全文获取类型
收费全文 | 4758篇 |
免费 | 392篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 84篇 |
儿科学 | 138篇 |
妇产科学 | 49篇 |
基础医学 | 688篇 |
口腔科学 | 73篇 |
临床医学 | 558篇 |
内科学 | 831篇 |
皮肤病学 | 104篇 |
神经病学 | 526篇 |
特种医学 | 243篇 |
外国民族医学 | 1篇 |
外科学 | 729篇 |
综合类 | 28篇 |
一般理论 | 2篇 |
预防医学 | 350篇 |
眼科学 | 107篇 |
药学 | 335篇 |
中国医学 | 5篇 |
肿瘤学 | 315篇 |
出版年
2023年 | 67篇 |
2022年 | 90篇 |
2021年 | 244篇 |
2020年 | 147篇 |
2019年 | 213篇 |
2018年 | 241篇 |
2017年 | 170篇 |
2016年 | 169篇 |
2015年 | 201篇 |
2014年 | 242篇 |
2013年 | 280篇 |
2012年 | 372篇 |
2011年 | 359篇 |
2010年 | 209篇 |
2009年 | 174篇 |
2008年 | 233篇 |
2007年 | 222篇 |
2006年 | 185篇 |
2005年 | 123篇 |
2004年 | 135篇 |
2003年 | 95篇 |
2002年 | 79篇 |
2001年 | 29篇 |
2000年 | 28篇 |
1999年 | 29篇 |
1998年 | 37篇 |
1997年 | 41篇 |
1996年 | 47篇 |
1995年 | 38篇 |
1994年 | 36篇 |
1993年 | 21篇 |
1992年 | 32篇 |
1991年 | 50篇 |
1990年 | 28篇 |
1989年 | 45篇 |
1988年 | 50篇 |
1987年 | 43篇 |
1986年 | 37篇 |
1985年 | 48篇 |
1984年 | 31篇 |
1983年 | 19篇 |
1982年 | 24篇 |
1981年 | 21篇 |
1980年 | 15篇 |
1979年 | 17篇 |
1978年 | 14篇 |
1977年 | 10篇 |
1976年 | 12篇 |
1975年 | 13篇 |
1974年 | 11篇 |
排序方式: 共有5166条查询结果,搜索用时 234 毫秒
991.
Monica Sheth Umairullah Lodhi Brandon Chen Young Park Suzanne McElligott 《Journal of ultrasound in medicine》2019,38(10):2769-2776
Cryoablation is a safe and effective nonsurgical treatment for breast fibroadenomas (FAs). The treatment response is inversely related to the tumor size, with lesions less than 2 cm showing an optimal response. Ultrasound (US) imaging follow‐up of the ablated tumor is recommended at 6‐month intervals for 2 years at our institution. Although a decrease in the size of the FA clinically and on US imaging is the expected treatment response, variations can be seen. Knowledge of typical US changes over time is imperative to prevent unnecessary rebiopsy or excision in patients who have undergone cryoablation. We will review the initial patient selection criteria, cryoablation technique, and US findings at regular follow‐up intervals after cryoablation of FAs through a series of cases treated at our institution. 相似文献
992.
The tissue distribution and immunochemical properties of antigens recognized by two monoclonal antibodies 1.11.32 and 1.28.124 define the sheep analogue of the leucocyte common antigen found in rat, man and mouse. Histological and immunofluorescent studies show that this antigen is found on all lymphocytes, as well as other leucocytes but is absent from non-leucocytic cells. Immunochemical data show that a series of proteins of high molecular weight (190,000-225,000) are recognized, and histological studies show the presence of this antigen on a subpopulation of fetal liver cells as early as Day 27-30 of gestation, and on all fetal thymocytes from Day 40 of gestation. 相似文献
993.
Kucharczyk W; Brant-Zawadzki M; Sobel D; Edwards MB; Kelly WM; Norman D; Newton TH 《Radiology》1985,155(1):131-136
Fifty-one pediatric patients who were suspected of having central nervous system (CNS) tumors underwent magnetic resonance (MR) imaging using a 0.35 T Diasonics MT/S system. Pulse intervals (TR) ranged from 0.5 to 2.0 seconds with echo delays (TE) of 28 and 56 msec. The ability of MR and contrast-enhanced CT to detect focal lesions, determine lesion extent, and evaluate associated abnormalities was compared. In most patients in whom there was suspected spinal cord disease, comparison with myelography was made. Thirty-three intracranial lesions were detected with at least one imaging modality in 43 cranial examinations. MR was judged superior to CT in 14 of these cases and CT superior to MR in only one. Of eight spinal examinations, there were six that demonstrated abnormal findings. MR was superior to CT in all six cases and better than myelography in four of five cases where myelography was performed. Spin echo (SE) sequences with long pulse intervals were the most sensitive, but in some cases short pulse intervals permitted further characterization of the lesion. Patient motion was not a problem; sedation was routinely used in children younger than five years of age. MR imaging has rapidly become a valuable diagnostic modality in neuroradiology. The lack of ionizing radiation and the ability to evaluate the spinal cord noninvasively makes it particularly attractive in examination of children. 相似文献
994.
Ocular and orbital lesions: surface coil MR imaging 总被引:1,自引:0,他引:1
Bilaniuk LT; Schenck JF; Zimmerman RA; Hart HR Jr; Foster TH; Edelstein WA; Goldberg HI; Grossman RI 《Radiology》1985,156(3):669-674
Nine lesions, four ocular (three melanomas, one hemangioma) and five orbital (two perioptic meningiomas, one hemangioma, one pseudotumor, one mucocele), were evaluated by magnetic resonance surface coil imaging at 1.5 T. Small ocular lesions with 3.9-4.5-mm-elevation were demonstrated. The use of two different pulse sequences resulted in separation of melanoma from adjacent retinal detachment. Contrast obtained between orbital lesions and the adjacent normal structures was better than that demonstrated with high-resolution computed tomography. 相似文献
995.
996.
Integration of bovine leukaemia virus in the ovine genome 总被引:1,自引:0,他引:1
Circulating lymphocytes and tumour cells from 12 sheep experimentally infected with bovine leukaemia virus (BLV), for periods of time varying from 9 to 48 weeks, were analysed for evidence of integrated and unintegrated provirus. Hybridization analysis demonstrated that the provirus was integrated at one or two sites in all cases. Integration was observed at different sites in the animals studied and there was no evidence of unintegrated virus molecules in infected sheep lymphocytes or tumour cells. The data obtained support a monoclonal origin of different tumours in the same sheep. 相似文献
997.
Pituitary adenomas: high-resolution MR imaging at 1.5 T 总被引:3,自引:0,他引:3
The magnetic resonance (MR) images of 28 patients with surgically confirmed pituitary adenomas were retrospectively evaluated. The examinations were performed on a 1.5-T superconducting MR system using a multisection spin-echo technique with 3-mm-thick sections and a 256 X 256 matrix. T1- and T2-weighted images were obtained in sagittal and coronal planes. The MR findings were correlated with detailed operative reports and diagrams. There were 11 microadenomas and 17 macroadenomas. Ten of the microadenomas and all of the macroadenomas were accurately localized and their extent delineated, particularly on T1-weighted coronal sections. Adenomas typically appeared hypointense on T1-weighted coronal sections. The appearance on T2-weighted images was variable, and generally the lesions were less well seen. Involvement of parasellar structures, particularly the optic chiasm and cavernous sinuses, was accurately depicted. Cyst formation and hemorrhage could be characterized in some instances. In general, there was excellent correlation between MR imaging and operative findings. 相似文献
998.
999.
Lymphocyte subsets show marked differences in their distribution between blood and the afferent and efferent lymph of peripheral lymph nodes 总被引:6,自引:1,他引:5 下载免费PDF全文
C R Mackay W G Kimpton M R Brandon R N Cahill 《The Journal of experimental medicine》1988,167(6):1755-1765
The surface phenotypes (CD1, CD4, CD5, CD8, SBU-T19, MHC class I, MHC class II, and sIg) of cells in blood, lymph nodes, and lymph were determined to examine simultaneously the distribution of lymphocyte subsets circulating in blood, afferent lymph, and efferent lymph of a peripheral lymph node. Marked differences in the percentage of certain lymphocyte subsets were apparent within the compartments examined, suggesting that lymphocyte subsets leave the blood with differing efficiencies. Lymphocyte subsets also appeared to be extracted from the blood at different rates by lymph node as opposed to subcutaneous vascular endothelium. Endothelial cells in different vascular beds may express different numbers of molecules complementary to a set of migration-related cell surface molecules specific for each lymphocyte subset. Accordingly, the vascular endothelium would be the key factor in regulating nonrandom cell migration. 相似文献
1000.