全文获取类型
收费全文 | 126020篇 |
免费 | 8249篇 |
国内免费 | 536篇 |
专业分类
耳鼻咽喉 | 1336篇 |
儿科学 | 3725篇 |
妇产科学 | 2086篇 |
基础医学 | 16966篇 |
口腔科学 | 2248篇 |
临床医学 | 12366篇 |
内科学 | 26605篇 |
皮肤病学 | 1562篇 |
神经病学 | 12308篇 |
特种医学 | 3916篇 |
外国民族医学 | 9篇 |
外科学 | 18140篇 |
综合类 | 1670篇 |
现状与发展 | 1篇 |
一般理论 | 156篇 |
预防医学 | 10878篇 |
眼科学 | 3339篇 |
药学 | 8838篇 |
1篇 | |
中国医学 | 281篇 |
肿瘤学 | 8374篇 |
出版年
2023年 | 618篇 |
2022年 | 1082篇 |
2021年 | 2404篇 |
2020年 | 1440篇 |
2019年 | 2438篇 |
2018年 | 2860篇 |
2017年 | 2077篇 |
2016年 | 2414篇 |
2015年 | 2787篇 |
2014年 | 4017篇 |
2013年 | 5649篇 |
2012年 | 8606篇 |
2011年 | 9226篇 |
2010年 | 5043篇 |
2009年 | 4714篇 |
2008年 | 8116篇 |
2007年 | 8624篇 |
2006年 | 8176篇 |
2005年 | 8229篇 |
2004年 | 7774篇 |
2003年 | 7173篇 |
2002年 | 6922篇 |
2001年 | 1298篇 |
2000年 | 997篇 |
1999年 | 1326篇 |
1998年 | 1484篇 |
1997年 | 1269篇 |
1996年 | 970篇 |
1995年 | 967篇 |
1994年 | 837篇 |
1993年 | 821篇 |
1992年 | 741篇 |
1991年 | 666篇 |
1990年 | 592篇 |
1989年 | 553篇 |
1988年 | 546篇 |
1987年 | 541篇 |
1986年 | 479篇 |
1985年 | 547篇 |
1984年 | 608篇 |
1983年 | 547篇 |
1982年 | 711篇 |
1981年 | 621篇 |
1980年 | 543篇 |
1979年 | 396篇 |
1978年 | 364篇 |
1977年 | 372篇 |
1976年 | 304篇 |
1975年 | 286篇 |
1974年 | 293篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
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
42.
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
43.
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
44.
45.
This study examined the relations betweensociotropy, autonomy, and stress severity ratings forhypothetical life events that were objectivelycategorized as interpersonal or achievement-related infocus. The hypothesis that sociotropy and autonomyserve as vulnerability factors to dysphoria in thepresence of life stress that matches the theme of thevulnerability was also examined in 6-week and 12-week follow-up evaluations. Results provided onlypartial support for the predicted relations amongsociotropy, autonomy, and perceived stress severityratings of interpersonal and achievement-related events. Longitudinal results failed to support thehypothesis that sociotropy and autonomy serve asvulnerability factors for matching interpersonal andachievement-related stress. It was concluded thatobjectively categorizing life events as interpersonal orachievement-related is problematic given that themeaning of life events can vary across individuals, andthat these meanings are likely to vary partly as a function of sociotropy and autonomy. 相似文献
46.
Kevin G Becker Insong J Lee James W Nagle Rachel D Canning Ameer M Gado Rosarelis Torres Mihael H Polymeropoulos Paul T Massa WilliamE Biddison Paul D Drew 《International journal of developmental neuroscience》1997,15(7):73
We describe a novel human zinc finger cNDA, C2H2-171. This cDNA represents an mRNA which encodes a protein of 484 amino acids and a calculated molecular weight of 54 kD. Four zinc finger-like domains are found in the C-terminal end of the protein. At the N-terminus, C2H2-171 contains a POZ/tramtrack-like domain similar to that found in the tumor associated zinc finger proteins LAZ-3/BCL-6 and PLZ-F, as well as in non-zinc finger proteins. C2H2-171 RNA is preferentially expressed in the brain, and increases during the course of murine development, with maximal expression in the adult. C2H2-171 RNA is differentially expressed in brain regions, with the highest level of expression in the cerebellum. C2H2-171 RNA was expressed at high levels in primary cerebellar granule cell neurons compared to astrocytes. The gene encoding C2H2-171 is highly conserved in vertebrates, and maps to the terminus of human chromosome 1 (1q44-ter). This chromosomal location is associated with a number of cytogenetic aberrations including those involving brain developmental anomalies and tumorigenesis. These data suggest that C2H2-171 may play an important role in vertebrate brain development and function. 相似文献
47.
Frances Rudnick Levin Judith M. Hess David A. Gorelick Nancy A. Kreiter Paul J. Fudala 《The American journal on addictions / American Academy of Psychiatrists in Alcoholism and Addictions》1993,2(2):109-115
The authors systematically evaluated the frequency patterns of cocaine use in 85 cocaine-dependent outpatients and found four patterns of use: continuous (27%), intermittent patterned (35%), intermittent nonpatterned (25%), and occasional (13%). Few subjects reported consistent cycling between binges and crashes. There were no significant differences in patterns of use associated with gender, race, educational level, route of administration, or recency of heroin use. Continuous users and occasional users were older than intermittent users. Because different contingencies may control patterned vs. nonpatterned cocaine use, pattern of use may have implications for treatment, even in individuals reporting similar amounts of cocaine use. 相似文献
48.
Although a great deal is known about the nature and severity of the recent financial crisis in agriculture, there has been little systematic study of the social and psychological effects of this crisis upon farm operators and their families. Using data from a statewide sample of Iowa farmers, this study tests some hypotheses about correlates of psychological stress. The findings suggest that many farm operators find their situations to be stressful and that such stress is related to the severity of their financial problems. In addition, the life-events perspective is examined in its utility to explain how adverse economic changes impact psychological well-being. 相似文献
49.
50.
Gail Pairitz Jarvik Terri H. Beaty Paul R. Gallagher Paul M. Coates Jean A. Cortner 《Genetic epidemiology》1993,10(4):257-270
A sample enriched for familial combined hyperlipidemia (FCHL) was examined for evidence of an association between genotype at an apolipoprotein B (apoB) elevating locus defined by complex segregation analysis and FCHL. Complex segregation analysis detected a locus with a large effect on plasma apoB levels and was used to compute the most probable genotype of family members. None of the 35 normolipidemic adults carried a copy of the allele associated with elevated apoB levels, yet 58% of the 109 adults with FCHL carried 1 (29%) or 2 (28%) copies. Two of 28 (7%) normal children had 1 copy of this allele and none had 2 copies, while 88 of 182 (48%) children with FCHL had 1 (26%) or 2 (22%) copies. Further, 4l of 48 (85%) individuals classified as having hyperapobetalipoproteinemia did not carry a copy of this “elevated apoB” allele. Therefore, the presence of the allele associated with elevation of apoB level is highly predictive of FCHL and this association cannot be explained solely by the presence of elevated apoB levels in FCHL, suggesting that the locus controlling apoB levels may play an etiologic role in FCHL. © 1993 Wiley-Liss, Inc. 相似文献