全文获取类型
收费全文 | 123829篇 |
免费 | 8129篇 |
国内免费 | 536篇 |
专业分类
耳鼻咽喉 | 1317篇 |
儿科学 | 3664篇 |
妇产科学 | 2068篇 |
基础医学 | 16489篇 |
口腔科学 | 2212篇 |
临床医学 | 12230篇 |
内科学 | 26255篇 |
皮肤病学 | 1484篇 |
神经病学 | 11986篇 |
特种医学 | 3817篇 |
外国民族医学 | 1篇 |
外科学 | 17792篇 |
综合类 | 1671篇 |
现状与发展 | 1篇 |
一般理论 | 156篇 |
预防医学 | 10785篇 |
眼科学 | 3325篇 |
药学 | 8778篇 |
1篇 | |
中国医学 | 280篇 |
肿瘤学 | 8182篇 |
出版年
2023年 | 614篇 |
2022年 | 1070篇 |
2021年 | 2373篇 |
2020年 | 1414篇 |
2019年 | 2411篇 |
2018年 | 2814篇 |
2017年 | 2048篇 |
2016年 | 2388篇 |
2015年 | 2752篇 |
2014年 | 3976篇 |
2013年 | 5577篇 |
2012年 | 8501篇 |
2011年 | 9131篇 |
2010年 | 4987篇 |
2009年 | 4655篇 |
2008年 | 8059篇 |
2007年 | 8549篇 |
2006年 | 8094篇 |
2005年 | 8147篇 |
2004年 | 7688篇 |
2003年 | 7089篇 |
2002年 | 6830篇 |
2001年 | 1212篇 |
2000年 | 908篇 |
1999年 | 1243篇 |
1998年 | 1454篇 |
1997年 | 1232篇 |
1996年 | 954篇 |
1995年 | 947篇 |
1994年 | 806篇 |
1993年 | 791篇 |
1992年 | 677篇 |
1991年 | 616篇 |
1990年 | 549篇 |
1989年 | 508篇 |
1988年 | 514篇 |
1987年 | 496篇 |
1986年 | 424篇 |
1985年 | 506篇 |
1984年 | 570篇 |
1983年 | 527篇 |
1982年 | 700篇 |
1981年 | 613篇 |
1980年 | 538篇 |
1979年 | 377篇 |
1978年 | 348篇 |
1977年 | 349篇 |
1976年 | 294篇 |
1975年 | 273篇 |
1974年 | 282篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Diarrhea is common after liver transplantation (LT). The true incidence of diarrhea in liver transplant recipients is unknown but possibly ranges from 10% to 43% based on a few published studies in other solid organ and bone marrow transplantation. Infectious etiologies, including cytomegalovirus (CMV), Clostridium difficile, and occasional atypical intestinal infections, are the most common causes. Diarrhea is also a frequent side effect of immunosuppressive medications. To variable extents, mycophenolate mofetil (MMF), cyclosporine A (CSA), tacrolimus, and sirolimus are all known to be associated with diarrhea. Rarely, graft-versus-host disease (GVHD), lymphoproliferative disorder, de novo inflammatory bowel disease (IBD), or colon cancer may present as diarrhea. Flare-up of preexisting IBD is also not uncommon after LT. However, the cause of acute diarrhea remains unidentified in 1 of 3 patients. This review summarizes the literature and provides recommendations on the management of acute diarrhea after LT. Although our focus is on LT, the etiology and management recommendations apply to most transplant recipients. 相似文献
73.
Paul R Gard Pauline Daw Zhila Sayyad Mashhour Paula Tran 《Journal of the renin-angiotensin-aldosterone system》2007,8(3):133-138
INTRODUCTION: Angiotensin (Ang) IV enhances learning and memory in rats but there are strain differences in its effects in mice. Oxytocin (OT) also influences learning and memory in rats and mice and, in the light of the proposed effects of Ang IV on oxytocinase, the hypothesis that the effects of Ang IV on cognition in mice involve OT was tested. MATERIALS AND METHODS: The effects of Ang IV and OT, alone and combined, were determined in rat isolated uterine smooth muscle and in object recognition and forced swim tests in BKW mice. RESULTS: Ang potentiated the contractile effects of OT in the uterus. Neither peptide had any effect on object recognition nor locomotor activity. Ang IV had no effect in the forced swim test but abolished the effects of OT. CONCLUSIONS: Ang IV influences the actions of OT in vitro and in vivo, possibly by inhibition of oxytocinase, but the lack of effect of Ang IV on object recognition in BKW mice is unlikely to be a consequence of a deficiency endogenous OT. Unlike OT, Ang IV alone has no effect on learned helplessness in the forced swim test, an effect often used to predict potential antidepressant efficacy in humans. 相似文献
74.
75.
76.
The use of a new hydrophilic polymer, Kollicoat IR, in the formulation of solid dispersions of Itraconazole. 总被引:1,自引:0,他引:1
Sandrien Janssens Hector Novoa de Armas Jean Paul Remon Guy Van den Mooter 《European journal of pharmaceutical sciences》2007,30(3-4):288-294
Kollicoat IR, a new pharmaceutical excipient developed as a coating polymer for instant release tablets, was evaluated as a carrier in solid dispersions of Itraconazole. The solid dispersions were prepared by hot stage extrusion. Modulated temperature differential scanning calorimetry and X-ray powder diffraction were used to evaluate the miscibility of the drug and the carrier. The pharmaceutical performance was evaluated by dissolution experiments, performed in simulated gastric fluid without pepsin (SGF(sp)). In the X-ray diffractograms no Itraconazole peaks were visible; the polymer on the other hand appeared to be semi-crystalline. Moreover, its crystallinity increased during the extrusion process due to exposure to heat and shear forces. Modulated temperature differential scanning calorimetry analysis showed that the drug and the polymer formed a two phase system. Separate clusters of glassy Itraconazole were present for drug loads of 40% or higher, indicating further phase separation. Dissolution measurements demonstrated a significantly increased dissolution rate for the solid dispersions compared to physical mixtures. Interestingly the physical mixture made up of glassy Itraconazole and Kollicoat IR (20/80, w/w) showed a dissolution rate and maximum that was much higher than that of the physical mixture made up of crystalline Itraconazole and that of pure glassy Itraconazole. The results of this study show that Kollicoat IR is a promising excipient for the formulation of solid dispersions of Itraconazole prepared by hot stage extrusion. 相似文献
77.
78.
Paul S. Gaynon MD 《Current hematologic malignancy reports》2007,2(3):193-201
Acute lymphoblastic leukemia (ALL) is the most common cancer in children. Careful building upon past clinical trials and thoughtful
application of our limited knowledge of pharmacology have provided steady improvement in outcome for newly diagnosed patients.
Precise identification of the many patients who are unlikely to relapse with current effective regimens is required to avoid
the morbidity of further intensification of therapy. Progress is sorely lacking for relapsed patients. Most patients who relapse
die. Gene expression arrays and comparative genomic hybridization have further extended our appreciation of the known immunophenotypic
and genetic diversity of childhood ALL. Insight into the molecular mechanisms of treatment failure may provide guidance for
future efforts. 相似文献
79.
E.Paul Kirk MB BS J. Santa MD T. Heckler MBA M. Collins MD 《American journal of obstetrics and gynecology》1998,178(6):1222-1228
OBJECTIVE: Our purpose was to assess whether legislative action influenced the role of obstetrician-gynecologists as primary care physicians. STUDY DESIGN: An observational study was performed on the basis of a questionnaire sent to 410 obstetrician-gynecologists and 27 medical directors of managed-care organizations. RESULTS: Of 67% of obstetrician-gynecologists and 96% of medical directors who responded, there was agreement as to the content of primary care, but a minority (38%) of obstetrician-gynecologists identified themselves as primary care providers. A minority of medical directors (35%) felt that obstetrician-gynecologists should serve in that role. Both obstetrician-gynecologists and medical directors felt that legislation had little impact. CONCLUSION: The reticence of obstetrician-gynecologists to assume a major role in primary care appears to be the result of an uneasiness with accepting a more comprehensive role in patient management and gatekeeping. They appear comfortable with the more traditional roles but feel that training and experience has not prepared them well for the management of more complex medical problems. (Am J Obstet Gynecol 1998;178:1222-8.) 相似文献
80.
David S. Park Paul Manowitz Stanley Stein Ronald D. Poretz 《Alcoholism, clinical and experimental research》1996,20(2):234-239
Several electrophoretic forms of human platelet arylsulfatase A (ASA), including variant type IIIa and normal type IVa , have been identified by nondenaturing polyacrylamide gel electrophoresis. An alcoholic population that we have analyzed is enriched in variant type IIIa compared with nonalcoholic psychiatric and normal controls. Individuals with the IIIa enzyme possess greatly reduced levels of ASA activity. To understand further the structural basis for the differences and their potential biological consequences, the nature of the ASA variant expressed by fibroblasts from different individuals was explored. The electrophoretic patterns of fibroblast ASA from the IIIa and IVa individuals differ in degree of phosphorylation. Furthermore, fibroblast ASA from IIIa individuals lacks an N -linked glycan found in ASA from IVa individuals. In addition, differences in peptide and/or posttranslational modification unrelated to the N -linked carbohydrate or phosphorylation exist between the fibroblast ASA from IIIa and IVa individuals. The finding that both fibroblasts and platelets exhibit related electrophoretic isoform patterns characteristic of the donor's ASA type allows for the use of fibroblasts to study the impact of ethanol on the metabolism of cells possessing different ASA types. 相似文献