全文获取类型
收费全文 | 35623篇 |
免费 | 3064篇 |
国内免费 | 1836篇 |
专业分类
耳鼻咽喉 | 578篇 |
儿科学 | 508篇 |
妇产科学 | 819篇 |
基础医学 | 4177篇 |
口腔科学 | 564篇 |
临床医学 | 4187篇 |
内科学 | 6235篇 |
皮肤病学 | 813篇 |
神经病学 | 1919篇 |
特种医学 | 1197篇 |
外国民族医学 | 17篇 |
外科学 | 3612篇 |
综合类 | 4278篇 |
现状与发展 | 4篇 |
一般理论 | 7篇 |
预防医学 | 2333篇 |
眼科学 | 798篇 |
药学 | 3638篇 |
23篇 | |
中国医学 | 1651篇 |
肿瘤学 | 3165篇 |
出版年
2024年 | 83篇 |
2023年 | 485篇 |
2022年 | 1150篇 |
2021年 | 1528篇 |
2020年 | 1112篇 |
2019年 | 1163篇 |
2018年 | 1284篇 |
2017年 | 1093篇 |
2016年 | 1046篇 |
2015年 | 1549篇 |
2014年 | 1899篇 |
2013年 | 1892篇 |
2012年 | 2665篇 |
2011年 | 2805篇 |
2010年 | 1794篇 |
2009年 | 1332篇 |
2008年 | 1929篇 |
2007年 | 1837篇 |
2006年 | 1861篇 |
2005年 | 1823篇 |
2004年 | 1330篇 |
2003年 | 1270篇 |
2002年 | 1092篇 |
2001年 | 899篇 |
2000年 | 823篇 |
1999年 | 750篇 |
1998年 | 458篇 |
1997年 | 413篇 |
1996年 | 334篇 |
1995年 | 306篇 |
1994年 | 275篇 |
1993年 | 197篇 |
1992年 | 327篇 |
1991年 | 284篇 |
1990年 | 218篇 |
1989年 | 171篇 |
1988年 | 192篇 |
1987年 | 158篇 |
1986年 | 123篇 |
1985年 | 117篇 |
1984年 | 84篇 |
1983年 | 44篇 |
1982年 | 25篇 |
1981年 | 35篇 |
1980年 | 21篇 |
1979年 | 32篇 |
1978年 | 24篇 |
1977年 | 19篇 |
1975年 | 18篇 |
1973年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
将2例HBV_2患者血清HBsAg纯化,分析了HBV_2的HBsAg氨基酸组成,并与分子量为630198道尔顿HBV_1的HBsAg三种多肽氨基醚组成比较。实验发现,HBV_2与HBV_1的HBsAg的氨基醚组成有较大区别,且区别指数均在13以上。提示HBV_1和HBV_2的HBsAg在一级结构上存在较大差异;HBV_2可能系一新的乙型肝炎病毒,也可能系由于HBV_1S区核苷酸突变所致的变异株。 相似文献
52.
Effects of sodium salts of various monovalent inorganic anions on transdermal permeation of salicylic acid were investigated. In in-vitro experiment using a Franz-type diffusion cell and excised mouse skin, the permeation-enhancing activities of the sodium salts of inorganic anions were roughly proportional to lyotropic Hofmeister swelling abilities of the anions; F?<SO4 2?<Cl? <ClO4 ?<NO3 <SCN? <Br <I?, i.e. l, Br and SCN increased the flux of drugs through the mouse skin, while F?, SO4 2?, Cl?, ClO4 ? and NO3 ? decreased or did not affect the flux. In invivo experiment using the rabbit as the test animal, the plasma concentration of salicylic acid of the rabbit to which 10%-salicylic acid ointment containing 5%-Nal or NaBr was applied was significantly higher than that of the rabbit to which the ointment without the electrolytes was applied. The amounts of sterol leached out of stratum corneum sheet when the sheet was immersed in aqueous solutions of Nal, NaBr, or NaSCN were much more than that of stratum corneum immersed in aqueous solutions of the other inorganic anions. The FTIR/ATR spectroscopy showed that the peaks at 2853 cm?1 and 2924 cm?1 in the IR absorption spectrum of the stratum corneum sheet of the mouse were shifted to higher frequencies by the anions which enhanced the transdermal drug permeation, while not shifted by the anions which did not have any permeation-enhancing activities or have permeation-reducing activities. These results suggest that sodium salts of some anions such as iodide, bromide and thiocyanate enhance transdermal permeation of salicylic acid through swelling and perturbation of the skin structure by these anions. 相似文献
53.
Ketanserin降低清醒自发性高血压大鼠血压波动性的机理初探 总被引:2,自引:0,他引:2
应用计算机化清醒大鼠血流动力学测定技术,观察5-HT2受体阻滞剂Ritanserin(Rit)和α1受体阻滞剂哌唑嗪对清醒自发性高血压大鼠(SHR)的血压、血压波动性(BPV)和动脉压力感受性反射血压控制部分(ABR-BP)的效应,旨在初步探讨兼具5-HT2受体和α1受体阻滞作用地新型抗高血压药Ketanserin降低BPV的机制。结果表明:Rit对SHR无降压作用,但侧脑室给药明显提高ABR-B 相似文献
54.
55.
研究目的调查分析出院后精神分裂症患者的心理状况,了解存在的问题并探讨解决的对策。研究方法对77例出院后精神分裂症病人就22项心理问题进行调查统计,并对比男女患者差异。结果男性易发脾气、借酒消愁、因病影响工作安排的现象较女性突出,而女性的婚姻状况较紧性明显。结论社区防治的病人心理问题较繁杂,因此防治工作应重视患者的心理特点,解决患者的实际问题。 相似文献
56.
Background Previous studies have noted that there is a high utilization rate of traditional Chinese medicine (TCM) services in Taiwan, China and in western countries, but few studies investigated factors associated with the utilization of TCM in Taiwan. This study analyzes the utilization rate and the factors associated with the utilization of TGM in Taiwan. Methods Data for this study were from the 2002 HPKAP Survey that conducted the face-to-face questionnaire interviews of people aged 15 years and over from October 2002 to March 2003 in Taiwan. This study analyzed the utilization of TCM outpatient services, including admission to the hospital and clinic visits. Results A total of 26 755 participants completed the survey in the six-month period. The data revealed that 10.4% of participants had utilized TCM services in the past one month while 4.2% of participants utilized TCM only (without using Western medicine outpatient services (WM) or Folk therapy (F'I')). The average visits of TCM services per patient was higher among people who had utilized TCM and FT services (2.68 visits) than among those who had utilized WM and FT services (2.15 visits) or TCM services alone (2.15 visits) during the previous one month. Younger people (odds ratio OR= 1.78, 95%C/= 1.47-2.16), women (compared with men), and people with higher education levels (OR = 1.58, 95%CI =1.25-1.98) were more likely to visit TCM than compared groups. People with self-reported poor health status (OR = 2.07,95%CI = 1.76-2.44) and people who exercise regularly (OR = 1.17, 95%CI = 1.07-1.27) had higher ORs to visit TCM service than comparison group.Conclusions There is a high utilization of TCM in Taiwan. Further studies are needed to investigate the related factors and determinants between the utilization of TCM and the utilization of FT in Taiwan. 相似文献
57.
Performance measurement of the microPET focus 120 scanner. 总被引:6,自引:0,他引:6
Jin Su Kim Jae Sung Lee Ki Chun Im Su Jin Kim Seog-Young Kim Dong Soo Lee Dae Hyuk Moon 《Journal of nuclear medicine》2007,48(9):1527-1535
The microPET Focus 120 scanner is a third-generation animal PET scanner dedicated to rodent imaging. Here, we report the results of scanner performance testing. METHODS: A (68)Ge point source was used to measure energy resolution, which was determined for each crystal and averaged. Spatial resolution was measured using a (22)Na point source with a nominal size of 0.25 mm at the system center and various off-center positions. Absolute sensitivity without attenuation was determined by extrapolating the data measured using an (18)F line source and multiple layers of absorbers. Scatter fraction and counting rate performance were measured using 2 different cylindric phantoms simulating rat and mouse bodies. Sensitivity, scatter fraction, and noise equivalent counting rate (NECR) experiments were repeated under 4 different conditions (energy window, 250 approximately 750 keV or 350 approximately 650 keV; coincidence window, 6 or 10 ns). A performance phantom with hot-rod inserts of various sizes was scanned, and several animal studies were also performed. RESULTS: Energy resolution at a 511-keV photopeak was 18.3% on average. Radial, tangential, and axial resolution of images reconstructed with the Fourier rebinning (FORE) and filtered backprojection (FBP) algorithms were 1.18 (radial), 1.13 (tangential), and 1.45 mm full width at half maximum (FWHM) (axial) at center and 2.35 (radial), 1.66 (tangential), and 2.00 mm FWHM (axial) at a radial offset of 2 cm. Absolute sensitivities at transaxial and axial centers were 7.0% (250 approximately 750 keV, 10 ns), 6.7% (250 approximately 750 keV, 6 ns), 4.0% (350 approximately 650 keV, 10 ns), and 3.8% (350 approximately 650 keV, 6 ns). Scatter fractions were 15.9% (mouse phantom) and 35.0% (rat phantom) for 250 approximately 750 keV and 6 ns. Peak NECR was 869 kcps at 3,242 kBq/mL (mouse phantom) and 228 kcps at 290 kBq/mL (rat phantom) at 250 approximately 750 keV and 6 ns. Hot-rod inserts of 1.6-mm diameter were clearly identified, and animal studies illustrated the feasibility of this system for studies of whole rodents and mid-sized animal brains. CONCLUSION: The results of this independent field test showed the improved physical characteristics of the F120 scanner over the previous microPET series systems. This system will be useful for imaging studies on small rodents and brains of larger animals. 相似文献
58.
中风后癫痫的临床研究 总被引:5,自引:0,他引:5
本文报告36例中风后癫痫发作的临床和CT资料。通过回顾性病历复习和随访发现,中风后癫痫的发生率占同期住院中风患者的5.26%,以蛛网膜下腔出血和脑栓塞发生癫痫比率最高,分别为15%和12.5%。癫痫发作与CT所见病灶分布密切相关,皮质病灶较皮质下病灶更易发生病病。癫痫发作可发生于中风后任何时期,但早期癫痫以出血性中风多见,而迟发性癫痫则更多见于脑梗塞患者。 相似文献
59.
60.
采用高效液相色谱法测定了异丙酚在不同温度下及其甲醇 水(V∶V=70∶30)混合溶液在不同pH值下的反应速率常数,并求出了异丙酚氧化反应的活化能,结果表明pH值与温度对异丙酚的氧化动力学均有影响 相似文献