全文获取类型
收费全文 | 528396篇 |
免费 | 39352篇 |
国内免费 | 16339篇 |
专业分类
耳鼻咽喉 | 6286篇 |
儿科学 | 13594篇 |
妇产科学 | 8740篇 |
基础医学 | 62378篇 |
口腔科学 | 13812篇 |
临床医学 | 51850篇 |
内科学 | 69156篇 |
皮肤病学 | 9354篇 |
神经病学 | 30103篇 |
特种医学 | 12379篇 |
外国民族医学 | 150篇 |
外科学 | 51998篇 |
综合类 | 79381篇 |
现状与发展 | 66篇 |
一般理论 | 30篇 |
预防医学 | 40951篇 |
眼科学 | 8993篇 |
药学 | 45977篇 |
436篇 | |
中国医学 | 36666篇 |
肿瘤学 | 41787篇 |
出版年
2024年 | 1512篇 |
2023年 | 8135篇 |
2022年 | 14595篇 |
2021年 | 20241篇 |
2020年 | 18453篇 |
2019年 | 23973篇 |
2018年 | 21839篇 |
2017年 | 19240篇 |
2016年 | 17028篇 |
2015年 | 17279篇 |
2014年 | 30696篇 |
2013年 | 33726篇 |
2012年 | 28538篇 |
2011年 | 31321篇 |
2010年 | 25534篇 |
2009年 | 23694篇 |
2008年 | 23860篇 |
2007年 | 24452篇 |
2006年 | 21702篇 |
2005年 | 19311篇 |
2004年 | 16383篇 |
2003年 | 14323篇 |
2002年 | 11545篇 |
2001年 | 10247篇 |
2000年 | 8485篇 |
1999年 | 7415篇 |
1998年 | 6558篇 |
1997年 | 6149篇 |
1996年 | 5409篇 |
1995年 | 4986篇 |
1994年 | 4628篇 |
1993年 | 3779篇 |
1992年 | 3481篇 |
1991年 | 3123篇 |
1990年 | 2631篇 |
1989年 | 2387篇 |
1988年 | 2235篇 |
1987年 | 1849篇 |
1986年 | 1736篇 |
1985年 | 4736篇 |
1984年 | 5606篇 |
1983年 | 3897篇 |
1982年 | 4392篇 |
1981年 | 4019篇 |
1980年 | 3548篇 |
1979年 | 3197篇 |
1978年 | 2719篇 |
1977年 | 2050篇 |
1976年 | 2263篇 |
1975年 | 1678篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Rats having either sham operations or one-stage bilateral lesions of the two somatosensory areas of the cortex were tested for acquisition of five tactile discriminations after postoperative recovery intervals of 14, 35, 180, 365 or 730 days. The group with lesions performed worse than its time-matched control group in every instance, and there was no evidence for recovery of function with the longer postoperative recovery periods. These results suggest that time per se is not a significant determinant of restitution after somatosensory cortical ablations. 相似文献
992.
Helen J. Cooke John Atherton Young 《Pflügers Archiv : European journal of physiology》1970,318(4):315-324
Summary Techniques have been developed for collection of urine in embryonic and newly hatched chickens for the purpose of studying the development of renal function.The reliability of EDTA-51Cr as a substitute for inulin-14C in the determination of GFR was studied. Since inulin and EDTA-51Cr clearances in the hatched chicken averaged 1.61±0.23 (S.E.) ml/min per kg body weight and 1.58±0.27 ml/min per kg body weight, respectively, EDTA-51Cr clearance was considered a suitable measure of GFR.GFR increased significantly in the first few days after hatching. Filtration rate was 0.068±0.008 (S.E.) ml/min per g kidney weight in the embryo and increased to 0.148±0.008 ml/min per g shortly after hatching. By nine days after hatching GFR had risen to 0.290±0.015 ml/min per g, a value comparable to that reported for the adult.Clearances of sodium, potassium, chloride and total osmolyte also increased with age. When these clearances were corrected for changing glomerular filtration rates the embryonic chicks were found to excrete a greater percentage of the filtered load. These results show that adult levels of glomerulo-tubular balance are not attained until after hatching.A preliminary report of this work has already been published [3]. 相似文献
993.
Specific antibody production and the proliferative response of peripheral blood lymphocytes (PBLs) to a variety of viruses, including herpes simplex virus-type-1 (HSV-1) and varicella zoster (VZ), were studied in 7 patients with Behçet's syndrome. None of the patients produced an antibody response against HSV-1 or VZ. Furthermore, none of the patients showed a proliferative response to VZ, and three of them also failed to mount a response to HSV-I. These results suggest that the PBLs of patients with Behçet's syndrome make an inappropriately poor antibody and proliferative response when stimulated by HSV-1 and VZ. 相似文献
994.
995.
Logan Banner Rao Ernstoff Wolmark Whiteside Miketic Kirkwood 《Clinical and experimental immunology》1998,114(3):347-354
A patient with von Hippel Lindau disease, bilateral symmetric renal cell carcinoma and pulmonary metastases treated with immunotherapy is the subject of this study. A left kidney and tumour mass were removed and the tumour cells used to make an autologous tumour/bacille Calmette–Guérin (BCG) vaccine as part of the treatment protocol. The patient's pulmonary nodules responded, but the remaining renal nodule subsequently grew. Samples of both tumours were obtained allowing for an internally controlled evaluation of the histological and immunohistologic differences between a responding and non-responding tumour nodule after therapy. The immunotherapy protocol is designed to promote a T cell response to autologous tumour. Cellular infiltrates were demonstrated in both responding and non-responding nodules compared with the pretreatment tumour specimen, but the responding nodule contained proportionately more T cells as well as markedly increased numbers of plasma cells and granulocytes. This suggested that several arms of the immune system may have been operative in the responding nodule. 相似文献
996.
We often see perilobular necrosis of the pancreas in patients with liver disease at autopsy. This study was undertaken to determine the frequency and the mechanism of development of pancreatic perilobular necrosis in patients with liver disease. Pancreatic perilobular necrosis was seen in 21 per cent of 261 autopsied patients: in 41 per cent of 73 autopsied patients with liver disease and in 13 per cent of 188 autopsied patients without liver disease. Moreover, splanchnic congestion was present in 90 per cent of 30 pancreatic perilobular necrosis patients with liver disease. These data indicate that patients with liver disease develop perilobular necrosis of the pancreas more often than patients without liver disease, and that the high frequency may be a sequela of splanchnic congestion; that is, congestion of the pancreas and endotoxaemia due to congestion of the gut. 相似文献
997.
Distinguishing characteristics of a new neuroblastoma cell line 总被引:3,自引:0,他引:3
J T Casper J M Trent J Harb V Piaskowski M Helmsworth J Finlan D D Von Hoff 《Cancer Genetics and Cytogenetics》1983,10(2):177-186
The characteristics of a new neuroblastoma cell line (MC-NB-1) established from the bone marrow of a 2-year-old male are described. Morphologically, the cells appear as flattened and epithelial-like or as small and spherical. Electron microscopy demonstrated microtubules and dense core secretory granules. The doubling time was approximately 35 hr. Isoenzyme patterns and catecholamine secretion indicated a human line of neuronal origin. The soft agar tumor colony forming system demonstrated drug resistance in vitro comparable to in vivo nonresponsiveness. The stemline karyotype of MC-NB-1 is 44,Y,del(1) (p22:), -4, -7, +del(7)(q22:), -16, +t(7;16)(16pter leads to 16q24::7q22 leads to 7q32), -17. Additionally, double-minute bodies were observed. However, no evidence of homogeneous staining regions (HSRs) were detected. 相似文献
998.
Three judges were trained to evaluate the frequency, intensity, and duration of aggressive responses in rats. Intrajudge and interjudge reliability ranged from .84 to .99. Correlation coefficients between frequency, intensity, and duration of aggressive responses ranged from .89 to .99. All three measures were found to be highly reliable methods of measuring aggression. 相似文献
999.
Correction of EOG Artifacts in Event-Related Potentials of the EEG: Aspects of Reliability and Validity 总被引:3,自引:0,他引:3
Correction of EOG artifacts using a regression approach is evaluated in terms of reliability and validity. Transmission rates are estimated for eight EEG channels in 67 subjects. The trimmed group means of these rates are shown to provide reliable measures. Eye artifact correction based on these group means is superior to the conventional rejection in terms of reducing correlation between EOG and EEG. 相似文献
1000.
Accumulating evidence indicates that tumor viruses represent a major etiological factor in a significant portion of human cancers. These cancers include human papillomavirus induced anogenital cancers, hepatitis B and C virus associated hepatocellular carcinomas, nasopharyngeal carcinomas and lymphomas linked to Epstein-Barr virus infection, and human T cell leukemia virus associated adult T cell leukemias. This review summarizes the recent progress made in understanding the molecular mechanisms of viral carcinogenesis, with a particular focus on the interaction of viral factors with cellular tumor suppressor proteins. The functional inactivation of tumor suppressor proteins may represent a common strategy by which several tumor viruses contribute to malignant cell transformation.Abbreviations
EBV
Epstein-Barr virus
-
E6AP
E6-associated protein
-
HBV
Hepatitis B virus
-
HCC
Hepatocellular carcinoma
-
HPV
Human papillomavirus
-
HTLV
Human T cell leukemia virus
-
pRb
Retinoblastoma protein
-
RB
Retinoblastoma
-
SV40
Simian virus 40 相似文献