全文获取类型
收费全文 | 9000篇 |
免费 | 901篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 214篇 |
妇产科学 | 164篇 |
基础医学 | 1283篇 |
口腔科学 | 224篇 |
临床医学 | 972篇 |
内科学 | 1842篇 |
皮肤病学 | 90篇 |
神经病学 | 972篇 |
特种医学 | 499篇 |
外科学 | 1076篇 |
综合类 | 307篇 |
一般理论 | 2篇 |
预防医学 | 882篇 |
眼科学 | 268篇 |
药学 | 549篇 |
中国医学 | 46篇 |
肿瘤学 | 473篇 |
出版年
2021年 | 150篇 |
2020年 | 96篇 |
2019年 | 145篇 |
2018年 | 150篇 |
2017年 | 122篇 |
2016年 | 123篇 |
2015年 | 147篇 |
2014年 | 217篇 |
2013年 | 309篇 |
2012年 | 479篇 |
2011年 | 432篇 |
2010年 | 285篇 |
2009年 | 257篇 |
2008年 | 374篇 |
2007年 | 372篇 |
2006年 | 395篇 |
2005年 | 343篇 |
2004年 | 341篇 |
2003年 | 282篇 |
2002年 | 323篇 |
2001年 | 265篇 |
2000年 | 213篇 |
1999年 | 215篇 |
1998年 | 137篇 |
1997年 | 140篇 |
1996年 | 147篇 |
1995年 | 119篇 |
1994年 | 105篇 |
1993年 | 94篇 |
1992年 | 222篇 |
1991年 | 188篇 |
1990年 | 188篇 |
1989年 | 215篇 |
1988年 | 194篇 |
1987年 | 176篇 |
1986年 | 161篇 |
1985年 | 171篇 |
1984年 | 142篇 |
1983年 | 120篇 |
1982年 | 81篇 |
1981年 | 69篇 |
1980年 | 76篇 |
1979年 | 108篇 |
1978年 | 86篇 |
1977年 | 86篇 |
1975年 | 72篇 |
1974年 | 85篇 |
1973年 | 78篇 |
1972年 | 70篇 |
1970年 | 70篇 |
排序方式: 共有9921条查询结果,搜索用时 15 毫秒
61.
William E. Gillies FRACS FRACO FRCS Anne MV Brooks MD PhD FRACS FRACO FRACP 《Clinical & experimental ophthalmology》1996,24(3):169-187
Background: We have investigated the vascular perfusion of a wide variety of conditions of the anterior segment using fluorescein angiography.
Methods: The conditions were classified and findings reported according to the system set out below. Patients underwent full ocular examination. Fluorescein angiography of the anterior segment was carried out when indicated to investigate iris atrophy and neovascularisation. Specular microscopy of the corneal endothelium was used to detect changes in this tissue.
Results: The hypoperfusion was variable in degree and accompanied by varying degrees of iris hypoplasia and atrophy with neovascularisation. The degree of neovascularisation depended upon its rapidity of development, the pre-existing state of vascular perfusion and the underlying pathological condition.
Conclusions: Hypoperfusion with resultant ischaemia and neovascularisation is common in conditions of the anterior segment. An understanding of the changes is valuable in treating many conditions affecting the anterior segment. The changes observed may also occur elsewhere in the physical system and may be a significant part of the ageing process, either as scattered, disparate processes or as part of a general disease process. 相似文献
Methods: The conditions were classified and findings reported according to the system set out below. Patients underwent full ocular examination. Fluorescein angiography of the anterior segment was carried out when indicated to investigate iris atrophy and neovascularisation. Specular microscopy of the corneal endothelium was used to detect changes in this tissue.
Results: The hypoperfusion was variable in degree and accompanied by varying degrees of iris hypoplasia and atrophy with neovascularisation. The degree of neovascularisation depended upon its rapidity of development, the pre-existing state of vascular perfusion and the underlying pathological condition.
Conclusions: Hypoperfusion with resultant ischaemia and neovascularisation is common in conditions of the anterior segment. An understanding of the changes is valuable in treating many conditions affecting the anterior segment. The changes observed may also occur elsewhere in the physical system and may be a significant part of the ageing process, either as scattered, disparate processes or as part of a general disease process. 相似文献
62.
63.
Malanda Nsuami Migel Elie Bridget N Brooks Ladatra S Sanders Theresa D Nash Feseha Makonnen Stephanie N Taylor Deborah A Cohen 《The Journal of adolescent health》2003,32(5):336-339
In an urban school district, 636 students in grades 9-12 were tested for Chlamydia trachomatis and Neisseria gonorrhoeae by ligase chain reaction assays using specimens collected for routine urinalyses during sports physical examinations. Chlamydia and gonorrhea prevalences were 2.8% and 0.7% among males, and 6.5% and 2.0% among females, respectively. Among athletes infected with either sexually transmitted disease (STD), 93.1% reported no symptoms, and treatment was documented for 75.9%. Sports physicals offered a unique opportunity to screen and treat adolescents for STDs and to provide STD-prevention counseling. 相似文献
64.
Christine A. Ellis Susan F. Brooks Gavin Brooks A. Tudor Evans Nicholas Morrice Fred. J. Evans Alastair Aitken 《Phytotherapy research : PTR》1987,1(4):187-190
The sapintoxins are a series of naturally occurring fluorescent phorbol esters with a range of selective biological activities (e.g. pro-inflammatory but non-tumour promoting). Their ability to activate protein kinase C (PKC) in vitro has been studied. Both tumour promoting and non-promoting phorbol derivatives activate the enzyme in vitro at low concentrations. 12-deoxyphorbol-13-phenylacetate-20 acetate (DOPPA) acts as a partial agonist in the activation of protein kinase C. Structurally distinct phorbol esters may therefore preferentially activate different forms of protein kinase C. α-sapinine, a biologically inactive compound, binds to protein kinase C without stimulating the enzyme and prevents subsequent activation by phorbol esters such as 12-O-tetradecanoyl phorbol-13-acetate (TPA). 相似文献
65.
M P Slade A M Brooks W E Gillies 《Australian and New Zealand journal of ophthalmology》1989,17(4):445-450
Two cases are reported: a father and son with a new syndrome consisting of a severe congenital glaucoma associated with a form of palmoplantar keratoderma showing features of mutilating palmoplantar keratoderma. Both the glaucoma and keratoderma may be attributed to an autosomal dominantly inherited genetic mutation of a single chromosome affecting two tissues of neural crest origin, the ectodermal tissues of the hands and feet and the cranial mesenchyme from which the tissues of the chamber angle develop. Elucidation of the precise chromosomal abnormality causing these defects may help in understanding the inheritance and aetiology of glaucoma. 相似文献
66.
67.
The effect of a new dihydropyridine slow-channel calcium blocking agent, nisoldipine, on hemodynamics and myocardial blood flow in normal and collateral-dependent areas distal to a chronic coronary artery occlusion were studied in chronically instrumented, conscious dogs. Nisoldipine produced significant and dose-related decreases in arterial blood pressure, an elevation of heart rate and large increases in coronary blood flow velocity. In dogs with an Ameroid constrictor previously implanted to enhance coronary collateral development, this agent produced large increases in perfusion distal to a chronic coronary artery occlusion. In addition, despite a reduction in arterial pressure, nisoldipine preserved renal cortical, intestinal and skeletal muscle blood flow while increasing tissue flow within liver and cerebral cortex. Thus, nisoldipine increases oxygen supply to collateral-dependent myocardium in the presence of reduced driving pressure for collateral perfusion. 相似文献
68.
69.
A total of 1249 "cold" solitary thyroid nodules were excised at the Brigham and Women's Hospital from 1948 through 1987. Of these nodules, 241 showed malignant conditions: 123 were papillary, 42 were mixed papillary-follicular, and 43 were pure follicular carcinomas. There were also 23 anaplastic, 8 medullary, and 3 Hürthle cell carcinomas. These patients were followed up from 3 to 31 years, with a mean range of 10 years. Fifty-three patients with well-differentiated tumors underwent total thyroidectomies, and 179 underwent subtotal thyroidectomies (excluding anaplastic, medullary, and Hürthle cell tumors). Regional lymph node involvement was commonly found but appeared not to affect survival; tumor size and local spread and extent of thyroid gland involvement did affect survival. A small percentage of well-differentiated thyroid tumors do, in time, undergo anaplastic change that leads to metastasis and death. There was no 30-day mortality rate. The late mortality rate was 2% for papillary and 14% for follicular carcinomas. Papillary tumors are becoming more common. Older aged patients and male patients appear to carry poorer prognoses for survival. The total thyroidectomy procedure has not improved survival over subtotal thyroidectomy and carries a higher complication rate. 相似文献
70.
A unilateral supratentorial lesion may cause hypometabolism in the contralateral cerebellar hemisphere (crossed cerebellar diaschisis). We analyzed glucose metabolism, measured by PET-FDG, in the posterior fossa in 67 patients (78 PET studies) with primary unilateral supratentorial brain tumors selected for visually obvious metabolic asymmetry in the cerebellar hemispheres. We found that glucose utilization was 17% lower in the contralateral cerebellar cortex (compared with the ipsilateral one), consistent with the selection criterion, and 19% lower in the ipsilateral pons, wherein lie the first order synapses of the corticopontocerebellar pathway. This finding helps to validate the prevalent view that cerebellar diaschisis is due to interruption of afferent input from the corticopontocerebellar pathway. However, glucose metabolism in the contralateral dentate nucleus was relatively preserved--only 2% less than the ipsilateral dentate. This "dentate sparing" suggests preservation of afferent input to the largest of the deep cerebellar nuclei from the Purkinje cells in the cortex, despite interruption of the major excitatory input to the Purkinje cells. 相似文献