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   18210篇
  免费   792篇
  国内免费   105篇
耳鼻咽喉   593篇
儿科学   1222篇
妇产科学   590篇
基础医学   1491篇
口腔科学   848篇
临床医学   1513篇
内科学   3166篇
皮肤病学   496篇
神经病学   1219篇
特种医学   674篇
外国民族医学   1篇
外科学   4137篇
综合类   261篇
现状与发展   1篇
一般理论   6篇
预防医学   723篇
眼科学   505篇
药学   1026篇
中国医学   127篇
肿瘤学   508篇
  2024年   19篇
  2023年   190篇
  2022年   165篇
  2021年   314篇
  2020年   225篇
  2019年   286篇
  2018年   474篇
  2017年   398篇
  2016年   470篇
  2015年   449篇
  2014年   582篇
  2013年   822篇
  2012年   1136篇
  2011年   1372篇
  2010年   720篇
  2009年   440篇
  2008年   969篇
  2007年   1197篇
  2006年   1159篇
  2005年   1318篇
  2004年   1161篇
  2003年   1054篇
  2002年   1012篇
  2001年   554篇
  2000年   625篇
  1999年   452篇
  1998年   158篇
  1997年   112篇
  1996年   101篇
  1995年   81篇
  1994年   54篇
  1993年   41篇
  1992年   112篇
  1991年   95篇
  1990年   81篇
  1989年   69篇
  1988年   66篇
  1987年   61篇
  1986年   66篇
  1985年   52篇
  1984年   33篇
  1983年   27篇
  1979年   31篇
  1978年   21篇
  1976年   18篇
  1974年   34篇
  1973年   20篇
  1971年   21篇
  1970年   26篇
  1969年   16篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
ABSTRACT

Purpose

To investigate the effect of 1% tropicamide on anterior chamber aqueous flare (ACAF) measurements acquired with laser flare meter in patients with pseudoexfoliation.  相似文献   
5.
Drug design and discovery studies are important because of the prevalence of diseases without available medical cures. New anticancer agents are particularly urgent because of the high mortality rate associated with cancer. A series of mononuclear gold (III) and platinum (II) complexes based on boronated phenylalanine (BPA) were designed and synthesized using 4,4’-dimethyl-2,2’-dipyridyl (L1) or 1,10-phenanthroline-5,6-dion (L2) ligands to obtain promising anticancer drug candidates. Proton nuclear magnetic resonance, infrared, mass spectrometry, and elemental analyses were utilized for chemical characterizations. Cell viability, cancer cell colony formation, endothelial tube formation, and cytoskeleton staining assays were performed using A549 lung adenocarcinoma and human umbilical vein endothelial cells (HUVECs) to investigate preliminary pharmacological activities. L1-based platinum (II) complex (BPA-L1-Pt) was the most promising complex, and has similar activity with the approved chemotherapy drug cis-platinum. Half maximal inhibitory concentration values for BPA-L1-Pt were 9.15 µM on A549s and 16.61 µM on HUVECs; the values for cis-platinum were 5.24 µM on A549s and 23.14 µM on HUVECs. Consequently, further synthesis studies should be performed to boost the cancer cell selectivity feature of BPA by varying metal and ligand types.  相似文献   
6.
Aim:To investigate the clinical characteristics of patients with Peyronie's disease(PD)and diabetes mellitus(DM).Methods:During an 8-year period,a total of 307 men seen at our outpatient clinic were diagnosed with PD.Clinicalcharacteristics,penile deformities and the erectile status of patients with PD and DM together(n=102)were retro-spectively analyzed and compared to patients with PD alone with no risk factors for systemic vascular diseases(n=97).Results:The prevalence of PD among men with DM and sexual dysfunction was 10.7%.The mean ageof diabetic patients with PD was(55.9±8.9)years;in the no risk factor group it was(48.5±9.0)years(P<0.05).The median duration of DM was 5 years.The majority of diabetic patients with PD(56.0%)presented in the chronicphase(P<0.05),and they were more likely to have a severe penile deformity(>60°)than the no risk factor group(P<0.05).In the diabetic group,the most common presenting symptom was penile curvature(81.4 %),followedby a palpable nodule on the shaft of the penis(22.5%)and penile pain with erection(14.7 %).A total of 19.6 % ofpatients were not aware of their penile deformities in the diabetic group.Erectile function,provided by history and inresponse to intracavernosal injection and a stimulation test,was significantly diminished in patients with PD and DM(P<0.05).Conclusion:DM probably exaggerates the fibrotic process in PD.Diabetic patients with PD have ahigher risk of severe deformity and erectile dysfunction(ED).PD seems to be a silent consequence of DM andshould be actively sought in diabetic men.(Asian J Androl 2006 Jan;8:75-79)  相似文献   
7.
Background: Hypotension due to vasodilatation after spinal anesthesia (SA) may be harmful. Heart rate variability, an indirect measure of autonomic control, may predict hypotension.

Methods: One hundred patients were studied. Retrospectively, heart rate variability was analyzed in 30 patients, classified depending on the lowest systolic blood pressure (SBP) after SA. Seventy patients were studied prospectively, assigned to one of two groups by their low to high frequency ratio (LF/HF) before SA. Sensitivity and specificity of LF/HF for prediction of decrease of SBP greater 20% of baseline were tested.

Results: Retrospective analysis showed differences of LF/HF depending on the degree of hypotension after SA. Prospective analysis demonstrated significant differences of SBP after SA depending on baseline LF/HF (mean +/- SD): low LF/HF (1.3 +/- 0.7) = > SBP: 91 +/- 8% of baseline versus high LF/HF (5.5 +/- 2.4) = > SBP: 66 +/- 10% of baseline (P < 0.05). Baseline LF/HF as well as high frequency and proportional decrease of SBP after SA correlated significantly, in contrast to baseline hemodynamic parameters heart rate and SBP. A receiver operator curve characteristic analysis showed a sensitivity and specificity of LF/HF > 2.5 of 85% to predict SBP decrease of greater than 20% of baseline after SA.  相似文献   

8.
Placenta is an important source of leptin during pregnancy that contributes to the high plasma leptin levels in pregnant women. Leptin and its functional receptors are synthesized in trophoblast cells that, in turn, secrete gestational hormones supporting a paracrine or autocrine role for leptin in the endocrine activity of the placenta. In the present study we examined the effect of leptin on in vitro release of gestational hormones (human chorionic gonadotropin (hCG), human placental lactogen (hPL), progesterone, estrogens and testosterone) by human term placental cells in culture. Placentas at term were obtained immediately after delivery from mothers with uncomplicated pregnancies. Progesterone, hCG, hPL, estradiol, estrone, estriol and testosterone levels were measured by different assays in culture media of cells maintained in monolayer culture after incubation for 12, 24, 48 or 72 h with leptin or placebo. Incubation with leptin did not modify hCG, hPL, progesterone, estriol and estrone secretion for any of the doses and times assayed. However, leptin led to a dose-dependent decrease in estradiol release. This effect was observed when treatment with recombinant human leptin spanned from 12 to 72 h. At this time an increase in testosterone levels was observed in leptin-treated cells versus placebo. These results indicate that leptin can be considered a gestational hormone implied in the endocrine function of the placenta, with an important role in control of the production of steroid reproductive hormones in placental cells in vitro.  相似文献   
9.
Budesonide-containing Apulein ointment has been used for the treatment of 29 women suffering from vulvitis, pruritus vulvae caused by vaginal discharge, gestational inflamed hemorrhoid, hymenitis, and late postoperative suture inflammation. The ointment rapidly and completely controlled local infiltration and the accompanying subjective complaints. It did not cause local alteration, the consistency of the ointment met the requirements and it did not disturb the patients' making their toilet. According to the author's opinion the product is a potent antiphlogistic which proved to be a valuable adjuvant to target specific treatment of inflammatory processes of the external female genital organs and perianal regions.  相似文献   
10.
The present study evaluated99mTc(V) DMSA as an agent for the visualization of inflammatory lesions in comparison to99mTc(HI) DMSA and99mTc-HIG. All three radiopharmaceuticals were prepared with commercial kits.99mTc(V) DMSA was prepared at neutral pH by the addition of first bicarbonate and then pertechnetate to the kit contents. The labeling efficiency was 99% as determined by ITLC. Abscesses were induced by i.m. injection of 50 μl turpentine into the right thighs of 36 Swiss albino mice. Six days later 3.7 MBq of each radiopharmaceutical was i.v. administered to 12 mice. The mice were sacrificed at 1,3,6 and 24 h later. Scintigrams were obtained with a gamma camera. The abscesses were better visualized on scintigrams with99mTc(V) DMSA compared to99mTc(III) DMSA, starting at 1 h. The animals were dissected and the organs were removed, weighed and the radioactivity determined with a gamma counter. The abscess to other tissue ratios were higher with99mTc(V) DMSA than the other radiopharmaceuticals. The max. abscess/muscle ratios were 9.46 ± 3.20 (24 h), 4.19 ± 1.39 (6 h) and 5.98 ± 1.17 (24 h) and max. abscess/blood ratios were 6.22 ± 1.41, 4.09 ± 0.84 and 0.914 ± 0.351 all at 24 h for99mTc(V) DMSA,99mTc(III) DMSA and99mTc-HIG, respectively. Experimental arthritis was produced in 6 New Zealand white rabbits by intra-articular injection of ovalbumin. Four days later 37 MBq of99mTc(V) DMSA and99mTc-HIG were each i.v. administered to 3 rabbits. Scintigrams obtained at 1, 3, 6, and 24 h clearly demonstrated arthritic joints. ROFs over arthritic joints were compared to contralateral normal joints (A/C). The max. A/C ratios were 2.10 ± 0.31 (3 h) and 2.92 ± 0.99 (24 h) for99mTc(V) DMSA and99mTc-HIG, respectively. Our results indicated the feasibility of imaging inflammatory lesions with99mTc(V) DMSA.  相似文献   
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