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   1488250篇
  免费   99982篇
  国内免费   3243篇
耳鼻咽喉   21806篇
儿科学   44732篇
妇产科学   42119篇
基础医学   208770篇
口腔科学   44936篇
临床医学   121285篇
内科学   295730篇
皮肤病学   34421篇
神经病学   118545篇
特种医学   57330篇
外国民族医学   436篇
外科学   225950篇
综合类   31749篇
现状与发展   6篇
一般理论   459篇
预防医学   110712篇
眼科学   35390篇
药学   111873篇
  4篇
中国医学   3591篇
肿瘤学   81631篇
  2018年   16424篇
  2017年   12461篇
  2016年   13441篇
  2015年   15046篇
  2014年   20173篇
  2013年   30641篇
  2012年   42415篇
  2011年   44850篇
  2010年   25638篇
  2009年   23776篇
  2008年   41716篇
  2007年   45431篇
  2006年   45631篇
  2005年   44070篇
  2004年   42553篇
  2003年   41082篇
  2002年   40222篇
  2001年   67975篇
  2000年   70236篇
  1999年   59152篇
  1998年   15288篇
  1997年   13872篇
  1996年   13335篇
  1995年   12580篇
  1992年   44791篇
  1991年   43062篇
  1990年   42350篇
  1989年   41079篇
  1988年   38423篇
  1987年   37781篇
  1986年   36310篇
  1985年   34428篇
  1984年   25770篇
  1983年   21864篇
  1982年   13085篇
  1981年   11940篇
  1979年   25047篇
  1978年   17806篇
  1977年   15538篇
  1976年   14039篇
  1975年   16065篇
  1974年   19106篇
  1973年   18631篇
  1972年   17846篇
  1971年   16703篇
  1970年   15837篇
  1969年   15335篇
  1968年   14468篇
  1967年   12921篇
  1966年   12063篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Hepatic encephalopathy is a reversible state of altered cognition that may occur in patients with acute or chronic liver disease or porto-systemic shunt, and in which known neurological or psychiatric signs may develop. Nitrogenated substances from intestinal digestion reach the brain without being cleared by their passage through the liver due to the presence of porto-systemic shunt. We report two cases of patients with porto-systemic shunt diagnosed with recurrent chronic hepatic encephalopathy refractory to conventional medical treatment. They were satisfactorily treated with shunt embolization using interventionist radiology techniques.  相似文献   
992.
993.
In Australia there is currently no consistent approach to collecting breast cancer specific data. The National Health Data Dictionary (NHDD) recommends a core set of generic data items for clinical cancer registration. However this list does not include the more detailed items required by specific tumour streams. The NBCC has developed a supplementary set of Breast Specific Data Items and definitions to serve as a guide for specialist breast cancer data collection in Australia. A multidisciplinary Working Group comprising clinical and consumer representation, including three breast surgeons, identified 16 breast specific data items for collection. The items are designed to align with items collected through the RACS National Breast Cancer Audit and leading cancer centres. A range of items from patient data (menopausal status), diagnostic data (HER2 status, sentinel lymph node), treatment (surgical margin clearance and involvement), and breast reconstruction are included. The data items are recommended as best practice for breast cancer specific data collection and aim to facilitate national consistency in defining, recording, and monitoring information about patients with breast cancer. This national approach will contribute to improved patient outcomes by informing planning, quality improvement and evaluation strategies for cancer services. The items are currently being piloted in two sites in NSW and will be available nationally in late 2007.  相似文献   
994.
Exercise advice is a well established component of the conservative management of intermittent claudication. Supervised programmes of exercise remain relatively uncommon and are provided mainly in secondary care. This review outlines the evidence for the effectiveness of different exercise regimens and the relative benefits of exercise therapy, where comparisons have been made with medical therapy, angioplasty and surgery.  相似文献   
995.
Intramedullary implants have decisive advantages in the treatment of femoral fractures in the vicinity of the hip joint: a torque that leads to a less pronounced varus position, implantation in the course of the relevant forces, and primary stability in the case of both stable and unstable fractures. Because of the constant developments in the implants available and the frequent failure to differentiate between stable and unstable fractures, some of the recommendations in the literature seem to contradict each other. However, precise analysis of the literature data show that stable fractures can be adequately treated with any technique, while unstable fractures fall in the domain of nailing systems. Since it is not possible to distinguish unequivocally between stable and unstable fractures, all trochanteric and subtrochanteric femoral fractures should be treated with a cephalomedullary nailing system.  相似文献   
996.
Deceased donor factors associated with poor graft outcome are well known, but how often these factors lead to livers left untransplanted is poorly defined. A nested, case-control study was conducted using the United Network for Organ Sharing (UNOS) database from 1987 to 2005. Only those donating >/=1 solid organ were included. Primary outcome was livers not transplanted (LNT, cases) versus transplanted (LT, controls). Primary variables for multivariate analysis were donor age and obesity. Covariates included donation after cardiac death (DCD), cerebral vascular accident death, viral serologies, cancer, ALT and bilirubin. There were 23 373 (26%) LNT's from 91 362 donors who donated at least one organ. Percent LNT fell over time (1987-1990: 48%; 1991-1995: 29%; 1996-2000: 21%; 2000-2005: 16%; p < 0.01). Increased age (odds ratio: 4.2, 95% confidence interval 3.6-4.9, p < 0.01) and obesity (2.1, 1.9-2.3, p < 0.01) were significantly associated with LNT across all time periods. Other significant factors included DCD and elevated ALT. For 2001-2005, population attributable risk indicate that age >40, abnormal ALT and obesity account for 32.6%, 25.3% and 9.2% of untransplanted livers, respectively. Use of expanded criteria livers has pushed LNT lower in spite of an aging and heavier donor population. Nevertheless, age and obesity still account for a significant portion of untransplanted livers.  相似文献   
997.
There is growing evidence that obesity in women lead to a more severe form of hyperandrogenism and other endocrine abnormalities which may have some health implications later in life. Obese females are at higher risk for metabolic syndrome due to severe hyperandrogenemia. Calculated values for free testosterone are equivalent to those obtained by equilibrium dialysis, which is one of the reference measurement procedures (RMP) for estimation of free testosterone and may be capable of replacing values estimated using RMP's. For adult women correlations of body mass index (BMI) with calculated free (cFT) and bioavailable testosterone (cBT) are still rare, while these data are reported for peripubertal and adolescent girls. In this study we aimed to investigate the association between BMI and different androgen parameters (including calculated free and bioavailable testosterone, free androgen index, and sex hormone-binding globulin [SHBG]) in adult women with Hirsutism and with PCOS. In hirsute women with BMI > or = 25 kg/m2 measured total testosterone (TT) was significantly higher, SHBG was significantly lower and the calculated androgen parameter (FAI, cFT and cBT) were significantly higher compared to women with BMI < 25 kg/m2. In PCOS women with BMI > or = 25 kg/m2 TT was significantly higher, SHBG was significantly lower and the calculated androgen parameter (FAI, cFT and cBT) were also significantly higher compared to women with BMI < 25 kg/m2. In both the Hirsutism and PCOS-group there was a positive correlation between BMI and TT, cFT, and cBT, while BMI was negatively correlated with SHBG. In summary, in adult women with Hirsutism and PCOS obesity is associated with increased levels of TT and decreased levels of SHBG resulting in significant elevated calculated free and bioavailable testosterone levels. Obesity might lead to a more severe form of hyperandrogenism with elevated calculated free and bioavailable testosterone in the study population.  相似文献   
998.
Degranulating mast cells are increased in the airway smooth muscle (ASM) of asthmatics, where they may influence ASM function. The aim of the present study was to determine whether histamine and tryptase modulate ASM cell granulocyte-macrophage colony-stimulating factor (GM-CSF) and RANTES (regulated on activation, normal T-cell expressed and secreted) release and also to examine which receptors are involved in this release. Confluent, quiescent ASM cells from asthmatic and nonasthmatic donors were treated with histamine (1 microM-100 microM) with and without histamine receptor antagonist pre-treatment, or the protease-activated receptor (PAR)-2 agonists tryptase (0.5-5 nM) and SLIGKV (100 and 400 microM). The cells were then stimulated with interleukin (IL)-1beta and/or tumour necrosis factor (TNF)-alpha (10 ng.mL(-1)) or left unstimulated for 24 h. Release of GM-CSF and RANTES was determined by ELISA and prostaglandin (PG)E(2) measured by enzyme immunoassay. Neither histamine nor tryptase induced ASM GM-CSF or RANTES secretion. However, histamine increased IL-1beta-induced GM-CSF release and markedly reduced TNF-alpha-induced RANTES release by both asthmatic and nonasthmatic cells to a similar extent, but did not modulate PGE(2) release. All changes involved activation of the histamine H1 receptor as they were partially or fully blocked by chlorpheniramine, but not ranitidine. Tryptase, via its proteolytic activity, also potentiated GM-CSF, but not RANTES, release from asthmatic and nonasthmatic ASM cells induced by both cytokines. PAR-2 involvement in the tryptase potentiation was unlikely because SLIGKV had no effect. In conclusion, mast cells, through histamine and tryptase, may locally modulate airway smooth muscle-induced inflammation in asthma.  相似文献   
999.
Objectives: Heavy smokers are a segment of the smoking population who are at increased risk of smoking-related morbidity and least likely to achieve cessation. This study identifies the impact of heavy smoking on quality of life by gender and describes the subpopulation for improved targeting.Methods: South Australian representative population data (n = 3010) was used to compare the health-related quality of life status of male and female heavy smokers as assessed by the SF-36.  相似文献   
1000.
In a prospective, randomized multicenter trial, 175 patients with abdominal aortic aneurysms were treated by conventional operation. Two types of polyester prostheses (Gelsoft Plus, Vascute Terumo Corp., Hamburg, Germany or Microvel, Boston Scientific, Ratingen, Germany) were selected randomly for implantation. Diameters ranged from 14 to 20 mm. The diameters of the grafts were measured by ultrasound postoperatively, as well as 6, 12, and 24 months after operation. Local and systemic complications were recorded. Dilation of the main body of the “Gelsoft plus” prosthesis was 19% within the first 12 months and 30% for the Microvel prosthesis. Extreme dilation was not observed. Thus, vascular prostheses must be chosen small enough and the dilation of 20–30% should be considered. The most frequent complication was incisional hernia (32%).  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