全文获取类型
收费全文 | 379173篇 |
免费 | 24198篇 |
国内免费 | 2809篇 |
专业分类
耳鼻咽喉 | 5182篇 |
儿科学 | 8216篇 |
妇产科学 | 10122篇 |
基础医学 | 53109篇 |
口腔科学 | 11814篇 |
临床医学 | 30105篇 |
内科学 | 78283篇 |
皮肤病学 | 8547篇 |
神经病学 | 27209篇 |
特种医学 | 13914篇 |
外国民族医学 | 82篇 |
外科学 | 60578篇 |
综合类 | 9974篇 |
现状与发展 | 1篇 |
一般理论 | 64篇 |
预防医学 | 17444篇 |
眼科学 | 9444篇 |
药学 | 30985篇 |
1篇 | |
中国医学 | 2201篇 |
肿瘤学 | 28905篇 |
出版年
2021年 | 2623篇 |
2019年 | 2729篇 |
2018年 | 4524篇 |
2017年 | 3435篇 |
2016年 | 3523篇 |
2015年 | 4025篇 |
2014年 | 5697篇 |
2013年 | 7385篇 |
2012年 | 10041篇 |
2011年 | 10221篇 |
2010年 | 6200篇 |
2009年 | 5847篇 |
2008年 | 9455篇 |
2007年 | 10287篇 |
2006年 | 10216篇 |
2005年 | 9272篇 |
2004年 | 8776篇 |
2003年 | 8518篇 |
2002年 | 8192篇 |
2001年 | 28211篇 |
2000年 | 28772篇 |
1999年 | 23619篇 |
1998年 | 5159篇 |
1997年 | 4249篇 |
1996年 | 3828篇 |
1995年 | 3477篇 |
1994年 | 3104篇 |
1993年 | 2841篇 |
1992年 | 16049篇 |
1991年 | 14811篇 |
1990年 | 14162篇 |
1989年 | 13961篇 |
1988年 | 12580篇 |
1987年 | 12061篇 |
1986年 | 11105篇 |
1985年 | 10322篇 |
1984年 | 6914篇 |
1983年 | 5600篇 |
1982年 | 2720篇 |
1979年 | 5479篇 |
1978年 | 3348篇 |
1977年 | 2974篇 |
1975年 | 2642篇 |
1974年 | 3064篇 |
1973年 | 2867篇 |
1972年 | 2832篇 |
1971年 | 2777篇 |
1970年 | 2517篇 |
1969年 | 2547篇 |
1968年 | 2250篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
991.
N Sakai K Sawada K Koizumi T Tarumi N Sato M Ieko S Sakurama T Yasukouchi Y Matsunaga 《[Rinshō ketsueki] The Japanese journal of clinical hematology》1992,33(8):1077-1083
A 30-year-old female at 27 weeks' gestation, was hospitalized on September 24 1990 because of the premature rupture of the amniotic sac. She underwent Caesarean section on the same day with 700 ml blood loss, but no blood transfusion was required. For several days after the operation, her hemoglobin level remained 7.8 g/dl and did not increase significantly in spite of parenteral iron therapy. On the 9th postoperative day, chills and pyrexia developed with leukopenia. Bone-marrow aspiration revealed severe erythroblastopenia with giant proerythroblasts, suggesting recent HPV infection, which was confirmed by the presence of anti-HPV IgM and HPV antigen by ELISA. The hemoglobin level gradually decreased to 6.0 g/dl by the 21st day, then began to increase rapidly. The serum of acute-phase containing HPV antigens inhibited BFU-E and CFU-E but not CFU-GM. The serum of convalescent-phase inhibited neither erythroid colony growth nor myeloid colony growth. These results indicate that the inhibitory effect of HPV in colony assay is highly specific for erythropoiesis and that HPV play a role in transient cessation of erythropoiesis. The reason, however, for leukopenia in HPV infection remained unclear. This case shows that HPV infection may induce severe hematological disorders even in normal person under erythropoietic stress. 相似文献
992.
Acute thoracic aortic dissection has a high mortality if untreated, so the diagnosis must be rapidly made if mortality is to be lowered significantly. Multiple imaging techniques are often used. This retrospective study from 1988 to 1993 assesses the usefulness in diagnosis of chest X-rays, computed tomography (CT) scanning, aortography, magnetic resonance imaging (MRI), trans-thoracic (TTE) and trans-oesophageal (TOE) echocardiography. Forty-two patients with a final clinical diagnosis of dissection were studied. The diagnosis was confirmed in 16 (13 at surgery and three at autopsy). Three died with dissection given as the only cause for death. Chest X-ray abnormalities were seen in all 19 patients with surgery or death from dissection, with a widened mediastinum and/or dilated aorta being present in 17. In the group of 16 patients with surgery or autopsy proof, CT scans found dissections in 9 of 12 patients studied and correctly classified the type in only five. Aortography was performed in five, with accurate depiction of dissection and type in all. TTE found dissections in three of eight patients imaged by this method. MRI and TOE were performed each on two patients, with accurate depiction of dissection and type in each. Because of the relatively low sensitivity of CT scanning in defining aortic dissections Westmead Hospital is currently assessing the use of TOE as the prime imaging modality prior to surgical intervention. 相似文献
993.
994.
Cationic lipids enhance cellular uptake and activity of phosphorothioate antisense oligonucleotides. 总被引:37,自引:0,他引:37
C F Bennett M Y Chiang H Chan J E Shoemaker C K Mirabelli 《Molecular pharmacology》1992,41(6):1023-1033
We have investigated the use of a cationic lipid preparation to enhance antisense oligonucleotide activity in human umbilical vein endothelial cells. A liposomal preparation containing the cationic lipid N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTMA) was found to increase by at least 1000-fold the potency of an antisense oligonucleotide (ISIS 1570) that hybridizes to the AUG translation initiation codon of human intercellular adhesion molecule-1. In the presence of 8 microM DOTMA, 6-15-fold more 35S-ISIS 1570 associated with cells, at oligonucleotide concentrations from 0.01 to 5 microM, than did in the absence of DOTMA. Both 35S-ISIS 1570 association with cells and antisense activity were increased as a function of DOTMA concentration and with increasing time of incubation with the cationic lipid. Fluorescein-labeled ISIS 1570 was used to assess the intracellular distribution of the oligonucleotide in the presence and absence of DOTMA. In the absence of DOTMA, the oligonucleotide localized to discrete structures in the cytoplasm of the cell, resulting in a punctate fluorescence pattern. In the presence of DOTMA, cellular fluorescence markedly increased and the oligonucleotide localized within the nucleus, as well as to discrete structures in the cytoplasm. Accumulation of the oligonucleotide in the nucleus in the presence of DOTMA was time and temperature dependent. Nuclear accumulation was inhibited by preincubation of the cells with monensin but not chloroquine, NH4Cl, nocodazole, colcemid, or brefeldin A. These data demonstrate that cationic lipids increase antisense activity by increasing the amount of oligonucleotide associated with cells and altering intracellular distribution of the oligonucleotide. 相似文献
995.
996.
We reported clinical and neuropathological observations of a 41-year-old man with Degos disease. He first noted painless skin lesions over the upper extremities in January, 1982. Three years later he was diagnosed as Degos disease by skin biopsy, and treatment with aspirin was started. In September, 1985, he complained of paresthesia on his right arm, followed by a series of new neurological manifestations suggesting multifocal spinal cord lesions. On October 28, examination of admission showed papules with central umblication over the whole body except the head, face, palms, soles and scrotum. Neurological examination revealed no weakness, diminished right biceps reflex, exaggerated patellar reflexes and Achilles reflexes, left extensor plantar reflex, hypesthesia and hypalgesia to the level of Th8, mild left spastic gait, and retention of urine. In November, he had paraparesis, loss of vibration sense of lower extremities, hypesthesia and hypalgesia to the level of TH4, and weakness of right upper extremity. In December, he showed tetraplegia, left-sided facial palsy, and hypesthesia and hypalgesia to the level of C5. In January, 1986, he showed right facial palsy, left facial hypesthesia, pseudobulbar palsy. In February, he had bilateral abducens nerve palsy and hiccups. On February 18, he died of intracranial hemorrhages. He had episodic abdominal pain several times during admission. His condition deteriorated progressively in four months after the first manifestation of neurological symptoms, despite the therapy with heparin, urokinase, ticlopidine, dipyridamole, and prednisolone. Laboratory studies showed gradual increase of CSF proteins (from 156 mg/dl to 602 mg/dl) and extremely increased platelet aggregation.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
997.
A 54-year-old female presented with subarachnoid hemorrhage due to rupture of a small middle cerebral artery aneurysm, found to be thrombosed at surgery and not visualized on the preoperative angiograms. One major branch of the middle cerebral artery was found to be occluded near the trifurcation. The lumen of the branch proximal to the occlusion had appeared as the aneurysmal opacification on the preoperative angiograms. 相似文献
998.
999.
1000.
A Patel J W Boja J Lever R Lew R Simantov F I Carroll A H Lewin A Philip Y Gao M J Kuhar 《Brain research》1992,576(1):173-174
Because some evidence suggests that cocaine and GBR12935 bind to different sites, we utilized photoaffinity probes from both classes of compounds to see if they label the same protein. [125I]RTI-82 a cocaine analog, and [125I]DEEP, a GBR analog, labeled protein(s) showing the same molecular weight, a similar pharmacological profile and a similar sensitivity to neuraminidase. 相似文献