首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   533篇
  免费   36篇
  国内免费   8篇
耳鼻咽喉   12篇
儿科学   51篇
妇产科学   3篇
基础医学   57篇
口腔科学   18篇
临床医学   71篇
内科学   97篇
皮肤病学   2篇
神经病学   14篇
特种医学   137篇
外科学   22篇
综合类   8篇
预防医学   20篇
眼科学   6篇
药学   27篇
中国医学   2篇
肿瘤学   30篇
  2022年   1篇
  2021年   2篇
  2020年   3篇
  2018年   3篇
  2017年   2篇
  2016年   3篇
  2015年   7篇
  2014年   8篇
  2013年   11篇
  2012年   10篇
  2011年   10篇
  2010年   10篇
  2009年   16篇
  2008年   7篇
  2007年   11篇
  2006年   11篇
  2005年   12篇
  2004年   5篇
  2003年   8篇
  2002年   9篇
  2001年   6篇
  2000年   6篇
  1999年   9篇
  1998年   38篇
  1997年   59篇
  1996年   40篇
  1995年   32篇
  1994年   34篇
  1993年   25篇
  1992年   12篇
  1991年   10篇
  1990年   3篇
  1989年   17篇
  1988年   19篇
  1987年   16篇
  1986年   20篇
  1985年   19篇
  1984年   9篇
  1983年   6篇
  1982年   11篇
  1981年   6篇
  1980年   8篇
  1978年   6篇
  1977年   8篇
  1976年   4篇
  1975年   5篇
排序方式: 共有577条查询结果,搜索用时 140 毫秒
571.
Objective.?To determine the opinion among three groups of women (sub-fertile women, fertile women and female medical students), concerning the use of ovarian reserve tests to determine the chance of an assisted reproductive techniques' (ART) induced pregnancy or a spontaneous pregnancy.

Design.?Prospective study using questionnaires in three groups of women: patients visiting the out patient infertility clinic at the Academic Medical Centre Groningen, women who had delivered at least two children and female medical students.

Results.?The response rate varied from 63% (female medical students) to 56% (fertile women with children) and 48% (sub-fertile women). The greater part of women of all three groups found it was up to the women themselves to decide whether or not to start fertility treatment, even though the ovarian reserve test indicated little chance of success. 71% of the sub-fertile women stated that any chance justified fertility treatment. None of the three groups of women were very enthusiastic about the use of these tests for family planning.

Conclusions.?Based on results of ovarian reserve tests women could decide not to partake of a - generally demanding - fertility treatment. The outcome of the study, however, does not support this: even low chances of success are found acceptable. The ability to determine the individual ovarian reserve makes this test also a suitable device for family planning. The discussion whether these new possibilities will be useful for reproductive science will greatly depend on women's attitude towards this issue.  相似文献   
572.

BACKGROUND AND PURPOSE

Cannabidiol (CBD) has emerged as an interesting compound with therapeutic potential in several CNS disorders. However, whether it can modulate synaptic activity in the CNS remains unclear. Here, we have investigated whether CBD modulates synaptic transmission in rat hippocampal cultures and acute slices.

EXPERIMENTAL APPROACH

The effect of CBD on synaptic transmission was examined in rat hippocampal cultures and acute slices using whole cell patch clamp and standard extracellular recordings respectively.

KEY RESULTS

Cannabidiol decreased synaptic activity in hippocampal cultures in a concentration-dependent and Pertussis toxin-sensitive manner. The effects of CBD in culture were significantly reduced in the presence of the cannabinoid receptor (CB1) inverse agonist, LY320135 but were unaffected by the 5-HT1A receptor antagonist, WAY100135. In hippocampal slices, CBD inhibited basal synaptic transmission, an effect that was abolished by the proposed CB1 receptor antagonist, AM251, in addition to LY320135 and WAY100135.

CONCLUSIONS AND IMPLICATIONS

Cannabidiol reduces synaptic transmission in hippocampal in vitro preparations and we propose a role for both 5-HT1A and CB1 receptors in these CBD-mediated effects. These data offer some mechanistic insights into the effects of CBD and emphasize that further investigations into the actions of CBD in the CNS are required in order to elucidate the full therapeutic potential of CBD.  相似文献   
573.

Objective

Atherosclerosis is a chronic inflammatory process. Poly(ADP-ribose) polymerase-1 (PARP), a nuclear enzyme linked to DNA repair, has been shown to be involved in atherogenesis; however, the effects on dendritic cells, T cells and serum auto-antibody levels are not fully understood.

Methods

Male Apoe-/- mice on a western diet were treated with the PARP inhibitor 1NO-1001 (n = 15), while the control group (n = 15) received 5% glucose solution for 10 weeks.

Results

Inhibition of PARP markedly reduced atherosclerotic lesion development (p = 0.001). Immunohistochemistry and mRNA analysis revealed a reduced inflammatory compound inside the lesion. Focusing on dendritic cells, INO-1001 reduced number of cells (p = 0.04), grade of activation, represented by I/12 (p = 0.04) and Cd83 (p = 0.03), and grade of attraction, represented by Mip3α (p = 0.02) in the plaque. Furthermore, INO-1001 decreased number of T lymphocyte (p = 0.003) in the lesion and grade of activation after stimulation with oxLDL in vitro. Moreover, serum IgM antibody levels to oxLDL were significantly lower in INO-1001 treated mice (p = 0.03).

Conclusions

Functional blockade of PARP by INO-1001 reduces atherosclerotic lesion development. The anti-atherogenic effect is beside already known mechanisms also moderated due to modulation of DC and T cell invasion and activation, DC attraction as well as IgM antibody levels to oxLDL.  相似文献   
574.
Fifteen plant species were collected from the Nelspruit Botanical Garden based on a list of plants provided by Phytomedicine Programme at the University of Pretoria and their ethnopharmacological information. Hexane, dichloromethane (DCM), acetone and methanolic extracts were screened for antimycobacterial activity against Mycobacterium smegmatis. The acetone extract of Milletia stulhimannii was the most active, showing activity against Mycobacterium smegmatis with minimum inhibitory concentration (MIC) value of 0.13 mg/ml. Acetone extracts for all plants had lower MIC values ranging between 0.11–1.25 mg/ml against M. smegmatis. Milletia stulhimannii, Albizia gummifera, Xanthocercis zambesiaca and Barringtonia racemosa have shown great potential as anti-tuberculosis agents. They were active against M. smegmatis with average MIC values of acetone extracts of 0.13 mg/ml.  相似文献   
575.
OBJECTIVE: To determine whether boys meeting diagnostic criteria for juvenile mania and attention deficit hyperactivity disorder (mania-ADHD) may be distinguished from boys with ADHD alone on a range of clinical and family variables. METHODOLOGY: Boys aged 9-13 years with mania-ADHD (n = 25), ADHD alone (n = 99), or no psychiatric diagnosis (n = 27) were compared on parent and teacher report Child Behavior Checklists (CBCL) and Conners Questionnaires, self-report CBCLs, patterns of comorbidity, intellectual functioning, and family variables. RESULTS: Mania-ADHD subjects had significantly higher mean ratings than ADHD only subjects on the parent CBCL for the Withdrawn, Thought Problems, Delinquent Behavior and Aggressive Behavior scales and significantly higher rates of comorbid depression, anxiety and psychotic symptoms. Other variables did not distinguish the mania-ADHD and ADHD only groups. CONCLUSIONS: These data confirm previous research indicating that the CBCL may be used to assist in the clinical identification of manic children.  相似文献   
576.
OBJECTIVE: This study compared the clinical efficacy of 4% articaine (A200) and 0.5% bupivacaine (B200), both with 1:200,000 epinephrine, for lower third molar removal. STUDY DESIGN: Fifty patients underwent removal of symmetrically positioned lower third molars, in 2 separate appointments, under local anesthesia either with A200 or B200, in a double-blind, randomized, and crossover manner. Time to onset, duration of postoperative analgesia, duration of anesthetic action on soft tissues, intraoperative bleeding, and hemodynamic parameters were evaluated. RESULTS: A statistically significant difference between the time to onset of A200 (1.66 +/- 0.13 minutes) and B200 (2.51 +/- 0.21 minutes) was found (P < .05). There was no statistically significant difference in the duration of analgesia, whether the patient was subjected to osteotomy or not, regardless of the local anesthetic used (3 to 4 hours; P > .05). However, when patients received B200 they experienced a statistically significant longer period of anesthesia on the soft tissues as compared with when they had received A200 (around 5 hours and 4 hours, respectively, P < .05). The surgeon's rating of intraoperative bleeding was considered very close to minimal for both anesthetics. In the surgeries with osteotomy, the comparison between A200 and B200 showed statistically significant differences in the diastolic (64 mm Hg and 68 mm Hg, respectively, P = .001) and mean arterial pressure (86 mm Hg and 89 mm Hg, respectively, P = .031) when data from all the surgical phases were pooled. Additionally, the mouth opening at the suture removal was statistically different for A200 and B200 solutions (91.90% +/- 3.00% and 88.57% +/- 2.38% of the preoperative measure, respectively) when surgeries required bone removal (P < .05). CONCLUSIONS: In comparison with 0.5% bupivacaine, 4% articaine (both with 1:200,000 epinephrine) provided a shorter time to onset and comparable hemostasis and postoperative pain control with a shorter duration of soft tissue anesthesia in lower third molar removal.  相似文献   
577.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号