全文获取类型
收费全文 | 8367篇 |
免费 | 489篇 |
国内免费 | 41篇 |
专业分类
耳鼻咽喉 | 94篇 |
儿科学 | 308篇 |
妇产科学 | 271篇 |
基础医学 | 781篇 |
口腔科学 | 286篇 |
临床医学 | 796篇 |
内科学 | 1958篇 |
皮肤病学 | 246篇 |
神经病学 | 627篇 |
特种医学 | 312篇 |
外科学 | 1476篇 |
综合类 | 108篇 |
一般理论 | 7篇 |
预防医学 | 464篇 |
眼科学 | 199篇 |
药学 | 464篇 |
中国医学 | 36篇 |
肿瘤学 | 464篇 |
出版年
2024年 | 12篇 |
2023年 | 110篇 |
2022年 | 184篇 |
2021年 | 397篇 |
2020年 | 259篇 |
2019年 | 355篇 |
2018年 | 342篇 |
2017年 | 253篇 |
2016年 | 266篇 |
2015年 | 275篇 |
2014年 | 388篇 |
2013年 | 411篇 |
2012年 | 718篇 |
2011年 | 705篇 |
2010年 | 406篇 |
2009年 | 351篇 |
2008年 | 507篇 |
2007年 | 525篇 |
2006年 | 429篇 |
2005年 | 392篇 |
2004年 | 326篇 |
2003年 | 305篇 |
2002年 | 255篇 |
2001年 | 82篇 |
2000年 | 68篇 |
1999年 | 65篇 |
1998年 | 37篇 |
1997年 | 41篇 |
1996年 | 35篇 |
1995年 | 24篇 |
1994年 | 18篇 |
1993年 | 28篇 |
1992年 | 21篇 |
1991年 | 29篇 |
1990年 | 29篇 |
1989年 | 15篇 |
1988年 | 24篇 |
1987年 | 19篇 |
1986年 | 16篇 |
1985年 | 27篇 |
1984年 | 26篇 |
1983年 | 19篇 |
1982年 | 11篇 |
1981年 | 12篇 |
1980年 | 7篇 |
1979年 | 11篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1975年 | 8篇 |
1974年 | 9篇 |
排序方式: 共有8897条查询结果,搜索用时 31 毫秒
1.
Hommes Franziska Mohsenpour Amir Kropff Dana Pilgram Lisa Matusall Svenja von Philipsborn Peter Sell Kerstin 《Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz》2022,65(1):96-106
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Akteure der öffentlichen Gesundheit (Public Health) tragen wesentlich zu Gesundheitsschutz, -förderung und... 相似文献
2.
Afsaneh Amouei Mahmood Moosazadeh Tooran Nayeri chegeni Shahabeddin Sarvi Azadeh Mizani Mehdi Pourasghar Saeed Hosseini Teshnizi Zahra Hosseininejad Samira Dodangeh Abdolsattar Pagheh Amir Hossein Pourmand Ahmad Daryani 《Transboundary and Emerging Diseases》2020,67(5):1847-1860
The World Health Organization has reported an annual global suicide rate of 14.5 per 100,000 people. On the other hand, it is estimated that approximately one‐third of the global population are infected with Toxoplasma gondii (T. gondii) parasite. It is widely assumed that microbial pathogens, such as T. gondii, are probably associated with affective and behavioural modulation. The present article aimed to assess the proposed role of toxoplasmosis in raising the risk of suicidal ideation (SI) and suicide attempts (SA) using the available epidemiological data. Seven major electronic databases and the Internet search engine Google were searched for all the studies published between the 1st of January 1950 and 31st of October 2019. The heterogeneity and the risk of bias within and across studies were assessed. Following data extraction, pooled odds ratios (ORs) with 95% confidence interval (CI) across studies were calculated using the random‐effects models. A total number of 9,696 articles were screened and 27 studies were regarded as eligible in our systematic review (SI with five papers and 22 papers on SA). A significant association was detected between antibodies against T. gondii with TA (ORs = 1.57; 95% confidence interval [CI] 1.23–2.00, p = .000). Exploration of the association between T. gondii and SA yielded a positive effect of seropositivity for IgG antibodies but not IgM. Despite the limited number of studies, a statistical association was detected between suicidal behaviours and infection with latent T. gondii. 相似文献
3.
Conjunctival flap advancement with or without scleral graft for hypotony maculopathy after trabeculectomy 下载免费PDF全文
AIM: To introduce a novel technique for transscleral fixation of the PC-IOL that requires no sutures on the IOL haptics. METHODS: Instead of suturing polypropylene onto the IOL haptics, the method simply winds the thread on the haptics. Fifteen eyes of 15 patients underwent this technique and were followed up for more than 18 months. Surgical outcomes and post-operative complications were evaluated and compared with those of the conventional transscleral fixation method. RESULTS: Postoperative cylinder was significantly lower in the thread winding group than in the conventional transscleral fixation method group (-1.02±0.46 diopters vs -1.57±0.77 diopters; P=0.01). Further, no postoperative complications, such as optic capture, IOL dislocation, and hyphema, were detected in the thread winding group. CONCLUSION: We believe that our thread winding technique is better than previously reported methods because it is simple, mechanically stable, and free from suture-related complications. 相似文献
4.
Bagher Larijani Alireza Moayyeri Abbas Ali Keshtkar Arash Hossein-Nezhad Akbar Soltani Amir Bahrami Gholam Hossein Omrani Reza Rajabian Iraj Nabipour 《Journal of clinical densitometry》2006,9(3):367-374
Osteoporosis is a major public health problem in the Western countries and is projected to have a similar impact in the Middle East. It has been suggested that peak bone mineral density (BMD), a major determinant of osteoporotic fractures later in life, may be lower in this part of the world compared with the Western world. The purpose of the Iranian Multicenter Osteoporosis Study was to determine peak bone mass in a randomly chosen sample of healthy Iranian subjects. A total of 5201 participants (2340 males, mean age 42.7+/-13.8) were recruited based on randomized clustered sampling from all regions of five major cities across the country. In women, peak lumbar BMD (1.182+/-0.127 g/cm2) occurred in the 29- to 33-yr age group, whereas peak total femur BMD (1.006+/-0.126 g/cm2) occurred in the 32- to 36-yr age group. In men, peak lumbar BMD (1.181+/-0.153 g/cm2) and femoral BMD (1.096+/-0.159 g/cm2) both occurred in the 20- to 24-yr age group. When standardized to mg/cm2 units using established formulas, Iranian peak bone mass values are comparable with that of Western countries and are generally higher than that of Eastern Asian and Middle Eastern countries. 相似文献
5.
Palytoxin, a highly toxic natural product isolated from zoanthids of the genus Palythoa, is accumulated by a wide range of fishes and marine invertebrates used as food in the Indo-Pacific. It is responsible for many incidents of human morbidity and mortality. The toxin is a potent smooth muscle spasmogen. The cause of the contraction of smooth muscle is unclear, but recent work strongly suggests that it is primarily initiated by the release of neurotransmitters from the motor innervation of the smooth muscle. We show here that palytoxin caused the swelling of the muscle cells and some internal organelles of the anococcygeus muscle of the rat, but no substantial structural damage to the tissue. Axons and Schwann cells were also swollen but the most dramatic feature was the depletion of synaptic vesicles from putative release sites in the axons. Some axons were physically damaged following exposure to the toxin, but this was relatively uncommon (<10% of all axons studied). In the majority of axons there was no damage to nerve terminal membranes, but there was damage to mitochondria. The depletion of vesicles involved all types – clear, dense-cored, large and small. Our observations and pharmacological data gathered elsewhere, provide a neuropathological basis for the spasmogenic activity of palytoxin. 相似文献
6.
7.
aVR sign as a risk factor for life-threatening arrhythmic events in patients with Brugada syndrome 总被引:2,自引:0,他引:2
BACKGROUND: Risk stratification in Brugada syndrome (BS) is controversial, especially in asymptomatic individuals. OBJECTIVE: The aim of this study was to evaluate the significance of lead aVR in patients with BS. METHODS: Twenty-four patients with the electrocardiogram pattern of BS (24 male, mean age 32.1 +/- 13.6 years) and 24 healthy age- and gender-matched controls were studied. RESULTS: Thirteen patients were symptomatic. The R-wave amplitude or R/q ratio in lead aVR was significantly greater in patients experiencing a recurrence compared with those who did not. The aVR sign was defined as R wave >/= 0.3 mV or R/q >/= 0.75 in lead aVR. Most of the recurrences (78%) were in patients with present aVR sign; 84% of BS patients with present aVR sign had events during follow-up. In contrast, only 27% of BS patients with absent aVR sign had events during follow-up. CONCLUSION: Our study shows significant correlation between a prominent R wave in lead aVR (aVR sign) and risk for development of arrhythmic events in BS. In the presence of BS, prominent R wave in lead aVR may reflect more right ventricular conduction delay and subsequently more electrical heterogeneity, which in turn is responsible for a higher risk of arrhythmia. 相似文献
8.
Mozammil Hussain Raghu N. Natarajan Amir H. Fayyazi Brian R. Braaksma Gunnar B.J. Andersson Howard S. An 《The spine journal》2009,9(12):1016-1023
Background contextAnterior corpectomy and reconstruction with bone graft and a rigid screw-plate construct is an established procedure for treatment of cervical neural compression. Despite its reliability in relieving symptoms, there is a high rate of construct failure, especially in multilevel cases.PurposeThere has been no study evaluating the biomechanical effects of screw angulation on construct stability; this study investigates the C4–C7 construct stability and load-sharing properties among varying screw angulations in a rigid plate-screw construct.Study designA finite element model of a two-level cervical corpectomy with static anterior cervical plate.MethodsA three-dimensional finite element (FE) model of an intact C3–T1 segment was developed and validated. From this intact model, a fusion model (two-level [C5, C6] anterior corpectomy) was developed and validated. After corpectomy, allograft interbody fusion with a rigid anterior screw-plate construct was created from C4 to C7. Five additional FE models were developed from the fusion model corresponding to five different combinations of screw angulations within the vertebral bodies (C4, C7): (0°, 0°), (5°, 5°), (10°, 10°), (15°, 15°), and (15°, 0°). The fifth fusion model was termed as a hybrid fusion model.ResultsThe stability of a two-level corpectomy reconstruction is not dependent on the position of the screws. Despite the locked screw-plate interface, some degree of load sharing is transmitted to the graft. The load seen by the graft and the shear stress at the bone-screw junction is dependent on the angle of the screws with respect to the end plate. Higher stresses are seen at more divergent angles, particularly at the lower level of the construct.ConclusionThis study suggests that screw divergence from the end plates not only increases load transmission to the graft but also predisposes the screws to higher shear forces after corpectomy reconstruction. In particular, the inferior screw demonstrated larger stress than the upper-level screws. In the proposed hybrid fusion model, lower stresses on the bone graft, end plates, and bone-screw interface were recorded, inferring lower construct failure (end-plate fractures and screw pullout) potential at the inferior construct end. 相似文献
9.
10.
Amir A Jamali Christopher Deuel Aimee Perreira Christopher J Salgado John C Hunter E Bradley Strong 《Computer aided surgery》2007,12(5):278-285
INTRODUCTION: Traditional advanced imaging modalities such as CT and MRI are limited in their ability to perform accurate linear distance and angular measurements regardless of anatomical orientation. The construction of 3D models has been used to perform anthropometric analyses as well as in the reconstruction of rapid prototypes. We hypothesized that such measurements would be precise to within 2 mm or 2 degrees of measurements performed with a coordinate measurement machine (CMM). We also hypothesized that there would be a high degree of interobserver reliability with these measurements. MATERIALS AND METHODS: Multiple aluminum screws were implanted in various positions in three foam pelvises which were subsequently scanned by CT and rendered as 3D models using a commercially available software package (Mimics). Linear and angular measurements were performed using a CMM machine, the software package, and a dial caliper or goniometer. The deviation of the measurements from the CMM data was compared using ANOVA. The interobserver reliability of both the manual and computer-generated measurements was calculated. RESULTS: The mean difference between the CMM distances and those measured manually and with the software was 2.12 +/- 1.20 mm and 1.57 +/- 1.05 mm, respectively. The mean difference between the CMM angular measurements and the angular measurements performed manually and with the software was 4.07 +/- 4.70 degrees and 1.62 +/- 1.32 degrees, respectively. In all cases, the manual measurements were significantly less accurate (p < 0.0001) and there was a high degree of interobserver reliability. CONCLUSIONS: Computer-generated measurements taken from three-dimensionally reconstructed models are more accurate than manual measurements and are within 2 mm and 2 degrees of measurements performed with a CMM. These measurements have high interobserver reliability. 相似文献