全文获取类型
收费全文 | 6403篇 |
免费 | 383篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 55篇 |
儿科学 | 344篇 |
妇产科学 | 145篇 |
基础医学 | 713篇 |
口腔科学 | 103篇 |
临床医学 | 495篇 |
内科学 | 1374篇 |
皮肤病学 | 124篇 |
神经病学 | 338篇 |
特种医学 | 345篇 |
外科学 | 1215篇 |
综合类 | 141篇 |
一般理论 | 3篇 |
预防医学 | 278篇 |
眼科学 | 138篇 |
药学 | 514篇 |
1篇 | |
中国医学 | 7篇 |
肿瘤学 | 469篇 |
出版年
2023年 | 49篇 |
2022年 | 73篇 |
2021年 | 182篇 |
2020年 | 92篇 |
2019年 | 181篇 |
2018年 | 205篇 |
2017年 | 126篇 |
2016年 | 146篇 |
2015年 | 150篇 |
2014年 | 245篇 |
2013年 | 250篇 |
2012年 | 384篇 |
2011年 | 418篇 |
2010年 | 224篇 |
2009年 | 201篇 |
2008年 | 312篇 |
2007年 | 261篇 |
2006年 | 268篇 |
2005年 | 259篇 |
2004年 | 245篇 |
2003年 | 202篇 |
2002年 | 190篇 |
2001年 | 131篇 |
2000年 | 145篇 |
1999年 | 154篇 |
1998年 | 70篇 |
1997年 | 89篇 |
1996年 | 77篇 |
1995年 | 49篇 |
1994年 | 54篇 |
1993年 | 51篇 |
1992年 | 108篇 |
1991年 | 111篇 |
1990年 | 85篇 |
1989年 | 110篇 |
1988年 | 91篇 |
1987年 | 81篇 |
1986年 | 78篇 |
1985年 | 92篇 |
1984年 | 59篇 |
1983年 | 54篇 |
1982年 | 32篇 |
1981年 | 30篇 |
1979年 | 26篇 |
1977年 | 24篇 |
1974年 | 34篇 |
1973年 | 38篇 |
1972年 | 27篇 |
1969年 | 25篇 |
1968年 | 27篇 |
排序方式: 共有6802条查询结果,搜索用时 31 毫秒
61.
62.
BACKGROUND: Previous studies of attempted suicide have suggested that cultural and social factors play a significant role in the causation of deliberate self-harm. METHOD: In order to measure elements of culture conflict two inter-group comparisons were undertaken. In the first, 27 Asian women who had presented to hospital services following attempted suicide (Asian group) were matched with a group of similar age Asian women attending GP surgeries for other reasons (Asian GP attenders group). The second comparison was between the Asian and 46 White attempters. RESULTS: On comparing Asian attempters with Asian GP attenders group the former were more likely to have a history of previous suicidal behaviour, to have a psychiatric diagnosis, and be unemployed. Their parents were more likely to have arrived in the United Kingdom at an older age. In addition, those who attempted suicide were more likely to have been in an inter-racial relationship and to have changed religions. In the second inter-group comparison, the characteristics of Asian and White suicide attempt patients were examined. White attempters were more likely to have mental illness, and were more likely to use alcohol as part of the method of attempted suicide. By contrast, Asian attempters had experienced life events pertaining to relationships, took fewer tablets and yet expressed greater regret at not succeeding in the attempt. CONCLUSIONS: Although numbers are small, social stress and other cultural factors play an important role in the act of deliberate self-harm. 相似文献
63.
64.
Surface-immobilized polyethylene oxide for bacterial repellence. 总被引:1,自引:0,他引:1
Polyethylene terephthalate films were surface-modified with polyethylene oxide (18,500 g/mol) using a solution technique described previously. These films were investigated for their resistance to bacterial adhesion. Three bacterial strains most commonly associated with implant infections, Staphylococcus epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa, were cultured in tryptic soya broth, human plasma and human serum on the polymeric substrates. Significant reductions (between 70 and 95%) in adherent bacteria were observed on the polyethylene oxide-modified substrates compared to the untreated control polyethylene terephthalate. Surface modification with polyethylene oxide may reduce the risk of implant-associated infections. Plasma fibrinogen was observed to play an important role in the adhesion of all three of these species on both the polyethylene oxide-modified and control polyethylene terephthalate materials. 相似文献
65.
66.
Animal studies of the topical application of adenosine A
2A
receptor agonists show that it promotes wound closure. To further confirm the efficacy of adenosine A
2A
receptor agonists as promoters of wound healing, we compared the effect of MRE0094, a novel selective adenosine A
2A
receptor agonist, to CGS-21680, a reference selective adenosine A
2A
receptor agonist, as well as to recombinant human platelet–derived growth factor (0.01% Becaplermin gel), an agent currently used to promote healing of diabetic ulcers, on wound closure in healthy BALB/C mice. Wounds (12 mm diameter) were created on the dorsum of mice (two per mouse) and then treated daily with vehicle, 0.01% Becaplermin gel, or different doses of the adenosine A
2A
receptor agonists. The wound margins were traced onto plastic sheets, and the wound areas were digitized, quantitated, and compared. We found that application of MRE0094 (1 g/wound and 10 g/wound) and CGS-21680 (1 g/wound and 5 g/wound) achieved 50% wound closure significantly more rapidly than control application (day 1.9, 1.9, 3.5, 3.2, respectively, versus control day 4, p < 0.05 ANOVA). Surprisingly, neither higher nor lower concentrations of CGS-21680 affected the rate of wound closure, as compared to control. In contrast, Becaplermin gel did not increase the rate at which wounds closed (50% closure by day 7.2, p = NS versus control). These data confirm our prior observations that adenosine A
2A
receptor agonists promote wound closure, and they suggest that these agents may be as effective if not more effective than Becaplermin gel for the treatment of poorly healing wounds. 相似文献
67.
Evenomation by arachnids of the genus Loxosceles frequently results in disfiguring necrotic skin lesions. The cellular and molecular mechanisms which contribute to lesion development are incompletely defined but appear to involve participation of several pro-inflammatory mediators. We have recently observed that Loxosceles deserta venom induces the production of chemokines in human umbilical vein endothelial cells (HUVECs) and human pulmonary epithelial cells. In the present study we observed that Loxosceles deserta venom induces the expression of vascular endothelial growth factor (VEGF) in human keratinocytes but little in smooth muscle cells and none in pulmonary epithelial cells. A potent endothelial cell-specific mitogen, VEGF induces angiogenesis and vascular permeability in vivo. RNase protection assay data indicate that VEGF mRNA concentrations in keratinocytes are significantly increased at 2 h following venom exposure. These data suggest that keratinocyte-derived VEGF may contribute to the vasodilation, edema and erythema which occur following Loxosceles evenomation. 相似文献
68.
Goldfarb JM Austin C Peskin B Lisbona H Desai N de Mola JR 《Human reproduction (Oxford, England)》2000,15(5):1075-1078
The purpose of our study was to review and evaluate retrospectively the experience of an in-vitro fertilization (IVF) surrogate gestational programme in a tertiary care and academic centre. In a 15 year period from 1984 to 1999, a total of 180 cycles of IVF surrogate gestational pregnancy was started in 112 couples. On average, the women were 34.4 +/- 4.4 years of age, had 11.1 +/- 0.72 oocytes obtained per retrieval, 7.1 +/- 0.5 oocytes fertilized and 5. 8 +/- 0.4 embryos subsequently cleaved. Sixteen cycles (8.9%) were cancelled due to poor stimulation. Except for six cycles (3.3%) where there were no embryos available, an average of 3.2 +/- 0.1 embryos was transferred to each individual recipient. The overall pregnancy rate per cycle after IVF surrogacy was 24% (38 of 158), with a clinical pregnancy rate of 19% (30 of 158), and a live birth rate of 15.8% (25 of 158). When compared to patients who underwent a hysterectomy, individuals with congenital absence of the uterus had significantly more oocytes retrieved (P < 0.006), fertilized, cleaved and more embryos available for transfer despite being of comparable age. IVF surrogate gestation is an established, yet still controversial, approach to the care of infertile couples. Take-home baby rates are comparable to conventional IVF over the same 15 year span in our programme. Patients with congenital absence of the uterus responded to ovulation induction better than patients who underwent a hysterectomy, perhaps due in part to ovarian compromise from previous surgical procedures. 相似文献
69.
Distinct proinflammatory host responses to Neisseria gonorrhoeae infection in immortalized human cervical and vaginal epithelial cells 总被引:4,自引:0,他引:4 下载免费PDF全文
In this study we utilized immortalized morphologically and functionally distinct epithelial cell lines from normal human endocervix, ectocervix, and vagina to characterize gonococcal epithelial interactions pertinent to the lower female genital tract. Piliated, but not nonpiliated, N. gonorrhoeae strain F62 variants actively invaded these epithelial cell lines, as demonstrated by an antibiotic protection assay and confocal microscopy. Invasion of these cells by green fluorescent protein-expressing gonococci was characterized by colocalization of gonococci with F actin, which were initially detected 30 min postinfection. In all three cell lines, upregulation of interleukin 8 (IL-8) and IL-6, intercellular adhesion molecule 1 (CD54), and the nonspecific cross-reacting antigen (CD66c) were detected 4 h after infection with piliated and nonpiliated gonococci. Furthermore, stimulation of all three cell lines with gonococcal whole-cell lysates resulted in a similar upregulation of IL-6 and IL-8, confirming that bacterial uptake is not essential for this response. Increased levels of IL-1 were first detected 8 h after infection with gonococci, suggesting that the earlier IL-8 and IL-6 responses were not mediated through the IL-1 signaling pathway. The IL-1 response was limited to cultures infected with piliated gonococci and was more vigorous in the endocervical epithelial cells. The ability of gonococci to stimulate distinct proinflammatory host responses in these morphologically and functionally different compartments of the lower female genital tract may contribute directly to the inflammatory signs and symptoms characteristic of disease caused by N. gonorrhoeae. 相似文献
70.
Bhattacharya S; MacLennan F; Hamilton MP; Templeton A 《Human reproduction (Oxford, England)》1997,12(7):1440-1442
Although the conventional method of pain relief during outpatient oocyte
recovery involves physician-administered drugs, patient- controlled
analgesia (PCA) offers an alternative technique with the potential to give
women more control over peroperative analgesia. We conducted a prospective
randomized study to compare the effect of fentanyl administered either
through a PCA delivery system or by a physician. Thirty-nine women were
randomized to PCA during egg collection while 42 were allocated to receive
intermittent doses administered by a physician. Pain was evaluated by means
of a 100 mm linear analogue scale. The mean (SD) pain score in the PCA
group was 38.5 (19.8) while in the other group it was 46.1 (21.3) (P =
0.1). In the PCA group, 64% of women felt very satisfied with their
analgesia as compared with 57% in the non-PCA group (P = 0.6). Among the
PCA users, 39% of demands were successful. Significantly more fentanyl
(97.5 microg) was used in the PCA group than in the other group (84.6
microg) (P = 0.03). Though intraoperative PCA with fentanyl is an effective
alternative to physician-administered techniques, many women still feel the
need for more analgesia during the procedure.
相似文献