全文获取类型
收费全文 | 18359篇 |
免费 | 1420篇 |
国内免费 | 564篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 449篇 |
妇产科学 | 247篇 |
基础医学 | 3576篇 |
口腔科学 | 158篇 |
临床医学 | 1202篇 |
内科学 | 4164篇 |
皮肤病学 | 130篇 |
神经病学 | 1737篇 |
特种医学 | 290篇 |
外国民族医学 | 1篇 |
外科学 | 1309篇 |
综合类 | 1948篇 |
现状与发展 | 3篇 |
一般理论 | 1篇 |
预防医学 | 1872篇 |
眼科学 | 110篇 |
药学 | 1640篇 |
6篇 | |
中国医学 | 720篇 |
肿瘤学 | 740篇 |
出版年
2024年 | 56篇 |
2023年 | 337篇 |
2022年 | 578篇 |
2021年 | 870篇 |
2020年 | 718篇 |
2019年 | 700篇 |
2018年 | 704篇 |
2017年 | 603篇 |
2016年 | 683篇 |
2015年 | 738篇 |
2014年 | 1227篇 |
2013年 | 1269篇 |
2012年 | 1085篇 |
2011年 | 1217篇 |
2010年 | 1011篇 |
2009年 | 1025篇 |
2008年 | 1043篇 |
2007年 | 908篇 |
2006年 | 738篇 |
2005年 | 572篇 |
2004年 | 485篇 |
2003年 | 339篇 |
2002年 | 296篇 |
2001年 | 256篇 |
2000年 | 230篇 |
1999年 | 179篇 |
1998年 | 184篇 |
1997年 | 152篇 |
1996年 | 176篇 |
1995年 | 150篇 |
1994年 | 121篇 |
1993年 | 143篇 |
1992年 | 121篇 |
1991年 | 101篇 |
1990年 | 92篇 |
1989年 | 107篇 |
1988年 | 115篇 |
1987年 | 68篇 |
1986年 | 80篇 |
1985年 | 99篇 |
1984年 | 123篇 |
1983年 | 60篇 |
1982年 | 110篇 |
1981年 | 79篇 |
1980年 | 82篇 |
1979年 | 76篇 |
1978年 | 46篇 |
1977年 | 45篇 |
1976年 | 57篇 |
1975年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
Many new insights have been gained over the past 5 years into the mechanisms that regulate immune reactivity to cell and organ transplants. This new knowledge is being applied to the development of innovative experimental strategies that may soon be evaluated in the clinic. 相似文献
14.
Gene expression regulation and cancer 总被引:1,自引:0,他引:1
15.
Oral administration of an edible-mushroom-derived protein inhibits the development of food-allergic reactions in mice 总被引:5,自引:0,他引:5
K.-Y. Hsieh C.-I. Hsu† J.-Y. Lin† C.-C. Tsai‡ R.-H. Lin§ 《Clinical and experimental allergy》2003,33(11):1595-1602
BACKGROUND: Food allergy is a common disease without effective treatment. Since strict elimination of food allergens may be difficult, strategies for effective intervention are urgently needed. OBJECTIVE: The aim was to investigate the prophylactic use of orally administrated FIP-fve, an immunomodulatory protein isolated from the edible mushroom Flammulina velutipes, in a murine model of food allergy. METHODS: BALB/c mice were immunized twice intraperitoneally with ovalbumin (OVA), at an interval of 2 weeks. Before and during each period of immunization, FIP-fve (200 microg per mouse) or phosphate-buffered saline was given orally every other day with a total of five doses. Then OVA-specific antibodies and cytokine profiles were determined. Subsequently, the mice were orally challenged with OVA. Symptoms of anaphylaxis, levels of plasma histamine, and histology of intestines were examined. RESULTS: Mice receiving oral FIP-fve treatment during sensitization to OVA had an impaired OVA-specific IgE response with a Th1-predominant cytokine profile. These mice were protected from systemic anaphylaxis-like symptoms induced by subsequent oral challenge with OVA. CONCLUSION: Oral administration of FIP-fve has a Th1-skewing effect on the development of the allergen-specific immune response, and may serve the purpose of immunoprophylaxis for food allergy and other allergic diseases. 相似文献
16.
17.
R. Bendayan G. Kennedy R. C. Frecker E. M. Sellers 《European journal of clinical pharmacology》1993,44(1):51-55
Summary The efficacy of cimetidine as a treatment that could reduce smoking in heavily dependent smokers has been determined. In a randomised, double-blind, double-crossover experiment, 43 heavy smokers were divided into two groups, one receiving cimetidine 400 mg orally three times a day, and the other receiving placebo for two weeks followed by the alternative treatment (placebo or cimetidine).No significant difference in the mean alveolar carbon monoxide, nicotine or cotinine levels was found between the two treatment groups compared to baseline. Since the alveolar carbon monoxide level reflects the intensity of smoking behaviour, the results suggest that no change in smoking behaviour occurred in the subjects.Contrary to our previous findings that cimetidine decreased the total body clearance of nicotine by 30% in a population of non-smokers, in the heavily dependent smokers, cimetidine did not appear to alter nicotine elimination. One possible explanation for the discrepancy is that tobacco smoking is known to induce nicotine metabolism and the induction might have offset any effect of cimetidine on nicotine elimination.Cimetidine does not appear to be a useful treatment leading to a reduction or cessation of cigarette smoking. 相似文献
18.
Hiroshi Uno Yoshihiro Izawa Kiyoshi Sagara Tamotsu Koyama Tokutaro Makita Chia-Yuan Hsu-Chang Mitsugi Sugiyama 《Journal of bone and mineral metabolism》1990,8(1):10-16
The effect of 1α-hydroxyvitamin D3 (1α(OH)D3) on the metabolic bone disorders developed in gastrectomized rats were investigated biochemically and histomorphologically.
1α(OH)D3 was suspended in 0.2 % Triton-X-100 aqueous solution after dissolving in a very small amount of ethanol, was given orally
to the rats for 10 weeks. The sham operated animals and the gastrectomy control animals received the vehicle alone. Gastrectomy
was followed by the development of the metabolic bone disorders after 10 weeks of observation. This was characterized by reduction
in ash content of the femur and histologically by a disappearance of the trabecular bone in tibial metaphysis. Decrease Ca
absorption from the intestines was demonstrated by a radiotracer technique. Biochemical studies showed significant decreases
in serum 25(OH)D concentration in gastrectomized rats. These findings suggest that gastrectomy partially impairs intestinal
absorption of calcium and results in a negative calcium balance, which may contribute to the development of bone metabolic
disorders in rats. The administration of 1α(OH)D3 increased dose-dependently serum calcium and Ca absorption from the intestine and prevented the development of bone metabolic
disorders histomorphologically. 相似文献
19.
白细胞介素-10诱导的大鼠树突状细胞体外免疫功能的研究 总被引:19,自引:7,他引:12
目的 研究白细胞介素 10 (IL 10 )诱导的大鼠未成熟树突状细胞 (imDCs)体外诱导免疫耐受的可行性。方法 在经典诱导方案的基础上 ,应用IL 10 ( 10 μg/L)抑制大鼠骨髓来源DCs的成熟 (IL 10组 ,10例 ) ,并设对照组 (IL 4组 ,10例 )。培养期间观察DCs形态 ,检测DCs表型、摄取抗原能力、体外免疫功能及培养上清细胞因子水平。结果 与IL 4组比较 ,IL 10组DCs细胞表面CD80 、CD86及OX6低度表达 ( 2 5 .3 %、42 .4%、3 2 .3 % ) ,吞噬能力较强 ( 81.9) ,刺激同种异体淋巴细胞增殖能力下降 ,该淋巴细胞具有抗原特异性低反应性 ;培养上清中IL 12水平 ( 4 0 6.5pg/L)及初次MLR培养上清IL 2水平 ( 2 45 .4ng/L)均较低 ,差异有非常显著性 (P <0 .0 1)。 结论 IL 10作用的大鼠imDCs具有诱导免疫耐受的应用价值。 相似文献
20.
Acetylcholinesterase Adaptation to Voluntary Wheel Running is Proportional to the Volume of Activity in Fast, but not Slow, Rat Hindlimb Muscles 总被引:4,自引:0,他引:4
Victor Gisiger Manon Bélisle Phillip F. Gardiner 《The European journal of neuroscience》1994,6(5):673-680
Chronic enhancement of neuromuscular activity by forced exercise training programmes results in selective adaptation of the G4 acetylcholinesterase (AChE) molecular form in hindlimb fast muscles of the rat, with only minor and non-selective AChE changes in the soleus. In order to shed further light on the physiological significance of this G4 adaptation to training, we turned to a voluntary exercise model. The impact of 5 days and 4 weeks of voluntary wheel cage running on AChE molecular forms was examined in four hindlimb fast muscles and the slow-twitch soleus from two rat strains. Inbred Fisher and Sprague– Dawley rats, placed in live-in wheel cages, exercised spontaneously for distances which progressively increased up to an average of ∼3 and 18 km/day, respectively, by the end of week 4. Fast muscles responded to this voluntary activity by massive G4 increases (up to 420%) with almost no changes in A12 , so that by week 4 the tetramer became the main AChE component of these muscles. The additional G4 was composed primarily of amphiphilic molecules, suggesting a membrane-bound state. The G4 content of fast muscles was highly correlated with the distance covered by the rats during the 5 days before they were killed ( r = 0.850-0.879, P < 0.001 in three muscles). The soleus muscle, in turn, responded to wheel cage activity by a marked selective reduction of its asymmetric forms—up to 45% for A12 . This A12 decline, already maximal by day 5 of wheel cage running, showed no relationship with the distance covered. The present results constitute strong new evidence suggesting that the role of AChE in neuromuscular transmission is not limited solely to the rapid inactivation of just-released acetylcholine. 相似文献