全文获取类型
收费全文 | 6975篇 |
免费 | 674篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 220篇 |
妇产科学 | 146篇 |
基础医学 | 854篇 |
口腔科学 | 210篇 |
临床医学 | 792篇 |
内科学 | 1450篇 |
皮肤病学 | 113篇 |
神经病学 | 568篇 |
特种医学 | 247篇 |
外科学 | 699篇 |
综合类 | 163篇 |
一般理论 | 4篇 |
预防医学 | 820篇 |
眼科学 | 178篇 |
药学 | 691篇 |
中国医学 | 5篇 |
肿瘤学 | 497篇 |
出版年
2022年 | 38篇 |
2021年 | 126篇 |
2020年 | 72篇 |
2019年 | 102篇 |
2018年 | 107篇 |
2017年 | 75篇 |
2016年 | 89篇 |
2015年 | 135篇 |
2014年 | 167篇 |
2013年 | 236篇 |
2012年 | 310篇 |
2011年 | 296篇 |
2010年 | 201篇 |
2009年 | 167篇 |
2008年 | 313篇 |
2007年 | 335篇 |
2006年 | 328篇 |
2005年 | 337篇 |
2004年 | 333篇 |
2003年 | 290篇 |
2002年 | 289篇 |
2001年 | 271篇 |
2000年 | 249篇 |
1999年 | 209篇 |
1998年 | 123篇 |
1997年 | 119篇 |
1996年 | 103篇 |
1995年 | 84篇 |
1994年 | 74篇 |
1993年 | 81篇 |
1992年 | 162篇 |
1991年 | 158篇 |
1990年 | 134篇 |
1989年 | 139篇 |
1988年 | 120篇 |
1987年 | 120篇 |
1986年 | 109篇 |
1985年 | 116篇 |
1984年 | 86篇 |
1983年 | 86篇 |
1982年 | 62篇 |
1981年 | 59篇 |
1980年 | 37篇 |
1979年 | 53篇 |
1978年 | 58篇 |
1976年 | 43篇 |
1975年 | 37篇 |
1974年 | 38篇 |
1973年 | 36篇 |
1972年 | 37篇 |
排序方式: 共有7685条查询结果,搜索用时 13 毫秒
21.
22.
Metronidazole susceptibility testing for Helicobacter pylori: comparison of disk, broth, and agar dilution methods and their clinical relevance. 总被引:6,自引:2,他引:4 下载免费PDF全文
A J DeCross B J Marshall R W McCallum S R Hoffman L J Barrett R L Guerrant 《Journal of clinical microbiology》1993,31(8):1971-1974
Since the methods for metronidazole susceptibility testing of Helicobacter pylori have not been standardized or validated, we compared three methods that are used to test the metronidazole susceptibilities of 25 isolates of H. pylori. Specifically, we examined the methods of Steer's replicator agar dilution, tube broth microdilution, and modified Kirby-Bauer disk diffusion. The metronidazole disk zone sizes obtained by the disk diffusion method correlated well (r = 0.74) with the MICs obtained by the agar dilution method. Afterward, the disk diffusion method was used to characterize the metronidazole susceptibilities of 44 isolates of H. pylori. Dual therapy (bismuth and metronidazole) proved to be highly effective against metronidazole-susceptible strains (81.6% eradication rate) but fared poorly against resistant strains (16.7% eradication rate; P < 0.01). Using agar dilution testing, we validated the modified Kirby-Bauer disk diffusion method for metronidazole susceptibility testing of H. pylori and conclude that it is practical, accurate, and clinically applicable. 相似文献
23.
B. Vaidya P. E. Harris P. Barrett P. Kendall-Taylor 《Postgraduate medical journal》1997,73(866):817-819
We report a case of Riedel''s thyroiditis presenting with a systemic illness, life-threatening stridor and a stony hard goitre. Diagnosis was confirmed by open thyroid biopsy. Treatment with corticosteroid resulted in a dramatic improvement. A possible autoimmune mechanism in the pathogenesis of Riedel''s thyroiditis is discussed. 相似文献
24.
Joyce Toral William Hu Donald Critchett Andrew J. Solomon James E. Barrett Patricia T. Sokol M. Reza Ziai 《The Journal of pharmacy and pharmacology》1995,47(7):618-622
The 5-HT3-receptor antagonist, ondansetron, has been shown to have positive effects in selected in-vivo models of memory impairment and anxiety. The exact mechanisms underlying such bioactivities are unknown. In the present work, an 86Rb efflux bioassay was used to show that ondansetron has a unique ability to block voltage-gated potassium channels in TE671 human neuroblastoma cells. This intrinsic potassium-channel-blocking (KCB) property is relatively weak (IC50 20 (M), but is not shared by other 5-HT3-receptor ligands including zatosetron, MDL 72222, LY 278, 584, zacopride, 1-phenylbiguanide, and ICS 205–930 (tropisetron). Pre-incubation of the target neuroblastoma cells with several 5-HT-receptor ligands including 5-hydroxytryptamine, 8-OH-DPAT, ketanserin, 2-methyl-5-HT, as well as a number of potent 5-HT3 agonists and antagonists and two selective neurotoxins, failed to abolish the KCB action of ondansetron. A preliminary structure-activity relationship analysis indicates that the KCB activity of ondansetron is almost entirely attributable to its structural nucleus, 2,3-dihyro-9-methyl-4(lH)-carbazolone. It is hypothesized that the KCB action of ondansetron is mediated through receptors other than 5-HT3 receptors. The KCB activity of ondansetron may be a significant factor in the in-vivo cognition-enhancing activities of this compound, conceivably due to depolarization of the hippocampal synaptic membranes and a consequent augmentation of neurotransmission. 相似文献
25.
26.
Infection by the Human T-Lymphotropic Virus Type III (HTLV-III) may lead to the devastating and ultimately fatal disease, acquired immunodeficiency syndrome (AIDS). As the virus is transmitted in similar ways to the hepatitis B virus, concern has developed within the dental profession regarding the possibility of clinicians acquiring AIDS through treatment of infected patients. This paper aims to place the significance of HTLV-III infection to dental practice in perspective. 相似文献
27.
Neurites of cultured septal neurons were transected with a laser under sterile conditions, and the subsequent membrane resealing was assayed using a dye exclusion method. In agreement with findings in other preparations, Ca2+ enhanced resealing: in normal culture medium the percentage of lesioned neurons that resealed within 20-30 min after transection increased with increasing bath [Ca2+] over the range 10(-7) to 2 x 10(-3) M; about 75% of cells resealed in 2 mM Ca2+. Mn2+ and Sr2+ also enhanced resealing, but Mg2+ inhibited it. The percentage of resealing neurons was sensitive to agents known to alter the stability of cytoskeletal components. Agents that tend to disassemble microtubules and/or neurofilaments (e.g., colchicine, low-ionic-strength media) strongly promoted resealing, whereas treatments that tend to stabilize microtubules (taxol, Mg2+) inhibited resealing. Addition of exogenous proteases (papain, trypsin, or dispase) enhanced resealing, whereas inhibitors of cysteine proteases (including a specific inhibitor of calpain, a Ca-activated neutral protease) strongly inhibited resealing. Calmodulin inhibitors inhibited resealing, consistent with reports that calmodulin facilitates calpain-mediated proteolysis of fodrin, a component of the cortical cytoskeleton. Based on these results, we hypothesize that one of the major mechanisms involved in resealing is activation of endogenous proteases by Ca2+ entry into the injured neurite. The resulting changes in the cellular cytoskeleton might promote fusion and resealing of the cut ends of the plasma membrane by enhancing membrane mobility and/or by removing structures that normally prevent membrane-membrane contact. 相似文献
28.
C R Pinkerton J Groot-Loonen A Barrett S T Meller D Tait S Ashley T J McElwain 《British journal of cancer》1991,64(2):381-385
Forty-three children with malignant soft tissue sarcomas (IRS Groups II-IV) were treated with rapid dose delivery chemotherapy protocol comprising six courses of vincristine, adriamycin and cyclophosphamide, given in most cases within 8 weeks (Rapid VAC). This was followed in 36 patients by high dose melphalan with autologous bone marrow rescue. Twenty-six patients also received irradiation to the site of primary tumour. The Rapid VAC regimen was well tolerated and largely administered as an out-patient. There was one toxic death which occurred 2 months after high dose melphalan due to a combination of infection and possible anthracycline cardiomyopathy. Stages were, (Intergroup Rhabdomyosarcoma Study (IRS) system) Group, Group II--four patients. Group III--27 patients and Group IV--12 patients; International Society of Paediatric Oncology (SIOP) staging, Stage I--11, Stage II--13, Stage III--7, Stage IV--12. Actuarial survival at 5 years for all stages is 57% and event free survival 44%. For patients with non-metastatic diseases, 62% and 53% respectively. This treatment strategy utilises the philosophy of rapid drug delivery with high dose consolidation and enables all chemotherapy to be finished within a 4 month period. In general, a conservative approach was applied to both radiation and surgery to minimise late sequelae related to these treatment modalities. Although the small number of high risk patients in this study limits conclusions regarding efficacy in these subgroups the overall results with this regimen appear to be comparable to that with other approaches. 相似文献
29.
A technique for undiverting a colonic conduit of limited capacity and with short ureters is described. The colonic segment of the conduit and an additional segment of small bowel are patched together to form a low pressure cystoplasty of large capacity. This technique incorporates 3 principles that are believed to be important in reconstructing any type of cystoplasty: large capacity, increase in diameter and disruption of the strong circular muscle layer of the bowel by detubularization. 相似文献
30.
Detection of frequent allelic loss on proximal chromosome 17q in sporadic breast carcinoma using microsatellite length polymorphisms. 总被引:20,自引:0,他引:20
P A Futreal P S?derkvist J R Marks J D Iglehart C Cochran J C Barrett R W Wiseman 《Cancer research》1992,52(9):2624-2627
Analyses of losses of heterozygosity and linkage studies have implicated a gene(s) on chromosome 17q in the genesis of sporadic and early-onset familial breast carcinomas, respectively. To define the critical region of 17q, we examined DNAs from a series of 20 sporadic breast carcinomas and corresponding blood samples for allelic losses of chromosome 17q using microsatellite length polymorphisms. With these highly informative markers (average heterozygosity, 0.73), we observed frequent deletions of 17q at several loci. We found that D17S250 was deleted in 50% (7 of 14), THRA1 in 79% (11 of 14), D17S579 in 59% (11 of 19), NME1 in 29% (5 of 17), MPO in 36% (4 of 11), and GH in 25% (4 of 16) in the tumor set examined. A common region of deletion was found that was flanked by D17S250 to D15S579. These markers have recently been localized to a 6-cM interval of proximal chromosome 17q in bands 17q11.2-q21 and map within the region of the early-onset familial breast cancer locus, implying that the same gene or genes may be involved in both sporadic and familial breast tumors. Thyroid hormone receptor alpha and retinoic acid receptor alpha are two potential candidate genes in this region. 相似文献