全文获取类型
收费全文 | 5867篇 |
免费 | 247篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 87篇 |
儿科学 | 572篇 |
妇产科学 | 145篇 |
基础医学 | 607篇 |
口腔科学 | 76篇 |
临床医学 | 343篇 |
内科学 | 1285篇 |
皮肤病学 | 47篇 |
神经病学 | 257篇 |
特种医学 | 357篇 |
外科学 | 849篇 |
综合类 | 116篇 |
一般理论 | 4篇 |
预防医学 | 229篇 |
眼科学 | 102篇 |
药学 | 479篇 |
中国医学 | 30篇 |
肿瘤学 | 544篇 |
出版年
2023年 | 35篇 |
2022年 | 80篇 |
2021年 | 177篇 |
2020年 | 83篇 |
2019年 | 137篇 |
2018年 | 154篇 |
2017年 | 123篇 |
2016年 | 149篇 |
2015年 | 171篇 |
2014年 | 220篇 |
2013年 | 310篇 |
2012年 | 439篇 |
2011年 | 504篇 |
2010年 | 291篇 |
2009年 | 279篇 |
2008年 | 351篇 |
2007年 | 344篇 |
2006年 | 345篇 |
2005年 | 321篇 |
2004年 | 288篇 |
2003年 | 203篇 |
2002年 | 220篇 |
2001年 | 60篇 |
2000年 | 70篇 |
1999年 | 60篇 |
1998年 | 50篇 |
1997年 | 52篇 |
1996年 | 48篇 |
1995年 | 25篇 |
1994年 | 24篇 |
1993年 | 21篇 |
1992年 | 36篇 |
1991年 | 47篇 |
1990年 | 36篇 |
1989年 | 45篇 |
1988年 | 35篇 |
1987年 | 32篇 |
1986年 | 19篇 |
1985年 | 31篇 |
1984年 | 21篇 |
1983年 | 18篇 |
1982年 | 10篇 |
1981年 | 17篇 |
1979年 | 20篇 |
1978年 | 11篇 |
1977年 | 10篇 |
1975年 | 17篇 |
1974年 | 10篇 |
1970年 | 9篇 |
1967年 | 11篇 |
排序方式: 共有6129条查询结果,搜索用时 15 毫秒
51.
N. V. Krishna S. K. Bhatnagar D. L. Chhangani 《Indian journal of otolaryngology and head and neck surgery》1981,33(3):107-108
Ameloblastoma is the most frequently seen epithelial Odontogenic tumour, relatively uncommon, comprising about 1% of tumours and cysts arising from the Jaws. 相似文献
52.
M J Meaney J B Mitchell D H Aitken S Bhatnagar S R Bodnoff L J Iny A Sarrieau 《Psychoneuroendocrinology》1991,16(1-3):85-103
Several years ago Levine, Denenberg, Weininger, Ader, and others described the effects of postnatal "handling" on the development of behavioral and endocrine responses to stress. The handling procedure usually involved removing rat pups from their cages, placing the animals together in small containers, and 15-20 min later, returning the animals to their cages and their mothers. The manipulation was performed daily for the first 21 days of life. As adults, handled (H) rats exhibited attenuated fearfulness (e.g., decreased freezing, increased exploration) in novel environments and a less pronounced increase in the secretion of adrenal glucocorticoids in response to a variety of stressors. These findings clearly demonstrated that the development of rudimentary, adaptive responses to stress could be modified by environmental events. We have followed on these earlier handling studies, convinced that this paradigm provides a marvelous opportunity to examine how subtle variations in the early environment alter the development of specific biochemical systems in the brain, leading to stable individual differences in biological responses to stimuli that threaten homeostasis. In this work we have shown how early handling influences the neurochemical development of certain brain regions that regulate the adrenocortical response to stress. Neonatal handling increases the efficiency of this endocrine response to stress, preventing excessive exposure to the highly catabolic adrenal steroids. In later life, this effect appears to protect the animal from potentially damaging effects of these steroids, ensuring the anatomical integrity of brain structures involved in cognitive functioning. 相似文献
53.
Preeti Sharma Subha Rastogi Sunita Bhatnagar Janmejya K. Srivastava Anuradha Dube Purushottam Y. Guru Dinesh K. Kulshrestha Bishan N. Mehrotra Bhola N. Dhawan 《Drug development research》2003,60(4):285-293
Tephrosia purpurea (family: Fabaceae), which is used in traditional remedies for the treatment of febrile attacks, enlargement and obstruction of liver, spleen, and kidney, was found to have significant antileishmanial activity, and has been extensively fractionated to locate the abode of activity. A fraction (F062) obtained from N‐butanol extract of T. purpurea showed consistent antileishmanial activity at 50 mg/ kg × 5 days by oral route against Leishmania donovani infection in hamsters. Activity was further confirmed in a secondary model, i.e., Indian langur monkeys (Presbytis entellus). Thus, the fraction F062 from this plant possesses potential to produce significant antileishmanial activity by oral route without producing any toxic side effects. Drug. Dev. Res. 60:285–293, 2003. © 2003 Wiley‐Liss, Inc. 相似文献
54.
Dayananda S Sharma Rakesh Jalali Chandrashekhar M Tambe Deepak D AnimeshDeshpande 《Radiotherapy and oncology》2004,70(1):49-54
BACKGROUND AND PURPOSE: The aim of this work was to measure the dose to foetus both in vivo and in vitro during three-dimensional conformal radiation therapy (3DCRT) in a pregnant patient with a pituitary adenoma. The study was then extended to assess the components contributing to the foetal dose such as collimator scatter, internal scatter, head leakage, wedge scatter and multileaf collimator (MLC) effect. PATIENTS AND METHODS: A 30-year-old pregnant woman with a non-functioning pituitary macroadenoma was planned for 3DCRT with 6MV X-ray using four equally weighted MLC-shaped non-coplanar wedged portals. In vivo dosimetry was carried out using thermoluminescent (TL) phosphor powder, which was placed at different positions on the patient, corresponding to different locations in the uterus and also at external os. In vitro measurements were also performed on a simulated phantom using the same set-up parameters and beam arrangement to verify the in vivo measured dose. Experiments were carried out to measure the respective contributions of different components towards peripheral dose. RESULTS: In vitro measured dose to foetus was found to be slightly more than that of in vivo measurement with a maximum of 0.044% of the prescribed dose of 45Gy, which corresponded to 0.0199+/-0.0008Gy. Thermoluminescence dosimeter (TLD) kept at the external os of the patient showed a dose of 0.031% of the prescribed dose. Among the various components of the peripheral dose (foetal dose) measured, head leakage was found to be the leading cause contributing 52%, followed by wedge scatter (31%), collimator scatter (14%) and internal scatter (13%). The use of MLC reduced not only the volume of normal brain irradiation as compared to open fields but also the peripheral dose by 10%. CONCLUSION: Radiotherapy of brain tumours during pregnancy poses a unique clinical situation and decisions to deliver radiotherapy should be taken after detailed in vitro and in vivo dosimetric measurements. Our findings suggest that the beam arrangement using 3-4-fields generally used for 3DCRT of brain tumour with MLC for optimal coverage can be employed for pregnant patients even in early trimester. A possible increase in foetal dose from wedges to a large extent can be compensated with the use of MLC. 相似文献
55.
The p21-activated kinases signal through a number of cellular pathways fundamental to growth, differentiation and apoptosis.
A wealth of information has accumulated at an impressive pace in the recent past, both with regard to previously identified
targets for p21-activated kinases that regulate the actin cytoskeleton and cellular stress pathways and with regard to newly
identified targets and their role in cancer. Emerging data also provide new clues towards a previously unappreciated link
between these various cellular processes. The present review attempts to provide a quick tutorial to the reader about the
evolving significance of p21-activated kinases and small GTPases in breast cancer, using information from mouse models, tissue
culture studies, and human materials. 相似文献
56.
PURPOSE: Approximately two-thirds of breast cancer patients respond to endocrine therapy, and this population of patients is estrogen receptor (ER) positive. However, a significant proportion of patients do not respond to hormone therapy. ER hormone responsiveness is widely believed to be influenced by enhanced cross-talk of ER with overexpressed human epidermal growth factor receptor 2 (HER2), and a subgroup of ER-positive tumors coexpress high HER2. EXPERIMENTAL DESIGN: Breast cancer cells with or without HER2 overexpression were analyzed for ER status, subcellular localization, and interactions with HER2 signaling components by biochemical and immunological methods. Experiments explored the regulatory interactions between the HER2 and ER pathways and the sensitivity of breast cancer cells to tamoxifen. RESULTS: Stable or transient or natural HER2 overexpression in ER-positive breast cancer cells promoted the nucleus-to-cytoplasm relocalization of ER, enhanced interactions of ER with HER2, inhibited ER transactivation function, and induced resistance to tamoxifen-mediated growth inhibition of breast cancer cells. In addition, HER2 up-regulation resulted in ER interaction with Sos, a component of Ras signaling, and hyperstimulation of the mitogen-activated protein kinase extracellular signal-regulated kinase 1/2 (ERK1/2). Conversely, down-regulation of HER2 by the anti-HER2 monoclonal antibody Herceptin led to suppression of ERK1/2 stimulation, restoration of ER to the nucleus, and potentiation of the growth-inhibitory action of tamoxifen. CONCLUSION: The results presented here show for the first time that ER redistribution to the cytoplasm and its interaction with HER2 are important downstream effects of HER2 overexpression, that ERK1/2 is important for ER cytoplasmic localization, and that subcellular localization of ER may play a mechanistic role in determining the responsiveness of breast cancer cells to tamoxifen. 相似文献
57.
Vedang Murthy Jai Prakash Agarwal Rakesh Jalali Roshni F Chinoy 《Journal of Medical Imaging and Radiation Oncology》2003,47(2):202-204
Solitary extramedullary plasmacytoma is a rare tumour with radiotherapy playing an important role in its management. This report describes the case history of a man with a solitary extramedullary plasmacytoma at an extremely rare site, the premaxilla, that posed certain diagnostic and therapeutic dilemmas. The patient underwent surgery followed by postoperative radiotherapy. The use of two modalities of treatment for this localized tumour has been justified by briefly reviewing the literature and defining the various prognostic factors. These prognostic factors in turn should guide the treatment of these uncommon tumours. 相似文献
58.
59.
60.
M. Srinivas S. Agarwala A. K. Padhy A. K. Gupta M. Bajpai V. Bhatnagar D. K. Gupta D. K. Mitra 《Pediatric surgery international》1998,14(3):185-188
Solitary kidneys in renal donors and patients who have undergone unilateral nephrectomy for malignant disease have been reported
to undergo hyperfiltration injury. This study was undertaken to evaluate the somatic growth and development of followed-up
patient after Wilms' tumor to evaluate their renal function and identify any evidence of injury in the remaining kidney. The
growth and development of all the children was found to be normal, as was DTPA clearance. Microalbuminuria in 24-h urinary
collections was detected in 84% of the patients, indicating evidence of hyperfiltration injury. This study highlights the
need for close monitoring of the renal function of long-term follow-up patients after Wilms' tumor in addition to the routine
monitoring for tumor recurrence.
Accepted: 26 May 1998 相似文献