全文获取类型
收费全文 | 2931篇 |
免费 | 200篇 |
国内免费 | 149篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 114篇 |
妇产科学 | 14篇 |
基础医学 | 240篇 |
口腔科学 | 39篇 |
临床医学 | 597篇 |
内科学 | 641篇 |
皮肤病学 | 34篇 |
神经病学 | 416篇 |
特种医学 | 406篇 |
外科学 | 130篇 |
综合类 | 52篇 |
预防医学 | 112篇 |
眼科学 | 31篇 |
药学 | 194篇 |
1篇 | |
肿瘤学 | 252篇 |
出版年
2023年 | 19篇 |
2021年 | 41篇 |
2020年 | 27篇 |
2019年 | 30篇 |
2018年 | 41篇 |
2017年 | 30篇 |
2016年 | 36篇 |
2015年 | 34篇 |
2014年 | 35篇 |
2013年 | 75篇 |
2012年 | 60篇 |
2011年 | 101篇 |
2010年 | 82篇 |
2009年 | 80篇 |
2008年 | 125篇 |
2007年 | 206篇 |
2006年 | 96篇 |
2005年 | 116篇 |
2004年 | 98篇 |
2003年 | 108篇 |
2002年 | 95篇 |
2001年 | 79篇 |
2000年 | 69篇 |
1999年 | 74篇 |
1998年 | 88篇 |
1997年 | 90篇 |
1996年 | 90篇 |
1995年 | 76篇 |
1994年 | 52篇 |
1993年 | 66篇 |
1992年 | 58篇 |
1991年 | 65篇 |
1990年 | 56篇 |
1989年 | 87篇 |
1988年 | 67篇 |
1987年 | 88篇 |
1986年 | 56篇 |
1985年 | 74篇 |
1984年 | 53篇 |
1983年 | 50篇 |
1982年 | 40篇 |
1981年 | 35篇 |
1980年 | 33篇 |
1979年 | 29篇 |
1978年 | 34篇 |
1977年 | 37篇 |
1976年 | 43篇 |
1975年 | 27篇 |
1974年 | 19篇 |
1971年 | 21篇 |
排序方式: 共有3280条查询结果,搜索用时 109 毫秒
131.
alpha-Melanocyte-stimulating hormone protects the allograft in experimental heart transplantation 总被引:7,自引:0,他引:7
Gatti S Colombo G Buffa R Turcatti F Garofalo L Carboni N Ferla L Fassati LR Lipton JM Catania A 《Transplantation》2002,74(12):1678-1684
BACKGROUND: With the increasing need for organ transplantation and the use of "marginal" organs, novel approaches are sought to increase the efficiency and survival of transplanted tissue. We tested the idea that treatment with the anti-inflammatory peptide, alpha-melanocyte-stimulating hormone (alpha-MSH), an endogenous hormone that does not cause marked immunosuppression but does reduce reperfusion injury, may protect allografts and prolong their survival. METHODS: Donor cardiac grafts (Brown Norway) were transplanted heterotopically into the abdomen of recipient (Lewis) rats. Treatments consisted of intraperitoneal injections of Nle DPhe -alpha-MSH (NDP-alpha-MSH) or saline from the time of transplantation until sacrifice or spontaneous rejection. Allografts were removed on day 1, day 4, or at the time of rejection and examined for histopathology and expression of molecules prominent in reperfusion injury, transplant rejection, and apoptosis. RESULTS: NDP-alpha-MSH treatment caused a significant increase in allograft survival and a marked decrease in leukocyte infiltration. Expression of molecules such as endothelin 1, chemokines, and adhesion molecules, which are involved in allograft rejection, was significantly inhibited in NDP-alpha-MSH-treated rats. CONCLUSIONS: The results indicate that protection of the allograft from early injury with alpha-MSH can postpone rejection. Addition of this early protection with the peptide to usual treatment with immunosuppressive agents may, therefore, improve success of organ transplants. 相似文献
132.
Hansen JA Welsh PG Lipton J Cacela D Dailey AD 《Environmental toxicology and chemistry / SETAC》2002,21(1):67-75
Bull trout (Salvelinus confluentus) were recently listed as threatened in the United States under the federal Endangered Species Act. Present and historical habitat of this species includes waterways that have been impacted by metals released from mining and mineral processing activities. We conducted paired bioassays with bull trout and rainbow trout (Oncorhynchus mykiss) to examine the relative sensitivity of each species to Cd and Zn independently and as a mixture. A total of 15 pairs of acute toxicity bioassays were completed to evaluate the effects of different water hardness (30 or 90 mg/L as CaCO3), pH (6.5 or 7.5), and temperature (8 or 12 degrees C) on Cd and Zn toxicity. For both species, the acute toxicity of both Cd and Zn was greater than previously observed in laboratory studies. Bull trout were about twice as tolerant of Cd and about 50% more tolerant of Zn than were rainbow trout. Higher hardness and lower pH water produced lower toxicity and slower rates of toxicity in both species. Elevated temperature significantly increased the sensitivity of bull trout to Zn but decreased the sensitivity (not significantly) of rainbow trout to Zn. At a hardness of 30 mg/L, the toxicity values (i.e., median lethal concentration; 120-h LC50) for both species were lower than the current U.S. national water quality criteria for protection of aquatic life, indicating that current national criteria may not be protective of sensitive salmonids--including the threatened bull trout--in low calcium waters. 相似文献
133.
Temporal and regional expression of NMDA receptor subunit NR3A in the mammalian brain 总被引:4,自引:0,他引:4
Wong HK Liu XB Matos MF Chan SF Pérez-Otaño I Boysen M Cui J Nakanishi N Trimmer JS Jones EG Lipton SA Sucher NJ 《The Journal of comparative neurology》2002,450(4):303-317
NR3A is a developmentally regulated N-methyl-D-aspartate receptor (NMDAR) subunit that was previously known as NMDAR-L or chi-1. Unlike other NMDAR subunits, NR3A inhibits the NMDAR-associated ion channel in a novel manner, and a role in synaptogenesis has been suggested for this subunit. Here, we report a comprehensive study to delineate the temporal and anatomic expression of NR3A protein in the mammalian brain by using a monoclonal anti-NR3A antibody. NR3A protein was found to peak at postnatal day (P) 8, and to decrease gradually from P12 to adulthood in the rat central nervous system. Moreover, NR3A protein was heavily expressed in all areas of the isocortex, portions of the amygdaloid nuclei, and selective cell layers and nuclei of the hippocampus, thalamus, hypothalamus, brainstem, and spinal cord. NR3A protein was also expressed in the cerebellar cortex, whereas only weak signal was detected in the previous in situ studies by using riboprobes. At an ultrastructural level, NR3A was associated specifically with asymmetrical synapses and localized to postsynaptic membranes. This information will facilitate future research on NMDARs by providing clues to possible inclusion of the NR3A subunit in NMDARs in many brain regions. 相似文献
134.
JH CHUNG 《中国药理学与毒理学杂志》2006,20(3)
Arsenic in drinking water is a worldwide health problem that is associated with cardiovascular disease, but the cause is currently unknown. In order to examine whether arsenic affects vasomotor tone in blood vessels, we investigated the effect of arsenic on agonist-induced vasorelaxation and vasoconstriction using the isolated rat aortic rings in in vitro organ bath system. 相似文献
135.
Lipton H 《International journal of emergency mental health》2000,2(3):181-187
The death of a child has the potential to traumatize everyone involved. Child deaths caused by auto crashes, suicides, murders, gun accidents, drowning, fires, natural disasters, sudden illness, and other events trigger painful and profound emotional grief reactions in family members, and, at times, for emergency care providers. What grief reactions do family members experience when their child dies suddenly? What emotional struggles take place with siblings? How do emergency care providers cope with the tragic and painful deaths of children? We are guided by the literature and by our own experiences in pediatric emergency departments in trying to supply answers to the questions posed. 相似文献
136.
A panel of multidisciplinary experts in the field of emergency services was convened by the National Association of Social Workers in 1999 to develop Bereavement Practice Guidelines. Funded by the Department of Health and Human Services, Health Resources and Services Administration, Maternal and Child Health Bureau, this paper discusses the best practices in supporting the family and staff when a child dies suddenly in the Emergency Department. Critical stages ranging from preparation to follow-up are discussed that help to enhance the quality of care provided to the family. A final stage addresses the support needs of staff. 相似文献
137.
Diagnosis and management of cystic duct leakage after laparoscopic cholecystectomy, report of 3 cases 总被引:1,自引:0,他引:1
Li JH Liu HT 《第二军医大学学报》2005,26(10):1143-1143
BACKGROUND: Operative complications after laparoscopic cholecystectomy (LC) vary. Abdominal pain and other symptoms caused by fluid accumulation in the operative area are not uncommon. Cystic duct (CD) leakage is one of the main sources of the fluid. This study was to evaluate the procedures used in the diagnosis and management of CD leakage after LC. METHOD: The clinical materials of 3 patients with CD leakage after LC were studied retrospectively. 相似文献
138.
139.
140.
Frontal lobe dementia with novel tauopathy: sporadic multiple system tauopathy with dementia 总被引:3,自引:0,他引:3
Bigio EH Lipton AM Yen SH Hutton ML Baker M Nacharaju P White CL Davies P Lin W Dickson DW 《Journal of neuropathology and experimental neurology》2001,60(4):328-341
We present a novel tauopathy in a patient with a 10-yr history of progressive frontal lobe dementia and a negative family history. Autopsy revealed mild atrophy of frontal and parietal lobes and severe atrophy of the temporal lobes. There were occasional filamentous tau-positive inclusions, but more interesting were numerous distinctive globular neuronal and glial tau-positive inclusions in both gray and white matter of the neocortex. Affected subcortical regions included substantia nigra, globus pallidus, subthalamic nucleus, and cerebellar dentate nucleus, in a distribution similar to progressive supranuclear palsy (PSP), but without significant accompanying neuronal loss or gliosis. Predominantly straight filaments were detected by electron microscopy (EM), while other inclusions were similar to fingerprint bodies. No twisted ribbons were detected. Immuno-EM studies revealed that only the filamentous inclusions were composed of tau. Immunoblotting of sarkosyl-insoluble tau revealed 2 major bands of 64 and 68 kDa. Blotting analysis after dephosphorylation revealed predominantly 4-repeat tau. Sequence analysis of tau revealed that there were no mutations in either exons 9-13 or the adjacent intronic sequences. The unique cortical tau pathology in this case of sporadic multiple system tauopathy with dementia adds a new pathologic profile to the spectrum of tauopathies. 相似文献