全文获取类型
收费全文 | 179742篇 |
免费 | 15658篇 |
国内免费 | 5560篇 |
专业分类
耳鼻咽喉 | 1074篇 |
儿科学 | 4532篇 |
妇产科学 | 2428篇 |
基础医学 | 28770篇 |
口腔科学 | 3230篇 |
临床医学 | 12662篇 |
内科学 | 26217篇 |
皮肤病学 | 2441篇 |
神经病学 | 27507篇 |
特种医学 | 6490篇 |
外国民族医学 | 34篇 |
外科学 | 15384篇 |
综合类 | 17684篇 |
现状与发展 | 18篇 |
预防医学 | 8200篇 |
眼科学 | 1472篇 |
药学 | 23045篇 |
48篇 | |
中国医学 | 5749篇 |
肿瘤学 | 13975篇 |
出版年
2023年 | 2850篇 |
2022年 | 6114篇 |
2021年 | 7492篇 |
2020年 | 6357篇 |
2019年 | 7504篇 |
2018年 | 7165篇 |
2017年 | 6597篇 |
2016年 | 6032篇 |
2015年 | 6637篇 |
2014年 | 10010篇 |
2013年 | 10995篇 |
2012年 | 8966篇 |
2011年 | 10267篇 |
2010年 | 8457篇 |
2009年 | 8371篇 |
2008年 | 8362篇 |
2007年 | 7510篇 |
2006年 | 6767篇 |
2005年 | 6057篇 |
2004年 | 5038篇 |
2003年 | 4709篇 |
2002年 | 3574篇 |
2001年 | 3121篇 |
2000年 | 2612篇 |
1999年 | 2441篇 |
1998年 | 2222篇 |
1997年 | 2237篇 |
1996年 | 1952篇 |
1995年 | 1738篇 |
1994年 | 1645篇 |
1993年 | 1425篇 |
1992年 | 1207篇 |
1991年 | 1069篇 |
1990年 | 923篇 |
1989年 | 830篇 |
1988年 | 809篇 |
1987年 | 745篇 |
1986年 | 882篇 |
1985年 | 2061篇 |
1984年 | 2790篇 |
1983年 | 1861篇 |
1982年 | 2032篇 |
1981年 | 1880篇 |
1980年 | 1624篇 |
1979年 | 1341篇 |
1978年 | 1091篇 |
1977年 | 922篇 |
1976年 | 1033篇 |
1975年 | 698篇 |
1973年 | 636篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
BACKGROUND: Studies have shown that alcoholics have smaller brain volumes than non-alcoholic cohorts, but an effect of family history (FH) of heavy drinking on brain volume has not been demonstrated. We examined the relationship between an FH of heavy drinking and both brain shrinkage as measured by the ratio of brain volumes to intracranial volume (ICV) as well as maximal brain growth as measured by ICV in early-onset and late-onset alcoholics. METHODS: With T1-weighted resonance imaging, we measured ICV, brain volume, and white and gray matter volume in adult treatment-seeking late-onset and early-onset alcoholics with either a positive or a negative FH of heavy alcohol use, and in healthy control subjects. We also calculated brain shrinkage using a ratio of soft tissue volumes to ICV. RESULTS: The FH positive alcoholic patients had significantly smaller ICVs than FH negative patients, suggesting smaller premorbid brain growth. Brain shrinkage did not correlate with FH. Late-onset alcoholics showed a greater difference in ICV between FH positive and FH negative patients than early-onset alcoholics. Late-onset FH positive patients also had significantly lower IQ scores than late-onset FH negative patients, and IQ scores were correlated with ICV. CONCLUSIONS: These data provide evidence that parental alcohol use might increase risk for alcoholism in offspring in part by a genetic and/or environmental effect that might be related to reduced brain growth. 相似文献
62.
血管内皮生长因子在高原脑水肿形成中作用的实验研究 总被引:4,自引:0,他引:4
目的:探讨血管内皮生长因子(VEGF)在高原脑水肿形成中的作用。方法:建立大鼠模拟高原模型,应用脑干湿重比率法定量脑水肿情况、应用荧光素钠透过率测定BBB通透性、应用实时荧光定量RT-PCR法检测脑组织VEGF mRNA含量以及应用蛋白印迹法半定量脑组织VEGF含量。结果:大鼠在高原24 h后脑组织含水率明显增高(P<0.05),荧光素钠透过率显著增加(P<0.01);VEGF mRNA转录及其表达显著增高(P<0.001)。结论:VEGF表达在高原脑水肿形成中起重要作用。 相似文献
63.
Intractable tinnitus can lead to serious consequences. Study evidence indicates that the central nervous system is involved in generation and maintenance of chronic tinnitus and that tinnitus and other neurologic symptoms such as chronic pain may share similar mechanisms. Brain ablation and stimulation are used to treat chronic pain with success. Recent studies showed that ablation and stimulation in non-auditory areas resulted in tinnitus improvement. Deep brain stimulation (DBS) may be an alternative treatment for intractable tinnitus and deserves further study. 相似文献
64.
65.
Giorgio Ciprandi Mara De Amici Simone Negrini Gianluigi Marseglia Maria Angela Tosca 《International immunopharmacology》2009,9(10):1247-1249
Two new T cell subsets may be involved in allergic rhinitis (AR) pathogenesis: Th17 and T regulatory cells, mainly producing IL-17 and TGF-β respectively. Successful Sublingual Immunotherapy (SLIT) induces relevant immunological changes, thus the aim of this study was to evaluate serum IL-17 and TGF-β levels in AR patients treated with SLIT for 2 years. Patients' blood samples were collected before initiating SLIT (baseline), three months after the end of the first pre-seasonal SLIT course, and at the end of the second pre-seasonal course. IL-17 was detectable only in the most severe allergic patients. SLIT significantly induced an increase in serum TGF-β levels. There was moreover a significant relationship between TGF-β and symptom severity and drug use at the end of the study. Therefore, this study provides clinically relevant evidence that two pre-seasonal SLIT courses may significantly affect serum TGF-β levels. 相似文献
66.
67.
益气复智颗粒对多发脑梗死性痴呆模型大鼠脑组织细胞凋亡的影响 总被引:1,自引:0,他引:1
目的 观察益气复智颗粒对多发脑梗死性痴呆模型大鼠脑皮质形态学、细胞凋亡的影响。方法 采用颈内动脉注射血栓的方法,复制多发梗死性痴呆大鼠模型,观察益气复智颗粒12.42g/kg分别于手术前、手术前后、手术后灌胃对实验动物脑皮质形态学、细胞凋亡的影响。结果 益气复智颗粒能使脑缺血后脑内神经细胞凋亡数目下降。结论 益气复智颗粒具有较好的保护脑神经元,阻断脑缺血致神经细胞死亡病理过程的作用。 相似文献
68.
Gregory J. Pomper Rita A. Joseph Erica L. Hartmann Michael S. Rohr Patricia L. Adams Robert J. Stratta 《American journal of transplantation》2005,5(10):2586-2589
Massive immune hemolysis due to passenger lymphocyte-derived anti-D has not been reported in renal transplantation. A 50-year-old (B-positive) male received a dual deceased-donor kidney transplant (B-negative) for diabetic renal failure. Two weeks post-transplant, the patient developed severe hemolytic anemia. The donor anti-D titer was 1:8. The recipient anti-D titer (zero pre-transplant) increased from 1:4 to 1:16 over 4 days. Rapid hemolysis caused severe anemia, minimum Hb = 4.2 g/dL, while selectively lysing the patient's autologous red cells during this time. The hemolytic anemia did not impair the allografts and subsided without monoclonal B-cell pharmacotherapy or apheresis. The anti-D titer decreased to barely detectable levels at four months and had cleared when checked 2 years post-transplant. Transfusion support subsided after two months. If complications of anemia can be avoided, the deleterious effects of hemolysis may be well tolerated by renal allografts using antigen negative transfusion alone. 相似文献
69.
螺旋CT三维重建成像在先天性高肩胛症手术方式选择中的作用 总被引:4,自引:2,他引:2
[目的]探讨螺旋CT三维重建技术在先天性高肩胛症分度和手术方式选择中的作用。[方法]22例先天性高肩胛症术前应用螺旋CT对病变部位进行扫描并三维重建,测量以肩胛骨肩胛冈内侧缘为参照点,两侧肩胛骨高度差。根据测量结果依据Cavendish分度将其分类,并根据三维重建成像选择不同的矫形手术术式。[结果]本组22例病人,随访2—4年,外观及功能均有不同程度的改善,未出现神经、血管和椎体等的损伤。[结论]根据螺旋CT扫描和三维重建检查结果,术前即可直观的明确先天性高肩胛症的病变程度,相互关系,伴发畸形,患侧肩胛骨与正常对侧肩胛骨的外观差异等,便于手术操作方案的制定,避免了手术操作的盲目性,减少医源性并发症的发生。 相似文献
70.
Terry Joe Sprinkle Julia F. Agee Russell B. Tippins C. Richard Chamberlain Guy B. Faguet George H. DeVries 《Brain research》1987,426(2):349-357
Monoclonal antibodies against human and bovine 2′:3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) were generated by fusing FOX-NY myeloma cells with spleen cells from RBF/Dn mice previously immunized with the purified brain antigens. The enzyme isolated from bovine brain was quite basic, with an isoelectric point of 9.71 and both the bovine and human enzymes consisted of a closely spaced doublet at approximately 44 and 46 kDa on SDS-PAGE. Six monoclonals were identified as strongly recognizing the enzyme on both ELISA plates and on immunoblots of whole brain protein. Four monoclonals very weakly cross-reacted with guinea pig myelin basic protein. In contrast with two previous reports, some of our monoclonal antibodies did immunostain 2 or 3 protein bands in peripheral nerve, two bands closely corresponding to those immunostained in central nervous system (CNS) myelin, the Wolfgram protein fraction and in acetone powders of whole brain. Each of the 6 monoclonals reacting strongly on immunoblots recognized the enzyme in from 2 to 5 of the species examined (human, bovine, rat, mouse and rabbit). In addition, all 6 monoclonals that immunostained the enzyme in whole brain, myelin and Wolfgram protein immunoblots recognized both CNP1 (44 kDa) and CNP2 (46 kDa). The two closely spaced protein bands observed on SDS-PAGE and previously stained on immunoblots of CNS CNPase using polyvalent rabbit anti-bovine CNPase antisera, and now different monoclonal antibodies, appear to be immunologically related and to contain highly conserved sequences. 相似文献