首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   18438篇
  免费   912篇
  国内免费   97篇
耳鼻咽喉   317篇
儿科学   539篇
妇产科学   282篇
基础医学   2627篇
口腔科学   528篇
临床医学   1110篇
内科学   4354篇
皮肤病学   366篇
神经病学   1314篇
特种医学   712篇
外科学   3197篇
综合类   74篇
一般理论   1篇
预防医学   369篇
眼科学   242篇
药学   1202篇
中国医学   65篇
肿瘤学   2148篇
  2023年   81篇
  2022年   166篇
  2021年   397篇
  2020年   201篇
  2019年   273篇
  2018年   364篇
  2017年   298篇
  2016年   372篇
  2015年   372篇
  2014年   492篇
  2013年   577篇
  2012年   891篇
  2011年   1022篇
  2010年   578篇
  2009年   473篇
  2008年   805篇
  2007年   925篇
  2006年   931篇
  2005年   981篇
  2004年   1000篇
  2003年   948篇
  2002年   1062篇
  2001年   533篇
  2000年   499篇
  1999年   453篇
  1998年   272篇
  1997年   232篇
  1996年   211篇
  1995年   174篇
  1994年   178篇
  1993年   166篇
  1992年   397篇
  1991年   344篇
  1990年   299篇
  1989年   316篇
  1988年   266篇
  1987年   230篇
  1986年   212篇
  1985年   230篇
  1984年   188篇
  1983年   116篇
  1982年   63篇
  1981年   53篇
  1980年   53篇
  1979年   79篇
  1978年   59篇
  1977年   59篇
  1974年   57篇
  1973年   60篇
  1969年   52篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
Kimura's disease is a rare disorder that involves regional lymph nodes and the major salivary glands, which become infiltrated by eosinophils and lymphocytes. Renal lesions associated with Kimura's disease are rare. We describe the case of a 60-year-old Japanese woman who first noted a nodular mass in a salivary gland. As the nodule grew, nephrotic syndrome and heart failure developed. A biopsy of the nodule revealed Kimura's disease, and surgical excision was performed. After the operation, the heart failure and nephrotic syndrome, which were diagnosed as minimal change disease on renal biopsy, improved rapidly without steroid therapy. Four months later, the nephrotic syndrome recurred without recurrence of Kimura's disease. The patient showed marked improvement during prednisolone therapy (40 mg/d) and was in complete remission 4 weeks after the initiation of steroid therapy. This case shows that surgical excision and prednisolone therapy are useful for nephrotic syndrome associated with Kimura's disease.  相似文献   
52.
We investigated the effects of vinconate, a novel vinca alkaloid, on spatial learning deficits induced by the basal forebrain (BF) lesion in rats. Bilateral BF lesions were produced by injecting ibotenic acid (6 micrograms/0.5 microliter/side). In BF-lesioned rats, impairment of spatial learning in escaping onto the platform during training and decrease in spatial bias during the spatial probe trial in Morris's water maze task were both observed. Vinconate (5 and 10 mg/kg) treatment shortened the increase of escape latency to the platform in BF-lesioned rats and significantly reversed the decrease in spatial bias induced by the BF lesion. Vinconate (10 mg/kg) attenuated the decrease in choline acetyltransferase activity in the frontoparietal cortex caused by the BF lesion. The present study suggests that vinconate has an antiamnesic effect on the BF-lesion-induced amnesia by ameliorating the dysfunction in cholinergic neurons.  相似文献   
53.
PURPOSE: The association of BRCA2 polymorphisms at codon 372 [Asn (N)/His (H)]and codon 784 [Met (M)/Val (V)] with breast cancer risk was evaluated in Japanese women. In addition, the prognostic significance of these polymorphisms was studied in breast cancer patients. EXPERIMENTAL DESIGN: A case-control study was conducted to examine the association of the BRCA2 N/H372 polymorphism and M/V 784 polymorphism with breast cancer risk (cases = 149, controls = 154). The prognostic significance of these polymorphisms was evaluated in 139 patients with primary breast cancer. RESULTS: No significant association was observed between the N/H372 polymorphism and breast cancer risk. In contrast, a significant increase in breast cancer risk (odds ratio, 2.03; 95% confidence interval, 1.07-3.87) was observed in carriers of the variant allele (V784) of the M/V784 polymorphism as compared with noncarriers after adjustment for the classical risk factors, age, family history, parity, body mass index, and so forth. Among breast cancer patients, various clinicopathological parameters including menopausal status, tumor size, lymph node status, histological grade, and estrogen-receptor status were not significantly different between the carriers and noncarriers of the variant allele with regard to both N/H372 and M/V784 polymorphisms. The N/H 372 polymorphism was not significantly associated with patient prognosis. On the other hand, breast cancer patients carrying the variant allele of M/V784 polymorphism showed a significantly (P = 0.014) lower 3-year disease-free survival rate (63%) than noncarriers (92%). Multivariate analysis has revealed that the M/V784 polymorphism is a significant prognostic factor, being independent of the other conventional prognostic factors such as lymph node status and estrogen receptor status. CONCLUSION: These results suggest that the M/V784 polymorphism, but not the N/H372 polymorphism, would be useful in the selection of women at high risk for developing breast cancer and would also serve as a clinically useful prognostic factor in breast cancer patients.  相似文献   
54.
Screening methods for diabetes mellitus, based on fasting glucose (FPG), HbA1C and fructosamine (FRA) levels were compared with regard to their screening power. The subjects studied were 699 health examinees. A significant elevation of the mean level of each screening index was observed in diabetic subjects, but not in borderline cases compared with that of normal subjects. The FPG, HbA1C and FRA levels in diabetic subjects distributed over a wide range overlapping largely with the distributions of non-diabetic subjects. No appreciable difference in the screening power was observed between FPG and HbA1C but specificity was low in FRG for the comparable sensitivity level. In the screening methods based on the combination of two or more indices, elevation of the sensitivity was noted, but the specificity declined, resulting in an increase of re-examination rate. Among them, the combination of FPG and HbA1C indicated the highest sensitivity.  相似文献   
55.
56.
Conventional radiography was performed at diagnosis and at follow-up 5 to 9 months later in 70 children with transient synovitis of the hip. Twenty-four of the patients also had CT examination at diagnosis. The cartilaginous and osseous reaction in the conventional antero-posterior radiographs was studied as was the relation between the radiographic and CT findings concerning fat planes, joint effusion, and position of the hip joint. At diagnosis there was significant increase in the medial joint space and at follow-up examination there was significant increase in medial and cranial joint space, metaphyseal width and acetabular roof width. There was a correlation of a bulging lateral 'capsular fat plane' to the position of abduction in the affected hip which explains the asymmetry in the lateral fat plane observed in these patients.  相似文献   
57.
The usefulness of carcinoembryonic antigen (CEA) as an indicator for recurrence and a guide to the treatment was evaluated from a retrospective analysis of 88 patients with recurrent gastric cancer. Sixty-two of these patients (70.5 per cent), 25 of whom had a preoperative positive assay, and 37 a negative assay, had elevated levels of CEA after disease progression. Averaged CEA level in patients with liver metastasis was significantly higher (872 ng/ml) than in those with peritoneal metastasis (68 ng/ml), with lymph node metastasis (103 ng/ml) or with local metastasis (93 ng/ml) (p<0.01). An elevation of CEA was found prior to the clinical manifestation of recurrence, and the average lead time was 4 months. In 25 patients with a lead time of more than 4 months, survival time after CEA elevation was 13.3 months, which was longer than the 6.5 months of 28 patients with less than 4 months. Thirty-seven of the 88 patients were treated after recurrence. The average survival period after the detection of recurrence was 9.4 months in patients with surgical treatments followed by chemotherapy, 5.9 months in those with chemotherapy alone and 3.8 months in those with surgery alone. The average survival period of 26 patients with positive CEA assays in recurrence was 5.1 months longer than of patients with negative assays. This fact suggested that early detection of recurrence followed by various treatments, in the elevated CEA group, contributes to favorable results.  相似文献   
58.
Thoracic outlet syndrome is a disorder caused by neurovascular compression of the brachial nerve plexus and the subclavian artery or vein by bones and muscles. We report the MR angiographic findings of a patient with thoracic outlet syndrome.  相似文献   
59.
As a model system for mucocutaneous lymph node syndrome (MCLS), we have advocated and used mice which had been rendered tolerant to Streptococcus pyogenes-associated antigens by neonatal infection with group A fteta-hemolytic streptococci, because these mice have shown a variety of peculiar bioimmunological characteristics bearing a striking resemblance to those of MCLS patients. The results of our current investigations reaffirmed the reliability of the animal model by indicating that mice subjected to neonatal infection with 5. pyogenes , or inoculation with streptococcal pyrogenic exotoxin (SPE) in Freund's adjuvant, were perfect counterparts of patients with MCLS on account of their platelet activation and hyperaggregability in response to provocative treatment, which are familiar findings in this disease.  相似文献   
60.
In order to investigate the influence of respiratory frequency in the measurement of specific airway conductance (sGaw) during non-panting breathing, we examined specific airway conductance using a body plethysmograph (BX-82, Minato) in 20 stable pulmonary emphysema patients and 19 normal control subjects. Our body plethysmograph device can measure sGaw automatically without panting by making various corrections using a 16-bit microcomputer. We measured sGaw first at a flow of 0.5 L/sec during both inspiratory and expiratory ventilatory phases, then the respiratory frequency was changed from 0.5 to 1.0, 1.5 and 2.0 Hz. In normal control subjects sGaw, tidal volume and mouth flow significantly changed by increasing respiratory frequency, and there was a significant correlation between sGaw and mouth flow. In pulmonary emphysema patients, tidal volume decreased significantly by increasing respiratory frequency, and there was a significant correlation between sGaw and tidal volume, but sGaw and mouth flow did not change significantly by increasing respiratory frequency. These results suggest that specific airway conductance is influenced by respiratory frequency, possibly due to the change in tidal volume and mouth flow. It is necessary to standardize respiratory frequencies and mouth flows in the measurement of specific airway conductance during non-panting breathing.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号