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   5080篇
  免费   358篇
  国内免费   10篇
耳鼻咽喉   81篇
儿科学   159篇
妇产科学   125篇
基础医学   913篇
口腔科学   37篇
临床医学   409篇
内科学   974篇
皮肤病学   102篇
神经病学   612篇
特种医学   166篇
外科学   523篇
综合类   21篇
一般理论   1篇
预防医学   432篇
眼科学   146篇
药学   315篇
中国医学   10篇
肿瘤学   422篇
  2023年   31篇
  2022年   45篇
  2021年   110篇
  2020年   85篇
  2019年   90篇
  2018年   113篇
  2017年   81篇
  2016年   119篇
  2015年   120篇
  2014年   157篇
  2013年   188篇
  2012年   304篇
  2011年   324篇
  2010年   231篇
  2009年   194篇
  2008年   302篇
  2007年   282篇
  2006年   342篇
  2005年   284篇
  2004年   262篇
  2003年   233篇
  2002年   223篇
  2001年   90篇
  2000年   84篇
  1999年   85篇
  1998年   60篇
  1997年   64篇
  1996年   35篇
  1995年   45篇
  1994年   31篇
  1993年   30篇
  1992年   50篇
  1991年   53篇
  1990年   53篇
  1989年   71篇
  1988年   40篇
  1987年   46篇
  1986年   38篇
  1985年   33篇
  1984年   49篇
  1983年   24篇
  1982年   18篇
  1980年   24篇
  1979年   34篇
  1978年   18篇
  1977年   23篇
  1975年   20篇
  1974年   20篇
  1973年   17篇
  1969年   19篇
排序方式: 共有5448条查询结果,搜索用时 15 毫秒
1.
BACKGROUND The adenoma detection rate(ADR) is inversely associated with the incidence of interval colorectal cancer and serves as a benchmark quality criterion during screening colonoscopy. However, adenoma miss rates reach up to 26% and studies have shown that a second inspection of the right colon in retroflected view(RFV) can increase ADR.AIM To assess whether inspection of the whole colon in RFV compared to standard forward view(SFV) can increase ADR.METHODS Patients presenting for screening or surveillance colonoscopy were invited to participate in this randomized controlled trial and randomized into two arms. In RFV arm colonoscopy was initially performed with SFV, followed by a second inspection of the whole colon in RFV. In the SFV arm first withdrawal was performed with SFV, followed by a second inspection of the whole colon again with SFV. Number, size and morphology of polyps found during first and second inspection in each colonic segment were recorded and all polyps were removed and sent for histopathology in separate containers.RESULTS Two hundred and five patients were randomly assigned to the RFV(n = 101) and SFV(n = 104) arm. In the RFV arm, both polyp detection rate(PDR) and ADR were increased under second inspection in RFV(PDR 1~(st) SFV: 39.8%, PDR 2~(nd)RFV: 46.6%; ADR 1~(st) SFV: 35.2%, ADR 2~(nd) RFV: 42%). Likewise, in the SFV arm,PDR and ADR were increased under second inspection(PDR 1~(st) SFV: 37.5%, PDR 2~(nd) SFV: 46.6%; ADR 1~(st) SFV: 34.1%, ADR 2~(nd)SFV: 44.3%) with no significant differences in ADR and PDR between the SFV and RFV arm. Mean number of adenomas per patient(APP) was increased in the RFV and SFV(APP RFV arm: 1~(st) SFV: 1.71; 2~(nd) RFV: 2.38; APP SFV arm: 1~(st) SFV: 1.83, 2~(nd)SFV:2.2). The majority of adenomas additionally found during second inspection in RFV or in SFV were located in the transverse and left-sided colon and were 5 mm in size.CONCLUSION Second inspection of the whole colon leads to increased adenoma detection with no differences between SFV and RFV. Hence, increased detection is most likely a feature of the second inspection itself but not of the inspection mode.  相似文献   
2.
3.
This report describes a young high-myopic patient who developed rubeosis iridis with peripheral retinal neovascularization one year after a circular buckling operation. Subsequently, vitreous bleeding and exudation led to traction retinal detachment which was treated successfully by anterior vitrectomy and cryopexy. It is suggested that this case represents a mild form of anterior-segment ischemia, combined with peripheral retinal ischemia.  相似文献   
4.
A 31-year-old married man with normal male characteristics requested hormonal treatment to enlarge his breasts and nipples. He did not feel himself to be homosexual or transsexual but considered himself incomplete without female breasts and nipples. Petting of his nipples resulted in sexual excitement and he presumed that feminization of his breasts would improve this function. His wife supported his wish. After treatment with 0.150 mg ethinylestradiol per day for 9 months, moderate breast enlargement occurred and the nipples became the size of normal female nipples. One year afterwards he remained satisfied with his female-type breasts and in particular with the increased sexual function of his nipples. Stimulation of his nipples resulted in erection and ejaculation.  相似文献   
5.
The determination of penetration pathways of topically applied substances into the skin is the subject of several investigations. Recently, follicular penetration has become a major focus of interest. To date, a direct, non-invasive quantification of the amount of topically applied substance penetrated into the follicles had not been possible. The development of such a method was the aim of this study. Therefore, the advantages of both stripping techniques, tape stripping and cyanoacrylate skin surface biopsy, were combined and evaluated. Tape stripping was used to remove the part of the stratum corneum that contained the topically applied dye. Subsequently, the follicular contents were ripped off by cyanoacrylate skin surface biopsy. The combined method termed "differential stripping" was evaluated in vitro and in vivo , and the amount of topically applied fluorescent dye penetrated into the hair follicles was quantified after different penetration times. After 30 min, 5% of the recovered concentration of sodium fluorescein was found in the follicular infundibula, where it was still detectable after 48 h. Altogether, the results of this investigation revealed that differential stripping is a new method that can be used to study the penetration of topically applied substances into the follicular infundibula non-invasively and selectively.  相似文献   
6.
7.
Fifty-nine patients with hyperlipoproteinaemia Type IIa and IIb who had failed to respond to 1-month's dietary therapy were treated over a 4-month period with either bezafibrate (600 mg/day) or gemfibrozil (1200 mg/day) in addition to their diet. Fasting serum lipid (cholesterol, HDL-cholesterol and triglycerides) and blood glucose levels were measured on entry and at monthly intervals, and routine laboratory investigations were carried out before and after treatment to monitor hepatic, renal and haematic tolerance. The results showed that whilst both drugs produced significant reductions from baseline in total cholesterol, LDL-cholesterol and triglyceride levels from Day 30 onwards, the reductions were more marked in the bezafibrate group. There was a trend for HDL-cholesterol levels to increase. Fasting blood glucose levels decreased significantly in the bezafibrate group and to a greater extent than in patients on gemfibrozil. Only 1 patient on bezafibrate did not tolerate bezafibrate whereas 13 patients on gemfibrozil reported side-effects, mainly gastro-intestinal, and 4 had to withdraw from the study during the first or second month.  相似文献   
8.
BACKGROUND: The purpose of this study was to describe the health status and work limitations in injured workers with musculoskeletal disorders at 1 month post-injury, stratified by return-to-work status, and to document their return-to-work trajectories 6 months post-injury. METHODS: A sample of 632 workers with a back or upper extremity musculoskeletal disorder, who filed a Workplace Safety and Insurance Board lost-time claim injury, participated in this prospective study. Participants were assessed at baseline (1 month post-injury) and at 6 months follow-up. RESULTS: One month post-injury, poor physical health, high levels of depressive symptoms and high work limitations are prevalent in workers, including in those with a sustained first return to work. Workers with a sustained first return to work report a better health status and fewer work limitations than those who experienced a recurrence of work absence or who never returned to work. Six months post-injury, the rate of recurrence of work absence in the trajectories of injured workers who have made at least one return to work attempt is high (38%), including the rate for workers with an initial sustained first return to work (27%). CONCLUSIONS: There are return-to-work status specific health outcomes in injured workers. A sustained first return to work is not equivalent to a complete recovery from musculoskeletal disorders.  相似文献   
9.
Introduction and background A 3-year-old Bosnian girl with a large symptomatic brainstem and multiple supratentorial cavernous angiomas, who underwent neurosurgical treatment, is presented. As multiple cavernomas are more common in familial cases, genetic analyses and neuroradiological imaging were performed in the patient and her parents to see whether there was any evidence for inheritance. This information is important for genetic counseling and provision of medical care for at-risk relatives. Currently, no recommendation is available on how to manage these cases.Results Genetic analyses demonstrated a novel CCM1 frameshift mutation (c.1683_1684insA; p.V562SfsX6) in the child and the asymptomatic 27-year-old mother. Sensitive gradient-echo magnetic resonance imaging of the mother revealed multiple supratentorial lesions, whereas analogous imaging of the father showed no pathological findings.Conclusion This case exemplifies that seemingly sporadic cases with multiple lesions might well be hereditary and that presymptomatic genetic testing of family members may identify relatives for whom clinical and neuroradiological monitoring is indicated.  相似文献   
10.
We report about the diagnostic and therapeutic approaches in 62 cases of Klatskin tumors operated during the last 5 years. In most patients the definite treatment consisted either of primary endoscopic drainage of the bile ducts or of a secondary endoscopic drainage after explorative laparotomy. Only one third of the patients could be operated in curative intention. Operative procedures included local tumor resections as well as a central bile duct resection combined with hemihepatectomy. The main problem in these operations is to avoid a biliodigestive anastomosis with tumor infiltrated bile ducts, because these patients would have been better treated endoscopically. After extended preoperative diagnostic procedures including CT-scan, ultrasound, ERCP and angiography in most cases the criteria for irresectability can be defined and unnecessary operative interventions can be avoided.  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