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   48557篇
  免费   3696篇
  国内免费   192篇
耳鼻咽喉   570篇
儿科学   1021篇
妇产科学   992篇
基础医学   6685篇
口腔科学   1028篇
临床医学   4955篇
内科学   10233篇
皮肤病学   1085篇
神经病学   4646篇
特种医学   1977篇
外国民族医学   2篇
外科学   8699篇
综合类   491篇
一般理论   77篇
预防医学   2825篇
眼科学   942篇
药学   2849篇
中国医学   76篇
肿瘤学   3292篇
  2023年   437篇
  2022年   752篇
  2021年   1739篇
  2020年   1036篇
  2019年   1371篇
  2018年   1550篇
  2017年   1052篇
  2016年   1223篇
  2015年   1413篇
  2014年   1908篇
  2013年   2235篇
  2012年   3654篇
  2011年   3574篇
  2010年   1989篇
  2009年   1773篇
  2008年   2812篇
  2007年   2872篇
  2006年   2672篇
  2005年   2512篇
  2004年   2330篇
  2003年   2114篇
  2002年   1952篇
  2001年   535篇
  2000年   518篇
  1999年   549篇
  1998年   440篇
  1997年   349篇
  1996年   267篇
  1995年   253篇
  1994年   213篇
  1993年   222篇
  1992年   368篇
  1991年   342篇
  1990年   314篇
  1989年   273篇
  1988年   260篇
  1987年   245篇
  1986年   235篇
  1985年   264篇
  1984年   218篇
  1983年   206篇
  1982年   171篇
  1981年   159篇
  1980年   172篇
  1979年   183篇
  1978年   154篇
  1977年   140篇
  1976年   141篇
  1974年   145篇
  1972年   121篇
排序方式: 共有10000条查询结果,搜索用时 812 毫秒
81.
In his autobiography, Dr. Wilder Penfield relates the medical history of his sister, Mrs. Ruth Inglis, who developed a right frontal oligodendroglioma. Penfield performed the initial craniotomy on her, and after her death, reported the case in a paper on frontal lobe function in humans. Although Penfield has provided more than adequate information on certain aspects of his sister's illness, little has been published concerning her subsequent operation performed by Dr. Harvey Cushing at the Peter Bent Brigham Hospital. We feel this case is significant for several reasons. First, it sheds some light on Penfield's personal relationship with Cushing and his sister; it also shows the deep interest that Dr. Cushing took in his patients. Second, this case nicely illustrates how Cushing used his postoperative drawings to make his operative notes more precise. Finally, we see a sample of the work done by Dr. Louise Eisenhardt as pathologist at the Peter Bent Brigham Hospital.  相似文献   
82.
83.
Forty-four isolates of Acinetobacter calcoaceticus var anitratus collected during hospital outbreaks were studied using polyacrylamide gel electrophoresis (PAGE), plasmid analysis, antibiograms and biochemical tests to determine their degree of similarity. Reproducibility tests were also carried out on the PAGE and biochemical techniques to determine their validity when used to compare bacteria of the same type isolated intermittently. PAGE data was analysed densitometrically and isolates compared using a similarity matrix. All methods were able to subdivide the isolates, but results did not always correlate well between methods. Reproducibility data indicated that careful attention to technique is required when organisms are examined by PAGE sequentially. Results suggest that no single biotyping technique is likely to be adequate and that electrophoretic, biochemical and antibiogram data may complement one another and other epidemiological data in the typing of these organisms.  相似文献   
84.
1. Second messenger responses to natriuretic peptides were studied in guinea-pig cerebellar slices by use of radioactive precursors. 2. The rank order of potency of the different natriuretic peptides in generating [3H]-guanosine 3':5'-cyclic monophosphate (cyclic GMP) was atrial natriuretic peptide (ANP) > brain natriuretic peptide (BNP) >> C-type natriuretic peptide (CNP) with EC50 values of 19.5 +/- 8.8 nM for ANP and 169 +/- 41 nM for BNP. CNP induced [3H]-cyclic GMP accumulation only at concentrations greater than 1 microM. 3. An additive response to ANP (1 microM) was observed in the presence of the adenosine receptor agonist, 5'-N-ethylcarboxamidoadenosine (NECA, 10 microM) or the soluble guanylyl cyclase activator, sodium nitroprusside (SNP, 100 microM) for [3H]-cyclic GMP accumulation. 4. ANP, BNP and CNP (all at 1 microM) failed to alter significantly either basal-, forskolin- (10 microM), isoprenaline- (100 microM), or NECA- (10 microM) induced [3H]-cyclic AMP generation. Natriuretic peptides also did not change the [3H]-cyclic AMP steady-state reached after 10 min of treatment with 10 microM forskolin. 5. Natriuretic peptides failed to elicit significant accumulation of [3H]-inositol phosphates at concentrations up to 10 microM. 6. These data are consistent with the presence of ANPA, rather than ANPB or clearance receptors (C-receptors), linked to second messenger cascades in guinea-pig cerebellar slices.  相似文献   
85.
The stability of phenytoin in blood collected in plain and serum separator tubes (SSTs) was investigated under simulated storage and transport conditions. The drug was generally more stable in plain collection tubes than in SSTs. No degradation occurred in plain red-top tubes or in refrigerated SSTs, but clinically significant degradation was present in SSTs stored at room temperature (25 degrees C) and at elevated temperature (32 degrees C) 24 h after collection. The mean loss was 17.9% at 25 degrees C and 25.9% at 32 degrees C. It is recommended that if blood is to be transported or stored in SSTs, the samples be refrigerated unless assay can be performed within 8 h.  相似文献   
86.
87.
88.
89.
90.
Revision endoscopic frontal sinus surgery with surgical navigation.   总被引:9,自引:0,他引:9  
BACKGROUND: Revision surgery of the frontal sinus remains one of the most difficult operations for the endoscopic surgeon. Most agree that knowledge and recognition of its complex anatomy and sparing of frontal recess mucosa are keys to a successful operation. The use of surgical navigation systems may allow for more precise dissections and greater rates of frontal recess patency. METHODS: Retrospective review of all patients undergoing revision endoscopic frontal sinus surgery with surgical navigation was performed with a minimum 24-month follow-up. RESULTS: Sixty-seven patients underwent revision endoscopic frontal sinus surgery with surgical navigation. The average follow-up was 32 months. Fifty-eight (86.6%) had a patent frontal recess and significant subjective improvement in symptoms. No patient underwent external frontal sinus obliteration, and there were no major complications. CONCLUSIONS: Endoscopic techniques with surgical navigation are effective in revision frontal sinus cases. The dissection of remnant agger nasi, obstructing frontal and supraorbital cells are necessary to widen the anterior-posterior as well as the medial-lateral dimensions of the recess. Computer navigational systems appear to serve as a valuable adjunct in preoperative planning and safe intraoperative dissection.  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