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   12018篇
  免费   720篇
  国内免费   70篇
耳鼻咽喉   66篇
儿科学   361篇
妇产科学   251篇
基础医学   2038篇
口腔科学   113篇
临床医学   1150篇
内科学   3018篇
皮肤病学   193篇
神经病学   1051篇
特种医学   295篇
外科学   1631篇
综合类   41篇
现状与发展   1篇
一般理论   9篇
预防医学   744篇
眼科学   78篇
药学   755篇
中国医学   21篇
肿瘤学   992篇
  2023年   47篇
  2022年   105篇
  2021年   247篇
  2020年   151篇
  2019年   241篇
  2018年   285篇
  2017年   184篇
  2016年   220篇
  2015年   243篇
  2014年   385篇
  2013年   530篇
  2012年   867篇
  2011年   906篇
  2010年   498篇
  2009年   504篇
  2008年   815篇
  2007年   880篇
  2006年   863篇
  2005年   929篇
  2004年   880篇
  2003年   829篇
  2002年   790篇
  2001年   102篇
  2000年   59篇
  1999年   131篇
  1998年   173篇
  1997年   129篇
  1996年   94篇
  1995年   98篇
  1994年   75篇
  1993年   78篇
  1992年   49篇
  1991年   50篇
  1990年   46篇
  1989年   33篇
  1988年   33篇
  1987年   41篇
  1986年   30篇
  1985年   11篇
  1984年   19篇
  1983年   24篇
  1982年   17篇
  1981年   26篇
  1980年   30篇
  1979年   14篇
  1978年   9篇
  1977年   8篇
  1976年   5篇
  1974年   4篇
  1968年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
The perception of the pain, and the “work of pain” which ensues from it, bound to the notion of trauma-hurt to subjects presenting a thought operating and a depression main part, sign a physical fixation for an object psychically not representable. These subjects have a real incapacity to perceive and symbolize the affect of psychic suffering as well borderline teenagers (self-harm). Having reminded the Freudian and psychoanalytical conceptions on the pain, the operating functioning and the self-harm behaviour, the authors will refer to certain sociological works describing certain characteristics of our post-modern social, cultural and linguistic organization to underline the impact of these in the increase of the behaviour of search for the pain to borderline patients or with the perception of the pain as only sign of a mental suffering impossible to symbolize. So, we notice that the loss of symbolic structuring of our post-modern civilization, the ascent in power of the thought operating, the social and domestic disorganizations, have a real cost on our contemporaries psychic and somatic health, particularly on the most numerous among them as teenagers.  相似文献   
22.
The generation of a novel transgenic mouse model of polycystic kidney disease with a construct (SBM) that links the coding region of the c-myc proto-oncogene to the simian virus 40 enhancer and beta-globin promoter was previously reported (see reference 1). In order to determine the site of origin and histogenesis of renal cysts in this model, lectin/immunohistochemical and electron microscopic studies on mice of varying ages (from birth to adulthood) are described here. Cysts are detectable at birth and increase in number and diameter with age. Cysts predominantly involve the collecting tubules of young transgenic mice but progressively affect the proximal tubules with advancing age. A minority of cysts are of distal tubular origin in all age groups studied. Tubular hyperplasias are primarily reactive with proximal tubular markers and appear to precede the development of proximal tubular cysts in adult mice. This particular phenotypic evolution of polycystic kidney disease with advancing age suggests that the cystogenic potential of the transgene is modulated by yet unidentified tubular segment-specific responses.  相似文献   
23.
A case of postnephrectomy arteriovenous fistula of the right renal pedicle is reported here. The diagnosis was confirmed by angiography, and successful treatment was achieved using detachable balloon.  相似文献   
24.
Objective: To identify factors that affect operative mortality and morbidity and long-term survival after completion pneumonectomy. Methods: We retrospectively reviewed the charts of consecutive patients who underwent completion pneumonectomy at our cardiothoracic surgery department from January 1996 to December 2005. Results: We identified 69 patients, who accounted for 17.8% of all pneumonectomies during the study period; 22 had benign disease and 47 malignant disease (second primary lung cancer, n = 19; local recurrence, n = 17; or metastasis, n = 11). There were 50 males and 19 females with a mean age of 60 years (range, 29–80 years). Postoperative mortality was 12% and postoperative morbidity 41%. Factors associated with postoperative mortality included obesity (p = 0.005), coronary artery disease (p = 0.03), removal of the right lung (p = 0.02), advanced age (p = 0.02), and renal failure (p < 0.0001). Preoperative renal failure was the only significant risk factor for mortality by multivariate analysis (p = 0.036). Bronchopleural fistula developed in seven patients (10%), with risk factors being removal of the right lung (p = 0.04) and mechanical stump closure (p = 0.03). Overall survival was 65% after 3 years and 46% after 5 years. Long-term survival was not affected by the reason for completion pneumonectomy. Conclusion: Although long-term survival was acceptable, postoperative mortality and morbidity rates remained high, confirming the reputation of completion pneumonectomy as a challenging procedure. Significant comorbidities and removal of the right lung were the main risk factors for postoperative mortality. Improved patient selection and better management of preoperative renal failure may improve the postoperative outcomes of this procedure, which offers a chance for prolonged survival.  相似文献   
25.
We performed a prospective study to analyze the functional results following elective laparoscopic sigmoidectomy for computed tomography (CT)-proven diagnosis of acute diverticulitis and review the literature. Forty-three of 45 available patients (96%) who had laparoscopic sigmoidectomy for CT-proven acute diverticulitis answered, after a mean time of 40 months, a questionnaire exploring new abdominal symptoms, bowel function, and the patient’s own judgement of the surgical outcome. Surgical technique aimed at removing all the sigmoid by taking down the splenic flexure and do a colorectal anastomosis. Four patients (9%) complained of new abdominal pain. Bowel function was reported as better for 24 patients (56%), unchanged for 16 patients (37%), and worse for 3 (7%). Twenty patients (47%) considered their final result as excellent to good, 17 patients (40%) as satisfying, and 6 patients (13%) as mediocre. Male gender, absence of preoperative history compatible with an irritable bowel syndrome, length of resected sigmoid and residual acute inflammation on histology are statistically predictive of a better postoperative degree of satisfaction. After elective laparoscopic sigmoidectomy for CT-proven diverticulitis, a great majority of patients are very satisfied with their postoperative general comfort.  相似文献   
26.
27.
Background: Remifentanil-induced secondary hyperalgesia has been documented experimentally in both animals and healthy human volunteers, but never clinically. This study tested the hypotheses that increased pain sensitivity assessed by periincisional allodynia and hyperalgesia can occur after relatively large-dose intraoperative remifentanil and that small-dose ketamine prevents this hyperalgesia.

Methods: Seventy-five patients undergoing major abdominal surgery were randomly assigned to receive (1) intraoperative remifentanil at 0.05 [mu]g [middle dot]kg-1 [middle dot]min-1 (small-dose remifentanil); (2) intraoperative remifentanil at 0.40 [mu]g [middle dot]kg-1 [middle dot]min-1 (large-dose remifentanil); or (3) intraoperative remifentanil at 0.40 [mu]g [middle dot]kg-1 [middle dot]min-1 and 0.5 mg/kg ketamine just after the induction, followed by an intraoperative infusion of 5 [mu]g [middle dot] kg-1 [middle dot] min-1 until skin closure and then 2 [mu]g [middle dot]kg-1 [middle dot]min-1 for 48 h (large-dose remifentanil-ketamine). Pain scores and morphine consumption were recorded for 48 postoperative hours. Quantitative sensory tests, peak expiratory flow measures, and cognitive tests were performed at 24 and 48 h.

Results: Hyperalgesia to von Frey hair stimulation adjacent to the surgical wound and morphine requirements were larger (P < 0.05) and allodynia to von Frey hair stimulation was greater (P < 0.01) in the large-dose remifentanil group compared with the other two groups, which were comparable. There were no significant differences in pain, pressure pain detection threshold with an algometer, peak flow, cognitive tests, or side effects.  相似文献   

28.
The diversity of the B cell repertoire of Cx knockout mice is limited by the expression of four λ light chain types. Among the spleen B cells, λ1 is expressed by the majority (58%) of cells, and λ3 by the minority (8%), while λ2(V2) and λ2(Vx) are expressed in intermediate quantities (18% and 16%, respectively). To assess the influence of mechanistic pressures on the λ subtype distribution, the proportions of the different λ rearrangements were determined in various B cell subpopulations divided on the basis of the λ subtype expressed, and the VλJλ junction sequences were studied at different steps of B cell differentiation (pre-B, immature and mature B cells). The data show that (1) the ratio of productive/non-productive VJ junctions is determined by the nature of the λ segments that are rearranged as can be observed in the pre-B cells, (2) V1-J1 non-productive rearrangements are often found in the λ1-negative B cells in the periphery, and (3) V1J3 junctions are often non-productive regardless of the nature of the cells analyzed. Our results, therefore, suggest that a strong probability of initiating a V1-J1 rearrangement and a weak probability of giving a productive V1J3 junction are responsible for the λ1 dominance and the λ3 under-expression, respectively. The intermediate proportion of λ2(V2) subtype is most likely due to a probability of obtaining a productive joint that is better than that for V1J3 and a probability of initiating a rearrangement that is lower than that for V1J1. However, the λ2(Vx) cell proportion cannot be determined only by these parameters.  相似文献   
29.
Transmetallation between commercially available solutions of gadolinium (Gd) chelates and the zinc (Zn)-dependent angiotensin-converting enzyme (ACE) was investigated. In vitro, the strongest inhibitions were observed for the linear Gd complexes, Gd diethylene-triamine pentaacetic acid (DTPA) bis-methylamide (BMA) (IC50 = .016 ± .006 mmol/1) and Gd-DTPA (IC50 = .350 ± .034 mmol/1). The two macrocycles Gd tetraazacyclododecane tetraacetic acid (DOTA) and Gd-HP-DO3A were similar and 400 times less active than Gd-DTPA-BMA. These effects were mainly due to the presence of free ligand for DTPA and calcium (Ca) chelate in the case of DTPA-BMA because the addition of Zn2+ in the same quantities suppresses their inhibitory effects. In vivo, these two solutions of linear Gd chelates significantly inhibited ACE activity (Gd-DTPA: 67 ± 9% versus baseline; and Gd-DTPA-BMA: 73 ± 2% versus baseline at the clinical dose of .1 mmol/kg), whereas no significant effect was observed for the two macrocyclic chelates Gd-DOTA and Gd-HP-DO3A. Formulating the Gd chelate solution with either an excess of free ligand or Ca chelate (to decrease Gd3+ release) in the case of linear Gd chelate may have deleterious biologic consequences.  相似文献   
30.
A case of hyperreactio luteinalis in an otherwise normal pregnancy is reported. Ascites was present, but no peritoneal implants or adenopathy were seen. Findings that would have suggested the correct diagnosis are the symmetrical and bilateral pattern of the mass, as well as the rather uniform size of the loculi, which were 1 to 3 cm in diameter.  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