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   382篇
  免费   11篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   56篇
妇产科学   27篇
基础医学   39篇
口腔科学   2篇
临床医学   11篇
内科学   47篇
皮肤病学   5篇
神经病学   2篇
特种医学   2篇
外科学   37篇
综合类   7篇
预防医学   20篇
眼科学   80篇
药学   16篇
中国医学   1篇
肿瘤学   40篇
  2023年   2篇
  2021年   6篇
  2020年   4篇
  2019年   4篇
  2018年   5篇
  2017年   4篇
  2015年   3篇
  2014年   10篇
  2013年   14篇
  2012年   26篇
  2011年   26篇
  2010年   23篇
  2009年   12篇
  2008年   23篇
  2007年   23篇
  2006年   12篇
  2005年   26篇
  2004年   31篇
  2003年   26篇
  2002年   22篇
  2001年   2篇
  1999年   4篇
  1998年   4篇
  1997年   3篇
  1996年   6篇
  1995年   4篇
  1994年   3篇
  1993年   4篇
  1992年   2篇
  1991年   4篇
  1989年   3篇
  1988年   1篇
  1987年   2篇
  1986年   5篇
  1985年   4篇
  1984年   2篇
  1983年   4篇
  1982年   1篇
  1981年   5篇
  1980年   7篇
  1979年   6篇
  1976年   1篇
  1973年   1篇
  1972年   3篇
  1970年   1篇
  1962年   1篇
  1961年   2篇
  1960年   2篇
  1959年   1篇
  1958年   1篇
排序方式: 共有394条查询结果,搜索用时 15 毫秒
121.
During the last three years, there had been several publications from USA and Africa, highlighting maternal and child health problems in HIV infection. Available data suggest that pregnancy might accelerate progression of HIV infection in the mother. About 50% of infants born to HIV infected mothers are likely to be infected at birth or in the neonatal period. Nearly half of the infected infants die before two years of age. HIV infection in childhood following transfusion of blood from HIV infected donor has been reported. There had been speculations on the possible role of improperly sterilised syringes and needles in transmission of HIV infection in Africa. The available guideline drawn by national (Centre for Disease Control, Atlanta,USA) and international (WHO) agencies regarding provision of MCH care to HIV infected individuals and in situations where information on HIV infection status of the person is not known are reviewed, with special reference to the situation in developing countries like India.  相似文献   
122.
Purpose:To evaluate ocular tolerance of methylated collagen gel injected intravitreally and into the anterior chamber. Methods: Methylated collagen (type I/III) was tested in New Zealand white rabbits. Vitreous cavity: After pars plana vitrectomy, methylated collagen gel was injected intravitreally. The eyes were examined clinically; electroretinogram recordings were made before and after surgery. Vitreous samples were taken for immunological analysis for the presence of the injected collagen. The rabbits were sacrificed 6 months after surgery; the retina was evaluated by light microscopy. Anterior chamber: In another group of rabbits, methylated collagen gel (0.2 ml, 0.1 ml, or 0.05 ml) was injected into the anterior chamber after paracentesis. The eyes were examined with a slit lamp; intraocular pressure was measured postinjection. The rabbits were sacrificed after 4 months; the corneas were evaluated histologically. Results: Vitreous cavity: The fundus view was clear for 6 months after intravitreal injection. Scotopic and photopic electroretinograms were normal in 6/7 eyes; one eye experienced a mild decrease one month postoperatively. No abnormal changes were found in the retinal histology. Anterior chamber: Some corneas were hazy and edematous around the injection site for one week. The injected collagen appeared in bundles, patches, and little pieces in the anterior chamber with precipitates on the corneal endothelium, pupillary margin, and the anterior capsule of the lens. The collagen diminished gradually, without causing permanent opacity. Histologically, the corneal endothelium in the eye which received 0.2 ml collagen showed a mild distention of the mitochondriae and vesicle formation between endothelial cells under transmission electron microscope. Conclusion: Methylated collagen gel was tolerated by the eye after intravitreal injection. Localized temporary clinical and mild ultrastructural corneal changes were observed after anterior chamber injection.  相似文献   
123.
During the last decade there have been many reports indicating a decline in breast feeding practices in the urban areas of developing countries. This decline might have adverse effects on maternal and child health. A study of 1079 urban hospital attending women was undertaken to evaluate their breast feeding practices. Prolonged (mean duration of lactation 19.8 months) and successful lactation (failure of lactation occurred in only 3.5%) was common among this group. But a trend toward shorter duration of breast feeding was found among educationally and economically better off segment. There was very good correlation between mean duration of lactation, lactational amenorrhea, and interpregnancy interval. Therefore, it is possible that decrease in duration of lactation might result in shorter interpregnancy interval. The duration of lactation appeared to be "fixed" for each individual irrespective of age and parity. This in turn resulted in "fixed" duration of lactational amenorrhea and interpregnancy interval under conditions of unhindered lactation and uncontrolled fertility. Conception during lactational amenorrhea was low (7.7%) but once periods were reestablished lactation offered very little protection against conception.  相似文献   
124.
Graves' disease (GD) is an autoimmune disorder of the thyroid gland and both environmental and genetic factors contribute to disease aetiology. Cytokines, such as interleukin 4 (IL-4) and interleukin 10 (IL-10), are involved in the immune response and may be implicated in the autoimmune disease process. Associations have been reported between single nucleotide polymorphisms (SNPs) of IL-10 and the Ile50Val polymorphism of the IL-4 receptor gene (IL-4R) gene and atopy and autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. The autoimmune diseases cluster within families and susceptibility genes may overlap between the different disorders. Therefore, we investigated 5 SNPs (-592C/A, -657G/A, - 819C/T, -1349A/G, and -2013G/A) in the promoter region of the IL-10 and the Ile50Val polymorphism (A/G) in the IL-4R in a large UK population based case-control dataset with GD. No association was found between the polymorphisms studied and GD and no significant differences were found in genotype or allele frequencies between the patients and control subjects. We conclude these polymorphisms of IL-10 and IL-4R previously associated with other immune mediated diseases, do not confer susceptibility to GD in white Caucasians in the United Kingdom.  相似文献   
125.
A 10 year study of malaria during 1989-98 recorded an increase in the incidence of malaria from 0.22 in 1989 to 1.3 in 1996 following which it has reached a plateau. The cases were chiefly from Karnataka, Andhra Pradesh and Tamil nadu. The P. falciparum infection and mixed infections (P. falciparum and vivax) were found to be on the rise. Peak of malaria cases were recorded in the months of June-July and in Oct-Nov coinciding with the rains showing a seasonal pattern. The common haematological findings were anemia, thrombocytopenia, pancytopenia and leucopenia. Complications noted in our study were haemolysis, renal failure, hepatopathy and cerebral malaria. The unusual cases were congenital malaria, malaria with sickle cell anemia, AIHA and G-6PD deficiency. Mortality due to cerebral malaria was found to be 13.5%.  相似文献   
126.
This study examined the influence of activated support schemas on cardiovascular reactivity (CVR) during an anger-recall interview. Eighty Chinese female undergraduates wrote about a supportive tie or a casual acquaintance and subsequently disclosed an anger-provoking event while their heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured. Compared to participants in the 'acquaintance' condition, those in the 'support' condition showed lower HR, SBP and DBP reactivity, as well as smaller state anger increases and less negative appraisals of the recalled anger event. Reactivity increased as a function of trait anger. High trait anger individuals also had greater increases in state anger and more negative appraisals of the recalled event compared to their low trait anger counterparts. Support schema activation reduced the effects of trait anger on CVR such that high trait anger individuals in the 'support' condition had significantly lower CVR compared to high trait anger individuals in the 'acquaintance' condition. These findings suggest that social support schemas may have beneficial effects even in the absence of actual, enacted support.  相似文献   
127.
Trichinella spiralis first-stage larvae infect susceptible hosts by invading epithelial cells that line the small intestine. During this process the larva disgorges several glycoproteins that bear an unusual, highly antigenic sugar moiety, tyvelose (3,6-dideoxy arabinohexose). Monoclonal antibodies specific for tyvelose protect the intestine against infection, implicating tyvelose-bearing glycoproteins as mediators of invasion and niche establishment in the intestinal epithelium. In order to investigate these glycoproteins at the molecular level, we first prepared monoclonal anti-peptide antibodies. The antibodies bind a family of glycoproteins that are present in excretory-secretory products of first-stage larvae and are delivered to epithelial cells during invasion by T. spiralis. The major species present in an affinity purified fraction of crude T. spiralis antigens were subjected to tryptic peptide digestion. De novo amino acid sequencing of the peptides using Q-TOF tandem mass spectrometry, in combination with database searches and antibody screening of an L1 cDNA library, showed that the glycoproteins are variably glycosylated homologues of the serine protease family.  相似文献   
128.
Hepatic artery (HA) complications after liver transplant (LT) can lead to biliary complications, graft failure, and mortality. Although microsurgery has been established to improve anastomotic outcomes, it prolongs surgical time and has not reached widespread adoption at all transplant centers. We investigated the incidences of arterial, biliary complications and outcomes after using microsurgery to anastomose HA during LT. Retrospective cohort of consecutive LT performed from 2006 to 2018 was reviewed for operative details and postoperative outcomes. Cox-regression models were used to investigate the relationship between variables and outcomes. Eighty (62.5%) LTs (Group 1) were performed without and compared with 48 (Group 2) with microsurgical anastomosis of HA. Both groups were comparable in terms of arterial and biliary anastomoses performed. Incidence of early HA thrombosis was similar (6.2% vs 2.1%, P = .28). Group 2 had lower incidence of short- and long-term arterial complications, especially amongst living donor liver transplantations (LDLT) (5.3% vs 35.0%, P = .022). On multivariate analysis, microsurgery was associated with lower risk (hazard ratio [HR] 0.09, 95% confidence interval [CI] 0.01-0.71) of, and LDLT had higher risk (HR 4.23, 95% CI 1.46-12.27) of arterial complications. Biliary complications were associated with LDLT (HR 3.91, 95% CI 1.30-11.71) and dual biliary anastomoses (HR 5.26, 95% CI 1.15-24.08) but not with occurrence of HA complications. Worse patient survival was associated with the occurrence of any HA complication (HR 4.11, 95% CI 1.78-9.48). Hepatic arterial complications can be reduced using microsurgical techniques for the anastomosis, resulting in improved patient survival outcomes after liver transplantation.  相似文献   
129.
IntroductionReconstitution of hepatic artery inflow is essential for a successful liver transplantation. Living donor transplantation presents additional challenges in the form of a short and small donor vessel stump, exacerbating the poor surgical access for microsurgery. Few reports have described the use of the radial artery as an interposition graft in liver transplantation; we present a series of 6 cases and discuss the technical merits of this procedure.MethodsRetrospective review of consecutive patients undergoing living donor liver transplantation from December 2015 to December 2019 was performed. Demographics, operative details, and postoperative outcomes were reviewed.ResultsTwenty-two patients underwent living donor liver transplantation. Radial artery interposition grafting was used in 6 cases, including 1 salvage case for hepatic artery thrombosis. One patient developed hepatic artery stenosis (2 weeks postoperatively) that was conservatively managed. After radial artery grafting, all patients had normal resistive indices on duplex ultrasonography at up to 20 months postoperatively. The mean follow-up was 15.2 months.ConclusionWhen faced with a significantly short vessel stump or caliber mismatch, radial artery interpositional grafting is a safe and useful technique for reducing tension and overcoming vessel size mismatch in hepatic artery reconstruction.  相似文献   
130.
Purpose: To compare reading performance as mediated by the healthy eye and the affected eye of individuals with recent onset, unilateral, exudative age-related macular degeneration.
Methods: The reading performance of eight subjects (76.3 ± 5.3 years) was assessed under monocular viewing conditions with the affected and the healthy eye. Eye movements were recorded using a spectacle-mounted, infrared limbal reflection system whilst the subjects read short stories (65 words) printed in 16 point Times Roman font at a working distance of 25 cm. Comprehension was assessed by 'free' recall at the end of each story.
Results: Acuity in the affected eyes ranged from 0.40 to 0.80 (log MAR) and in the healthy eyes from 0.00 to 0.20. When using the affected eye, reading speed was reduced by 50%, compared to reading with the healthy eye, though comprehension scores were similar. There was also a significant increase ( P < 0.01) in the durations of fixation pauses, the time between the initiation of the return sweep and the first forward saccade on the subsequent line and the numbers of regressive saccades, with each forward saccade covering fewer letters. Fixation durations were positively correlated with the mean depth of the field defect.
Conclusions: The results seem to indicate that although the motor aspects of reading are affected in the initial stages of the visual loss, comprehension is relatively unaffected for short, simple passages of text.  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