全文获取类型
收费全文 | 44537篇 |
免费 | 4272篇 |
国内免费 | 1739篇 |
专业分类
耳鼻咽喉 | 584篇 |
儿科学 | 869篇 |
妇产科学 | 918篇 |
基础医学 | 5507篇 |
口腔科学 | 1166篇 |
临床医学 | 4718篇 |
内科学 | 7508篇 |
皮肤病学 | 925篇 |
神经病学 | 2982篇 |
特种医学 | 1360篇 |
外国民族医学 | 16篇 |
外科学 | 5804篇 |
综合类 | 5101篇 |
现状与发展 | 5篇 |
一般理论 | 20篇 |
预防医学 | 2717篇 |
眼科学 | 1488篇 |
药学 | 3827篇 |
25篇 | |
中国医学 | 1438篇 |
肿瘤学 | 3570篇 |
出版年
2024年 | 82篇 |
2023年 | 583篇 |
2022年 | 1266篇 |
2021年 | 1892篇 |
2020年 | 1398篇 |
2019年 | 1453篇 |
2018年 | 1599篇 |
2017年 | 1406篇 |
2016年 | 1381篇 |
2015年 | 1883篇 |
2014年 | 2306篇 |
2013年 | 2265篇 |
2012年 | 3229篇 |
2011年 | 3323篇 |
2010年 | 2083篇 |
2009年 | 1688篇 |
2008年 | 2396篇 |
2007年 | 2392篇 |
2006年 | 2324篇 |
2005年 | 2247篇 |
2004年 | 1728篇 |
2003年 | 1465篇 |
2002年 | 1291篇 |
2001年 | 1021篇 |
2000年 | 1010篇 |
1999年 | 971篇 |
1998年 | 554篇 |
1997年 | 487篇 |
1996年 | 377篇 |
1995年 | 358篇 |
1994年 | 312篇 |
1993年 | 247篇 |
1992年 | 390篇 |
1991年 | 382篇 |
1990年 | 364篇 |
1989年 | 328篇 |
1988年 | 278篇 |
1987年 | 252篇 |
1986年 | 236篇 |
1985年 | 175篇 |
1984年 | 131篇 |
1983年 | 87篇 |
1982年 | 59篇 |
1981年 | 66篇 |
1979年 | 85篇 |
1978年 | 59篇 |
1977年 | 66篇 |
1974年 | 72篇 |
1973年 | 61篇 |
1972年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
D Schiffer L Autilio-Gambetti A Chiò P Gambetti M T Giordana F Gullotta A Migheli M C Vigliani 《Journal of neuropathology and experimental neurology》1991,50(4):463-473
Several neurodegenerative diseases, including motor neuron disease (MND), are characterized by formation of abnormal cytoskeleton-derived inclusions which contain ubiquitin (Ubq). We have studied the distribution of Ubq in 26 cases of MND with light and electron microscopic immunocytochemistry. Ubiquitin-positive inclusions were found in neurons of anterior horns in most cases of amyotrophic lateral sclerosis (ALS) but were not present in other forms of MND. Ubiquitin immunoreactivity was observed in 10-15 nm intraneuronal filaments, which were not stained by antibodies to neurofilaments, and on dense bodies of dystrophic neurites throughout the neuropil of anterior horns and pyramidal tracts. Data analysis showed a trend toward lower percentage of Ubq-positive neurons in cases with longer duration of illness or lower number of neurons. A high percentage of Ubq-positive inclusions occurred in cases with an aggressive clinical course, suggesting that ubiquitination takes place at early stages of the disease. 相似文献
82.
Jim-Shoung Lai T.-N. Wu Saou-Hsing Liou Chen-Yang Shen Chiam-Fang Guu Kquei-Nu Ko Chi. Hsueh-Yun P.-Y. Chang 《International archives of occupational and environmental health》1997,69(4):295-300
Objective: To examine the relationship between ambient lead levels and blood lead levels and to explore the modifiers of the relationship
between ambient lead and blood lead. Method: A cross-sectional study was conducted in two lead battery factories. Blood lead level and ambient lead concentration were
measured for each participant concurrently. A structured questionnaire was administered to collect sociodemographic characteristics
and occupational history. Design: Biological and personal environmental measurements of 219 lead-exposed workers were analyzed by both simple and multiple linear
regression. A regression model was selected for interpretation. Results: A high correlation (r=0.62) between ambient lead (PbA) and blood lead (PbB) was observed. In addition, numerous factors, including age, sex, alcohol
consumption, personal hygiene practice and type of lead exposure, were also found to influence blood lead levels. Although
PbB was highly correlated with PbA, blood lead level may not be effectively lowered by reducing ambient lead level. Based
on the regression coefficients, improvement of hygienic practice was more effective at lowering PbB than reducing ambient
lead level. Good hygienic practice may be the preferential way to reduce lead exposure in current conditions. Conclusion: Education of correct work practice may be more important than engineering control in the developing countries to lower blood
lead levels in lead battery factories.
Received: 28 May 1996/Accepted: 30 August 1996 相似文献
83.
84.
Camphor and m-cresol mixtures are used in antiseptic and anti-itching creams. No compendial method exists for these preparations. This paper reports a capillary gas chromatographic method using FID detection with 2,6-di-tert-butyl-4-methylphenol as internal standard on a 30 m×0.32 mm Supelcowax®-10 column (0.25 μm film) with helium as carrier gas. Ramped temperature programming was applied. The method allows simultaneous quantitation of camphor and m-cresol in the presence of o- and p-cresols, calamine and zinc oxide. Overall percent recoveries (±SD, n=9) of camphor, o-, p- and m-cresol from spiked placebo creams, at a labeled amount of 10 (w/w)% were 96.9±0.6, 98.2±0.6, 99.2±0.5 and 101.0±0.9%, respectively, and at a labeled amount of 1% were 96.7±0.6, 97.8±0.9, 97.8±0.6, and 100.3±1.0%, respectively. The recovery studies were carried out at ±30% of the labeled amounts. Linear peak area or height ratios were obtained (r>0.999) for camphor, o-, p- and m-cresol covering a concentration range of 10–200% of the labeled amount. Linearity (r>0.999) was also obtained for m-cresol when the relative concentration of o- and p-cresol was varied from 5 to 100% of the m-cresol concentration. The resolution between the ‘critical pair’ of p- and m-cresol was ≥1.1. The limit of quantitation was 23 pg for m-cresol and 9.3 pg for camphor using an injection split of 1:50. The repeatability (%RSD) for all compounds were <2% for peak area and <1.4% for peak height ratios. System suitability and robustness of the method were established. The method was successively applied to the assay of available commercial products and allows assay of camphor and the three cresol isomers. 相似文献
85.
目的 对比观察头孢噻肟(CTX)与其他两种抗菌药物治疗方案对30例血液病合并感染患者杀 菌活性(SBA)及临床疗效。方法SBA采用微量稀释法测定,临床疗效根据临床治疗登记表按三 级标准判定。结果与结论 头孢噻肟的临床反应最佳,杀菌作用时间维持较长,但对绿脓假单胞 菌和阴沟肠杆菌杀菌作用较差;呱拉西林(PIP)与阿米卡星(AN)方案的抗菌谱广,但PIP杀菌 作用时间较短,可考虑缩短给药间期,而AN可按一日一次给全日量的方案,以提高疗效减少不 良反应;头孢哌酮(CPZ)可主要用于绿脓假单胞菌感染,也可用于其它细菌的混合感染,但给药 间隔时间以一日三次为宜。 相似文献
86.
87.
U Tan 《The International journal of neuroscience》1992,66(3-4):177-188
The relation of right and left brain weight to right minus left (R-L) brain weight and the relation of R-L paw use to brain weight were studied in adults cats. The R-L brain weight was significantly larger than zero in right-pawed (RH) male and left-pawed (LH) females. The R-L brain weight was significantly smaller than zero in LH males, not significantly different from zero in RH females. The R-L brain weight was negatively linearly correlated with the left-brain weight in RH and LH males (no significant correlations in females). The R-L paw use showed a significant positive linear correlation with the R-L brain weight in RH male and females. There was a significant negative linear correlation between R-L paw use and R-L brain weight especially in LH males. Total brain weight showed a significant negative linear correlation with R-L paw use in RH males, and a positive linear correlation in LH males (no correlations in female cats). These results indicated that intermanual difference in paw use is associated with interhemispheric weight difference and total brain weight, especially in male cats; the left brain seems to be of importance in cerebral lateralization. 相似文献
88.
89.
Bilateral horizontal gaze palsies are rare. In this case report, we present a 28-year-old woman with bilateral horizontal gaze palsies due to involvement of both paramedian pontine reticular formations (PPRFs) by multiple sclerosis (MS) plaques. 相似文献
90.
目的 评价一种可提高肝细胞纯度和存活率的分离培养方法。方法 以体外两步胶原酶灌流法分离肝细胞,然后将其分成两组,对照组在接种培养前不经进一步处理,试验组则在应用适宜的Percoll梯度液离心纯化之后再行培养。藉台盼蓝拒染法比较两组肝细胞的存活率,采用MTT法动态比较两组肝细胞的增殖状态,在相差显微镜下观察细胞的纯度和形态。结果 未经进一步纯化处理的猪肝细胞存活率为90%±5%,鼠肝细胞存活率为80%±5%,两者纯度均约90%;经Percoll梯度液离心纯化后,其高活力肝细胞比率均提高至98%±2%,纯度可达99%以上。从开始接种到大部分肝细胞贴壁生长,试验组比对照组肝细胞的时间有所缩短。结论 用Percoll梯度液纯化新分离肝细胞,可提高肝实质细胞的活力与纯度。 相似文献