全文获取类型
收费全文 | 10459篇 |
免费 | 473篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 111篇 |
儿科学 | 282篇 |
妇产科学 | 81篇 |
基础医学 | 1228篇 |
口腔科学 | 370篇 |
临床医学 | 602篇 |
内科学 | 2764篇 |
皮肤病学 | 147篇 |
神经病学 | 768篇 |
特种医学 | 400篇 |
外科学 | 1809篇 |
综合类 | 62篇 |
预防医学 | 357篇 |
眼科学 | 305篇 |
药学 | 687篇 |
中国医学 | 25篇 |
肿瘤学 | 976篇 |
出版年
2023年 | 55篇 |
2022年 | 91篇 |
2021年 | 194篇 |
2020年 | 110篇 |
2019年 | 121篇 |
2018年 | 160篇 |
2017年 | 141篇 |
2016年 | 156篇 |
2015年 | 171篇 |
2014年 | 224篇 |
2013年 | 307篇 |
2012年 | 422篇 |
2011年 | 493篇 |
2010年 | 289篇 |
2009年 | 234篇 |
2008年 | 455篇 |
2007年 | 488篇 |
2006年 | 504篇 |
2005年 | 463篇 |
2004年 | 452篇 |
2003年 | 479篇 |
2002年 | 460篇 |
2001年 | 384篇 |
2000年 | 371篇 |
1999年 | 379篇 |
1998年 | 133篇 |
1997年 | 93篇 |
1996年 | 93篇 |
1995年 | 86篇 |
1994年 | 61篇 |
1993年 | 69篇 |
1992年 | 267篇 |
1991年 | 234篇 |
1990年 | 235篇 |
1989年 | 269篇 |
1988年 | 207篇 |
1987年 | 194篇 |
1986年 | 190篇 |
1985年 | 175篇 |
1984年 | 130篇 |
1983年 | 100篇 |
1982年 | 64篇 |
1981年 | 48篇 |
1979年 | 74篇 |
1978年 | 47篇 |
1977年 | 48篇 |
1975年 | 48篇 |
1974年 | 48篇 |
1973年 | 48篇 |
1971年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Changes in second messenger and neurotransmitter system receptor ligand binding induced by transient forebrain ischemia were studied in the gerbil hippocampus. The animals were allowed variable periods of recovery ranging from 2 h to 7 days after 5-min bilateral carotid artery occlusion. The binding of second messenger systems ([3H]inositol 1,4,5-trisphosphate ([3H]IP3)to inositol 1,4,5-triphosphate, [3H]forskolin to adenylate cyclase and [3H]phorbol 12,13-dibutylate to protein kinase C) and neurotransmitter receptor systems ([3H]PN200-110 to L-type calcium channels. [3H]N6-cyclohexyl-adenosine to adenosine A1 and [3H]quinuclidinyl benzilate to muscarinic cholinergic receptor) were assayed using quantitative autoradiography. In the CA1 subfield, 2 h after ischemia, [3H]IP3, [3H]forskolin, and [3H]quinuclidinyl benzilate binding activities significantly decreased by 25, 17 and 13%, respectively, though no morphological abnormalities were obvious. Six hours after ischemia, the [3H]phorbol 12,13-dibutylate binding activity in the stratum oriens of the CA1 subfield increased by 15%. One day after ischemia, [3H]PN200-110 binding activity in this subfield decreased by 26%, and 7 days after ischemia, [3H]phorbol 12,13-dibutylate and [3H]N6-cyclohexyl-adenosine receptor binding activities decreased in this subfield. In particular, at 7 days after ischemia, [3H]IP3 binding activity in the CA1 subfield showed a complete decline. In the CA3 subfield, [3H]PN200-110 binding activity decreased 2 days after ischemia, and [3H]IP3 and [3H]N6-cyclohexyl-adenosine binding activities decreased 7 days after ischemia. In the dentate gyrus, the structure of which remained histologically intact after ischemic insult, [3H]IP3 and [3H]forskolin binding activities decreased 7 days after ischemia. In contrast, the [3H]phorbol 12,13-dibutylate binding activity increased in the molecular layer of the dentate gyrus 7 days after ischemia. These results indicate that marked alteration of intracellular signal transduction precedes neuronal damage in the hippocampal CA1 subfield and that the histologically intact CA3 and dentate gyrus also shows modulated neuronal transmission after ischemia. 相似文献
23.
The ionic mechanisms of the effect of extracellularly ejected recombinant human tumor necrosis factor-alpha (rhTNF-alpha) on the membrane of identified neurons R9 and R10 of Aplysia kurodai was investigated with conventional voltage-clamp, micropressure ejection, and ion substitution techniques. Micropressure-ejected rhTNF caused a marked hyperpolarization in the unclamped neuron. Clamping the same neuron at it resting potential level (-60 mV) and reejecting rhTNF-alpha with the same dose produced a slow outward current [Io (TNF)] associated with a decrease in input membrane conductance. Io (TNF) was decreased by depolarization and increased by hyperpolarization. The extrapolated reversal potential of Io (TNF) was approximately +10 mV. Ion substitution and pharmacological experiments suggest that Io (TNF) in identified neurons R9 and R10 of A. kurodai is due to a decreased Na+ conductance but not due to an activation of the Na(+)-K+ pump. Our results demonstrate that the immunomodulator TNF can act directly on the nervous system as well as on the immune system. 相似文献
24.
N Arai A Hara H Kaneko M Umeda T Shirai 《Nihon Ronen Igakkai zasshi. Japanese journal of geriatrics》1991,28(5):672-677
Elderly patients (aged greater than or equal to 65 years) with non-Hodgkin's lymphoma were treated either with CHOP or COP-BLAM therapy, and the effectiveness and reverse effects of COP-BLAM therapy were compared with those of CHOP therapy. Thirty-three patients (aged greater than or equal to 65 years) with previously untreated non-Hodgkin's lymphoma were entered either on CHOP or COP-BLAM regimen between September, 1979 and February 1990. To CHOP therapy was performed in 15 patients (median age; 70 years). Eight of them had diffuse large cell type lymphoma (large), five had diffuse medium-sized cell type (medium) and two had diffuse mixed cell type (mixed). As to clinical stage, there were patients in stage II, 4 in stage III and 9 in stage IV in CHOP group. Of 18 patients (median age; 68 years), who were treated with COP-BLAM therapy, 8 had of large lymphoma and 10 medium lymphomas in histopathological classification. In terms of clinical stage, there were 5 patients in stage II, 4 in stage III and 9 in stage IV. CHOP therapy and COP-BLAM therapy were performed according to the method reported by McKelvey et al, and by Laurence et al., respectively, using the full doses of drugs without consideration the age. Complete remission (CR) was achieved in seven (46.7%) of 15 patients treated with CHOP therapy. In this group, five (38.5%) of 13 patients in advanced stages (stage III or IV) entered CR. Of 18 patients subjected to COP-BLAM therapy, 15 (83.3%) achieved CR. Among 13 patients in advanced stage treated with COP-BLAM therapy, CR was achieved in 11 (84.6%).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
25.
Extracardiac Direct Total Cavopulmonary Connection 总被引:2,自引:0,他引:2
Masaaki Yamagishi MD Yuzuru Nakamura MD Toshiyuki Kanazawa MD Noriyasu Kawada MD 《The Annals of thoracic surgery》1997,64(6):1817-1819
We report a successful extracardiac direct total cavopulmonary connection without prosthetic materials performed in a 3-year-old boy with tricuspid atresia, infundibular pulmonary stenosis, and normally positioned great arteries. The transected pulmonary trunk was bought down posterolaterally with respect to the right atrium and was anastomosed end-to-end with the inferior vena cava. 相似文献
26.
With the recent advances in DNA sequencing technology, a succession of entire genome sequences have been published. A number of genome projects are underway in pathogenic fungi. From these, we present the history and current status of the genomic analysis of Candida albicans. The sequencing project for this organism has been undertaken at Stanford University, and is now nearing the end. 相似文献
27.
Y Tano T Matsushima Y Kobashi T Samukawa M Kimura H Hara J Tanabe 《Nihon Kyōbu Shikkan Gakkai zasshi》1992,30(5):881-885
We assessed the period of administration of antibiotics required for cases of mycoplasmal pneumonia. The subjects were 38 patients with mycoplasmal pneumonia admitted to our hospital. These patients were treated with 100 mg minocycline or 500 mg erythromycin by intravenous infusion twice a day. They were divided into a 6 day-administration group (Group A; 16 cases) and a 9 day-administration group (Group B; 17 cases). Administration was discontinued on the 4th day or earlier in 5 cases due to side effects. A comparative assessment was made between Groups A and B with respect to body temperature, WBC, erythrocyte sedimentation rate, CRP, and chest X-ray on the 3rd, 6th, and 9th days of treatment, but no significant difference was observed. Residual shadows at the end of treatment were present in 100% of Group A and in 47% of Group B, but they disappeared gradually in both groups. No cases of recurrence were observed in either Group A or B within 1 month after the completion of treatment. Regarding the treatment period for mycoplasmal pneumonia by intravenous infusion of minocycline or erythromycin, no significant clinical difference was observed between the 6 day-administration group and the 9 day-administration group, suggesting that 6 days of administration is sufficient for treatment. 相似文献
28.
A Sakamoto T Miyazaki K Komori K Taketomi K Tobinaga M Kishikawa S Kohno K Hara 《Nihon Kyōbu Shikkan Gakkai zasshi》1992,30(8):1532-1536
A 14-year-old girl was admitted because of cough, chest pain and hemosputum. Chest roentgenogram on admission showed a pneumothorax and a cavitary lesion with niveau formation in the right lung and cystic lesions in the bilateral lung fields. After bed rest and intravenous administration of antibiotics for two weeks, the right lung inflated well and the niveau formation disappeared, and the patient was discharged. One week later, she was readmitted with sudden-onset severe dyspnea, caused by bilateral pneumothoraces. Emergency tube thoracostomy and wedge resection of the bullous lesion was performed. Macroscopically, multiple small cystic changes were seen on the surface of the right lung. Histological examination revealed nodular proliferations of smooth muscle cells in the interstitium and vessel walls in the lung, which contained slit-like lymphatic channels. The diagnosis of pulmonary lymphangiomyomatosis was made. In this case, we could not measure receptors for estrogen and progesterone. Recently, hormonal therapy and oophorectomy have been reported as being useful. Tamoxifen (Norvadex) was therefore initiated, and the patient has remained well with slight dyspnea on exertion. There has been no recurrence of pneumothorax. Lymphangiomyomatosis is a rare disease of unknown etiology which occurs exclusively in women, mostly in those of reproductive age. We report a 14-year-old female patient with lymphangiomyomatosis associated with repeated pneumothorax, who had been under treatment for epilepsy. We believe this case to be of importance because of the long discussed relation between pulmonary lymphangiomyomatosis and tuberous sclerosis. 相似文献
29.
K Tozuka H Moriguchi Y Hara Y Yonese H Abe T Konjiki 《Hinyokika kiyo. Acta urologica Japonica》1986,32(8):1093-1097
A clay film was made of the stone powder and water drops on a slide glass and dried at 100 to 110 degrees C or at room temperature in the horizontal position for 20 calcium oxalate stones which had been received between April, 1978 and August 1980. Each clay film was scanned with an X-ray diffractometer using CuK alpha radiation, stored at room temperature in a wooden sample case and analysed again by X-ray five to seven years after the first X-ray analysis. Then the recent diffractograms of 20 powder samples were compared with the previous ones regarding the peak heights at 14.2 degrees, 14.8 degrees and 25.8 degrees (2 theta), which were considered representative of weddellite, whewellite and apatite contents and designated as Iwe, Iwh and Iap, respectively. Since there was a good correlation between Iwe/Iwe + Iwh + Iap and weddellite/weddellite + whewellite + apatite that was determined by thermogravimetry (Fig. 1), the transformation rate of weddellite to whewellite can be expressed as the change of Iwe/Iwe + Iwh + Iap. One sample Iwe/Iwe + Iwh + Iap of which decreased by 48% in seven years (Fig. 3) and another sample Iwe/Iwe + Iwh + Iap of which increased by 10% in five years (Table) were excluded from this study because the clay films of these samples might have been overheated or incompletely dried before the first X-ray analysis.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
30.