全文获取类型
收费全文 | 4754篇 |
免费 | 349篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 122篇 |
儿科学 | 122篇 |
妇产科学 | 115篇 |
基础医学 | 717篇 |
口腔科学 | 152篇 |
临床医学 | 436篇 |
内科学 | 932篇 |
皮肤病学 | 50篇 |
神经病学 | 267篇 |
特种医学 | 130篇 |
外国民族医学 | 3篇 |
外科学 | 790篇 |
综合类 | 97篇 |
一般理论 | 4篇 |
预防医学 | 294篇 |
眼科学 | 120篇 |
药学 | 408篇 |
中国医学 | 51篇 |
肿瘤学 | 322篇 |
出版年
2024年 | 5篇 |
2023年 | 53篇 |
2022年 | 132篇 |
2021年 | 215篇 |
2020年 | 132篇 |
2019年 | 177篇 |
2018年 | 233篇 |
2017年 | 142篇 |
2016年 | 158篇 |
2015年 | 177篇 |
2014年 | 240篇 |
2013年 | 279篇 |
2012年 | 494篇 |
2011年 | 434篇 |
2010年 | 222篇 |
2009年 | 173篇 |
2008年 | 247篇 |
2007年 | 257篇 |
2006年 | 230篇 |
2005年 | 197篇 |
2004年 | 161篇 |
2003年 | 161篇 |
2002年 | 137篇 |
2001年 | 48篇 |
2000年 | 48篇 |
1999年 | 38篇 |
1998年 | 36篇 |
1997年 | 22篇 |
1996年 | 20篇 |
1995年 | 10篇 |
1994年 | 18篇 |
1993年 | 15篇 |
1992年 | 22篇 |
1991年 | 22篇 |
1990年 | 14篇 |
1989年 | 15篇 |
1988年 | 20篇 |
1987年 | 21篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1974年 | 8篇 |
1973年 | 10篇 |
1972年 | 3篇 |
1971年 | 4篇 |
排序方式: 共有5132条查询结果,搜索用时 15 毫秒
31.
Hamid M Fallet-Bianco C Delmas V Plaisant O 《Surgical and radiologic anatomy : SRA》2002,24(3-4):194-200
To increase our understanding of the clinical anatomy of the epidural space, the human lumbar anterior epidural space was studied morphologically and developmentally. Histological transverse sections of human lumbar spines were taken at the level of the intervertebral disc and the vertebral body in adult specimens and in fetuses aged 13, 15, 21, 32 and 39 weeks (menstrual age). At 13 weeks, connective tissue filled the epidural space. The dura mater was attached anteriorly to the posterior longitudinal ligament (PLL). The PLL was attached to the vertebral body beside the midline, whereas it adhered to the posterior edge of intervertebral disc. The anterior internal vertebral venous plexus was located anterolaterally and anteromedially. The vertebral canal was lined with connective tissue that differentiated in a periosteum in contact with the ossification centers. At 15 weeks, the PLL was composed of deep and superficial layers. At 21 weeks, the attachment between the dura mater and PLL was ligament-like at the level of the vertebral body. At 32 weeks, the dura mater was adherent to the superficial layer of PLL. At 39 weeks, groups of adipocytes were identified, and the dura mater was attached to the PLL by some ligaments. There were many more similarities between the adult and the 39-week fetus. In conclusion, some differences in the anatomy of the epidural space exist at each fetal stage studied. The structures of the epidural space are already formed in the fetus of 13 weeks, but they differentiate progressively within the connective tissue. 相似文献
32.
Ghavamzadeh R Haddadi-Asl V Mirzadeh H 《Journal of biomaterials science. Polymer edition》2004,15(8):1019-1031
This study describes the potentiality of crosslinked hydrogels comprised of gelatin and polyacrylic acid (CHGP) as a biological glue for soft tissues and compares its bonding strength with that of fibrin glue. Water-soluble carbodimide (WSC) was used to crosslink the mixture of gelatin and polyacrylic acid (PAA). An addition of PAA to gelatin increases bonding strength and reduces the gelation time and WSC concentration. Increasing the gelatin, WSC and PAA concentration increases the bonding strength. There is a critical concentration to have a maximum bonding strength. The cured hydrogel exhibited sufficient adhesion to mouse skin with a higher bonding strength than fibrin glue. The in vitro test has been done for evaluating CHGP toxicity. 相似文献
33.
Daily running promotes spatial learning and memory in rats. 总被引:1,自引:0,他引:1
Hojjatallah Alaei Rohallah Moloudi Ali Reza Sarkaki Hamid Azizi-Malekabadi Osmo Hanninen 《Pathophysiology》2007,14(2):105-108
Previous studies on exercise have shown that physical activity improves learning and memory. Present study was performed to determine the effects of acute, chronic and continuous exercise with different periods on spatial learning and memory recorded as the latency and length of swim path in the Morris water maze testing in subsequent 8 days. Four rat groups were included as follows: (1) group C, controls which did not exercise; (2) group A, 30 days treadmill running before and 8 days during the Morris water maze testing period; (3) group B, 30 days exercise before the Morris water maze testing period only; (4) group D, 8 days exercise only during the Morris water maze testing period. The results showed that chronic (30 days) and continuous (during 8 days of Morris water maze testing days) treadmill training produced a significant enhancement in spatial learning and memory which was indicated by decreases in path length and latency to reach the platform in the Morris water maze test (p<0.05). The benefits in these tests were lost in 3 days, if the daily running session was abandoned. In group D with acute treadmill running (8 days exercise only) the difference between the group A disappeared in 1 week and benefit seemed to be obtained in comparison with the controls without running program. In conclusion the chronic and daily running exercises promoted learning and memory in Morris water maze, but the benefits were lost in few days without daily running sessions in adult rats. 相似文献
34.
Ahmed Hassan Albelbeisi Ali Albelbeisi Abdel Hamid El Bilbeisi Mahmoud Taleb Amirhossein Takian Ali Akbari-Sari 《Ethiopian journal of health sciences》2021,31(1):73
BackgroundDespite the huge numbers of the universally produced and employed protocols, the adherence with them is still low to moderate in the healthcare settings. This study was employed to assess the attitudes of Palestinian healthcare professionals in Gaza Strip to health education and counseling on healthy behaviours protocol (WHO-PEN Protocol 2), for patients with non-communicable diseases in the Ministry of Health primary healthcare centers.MethodsThis cross-sectional study was conducted with a census sample of all governmental family physicians and nurses (n=175). The study questionnaire was developed based on Cabana theoretical framework. The Arabic version questionnaire was developed based on the cross-cultural adaptation framework. The psychometric properties of the Arabic version questionnaire was finally evaluated.ResultsThe psychometric properties of the Arabic version questionnaire showed good construct validity and internal consistency reliability. The overall adherence level to WHO-PEN Protocol 2 was 70.0, SD=6.9. The main perceived barriers were lack of incentive, patients'' factors, and lack of time. In general, most of healthcare professional respondents had a positive attitude toward the protocol, but this attitude was not predictor to protocol adherence.ConclusionThe good validity and reliability of the questionnaire can provide support for the accuracy of the study results. Varied implementation strategies targeting the major barriers derived from the study are extremely required for addressing the lack of incentives, patients'' factors and time constraints. 相似文献
35.
Hamid Reza Marzban 《Optimal control applications & methods.》2021,42(1):2-29
This research provides a new framework based on a hybrid of block‐pulse functions and Legendre polynomials for the numerical examination of a special class of scalar nonlinear fractional optimal control problems involving delay. The concepts of the fractional derivative and the fractional integral are employed in the Caputo sense and the Riemann‐Liouville sense, respectively. In accordance with the notion of the Riemann‐Liouville integral, we derive a new integral operator related to the proposed basis called the operational matrix of fractional integration. By employing two significant operators, namely, the delay operator and the integral operator connected to the hybrid basis, the system dynamics of the primal optimal control problem converts to another system involving algebraic equations. Consequently, the optimal control problem under study is reduced to a static optimization one that is solved by existing well‐established optimization procedures. Some new theoretical results regarding the new basis are obtained. Various kinds of fractional optimal control problems containing delay are examined to measure the accuracy of the new method. The simulation results justify the merits and superiority of the devised procedure over the existing optimization methods in the literature. 相似文献
36.
Mina Saeedneja Mohammadreza Zafarghandi Narjes Khalili Vali Baigi Moein Khormali Zahra Ghodsi Mahdi Sharif-Alhoseini Gerard M. O’Reilly Khatereh Naghdi Melika Khaleghi-Nekou Seyed mohammad Piri Vafa Rahimi-Movaghar Somayeh Bahrami Marjan Laal Mahdi Mohammadzadeh Esmaeil Fakharian Habibollah Pirneja Hamid Pahlavanhosseini Payman Salamati Homayoun Sadeghi-Bazargani 《中华创伤杂志(英文版)》2021,24(3):153-158
Purpose: Injuries are one of the leading causes of death and lead to a high social and financial burden. Injury patterns can vary significantly among different age groups and body regions. This study aimed to evaluate the relationship between mechanism of injury, patient comorbidities and severity of injuries.
Methods: The study included trauma patients from July 2016 to June 2018, who were admitted to Sina Hospital, Tehran, Iran. The inclusion criteria were all injured patients who had at least one of the following: hospital length of stay more than 24 h, death in hospital, and transfer from the intensive care unit of another hospital. Data collection was performed using the National Trauma Registry of Iran minimum dataset.
Results: The most common injury mechanism was road traffic injuries (49.0%), followed by falls (25.5%). The mean age of those who fell was significantly higher in comparison with other mechanisms (p < 0.001). Severe extremity injuries occurred more often in the fall group than in the vehicle collision group (69.0% vs. 43.5%, p < 0.001). Moreover, cases of severe multiple trauma were higher amongst vehicle collisions than injuries caused by falls (27.8% vs. 12.9%, p = 0.003).
Conclusion: Comparing falls with motor vehicle collisions, patients who fell were older and sustained more extremity injuries. Patients injured by motor vehicle collision were more likely to have sustained multiple trauma than those presenting with falls. Recognition of the relationship between mechanisms and consequences of injuries may lead to more effective interventions. 相似文献
37.
38.
39.
Arun Sahai Ased Ali Rachel Barratt Mohammed Belal Suzanne Biers Rizwan Hamid Christopher Harding Richard Parkinson Sheilagh Reid Nikesh Thiruchelvam Section of Female Neurological Urodynamic Urology British Association of Urological Surgeons 《BJU international》2021,128(5):539-547
Injuries to the bladder and ureter are uncommon but usually require prompt urological management. Due to their infrequent nature, Urologists maybe unfamiliar with managing these acute problems and may not work in specialist centres with readily available expertise in open and abdominal surgery. We aim to provide advice in the form of a consensus statement led by the Female, Neurological and Urodynamic Urology (FNUU) Section of the British Association of Urological Surgeons (BAUS), in consultation with BAUS members and consultants working in units throughout the UK, to create a comprehensive management pathway and a series of statements to aid clinicians. 相似文献
40.
Dlugosz LJ Hocter WJ Kaiser KS Knoke JD Heller JM Hamid NA Reed RJ Kendler KS Gray GC 《Journal of clinical epidemiology》1999,52(12):90-1278
Effects of Persian Gulf War (August 2, 1990–July 31, 1991) and Gulf War occupation on post-War hospitalization risk were evaluated through Cox proportional hazards modeling. Active-duty men (n = 1,775,236) and women (n = 209,760) in the Army, Air Force, Navy, and Marine Corps had 30,539 initial postwar hospitalizations for mental disorders between June 1, 1991 and September 30, 1993. Principal diagnoses in the Defense Manpower Data Center hospitalization database were grouped into 10 categories of ICD-9-CM codes. Gulf War service was associated with significantly greater risk for acute reactions to stress and lower risk for personality disorders and adjustment reactions among men. Personnel who served in ground war support occupations (men and women) were at greater risk for postwar drug-related disorders. Men who served in ground war combat occupations were at higher risk for alcohol-related disorders. Longitudinal studies of health, hospitalization, and exposure beginning at recruitment, are needed to better understand how exposure to combat affects the mental health of military personnel. 相似文献