全文获取类型
收费全文 | 8018篇 |
免费 | 802篇 |
国内免费 | 1篇 |
出版年
2023年 | 49篇 |
2022年 | 157篇 |
2021年 | 268篇 |
2020年 | 137篇 |
2019年 | 134篇 |
2018年 | 157篇 |
2017年 | 141篇 |
2016年 | 248篇 |
2015年 | 376篇 |
2014年 | 417篇 |
2013年 | 508篇 |
2012年 | 639篇 |
2011年 | 670篇 |
2010年 | 355篇 |
2009年 | 329篇 |
2008年 | 391篇 |
2007年 | 406篇 |
2006年 | 393篇 |
2005年 | 338篇 |
2004年 | 318篇 |
2003年 | 295篇 |
2002年 | 297篇 |
2001年 | 105篇 |
2000年 | 99篇 |
1999年 | 106篇 |
1998年 | 80篇 |
1997年 | 62篇 |
1996年 | 63篇 |
1995年 | 62篇 |
1994年 | 44篇 |
1993年 | 48篇 |
1992年 | 61篇 |
1991年 | 51篇 |
1990年 | 63篇 |
1989年 | 61篇 |
1988年 | 62篇 |
1987年 | 55篇 |
1986年 | 53篇 |
1985年 | 57篇 |
1984年 | 47篇 |
1983年 | 40篇 |
1982年 | 36篇 |
1981年 | 43篇 |
1980年 | 37篇 |
1979年 | 35篇 |
1977年 | 32篇 |
1976年 | 41篇 |
1975年 | 32篇 |
1974年 | 32篇 |
1973年 | 30篇 |
排序方式: 共有8821条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Summary The degree of satellite association was found to be significantly higher in phytohemagglutinin (PHA)-stimulated lymphocytes from cystic fibrosis (CF) patients than from those of control individuals. PHA-stimulated lymphocytes from obligatory heterozygotes for the CF mutant allele showed an intermediate degree of satellite association. The degree of satellite association was estimated by the frequency of cells exhibiting associations, by the number of associations per cell, and by the number of chromosomes in an association. The differences in the degree of satellite association were dependent on the concentration of colchicine used for cell arrest. These findings may assist in developing a diagnostic method for the early identification of heterozygotes for the CF allele and for prenatal detection of CF homozygous fetuses.This paper is based on a portion of a dissertation to be submitted by Y. Ravia in partial fulfilment of the Ph. D. requirements in the Graduate School of Tel Aviv University 相似文献
5.
Rachel J. Primrose Toral Zaveri Alyssa J. Bakke Gregory R. Ziegler Howard R. Moskowitz John E. Hayes 《PloS one》2016,11(3)
Vaginal microbicides potentially empower women to protect themselves from HIV and other sexually transmitted infections (STIs), especially when culture, religion, or social status may prevent them from negotiating condom use. The open literature contains minimal information on factors that drive user acceptability of women’s health products or vaginal drug delivery systems. By understanding what women find to be most important with regard to sensory properties and product functionality, developers can iteratively formulate a more desirable product. Conjoint analysis is a technique widely used in market research to determine what combination of elements influence a consumer’s willingness to try or use a product. We applied conjoint analysis here to better understand what sexually-active woman want in a microbicide, toward our goal of formulating a product that is highly acceptable to women. Both sensory and non-sensory attributes were tested, including shape, color, wait time, partner awareness, messiness/leakage, duration of protection, and functionality. Heterosexually active women between 18 and 35 years of age in the United States (n = 302) completed an anonymous online conjoint survey using IdeaMap software. Attributes (product elements) were systematically presented in various combinations; women rated these combinations of a 9-point willingness-to-try scale. By coupling systematic combinations and regression modeling, we can estimate the unique appeal of each element. In this population, a multifunctional product (i.e., broad spectrum STI protection, coupled with conception) is far more desirable than a microbicide targeted solely for HIV protection; we also found partner awareness and leakage are potentially strong barriers to use. 相似文献
6.
7.
8.
9.
10.