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   13764篇
  免费   1102篇
  国内免费   112篇
耳鼻咽喉   144篇
儿科学   313篇
妇产科学   479篇
基础医学   1851篇
口腔科学   256篇
临床医学   1775篇
内科学   2611篇
皮肤病学   163篇
神经病学   1141篇
特种医学   355篇
外科学   1746篇
综合类   382篇
现状与发展   1篇
一般理论   3篇
预防医学   1044篇
眼科学   244篇
药学   1169篇
  4篇
中国医学   209篇
肿瘤学   1088篇
  2023年   118篇
  2022年   208篇
  2021年   356篇
  2020年   251篇
  2019年   360篇
  2018年   421篇
  2017年   290篇
  2016年   277篇
  2015年   388篇
  2014年   492篇
  2013年   714篇
  2012年   931篇
  2011年   1072篇
  2010年   634篇
  2009年   500篇
  2008年   799篇
  2007年   802篇
  2006年   776篇
  2005年   765篇
  2004年   676篇
  2003年   612篇
  2002年   562篇
  2001年   293篇
  2000年   250篇
  1999年   222篇
  1998年   119篇
  1997年   110篇
  1996年   68篇
  1995年   102篇
  1994年   94篇
  1993年   79篇
  1992年   150篇
  1991年   121篇
  1990年   116篇
  1989年   80篇
  1988年   74篇
  1987年   85篇
  1986年   57篇
  1985年   71篇
  1984年   82篇
  1983年   54篇
  1982年   75篇
  1981年   61篇
  1980年   63篇
  1979年   48篇
  1978年   42篇
  1976年   53篇
  1975年   49篇
  1974年   41篇
  1973年   40篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
11.
12.
The relationship of perceived control over daily uplifts and hassles to depression and restraint was examined in a sample of 140 middle-class sixth graders. Results indicated that greater control over uplifts was associated with better functioning and lower control over hassles with poorer functioning, even after partialing out the respective number of uplifts and hassles reported. Moreover, when directly compared, control over uplifts showed more powerful associations with adaptational outcomes than did control over hassles. In a separate analysis, the number of uplifts over which children reported high control showed opposite relationships to adaptational outcomes than did the number of uplifts over which children reported low control. A different pattern appeared for hassles. Although the number of hassles with low control was associated with poorer functioning, the number of hassles over which children had high control was unrelated to adaptational outcomes. The possibility that control operates somewhat differently for positive and negative events is discussed.This research was supported by a grant to the second author from the Stanford Center for the Study of Families, Children and Youth. The authors are grateful to Rachelle Hacket for data analysis, Tom Gehring for data collection, and Susan Nolen-Hoeksema for critical comments.  相似文献   
13.
BACKGROUND: A venous lake is a venous ectasia that appears mostly on the lower lip and other sun-exposed areas of an older person. Treatment of lip venous lake includes surgical excision, laser therapy, infrared coagulation, and cryotherapy. Although the use of sclerotherapy on varicose veins, leg telangiectasia, hemorrhoids, and hemangiomas is well established, the use of sclerotherapy for lip venous lake has not been reported. OBJECTIVE: We present two cases of lip venous lake treated with intralesional injection of 1% polidocanol. METHOD: Two cases are reported, and literature is reviewed. RESULT: The lesions virtually disappeared, leaving an inconspicuous scar, with two sessions of sclerotherapy. Side effects were not observed. CONCLUSION: Sclerotherapy with polidocanol is effective in the treatment of lip venous lake and offers an alternative to conventional methods.  相似文献   
14.
Effects of stimulation of brainstem sites on hemodynamics and plasma catecholamine levels were assessed in cats under chloralose-urethane anesthesia. Pressor areas of the dorsal medulla (DM) and ventrolateral medulla (VLM) and the depressor area of the paramedian reticular nucleus (PRN) were stimulated electrically using a monopolar electrode, or chemically using sodium glutamate microinjection. Plasma levels of norepinephrine (NE) and epinephrine (EPI) were measured in caval blood above the adrenal veins. Electrical stimulation of the DM and VLM produced increases in blood pressure and in plasma NE and EPI levels that were enhanced after acute vagotomies. The NE and EPI responses were attenuated after acute, bilateral adrenalectomies, confirming augmented adrenomedullary secretion, whereas the pressor responses were intact. Injection of sodium glutamate into the same pressor regions of the DM or VLM also produced pressor responses and elevated plasma catecholamine levels, indicating that the responses resulted from activation of neuronal perikarya. Stimulation of the PRN attenuated pressor and catecholamine responses during stimulation of the DM and VLM. The results indicate that pressor responses during stimulation of the DM and VLM are due at least partly to activation of perikarya in these regions, are associated with but not dependent on adrenomedullary activation, and are enhanced after vagotomy; and that neurons of the PRN exert inhibitory modulation of the pressor and adrenomedullary responses during stimulation of VLM and DM.  相似文献   
15.
Pelvic ultrasound is a widely used diagnostic tool and accessto this investigation is not universally available to all generalpractitioners (GPs). The aim of this study was to assess ifGPs working in the United Arab Emirates (UAE) were using pelvicultrasound appropriately by determining the rates of diagnosticyield and referral after the investigation. It was then ascertainedif these results were affected by the post-graduate trainingor gender of the doctor. The subjects were adult females whohad had a pelvic ultrasound ordered by a GP over a 2-month period.A chart review determined the presenting complaint, the completenessof the request form, the result of the ultrasound and subsequentmanagement of the patient. Diagnostic yields and referral rateswere similar to those found in other studies and were unaffectedby the post graduate training or gender of the doctor or theamount of information contained in the request form. This studysupports the premise that GPs can use pelvic ultrasound appropriatelyand should be allowed free access to this investigation.  相似文献   
16.
17.
The random amplification of polymorphic DNA (RAPD method), was used to derive fragments of DNA of the coccidial parasiteEimeria tenella for use both as genetic markers and as an aid for the discrimination of different wild-type and attenuated populations. Of 41 arbitrarily chosen 9-to 27-mer primers, 24 yielded useful arrays of fragments following low-stringency annealing conditions and the resultant profiles were generally very reproducible. One non-variant fragment of 2 kb hybridised to a single chromosome (number 12) and four variant fragments were identified. These results strongly suggest that the RAPD method may be an extremely useful tool for studies on various aspects of the genetic organisation of coccidial parasites.  相似文献   
18.
19.
Spontaneous intracranial hypotension (SIH) is characterized by orthostatic headache and the cause is usually cerebrospinal fluid leaks in spine level. Most patients with SIH have a benign course. Epidural blood patch (EBP) is the treatment of choice when initial conservative managements are ineffective. We reported a patient with SIH diagnosed by using magnetic resonance imaging and radionuclide cisternography. Acute rebound intracranial hypertension developed after EBP and was successfully treated with intravenous osmotic agent.  相似文献   
20.
The brainstem abscess of a nine-year-old girl with tetralogy of Fallot was cured after six weeks of parenteral antibiotic therapy, without surgical intervention. Serial studies of brainstem auditory evoked potentials were undertaken until the patient was clinically normal. To the authors' knowledge, this is only the second medically cured case reported in the literature, and it is the first case studied with serial brainstem auditory evoked potentials. If the clinical status allows, medical treatment of a brainstem abscess with appropriate antibiotics could be tried before surgical intervention such as stereotactic aspiration for reducing the mass.  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