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   53098篇
  免费   3273篇
  国内免费   315篇
耳鼻咽喉   563篇
儿科学   1499篇
妇产科学   1298篇
基础医学   5633篇
口腔科学   1843篇
临床医学   4820篇
内科学   11479篇
皮肤病学   1027篇
神经病学   3197篇
特种医学   1681篇
外国民族医学   8篇
外科学   8885篇
综合类   1285篇
现状与发展   3篇
一般理论   44篇
预防医学   3792篇
眼科学   1940篇
药学   4353篇
  1篇
中国医学   444篇
肿瘤学   2891篇
  2024年   65篇
  2023年   630篇
  2022年   1619篇
  2021年   2549篇
  2020年   1599篇
  2019年   2004篇
  2018年   2438篇
  2017年   1767篇
  2016年   1885篇
  2015年   2002篇
  2014年   2556篇
  2013年   3069篇
  2012年   4499篇
  2011年   4439篇
  2010年   2519篇
  2009年   2102篇
  2008年   3178篇
  2007年   3128篇
  2006年   2737篇
  2005年   2412篇
  2004年   2129篇
  2003年   1781篇
  2002年   1546篇
  2001年   421篇
  2000年   372篇
  1999年   342篇
  1998年   247篇
  1997年   176篇
  1996年   187篇
  1995年   141篇
  1994年   113篇
  1993年   110篇
  1992年   172篇
  1991年   176篇
  1990年   147篇
  1989年   144篇
  1988年   121篇
  1987年   108篇
  1986年   101篇
  1985年   129篇
  1984年   95篇
  1983年   69篇
  1982年   70篇
  1981年   65篇
  1980年   53篇
  1979年   63篇
  1978年   50篇
  1976年   44篇
  1974年   43篇
  1973年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
PURPOSE: A 10-year retrospective study was undertaken of all patients treated for facial gunshot and shrapnel wounds at our medical center to evaluate the outcomes and assess the results of simultaneous management to treat the hard and soft tissue injuries primarily. PATIENTS AND METHODS: A total of 44 patients were treated. Medical documentation of the patients was compiled. All maxillofacial gunshot, shrapnel, and warfare injuries were treated by the oral and maxillofacial surgeon. Other concomitant bodily injuries were treated by pertinent consultant specialists. Patients ranged in age from 8 to 53 years, with a mean age of 24.7 years. Maxillofacial hard and soft tissue injuries were treated definitively in the first operation except when gross contamination, infection, extensive comminution, or general condition precluded this. RESULTS: There were 2 shotgun, 28 bullet, 10 shrapnel, 3 land mine, and 1 breech block injuries. Overall postadmission mortality in this series was 2.2%. Of the 97.7% of the patients who had an injury to the underlying craniofacial skeleton, all required surgical intervention. The soft tissue and underlying bony injuries were addressed concomitantly (in a single stage at the time of primary surgical debridement) in 86.3% of the patients. Nine percent of the patients had a tracheostomy emergently for management of the airway, 6.8% had an intracranial injury, and 2.2% of them required neurosurgery. In the series, 4.5% of the patients had neck wounds that required exploration. Comprehensive treatment was rendered in 1 to 3 major operations (average, 1.5). CONCLUSION: All patients in this series required surgical intervention for treatment of their facial gunshot wounds. Primary treatment of hard and soft tissue injuries of the face at the time of surgical debridement was possible in the majority of our patients. This minimized the number of admissions and did not bear a higher complication rate than other reported series that advocate multiple staged operations to treat such injuries despite the fact that, in our series, flaps were also mobilized for wound closure in the primary phase.  相似文献   
83.
Objective: To find out the spectrum of various histopathologic types of primary neoplasms of different parts of the gastrointestinal tract (oesophagus, stomach, small intestine, colorectum, anal canal) seen at the Kathmandu University Teaching Hospital (KUTH), Dhulikhel as there exists a worldwide wide variation in the distribution of various neoplasms of different parts of the gastrointestinal tract, which appears largely due to exogenous factors rather than due to inherent differences between populations. Materials and methods: This was a retrospective study. It was carried out at Kathmandu University Teaching Hospital (KUTH), Dhulikhel, Kavre, Nepal. All neoplasms of the gastrointestinal tract seen at the KUTH during the period 1st January 2004 to 31st December 2004 were included in this study and examined by light microscope (LM). Results: A total number of 18 cases of neoplasms of the gastrointestinal tract were seen. Out of these, 3 (16.7%) were of the oesophagus (all squamous cell carcinoma), 10 (55.5%) were of the stomach (six intestinal type and four diffuse type), 2 (11.1%) were of the small intestine (one was lymphoma of the mucosa associated lymphoid tissue - MALTOMA and other was a malignant gastrointestinal stromal tumour - GIST), 3 (16.7%) were of the colorectum (all adenocarcinoma), and none was of the anal canal. Conclusion: Relatively large number of cases of the carcinoma of the stomach were found in our this small series of the cases of the gastrointestinal tract in comparison to the Western countries. Key words: Neoplasms, gastrointestinal tract, gastric carcinoma intestinal type, gastric carcinoma diffuse type, Kathmandu University Teaching Hospital (KUTH).  相似文献   
84.
AIM: To evaluate the effects of oral continuous 17beta-estradiol plus norethisterone acetate (E2/NETA) replacement therapy on abdominal subcutaneous fat, serum leptin level (SLL) and body composition in postmenopausal women. MATERIALS AND METHODS: A 6-month, prospective, randomized, double-blind and placebo-controlled study was conducted. Forty-three healthy naturally postmenopausal women aged 43-65 years were randomly assigned to receive E2/NETA (2 mg E2 plus 1 mg NETA, n = 22) or placebo (n = 21). Fasting SLL by enzyme-linked immunosorbent assay, subcutaneous abdominal fat thickness (STh) by ultrasound and the anthropometric indices of body weight (BW), body mass index (BMI), waist and hip circumference (WC, HC) and waist-to-hip ratio (WHR) were recorded at the beginning and the end of the study. RESULTS: After 6 months of therapy, BW and SLL increased in the placebo group (p = 0.043 and 0.033, respectively). WC, HC and STh decreased significantly in the E2/NETA group (p = 0.002, 0.006 and 0.000, respectively) and they were also significantly lower in women receiving E2/NETA than in women taking placebo (p = 0.000, 0.034 and 0.000, respectively). At baseline, SLL and STh were positively correlated with all anthropometric indices except WHR. CONCLUSION: Oral continuous combined regimen of E2/NETA significantly reduced central fat accumulation as assessed by WC and STh, and attenuated the increase in SLL. The observed changes in SLL were highly and positively related to changes in STh. The oral continuous combined E2/NETA regimen appears to have protective effects on cardiovascular function and probably on metabolic diseases by its slimming effect upon WC in postmenopausal women.  相似文献   
85.
86.
87.
The effects and the mechanism of natural honey on absolute ethanol-induced gastric lesions were studied in rats. Drugs and/or honey were administered subcutaneously or orally to 48-h fasted animals at different time intervals before oral administration of ethanol (0.5 ml/100 g). Mucosal damage and pH were measured 1 h later. Honey afforded protection against gastric damage and reversed the changes in pH induced by ethanol. The effects of honey were dose- and time-dependent. Thus, pretreatment with honey (1.25 g/kg) 30 min before ethanol provided more than 80% protection. On the other hand, administration of honey simultaneously with or 5 min after ethanol failed to offer protection. The cyclooxygenase inhibitor indomethacin (IND) did not alter the protective effects when given before or after honey. The protective effects of honey could be reversed by treatment with the sulfhydryl (SH) blocker N-ethylmaleimide (NEM). Combined IND and NEM treatment caused greater reduction of the protective effects, but the values were not significantly different from those obtained with NEM alone. Thus, the gastroprotective effects of honey appeared to be mediated through SH-sensitive processes. Furthermore, the protective effects were supported by both macroscopic and microscopic findings. It is suggested that honey may be used clinically in preventing/reducing ethanol-induced gastric lesions in humans.  相似文献   
88.
Summary The excretion of thioethers was determined in the urine of workers involved in road paving operations and in the preparation of asphalt mixing in an asphalt plant. An occupationally nonexposed group served as control. From the results it was observed that there was no significant difference in urinary thioether levels between the exposed and nonexposed groups, however, smokers of both exposed groups had significantly higher urinary thioether levels than the nonexposed smoking workers. These results suggested that higher urinary thioether excretion could be only due to a difference in smoking behaviour. There were also significant differences in urinary thioether levels between the exposed smoking and nonsmoking workers. The authors suggest that these workers have a low mutagenic/carcinogenic risk and smoking is responsible for the majority of thioether excretion, as has been found by other investigators.  相似文献   
89.
1. The effects of graded doses of the α2-adrenoceptor agonists clonidine, tizanidine and BHT-920, and the α2-adrenoceptor antagonists yohimbine and idazoxan, on gastrointestinal transit were investigated in mice using the charcoal meal test. 2. The agonists produced significant and dose-dependent decreases in gastrointestinal transit, and the antagonists produced the opposite effect. In affecting the gastrointestinal transit, clonidine (1 mg/kg) was as effective as tizanidine (12 mg/kg) and BHT-920 (40 mg/kg), while yohimbine (2 mg/kg) was as effective as idazoxan (1 mg/kg). 3. Morphine (2, 4 and 8 mg/kg) significantly inhibited gastrointestinal transit. This effect was significantly reversed by the co-administration of yohimbine (2 mg/kg) and idazoxan (1 mg/kg). 4. The acute administration of glucose (5.04 g/kg, i.p.) potentiated the inhibition of gastrointestinal transit produced by clonidine (1 mg/kg) and BHT-920 (40 mg/kg). Glucose treatment, however, had no significant effect on the increase in gastrointestinal transit induced by yohimbine (2 mg/kg) or idazoxan (1 mg/kg). 5. Castor oil (0.25 mL/mouse, orally) induced diarrhoea in saline-treated animals within about 45 min. Clonidine (1 mg/kg), tizanidine (12 mg/kg) and BHT-920 (40 mg/kg) delayed the occurrence of diarrhoea to 2.1, 1.2 and 1.4 h, respectively.  相似文献   
90.
The authors present the results of a transmission electron-microscopic study performed on a tissue sample obtained by an intraocular fine-needle aspiration biopsy in a case of retinoma. The ultrastructural study showed that the tumor was composed mainly of granular osmiophilic material which contained some tumor cells. These cells showed peculiar ultrastructural characteristics, which demonstrated their neural character, and appeared in different degenerative stages. Apparently, this is the first case in whom ultrastructural technique have been applied to study an intraocular tumor sample obtained by intraocular fine-needle aspiration biopsy, and the first case of retinoma studied by such a diagnostic approach.  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