全文获取类型
收费全文 | 16502篇 |
免费 | 845篇 |
国内免费 | 116篇 |
专业分类
耳鼻咽喉 | 352篇 |
儿科学 | 254篇 |
妇产科学 | 167篇 |
基础医学 | 1814篇 |
口腔科学 | 336篇 |
临床医学 | 972篇 |
内科学 | 4394篇 |
皮肤病学 | 265篇 |
神经病学 | 1536篇 |
特种医学 | 563篇 |
外科学 | 2794篇 |
综合类 | 60篇 |
预防医学 | 373篇 |
眼科学 | 329篇 |
药学 | 1140篇 |
中国医学 | 71篇 |
肿瘤学 | 2043篇 |
出版年
2023年 | 84篇 |
2022年 | 165篇 |
2021年 | 404篇 |
2020年 | 249篇 |
2019年 | 314篇 |
2018年 | 426篇 |
2017年 | 309篇 |
2016年 | 387篇 |
2015年 | 408篇 |
2014年 | 505篇 |
2013年 | 622篇 |
2012年 | 956篇 |
2011年 | 1074篇 |
2010年 | 582篇 |
2009年 | 478篇 |
2008年 | 863篇 |
2007年 | 992篇 |
2006年 | 923篇 |
2005年 | 958篇 |
2004年 | 932篇 |
2003年 | 947篇 |
2002年 | 917篇 |
2001年 | 372篇 |
2000年 | 314篇 |
1999年 | 294篇 |
1998年 | 176篇 |
1997年 | 162篇 |
1996年 | 142篇 |
1995年 | 124篇 |
1994年 | 128篇 |
1993年 | 107篇 |
1992年 | 233篇 |
1991年 | 211篇 |
1990年 | 181篇 |
1989年 | 209篇 |
1988年 | 158篇 |
1987年 | 141篇 |
1986年 | 114篇 |
1985年 | 117篇 |
1984年 | 75篇 |
1983年 | 84篇 |
1982年 | 44篇 |
1981年 | 42篇 |
1979年 | 56篇 |
1978年 | 41篇 |
1977年 | 38篇 |
1976年 | 37篇 |
1975年 | 42篇 |
1974年 | 42篇 |
1973年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Giovanni Manfredi Tuan Vu Eduardo Bonilla Eric A. Schon Salvatore DiMauro Enrica Arnaudo Lee Zhang Lewis P. Rowland Michio Hirano 《Annals of neurology》1997,42(2):180-188
We identified large-scale heteroplasmic mitochondrial DNA (mtDNA) rearrangements in a 50–year-old woman with an adult-onset progressive myopathy. The predominant mtDNA abnormality was a 21.2–kb duplicated molecule. In addition, a small population of the corresponding partially deleted 4.6–kb molecule was detected. Skeletal muscle histology revealed fibers that were negative for cytochrome c oxidase (COX) activity and had reduced mtDNA-encoded COX subunits. By single-fiber polymerase chain reaction analysis, COX-negative fibers contained a low number of wild-type or duplicated mtDNA molecules (ie, nondeleted). In situ hybridization demonstrated that the abnormal fibers contained increased amounts of mtDNA compared with normal fibers and that most of the genomes were deleted. We concluded that deleted mtDNA molecules were primarily responsible for the phenotype in this patient. 相似文献
82.
Clinical effects of percutaneous cardiopulmonary support in severe heart failure: early results and analysis of complications. 总被引:2,自引:0,他引:2
Shigeru Sakamoto Junichi Matsubara Toshiaki Matsubara Yasuhiro Nagayoshi Shinji Shono Hisateru Nishizawa Masaaki Kanno Katsunori Takeuchi Toshimichi Nonaka Jun Kyosawa 《Annals of thoracic and cardiovascular surgery》2003,9(2):105-110
Between January 1993 and December 2001, we employed percutaneous cardiopulmonary support (PCPS) in 35 patients. PCPS was used for postcardiotomy in 25 of these patients who could not be weaned from cardiopulmonary bypass (CPB) because of severe cardiogenic shock. In the other 10 patients, PCPS was used for a non-surgical disease. Twenty-nine patients (82.9%) were weaned from PCPS, and 28 (80.0%) survived. The other 7 patients (20.0%) died due to postoperative complications. The causes of death were multiple organ failure (MOF) due to wound bleeding, low cardiac output syndrome (LOS), myonephropathic metabolic syndrome (MNMS) with severe lower limbs ischemia, cerebrovascular accident (CVA), and sepsis. The first cause for the complications was postoperative sustained severe heart failure. To improve the survival rate, it was necessary to prevent bleeding and begin PCPS at an earlier stage. 相似文献
83.
Toshimichi Hasegawa Yuko Tazuke Yasuhiro Iwasaki Osamu Monta Junichi Sumimura Hiroshi Koyama Toru Dezawa 《Surgery today》1997,27(12):1191-1194
We report herein the case of a premature infant with esophageal atresia (EA) and a tracheoesophageal fistula (TEF) associated
with cardiac anomalies who was successfully treated by an early ligation of the TEF following gastrostomy, and delayed repair
of the esophagus. A 1212-g male was born prematurely at 31 gestational weeks, at which time he was diagnosed as having EA
with TEF and patent ductus arteriosus (PDA), ventricular septal defect (VSD), and atrial septal defect (ASD). A gastrostomy
was initially performed but following extubation he gradually became tachypneic. A chest roentogenogram revealed atelectasis
and ground-glass appearance, and reintubation was required. Ligation of the TEF was performed 53h after his birth. Following
the improvement of his respiratory condition through ventilatory support and the intratracheal administration of pulmonary
surfactant, he underwent repair of the esophagus on the 6th day of life. Postoperatively, he suffered from heart failure,
but was treated with peritoneal dialysis and pharmacological closure of the PDA. Weaning the infant from the ventilator proved
difficult, but it was finally achieved when he had reached a weight of 2268g at 3 months of age by enteral feeding. Our experience
of this case demonstrates that early ligation of TEF should be performed for a premature infant with EA and TEF before respiratory
distress syndrome (RDS) has developed. If a gastrostomy is required to prevent gastric distention, it should be followed by
simultaneous or immediate ligation of the TEF. 相似文献
84.
Cyclic adenosine monophosphate production and contractile response induced by beta-adrenoceptor subtypes in rabbit urinary bladder smooth muscle 总被引:1,自引:0,他引:1
T Morita S Dohkita S Kondo T Nishimoto S Hirano S Tsuchida 《Urologia internationalis》1990,45(1):10-15
The spontaneous contractile force of muscle strips isolated from male rabbit urinary bladder dome [detrusor) and base (trigonal muscle) was dose dependently inhibited by isoproterenol, a non-specific beta-adrenoceptor agonist. The relaxant response to 10(-6) M isoproterenol in the detrusor muscle was completely blocked by butoxamine (10(-4) M), a selective beta-2-antagonist, and by propranolol (10(-6) M), a non-specific beta-antagonist, but not by metoprolol (10(-6) to 10(-4) M), a selective beta-1-antagonist. Relaxation of trigonal muscle induced by 10(-6) M isoproterenol was inhibited 30% by metoprolol (10(-5) M), 70% by butoxamine (10(-4)M), and 100% by propranolol (10(-6) M). Terbutaline, a selective beta-2-adrenoceptor agonist, also caused dose dependently a relaxant response in detrusor and trigonal muscle. The maximum relaxant responses to isoproterenol and terbutaline were significantly greater in detrusor than in trigonal muscle. Dobutamine, a relatively specific beta-1-adrenoceptor agonist, caused a small but significant relaxant response in trigonal, but no change in detrusor muscle. In trigonal muscle the relaxant response to dobutamine was less than that to terbutaline. Cyclic adenosine monophosphate accumulation in detrusor did not significantly increase after administration of dobutamine, but significantly increased after administration of terbutaline. On the other hand, not only terbutaline, but also dobutamine, markedly increased cyclic adenosine monophosphate accumulation in trigonal muscle.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
85.
We investigated the effects of ultraviolet B (UVB) irradiation on the formation of ester forms of riboflavin and of high-molecular-weight (HMW) protein aggregates and on lenticular riboflavin-binding capacity (LRBC). Esterification of riboflavin decreased as the duration of UV irradiation increased, suggesting the irradiation-induced denaturation of the apoenzyme of synthetases of ester forms of riboflavin. UVB irradiation of lens homogenate supplemented with riboflavin increased LRBC and the formation of HMW protein aggregates, while gamma-crystallin was decreased. These results are consistent with those of our earlier studies in which we obtained data suggesting that, upon exposure of rat lens homogenate to fluorescent light, photosensitized riboflavin may bring about cross-linking of lens protein. Our data demonstrate that the photosensitivity of lenticular riboflavin is increased by longer periods of UV irradiation. 相似文献
86.
Summary In an autopsied case of a 37-year-old man with acquired immune deficiency syndrome (AIDS), multinucleated giant cell encephalopathy was noted in close proximity to multiple nodules of primary lymphoma of the brain. Some multinucleated giant cells and macrophages contained HTLV-III-like viral particles. Nuclear bridges, thin strands connecting individual nuclei with one another, were observed with both light and electron microscopes within some of the multinucleated giant cells. There were also thin tapering nuclear processes, which were probably part of nuclear bridges. The possibility that the nuclear bridges and processes represent amitotic nuclear division is discussed. 相似文献
87.
The metabolism of cadmium oxide (CdO, insoluble form) and cadmium chloride (CdCl2, soluble form) instilled intratracheally into the rat lung was investigated. CdO might be solubilized rapidly in the lung and consequently pulmonary clearance rate of CdO was not so different from that of CdCl2. At a dose of 5 micrograms Cd/rat about 20% of the dose was translocated to the liver within 12 h, whereas gradual and consistent accumulation of Cd was observed in the kidney up to 7 days. Both pulmonary clearance and translocation of Cd to the liver were accelerated with the dose of instilled CdO, however, Cd accumulated in the kidney was proportional to the dose. Lung weight was increased by the instillation of CdO. Lung essential elements such as S, P, Mg, Zn and Mn were not affected in the inflammatory-reparative proliferative process, but Cu content of unit lung weight was slightly decreased. 相似文献
88.
89.
90.
Clinical similarities of hereditary progressive/dopa responsive
dystonia caused by different types of mutations in the GTP
cyclohydrolase I gene 下载免费PDF全文
Y. Tamaru M. Hirano H. Ito J. Kawamura S. Matsumoto T. Imai S. Ueno 《Journal of neurology, neurosurgery, and psychiatry》1998,64(4):469-473
OBJECTIVE—Hereditary progressive dystonia withpronounced diurnal fluctuation ((HPD)/dopa responsive dystonia (DRD))is a childhood onset dystonia which responds to levodopa. Variousclinical signs and symptoms of HPD/DRD have been recognised to date.Mutations in the GTP cyclohydrolase I (GTP-CH-I) gene were recentlyidentified as the cause of HPD/DRD. In the present study, the GTP-CH-Igene and the clinical features of eight HPD/DRD patients from sixfamilies were analysed to determine the correlationsbetween clinical expression and the mutations in the GTP-CH-I gene.
METHODS—The exons, exon-intron junctions, and anindispensable part of the 5' flanking region of the GTP-CH-I gene weresequenced in the eight clinically diagnosed patients with HPD/DRD andtheir asymptomatic parents.
RESULTS—Three independent mutations in theGTP-CH-I gene were found in three patients. One of the patients and herasymptomatic mother were heterozygous for a novel mutation at theinitiation codon. The three patients with dissimilar GTP-CH-I mutationsexhibited similar clinical features. The other five patients withnormal sequences presented several features not manifested by the three patients with the mutations. No mutation was found in the 5' flanking region of any patients or their parents.
CONCLUSIONS—A novel initiation codon mutation wasfound in a Japanese patient with HPD/DRD. The clinical manifestationscommon to the patients with HPD/DRD with a mutated GTP-CH-I gene werealso identified. Although focal manifestations of HPD/DRD associatedwith the mutations of this gene will be broadened, it is inferred thatthese clinical features are fundamental to HPD/DRD caused by mutationsin this gene.
相似文献
METHODS—The exons, exon-intron junctions, and anindispensable part of the 5' flanking region of the GTP-CH-I gene weresequenced in the eight clinically diagnosed patients with HPD/DRD andtheir asymptomatic parents.
RESULTS—Three independent mutations in theGTP-CH-I gene were found in three patients. One of the patients and herasymptomatic mother were heterozygous for a novel mutation at theinitiation codon. The three patients with dissimilar GTP-CH-I mutationsexhibited similar clinical features. The other five patients withnormal sequences presented several features not manifested by the three patients with the mutations. No mutation was found in the 5' flanking region of any patients or their parents.
CONCLUSIONS—A novel initiation codon mutation wasfound in a Japanese patient with HPD/DRD. The clinical manifestationscommon to the patients with HPD/DRD with a mutated GTP-CH-I gene werealso identified. Although focal manifestations of HPD/DRD associatedwith the mutations of this gene will be broadened, it is inferred thatthese clinical features are fundamental to HPD/DRD caused by mutationsin this gene.
相似文献