全文获取类型
收费全文 | 20389篇 |
免费 | 947篇 |
国内免费 | 137篇 |
专业分类
耳鼻咽喉 | 157篇 |
儿科学 | 415篇 |
妇产科学 | 193篇 |
基础医学 | 2392篇 |
口腔科学 | 419篇 |
临床医学 | 1259篇 |
内科学 | 5311篇 |
皮肤病学 | 346篇 |
神经病学 | 1549篇 |
特种医学 | 659篇 |
外科学 | 3736篇 |
综合类 | 72篇 |
预防医学 | 432篇 |
眼科学 | 385篇 |
药学 | 1492篇 |
中国医学 | 52篇 |
肿瘤学 | 2604篇 |
出版年
2023年 | 94篇 |
2022年 | 180篇 |
2021年 | 382篇 |
2020年 | 184篇 |
2019年 | 291篇 |
2018年 | 348篇 |
2017年 | 252篇 |
2016年 | 376篇 |
2015年 | 408篇 |
2014年 | 507篇 |
2013年 | 687篇 |
2012年 | 1124篇 |
2011年 | 1147篇 |
2010年 | 690篇 |
2009年 | 558篇 |
2008年 | 1143篇 |
2007年 | 1191篇 |
2006年 | 1224篇 |
2005年 | 1258篇 |
2004年 | 1219篇 |
2003年 | 1232篇 |
2002年 | 1259篇 |
2001年 | 568篇 |
2000年 | 511篇 |
1999年 | 521篇 |
1998年 | 324篇 |
1997年 | 270篇 |
1996年 | 229篇 |
1995年 | 213篇 |
1994年 | 206篇 |
1993年 | 196篇 |
1992年 | 277篇 |
1991年 | 275篇 |
1990年 | 235篇 |
1989年 | 243篇 |
1988年 | 187篇 |
1987年 | 182篇 |
1986年 | 154篇 |
1985年 | 163篇 |
1984年 | 118篇 |
1983年 | 107篇 |
1982年 | 64篇 |
1981年 | 54篇 |
1980年 | 58篇 |
1979年 | 77篇 |
1978年 | 48篇 |
1977年 | 47篇 |
1974年 | 42篇 |
1972年 | 42篇 |
1971年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
51.
T Ohashi F Yamamoto H Yamamoto H Ichikawa T Shibata Y Shimada T Ishikawa K Kagisaki Y Kumada Y Kawashima 《[Zasshi] [Journal]. Nihon Kyōbu Geka Gakkai》1992,40(11):1998-2004
The effects of potassium in reperfusion solution (RS) and the influence of sodium on this effect were studied. Experimental time course was as followed: 20 min working perfusion, 3 min cardioplegic infusion with St. Thomas Cardioplegic Solution followed by global ischemia for 33 or 35 min at 37.5 degrees C, 15 min early Langendorff reperfusion with several different potassium concentration modified with Krebs Henseleit Bicarbonate Buffer (KHBB) containing 145 mM and 110 mM sodium and 5 min late reperfusion with KHBB, followed by 20 min working perfusion. Potassium in RS possessed bell shaped dose response nature with optimal concentration of 10 mM in the condition of 145 mM sodium but 6 m in the condition of 110 mM in terms of percent recovery of aortic flow. Although higher potassium reperfusion produced less Creatine Kinase leakage. 相似文献
52.
Yoichi Sato Hitoshi Yokoyama Masaaki Watanabe Osami Hamada 《Annals of thoracic and cardiovascular surgery》2003,9(6):401-405
A 74-year-old man with combined valvular disease with a recent cerebral infarction was admitted. While undergoing thorough examination for valvular disease, absent right superior vena cava (RSVC) and persistent left superior vena cava (PLSVC) were recognized. Chest X-ray film suggested a right arch protrusion, and CT and venogram confirmed the diagnosis. During surgery, replacement of the mitral and aortic valves and annuloplasty of the tricuspid valve were performed. A blood draining cannula was inserted in retrograde fashion from the coronary sinus into the PLSVC, without any difficulties in the tricuspid valve repair. Due to bradycardic atrial fibrillation, we believed that it would be difficult to insert an endocardial electrode postoperatively, hence myocardial electrode was placed in the right ventricular wall. Absent RSVC combined with PLSVC is very rare, and a patient who underwent combined valve surgery with this rare anatomical abnormality is herein presented. 相似文献
53.
H Yamazaki Y Oda Y Funae S Imaoka Y Inui F P Guengerich T Shimada 《Carcinogenesis》1992,13(6):979-985
The possible roles of cytochrome P450 (P450) enzymes in the metabolic activation of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) by rat liver microsomes have been examined in a system containing the bacterial tester strain Salmonella typhimurium NM2009, a newly developed strain showing high O-acetyltransfer activities. The DNA-damaging activity could be determined by measuring expression of the umu gene in a plasmid containing the fused umuC-lacZ gene construct in the bacteria. The following lines of evidence support the view that both NDMA and NDEA are principally oxidized to reactive products by P450 2E1 in rat liver microsomes. First, NDMA and NDEA were activated by rat liver microsomes in a protein- and substrate-dependent manner and the former chemical was more active than the latter; both activities were induced in rats treated with P450 2E1 inducers such as ethanol, acetone and isoniazid and by starvation. Second, activation of NDMA and NDEA were both inhibited significantly by antibodies raised against rat P450 2E1 and by P450 2E1 inhibitors such as diethyldithiocarbamate and 4-methylpyrazole in rat liver microsomes. Finally, in reconstituted monooxygenase systems containing purified rat P450 enzymes, P450 2E1 gave the highest rates of the activation of both NDMA and NDEA; the addition of rabbit cytochrome b5 to the system caused about a 1.5-fold increase in both reactions. In separate experiments we also found that N-nitrosomethylacethoxymethylamine, a compound that reacts with DNA after ester cleavage, is more genotoxic in S.typhimurium NM2009 than in S.typhimurium NM2000, a strain that is defective in O-acetyltransferase activity. Part of the pathway involved in the activation of nitrosamines is suggested to be acetylation of alkyldiazohydroxides formed by P450 or acetylesterase, because the genotoxic activity of N-nitrosomethylacethoxymethylamine in S.typhimurium NM2009 could be inhibited by the O-acetyltransferase inhibitor pentachlorophenol. These results indicate that NDMA and NDEA are oxidized to gentoxoic products by rat liver microsomes and that a P450 2E1 enzyme plays a major role in the activation of these two potent carcinogens. The activation pathway of N-nitrosodialkylamines through acetylation by O-acetyltransferase has been proposed. This simple bacterial system for measuring genotoxicity should facilitate studies on the activation of N-nitroso alkylamines. 相似文献
54.
55.
56.
Hideyuki Iwai Ryuji Koike Jun Ogawa Takahiko Sugihara Hiroyuki Hagiyama Kenji Nagasaka Yoshinori Nonomura Junko Nishio Toshihiro Nanki Rieko Tsubata Hitoshi Kohsaka Tetsuo Kubota Nobuyuki Miyasaka 《Nihon Rinshō Men'eki Gakkai kaishi》2002,25(3):270-276
A 36-year-old man was admitted to a hospital with complaints of fever, polyarthralgia and dyspnea. Erythema was observed on his face, extensor surface of the fingers and extremities, and a chest X-ray revealed massive bilateral pleural effusion. He had no sign of myopathy at this point. Pleural fluid was proved to be exudative and contained extremely high levels of hyaluronic acid. He was also complicated with interstitial pneumonitis and was given a pulse therapy with methyl prednisolone followed by daily administration of 55 mg prednisolone (PSL). Twenty days after the commencement of the therapy, pleural effusion decreased but muscle weakness gradually appeared, accompanied by elevation of myogenic enzymes. Myogenic changes on electromyogram, and irregularity of the muscle fibers with slight inflammatory cell infiltrates in a biopsy specimen were demonstrated. He was transferred to our hospital, and a diagnosis of dermatomyositis was made. Later, pleural effusion waxed and waned depending on the dosage of PSL, but no other causative disorder was demonstrated by extensive examinations. This case indicates that the pleuritis could be one of the vasculitic manifestations of dermatomyositis. 相似文献
57.
58.
59.