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   2952篇
  免费   225篇
  国内免费   6篇
耳鼻咽喉   18篇
儿科学   152篇
妇产科学   103篇
基础医学   371篇
口腔科学   77篇
临床医学   324篇
内科学   548篇
皮肤病学   72篇
神经病学   313篇
特种医学   473篇
外科学   234篇
综合类   54篇
一般理论   1篇
预防医学   173篇
眼科学   14篇
药学   183篇
  1篇
肿瘤学   72篇
  2023年   14篇
  2021年   31篇
  2020年   24篇
  2019年   33篇
  2018年   38篇
  2017年   32篇
  2016年   41篇
  2015年   45篇
  2014年   66篇
  2013年   79篇
  2012年   81篇
  2011年   104篇
  2010年   78篇
  2009年   90篇
  2008年   92篇
  2007年   112篇
  2006年   98篇
  2005年   99篇
  2004年   68篇
  2003年   85篇
  2002年   73篇
  2001年   83篇
  2000年   66篇
  1999年   73篇
  1998年   100篇
  1997年   97篇
  1996年   95篇
  1995年   85篇
  1994年   46篇
  1993年   67篇
  1992年   48篇
  1991年   59篇
  1990年   71篇
  1989年   92篇
  1988年   76篇
  1987年   63篇
  1986年   82篇
  1985年   89篇
  1984年   54篇
  1983年   48篇
  1982年   41篇
  1981年   47篇
  1980年   47篇
  1979年   27篇
  1978年   35篇
  1977年   35篇
  1976年   33篇
  1975年   28篇
  1974年   17篇
  1972年   19篇
排序方式: 共有3183条查询结果,搜索用时 16 毫秒
1.
Although there are well-established clinical human milk banks in the United States, there are no milk banks specifically intended to foster research on human milk. The authors' goal was to establish a milk bank with a core data set to support exploratory and hypothesis-driven studies on human milk. Donations to the Cincinnati Children's Research Human Milk Bank are accepted within the context of ongoing, hypothesis-driven research or on an ad hoc basis. Donors must give informed consent, and scientists wishing to use the samples must have Institutional review board approval for their use. Development of more research human milk banks can potentially provide resources for multidisciplinary collaboration and advance the study of human milk and lactation.  相似文献   
2.
3.
Work therapy and return to work   总被引:2,自引:0,他引:2  
In summary, data were selected for 1 year on patients treated in the Work Tolerance Program at the Hand Rehabilitation Center in Philadelphia. The type of information obtained has been used to obtain a profile of the patient population in the Work Tolerance Program. Statistical analysis was used, not only to formulate patient demographics, but also to evaluate the length of treatment of patients in the Work Tolerance Program. This period averaged 6 weeks. The statistical analysis also revealed there was significant interaction between the type of injury and the patient's diagnosis, and the rate of return to work. The patients with injuries to bone and nerve required longer periods of treatment until they returned to work than did patients with injuries to soft tissue or combination injuries. Our statistical analysis revealed that in 1982, 75 per cent of the patients in the Work Tolerance Program returned to work to regular or modified jobs. The length of time from injury to return to work was 63 per cent longer for patients with Workers' Compensation coverage than for patients with private insurance coverage. Because the statistical analysis that 60 per cent of the patients treated in the Work Tolerance Program were Workers' Compensation insured, and 80 per cent of the patients treated in the Work Tolerance Program were secondarily referred, it should be recognized that all patients with severe hand injuries would benefit from an immediate referral to a Hand Rehabilitation Center of excellence to facilitate their therapeutic management and expedite their recovery from time of injury to return to work. This study was restricted to the analysis of length of treatment and rate of return to work. Future studies should study the effect of early referral and the application of specific treatments.  相似文献   
4.
Both cyproterone acetate (CPA) and the gonadotrophin-releasing hormone agonist (GnRHa) have been shown to be effective for the treatment of hirsutism. We wished to compare the effectiveness of CPA in two standard doses with GnRHa and add-back therapy and to compare the length of remission after these treatments. A total of 60 hirsute hyperandrogenic women was assigned to the following treatment groups: CPA 2 mg with 35 microg of ethinylestradiol for 21 days each month (Diane group), CPA 50 mg, days 5-15, and ethinylestradiol 50 microg, days 5-25, each month (CPA group) or Decapeptyl 3.75 mg i.m. every 28 days with the addition of conjugated oestrogen 0.625 mg, days 1-21, and medroxyprogesterone acetate 10 mg, days 12-21 (GnRHa group). Hirsutism was graded by the Ferriman-Gallwey-Lorenzo (FGL) index and anagen hair shaft diameters and serum luteinizing hormone (LH) and testosterone were assessed before and every 3 months during and after treatment. All women were treated for 1 year with 1 year follow-up. At baseline hirsutism and endocrine patterns were similar in all groups. After one year of treatment, hirsutism decreased in all groups but the changes were greater (P <0.05) in the CPA and GnRHa groups than in the Diane group. Serum LH and testosterone were lowest in the GnRHa group. After withdrawal, hirsutism increased rapidly in the Diane and CPA groups and after 6 months, FGL scores and hair shaft diameters were similar to pretreatment values. In the GnRHa group, hirsutism increased more gradually and after 1 year of withdrawal, FGL scores and hair diameters were significantly (P <0.05) less than pretreatment values. Serum LH and testosterone increased rapidly in all three groups reaching pretreatment values by 6 months. These data suggest equal efficacy of the GnRHa and the high dose CPA regimen for the treatment of hirsutism in hyperandrogenic women. GnRHa with add-back treatment appears to result in a longer remission of hirsutism in comparison with CPA.   相似文献   
5.
BACKGROUND: In general practice, acute sinusitis is frequently diagnosed and treated with antibiotics. OBJECTIVE: This study aimed to determine the evidence for the effectiveness of antibiotic treatment in acute maxillary sinusitis in adults by assessing the methodological quality of placebo-controlled double-blind randomized trials. METHOD: An evaluation by four raters through a 35-item scoring-scale for internal and external validity of all placebo-controlled double-blind randomized trials on acute sinusitis found between January 1966 and July 1996. RESULTS: Eighty-five trials were excluded because they were not placebo-controlled, double-blind, randomized, or were carried out in patients with chronic sinusitis or in children. The three remaining trials were performed in different populations (one in general practice) between 1973 and 1978. Only one study claimed superiority of antibiotic treatment. Different inclusion criteria and major outcome measures were used by the authors. The reliability of major outcome events was reported poorly or not at all and in two studies outcome measures were clinically inappropriate. The studies scored 30-62% of the maximum attainable score for internal validity and 10-20% for external validity. CONCLUSION: The effectiveness of antibiotic treatment in acute maxillary sinusitis in a general practice population is not based sufficiently on evidence.   相似文献   
6.
7.
8.
9.
Traumatic pseudoaneurysms of the superior mesenteric artery (SMA) are extremely rare. We describe two cases of posttraumatic proximal SMA pseudoaneurysms with symptoms of gastric outlet obstruction. Repair was accomplished by aorta-SMA bypass with saphenous vein. Injuries to the proximal SMA are easily missed at laparotomy, especially if intestinal ischemia or hematomas are absent. Recognition and repair are stressed to avoid the complications associated with pseudoaneurysm formation.  相似文献   
10.
BACKGROUND: There are obvious advantages to increasing donor retention. However, for reasons of blood safety, certain donors may, in fact, be more desirable to retain than others. “Safe” donors are defined as those who provided a blood donation that was negative on all laboratory screening tests and who subsequently reported no behavioral risks in response to an anonymous survey. This study identifies the most important factors affecting the intention of “safe” donors to provide another donation. STUDY DESIGN AND METHODS: An anonymous survey asking about donation history, sexual history, injecting drug use, and recent donation experience was mailed to 50,162 randomly selected allogeneic donors (including directed donors) who gave blood from April through July or from October through December 1993 at one of the five United States blood centers participating in the Retrovirus Epidemiology Donor Study. Before mailing, questionnaires were coded to designate donors with nonreactive laboratory screening tests at their most recent donation. RESULTS: A total of 34,726 donors (69%) responded, with substantially higher response among repeat donors. According to reported intentions only, the vast majority of “safe” donors indicated a high likelihood of donating again within the next 12 months. Only 3.4 percent reported a low likelihood of donating again. A comparison of those likely to return and those unlikely to return reveals significant differences in demographics and in ratings of the donation experience. A higher proportion of those unlikely to return were first-time donors, minority-group donors, and donors with less education. The highest projected loss among “safe” donors was seen for those who gave a fair to poor assessment of their treatment by blood center staff or of their physical well-being during or after donating. CONCLUSION: These data suggest that efforts to improve donors' perceptions of their donation experience, as well as attention to the physical effects of blood donation, may aid in the retention of both repeat and first-time donors.  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