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   13883篇
  免费   754篇
  国内免费   219篇
耳鼻咽喉   153篇
儿科学   326篇
妇产科学   377篇
基础医学   1875篇
口腔科学   318篇
临床医学   1438篇
内科学   2833篇
皮肤病学   531篇
神经病学   844篇
特种医学   684篇
外科学   2225篇
综合类   176篇
现状与发展   1篇
一般理论   2篇
预防医学   590篇
眼科学   275篇
药学   1164篇
中国医学   151篇
肿瘤学   893篇
  2023年   91篇
  2022年   248篇
  2021年   422篇
  2020年   198篇
  2019年   270篇
  2018年   412篇
  2017年   295篇
  2016年   346篇
  2015年   443篇
  2014年   638篇
  2013年   660篇
  2012年   1043篇
  2011年   1019篇
  2010年   602篇
  2009年   485篇
  2008年   808篇
  2007年   882篇
  2006年   750篇
  2005年   745篇
  2004年   644篇
  2003年   520篇
  2002年   494篇
  2001年   433篇
  2000年   399篇
  1999年   311篇
  1998年   131篇
  1997年   113篇
  1996年   108篇
  1995年   72篇
  1994年   73篇
  1993年   50篇
  1992年   131篇
  1991年   125篇
  1990年   108篇
  1989年   76篇
  1988年   59篇
  1987年   68篇
  1986年   55篇
  1985年   53篇
  1984年   32篇
  1983年   24篇
  1980年   24篇
  1979年   32篇
  1977年   32篇
  1976年   24篇
  1975年   25篇
  1974年   28篇
  1973年   26篇
  1972年   30篇
  1970年   23篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
The protective effect of combined treatment (immunomodulation with Propionibacterium avidum KP-40; liver lectin blocking by D-galactose administration) on the liver colonization of RAW 117-H10 lymphosarcoma was investigated in BALB/c-mice. Both, immunomodulation with P. avidum KP-40 as well as liver lectin blocking by D-galactose treatment significantly decreased the number of liver tumor colonies in this experimental model. However, the combination of P. avidum KP-40 and D-galactose obviously proved to be superior to each monotherapy since the liver colonization by RAW 117-H 10 lymphosarcoma could be completely inhibited.  相似文献   
62.
63.
Exposure to toxic chemicals in the work, natural and home environments is recognised as combined exposure. The system of integral evaluation of human exposure should take account of all toxic substances occurring in all environmental media (air, water, soil and food), and all routes through which they enter the human body. To provide the integral evaluation it is necessary to develop different exposure scenarios based on dose intake or derived values. Following the toxicological criteria, calculated exposure indicators, after their standardisation and aggregation, should be converted into combined exposure indices. The index value will reflect the level of combined exposure.  相似文献   
64.
Shin CY  Lee WJ  Kim DJ  Park CS  Park SH  Ko KH 《Hybridoma》1999,18(5):457-463
The objective of this study was to generate and characterize monoclonal antibodies (MAbs) against human airway mucins, and therefore, should serve as a useful tool in studying the regulation of airway mucins in various physiological or pathological situations of human airway. As an antigen, we used a high molecular mass mucin preparation purified from the sputum of normal human subjects. Two monoclonal hybridomas, namely MAbs HM02 and HM03 were obtained and they showed strong immunoreactivity against purified or crude mucin in sputum or bronchial washing of normal human subject. With the high immunoreactivity of these MAbs, mucin contents could be analyzed with more than 100-fold dilution of human airway secretion. The antibodies recognized carbohydrate epitopes because their immunoreactivity was completely abolished by treatment of the mucin with 5 mM periodate. Further characterization of MAbs HM02 and HM03 showed that: (1) they belong to the IgM type; (2) they bind to high molecular mass mucins based on Western blot; (3) they could indirectly immunoprecipitate human airway mucin and as we know, this is the first to demonstrate immunoprecipitation of human airway mucin with anti-human mucin antibodies; and (4) they bind to the goblet cell in airway epithelium as well as some submucosal glands based on immunohistochemistry. Therefore, MAbs HM02 and HM03 should be able to serve as an invaluable tool in studying the regulation of airway mucins in various physiological and pathological situations of human airway.  相似文献   
65.
BACKGROUND: The renal allograft biopsy is generally accepted as the gold standard for clarifying the cause of renal dysfunction. However, the clinical usefulness of this procedure has rarely been studied prospectively, nor have most studies included follow-up of patients to delineate the influence of the biopsy on clinical outcome. In this study, we evaluated prospectively the clinical usefulness of the allograft biopsy in renal transplant recipients receiving cyclosporine (CyA). METHODS: During a 21-month period, 82 biopsies were performed. In 54 instances (47 patients), we outlined a presumed diagnosis and tentative treatment plan before the procedure. After the biopsy, a definitive diagnosis was made and an appropriate patient management approach was instituted. We analyzed the incidence of change in patient management that resulted from histological findings. All patients were followed to monitor their response to treatment and allograft survival. In cases of biopsy-proven acute cellular rejection (ACR) or cyclosporine (CyA) toxicity, clinical and laboratory data from the day of the biopsy were reviewed to determine their diagnostic value. RESULTS: One biopsy specimen was inadequate for definitive interpretation. The biopsy findings resulted in a change in patient management in 22 (41.5%) of the remaining 53 cases (change group). The incidence of altered patient management was 38.7% in biopsy specimens taken in the first month, 55.6% between 1 and 12 months, and 38.5% after 1 year posttransplantation. A change in management was required in 2 of 2 patients with chronic allograft dysfunction, in 44.4% of the 45 patients with acute allograft dysfunction, and in none of the patients with delayed graft function (n=6). Within the first week of treatment 19 of 22 (86.4%) in the change group and 25 of 31 (80.6%) in the no change group had a positive response to therapy. The 1-year allograft survival rate was also similar between the two groups. None of the clinical and laboratory data was useful in distinguishing ACR from CyA toxicity. CONCLUSIONS: Renal allograft biopsy findings alter patient management recommendations in approximately 40% of patients in whom a presumptive diagnosis had been made on the basis of clinical and laboratory findings. Patients who had a change in patient management because of biopsy findings demonstrated a response to therapy and allograft survival similar to those of patients who had no alteration in management plan after the biopsy.  相似文献   
66.
We designed a dorsal adipofascial pedicled flap to cover amputations of the tip of the same digit. This flap includes all the adipofascial tissues from the dermis to the paratenon of the extensor tendons. After elevation of the skin, the adipofascial tissues are raised as a flap and turned over to resurface the exposed bone or joint and then covered with a split thickness skin graft. Ten digital amputations between the distal phalanx proximal to the nail matrix and the mid portion of the middle phalanx were successfully resurfaced with dorsal adipofascial turn-over flaps. All flaps survived completely and the mean follow-up was 11 months. This one-step procedure would seem to be a relatively simple way of achieving early recovery because it does not require the use of distant flaps immobilization of adjacent digits, or homodigital flaps that might jeopardize an already injured finger.  相似文献   
67.
The distribution of sulfated proteoglycans (PGs) in the normal human trabecular meshwork was studied by histochemical electron microscopy using the cationic dye, cuprolinic blue (CB).. The trabecular meshwork was obtained from human enucleated eyes and incubated for three days. After incubation, they were stained with 0.2% CB at a critical electrolyte concentration and prepared for histochemical electron microscopy. Ultrastructurally, PG-CB complexes were found as small punctate or filamentous structures, and were associated with collagen fibrils in the cores of the trabecular beams and the basal laminae of trabecular endothelial cells. In addition, large filamentous PG-CB complexes were mainly associated with areas of amorphous extracellular matrix between the collagen fiber bundles and in the fine fibrillar material near the basal laminae of endothelial cells of Schlemm's canal. This investigation resulted in an illustration of the ultrastructural distribution of PGs in the human trabecular meshwork. Further studies will be needed to specify the nature of PGs and their role in the aqueous outflow system.  相似文献   
68.
BACKGROUND AND OBJECTIVE: Trachoma remains the leading cause of preventable corneal blindness. The outcome of penetrating keratoplasty (PK) in these patients is usually poor because of the extensive corneal vascularization, adnexal and ocular surface problems. We evaluated the long-term results of PK in patients with corneal scarring due to trachoma. PATIENTS AND METHODS: The fiels of 16 eyes of 13 patients who underwent PK due to late sequel of trachoma were reviewed. RESULTS: Preoperative visual acuity ranged from light perception to finger counting levels. Preoperatively, dry-eyes, meibomian gland dysfunction, trichiasis and cicatricial entropion were treated. Over a mean postoperative follow-up of 26.1 +/- 15.6 months (range of 14-61 months), eyes required redrafting due to graft rejection and failure, and corneal ulceration (12.5%). Fourteen eyes remained clear grafts (87.5%), and 13 eyes (81.3%) achieved 0.1 or better visual acuity. CONCLUSIONS: These results suggest that although patients with corneal scarring due to trachoma are at high risk, PK may be helpful for visual rehabilitation.  相似文献   
69.
Aggregation inhibitory activity of minor acetophenones from Paeonia species   总被引:4,自引:0,他引:4  
Lin HC  Ding HY  Ko FN  Teng CM  Wu YC 《Planta medica》1999,65(7):595-599
Two minor acetophenones, 2,5-dihydroxy-4-methoxy-acetophenone (2) and 2,5-dihydroxy-4-methylacetophenone (7) from Paeonia species were found to selectively inhibit the aggregation of rabbit platelets induced by arachidonic acid. They were more potent than the major compound, paeonol (1), and 7 also inhibited the formation of TXA2 and PGD2 from arachidonic acid.  相似文献   
70.
In many Western developed countries, the incidence of stomach cancer has declined dramatically. This decrease was an extraordinary, "unplanned triumph", especially when compared to other cancers. Stomach cancer is still the most prevalent malignant tumor in Korea. Most Koreans carry Helicobacter pylori in their stomach. Thus, a new hypothesis, based on the relationship between the host and Helicobacter pylori, is presented as the carcinogenesis of human stomach cancer. The reasons for why the N-nitrosamide hypothesis should be dismissed as the etiology of stomach cancer, and why the contemporarily available principles and practice of intervention strategies to rapidly decrease the surprisingly high prevalence rate of Helicobacter pylori infection are impractical at this moment, are explained. In order to introduce an alternative provisional strategy of the "planned triumph" for the population vulnerable to stomach cancer, vitamin C is defined as an anti-inflammatory agent on the basis of the pathogenesis of Helicobacter pylori infection.  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