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   18877篇
  免费   1529篇
  国内免费   44篇
耳鼻咽喉   171篇
儿科学   586篇
妇产科学   393篇
基础医学   2767篇
口腔科学   290篇
临床医学   1819篇
内科学   4007篇
皮肤病学   228篇
神经病学   1668篇
特种医学   815篇
外科学   3062篇
综合类   289篇
一般理论   21篇
预防医学   1577篇
眼科学   405篇
药学   1143篇
  1篇
中国医学   17篇
肿瘤学   1191篇
  2023年   75篇
  2022年   98篇
  2021年   339篇
  2020年   218篇
  2019年   361篇
  2018年   469篇
  2017年   317篇
  2016年   331篇
  2015年   386篇
  2014年   571篇
  2013年   759篇
  2012年   1283篇
  2011年   1238篇
  2010年   715篇
  2009年   619篇
  2008年   1092篇
  2007年   1179篇
  2006年   1158篇
  2005年   1116篇
  2004年   1075篇
  2003年   1034篇
  2002年   977篇
  2001年   280篇
  2000年   268篇
  1999年   254篇
  1998年   216篇
  1997年   202篇
  1996年   183篇
  1995年   143篇
  1994年   140篇
  1993年   155篇
  1992年   146篇
  1991年   191篇
  1990年   144篇
  1989年   152篇
  1988年   137篇
  1987年   132篇
  1986年   141篇
  1985年   131篇
  1984年   121篇
  1983年   138篇
  1982年   121篇
  1981年   121篇
  1980年   108篇
  1979年   143篇
  1978年   111篇
  1977年   90篇
  1975年   86篇
  1974年   79篇
  1973年   74篇
排序方式: 共有10000条查询结果,搜索用时 593 毫秒
41.
The present paper outlines the development and evaluation of an allocation committee to distribute community placements on an equitable basis between universities. Although based on our experience in South Australia with the University Placement Allocation Committee (UPAC), the primary goal is to outline the steps that would be useful if placement coordinators at other universities in Australia decided to establish and maintain an allocation committee. A survey of field supervisors was also conducted and field supervisors endorsed UPAC as a constructive mechanism for allocating community placements.  相似文献   
42.
Galega officinalis L (goatsrue), a plant introduced from Europe and found in abundance in northern Utah, was tested for toxicity in ewes (Ovis aries). Clinical signs of poisoning induced by doses as small as 0.8 g of dried plant/kg body weight/day included dyspnea, anoxia, and foaming nasal discharge. Pathologic signs in animals that died following overdose of the plant included severe hydrothorax, generalized lung congestion, foamy exudate in bronchioles and trachea, epicardial and endocardial petechiation, and pericardial effusion in severely affected ewes. Microscopic lesions included a severe diffuse alveolar and interlobular edema. No significant alterations in blood constituents were observed in treated animals. Ewes administered the plant on several consecutive days developed an apparent adaptation to the toxin of the plant and were thereby able subsequently to tolerate levels 5-10 times the pre-treatment lethal dose with no discernible adverse clinical or pathological effects.  相似文献   
43.
A phase III multicenter study was conducted in 89 patients with known intracranial vascular lesions to evaluate an extracellular gadolinium contrast agent, gadoteridol, for intracranial magnetic resonance (MR) angiography. The pre- and postcontrast MR angiograms of 82 patients were evaluated by the unblinded investigators and by two blinded readers (A and B) for visualization of lesions; arterial and venous anatomy; extent, size, and number of lesions; and disease classification. The unblinded readers indicated that lesions were visualized better on postcontrast images in the following categories: venous anatomy, 87 (81%) of 107 lesions; arterial anatomy, 43 lesions (40%); and extent or size of lesions, 38 lesions (36%). In 29 (35%) of 82 patients, the unblinded readers determined that enhanced MR angiography provided more diagnostic information than unenhanced MR angiography. The blinded readers determined that enhanced MR angiography provided more information for visualization of vascular anatomy in more than 60% of cases. The additional information provided with gadoteridol would have changed the diagnosis in nine (8%) of 107 lesions seen by the unblinded readers, 11 (12%) of 90 lesions seen by reader A, and three (3%) of 93 lesions seen by reader B. The results confirm that the use of gadoteridol improves the visualization of intracranial vascular lesions with MR angiography. The authors conclude that development of new postprocessing algorithms will improve the utility of contrast-enhanced MR angiography.  相似文献   
44.
45.
There is an ongoing debate in nurse education concerning the role and delivery of the biological sciences in the nursing curriculum. One of the fundamental questions raised by this debate asks how best can teachers impart biological knowledge in a manner that can be readily applied by students and qualified nurses to inform their clinical practice. This paper will include a discussion of some of the features of pre-registration education that may have influenced the manner in which biological sciences are perceived, taught and used by nurses. It will be argued that nursing may have developed a form of incomplete holism and that this may be in part responsible for the challenges that remain to be met within this area of the nursing curriculum. As a response to incomplete holism an innovative approach within pre-registration education will be introduced. This development involves the use of linked teaching sessions which aim to develop the analytical skills necessary to apply physiological knowledge to nursing practice.  相似文献   
46.
47.
This review critically appraises the evidence on the benefits and costs of the available treatments for gastroesophageal reflux disease (GERD) and concludes that antireflux surgery has no clear advantages over medical therapy for efficacy of healing, prevention of complications, safety, side effects, and cost. Indeed, medical therapy is safer and, probably, more cost-effective. Compared with medically treated patients, those who have successful fundoplication may be less inconvenienced by GERD because they are less likely to need to take pills on a daily basis. The patient and physician must judge whether that benefit justifies the risks of surgery for a benign condition. There is not yet sufficient data available on the endoscopic antireflux procedures to make meaningful conclusions regarding their safety and efficacy.  相似文献   
48.
49.
50.
One hundred sixty-eight adult siblings and parents from affected and control families were tested for ERP characteristics using two tasks involving an auditory oddball paradigm. Significant within family differences among affected families suggest that risk for developing alcoholism may be seen even in adult subjects who have had experience consuming alcohol. Further, analysis of quantity and recency of drinking in the past seven days were not correlated with either amplitude or latency of P300, suggesting that the within-family differences observed reflect relative risk for developing alcoholism rather than experience with alcohol.  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