全文获取类型
收费全文 | 18397篇 |
免费 | 1394篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 112篇 |
儿科学 | 551篇 |
妇产科学 | 511篇 |
基础医学 | 2692篇 |
口腔科学 | 344篇 |
临床医学 | 2110篇 |
内科学 | 3643篇 |
皮肤病学 | 325篇 |
神经病学 | 1928篇 |
特种医学 | 594篇 |
外科学 | 1736篇 |
综合类 | 159篇 |
现状与发展 | 1篇 |
一般理论 | 20篇 |
预防医学 | 2012篇 |
眼科学 | 288篇 |
药学 | 1424篇 |
中国医学 | 56篇 |
肿瘤学 | 1327篇 |
出版年
2024年 | 26篇 |
2023年 | 242篇 |
2022年 | 383篇 |
2021年 | 675篇 |
2020年 | 462篇 |
2019年 | 733篇 |
2018年 | 715篇 |
2017年 | 569篇 |
2016年 | 561篇 |
2015年 | 612篇 |
2014年 | 798篇 |
2013年 | 1032篇 |
2012年 | 1646篇 |
2011年 | 1556篇 |
2010年 | 802篇 |
2009年 | 757篇 |
2008年 | 1212篇 |
2007年 | 1222篇 |
2006年 | 1023篇 |
2005年 | 1084篇 |
2004年 | 936篇 |
2003年 | 803篇 |
2002年 | 761篇 |
2001年 | 121篇 |
2000年 | 60篇 |
1999年 | 98篇 |
1998年 | 125篇 |
1997年 | 121篇 |
1996年 | 71篇 |
1995年 | 69篇 |
1994年 | 64篇 |
1993年 | 54篇 |
1992年 | 41篇 |
1991年 | 30篇 |
1990年 | 37篇 |
1989年 | 27篇 |
1988年 | 31篇 |
1987年 | 35篇 |
1986年 | 32篇 |
1985年 | 21篇 |
1984年 | 16篇 |
1983年 | 10篇 |
1982年 | 27篇 |
1981年 | 21篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1978年 | 9篇 |
1977年 | 11篇 |
1975年 | 8篇 |
1972年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Jennifer L. Brown Lisa B. Haddad Nicole K. Gause Sarah Cordes Cecilia Bess Caroline C. King 《Women & health》2019,59(3):305-317
This study qualitatively examined factors that influenced contraceptive choices in a sample of young, HIV-infected women. Individual qualitative interviews were conducted among 30 vertically and horizontally HIV-infected women (n = 26 African American) from the ages of 14 to 24 years (Mean age = 20.9 years). We recruited sample groups with the following characteristics: (a) current contraceptive/condom use with ≥1 child (n = 11); (b) current contraceptive/condom use with no children (n = 12); and (c) no current contraceptive/condom use with no children (n = 7). A semi-structured interview guide was used to ask participants about factors influencing past and current contraceptive choices. Individual interviews were digitally recorded and transcribed verbatim; analyses to identify core themes were informed by the Grounded Theoretical approach. Young, HIV-infected women did not identify their HIV serostatus or disease-related concerns as influential in their contraceptive decisions. However, they reported that recommendations from health-care providers and input from family and friends influenced their contraceptive choices. They also considered a particular method’s advantages (e.g., menstrual cycle improvements) and disadvantages (e.g., increased pill burden) when selecting a method. Findings suggested that HIV-infected young women’s contraceptive decisions were influenced by factors other than those related to their infection. 相似文献
12.
Caroline A. Harrison BMedSci MRCS ; Martin J. Heaton MD FRCS ; Christopher M. Layton PhD ; Sheila Mac Neil PhD 《Wound repair and regeneration》2006,14(2):203-209
To produce a stable epidermis, keratinocytes need to be firmly attached to the basement membrane. However, following wounding, keratinocytes are required to develop a migratory phenotype in order to reepithelialize the wound. To investigate some of the issues underlying reepithelialization, we have developed a three-dimensional in vitro model of tissue-engineered skin, comprising sterilized human dermis seeded with human keratinocytes and dermal fibroblasts. Using this model, we have shown that the inclusion of fibroblasts within the model increases the stability of keratinocyte attachment. We have also demonstrated that keratinocyte migration occurs most effectively in the absence of a basement membrane and following the inclusion of fibroblasts in the model. In addition, subjecting the keratinocyte layer to mechanical trauma induces a migratory phenotype. We conclude that this three-dimensional in vitro wound model can be used to increase our understanding of the factors that enhance keratinocyte migration and hence wound healing in vivo. 相似文献
13.
Human and mouse genomes contain more than 20 related genes encoding diverse type I interferons (IFNs- alpha/beta), cytokines that are crucial for resistance of organisms against viral infections. Although the amino acid sequences of various IFN-alpha/beta subtypes differ markedly, they are all considered to share a common three-dimensional structure and to bind the same heterodimeric receptor, composed of the IFNAR-1 and IFNAR-2 subunits. Analysis of available mammalian IFN-beta sequences showed that they all carry 1 to 5 predicted N-glycosylation sites. Murine IFN-beta contains three predicted N-glycosylation sites (Asn29, Asn69, Asn76), one of which (Asn29) is located in the AB loop, in a region predicted to interact with the type I IFN receptor. The aim of this work was to test if this site is indeed N-glycosylated and if this glycosylation would affect IFN antiviral activity. We showed that all three N-glycosylation sites predicted from the sequence, including Asn29, carry N-linked sugars. Mutation of individual N-glycosylation sites had a weak negative influence on IFN antiviral activity. In contrast, the complete loss of glycosylation dramatically decreased activity. Our data suggest that interaction of murine IFN-beta with the IFNAR could locally differ from that of human IFN-alpha2 and human IFN-beta. 相似文献
14.
Prostatitis and male infertility are frequent disorders, and the role of prostatitis in male infertility has been under discussion for more than 30 years. Many researchers have shown relevant links between the two. Although a causal relationship has not been definitely demonstrated, increasing evidence shows that chronic prostatitis has a relevant negative impact on male fertility potential, at least in certain subgroups. In the following review, we focus on the present state of knowledge on the role of chronic prostatitis as an etiologic factor in male infertility. 相似文献
15.
16.
17.
18.
D. Caroline Blanchard Jon K. Shepherd Antonio De Padua Carobrez Robert J. Blanchard 《Neuroscience and biobehavioral reviews》1991,15(4):461-468
Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety. 相似文献
19.
20.
David S. Ball D.O. Arnold C. Friedman David S. Hartman Paul D. Radecki Dina F. Caroline 《Urologic radiology》1986,8(1):46-48
This case report illustrates the magnetic resonance imaging (MRI) appearance of a typically asymptomatic renal oncocytoma as a homogeneous mass of medium signal with a stellate central region of decreased signal, representing the central scar. The MRI was correlated with computed tomography (CT), ultrasound (US), and gross pathologic appearance. The appearance of a central scar is not specific for oncocytoma and does not exclude renal cell carcinoma, as illustrated by a second case. 相似文献