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   42125篇
  免费   3413篇
  国内免费   105篇
耳鼻咽喉   382篇
儿科学   1303篇
妇产科学   1067篇
基础医学   6455篇
口腔科学   570篇
临床医学   5684篇
内科学   7989篇
皮肤病学   757篇
神经病学   4359篇
特种医学   1231篇
外科学   4214篇
综合类   424篇
现状与发展   1篇
一般理论   36篇
预防医学   4341篇
眼科学   687篇
药学   2841篇
中国医学   51篇
肿瘤学   3251篇
  2023年   311篇
  2022年   474篇
  2021年   989篇
  2020年   654篇
  2019年   1033篇
  2018年   1207篇
  2017年   935篇
  2016年   1018篇
  2015年   1081篇
  2014年   1524篇
  2013年   1975篇
  2012年   3134篇
  2011年   3202篇
  2010年   1748篇
  2009年   1583篇
  2008年   2749篇
  2007年   2801篇
  2006年   2585篇
  2005年   2648篇
  2004年   2379篇
  2003年   2231篇
  2002年   2150篇
  2001年   566篇
  2000年   417篇
  1999年   505篇
  1998年   480篇
  1997年   404篇
  1996年   324篇
  1995年   306篇
  1994年   253篇
  1993年   234篇
  1992年   275篇
  1991年   271篇
  1990年   225篇
  1989年   247篇
  1988年   227篇
  1987年   234篇
  1986年   203篇
  1985年   181篇
  1984年   175篇
  1983年   123篇
  1982年   128篇
  1981年   122篇
  1980年   111篇
  1979年   104篇
  1978年   107篇
  1977年   105篇
  1976年   93篇
  1974年   108篇
  1973年   84篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
OBJECTIVE: Health systems throughout much of the world have been subject to 'reform' in recent years as countries have attempted to contain the rapidly rising costs of health care. Changes to hospital structures (restructuring) have been an important part of these reforms. A significant impact of current approaches to restructuring is the loss of, or changes to, nursing management roles and functions. SETTING: Australian hospitals PRIMARY ARGUMENT: Little evaluation has been undertaken to determine the impact of hospital structure and organisational restructuring on the nursing workforce. CONCLUSIONS: There is some indication that nurses have experienced a loss of key management positions, which may impact on their capacity to ensure that adequate and safe care is provided at the ward level.  相似文献   
52.
The Melanesians of the North Solomons are exposed to intense equatorial sunlight and yet have a very low incidence of skin cancer. This study reveals no proven cases of basal cell carcinoma in these people, and demonstrates the rarity of squamous cell carcinoma and melanoma arising in normal pigmented skin. Most, if not all squamous cell carcinomas, arise in skin damaged by tropical ulceration, burns or osteomyelitis. Melanoma arises from the unpigmented skin of the sole of the foot. North Solomon Islanders are very deeply pigmented. Presumably, dense cutaneous melanin in normal undamaged skin provides the highly effective protection against solar carcinogenesis which these people enjoy. Chronic or recurrent skin ulceration with subsequent repair, scarring and loss of pigment is the precursor to almost all non-melanoma skin cancer in these people. Most of these cancers could be prevented by split thickness skin grafting of chronic ulcers, and protection of ulcerated, depigmented and scarred skin from solar radiation.  相似文献   
53.
54.
55.
56.
Blalock-Taussig shunts (subclavian to pulmonary anastomoses) have remained the most effective palliation in cyanotic heart disease. Late complications are rare but can be devastating. The case of a 26-year-old female with tetralogy and an original Blalock shunt constructed at age four years is reported. Despite subsequent primary repair of the tetralogy and presumed ligation of the Blalock shunt, the patient succumbed to a fatal hemorrhage due to esophageal-arterial fistula involving the Blalock shunt. The circumstances leading to this dramatic outcome are outlined and discussed. It is important for cardiologists caring for congenital heart disease patients to be aware of the late complications of congenital heart surgery, and carry out the proper follow-up investigations.  相似文献   
57.
OBJECTIVES: To confirm the consistent effects on Doppler-measured aortic blood flow velocity waveform variables of alterations in left ventricular preload, afterload, and inotropy using pharmacologic and physiologic maneuvers. SETTING: Medical school laboratory. SUBJECTS: Healthy volunteers. INTERVENTIONS: Increasing infusion rates of dobutamine (1.25 to 5 micrograms/kg.min), esmolol (1.25 to 5 mg/min), phentolamine (1.25 to 5 mg/min), methoxamine (1.25 to 5 mg/min), metaraminol (1.25 to 5 mg/min), and placebo (1.25 to 5 mL of 0.9% saline/min) and increasing plasma removal (0.5 to 1 L) in awake, rested, supine subjects. MEASUREMENTS AND MAIN RESULTS: Ascending aortic blood flow was measured by the suprasternal Doppler approach allowing calculation of waveform variables of stroke distance and minute distance (linear measures of stroke volume and cardiac output), peak velocity, mean acceleration and flow time corrected for heart rate. An index of systemic vascular resistance was obtained by dividing mean systemic BP by the minute distance. Inotropic changes predominantly affected peak velocity and mean acceleration. Changes in preload mainly affected the flow time corrected for heart rate, whereas afterload changes had an intermediate effect. Unsuspected but subsequently confirmed hemodynamic effects were seen with esmolol and metaraminol. CONCLUSIONS: Aortic blood flow velocity waveform variables measured by Doppler ultrasound can be used to noninvasively follow changes in left ventricular preload, afterload, and inotropy.  相似文献   
58.
Experimental allergic encephalomyelitis (EAE) is an autoimmune inflammatory disease of the central nervous system (CNS). In particular in the CsA-induced chronic relapsing form (CREAE), pronounced demyelination occurs, in temporal association with relapses. It is still a matter of discussion which cell type ultimately is responsible for the actual process of demyelination. Macrophages, cytotoxic T lymphocytes and also astrocytes are possible candidates. In this short overview, the role of macrophages in the pathogenesis of EAE is discussed. It is shown that in particular, newly recruited macrophages play a crucial role in the generation of clinical signs. Possible mechanisms by which macrophages are involved in the pathogenesis of demyelinating diseases are presented.  相似文献   
59.
The establishment of a biorepository with linkage to clinical and epidemiologic data will provide an invaluable resource for cancer research, including studies of cancer etiology, progression, and prognosis, as well as development of biomarkers for early detection. Developing an infrastructure for a biorepository linked to clinical, pathologic, and epidemiologic data requires significant efforts in strategic planning for efficient means to ascertain, identify, and consent participants, as well as guidelines for blood collection, processing, and storage while maintaining participant privacy rights. In this report, we present an approach to developing a Data Bank and Biorepository at our own institution, with discussion of elements to be considered when establishing such a bank.  相似文献   
60.
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