全文获取类型
收费全文 | 11121篇 |
免费 | 718篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 360篇 |
妇产科学 | 449篇 |
基础医学 | 1330篇 |
口腔科学 | 119篇 |
临床医学 | 1891篇 |
内科学 | 2018篇 |
皮肤病学 | 91篇 |
神经病学 | 1032篇 |
特种医学 | 262篇 |
外国民族医学 | 1篇 |
外科学 | 902篇 |
综合类 | 135篇 |
一般理论 | 20篇 |
预防医学 | 1720篇 |
眼科学 | 127篇 |
药学 | 563篇 |
中国医学 | 6篇 |
肿瘤学 | 738篇 |
出版年
2023年 | 86篇 |
2022年 | 119篇 |
2021年 | 233篇 |
2020年 | 178篇 |
2019年 | 267篇 |
2018年 | 305篇 |
2017年 | 225篇 |
2016年 | 239篇 |
2015年 | 250篇 |
2014年 | 367篇 |
2013年 | 537篇 |
2012年 | 795篇 |
2011年 | 773篇 |
2010年 | 427篇 |
2009年 | 428篇 |
2008年 | 720篇 |
2007年 | 776篇 |
2006年 | 737篇 |
2005年 | 744篇 |
2004年 | 677篇 |
2003年 | 704篇 |
2002年 | 613篇 |
2001年 | 82篇 |
2000年 | 60篇 |
1999年 | 104篇 |
1998年 | 132篇 |
1997年 | 99篇 |
1996年 | 112篇 |
1995年 | 67篇 |
1994年 | 67篇 |
1993年 | 63篇 |
1992年 | 63篇 |
1991年 | 42篇 |
1990年 | 50篇 |
1989年 | 70篇 |
1988年 | 42篇 |
1987年 | 47篇 |
1986年 | 37篇 |
1985年 | 49篇 |
1984年 | 40篇 |
1983年 | 42篇 |
1982年 | 64篇 |
1981年 | 36篇 |
1980年 | 41篇 |
1979年 | 21篇 |
1978年 | 24篇 |
1977年 | 19篇 |
1976年 | 18篇 |
1975年 | 20篇 |
1974年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Angiotensin-converting enzyme (ACE) gene polymorphism in type II diabetic patients with increased albumin excretion rate 总被引:1,自引:0,他引:1
Sianna Panagiotopoulos Trudy Jeanne Smith G. Peter Aldred Elizabeth Jane Baker Carolyn Jane Jacklin George Jerums 《Journal of diabetes and its complications》1995,9(4):272-276
Approximately one in three patients with diabetes is at risk of developing kidney disease, despite current methods of treatment. It has long been suspected that diabetic kidney disease has a genetic basis, but this has been difficult to prove. Polymorphisms of the angiotensin-converting enzyme (ACE) gene have been shown to be related to the occurrence of nephropathy in type I diabetic patients. This study showed that there was no association in the ACE genotype frequency and increased albumin excretion rate in type II diabetic patients. 相似文献
52.
In the not-so-distant past the skin was generally viewed as a passive target for immune-mediated injury. Over the last decade, however, concepts of a previously unrecognized role for the skin have unfolded, whereby resident bone marrow-derived leukocytes (e.g. Langerhans cells and T cells) initiate and regulate the immune responses that protect it. Their combination with other immunomodulatory resident cells (e.g. keratinocytes, melanocytes, endothelial cells, fibroblasts) led to the idea that the skin may function as a self-sustaining lymphoid tissue. Although T lymphocytes or, at least, certain subpopulations thereof have the general propensity to populate epithelial tissues, there exist major species differences regarding the phenotype of intraepidermal T cells. The purpose of this review is to fill gaps in our understanding of the relationship of rodent skin T cells to T cells identified in human skin and the normal physiologic and pathologic role(s) of these cells. 相似文献
53.
Michael A Tangrea Rodrigo F Chuaqui John W Gillespie Mamoun Ahram Gallya Gannot Benjamin S Wallis Carolyn J M Best W Marston Linehan Lance A Liotta Thomas J Pohida Robert F Bonner Michael R Emmert-Buck 《Diagnostic molecular pathology》2004,13(4):207-212
Tissue microdissection is an important method for the study of disease states. However, it is difficult to perform high-throughput molecular analysis with current techniques. We describe here a prototype version of a novel technique (expression microdissection) that allows for the procurement of desired cells via molecular targeting. Expression microdissection (xMD) offers significant advantages over available methods, including an increase in dissection speed of several orders of magnitude. xMD may become a valuable tool for investigators studying cancer or other disease states in patient specimens and animal models. 相似文献
54.
Koumans EH Black CM Markowitz LE Unger E Pierce A Sawyer MK Papp JR 《Journal of clinical microbiology》2003,41(4):1507-1511
55.
Chinese hamster cells deficient in ornithine decarboxylase activity: Reversion by gene amplification and by azacytidine treatment 总被引:11,自引:0,他引:11
A group of Chinese hamster ovary (CHO) cell mutants deficient in ornithine decarboxylase (ODC) activity are described and compared to the prototype mutant reported previously (21). Although all mutants belong to the same complementation group, they can be divided into two classes: those with some residual enzyme activity and those with no activity. All mutants are putrescine auxotrophs, but they differ in their ability to utilize the enzyme's substrate, ornithine, a property which correlates with the amount of residual enzyme activity. The mutants also differ in their frequency of reversion to prototrophy. The leaky mutants revert at a high rate by overproducing a partially defective enzyme by a gene amplification mechanism similar to that leading to the ornithine analog-resistant mutants which have elevated enzyme levels. Spontaneous reversion in the null mutants is rare. However, one null mutant, which was induced with ethyl methane sulfonate and which makes ODC mRNA but no active enzyme, is nevertheless revertible with 5-azacytidine. We conclude that CHO cells are at least diploid at the ODC locus, but that only one allele is active. Further studies suggest the possibility that ethyl methane sulfonate is not just a classical mutagen but may also induce gene inactivations that are revertible by 5-azacytidine. 相似文献
56.
57.
Yvonne Myal Carolyn Gregory Hui Wang John L. Hamerton Robert P. C. Shiu 《Somatic Cell and Molecular Genetics》1989,15(3):265-270
The hormonally responsive prolactin-inducible protein (PIP), gene is expressed in benign and malignant breast tumor tissues and in such normal exocrine organs as sweat, salivary, and lacrimal glands. In this communication we report the regional chromosome localization of the PIPgene locus to chromosome 7 by Southern hybridization to DNA from human-hamster somatic cell hybrids, and to 7q32–36 by in situ hybridization. 相似文献
58.
59.
Dean K Whitla Gary Orfield William Silen Carole Teperow Carolyn Howard Joan Reede 《Academic medicine》2003,78(5):460-466
PURPOSE: Many U.S. medical schools have abandoned affirmative action, limiting the recruitment and reducing the admission of underrepresented minority (URM) students even though research supports the premise that the public benefits from an increase in URM physicians and that URM physicians are likely to serve minority, poor, and Medicaid populations. Faculty and students commonly assume they benefit from peer cultural exchange, and the published evidence for the past two decades supports this notion. This research examined the students' perceptions of the educational merits of a diverse student body by surveying medical students at two schools. METHOD: In 2000, medical students from all four years at Harvard Medical School and the University of California, San Francisco, School of Medicine were enrolled in a telephone survey about the relevance of racial diversity (among students) in their medical education. Students responded to the interviewer's questions on a five-point Likert-type scale. RESULTS: Of the 55% of students who could be located, 97% responded to the survey. Students reported having little intercultural contact during their formative years but significantly more interactions during higher education years, especially in medical school. Students reported contacts with diverse peers greatly enhanced their educational experience. They strongly supported strengthening or maintaining current affirmative action policies in admissions. The responses and demography of the Harvard and UCSF students did not differ significantly, nor did they differ for majority students and URM students-all groups overwhelmingly thought that racial and ethnic diversity among their peers enhanced their education. CONCLUSIONS: Diversity in the student body enhanced the educational experiences of students in two U.S. medical schools. 相似文献
60.