全文获取类型
收费全文 | 24229篇 |
免费 | 1107篇 |
国内免费 | 161篇 |
专业分类
耳鼻咽喉 | 231篇 |
儿科学 | 477篇 |
妇产科学 | 209篇 |
基础医学 | 2959篇 |
口腔科学 | 575篇 |
临床医学 | 1496篇 |
内科学 | 6281篇 |
皮肤病学 | 545篇 |
神经病学 | 2292篇 |
特种医学 | 885篇 |
外科学 | 4096篇 |
综合类 | 61篇 |
一般理论 | 4篇 |
预防医学 | 582篇 |
眼科学 | 709篇 |
药学 | 1570篇 |
中国医学 | 37篇 |
肿瘤学 | 2488篇 |
出版年
2023年 | 155篇 |
2022年 | 326篇 |
2021年 | 564篇 |
2020年 | 293篇 |
2019年 | 368篇 |
2018年 | 482篇 |
2017年 | 373篇 |
2016年 | 486篇 |
2015年 | 532篇 |
2014年 | 653篇 |
2013年 | 786篇 |
2012年 | 1418篇 |
2011年 | 1497篇 |
2010年 | 888篇 |
2009年 | 740篇 |
2008年 | 1286篇 |
2007年 | 1512篇 |
2006年 | 1401篇 |
2005年 | 1534篇 |
2004年 | 1477篇 |
2003年 | 1340篇 |
2002年 | 1393篇 |
2001年 | 505篇 |
2000年 | 439篇 |
1999年 | 514篇 |
1998年 | 374篇 |
1997年 | 285篇 |
1996年 | 284篇 |
1995年 | 245篇 |
1994年 | 215篇 |
1993年 | 215篇 |
1992年 | 284篇 |
1991年 | 265篇 |
1990年 | 241篇 |
1989年 | 243篇 |
1988年 | 205篇 |
1987年 | 189篇 |
1986年 | 204篇 |
1985年 | 169篇 |
1984年 | 117篇 |
1983年 | 112篇 |
1982年 | 67篇 |
1981年 | 66篇 |
1980年 | 47篇 |
1979年 | 90篇 |
1978年 | 77篇 |
1977年 | 66篇 |
1974年 | 44篇 |
1973年 | 47篇 |
1969年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Susumu Ishikawa M.D. Akio Ohtaki M.D. Toru Takahashi M.D. Tetsuya Koyano M.D. Yutaka Hasegawa M.D. Satoshi Ohki M.D. Yukitaka Isa M.D. Kennichi Arai M.D. Fumio Kunimoto M.D. Yasuo Morishita M.D. 《Journal of cardiac surgery》1997,12(3):176-179
A bstract The purpose of this study was to assess the efficacy of nasal mask bi-level positive airway pressure (BiPAP) support in managing respiratory failure following cardiovascular surgery. A total of 20 patients requiring postoperative prolonged respiratory support of 72 hours or longer were studied. BiPAP support was used for eight patients (BiPAP group); the other 12 patients were managed using ordinary oxygen mask treatment (control group). The mean age of the BiPAP group and control group was 65 and 58 years of age, respectively. The mean period of postoperative endotracheal intubation of the BiPAP group and control group was 12 ± 5 days and 7 ± 1 days, respectively. Reintubation was necessary in two patients of the control group. The BiPAP group patients required no reintubation. BiPAP support was discontinued within 48 hours in 6 out of 8 patients. The respiratory rates of control group increased (p < 0.1) 24 hours after extubation, however, the respiratory rates of the BiPAP group remained unchanged. The values of the respiratory index of the BiPAP group improved significantly (p < 0.01) after BiPAP management (from 1.5 ± 0.2 to 0.9 ± 0.2). The values of the control group, however, remained unchanged. A-aDO2 and Qs/Qt decreased (p < 0.1) in the BiPAP group. There were no significant differences in central venous pressure or circulatory status between the two groups. In conclusion, BiPAP support is a noninvasive management technique for postoperative respiratory failure and may also prevent prolonged endotracheal intubation. 相似文献
22.
Makoto Kamada Kenji Ohsaka Susumu Nagamine Hidemitsu Kakihata 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2003,51(10):552-556
Acute aortic dissection complicated with acute myocardial infarction (AMI) is the most fatal situation. We experienced the
successful treatment for acute type A aortic dissection complicated with inferior AMI following aortic valve replacement (AVR).
A 60-year-old man had had AVR for aortic regurgitation. Sixteen months after the AVR, he had a sudden onset of severe chest
pain with complete atrioventricular block. Immediately, temporary pacing and cardiac catheterization were conducted, showing
the occlusion of the right coronary artery due to acute type A aortic dissection. On his way to our hospital, direct current
shock was conducted 3 times for ventricular fibrillation. We replaced the ascending aorta combined with coronary artery bypass
grafting and the postoperative course was uneventful. The key to treat acute aortic dissection complicated with AMI is early
accurate diagnosis, prompt temporary pacing for bradycardia, defibrillation for lethal arrhythmia and insertion of a perfusion
catheter if possible. These preoperative hemodynamic stabilization gives us the chance to save these patients. 相似文献
23.
Age- and sex-related differences in the nerve growth factor distribution in the rat brain. 总被引:2,自引:0,他引:2
Levels of the nerve growth factor (NGF) have been measured in various brain regions of young and aged male and female rats of Wistar strain by means of a highly sensitive two-site enzyme immunoassay system for beta-NGF. Among the ten regions examined, the amount of NGF per wet weight of tissue was found to be highest in the hippocampus, irrespective of the sex and age. The NGF concentration in the hippocampus of female rats at 3 months of age was comparable to that of same aged males. Further, there was no significant difference in the NGF levels of the hippocampus between young and age males. However, the NGF level was significantly lower in aged females as compared to that in 3- or 4-month-old females, and hence the marked male-female difference was found in the NGF levels in aged Wistar rats. 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.
H Hanyu H Arai H Katsunuma R Fujita C Tomori 《Nihon Ronen Igakkai zasshi. Japanese journal of geriatrics》1991,28(2):160-165
A neuroradiological study of crossed cerebellar atrophy (CCA) was performed using X-ray CT in 103 patients suffering from unilateral supratentorial cerebrovascular diseases. CCA was demonstrated in 9 (8.7%) of 103 patients. No difference between the occurrence of CCA in cerebral hemorrhage and that in cerebral infarction was found. CCA was seen in the chronic stage of cerebrovascular disease more than 3 years since stroke occurrence, and was found to be present more frequently and to a greater extent 7 years later. No correlation between the site of bleeding and the occurrence of CCA was found. Trans-synaptic degeneration of the corticopontocerebellar tract was considered in CCA following putaminal and combined hemorrhage involving an internal capsule lesion. However, in thalamic hemorrhage, retrograde degeneration within the cerebellorubrothalamic tract was presumed. CCA following cerebral infarction was seen in patients with massive lesions in the territory of the middle cerebral artery. Multivariate analysis showed that lesions of the parietal and frontal lobes appeared to greatly contribute to the development of CCA. As the degeneration and atrophy in the thalamus on the side of the lesion appeared early and frequently, it was suggested that retrograde degeneration of the cerebellorubrothalamic tract participated, in addition to anterograde corticopontocerebellar tract degeneration, in CCA following middle cerebral artery infarction. It is likely that CCA is caused by both transsynaptic degeneration of the corticopontocerebellar tract and the cerebellorubrothalamic tract. 相似文献
26.
Makoto Watanabe Takashi Fujimoto Masayuki Iwano Hideo Shiiki Shinobu Nakamura 《Nihon Rinshō Men'eki Gakkai kaishi》2002,25(2):191-198
We describe the case of a 61-year-old woman diagnosed with primary Sj?gren's syndrome (SS) after an 8-year history of IgA nephropathy and a 3-year history of recurrent purpuric rashes. Her two daughters had previously been diagnosed with other autoimmune diseases. One daughter had Graves' disease and the other had Hashimoto's disease and systemic lupus erythematosus. The diagnosis of SS was made based on dryness of mucous membranes, Shirmer test, and parotid sialography. Thrombocytopenia, high platelet-aggregated IgG (PA-IgG) level, and normal megakaryocytes count in bone marrow suggested that her recurrent purpuric rashes were due to idiopathic thrombocytopenic purpura (ITP). Patients with SS may develop other autoimmune diseases. This case aids understanding of the immune pathogenesis and genetic background of SS. 相似文献
27.
Ishizaki K.; Yoon D. M.; Yoshida N.; Yamazaki M.; Arai K.; Fujita T. 《British journal of anaesthesia》1995,75(5):636-638
We have studied the effect of intrathecal administration of N-methyl-D-
aspartate (NMDA) receptor antagonists on the minimum alveolar anaesthetic
concentration (MAC) of isoflurane in rats. In Wistar rats fitted with
indwelling intrathecal catheters, we determined the MAC of isoflurane after
administration of a competitive NMDA receptor antagonist, APV (0.01, 0.1,
1.0, 10, 30 micrograms), a non-competitive NMDA receptor antagonist, MK801
(0.1, 1.0, 10, 30 micrograms). NMDA (0.01, 0.1, 1.0, 10, 30 micrograms) and
saline. APV at all doses except 0.01 micrograms decreased MAC by 17.1-32%
(P < 0.001 and P < 0.0001). Although MK801 at 10 and 30 micrograms
reduced MAC by 24.3-31.7% (P < 0.001 and P < 0.0001), lower doses did
not affect MAC. Intrathecal administration of NMDA reversed these decreases
in MAC, but not to control values with APV 10 and 30 micrograms and MK801
30 micrograms. We suspect that NMDA and NMDA receptor antagonists play
important roles in the spinal cord in determining the MAC of isoflurane.
相似文献
28.
Estrogenic Induction of NADPH- Diaphorase Activity in the Preoptic Neurons Containing Estrogen Receptor Immunoreactivity in the Female Rat 总被引:1,自引:0,他引:1
Nitric oxide and estrogen have been shown to play a critical role in the control of female reproductive function. In order to determine an anatomical relationship between nitric oxide generating neurons and estrogen target neurons, NADPH-diaphorase histochemistry was combined with estrogen receptor immunohistochemistry in the female medial preoptic area. While only a few weakly stained neurons for NADPH-diaphorase were found in ovariectomized control rats, a drastic increase in NADPH-diaphorase activity was observed in the medial preoptic nucleus of estradiol-treated ovariectomized animals. The total number of NADPH-diaphorase neurons in the estradiol-treated group increased three-fold relative to controls, and more than 80% of those neurons contained estrogen receptor-immunoreactivity in their nuclei. Since neuronal NADPH-diaphorase is nitric oxide synthase, the present result suggests that nitric oxide synthase activity can be positively regulated by estradiol in neurons containing estrogen receptor in the female medial preoptic nucleus. 相似文献
29.
Y Kitagawa M Ueda N Ando K Ishibiki M Kitajima Y Kabayashi T Arai 《Nihon Geka Gakkai zasshi》1992,93(9):914-917
In recent years, the most common causative organism of hospital infections has been methicillin resistant Staphylococcus aureus (MRSA). The major mechanism of beta-lactam resistance in MRSA is attributed to the production of a specific penicillin binding protein (PBP2'), which is a product of mecA gene, with extremely low binding affinities to beta-lactams. In the present study, we have established a rapid identification method of MRSA by sensitive detection of mecA gene using nested PCR. Nested PCR method amplifying the target DNA in two steps enhanced the efficiency of the second round amplification. By means of this method, mecA gene was successfully detected in clinical samples, such as blood, pus, sputum and feces within 3-4 hrs. Rapid diagnosis of MRSA-bacteremia is particularly important for prevention of sever systemic infection. There are some strains of S. aureus which possess mecA gene in spite of low minimal inhibitory concentration of DMPPC. In these strains expression of mecA gene is induced by contact of beta-lactams and they obtain methicillin resistance. Using nested PCR method, these latent MRSA are rapidly and certainly detectable. This method should be useful for early and effective detection of MRSA hospital infections. 相似文献
30.
Koichi Shimizu M.D. Hirokuni Arai M.D. Tohru Sakamoto M.D. Makoto Sunamori M.D. Akio Suzuki M.D. 《Journal of cardiac surgery》1997,12(3):198-200
A bstract A 61-year-old woman suffering from Jarcho-Levin syndrome (JLS) was associated with atrial septal defect and partial anomalous pulmonary venous return and underwent corrective surgery. Pressure controlled postoperative ventilator therapy is preferred in patients with JLS. 相似文献