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   576篇
  免费   38篇
耳鼻咽喉   7篇
儿科学   13篇
妇产科学   5篇
基础医学   50篇
口腔科学   24篇
临床医学   19篇
内科学   140篇
皮肤病学   2篇
神经病学   44篇
特种医学   3篇
外科学   107篇
综合类   4篇
一般理论   2篇
预防医学   15篇
眼科学   11篇
药学   29篇
中国医学   1篇
肿瘤学   138篇
  2023年   5篇
  2021年   13篇
  2020年   7篇
  2019年   11篇
  2018年   13篇
  2017年   8篇
  2016年   10篇
  2015年   13篇
  2014年   5篇
  2013年   15篇
  2012年   18篇
  2011年   17篇
  2010年   13篇
  2009年   8篇
  2008年   14篇
  2007年   14篇
  2006年   17篇
  2005年   30篇
  2004年   20篇
  2003年   13篇
  2002年   16篇
  2001年   10篇
  2000年   25篇
  1999年   16篇
  1997年   8篇
  1996年   5篇
  1995年   5篇
  1994年   5篇
  1992年   17篇
  1991年   13篇
  1990年   9篇
  1989年   10篇
  1988年   14篇
  1987年   28篇
  1986年   17篇
  1985年   20篇
  1984年   20篇
  1983年   12篇
  1982年   7篇
  1981年   9篇
  1979年   9篇
  1978年   4篇
  1976年   8篇
  1975年   8篇
  1974年   7篇
  1973年   9篇
  1972年   5篇
  1971年   7篇
  1969年   8篇
  1967年   4篇
排序方式: 共有614条查询结果,搜索用时 15 毫秒
71.
72.
Infection of the cornea with bacteria, viruses, or fungi can result in corneal ulceration. Corneal stromal cells participate in the immune and inflammatory responses to such infection in part by producing various cytokines and chemokines. The effects of lipopolysaccharide (LPS), polyinosinic-polycytidylic acid [poly(I:C)], and zymosan as surrogates for bacteria, viruses, and fungi, respectively, on the release of cytokines and chemokines from cultured human corneal fibroblasts were examined in order to identify common factors in infectious corneal keratitis. The secretion of various cytokines and chemokines by human corneal fibroblasts exposed to LPS, poly(I:C), or zymosan was measured with a multiplex assay system. LPS induced the release of interleukin (IL)-6, IL-8, MCP-1, RANTES, IP-10, eotaxin, and IL-12 from corneal fibroblasts. Poly(I:C) stimulated the secretion of IL-6, IL-8, MCP-1, RANTES, IP-10, eotaxin, MIP-1β, and interferon-γ, whereas zymosan triggered the production of IL-6, IL-8, and MCP-1. LPS, poly(I:C), and zymosan thus each induced a distinct pattern of cytokine and chemokine release from human corneal fibroblasts, with the release of IL-6, IL-8, and MCP-1 being commonly elicited by all three agents. Our results suggest that IL-6, IL-8, and MCP-1 may therefore play a key role in the inflammatory response to corneal infection.  相似文献   
73.
Six hundred thirty-two patients were referred to the Colorectal Clinic from February 1983 to February 1986 for screening with the Pentax 65 cm flexible sigmoidoscope. Forty-nine of these patients (8 percent) had adenomatous polyps. There were 27 males and 22 females. The mean distance examined by the 65 cm flexible sigmoidoscope was 55 cm. Five patients were excluded from analysis, leaving 44 patients who underwent colonoscopy to the cecum. At the time of colonoscopy, 15 of the 44 patients (34 percent) had one or more adenomatous polyps beyond reach of the 65 cm flexible sigmoidoscope. The remaining 29 patients who underwent colonoscopy had no polyps beyond reach of the 65 cm flexible sigmoidoscope. Thirty adenomatous polyps, one invasive carcinoma of the ascending colon, and one hyperplastic polyp were found in these 15 patients. In summary, 34 percent of patients found to have adenomatous polyps within reach of the 65 cm flexible sigmoidoscope harbored one or more adenomatous polyps in the proximal colon at the time of colonoscopy. A positive 65 cm flexible sigmoidoscope examination requires colonoscopy to identify and remove proximal premalignant lesions, thereby aborting the polyp-cancer sequence.  相似文献   
74.
75.
Routine preoperative intravenous pyelography was performed in a series of 105 consecutive male patients with rectal or rectosigmoid carcinomas who were totally free of urinary symptoms. Abnormal findings were present in 26 percent of those patients. Postoperative intravenous pyelograms were performed in 61 patients. Twenty-one percent of patients with negative preoperative intravenous pyelograms and 42 percent of patients with positive preoperative intravenous pyelograms had abnormal findings in the postoperative intravenous pyelograms. Preoperative cystoscopy was performed in 52 patients. Thirtyone percent of patients with negative preoperative intravenous pyelograms and 76 percent of patients with positive preoperative intravenous pyelograms had abnormal cystoscopic findings. The overwhelming majority of cystoscopic findings in patients with negative preoperative intravenous pyelograms were not related to the primary tumor. The findings of this prospective study suggest that routine preoperative intravenous pyelography is indicated in patients with rectosigmoid or rectal tumors without symptoms related to the urinary tract. Postoperative intravenous pyelography is indicated only in patients with positive preoperative intravenous pyelograms. Preoperative cystoscopy is indicated when the preoperative intravenous pyelogram is positive and especially if intravenous pyelography findings are suggestive of bladder-wall defect or extrinsic pressure.  相似文献   
76.
Summary A patient with malignant lymphoma showed severe hypophosphatemia during a blastic crisix. x-Ray microprobe analysis of the cells at this stage revealed a high phosphorus content. Following treatment and a decline in the white cell count the serum phosphorus increased, whereas the cellular phosphorus decreased. The potential prognostic value of serum and cellular phosphorus determinations during the course of malignant disorders of the hematopoietic system is discussed.  相似文献   
77.
The case history of a patient heavily infested with Plasmodium vivax is reported. Numerous peripheral red blood cells, containing trophozytes, permitted to observe the parasites with a transmission and scanning electron microscope.  相似文献   
78.
In recent years, there has been a growing interest in composite components, which may be designed to provide enhanced mechanical and physical effective properties. One of the methods available to produce such components is joining by plastic deformation, which results in metallurgical bonding at the interface. However, the portions of the interface that are bonded and the inhomogeneity in the bonding strength achieved at the interface tend to be overlooked. In the present study, Al6061 beams were bonded, by hot compression (300–500 °C) to different degrees of reduction. The compression was followed by tensile debonding experiments and the revealed interface was microscopically characterized in order to determine the areas that were metallurgically bonded. The SEM characterization revealed that the actual bonded area is much smaller than the interface contact area. Thermo-mechanical finite element models of the compression stage were used to investigate the thermo-mechanical fields, which develop along the interface and influence the resulting bonding strength. The principal strain field patterns across the interface area were shown to be similar to the experimentally observed temperature-dependent bonding patterns. In addition, a quantitative criterion for bonding quality was implemented and shown to correlate with the experimental findings.  相似文献   
79.
Background : We analyzed the results of conservative therapy for superficial bladder cancer to determine the risk factors for recurrence and progression.
Methods : Between May 1984 and February 1997, 111 patients with primary superficial bladder cancer were treated by a transurethral resection with or without intravesical instillation of chemotherapy, or for patients with concomitant carcinoma in situ (CIS), bacillus Calmette-Guerin. We examined the relationship between tumor stage, grade, incidence of concomitant CIS and recurrence-free survival according to pathologic findings and the drugs instilled.
Results : The incidence of concomitant CIS in pTI, grade 3 tumors was significantly higher than that in pTa, grade 1 tumors (42% vs. 3%, P= 0.006). The 5-year recurrence-free survival rate of all patients was 73%. There was no significant difference in recurrence-free survival and pathologic stage, tumor grade, presence of concomitant CIS, or drugs used for instillation. However, the recurrence-free survival in patients with 5 tumors was significantly lower than in patients with less than 5 tumors. Of the 111 patients, only 3 patients demonstrated disease progression and underwent a radical cystectomy, while 1 patient with a pTI b, grade 3 tumor developed a tumor in the ureter. No patient died of bladder cancer.
Conclusion : Our results indicate that the prognosis of superficial bladder cancer patients with a high-stage, high-grade (pTI, grade 3) tumor is favorable when treated by a transurethral resection and intravesical instillation. Bacillus Calmette-Guerin therapy is useful to prevent the recurrence of tumors with concomitant CIS.  相似文献   
80.
Fifteen patients with advanced, measurable renal cell carcinoma entered a Phase II clinical trial of interleukin-2 (IL-2) (Teceleukin, Hoffmann-La Roche Inc., Nutley, NJ) and interferon (IFN) (Roferon A, Hoffmann-La Roche Inc.). IL-2 was administered by continuous infusion daily for 4 days and IFN was administered by intramuscular injection daily for 4 days; therapy continued for 4 weeks. Eight men and seven women were treated in this trial (median age, 61 years). Toxicity was moderate to severe with fatigue, nausea, vomiting, hypotension, and elevated blood urea nitrogen bunion and creatinine levels seen in all patients. Two patients achieved a complete remission and two patients achieved a partial remission. The median duration of response was 18 months. IL-2 and IFN is an active combination in the treatment of renal cell carcinoma and warrants further investigation.  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