全文获取类型
收费全文 | 5728篇 |
免费 | 306篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 38篇 |
儿科学 | 84篇 |
妇产科学 | 95篇 |
基础医学 | 750篇 |
口腔科学 | 165篇 |
临床医学 | 351篇 |
内科学 | 1487篇 |
皮肤病学 | 104篇 |
神经病学 | 498篇 |
特种医学 | 286篇 |
外科学 | 902篇 |
综合类 | 41篇 |
一般理论 | 1篇 |
预防医学 | 165篇 |
眼科学 | 79篇 |
药学 | 332篇 |
中国医学 | 9篇 |
肿瘤学 | 671篇 |
出版年
2023年 | 32篇 |
2022年 | 79篇 |
2021年 | 130篇 |
2020年 | 60篇 |
2019年 | 94篇 |
2018年 | 124篇 |
2017年 | 68篇 |
2016年 | 108篇 |
2015年 | 90篇 |
2014年 | 132篇 |
2013年 | 149篇 |
2012年 | 251篇 |
2011年 | 269篇 |
2010年 | 151篇 |
2009年 | 107篇 |
2008年 | 208篇 |
2007年 | 224篇 |
2006年 | 240篇 |
2005年 | 267篇 |
2004年 | 269篇 |
2003年 | 288篇 |
2002年 | 304篇 |
2001年 | 248篇 |
2000年 | 217篇 |
1999年 | 209篇 |
1998年 | 98篇 |
1997年 | 68篇 |
1996年 | 61篇 |
1995年 | 64篇 |
1994年 | 53篇 |
1993年 | 47篇 |
1992年 | 123篇 |
1991年 | 132篇 |
1990年 | 115篇 |
1989年 | 121篇 |
1988年 | 117篇 |
1987年 | 101篇 |
1986年 | 90篇 |
1985年 | 71篇 |
1984年 | 60篇 |
1983年 | 50篇 |
1982年 | 36篇 |
1981年 | 31篇 |
1980年 | 22篇 |
1979年 | 31篇 |
1978年 | 32篇 |
1976年 | 22篇 |
1975年 | 23篇 |
1969年 | 20篇 |
1968年 | 25篇 |
排序方式: 共有6058条查询结果,搜索用时 11 毫秒
61.
62.
A total of 573 cases of endometrial adenocarcinomas, composed of patients that had been hysterectomized from 1949 to 1985 at the Cancer Institute Hospital in Tokyo, have been clinicopathologically investigated to evaluate the degree of the myometrial invasion, meaning the "Depth" as a postoperative prognostic factor of this type of cancer. These patients were classified into groups, depending on the depth of the invasion. The Depth d group, showing a myometrial invasional depth of over two-thirds of the uterine wall, revealed a rate of 61.3% of the lymph node metastasis positive cases, and accounted for 50.0% of the postoperative survivals. These values were statistically worse, when compared to those of the Depth a to c groups, which showed less invasional depth. Thus it was concluded that "Depth" is an important prognostic factor in cases of an endometrial adenocarcinoma. 相似文献
63.
Jun Yoshida Masaaki Mizuno Itaru Inoue Toshihiko Wakabayasi Kenichiro Sugita Hisao Seo Kazumi Chiba 《Journal of neuro-oncology》1990,8(3):221-229
Summary Monoclonal antibody (MCA) G-22 is directed against a human glioma-associated surface antigen. Its availability for the radioimmunodetection of human glioma was analyzed by utilizing the xenografts in athymic mice. Nude mice with subcutaneous grafts of U251-MG or U251-SP glioma received intravenous administration of 123I or 131I labeled F(ab)2 fragment or whole immunoglobulin. Results of radioimaging revealed that 123I-labeled antibody was better than the 131I-labeled. It was also noted that administration of 123I-labeled F(ab)2 fragment of G-22 MCA enabled the imaging of human glioma xenografts weighing 80–650 mg after 48 hours. When biodistribution of 123I MCA was compared between G-22 and control antibodies, the percentages of dose/g in tumors were 5.228–1.799 at 30 hours and 4.112–1.132 at 48 hours with G-22 and they were 4.164–1.248 and 0.314–0.142 with control. The tumor/blood ratio until 72 hours after injection was constantly above 1 with G-22 and less than 1 with control antibody. These results indicate the potential usefulness of G-22 MCA for the radioimmunodetection of human gliomas. 相似文献
64.
We investigated the interactions in the KOC-2s human ovarian cancer cells on the effect of glucocorticoids, and sex steroid hormones in ovarian carcinomas. At 10(-8) M to 10(-5) M, dexamethasone (Dex) decreased the number of cells by 75-80% (p<0.001). At 10(-8) M and 10(-7) M, hydrocortisone (HC) decreased the number by 50% (p<0.01); at 10(-6) M and 10(-5) M, the decrease in number of cells was 65%. The E-2 decrease in number was not statistically significant. Progesterone (PG) showed at 10(-8) to 10(-6) M an increase in number of cells, however, at 10(-5) M it was decreased by 70% with a significant difference (p<0.001). Dex (10(-8)-10(-5) M), HC (10(-8)-10(-5) M) and PG (10(-5) M) produced internucleosomal cleavage of DNA into fragments with multiples of 180 to 200 bp. The TNF-alpha with addition of Dex (10(-8)-10(-5) M) and HC (10(-8)-10(-5) M) was increased after 24 h, 48 h (p<0.001); however, gradually decrease after 72 h. When PG (10(-8)-10(-5) M) was added, PG (10(-5) M) increased the secretion of TNF-alpha after 72 h. Our findings demonstrate that glucocorticoids, and PG directly induce apoptotic DNA fragmentation of KOC-2s cells. However, the secretion of TNF-alpha and expression of Fas antigen were totally different in these substances. These data provide a basis for future studies on the mechanisms of apoptotic effect of glucocorticoids, and PG and the therapeutic effects of these substances. 相似文献
65.
In order to elucidate the cause of body weight loss in the early stage of tumor progression, morphological changes of striated muscle were investigated in rabbits every 10 days after VX2 carcinoma implantation. The lean body mass started to decrease in the tumor-bearing rabbits 10 days after implantation, and body fat ratio showed a significant decrease from 30 days, different from the starved rabbits, whose lean body mass and body fat ratio started to decrease from 10 days. Morphological hallmarks of apoptosis in muscle cells were detected in tumor-bearing animals prior to the tumor growth but not in starved animals. These findings suggest that muscle cell apoptosis may be responsible for the body weight loss in the early tumor-bearing. 相似文献
66.
Shigematsu Y Korogi Y Hirai T Okuda T Sugahara T Liang L Takahashi M 《Journal of magnetic resonance imaging : JMRI》1999,10(6):939-944
This work investigated whether turbo magnetic resonance angiography (MRA) can replace conventional MRA in screening examination of intracranial arteries. A phantom was used to evaluate the effect of the zero-filling interpolation (ZFI) technique on spatial resolution and partial volume effect. Thirty-one consecutive patients underwent both turbo MRA with a slice thickness of 0.7 mm (data were measured as 1.33 mm sections) and conventional MRA with 1.0 mm sections. In the phantom studies, ZFI did not improve the spatial resolution, but the partial volume effect was somewhat reduced. In the clinical evaluation, turbo MRA showed better signal-to-noise and contrast-to-noise ratios of the intracranial major vessels than conventional MRA. The lesions included cerebral aneurysms less than 3 mm in diameter, occlusive vascular disease, arteriovenous malformations, and arteriovenous fistulas. These were all depicted on both turbo MRA and conventional MRA. Turbo MRA is a useful screening procedure because of its capability of delineating lesions in approximately half the usual imaging time. J. Magn. Reson. Imaging 1999;10:939-944. 相似文献
67.
Finger bougie method compared with pyloroplasty in the gastric replacement of the esophagus 总被引:2,自引:0,他引:2
Yamashita Y Hirai T Mukaida H Yoshimoto A Kuwahara M Inoue H Toge T 《Surgery today》1999,29(2):107-110
To elucidate the necessity of pyloroplasty for the gastric tube through the posterior mediastinum in esophageal surgery, gastric
emptying and duodenogastric reflux (DGR) were evaluated in 16 cases undergoing an anterior pylorectomy (group P) and in 16
cases treated by the finger bougie method (group F). First, the obstruction and reflux symptoms were examined based on a patient
questionnaire using a brief scoring system. The median value of the symptom score showed the patients in P to have more symptoms
than those in F; however, the difference was not significant (8.0 vs 6.0). Secondly, the swallowed Tc O4
− (85 MBq) was counted using a gamma camera at three sites on the sternal bone in the upright position based on a gastric transit
scintigram. Both the descending time of the RI peak and the clearance rates were similar between the two groups. Thirdly,
intragastric 24-h pH monitoring was carried out. Antimony pH sensors were anchored 5 and 15 cm below the esophagogastrostomy.
We could not find any difference between the two groups in both the % time pH>4 and %time pH>7. These findings thus revealed
no big difference between groups P and F. The finger bougie method to drain the vagotomized posterior mediastinal stomach
was found to achieve results similar to conventional pyloroplasty, while it was also simpler and safer. 相似文献
68.
A 45-year-old male was admitted to our hospital for investigation of a nodular shadow in segment 5 of the right lung on a
chest computed tomogram. A right middle lobectomy with mediastinal lymph node dissection was performed under a diagnosis of
lung cancer, and histologic examination confirmed small cell carcinoma. There were sarcoid reactions in the resected lymph
nodes and the lung parenchyma, but no signs of systemic sarcoidosis were evident. Sarcoid reactions are rarely observed in
the regional lymph nodes draining malignant tumors. Moreover, while they are most common in squamous cell carcinoma of the
lung, they extremely rare in small cell carcinoma. To our knowledge, this is only the third report of this unusual entity
in the English and Japanese literature. 相似文献
69.
A recent report has demonstrated that inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ release plays a crucial role in neurite growth. Here, using 31P-NMR, we examine whether activation of the metabotropic glutamate receptor 1 (mGluR1), which induces the production of IP3, could modulate phospholipid metabolism in human embryonic kidney 293 cells. mGluR1alpha- but not ionotropic glutamate receptor 1-expressing cells stimulated with glutamate exhibited a drastic reduction in the phosphorylcholine level, with corresponding increases in the level of phosphatidylcholine, a major phospholipid component. Quantitative analysis of cell growth revealed that mGluR1alpha-expressing cells cultured with 100microM glutamate were statistically significantly longer than the nontransfected cells. The effect was no longer observed following coincubation with a metabotropic glutamate receptor antagonist, (RS)-alpha-methyl-4-carboxyphenylglycine. These results suggest that mGluR1alpha activation triggers phosphatidylcholine biosynthesis and may contribute to neurite extension. 相似文献
70.
Comparison of low attenuation areas on computed tomographic scans between inner and outer segments of the lung in patients with chronic obstructive pulmonary disease: incidence and contribution to lung function 总被引:5,自引:1,他引:4 下载免费PDF全文
BACKGROUND: The low attenuation areas on computed tomographic (CT) scans have been reported to represent emphysematous changes of the lung. However, the regional distribution of emphysema between the inner and outer segments of the lung has not been adequately studied. In this study the regional distribution of low attenuation areas has been compared by quantitative CT analysis and the contribution of the regional distribution to pulmonary function tests evaluated in patients with chronic obstructive pulmonary disease (COPD). METHODS: Chest CT images and the results of pulmonary function tests were obtained from 73 patients with COPD. The lung images were divided into inner and outer segments in the upper (cranial), middle, and lower (caudal) sections. The percentage ratio of low attenuation area to corresponding lung area (LAA%) was then calculated. The LAA% of each segment was also compared with the results of pulmonary function tests. RESULTS: The mean (SD) LAA% of the inner segment was 39.1 (18.5) compared with 28.1 (13.2) for the outer segment (p<0.0001). Linear and multiple regression analyses revealed that airflow limitation is closely correlated with the inner segment LAA% of the lower lung. In contrast, the carbon monoxide transfer factor is closely correlated with the inner segment LAA% of the upper lung. CONCLUSION: Low attenuation areas on CT scans are more often found in the inner segment of the lung than in the outer segment, and the contribution of the inner segment to pulmonary function tests may be greater than the outer segment. 相似文献