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   519645篇
  免费   32958篇
  国内免费   24519篇
耳鼻咽喉   4361篇
儿科学   10254篇
妇产科学   7967篇
基础医学   57515篇
口腔科学   7681篇
临床医学   60124篇
内科学   82109篇
皮肤病学   4003篇
神经病学   35266篇
特种医学   22247篇
外国民族医学   221篇
外科学   64690篇
综合类   58325篇
现状与发展   83篇
一般理论   30篇
预防医学   39609篇
眼科学   12591篇
药学   44834篇
  363篇
中国医学   20081篇
肿瘤学   44768篇
  2024年   1069篇
  2023年   5252篇
  2022年   13667篇
  2021年   17125篇
  2020年   12831篇
  2019年   11376篇
  2018年   32807篇
  2017年   27236篇
  2016年   28694篇
  2015年   16320篇
  2014年   20029篇
  2013年   17783篇
  2012年   31880篇
  2011年   48666篇
  2010年   36196篇
  2009年   25443篇
  2008年   38121篇
  2007年   40285篇
  2006年   19394篇
  2005年   20476篇
  2004年   15030篇
  2003年   14956篇
  2002年   11654篇
  2001年   8291篇
  2000年   9139篇
  1999年   9489篇
  1998年   5800篇
  1997年   5831篇
  1996年   4520篇
  1995年   4094篇
  1994年   3379篇
  1993年   2199篇
  1992年   2899篇
  1991年   2547篇
  1990年   2275篇
  1989年   1961篇
  1988年   1627篇
  1987年   1406篇
  1986年   1148篇
  1985年   958篇
  1984年   555篇
  1983年   397篇
  1982年   271篇
  1981年   244篇
  1980年   228篇
  1979年   226篇
  1978年   91篇
  1977年   93篇
  1974年   124篇
  1973年   88篇
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
931.
Conclusion In the year 2003 there is no “one best bariatric operation” for every severely obese patient. The choice of operation must be tailored to each individual patient’s needs and wishes. For the superobese patient, the patient diagnosed with intestinal metaplasia of the stomach, and for those patients who do not wish to undergo the severe dietary restrictions imposed by the RNY-GB, the BPD-DS is a valuable surgical option.  相似文献   
932.
933.
In 1998, an epithermal neutron test beam was designed and constructed at the Tsing Hua Open-Pool Reactor (THOR) for the purpose of preliminary dosimetric experiments in boron neutron capture therapy (BNCT). A new epithermal neutron beam was designed at this facility, and is currently under construction, with clinical trials targeted in late 2004. Depth dose-rate distributions for the THOR BNCT test beam have been measured by means of activation foil and dual ion chamber techniques. Neutron and structure-induced gamma spectra measured at the test beam exit were configured into a source function for the Monte Carlo-based treatment planning code NCTPlan. Dose-rate scaling factors (DRSFs) were determined to normalize computationally derived dose-rate distributions with experimental measurements in corresponding mathematical and physical phantoms, and to thus enable accurate treatment planning using the NCTPlan code. A similar approach will be implemented in characterizing the new THOR epithermal beam in preparation for clinical studies. This paper reports the in-phantom calculated and experimental dosimetry comparisons and derived DRSFs obtained with the THOR test beam.  相似文献   
934.
Depressive symptoms in older adults are common, but the minority of elderly meet criteria for major depressive disorder. This has led to confusion regarding the recognition of diagnosis, approach to treatment, and monitoring of outcomes in this needy population. Few depressed older adults are willing to seek treatment from psychiatrists or mental health specialists. Treatment approaches to the depressive spectrum of disorders in late life, which encompasses major and minor depressive disorder, dysthymic disorder, and mood disorders related to medical conditions, must include evidence-based algorithms that can be delivered in a variety of health care settings. Several recent multisite trials have advanced the use of collaborative care models and the systematic stepwise approach to the treatment of depression and anxiety states in older adults. This offers the ability to provide effective treatment of depression for older adults, consistent with current guidelines, in primary care and specialized health care settings.  相似文献   
935.
936.
937.
938.
目的 :了解高原康胶囊对快速进入高原者血浆醛固酮 (Aldosterone ,ALD)、血管紧张素II(AngiotensinII ,AII)及水负荷的影响及意义。方法 :将 80名由平原快速进入高原的新兵随机分为实验组 4 0名 ,对照组 4 0名 ,实验组于平原登机前开始给予口服高原康胶囊 ,连服 3日 ,对照组给予安慰剂 ,两组均于进入高原的前 1天及进入高原的第 3天午给予水负荷实验 ,并对饮水前血浆ALD、AII及饮水后 15 0min内各时间段的尿量及两组进入高原后 7天内急性高原病 (Acutehighal titudediseaes ,AHAD)的发病率进行对照比较。结果 :对照组进入高原后与平原相比血浆ALD、AII显著升高 ,水负荷实验 6 1min~ 15 0min各时间段的尿量及相应时间的总尿量与平原时相应各时间段的尿量及相应时间的总尿量相比则显著减少 (P <0 0 5~ 0 0 0 1) ,而实验组则无显著变化 (P >0 0 5 ) ;进入高原后实验组与对照组相比水负荷实验 6 1min~ 90min的尿量及 12 0min、15 0min的尿总量则显著多于对照组 (P <0 0 5 ) ;血浆ALD、AII及AHAD发病率则显著低于对照组 (P <0 0 5~ 0 0 0 1)。结论 :高原康胶囊能显著降低快速进入高原者的血浆ALD、AII ,通过对水负荷调节的影响减少机体的钠水潴留 ,从而防止快速进入高原者AHAD的发生 ,可用于大批快  相似文献   
939.
940.
Background: As in inhaled isoflurane anesthesia, when isoflurane lipid emulsion (ILE; 8%, vol/vol) is intravenously administered, the primary elimination route is through the lungs. This study was designed to determine the minimum alveolar concentration (MAC) and the time course of washout of isoflurane for intravenously infused ILE by monitoring end-tidal isoflurane concentration.

Methods: Twelve healthy adult mongrel dogs were assigned randomly to an intravenous anesthesia group with 8% ILE or to an inhalation anesthesia group with isoflurane vapor. An up-and-down method and stimulation of tail clamping were used to determine MAC of 8% ILE by intravenous injection in the intravenous anesthesia group and MAC by the inhaled approach in the inhalation anesthesia group, respectively. Isoflurane concentration and partial pressure in end-tidal gas, femoral arterial blood, and jugular venous blood were measured simultaneously just before each tail clamping and during washout.

Results: The induction time in the intravenous anesthesia group (105 +/- 24 s) was shorter than that in the inhalation anesthesia group (378 +/- 102 s; P < 0.01). MAC of 8% ILE by intravenous injection (1.12 +/- 0.18%) was significantly less than MAC by the inhaled approach (1.38 +/- 0.16%; P < 0.05). No significant difference was found between the two groups in the time course of washout of isoflurane.  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