全文获取类型
收费全文 | 188387篇 |
免费 | 1625篇 |
国内免费 | 121篇 |
专业分类
耳鼻咽喉 | 1308篇 |
儿科学 | 6890篇 |
妇产科学 | 3173篇 |
基础医学 | 18539篇 |
口腔科学 | 1887篇 |
临床医学 | 13536篇 |
内科学 | 33237篇 |
皮肤病学 | 1180篇 |
神经病学 | 17475篇 |
特种医学 | 9470篇 |
外科学 | 30620篇 |
综合类 | 2360篇 |
一般理论 | 2篇 |
预防医学 | 18633篇 |
眼科学 | 3081篇 |
药学 | 10596篇 |
中国医学 | 810篇 |
肿瘤学 | 17336篇 |
出版年
2023年 | 101篇 |
2022年 | 323篇 |
2021年 | 518篇 |
2020年 | 283篇 |
2019年 | 372篇 |
2018年 | 22271篇 |
2017年 | 17631篇 |
2016年 | 19910篇 |
2015年 | 1521篇 |
2014年 | 1515篇 |
2013年 | 1542篇 |
2012年 | 8164篇 |
2011年 | 22055篇 |
2010年 | 19435篇 |
2009年 | 12054篇 |
2008年 | 20198篇 |
2007年 | 22425篇 |
2006年 | 1192篇 |
2005年 | 2752篇 |
2004年 | 3842篇 |
2003年 | 4705篇 |
2002年 | 2828篇 |
2001年 | 561篇 |
2000年 | 689篇 |
1999年 | 368篇 |
1998年 | 262篇 |
1997年 | 256篇 |
1996年 | 122篇 |
1995年 | 150篇 |
1994年 | 120篇 |
1993年 | 76篇 |
1992年 | 118篇 |
1991年 | 150篇 |
1990年 | 203篇 |
1989年 | 142篇 |
1988年 | 114篇 |
1987年 | 85篇 |
1986年 | 71篇 |
1985年 | 73篇 |
1984年 | 48篇 |
1983年 | 53篇 |
1982年 | 39篇 |
1980年 | 58篇 |
1979年 | 39篇 |
1978年 | 52篇 |
1975年 | 35篇 |
1974年 | 46篇 |
1938年 | 60篇 |
1932年 | 56篇 |
1930年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Transneuronal degeneration of thalamic neurons following partial deafferentation was studied using [3H]thymidine autoradiography. Timed-pregnant female Sprague-Dawley rats received systemic injections of [3H]thymidine on embryonic day (E) 13, 14 and/or 15. On the day of birth, pups were anesthetized by hypothermia and subjected to unilateral enucleation, unilateral removal of the inferior colliculus or sham lesion. Animals were sacrificed on postnatal day 10 or 30 and the brains processed for autoradiography. Material from sham-lesioned animals demonstrates that neurons destined for the dorsal lateral geniculate nucleus (LGd) undergo final mitoses on E13, 14 and 15. Neurons in the ventral medial geniculate nucleus (MGv) undergo final mitoses on E13 and 14. Thirty days following neonatal unilateral eye removal, the contralateral LGd displays a loss of approximately 30-35% of [3H]thymidine labeled neurons. Neonatal unilateral removal of the inferior colliculus results in a loss of approximately 30-40% of labeled neurons in MGv. For both LGd and MGv, shorter survival times reveal less severe cell loss. Late generated (E15) LGd neurons show less severe loss following enucleation than do earlier generated neurons. These results document the degree of cell loss in sensory thalamic nuclei following deafferentation and demonstrate that [3H]thymidine autoradiography provides a useful quantitative method for assessing anterograde transneuronal cell loss in targeted populations of neurons in the developing central nervous system. 相似文献
12.
13.
14.
Interaction between free radicals and excitatory amino acids in the formation of ischemic brain edema in rats 总被引:6,自引:0,他引:6
Both oxygen free radicals and excitatory amino acids have been implicated as important cellular toxins in ischemic brain. Recent in vitro studies suggest that there may be a mutual interaction between these two mediators. We explored the relation between oxygen free radicals and excitatory amino acids in the development of ischemic brain edema in vivo. Male Sprague-Dawley rats were treated with the free radical scavenger dimethylthiourea 1 hour before ischemia or with the excitotoxin antagonist MK-801 30 minutes before ischemia produced by occlusion of the middle cerebral artery. Groups of seven or eight animals were treated with vehicle, low-dose (375 mg/kg) dimethylthiourea, high-dose (750 mg/kg) dimethylthiourea, low-dose (0.5 mg/kg) MK-801, high-dose (2.0 mg/kg) MK-801, or both high-dose dimethylthiourea and low-dose MK-801. After 4 hours of ischemia, brain water content was determined. In eight vehicle-treated controls, mean +/- SEM water content of tissue in the center of the ischemic zone was 83.29 +/- 0.18%. A significant reduction of brain edema was observed in all drug-treated groups: for example, 50.2% (p less than 0.001) in the high-dose dimethylthiourea group, 53.7% (p less than 0.001) in the low-dose MK-801 group, and 66.4% (p less than 0.001) in the combined dimethylthiourea and MK-801 group. Combined treatment with dimethylthiourea and MK-801 provided no significant additive effect over that resulting from treatment with MK-801 alone.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
15.
16.
Paul Hochstein Ulrich Glatzel Thomas Schmickal Andreas Wentzensen 《Trauma und Berufskrankheit》2002,4(2):s110-s114
The treatment of deep cartilage defects in load-bearing joints is a problem that still has no satisfactory solution. Full-thickness defects of the articular cartilage rarely heal spontaneously, usually leaving damage that can lead to early arthrosis. Techniques currently available for the treatment of chondral defects include abrasion, drilling, micro-fracturing, transplantation of tissue autografts and allografts, and cell transplantation. Osteochondral autograft transplantation is currently the only surgical cartilage repair technique known to lead to the formation of genuine hyaline articular cartilage and its retention at least in the medium term. The Draenert method, in which a water-cooled diamond bone-cutting system is used, is an effective procedure for resurfacing the joints affected by localised cartilaginous defects, even when there is also severe bone loss. Donor-side morbidity can be kept to a minimum by filling the defect caused by harvesting with a press-fit cylinder of cancellous bone covered with periosteum for protection. 相似文献
17.
J. Bryan Page 《Journal of urban health》2005,82(3):iii35-iii43
Contemporary discourse contains numerous examples of use of the concept of culture by social and behavioral scientists. Simple reification, where the speaker makes culture into a thing capable of action exemplifies one usage in public discourse. Some quantitative social scientists attempt to characterize people’s cultural identities by means of a single categorical variable, which often “lumps” people into categories such as “Hispanic” or “Black” that in fact have numerous culturally bounded subcategories. Approaches that emphasize cultural process are preferable to those who attempt to categorize; more complex measures of acculturation help investigators to make convincing analyses of circumstances in which health disparities occur. Examples in which investigators make appropriate use of cultural characterizations demonstrate their utility in investigating health disparities in Haitian American women, injecting and noninjecting drug users, Hispanic youth, and adult Hispanics at risk of HIV infection. Focus on culture in the study of health disparities can identify entanglements between structural factors such as poverty and lack of education and cultural factors such as beliefs about health. Qualitative methods coupled with quantitative methods have great potential to improve investigators’ grasp of cultural nuance while capturing the distribution of qualitatively derived behaviors. 相似文献
18.
19.
20.
Pilar Nicolás 《Hereditary cancer in clinical practice》2007,5(3):144-152
The specific characteristics of genetic data lead to ethical-legal conflicts in the framework of genetic diagnosis. Several international organisations, including UNESCO and the Council of Europe, have enacted rules referring to the use of genetic information. This paper discusses possible legal and ethical criteria that could be used in genetic testing. 相似文献