全文获取类型
收费全文 | 8406篇 |
免费 | 447篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 143篇 |
儿科学 | 437篇 |
妇产科学 | 221篇 |
基础医学 | 855篇 |
口腔科学 | 222篇 |
临床医学 | 688篇 |
内科学 | 1861篇 |
皮肤病学 | 159篇 |
神经病学 | 581篇 |
特种医学 | 301篇 |
外科学 | 1695篇 |
综合类 | 179篇 |
一般理论 | 2篇 |
预防医学 | 367篇 |
眼科学 | 192篇 |
药学 | 494篇 |
中国医学 | 32篇 |
肿瘤学 | 462篇 |
出版年
2023年 | 65篇 |
2022年 | 205篇 |
2021年 | 329篇 |
2020年 | 196篇 |
2019年 | 226篇 |
2018年 | 275篇 |
2017年 | 186篇 |
2016年 | 237篇 |
2015年 | 260篇 |
2014年 | 387篇 |
2013年 | 504篇 |
2012年 | 653篇 |
2011年 | 652篇 |
2010年 | 378篇 |
2009年 | 299篇 |
2008年 | 493篇 |
2007年 | 553篇 |
2006年 | 527篇 |
2005年 | 480篇 |
2004年 | 421篇 |
2003年 | 361篇 |
2002年 | 307篇 |
2001年 | 112篇 |
2000年 | 93篇 |
1999年 | 74篇 |
1998年 | 39篇 |
1997年 | 22篇 |
1996年 | 31篇 |
1995年 | 38篇 |
1994年 | 30篇 |
1993年 | 29篇 |
1992年 | 44篇 |
1991年 | 50篇 |
1990年 | 28篇 |
1989年 | 43篇 |
1988年 | 29篇 |
1987年 | 21篇 |
1986年 | 24篇 |
1985年 | 20篇 |
1984年 | 18篇 |
1983年 | 15篇 |
1982年 | 8篇 |
1981年 | 21篇 |
1980年 | 14篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1973年 | 7篇 |
1972年 | 6篇 |
1967年 | 12篇 |
排序方式: 共有8891条查询结果,搜索用时 15 毫秒
61.
International Urology and Nephrology - To evaluate the effect of masturbation on the spontaneous expulsion of distal ureteral stones 5–10 mm in size. A total of 128 men with distal... 相似文献
62.
Hamed Nikoupour MD Peyman Arasteh MD MPH Alireza Shamsaeefar MD Fardin Ghanbari MD Arash Boorboor MD Ali Mosa Jafar Almayali MD Mojtaba Shafiekhani PharmD Ph.D Pirouz Samidoust MD Reza Shahriarirad MD Alireza Shojazadeh MD Keivan Ranjbar MD Mohammad Hasan Darabi MD Sina Tangestanipour MD Seyed Morteza Hosseini MD Leila Zahiri MD Saman Nikeghbalian MD 《JPEN. Journal of parenteral and enteral nutrition》2022,46(4):946-957
63.
Natural Convection Heat Transfer in a Porous Cavity with Sinusoidal Temperature Distribution Using Cu/Water Nanofluid: Double MRT Lattice Boltzmann Method
下载免费PDF全文
![点击此处可从《Communications In Computational Physics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hasan Sajjadi Amin Amiri Delouei Rasul Mohebbi Mohsen Izadi & Sauro Succi 《Communications In Computational Physics》2021,29(1):292-318
In this study, natural convection flow in a porous cavity with sinusoidal
temperature distribution has been analyzed by a new double multi relaxation time
(MRT) Lattice Boltzmann method (LBM). We consider a copper/water nanofluid filling a porous cavity. For simulating the temperature and flow fields, D2Q5 and D2Q9
lattices are utilized respectively, and the effects of different Darcy numbers (Da) (0.001-0.1) and various Rayleigh numbers (Ra) ($10^3$-$10^5$) for porosity ($ε$) between 0.4 and 0.9
have been considered. Phase deviation ($θ$) changed from 0 to $π$ and the volume fraction
of nanoparticles (Ø) varied from 0 to 6%. The present results show a good agreement
with the previous works, thus confirming the reliability the new numerical method
proposed in this paper. It is indicated that the heat transfer rate increases at increasing
Darcy number, porosity, Rayleigh number, the volume fraction of nanoparticles and
phase deviation. However, the most sensitive parameter is the Rayleigh number. The
maximum Nusselt deviation is 10%, 32% and 33% for Ra=$10^3$, $10^4$ and $10^5$, respectively, with $ε = 0.4$ to $ε = 0.9$. It can be concluded that the effect of Darcy number on
the heat transfer rate increases at increasing Rayleigh number, yielding a maximum
enhancement of the average Nusselt number around 12% and 61% for Ra=$10^3$ and
Ra=$10^5$, respectively. 相似文献
64.
Giving adequate information about febrile convulsion and its prognosis would be helpful in alleviating parental stress, and
would contribute to decrease in the morbidity of febrile convulsion. In this study, the knowledge level of parents on taking
body temperature, and decreasing high fever, their attitudes during febrile convulsion and the impact of febrile convulsion
on parents are evaluated. One hundred seventy-four parents of 132 children with FC were enrolled in the study. Twenty-seven
per cent of parents had no thermometer at home, 32.8% of them did not know how to take a temperature, 72.2% of them did not
know the minimum range of increased body temperature, and 69.5% of them did not know how to decrease the increased body temperature.
Thirty-six percent of parents recognised the convulsions when their children suffered from them, the others assumed the convulsion
were fainting spells (6.9%), near death state (38.5%) and suffocation (18.4%). Thirty-six per cent of parents brought their
children to the hospital without doing anything themselves. Most parents (91.4%) had a fear of a recurrence of febrile convulsion
in their children. Seventy-four per cent of parents complained of insomia, 24.3% parents had dyspeptic symptoms even 14 parents
had weight loss due to dyspepsia. 相似文献
65.
The characteristics of facial nerve electromyography at various levels of neuromuscular blockade are unclear. Partial blockade is well known to facilitate anesthetic safety and management. However, the use of neuromuscular blockage in many skull base procedures is avoided to allow intraoperative facial nerve monitoring.We studied the influence of various levels of neuromuscular blockade on facial nerve stimulation in the New Zealand white rabbit. The facial nerve was exposed in the middle ear of six rabbits. Using electromyographic-type facial nerve monitor, we recorded the facial electromyography signals in these rabbits at increasing levels of vecuronium-induced neuromuscular blockade. All animals demonstrated reliable facial electromyography response at all levels of partial neuromuscular blockade (P < .02). Five of the six animals could be monitored throughout complete blockade. These results clearly demonstrate that rabbit facial electromyography monitoring is possible under neuromuscular blockade. The effect of neuromuscular blockers on facial electromyography monitoring deserves further study, as partial blockade would greatly facilitate the management of anesthesia in otologic, neurotologic, and skull base surgery. 相似文献
66.
Biaggi RR Vollman MW Nies MA Brener CE Flakoll PJ Levenhagen DK Sun M Karabulut Z Chen KY 《The American journal of clinical nutrition》1999,69(5):898-903
BACKGROUND: Over the past decade, considerable attention has been paid to accurately measuring body composition in diverse populations. Recently, the use of air-displacement plethysmography (AP) was proposed as an accurate, comfortable, and accessible method of body-composition analysis. OBJECTIVE: The purpose of this study was to compare measurements of percentage body fat (%BF) by AP and 2 other established techniques, hydrostatic weighing (HW) and bioelectrical impedance analysis (BIA), in adults. DESIGN: The sample consisted of healthy men (n = 23) and women (n = 24). %BF was measured by AP, HW, and BIA. RESULTS: In the total group, %BF(AP) (25.0+/-8.9%) was not significantly different from %BF(HW) (25.1+/-7.7%) or %BF(BIA) (23.9+/-7.7%), and %BF(AP) was significantly correlated with %BF(HW) (r = 0.944, P < 0.001) and with %BF(BIA) (r = 0.859, P < 0.01). Compared with HW, AP underestimated %BF in men (by -1.24+/-3.12%) but overestimated %BF in women (by 1.02+/-2.48%), indicating a significant sex effect (P < 0.05). The differences in estimation between AP and BIA and between BIA and HW were not significantly different between the sexes. CONCLUSION: AP is an accurate method for assessing body composition in healthy adults. Future studies should assess further the cause of the individual variations with this new method. 相似文献
67.
68.
69.
Mengü Burhanoğlu Sarenur Tütüncüoğlu Canan çoker Hasan Tekgül Tugrul Özgür 《European journal of pediatrics》1996,155(6):498-501
To understand further the role of trace elements in the pathogenesis of febrile convulsions, serum zinc (Zn), copper (Cu), magnesium (Mg) and CSF Zn, Cu, Mg and protein levels were measured by spectrometry in patients with febrile convulsion (n=19), bacterial meningitis (n=9), viral CNS infection (n=16) and in the control groupn=10) which consisted of children with signs of meningeal irritation due to upper respiratory tract infection but normal CSF findings. Samples were obtained within 6 h after admission to hospital. Mean serum and CSF Zn levels in the febrile convulsion group were significantly lower than in the other groups (for serum Zn: 0.66±0.03 mg/l vs 0.98±0.07 mg/l, 1.06±0.08 mg/l, 1.05±0.09 mg/lP<0.05; for CSF Zn: 22.96±1.62 g/l vs 75.47 ±6.9 g/l, 50.32±5.235 g/l, 39.85 ±2.81 g/lP<0.05). A linear relationship was established between serum Zn and CSF Zn levels (P<0.001). Mean CSF Zn, Cu and protein levels in the bacterial meningitis group were significantly higher than in the other groups (for CSF Cu 63.94±6.33 g/l vs 38.77±2.70 g/l, 35.84±3.48 g/l, 33.86±2.88 g/lP<0.05; for CSF protein 0.80 ± 0.12 g/l vs 0.22±0.02 g/l, 0.53±0.08 g/l, 0.19±0.01 g/lP<0.05). In children with meningitis, the elevation of the mean CSF Zn and Cu levels may result from the breakdown of the blood-brain barrier and subsequent leakage of trace elements and protein from serum to CSF. There was no significant difference between the four groups in terms of mean serum Mg and mean CSF Mg levels.Conclusion Serum and CSF Zn levels are decreased in children with febrile seizures. Zinc deprivation may play a role in the pathogenesis of febrile seizures. 相似文献
70.
Commonly used organophosphate pesticide dichlorvos is known to cause neurologic lesions. However, the exact mechanism of its neurotoxicity is, as yet, unclear. Using dose-dependent inhibition of acetylcholinesterase activity as an index of its neurotoxicity, effects of three different doses of dichlorvos (0.6 mg, 1.5 mg, and 3.0 mg/kg body weight i.p. daily for 10 days) have been observed on the rate of lipid-peroxidation in the cerebrum, cerebellum and brain stem of albino rats. Simultaneously, electron microscopic study of the dichlorvos intoxicated rat cerebellum was also carried out. Dose-dependent increase in the rate of lipid peroxidation was found in all the brain regions, and increased incidence of lipofuscin-like pigment granules was discernible in the Purkinie cells of the cerebellar cortex. 相似文献