if hilar and interlobar nodes are negative on frozen section studies; it implies removal of, at least, three hilar and interlobar nodes and three mediastinal nodes from three stations in which the subcarinal is always included. Selected lymph node biopsies and sampling are justified to prove nodal involvement when resection is not possible. Pathologic evaluation includes all lymph nodes resected separately and those remaining in the lung specimen. Sections are done at the site of gross abnormalities. If macroscopic inspection does not detect any abnormal site, 2-mm slices of the nodes in the longitudinal plane are recommended. Routine search for micrometastases or isolated tumor cells in hematoxylin-eosin negative nodes would be desirable. Randomized controlled trials to evaluate adjuvant therapies for patients with these conditions are recommended. The adherence to these guidelines will standardize the intraoperative lymph node staging and pathologic evaluation, and improve pathologic staging, which will help decide on the best adjuvant therapy. 相似文献
9.
RASER: a new ultrafast magnetic resonance imaging method. 总被引:1,自引:0,他引:1
Ryan Chamberlain Jang-Yeon Park Curt Corum Essa Yacoub Kamil Ugurbil Clifford R Jack Michael Garwood 《Magnetic resonance in medicine》2007,58(4):794-799
A new MRI method is described to acquire a T(2)-weighted image from a single slice in a single shot. The technique is based on rapid acquisition by sequential excitation and refocusing (RASER). RASER avoids relaxation-related blurring because the magnetization is sequentially refocused in a manner that effectively creates a series of spin echoes with a constant echo time. RASER uses the quadratic phase produced by a frequency-swept chirp pulse to time-encode one dimension of the image. In another implementation the pulse can be used to excite multiple slices with phase-encoding and frequency-encoding in the other two dimensions. The RASER imaging sequence is presented along with single-shot and multislice images, and is compared to conventional spin-echo and echo-planar imaging sequences. A theoretical and empirical analysis of the spatial resolution is presented, and factors in choosing the spatial resolution for different applications are discussed. RASER produces high-quality single-shot images that are expected to be advantageous for a wide range of applications. 相似文献
10.
Reproducible model of post-infarction left ventricular dysfunction: haemodynamic characterization by conductance catheter. 总被引:4,自引:0,他引:4
A K Hasnat Enno T van der Velde Jimmy K F Hon Magdi H Yacoub 《European journal of cardio-thoracic surgery》2003,24(1):98-104
OBJECTIVE: The understanding of pathophysiology and cellular mechanisms of chronic heart failure requires the creation of appropriate and accurately characterized animal models, thus enabling meaningful evaluation of evolving medical and surgical therapies. METHODS: The left anterior descending and its diagonal branch were ligated in 12 sheep to induce left ventricular dysfunction. RESULTS: Study of left ventricular pressure-volume loops 3 months post-operatively showed a significant deterioration of both systolic and diastolic indexes of left ventricular function. The left ventricular end-diastolic pressure increased from 3+/-1 to 7+/-1 mmHg (P<0.001) along with a substantial increase in end-diastolic volume from 78+/-8 to 121+/-6 ml (P=0.002) and a significant decrease in cardiac output from 2+/-0.2 to 1.5+/-0.2 l/min (P=0.001). The left ventricular end-systolic pressure-volume relationship deteriorated from 2.7+/-0.37 to 0.7+/-0.16 mmHg/ml (P=0.0002) along with a significant reduction in the pre-load recruitable stroke work (P=0.001). The ejection fraction decreased from 34+/-2% to 16+/-4% (P<0.001) with a significant decrease in +dp/dt and -dp/dt (P=0.009). The mean systemic blood pressure, however, was maintained due to a substantial increase in the systemic vascular resistance (P=0.007). CONCLUSION: This study describes a reproducible large animal model of left ventricular dysfunction. This model is potentially useful to study the pathogenesis of remodelling, surgical management of heart failure and development of novel treatment strategies. 相似文献