全文获取类型
收费全文 | 4667篇 |
免费 | 360篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 148篇 |
妇产科学 | 208篇 |
基础医学 | 539篇 |
口腔科学 | 58篇 |
临床医学 | 907篇 |
内科学 | 887篇 |
皮肤病学 | 41篇 |
神经病学 | 374篇 |
特种医学 | 73篇 |
外科学 | 419篇 |
综合类 | 65篇 |
一般理论 | 7篇 |
预防医学 | 675篇 |
眼科学 | 44篇 |
药学 | 316篇 |
中国医学 | 5篇 |
肿瘤学 | 247篇 |
出版年
2023年 | 24篇 |
2022年 | 32篇 |
2021年 | 95篇 |
2020年 | 52篇 |
2019年 | 85篇 |
2018年 | 111篇 |
2017年 | 87篇 |
2016年 | 102篇 |
2015年 | 108篇 |
2014年 | 126篇 |
2013年 | 217篇 |
2012年 | 315篇 |
2011年 | 343篇 |
2010年 | 189篇 |
2009年 | 160篇 |
2008年 | 292篇 |
2007年 | 364篇 |
2006年 | 381篇 |
2005年 | 312篇 |
2004年 | 272篇 |
2003年 | 243篇 |
2002年 | 240篇 |
2001年 | 70篇 |
2000年 | 55篇 |
1999年 | 54篇 |
1998年 | 45篇 |
1997年 | 32篇 |
1996年 | 26篇 |
1995年 | 15篇 |
1994年 | 12篇 |
1993年 | 19篇 |
1992年 | 27篇 |
1991年 | 41篇 |
1990年 | 40篇 |
1989年 | 27篇 |
1988年 | 39篇 |
1987年 | 45篇 |
1986年 | 31篇 |
1985年 | 27篇 |
1984年 | 24篇 |
1983年 | 15篇 |
1981年 | 15篇 |
1979年 | 23篇 |
1975年 | 12篇 |
1974年 | 20篇 |
1973年 | 16篇 |
1972年 | 16篇 |
1970年 | 11篇 |
1968年 | 13篇 |
1967年 | 15篇 |
排序方式: 共有5034条查询结果,搜索用时 0 毫秒
1.
John P Elliott Hugh S Miller Suzanne Coleman Debbie Rhea Diana Abril Karen Hallbauer Niki B Istwan Gary J Stanziano 《Journal of perinatology》2005,25(10):626-630
OBJECTIVE: To assess the impact of activity restriction (AR) on the incidence of preterm birth in women treated for preterm labor testing negative for fetal fibronectin (fFN). STUDY DESIGN: Women who were diagnosed with preterm labor and tocolyzed with magnesium sulfate were concurrently screened with fFN for the purpose of subsequent management. Included were consenting patients with negative fFN, gestational age 23 0/7-33 6/7 weeks, cervical dilation < or =3 cm, and minimal vaginal bleeding. Patients were randomized to AR or no AR. Primary study outcome was incidence of preterm delivery and interval from randomization to delivery. RESULTS: A total of 73 women with negative fFN were randomized (36 with AR, 37 without AR). The overall preterm birth rate was 40%, with 44.4% of patients with AR and 35.1% of patients without AR delivering preterm, p=0.478. CONCLUSION: Maternal AR did not impact pregnancy outcome. The incidence of preterm birth in symptomatic women testing fFN negative was higher than previously reported. 相似文献
2.
3.
4.
5.
John P Elliott Niki B Istwan Ann Collins Debbie Rhea Gary Stanziano 《Journal of perinatology》2005,25(1):4-7
OBJECTIVE: To identify the etiology and impact of preterm delivery in twin gestations. STUDY DESIGN: Twin gestations delivered at 33.0 to 36.9 weeks were identified in a perinatal database, and categorized by indication for delivery. Deliveries were identified as indicated, or non-indicated (discretionary). Neonatal outcomes were measured by birth weight, length of stay, NICU admission, and ventilator utilization. Data were divided and analyzed by indicated or discretionary delivery, and gestational age at delivery. RESULTS: Analyzed were 3252 twin gestations (6504 infants), with 78% having indicated delivery. Of the 22% with discretionary delivery, nearly 40% required NICU admission. With each advancing week of gestation, there was a significant decrease in incidence of NICU admission and nursery days. CONCLUSION: The majority of preterm deliveries were indicated, though 22% were discretionary. It is vital to consider neonatal morbidity and costs related to gestational age when choosing discretionary delivery. 相似文献
6.
The effect on the correlation coefficient of discretizing data was investigated in two ways. First, the theoretical effect of dichotomizing data was calculated, and it was shown that the resulting correlation coefficient is considerably less than that between the underlying bivariate normally distributed variables. Second, computer simulations were performed of a model in which a continuous variable (measured with some error) gives rise to a counting variable through a mechanism in which the count is zero below a certain threshold value for the continuous variable and then increases linearly as the continuous variable increases. It was shown that the correlation coefficient between the observed values of the continuous and counting variables decreased as (a) the measurement error increased, (b) the slope of the relationship decreased, and (c) the number of counts decreased. It is concluded that caution is required when interpreting correlation coefficients when one or both of the variables consist of a few (say only four or five) discrete scores. 相似文献
7.
Debbie M. Popovich MSN RN CPNP Allison McAlhany MSN RN CPNP 《Newborn and Infant Nursing Reviews》2004,4(1):51
Chlamydia trachomatis is the most prevalent sexually transmitted microbial infection in the United States. The CDC estimates that 3 million people are infected annually, with approximately 50% of infected men and 75% of infected women having few or no recognized symptoms. C. trachomatis is frequently transferred from mother to infant, and the maternal-infant transfer of this disease may have negative consequences for the newborn, such as prematurity, pneumonia, and conjunctivitis. Ocular prophylaxis with silver nitrate and or antibiotics is ineffective in preventing neonatal chlamydial conjunctivitis. By increasing awareness of the potential adverse consequences, initiating screening and treatment of pregnant women, and advocating for newborn assessment and treatment, nurses can enhance the quality of care for mothers and their infants. 相似文献
8.
OBJECTIVES: The 585nm pulsed dye laser (PDL) is a promising tool for in-office laryngeal surgery. Data with respect to the safety and efficacy of the PDL for office laryngeal use is sparse. The purpose of this study is to review our experience with unsedated office PDL surgery. METHODS: Records of individuals undergoing in-office PDL between September 1, 2004, and September 1, 2006 were abstracted from a clinical database. RESULTS: Forty-seven patients underwent 117 treatments. The most common indications were recurrent respiratory papillomatosis (RRP), Reinke's edema, and vocal fold polyps. One hundred and four of 117 procedures were felt to be a success ablating all disease. Thirteen treatments required early termination. The most common factor responsible for termination was an inability to achieve a comfortable level of anesthesia. One patient with Reinke's edema developed postprocedure stridor that required a 3-day hospital admission for observation and corticosteroids. There was no incidence of any vocal fold scarring, web formation, or other complications. CONCLUSIONS: The 585nm PDL is a promising tool for in-office treatment of various laryngeal disorders. Complications are rare. 相似文献
9.
Growth factor responsiveness of human retinal pigment epithelial cells 总被引:21,自引:0,他引:21
K H Leschey S F Hackett J H Singer P A Campochiaro 《Investigative ophthalmology & visual science》1990,31(5):839-846
Growth factor effects on DNA synthesis in density-arrested human retinal pigment epithelial cells were assessed by [3H]-thymidine incorporation. Acidic and basic fibroblast growth factor and epidermal growth factor were potent stimulators, whereas platelet-derived growth factor, insulinlike growth factor-1, and insulin were weak or modest stimulators when used alone. When used in combination, each of the above growth factors caused a significant enhancement of [3H]-thymidine incorporation regardless of its effect when used alone. The combination of all four growth factors was significantly more effective than all other combinations, demonstrating synergism in their action. Similar results were found in cell proliferation assays. In contrast to this, transforming growth factor-beta inhibited the ability of each of the other growth factors and serum-containing media to stimulate [3H]-thymidine incorporation. These data suggest that DNA synthesis in human retinal pigment epithelial cells can be modulated by several growth factors, some in a stimulatory or synergistic manner and at least one in an inhibitory manner. A better understanding of these complex interactions may provide insights relevant to normal and abnormal ocular wound healing. 相似文献
10.