全文获取类型
收费全文 | 4268篇 |
免费 | 229篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 82篇 |
儿科学 | 90篇 |
妇产科学 | 45篇 |
基础医学 | 511篇 |
口腔科学 | 57篇 |
临床医学 | 281篇 |
内科学 | 1081篇 |
皮肤病学 | 36篇 |
神经病学 | 244篇 |
特种医学 | 275篇 |
外科学 | 783篇 |
综合类 | 23篇 |
预防医学 | 180篇 |
眼科学 | 88篇 |
药学 | 268篇 |
中国医学 | 9篇 |
肿瘤学 | 457篇 |
出版年
2023年 | 14篇 |
2022年 | 42篇 |
2021年 | 83篇 |
2020年 | 30篇 |
2019年 | 57篇 |
2018年 | 68篇 |
2017年 | 65篇 |
2016年 | 63篇 |
2015年 | 73篇 |
2014年 | 114篇 |
2013年 | 133篇 |
2012年 | 199篇 |
2011年 | 193篇 |
2010年 | 129篇 |
2009年 | 115篇 |
2008年 | 191篇 |
2007年 | 210篇 |
2006年 | 172篇 |
2005年 | 206篇 |
2004年 | 153篇 |
2003年 | 159篇 |
2002年 | 191篇 |
2001年 | 189篇 |
2000年 | 187篇 |
1999年 | 152篇 |
1998年 | 46篇 |
1997年 | 64篇 |
1996年 | 39篇 |
1995年 | 31篇 |
1994年 | 33篇 |
1993年 | 25篇 |
1992年 | 118篇 |
1991年 | 102篇 |
1990年 | 99篇 |
1989年 | 111篇 |
1988年 | 107篇 |
1987年 | 82篇 |
1986年 | 72篇 |
1985年 | 76篇 |
1984年 | 53篇 |
1983年 | 48篇 |
1982年 | 19篇 |
1981年 | 14篇 |
1979年 | 31篇 |
1978年 | 10篇 |
1977年 | 11篇 |
1976年 | 11篇 |
1975年 | 19篇 |
1973年 | 13篇 |
1968年 | 13篇 |
排序方式: 共有4510条查询结果,搜索用时 15 毫秒
21.
22.
T Sakata 《Scandinavian journal of gastroenterology》1988,23(10):1200-1202
Influence of hindgut bypass on the epithelial cell production rates of the small and large intestine was tested in rats. Hindgut bypass decreased cryptal cell production rates of the jejunum, ileum, cecum, and distal colon by 40-65%. These results suggest that the entrance of ileal effluent into the hindgut and, presumably, the resultant microbial production of short-chain fatty acids are required to maintain the normal epithelial cell proliferation not only in the hindgut but also in the small intestine. 相似文献
23.
H Ohta K Yumara-Yagi N Sakata M Inoue K Kawa-Ha 《Acta paediatrica (Oslo, Norway : 1992)》1994,83(10):1113-1114
24.
The number, size, and location of cerebral infarctions, and blood flow in the middle cerebral artery as seen on proton magnetic resonance imaging were assessed in six white adults with angiographically documented moyamoya. Findings were correlated with clinical presentation, computed tomography, and angiography. Large hemispheric infarctions were found in five hemispheres, predominantly in watershed regions. Subcortical infarctions (n = 56) were found in all hemispheres. They were predominantly located in the centrum semiovale, in the distal beds of supply of the penetrating branches of the anterior and middle cerebral arteries. Infarction of the putamen was found in three hemispheres, caudate nucleus in four, globus pallidus in two, and anterior limb of the internal capsule in two. There were none in the posterior limb of the internal capsule, thalamus, brain stem, or cerebellum. Middle cerebral artery flow was visualized as a signal-void flow sign in only three hemispheres. Cerebral infarctions due to moyamoya are bilateral, multiple, often small, and asymptomatic, affecting predominantly the carotid circulation in watershed regions. Subcortical infarctions in the centrum semiovale and large hemispheric infarctions in hemodynamically compromised areas are the predominant findings. 相似文献
25.
K Fujimoto T Sakata H Etou K Fukagawa K Ookuma K Terada K Kurata 《The American journal of the medical sciences》1992,303(3):145-150
To maintain reduced body weight by behavioral therapy in moderately obese patients, body weight was measured four times daily and charted in a weekly graph. Seventy-two female patients with simple obesity were divided into two groups: 55 patients with appliance of charting of weight pattern (group-I), and 17 patients without the charting (group-II). The percentage of patients followed for 2 years was different between group-I (87%) and group-II (65%) during 2 years after completion of weight reduction therapy interviews (p less than 0.05). Forty-eight of group-I patients succeeded in decreasing their weight by 15.2 +/- 1.5 (mean +/- SEM) kg during the 6.5 +/- 0.8 months of the therapy interviews. They were followed up for 3.8 years with no rebound weight gain. Eleven patients in group-II also succeeded in decreasing their weight by 16.8 +/- 1.9 kg during 7.8 +/- 1.3 months but their body weight rebounded by 9.0 kg during the 2-year followup period. Twelve of 15 male patients with weight charting maintained reduced weight during 4.3 years. It was easier and more effective for obese patients to maintain weight graphs for the longer period than to record no weight graphs. Obese patients could themselves monitor irregular weight patterns produced by overeating and correct the irregularities in food intake and daily lifestyles. This seems to explain why the illustration of daily fluctuations of weight measurements was useful for long-term maintenance of weight reduction. 相似文献
26.
27.
Experience with high-dose gadolinium MR imaging in the evaluation of brain metastases. 总被引:6,自引:0,他引:6
W T Yuh J D Engelken M G Muhonen N A Mayr D J Fisher J C Ehrhardt 《AJNR. American journal of neuroradiology》1992,13(1):335-345
PURPOSE: To assess the effectiveness and safety of higher doses of gadoteridol in the MR evaluation of patients with brain metastases. MATERIALS AND METHODS: Thirty-one patients with a clinical suspicion of brain metastases were studied prospectively with gadoteridol, a new, nonionic, low-osmolality contrast agent. Each patient received an initial injection of 0.1 mmol/kg and an additional dose of 0.2 mmol/kg 30 minutes later. Images were obtained before, immediately after, and 10 and 20 minutes after the initial dose. Images also were acquired immediately after the additional dose of gadoteridol. RESULTS: No adverse effects were attributed to the injection of gadoteridol. Four patients' examinations were excluded from analysis because of machine malfunction (two patients) and excessive motion artifact (two patients). Four patients had no detectable metastases. After the additional dose of gadoteridol, there was a marked qualitative improvement in lesion conspicuity and detection. The conspicuity of 80 of 81 lesions was increased in the high-dose studies, and 46 new lesions were detected in 19 of 27 patients. Quantitative image analysis demonstrated a significant increase in normalized mean lesion contrast between the initial-dose and high-dose studies (35 lesions identified in 13 patients, P less than .0001). The additional information gained by high-dose examinations contributed to a potential modification of the treatment in 10 of 27 patients. High-dose examinations increased flow-related artifact in the posterior fossa in 12 of 27 patients. CONCLUSION: Based on our preliminary results, high-dose gadolinium-enhanced MR examinations may have advantages over 0.1 mmol/kg examinations in detecting early and/or small metastases. This may be significant in the management of patients with cerebral metastases. 相似文献
28.
The major concern of the national population policy in Taiwan in recent years has been to lower the incidence of hereditary diseases and mental retardation in the general population. It has been estimated that there are around 10,000 mentally retarded school children in Taiwan. If effective chromosomal screening can be extended to these children, some of the family members who are carriers of balanced chromosomal rearrangements may benefit from follow-up studies and genetic counseling. The present report is the result of a pilot study conducted from 1988 to 1991 to explore the possibility of chromosomal screening of mentally retarded school children in Taipei. A total of 871 blood samples were collected from 1,147 children registered in 46 schools or residing in homes for the retarded. Chromosomal analysis was successfully accomplished on 674 out of 871 blood samples. The following chromosomal abnormalities were observed: 28 Down's syndrome, four Klinefelter syndrome, one XYY, one triple X, 11 translocations, seven inversions, four mosaics, three duplications, one deletion and one with an extra marker chromosome. After follow-up cytogenetic analyses of 13 families with probands with structural chromosomal anomalies, three of these families were shown to have one or two carriers of balanced translocated chromosomes. It seems that the present screening system would not be practical or cost-effective if it were applied island-wide in the future. 相似文献
29.
To clarify the morphological changes in renal proximal tubules at the onset of diabetic nephropathy, we observed 177 biopsy samples from patients with Non-Insulin-Dependent Diabetics (NIDDM) using light and electron microscopy. Group I had no proteinuria (p.u.), group II had p.u. < or = 0.5 g/day, group III had p.u. > 0.5 g/day, group IV had serum creatine level (Cr) > 1.5 mg/dl. Twenty age-matched normal patients and 80 patients with IgA nephropathy were used as controls. In groups I and II, the following features were significantly different from those in the controls: spherical enlargement of mitochondria (MT) in proximal tubule cells, hypertrophy of proximal tubule cells and their nuclei, and thickening of both the proximal tubule basement membrane (TBM) and the glomerular basement membrane (GBM). Among the histological changes observed in group I, the thickness of the GBM and TBM indicated that the disease would lead to diabetic nephropathy. MT enlargement was positively correlated with nuclear and cytoplasmic enlargement of the proximal tubule cells in diabetic patients (p < 0.05), but was not correlated with other morphological changes or disease prognosis. Glomerular nodular lesions, glomerular sclerotic change, and cortical tubulointerstitial fibrosis became evident in groups III and IV. From the above, we concluded that MT enlargement and thickening of the TBM are possible causes of reduced active transport in the proximal tubules, causing microalbuminuria in diabetics, and initial impairment of post-tubule transport. 相似文献
30.
Kaoru Hatanaka Xiang-An Li Ling Guo Toshiyuki Sakata Judith A. Gillissen Akira Yoshioka Akira Yamamoto 《Thrombosis research》1994,74(6):643-654
We have experienced a coagulation factor VIII-deficient patient whose plasma has normal protein S (PS) activity and masses of free PS and its bound form in complex with C4b-binding protein (C4BP). Although the patient's plasma showed a normal ratio of free PS to PS-C4BP complex in the presence of 5 mM EDTA, the plasma gave an abnormally retarding major C4BP peak together with a major PS peak in the crossed immunoelectrophoresis (CIE) in the presence of 2 mM CaCl2. It was revealed that the major peak was formed by a mixture of PS-C4BP complex and free form. The addition of normal human plasma (NHP) to the patient's plasma inhibited the retardation of the major PS-C4BP complex. These suggest that the patient's plasma lacks some component(s) to inhibit Ca2+-dependent association of PS with C4BP. 相似文献