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   627篇
  免费   33篇
  国内免费   14篇
儿科学   21篇
妇产科学   4篇
基础医学   65篇
口腔科学   6篇
临床医学   74篇
内科学   103篇
皮肤病学   10篇
神经病学   22篇
特种医学   156篇
外科学   40篇
综合类   33篇
预防医学   24篇
眼科学   12篇
药学   28篇
中国医学   1篇
肿瘤学   75篇
  2022年   2篇
  2021年   4篇
  2020年   6篇
  2019年   7篇
  2018年   10篇
  2017年   8篇
  2016年   4篇
  2015年   6篇
  2014年   16篇
  2013年   22篇
  2012年   11篇
  2011年   12篇
  2010年   21篇
  2009年   29篇
  2008年   18篇
  2007年   17篇
  2006年   22篇
  2005年   18篇
  2004年   16篇
  2003年   16篇
  2002年   13篇
  2001年   22篇
  2000年   13篇
  1999年   18篇
  1998年   29篇
  1997年   41篇
  1996年   27篇
  1995年   25篇
  1994年   24篇
  1993年   19篇
  1992年   12篇
  1991年   13篇
  1990年   11篇
  1989年   24篇
  1988年   16篇
  1987年   17篇
  1986年   12篇
  1985年   13篇
  1984年   6篇
  1983年   11篇
  1982年   10篇
  1981年   11篇
  1980年   6篇
  1979年   4篇
  1978年   2篇
  1977年   3篇
  1976年   2篇
  1971年   1篇
  1967年   1篇
  1966年   1篇
排序方式: 共有674条查询结果,搜索用时 0 毫秒
1.
2.
Retrorenal colon: implications for percutaneous diskectomy   总被引:1,自引:0,他引:1  
Helms  CA; Munk  PL; Witt  WS; Davis  GW; Morris  J; Onik  G 《Radiology》1989,171(3):864-865
It has been recommended that computed tomography (CT) with the patient prone be performed in every patient undergoing percutaneous diskectomy; this would enable detection of a retrorenal location of the colon, which could interfere with the percutaneous procedure. In this evaluation of 346 prone CT studies, only one patient (0.29%) was found to have retrorenal or retropsoas bowel that would have been perforated at diskectomy. Because of this extremely low prevalence, the performance of prone CT in every patient undergoing percutaneous lumbar diskectomy is not believed to be necessary.  相似文献   
3.
Abdominal abnormalities in AIDS: detection at US in a large population   总被引:1,自引:0,他引:1  
  相似文献   
4.
Background: Spherophakia is an uncommon diagnosis. This is the first case report of spherophakia evaluated by ultrasound biomicroscopy.
Methods: Ultrasound biomicroscopy is a new diagnostic technique developed by one of the authors and provides images with microscopic resolution of the anterior segment. A patient with spherophakia was evaluated by ultrasound biomicroscopy (Zeiss-Humphrey, 50MHz) before and after YAG laser iridotomy.
Results: Ultrasound biomicroscopic assessment revealed a shallow anterior chamber, a very steep anterior lens curvature, iridolenticular contact, elongated zonules, and an increased distance between the lens equator and the ciliary processes. Angle closure glaucoma was due to a pupil block mechanism. The pupil block was relieved by YAG laser iridotomy.
Conclusions: Ultrasound biomicroscopy is a useful technique to confirm the diagnosis of spherophakia. The pupil block in spherophakia is relieved by YAG laser iridotomy.  相似文献   
5.
本文在胃癌行全胃或胃大部切除术引起的中等程度应激病人,随机分组对比观察了全肠外营养或TPN加用1,6-二磷酸果糖的效果。结果显示,与单纯TPN相比,TPN加用FDP后血清皮质醇和胰高血糖素等应激激素水平有所下降,尿中3-甲基组氨酸排出减少,累积氮平衡增加。  相似文献   
6.
H W Hsu  P Schwartzberg  S P Goff 《Virology》1985,142(1):211-214
A series of point mutations in the P30 domain of the Moloney murine leukemia virus gag gene was generated by bisulfite treatment of heteroduplex DNAs containing a single-stranded region in the gag gene. One virus bearing such a mutation exhibited a coordinate defect in gag and pol function, and was similar to previously described deletion mutants with alterations in this gene. One mutant virus displayed a different phenotype: it could assemble virion particles and provide pol function, but the particles were defective in the early stages of infection. The continued concordance of the mutants' failure or ability to both assemble virions and provide pol lends further support to the proposal that similar parts of the gag gene are required for these two processes.  相似文献   
7.
Dynamic CT features of hepatic abscesses   总被引:31,自引:0,他引:31  
Mathieu  D; Vasile  N; Fagniez  PL; Segui  S; Grably  D; Larde  D 《Radiology》1985,154(3):749-752
Forty hepatic abscesses were examined with dynamic computed tomography (CT). A "double target sign," consisting of a hypodense central area surrounded by first a hyperdense ring and then a hypodense zone, seems to be highly suggestive of abscess formation. In 12 cases, the hepatic parenchyma surrounding the lesion demonstrated transient hyperdensity after contrast injection, possibly due to localized hepatic venous obstruction secondary to acute hepatic inflammation. This is similar to the appearance of an arterioportal fistula.  相似文献   
8.
Summary The presence, chromatographic properties and localization of neuropeptide Y was demonstrated in postmortem human brain areas of neurologically and neuropsychiatrically normative controls using immunocytochemistry and high performance liquid chromatography combined with radioimmunoassay. NPY-immunoreactivity was found in many regions of the prosencephalon. Numerous perikarya and fibers were present in the neocortex, basal ganglia and limbic-hypothalamic areas. A moderate number of neurons and fibers was observed in the basal forebrain, including the septal complex. A comparative immunohistochemical investigation in perfusion-fixed brains of the old-world ape Saguinus oedipus revealed an almost identical distribution of NPY-immunoreactivity with only minor differences. Colocalization experiments on 1–2 m thin consecutive paraffin sections revealed a large number of NPY neurons throughout the human neostriatum and amygdaloid complex that were also positive for somatostatin. Our findings indicate that detection of neuropeptides in fresh or fixed post-mortem human tissue by different immunochemical methods may actually reflect the in vivo conditions. In addition, the wide distribution of NPY throughout the human brain and its colocalization with other neurotransmitters suggests a physiological role as neuroactive substance, i.e. neuromodulator in the primate central nervous system.  相似文献   
9.
OBJECTIVE: The ketogenic diet is a high-fat, low-protein, low-carbohydrate diet developed in the 1920s for the treatment of children with difficult to control seizures. Despite advances in both the pharmacotherapy and the surgery of epilepsy, many children continue to have difficult-to-control seizures. This prospective study sought to determine the ketogenic diet's effectiveness and tolerability in children refractory to today's medications. METHODS: One hundred fifty consecutive children, ages 1 to 16 years, virtually all of whom continued to have more than two seizures per week despite adequate therapy with at least two anticonvulsant medications, were prospectively enrolled in this study, treated with the ketogenic diet, and followed for a minimum of 1 year. Seizure frequency was tabulated from patients' daily seizure calendars and seizure reduction calculated as percentage of baseline frequency. Adverse events and reasons for diet discontinuation were recorded. RESULTS: The children (mean age, 5.3 years), averaged 410 seizures per month before the diet, despite an exposure to a mean of 6.2 antiepileptic medications. Three months after diet initiation, 83% of those starting remained on the diet and 34% had >90% decrease in seizures. At 6 months, 71% still remained on the diet and 32% had a >90% decrease in seizures. At 1 year, 55% remained on the diet and 27% had a >90% decrease in seizure frequency. Most of those discontinuing the diet did so because it was either insufficiently effective or too restrictive. Seven percent stopped because of intercurrent illness. CONCLUSIONS: The ketogenic diet should be considered as alternative therapy for children with difficult-to-control seizures. It is more effective than many of the new anticonvulsant medications and is well tolerated by children and families when it is effective.  相似文献   
10.
We report a case of an assisted pregnancy in an asymptomatic woman who was found to have an extrauterine mass on ultrasound and MRI. This complex mass had equivocal imaging features and was found to be a ruptured ovarian ectopic pregnancy at surgery. This case illustrates that vigilance is required regarding the possibility of coexisting ectopic and intrauterine pregnancy following assisted conception, even in entirely asymptomatic cases.  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