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   1712篇
  免费   100篇
  国内免费   44篇
耳鼻咽喉   12篇
儿科学   67篇
妇产科学   14篇
基础医学   122篇
口腔科学   41篇
临床医学   189篇
内科学   341篇
皮肤病学   34篇
神经病学   46篇
特种医学   151篇
外科学   140篇
综合类   250篇
预防医学   118篇
眼科学   17篇
药学   165篇
中国医学   76篇
肿瘤学   73篇
  2022年   12篇
  2021年   27篇
  2020年   17篇
  2018年   14篇
  2017年   29篇
  2016年   18篇
  2015年   38篇
  2014年   55篇
  2013年   75篇
  2012年   80篇
  2011年   97篇
  2010年   89篇
  2009年   79篇
  2008年   100篇
  2007年   77篇
  2006年   53篇
  2005年   46篇
  2004年   31篇
  2003年   35篇
  2002年   33篇
  2001年   33篇
  2000年   20篇
  1999年   29篇
  1998年   31篇
  1997年   41篇
  1996年   28篇
  1995年   20篇
  1994年   16篇
  1993年   23篇
  1991年   21篇
  1990年   10篇
  1989年   19篇
  1988年   20篇
  1987年   18篇
  1986年   12篇
  1985年   20篇
  1984年   9篇
  1983年   10篇
  1982年   10篇
  1981年   14篇
  1978年   9篇
  1975年   9篇
  1959年   28篇
  1958年   72篇
  1957年   67篇
  1956年   58篇
  1955年   50篇
  1954年   42篇
  1949年   13篇
  1948年   17篇
排序方式: 共有1856条查询结果,搜索用时 15 毫秒
1.
An antiserum to the purified porcine outer acrosomal membrane (OAM) was raised in female Balb/c mice and was characterized by means of an indirect ELISA. The hyperimmune serum reacted selectively with the acrosomal cap of the sperm head and showed an extremely good cross reactivity with bull and human spermatozoa when assayed by indirect immunofluorescence. Immunoelectron microscopy using the protein A-gold method further confirmed the specificity of the anti-OAM-antiserum for the OAM. In an effort to identify the OAM antigens recognized by the hyperimmune serum and to analyse the extent of cross reactivity on a molecular level, the SDS-extractable proteins were separated by SDS-PAGE, transblotted and immunoprinted using an 125J-conjugated anti-mouse-antibody. To facilitate functional and structural analysis of distinct OAM-proteins monoclonal antibodies were generated by hybridization of mouse myeloma cells with the splenocytes of female Balb/c mice immunized with the purified OAM. One fusion resulted in about 100 anti-OAM-antibodies secreting hybridoma cultures, of which about 30% showed cross reaction with human and bull spermatozoa. Four stable cell lines were selected for this study secreting antibodies directed against the outer acrosomal membrane of boar spermatozoa. Whereas the polyclonal immune mouse serum stained the entire acrosomal cap, the four hybridoma antibodies generated a patch-work-like immunofluorescence pattern over the acrosome. HPLC-ELISA of the solubilized OAM revealed first information on the nature of the corresponding membrane antigen.  相似文献   
2.
BACKGROUND: Previous data indicate that injections of autologous fibroblasts increase collagen formation, accompanied by a concomitant increase in thickness and density of dermal collagen. OBJECTIVE: The purpose of this study was to determine efficacy and side effects of autologous living fibroblast injections versus placebo in a randomized Phase III trial for the treatment of various facial contour defects. METHODS: This was a double-blind, randomized comparison of injectable living autologous fibroblast cells and placebo for the treatment of facial contour defects (N=215). Live fibroblasts (20 million/mL) or placebo (the transport medium without living cells) were given as three doses administered at 1- to 2-week intervals. Efficacy evaluations were performed 1, 2, 4, 6, 9, and 12 months after the first injection. RESULTS: Living fibroblasts produced statistically significantly greater improvements in dermal deformities and acne scars than did placebo. The difference between live fibroblast injections and placebo achieved statistical significance at 6 months (p<.0001). At 9- and 12-month follow-up, live fibroblast-treated patients continued to demonstrate benefit from treatment with response rates of 75.0 and 81.6%, respectively. No serious treatment-related adverse events were reported. CONCLUSIONS: Our results indicate that autologous fibroblast injections can safely and effectively produce improvements in rhytids, acne scars, and other dermal defects continuing for at least 12 months after injection.  相似文献   
3.
Clinical Experience with Light-Emitting Diode (LED) Photomodulation   总被引:1,自引:0,他引:1  
Background. Light-emitting diode (LED) photomodulation is a novel nonthermal technology used to modulate cellular activity with light.
Objective:. We describe our experience over the last 2 years using 590 nm LED photomodulation within a dermatologic surgery environment.
Methods. Practical use of nonthermal light energy and emerging applications in 3,500 treatments delivered to 900 patients is detailed.
Results. LED photomodulation has been used alone for skin rejuvenation in over 300 patients but has been effective in augmentation of results in 600 patients receiving concomitant nonablative thermal and vascular treatments such as intense pulsed light, pulsed dye laser, KTP and infrared lasers, radiofrequency energy, and ablative lasers.
Conclusion:. LED photomodulation reverses signs of photoaging using a new nonthermal mechanism. The anti-inflammatory component of LED in combination with the cell regulatory component helps improve the outcome of other thermal-based rejuvenation treatments.  相似文献   
4.
In an open, randomized cross-over study in 124 patients, we compared the efficacy, safety and patient preference of oral and subcutaneous sum triptan in the acute treatment of migraine. Patients were treated for 3 attacks or 3 months and then crossed over. Primary clinical efficacy was defined as a reduction in headache severity on a four-point self-rating scale from severe (3) or moderate (2) to mild (1) or none (0), or mild (1) to none (0). Efficacy was evaluated 2 h after the administration of subcutaneous and 4h after the administration of oral sumatriptan. Subcutaneous sumatriptan was significantly more effective than oral sumatriptan in relieving headache (over all three attacks 78% vs 61% improvement), improving clinical disability (55% vs 41 % improvement) and relieving nausea (69% vs 53%), vomiting (72% vs 32%) and phono- or photophobia (67% vs 49%). Median time to recurrence was shorter after subcutaneous (12.5 h) than after oral sumatriptan (18 h); the number of patients experiencing a recurrence was similar Patients reported more adverse events after subcutaneous sumatriptan (1.32 per attack) than after the oral form (0.85 per attack), but all adverse events were mild to moderate in intensity and of short duration. Patient opinion was more often positive after subcutaneous sumatriptan. These results may be useful in counselling patients to choose between the available marketed formulations of sumatriptan.  相似文献   
5.
6.
目的:制备分散性良好的超细β-磷酸三钙(β-TCP)/聚-L-乳酸(PLLA)复合材料及新型可吸收骨折内固定器。方法:通过研磨方法制备β-TCP超细粒子,用一缩二乙二醇作分散剂研磨β-TCP后,再将β-TCP与PLLA超声混合,制得复合材料,经注塑加工制成可吸收骨钉,并采用扫描电镜等方法进行表征。结果与结论:用一缩二乙二醇作分散剂研磨β-TCP后再经超声混合,可以使β-TCP超细粒子在复合材料中分散均匀,粒子大小仅为300nm左右,β-TCP与PLlA基体之间结合良好。超细β-TCP/PLLA复合材料可加工成可吸收骨钉,弯曲强度达到100MPa左右,完全满足松质骨内固定的要求。  相似文献   
7.
BACKGROUND: Pemphigus vulgaris (PV) is a severe blistering disease involving the skin and mucous membranes. The most common causes of death in these patients are adverse effects of drugs, and infection. Skin lesions are one of the important sources of infection. Thus, any local treatment that could reduce healing time of lesions and consequently reduce the total dosage of drugs needed to treat is favourable. OBJECTIVE: To evaluate the efficacy of epidermal growth factor (EGF) in reducing healing time of lesions in patients with pemphigus vulgaris. METHODS: In this randomized, double-blind, within-patient, left/right, controlled trial, 20 hospitalized patients with pathologial and immunohistologial (direct and indirect immunoflourecence) proven pemphigus vulgaris (PV) were chosen. In addition, all patients had at least one appropriate pemphigus lesion on each side of the body that had not healed after 2-week systemic therapy and sterile saline washing. EGF (10 microg/g) in 0.1% silver sulfadiazine cream vs. 0.1% silver sulfadiazine cream alone was applied randomly on one side of the body. RESULTS: Kaplan-Meier survival analysis suggested that median time to heal with application of EGF plus silver sulfadiazine cream was 9 days, in comparison with 15 days for silver sulfadiazine cream alone (log-rank test, P=0.0003). No intervention-related adverse effect was observed during the study. CONCLUSIONS: EGF can significantly reduce healing time of skin lesions in patients with pemphigus vulgaris, at least when this cream base is applied (Cochrane skin group identifier: CSG20).  相似文献   
8.
9.
10.
This article presents baseline data on the opinion toward alcoholbeverage warning labels and on levels of knowledge of the risksdiscussed in the contents of the labels prior to the labels'introduction, and on levels of knowledge of additional alcohol-relatedhazards not included in the proposed warning labels, among asample of 3065 adolescents of four religions living in the northernregion of Israel. About 2220 Arab participants (Moslems, Christiansand Druze) and 845 Jewish respondents answered in the winterof 1996 a Hebrew version of an American questionnaire, whichhad been used to measure levels of knowledge of the label inthe United States. More respondents were in favour of warninglabels on alcohol containers than on advertisements. Arabs asa group were more in favour of warning labels on alcohol containersthan Jews. The initial knowledge levels among the participantswere not very high, especially concerning the item ‘Drinkingimpairs ability to operate machinery’ (74.4%) which isincluded on the proposed warning label, and concerning two hazardswhich are not included: ‘Drinking increases risk of cancer’(54.6%) and ‘Drinking increases risk of high blood pressure’(60.4%). Abstainers knew more than drinkers that ‘Pregnantwomen should not drink’, ‘Drinking increases riskof cancer’ and ‘Alcohol in combination with otherdrugs is hazardous’. Implications for public health arediscussed and alternative warning messages that might be usedto inform the Israeli public of several less well-known hazardsare suggested.  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