首页 | 官方网站   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   3513篇
  免费   194篇
  国内免费   48篇
医药卫生   3755篇
  2023年   22篇
  2021年   82篇
  2020年   42篇
  2019年   68篇
  2018年   78篇
  2017年   65篇
  2016年   71篇
  2015年   85篇
  2014年   101篇
  2013年   153篇
  2012年   261篇
  2011年   248篇
  2010年   137篇
  2009年   105篇
  2008年   150篇
  2007年   188篇
  2006年   169篇
  2005年   157篇
  2004年   155篇
  2003年   154篇
  2002年   125篇
  2001年   74篇
  2000年   87篇
  1999年   94篇
  1998年   40篇
  1997年   24篇
  1996年   21篇
  1995年   23篇
  1994年   16篇
  1993年   25篇
  1992年   70篇
  1991年   59篇
  1990年   59篇
  1989年   56篇
  1988年   29篇
  1987年   39篇
  1986年   36篇
  1985年   35篇
  1984年   32篇
  1983年   33篇
  1982年   15篇
  1981年   16篇
  1980年   21篇
  1979年   23篇
  1978年   19篇
  1974年   20篇
  1973年   34篇
  1972年   14篇
  1971年   16篇
  1970年   18篇
排序方式: 共有3755条查询结果,搜索用时 703 毫秒
81.
82.

Context:

This study was carried out as a part of an internal audit and is the largest series of patients having keratoglobus, published in the literature. Poor visual acuity of the patients indicates the blinding nature of the disease.

Aims:

We report our experience with patients having keratoglobus at a tertiary eye care center in India.

Settings and Design:

Retrospective study.

Materials and Methods:

We analyzed adults and pediatric patients (<16 years) with keratoglobus, seen during 2008–2012. The age, gender, consanguinity, presenting ocular signs, ocular and systemic associations, visual acuity, corneal topography, and surgeries were documented.

Results:

Forty-eight patients (mean age 22 ± 15 years, 31 males) having keratoglobus were analyzed. 21 patients (42 eyes) were <16 years. Twelve eyes (16 events) had positive history of trauma. The presenting clinical signs were corneal scars/scars of tear repair (15 eyes), hydrops, healed and acute (14 eyes) and corneal or globe rupture (9 eyes). Best-corrected visual acuity was >20/40 in 6/42 (14.3%) pediatric eyes and 15/53 (28.30%) adults. Visual acuity ranging from counting of fingers to no light perception was noted in 20/53 (37.74%) adults and 21/42 (50%) pediatric patients; 13/20 (65%) with blue sclera and 8/22 eyes (36.37%) without blue sclera. Vernal keratoconjunctivitis was present in one pediatric patient. Choroidal osteoma, retinitis pigmentosa, and retinal detachment were present in adults. Surgeries performed were corneal tear repair (5 eyes), tissue adhesive application (2 eyes), descematopexy (4 eyes) and penetrating keratoplasty (PK - 8 eyes: Three had post-PK glaucoma, graft failure-one eye, 4 patients wore scleral lens - prosthetic replacement of the ocular surface ecosystem).

Conclusions:

About 50% of pediatric eyes (65% having blue sclera) had no functional vision. Trivial trauma was responsible for corneal rupture indicating need for protective glasses. About 50% patients had post-PK glaucoma though grafts were clear.  相似文献   
83.

Purpose:

The purpose was to study choroidal thickness and its profile based on location in healthy Indian children using enhanced depth spectral-domain-optical coherence tomography (SD-OCT).

Methods:

In this cross-sectional observational study 255 eyes of 136 children with no retinal or choroidal disease were consecutively scanned using enhanced depth SD-OCT. Eyes with any ocular disease or axial length (AXL) >25 mm or < 20 mm were excluded. A single observer measured choroidal thickness from the posterior edge of the retinal pigment epithelium to the choroid/sclera junction at 500-microns intervals up to 2500 microns temporal and nasal to the fovea. Generalized estimating equations were used to evaluate the correlation between choroidal thickness at various locations and age, AXL, gender and spherical equivalent (SEq).

Results:

Mean age of the subjects was 11.9 ± 3.4 years (range: 5–18 years). There were 62 Females and 74 males. The mean AXL was 23.55 ± 0.74 mm. Mean subfoveal choroidal thickness was 312.1 ± 45.40 μm. Choroid was found to be thickest subfoveally, then temporally. Age, AXL and SEq showed a significant correlation with choroidal thickness, whereas gender did not affect choroidal thickness.

Conclusion:

Our study provides a valid normative database of choroidal thickness in healthy Indian children. This database could be useful for further studies evaluating choroidal changes in various chorioretinal disorders. Age and AXL are critical factors, which negatively correlated with choroidal thickness.  相似文献   
84.
The purpose of this study was to assess the effect of rabeprazole 20 mg once a day on patient-reported health-related quality of life in routine clinical practice. Patients with erosive gastroesophageal reflux disease participating in an open-label, 8-week study completed the SF-36 Health Survey before and after treatment with rabeprazole. For all SF-36 scales, there was a statistically significant (p 0.007) improvement in mean scores from baseline to week 8. Improvements in each of the subscales, except for physical functioning, general health, and mental health, were at least 5% in magnitude, a level considered clinically meaningful. Furthermore, while baseline scores were significantly poorer than general United States population scores, follow-up scores for four of the subscales (role limitations due to physical problems, social functioning, role limitations due to emotional problems, and mental health) were comparable to general population scores. In conclusion, rabeprazole significantly improved health-related quality of life in erosive gastroesophageal reflux disease patients and restored social functioning and emotional well-being to levels comparable to those observed in the United States general population.  相似文献   
85.
We report the crystal structure of Thermus aquaticus DNA polymerase I in complex with an inhibitory Fab, TP7, directed against the native enzyme. Some of the residues present in a helical conformation in the native enzyme have adopted a γ turn conformation in the complex. Taken together, structural information that describes alteration of helical structure and solution studies that demonstrate the ability of TP7 to inhibit 100% of the polymerase activity of the enzyme suggest that the change in conformation is probably caused by trapping of an intermediate in the helix-coil dynamics of this helix by the Fab. Antibodies directed against modified helices in proteins have long been anticipated. The present structure provides direct crystallographic evidence. The Fab binds within the DNA binding cleft of the polymerase domain, interacting with several residues that are used by the enzyme in binding the primer:template complex. This result unequivocally corroborates inferences drawn from binding experiments and modeling calculations that the inhibitory activity of this Fab is directly attributable to its interference with DNA binding by the polymerase domain of the enzyme. The combination of interactions made by the Fab residues in both the polymerase and the vestigial editing nuclease domain of the enzyme reveal the structural basis of its preference for binding to DNA polymerases of the Thermus species. The orientation of the structure-specific nuclease domain with respect to the polymerase domain is significantly different from that seen in other structures of this polymerase. This reorientation does not appear to be antibody-induced and implies remarkably high relative mobility between these two domains.  相似文献   
86.
87.
BACKGROUND: Spontaneous bacterial peritonitis (SBP) is a serious complication of cirrhosis with ascites, having high recurrence despite antibiotic prophylaxis. Small bowel dysmotility and bacterial overgrowth have been documented to be related to SBP. The purpose of the present paper was (i) to study whether addition of a prokinetic agent to norfloxacin ameliorates the development of SBP in high-risk patients; and (ii) to identify risk factors for SBP development. METHODS: A prospective, single blinded, randomized controlled trial was conducted in high-risk cirrhotic patients with ascites who had either recovered from an episode of SBP or who had low ascitic fluid protein. Norfloxacin 400 mg once daily (group I) or norfloxacin 400 mg once daily with cisapride 20 mg twice a day (group II) was given and occurrence of side-effects of therapy and mortality were recorded. RESULTS: Of the 94 patients, 48 (51%) were in group I, and 46 (49%) in group II. The actuarial probability of developing SBP at 12 month in group I was 56.8% and in group II, 21.7% (P = 0.026). Treatment failure was observed in five patients (10%) in group I and none in group II (P = 0.003). The actuarial probability of death at 18 months was 20.6% in group I and 6.2% in group II (P = 0.1). Low serum albumin, low ascitic fluid protein and alcoholic cirrhosis were related to development of SBP (P < 0.05). Additionally, low serum albumin (2.8 g/dL), gastrointestinal bleeding, alcoholic cirrhosis and low ascitic fluid protein were significantly associated with multiple occurrences of SBP. CONCLUSIONS: Prophylaxis with norfloxacin and cisapride significantly reduces the incidence of SBP in high-risk cirrhosis patients; low serum albumin, low ascitic fluid protein and alcoholic cirrhosis predispose to the development of SBP in high-risk cirrhosis patients; and low ascitic fluid protein should also be considered as a risk factor for the development of SBP requiring prophylaxis.  相似文献   
88.
89.
Oral feeding of sodium glycolate (50 mg/d/rat for ten days) caused a significant (P less than 0.001) increase in oxalate and taurine excretion and a decrease in liver protein content (P less than 0.05), glycolic acid oxidase levels (P less than 0.01), and glycolic acid dehydrogenase levels (P less than 0.01) as compared to normal untreated rats. Taurine (100 mg/d/rat), when administered along with glycolate, prevented these effects of glycolate as evident from normal urinary excretion of oxalate, liver protein content, glycolic acid oxidase, and glycolic acid dehydrogenase levels in glycolate- plus taurine-fed animals.  相似文献   
90.
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-23

京公网安备 11010802026262号