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   502篇
  免费   15篇
  国内免费   6篇
耳鼻咽喉   1篇
儿科学   40篇
妇产科学   31篇
基础医学   30篇
口腔科学   11篇
临床医学   50篇
内科学   84篇
皮肤病学   10篇
神经病学   6篇
特种医学   39篇
外科学   142篇
综合类   8篇
预防医学   10篇
眼科学   15篇
药学   18篇
肿瘤学   28篇
  2021年   5篇
  2018年   4篇
  2016年   6篇
  2015年   5篇
  2014年   9篇
  2013年   14篇
  2012年   10篇
  2011年   18篇
  2010年   15篇
  2009年   28篇
  2008年   14篇
  2007年   13篇
  2006年   13篇
  2005年   24篇
  2004年   18篇
  2003年   17篇
  2002年   17篇
  2001年   20篇
  2000年   12篇
  1999年   21篇
  1998年   20篇
  1997年   18篇
  1996年   13篇
  1995年   13篇
  1994年   13篇
  1993年   8篇
  1992年   10篇
  1991年   3篇
  1990年   9篇
  1989年   11篇
  1988年   12篇
  1987年   18篇
  1986年   9篇
  1985年   5篇
  1981年   6篇
  1980年   4篇
  1979年   5篇
  1978年   4篇
  1974年   4篇
  1972年   3篇
  1971年   8篇
  1970年   2篇
  1969年   5篇
  1968年   4篇
  1967年   2篇
  1966年   2篇
  1957年   2篇
  1955年   4篇
  1954年   3篇
  1937年   2篇
排序方式: 共有523条查询结果,搜索用时 156 毫秒
101.
102.
103.
Background Dermatitis artefacta (DA) is defined as all dermatological, self‐inflicted skin lesions, where the patient denies having produced the lesions. Objectives The purpose of this study is to make a single‐centre retrospective clinical review of patients diagnosed as DA of the breast. Materials and methods During a 30‐year period (1976–2006), patients diagnosed as DA of the breast, seen in the Department of Dermatology of the Virgen Macarena Hospital in Seville, were recorded. Clinical and epidemiological features are described. Results A total of 27 women with a mean age of 34.33 years were selected representing 13.43% of the total of DA patients recorded (n = 201) in this period. The most frequent clinical forms were: excoriations (nine patients, 33.33%) and ulcers (nine patients, 33.33%), followed by burns (six patients, 22.22%), blisters (one patient, 3.70%), contact dermatitis (one patient, 3.70%) and haematomas (one patient, 3.70%). Ten of the cases were located exclusively on the breasts, whereas 17 had also other locations such as face in seven cases, arms in five cases, abdomen in five cases and the entire body in two cases. Cutaneous lesions were treated with occlusive bandages using zinc paste or plaster splint when necessary. Conclusion To our knowledge, this is the major series of DA of the breast studied. This complicated psychodermatological condition requires a correct diagnosis, appropriate management and psychiatric assessment.  相似文献   
104.
Whereas the developed gut mucosal barrier prevents luminal bacteria from invading the host, bacterial translocation appears to be facilitated in the neonate. The aim of this study was to determine the extent to which bacteria spontaneously translocate from the gut to extraintestinal organs during the neonatal period and to relate translocation to the evolving intestinal flora in the rat. Newborn Sprague-Dawley rats suckled ad libitum and ate regular chow after weaning. A total of 167 rats were killed either immediately or at 1, 9, 14, 21, 26, or 42 days after delivery. Mesenteric lymph nodes (MLN), liver, heart blood, and the terminal ileal loop were harvested under sterile conditions and analyzed for aerobic and facultatively anaerobic bacteria by standard microbiologic procedures. Bacterial translocation to the MLN and liver began soon after birth and peaked during the second week. On day 14, translocation to any organ was present in 85% of rats. All cultures from the liver were sterile after day 26. By contrast, the fall in translocation to the MLN was incomplete, as 50% of pups still had positive MLN on day 42. Blood cultures were positive in three of the 167 rats. The intensity of translocation as determined by the number of organs infected significantly increased with the number of gram-negative enterics and gram-positive cocci in the gut and was negatively correlated with the percentage of lactobacilli from the total measured intestinal flora (P < 0.0001). In conclusion, bacterial translocation from the gut is a physiological and age-dependent phenomenon in the neonatal rat. Translocation appears to be facilitated when intestinal concentrations of gram-negative enterics and gram-positive cocci are high and when the concentration of lactobacilli is low.  相似文献   
105.
106.
Gastroesophageal reflux (GER) in infants becomes gastroesophageal reflux disease (GERD) through association with distinct clinical symptoms. Monitoring of pH is considered the standard diagnostic tool through which episodes of acidity can be detected. Apparently, however, the major amount of GER occurs in the physiologic esophageal pH range, which is concealed to pHmetry. Intraluminal impedance is a new method for pH-independent detection of esophageal bolus movement. Long-term measurements and combination with other diagnostic methods, eg, pHmetry or polygraphic recordings, are possible. Intraluminal impedance has proved especially useful in diagnosing GER and GERD in infants. It may develop into the ideal technique for this group of patients.  相似文献   
107.
AIM:To evaluate the efficacy and mechanism of action of NCB-02,a standardized Curcumin preparation,against 2,4-dinitrochlorobenzene(DNCB)-induced ulcerative colitis in rats.METHODS:Ulcerative colitis was induced in male rats by sensitizing with topical application of DNCB in acetone for 14 d and intra-colonol challenge with DNCB on day 15.A separate group of animals with vehicle treatment in similar fashion served as control group.Colitis rats were divided into different groups and treated with NCB-02 at doses of 25,50 and 100 mg/kg b.wt p.o.for 10 d.Sulfasalazine at a dose of 100 mg/kg b.wt for 10 d served as a reference group.On day 10 after respective assigned treatment,all the animals were euthanized and the length of the colon,weight of entire colon and distal 8 cm of the colon were recorded.The distal part of the colon was immediately observed under a stereomicroscope and the degree of damage was scored.Further distal 8 cm of the colon was subject to the determination of colonic myeloperoxidase(MPO),lipid peroxidation(LPO)and alkaline phosphatase (ALP)activities.A small piece of the sample from distal colon of each animal was fixed in 10% neutral buffered formalin and embedded in paraffin wax and sectioned for immunohistochemical examination of NFκ-B and iNOS expression.RESULTS:NCB-02 showed a dose dependent protection against DNCB-induced alteration in colon length and weight.NCB-02 treatment also showed a dose dependent protection against the elevated levels of MPO,LPO and ALP,induced by DNCB.NCB-02 demonstrated a significant effect at a dose of 100 mg/kg b.wt.,which was almost equipotent to 100 mg/kg b.wt.of sulfasalazine.Treatment with sulfasalazine and curcumin at a dose of 100 mg/kg b.wt.inhibited the DNCB-induced overexpression of NFκ-B and iNOS in the colon.CONCLUSION:Curcumin treatment ameliorates colonic damage in DNCB-induced colitic rats,an effect associated with an improvement in intestinal oxidative stress and downregulation of colonic NFκ-B and iNOS expression.  相似文献   
108.

Background

Hospitals have a critically important role in the management of mass causality incidents (MCI), yet there is little information to assist emergency planners. A significantly limiting factor of a hospital''s capability to treat those affected is its surgical capacity. We therefore intended to provide data about the duration and predictors of life saving operations.

Methods

The data of 20,815 predominantly blunt trauma patients recorded in the Trauma Registry of the German-Trauma-Society was retrospectively analyzed to calculate the duration of life-saving operations as well as their predictors. Inclusion criteria were an ISS ≥ 16 and the performance of relevant ICPM-coded procedures within 6 h of admission.

Results

From 1,228 patients fulfilling the inclusion criteria 1,793 operations could be identified as life-saving operations. Acute injuries to the abdomen accounted for 54.1% followed by head injuries (26.3%), pelvic injuries (11.5%), thoracic injuries (5.0%) and major amputations (3.1%). The mean cut to suture time was 130 min (IQR 65-165 min). Logistic regression revealed 8 variables associated with an emergency operation: AIS of abdomen ≥ 3 (OR 4,00), ISS ≥ 35 (OR 2,94), hemoglobin level ≤ 8 mg/dL (OR 1,40), pulse rate on hospital admission < 40 or > 120/min (OR 1,39), blood pressure on hospital admission < 90 mmHg (OR 1,35), prehospital infusion volume ≥ 2000 ml (OR 1,34), GCS ≤ 8 (OR 1,32) and anisocoria (OR 1,28) on-scene.

Conclusions

The mean operation time of 130 min calculated for emergency life-saving surgical operations provides a realistic guideline for the prospective treatment capacity which can be estimated and projected into an actual incident admission capacity. Knowledge of predictive factors for life-saving emergency operations helps to identify those patients that need most urgent operative treatment in case of blunt MCI.  相似文献   
109.

Background and purpose:

Vascular tolerance to nitroglycerin (GTN) may be caused by impaired GTN bioactivation due to inactivation of mitochondrial aldehyde dehydrogenase (ALDH2). As relaxation to GTN is reduced but still sensitive to ALDH2 inhibitors in ascorbate deficiency, we compared the contribution of ALDH2 inactivation to GTN hyposensitivity in ascorbate deficiency and classical in vivo nitrate tolerance.

Experimental approach:

Guinea pigs were fed standard or ascorbate-free diet for 2 weeks. Reversibility was tested by feeding ascorbate-deficient animals standard diet for 1 week. Nitrate tolerance was induced by subcutaneous injection of 50 mg·kg−1 GTN 4 times daily for 3 days. Ascorbate levels were determined in plasma, blood vessels, heart and liver. GTN-induced relaxation was measured as isometric tension of aortic rings; vascular GTN biotransformation was assayed as formation of 1,2-and 1,3-glyceryl dinitrate (GDN).

Key results:

Two weeks of ascorbate deprivation had no effect on relaxation to nitric oxide but reduced the potency of GTN ∼10-fold in a fully reversible manner. GTN-induced relaxation was similarly reduced in nitrate tolerance but not further attenuated by ALDH inhibitors. Nitrate tolerance reduced ascorbate plasma levels without affecting ascorbate in blood vessels, liver and heart. GTN denitration was significantly diminished in nitrate-tolerant and ascorbate-deficient rings. However, while the ∼10-fold preferential 1,2-GDN formation, indicative for active ALDH2, had been retained in ascorbate deficiency, selectivity was largely lost in nitrate tolerance.

Conclusions and implications:

These results indicate that nitrate tolerance is associated with ALDH2 inactivation, whereas ascorbate deficiency possibly results in down-regulation of ALDH2 expression.  相似文献   
110.
Almaguer‐Mederosa LE, Falcón NS, Almira YR, Zaldivar YG, Almarales DC, Góngora EM, Herrera MP, Batallán KE, Armiñán RR, Manresa MV, Cruz GS, Laffita‐Mesa J, Cyuz TM, Chang V, Auburger G, Gispert S, Pérez LV. Estimation of the age at onset in spinocerebellar ataxia type 2 Cuban patients by survival analysis. Previous studies have investigated the close association that exists between CAG repeat number and the age at onset in SCA2 = spinocerebellar ataxia type 2. These studies have focused on affected individuals. To further characterize this association and estimate the risk of a carrier developing SCA2 at a particular age as a function of a specific CAG repeat size, we have analyzed a large group of 924 individuals, including 394 presymptomatic and 530 affected individuals with a CAG repeat length of 32–79 units. Using a Kaplan–Meier survival analysis, we obtained cumulative probability curves for disease manifestation at a particular age for each CAG repeat length in the 34–45 range. These curves were significantly different (p < 0.001) and showed small overlap. All these information may be very valuable in predictive‐testing programs, in the planning of studies for the identification of other genetic and environmental factors as modifiers of age at onset, and in the design of clinical trials for people at enlarged risk for SCA2.  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