全文获取类型
收费全文 | 22598篇 |
免费 | 2203篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 371篇 |
儿科学 | 677篇 |
妇产科学 | 375篇 |
基础医学 | 3233篇 |
口腔科学 | 592篇 |
临床医学 | 2258篇 |
内科学 | 4127篇 |
皮肤病学 | 307篇 |
神经病学 | 1709篇 |
特种医学 | 778篇 |
外科学 | 3348篇 |
综合类 | 547篇 |
一般理论 | 26篇 |
预防医学 | 2434篇 |
眼科学 | 663篇 |
药学 | 1432篇 |
中国医学 | 17篇 |
肿瘤学 | 1949篇 |
出版年
2021年 | 296篇 |
2020年 | 171篇 |
2019年 | 258篇 |
2018年 | 339篇 |
2017年 | 265篇 |
2016年 | 301篇 |
2015年 | 332篇 |
2014年 | 478篇 |
2013年 | 721篇 |
2012年 | 1017篇 |
2011年 | 1006篇 |
2010年 | 566篇 |
2009年 | 513篇 |
2008年 | 896篇 |
2007年 | 1003篇 |
2006年 | 965篇 |
2005年 | 988篇 |
2004年 | 878篇 |
2003年 | 888篇 |
2002年 | 803篇 |
2001年 | 758篇 |
2000年 | 764篇 |
1999年 | 674篇 |
1998年 | 278篇 |
1997年 | 285篇 |
1996年 | 270篇 |
1995年 | 231篇 |
1994年 | 246篇 |
1993年 | 221篇 |
1992年 | 590篇 |
1991年 | 518篇 |
1990年 | 491篇 |
1989年 | 529篇 |
1988年 | 449篇 |
1987年 | 434篇 |
1986年 | 412篇 |
1985年 | 399篇 |
1984年 | 325篇 |
1983年 | 259篇 |
1982年 | 200篇 |
1981年 | 214篇 |
1979年 | 294篇 |
1978年 | 264篇 |
1977年 | 185篇 |
1976年 | 167篇 |
1975年 | 191篇 |
1974年 | 253篇 |
1973年 | 195篇 |
1972年 | 203篇 |
1971年 | 169篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
LYSOSOMAL IRON ACCUMULATION AND TUBULAR DAMAGE IN RAT PUROMYCIN NEPHROSIS AND AGEING 总被引:1,自引:0,他引:1
David C. H. Harris Ching Tay Brian J. Nankivell 《Clinical and experimental pharmacology & physiology》1994,21(2):73-81
1. Energy dispersive X-ray spectrometry was used to examine the relationship between proteinuria and increased urinary iron excretion, and structural and functional damage in puromycin nephrosis. 2. After 11–12 days rats treated with puromycin (10 mg/100g, i.v.i.) had greater proteinuria (211.6 ± 35.7 mg/day, mean ± s.e.m.) and urinary iron excretion (15.4 ± 2.2 μg/day) than salinetreated controls (14.5 ± 1.4 mg/day and 1.1 ± 0.2 μg/day, respectively, both P<0.001). 3. On day 13, mean lysosomal iron concentration of proximal tubular cells (306.6 ± 64.5 vs 11.9 ± 8.6 mg%, P<0.001), and proximal tubular cell damage assessed semi-quantitively (1.17 ± 0.10 vs 0.62 ± 0.10, P<0.001) were higher and creatinine clearance (0.15 ± 0.01 vs 0.29 ± 0.02 mL/min perg kidney weight, P<0.001) lower than in control rats. 4. At days 35, 60 and 360 there were no differences in any of the measured parameters between rats treated with puromycin or saline, and in both groups proteinuria, tissue damage and lysosomal iron concentration increased with time. 5. Lysosomal iron accumulation was the only independent predictor of both functional and structural damage. 6. In conclusion, the apparent association between proteinuria and tubulo-interstitial damage in puromycin nephrosis, and with ageing, is best explained by factors associated with accumulation of iron within lysosomes of proximal tubule cells. 相似文献
32.
Summary Neurofibromatosis is sometimes complicated by impaired renal tubular reabsorption of phosphate, hypophosphatemia, and osteomalacia.
Hyperparathyroidism has also been reported in patients with neurofibromatosis. When hypercalcemia and elevated levels of parathyroid
hormone are found in osteomalacia, however, it may be difficult to determine if the hyperparathyroidism was primary or tertiary.
We describe a patient with neurofibromatosis, hypercalcemic hyperparathyroidism, hypophosphatemic osteomalacia, vitamin D
deficiency, and clear-cell hyperplasia of all four parathyroid glands. Serial biomechanical, bone biopsy, and densitometric
studies confirmed that treatment with ergocalciferol, calcium, and phosphate supplements significantly improved the osteomalacia
but caused increased parathyroid overactivity. After subtotal parathyroidectomy, the parathyroid hormone concentration became
normal and the bone mineral content increased at the spine and hip, but inappropriate phosphaturia persisted. The findings
indicate that hyperparathyroidism, osteomalacia, and vitamin D deficiency adversely affect each other. 相似文献
33.
In this study 112 patients (122 lower limbs) who had chronic venous stasis ulceration refractory to conservative management were treated surgically. Subfascial ligation was performed on 118 limbs and the long saphenous vein was removed in 4. Complications consisted of postoperative thrombophlebitis (2%), wound infection (2%) and wound infection with ulcer necrosis (1.5%). These all responded to conservative management. Follow-up (mean 7.9 years, median 11 years) showed a good or excellent result in 82% of cases, with healing of the ulcer and no ulcer recurrence despite significant noncompliance with support stockings. This paper is a long-term follow-up study of a surgical procedure for chronic venous stasis ulcers. The authors believe that the 82% good and excellent results may indicate that surgical intervention for refractory venous ulcers is a worthwhile procedure, providing potentially satisfactory long-term results. 相似文献
34.
35.
? Head and neck squamous cell carcinoma (HNSCC) represents the sixth most common tumour worldwide. ? Tumour hypoxia and anaemia are both independent prognostic indicators of disease free and overall survival in solid tumours, including HNSCC. ? Hypoxia promotes tumour progression through the hypoxia inducible factor 1 pathway (HIF‐1), upregulating factors that control angiogenesis, glycoloysis, pH regulation, erythropoiesis and apoptosis. ? Oxygen delivery to tumours is influenced by the oxygen carrying capacity of the blood, and therefore anaemia may promote tumour hypoxia. ? Targeting the HIF‐1 pathway and anaemia represent potential therapeutic targets in HNSCC and other solid tumours. 相似文献
36.
目的由于卒中风险随着狭窄严重程度的增加而升高,因此认为颈内动脉(ICA)接近闭塞患者的卒中风险很高。在现有的随机试验中,还没有专门针对这种情况进行探讨,因此其处理尚存在争汶。方法:对相关文献进行系统评价。结果:对ICA接近闭塞患者的处理还存在争议:一些学者支持进行干预,而另一些学者则认为存在风险或没有益处而反对进行干预。在ICA接近闭塞的有症状患者中进行一项比较外科治疗与最佳内科治疗的多中心前瞻性随机试验似乎非常困难,因为这类研究需要大量的患者。尽管如此,基于目前的证据,似乎很难拒绝手术治疗。结论:由于目前对ICA接近闭塞患者的最佳处理方案仍存在着争议,因此需要前瞻性观察性研究以证实其在有症状和无症状人群中的患病率以及相关的卒中风险。基于目前的证据,大多数医疗中心选择手术治疗,但它相对干内科治疗的特粱尚右待证章. 相似文献
37.
38.
The optimal extent of resection for patients with stages I or II breast cancer treated with conservative surgery and radiotherapy. 下载免费PDF全文
F A Vicini T J Eberlein J L Connolly A Recht A Abner S J Schnitt W Silen J R Harris 《Annals of surgery》1991,214(3):200-205
The optimal extent of breast resection before irradiation for treatment of early breast cancer has not been defined. Increasing the size of the resection may decrease the risk of local recurrence but will also have an adverse impact on the cosmetic outcome. The 5-year likelihood of a recurrence of the tumor was analyzed in relation to the volume of resected breast tissue in 507 patients with infiltrating ductal carcinoma treated with conservative surgery and radiation therapy between 1968 and 1982. Patients were stratified by clinical T-stage and for each T-stage patients were divided into three groups of equal numbers based on the volume of excised tissue. All patients had at least a gross excision of the tumor and the extent of breast resection was determined at the discretion of the surgeon without knowledge of the histologic features of the tumor. The median follow-up time was 100 months. The 5-year actuarial recurrence rates were analyzed in relation to clinical T-stage (T1 or T2) and the presence or absence of an extensive intraductal component (EIC+ or EIC-). For patients with EIC+ tumors, the largest resections were associated with a substantially lower risk of recurrence in the breast than the smallest resections. This effect was seen both for T1 tumors (10% versus 29%, p = 0.07) and for T2 tumors (9% versus 36%, p = 0.04). For patients with EIC-tumors, recurrence rates were significantly lower than for EIC+ tumors and were not influenced by the volume of resection to the same degree as EIC+ tumors. In the absence of an EIC, recurrence rates for the largest and smallest resections were 0% and 9% (p = 0.02) for T1 tumors and 3% and 6% (p = NS) for T2 tumors. It is concluded that a limited breast resection is acceptable for an EIC- tumor but that a more extensive resection is required for an EIC+ tumor. These results stress the importance of assessing the presence or absence of an EIC in determining the optimal extent of breast resection required before radiation therapy. 相似文献
39.
N. C. Harris S. A. Greenfield 《Journal of neural transmission (Vienna, Austria : 1996)》1991,3(2):89-98
Summary Intracellular recordings were made from substantia nigra pars compacta neurones in vitro from animals with partial unilateral 6-hydroxydopamine lesions of the nigrostriatal tract. Lesions were assessed and grouped according to the severity of the strital dopamine depletion. No differences were seen between neurones from control and lesioned side nigrae as regards their membrane properties, firing rates, burst activity or percentage of quiescent neurones in any of the lesioned categories. It is concluded that following partial lesioning, the remaining substantia nigra zona compacta neurones in vitro, are functioning normally. 相似文献
40.
Carrier diagnosis of Duchenne muscular dystrophy using restriction fragment length polymorphisms 总被引:6,自引:0,他引:6
Molecular probes that are tightly linked to and flank the Duchenne muscular dystrophy (DMD) locus, have been used to characterize DMD mutations and diagnose female carriers. Deletions within the Xp21 region were identified for 8 of 71 families studied. Using both DNA and CK studies, accurate (96 to 98%) carrier or noncarrier diagnoses were made for 51 of 75 females at risk in 24 families with a single affected male. DNA studies resulted in an alteration of predicted risk in 40% of the cases. Recombinant diagnostic methods are useful for carrier detection in families with one or more affected males. 相似文献