全文获取类型
收费全文 | 36235篇 |
免费 | 1944篇 |
国内免费 | 137篇 |
专业分类
耳鼻咽喉 | 440篇 |
儿科学 | 2153篇 |
妇产科学 | 709篇 |
基础医学 | 4604篇 |
口腔科学 | 820篇 |
临床医学 | 2552篇 |
内科学 | 7362篇 |
皮肤病学 | 851篇 |
神经病学 | 1910篇 |
特种医学 | 852篇 |
外科学 | 4997篇 |
综合类 | 1378篇 |
一般理论 | 15篇 |
预防医学 | 2113篇 |
眼科学 | 1543篇 |
药学 | 3525篇 |
中国医学 | 274篇 |
肿瘤学 | 2218篇 |
出版年
2023年 | 237篇 |
2022年 | 670篇 |
2021年 | 1160篇 |
2020年 | 637篇 |
2019年 | 857篇 |
2018年 | 1046篇 |
2017年 | 721篇 |
2016年 | 956篇 |
2015年 | 996篇 |
2014年 | 1357篇 |
2013年 | 1753篇 |
2012年 | 2413篇 |
2011年 | 2433篇 |
2010年 | 1393篇 |
2009年 | 1250篇 |
2008年 | 1781篇 |
2007年 | 1757篇 |
2006年 | 1780篇 |
2005年 | 1392篇 |
2004年 | 1392篇 |
2003年 | 1180篇 |
2002年 | 1007篇 |
2001年 | 829篇 |
2000年 | 871篇 |
1999年 | 735篇 |
1998年 | 338篇 |
1997年 | 248篇 |
1996年 | 250篇 |
1995年 | 235篇 |
1994年 | 189篇 |
1993年 | 168篇 |
1992年 | 503篇 |
1991年 | 404篇 |
1990年 | 434篇 |
1989年 | 406篇 |
1988年 | 362篇 |
1987年 | 363篇 |
1986年 | 351篇 |
1985年 | 336篇 |
1984年 | 265篇 |
1983年 | 223篇 |
1982年 | 144篇 |
1979年 | 230篇 |
1978年 | 152篇 |
1977年 | 182篇 |
1975年 | 174篇 |
1974年 | 182篇 |
1973年 | 182篇 |
1972年 | 173篇 |
1971年 | 161篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Aminophylline, a bronchodilator, was considered a suitable drug for targeting to the lung to treat emphysema. Factorial concept was utilized to optimize the size and drug loading of microspheres suitable for targeting. Aminophylline-loaded albumin microspheres were prepared by heat denaturation adjusting the manufacturing variables, namely albumin concentration, drug concentration, water-oil phase ratio and stirring rate at low and high levels. For two levels of the four variables the experimentation was performed in 16 batches. A good yield of well-defined microspheres of the size range, 2-30 microns, were obtained from all the batches. The drug loading was found maximum (36.33 per cent) in batch XV of microspheres prepared with low albumin concentration, high drug concentration, low water-oil phase ratio and low stirring rate. The least number (13 per cent) of microspheres of batch XV were below 7 microns and the remaining 87 per cent were above this size. Considering the payload and size, microspheres of batch XV were found suitable for targeting to the lung. 相似文献
82.
83.
M Noguchi T Kodama Y Shimosato T Koide T Naruke G Singh S L Katyal 《The American journal of surgical pathology》1986,10(2):134-139
A case of papillary adenoma of type 2 pneumocytes is reported. A 57-year-old man had an unusual coin lesion in the periphery of the right lung without any symptoms. When detected in a mass survey examination, it was approximately 1.5 cm in diameter, well circumscribed, and located in S4, involving the sixth-order bronchus of B4. Light-microscopic examination revealed cuboidal tumor cells arranged in a papillary pattern. Ultrastructurally, the cells had characteristic osmiophilic lamellar bodies. By immunoperoxidase staining, the tumor cells were shown to have intracytoplasmic surfactant apoproteins. The postoperative course was uneventful, and there is no evidence of disease 8 years later. 相似文献
84.
The relationship between stressful family life events and somatic complaints in 477 school children was studied. There was a significant association between life events and somatic complaints, with a general trend for somatic complaints to increase in almost direct proportion to the number of family life events. Overall occurrence of these nonspecific symptoms was more in girls. The somatic complaints were significantly more in children from nuclear families and of illiterate or poorly educated mothers. No significant association was observed between somatic complaints and number of children in the family or socio-economic status. Assessment of psychodevelopmental tasks and family environment during routine check up of children by the school health teams and their appropriate training in this field should be stressed upon. 相似文献
85.
Earlobe reconstruction using a Limberg flap in six ears. 总被引:2,自引:0,他引:2
Many methods of earlobe reconstruction using one or two stages have been described. These have used (i) the superimposition of two flaps, (ii) a single flap lined with a skin graft or (iii) doubled-over single or bilobed flaps. We present a new method of earlobe reconstruction using a doubled-over Limberg flap, which we have used in six ears. This produces a good-looking earlobe, which needs defatting after 3-4 months and suffered minimal necrosis at the tip of the folded flap in three cases. There was no earlobe shrinkage on long-term follow-up. 相似文献
86.
H S Watson E O Singh M R Hermans K S Coffield G T Keegan 《The Journal of urology》1992,147(3):689-691
We report a case of eosinophilic cystitis that was responsive to prednisone but that recurred when the drug was withdrawn. The cause of eosinophilic cystitis remains an enigma but it probably represents a form of allergy. Investigation of etiology and therapeutic options are discussed. 相似文献
87.
Our data suggest that DOX resistance in P388/R-84 cells may result, at least in part, from reduced free radical formation by both suppression of flavin reductase(s) and overexpression of certain antioxidant enzymes such as GSH peroxidase and catalase. In addition, our results, in conjunction with other studies, indicate that flavin reductase(s) and antioxidant enzymes are differentially altered in cancer cells with acquired or de novo resistance to DOX. Further studies are needed, however, to elucidate the mechanism(s) by which the gene expression of these enzymes is regulated in drug-sensitive and -resistant cells. 相似文献
88.
89.
90.
The antiadrenergic actions of amiodarone (Am) are well known but its effect and that of its metabolite, desethylamiodarone (DAm), on beta-receptor density (Bmax) and affinity (KD) are poorly defined. Thus, the acute and chronic effects of Am and DAm on myocardial beta-receptors in rabbits were determined relative to changes in thyroid hormones and serum and tissue drug concentrations. Bmax and KD were measured by radio-ligand binding, thyroid hormones by RIA, and drug levels by HPLC. Compared with controls, intravenous Am (20 mg/kg) reduced Bmax by 23% (p less than 0.05) and DAm (20 mg/kg) by 32% (p less than 0.05). After 3 weeks of chronic drug, the corresponding value for Am was 24% (p less than 0.05) versus 45% (p less than 0.05) for DAm. The effect of DAm was significantly greater (p less than 0.05) than that of Am, being comparable to that of Am (-44%) after 6 weeks. In the case of Am, doubling the dose (and myocardial level) led to no further decrease in Bmax. DAm also reduced Bmax more following chronic treatment than after acute administration (-45 versus -32%), a difference of borderline significance. Following 3 weeks of p.o. Am, T3 decreased 3% (NS) and reverse T3 (rT3) increased 90% (p less than 0.05); after 6 weeks, the corresponding values were 25% (p less than 0.05) and 181% (p less than 0.01). After 1 week of p.o. DAm, T3 did not change but rT3 increased by 34% (p less than 0.05); after 3 weeks the corresponding values were 21% (p less than 0.01) and 64% (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献