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   22309篇
  免费   1283篇
  国内免费   196篇
耳鼻咽喉   172篇
儿科学   1253篇
妇产科学   326篇
基础医学   2638篇
口腔科学   383篇
临床医学   1382篇
内科学   3972篇
皮肤病学   454篇
神经病学   1464篇
特种医学   795篇
外国民族医学   5篇
外科学   3176篇
综合类   820篇
一般理论   4篇
预防医学   1492篇
眼科学   1123篇
药学   2165篇
  5篇
中国医学   312篇
肿瘤学   1847篇
  2023年   108篇
  2022年   260篇
  2021年   493篇
  2020年   317篇
  2019年   364篇
  2018年   450篇
  2017年   350篇
  2016年   419篇
  2015年   492篇
  2014年   709篇
  2013年   900篇
  2012年   1314篇
  2011年   1316篇
  2010年   795篇
  2009年   637篇
  2008年   1087篇
  2007年   1088篇
  2006年   1008篇
  2005年   961篇
  2004年   840篇
  2003年   841篇
  2002年   772篇
  2001年   633篇
  2000年   650篇
  1999年   586篇
  1998年   256篇
  1997年   228篇
  1996年   201篇
  1995年   189篇
  1994年   156篇
  1993年   161篇
  1992年   363篇
  1991年   392篇
  1990年   350篇
  1989年   393篇
  1988年   294篇
  1987年   308篇
  1986年   247篇
  1985年   274篇
  1984年   239篇
  1983年   208篇
  1982年   130篇
  1981年   119篇
  1979年   189篇
  1978年   124篇
  1975年   134篇
  1974年   143篇
  1973年   136篇
  1972年   123篇
  1971年   142篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
PurposeRegional nodal irradiation (RNI) improved disease-free survival by 3% to 5% in 2 large randomized trials, but this small absolute advantage relies on accurate contouring and dose delivery. We audited our network to determine compliance on regional nodal coverage, contouring, and dosimetric parameters with respect to accepted guidelines.Methods and MaterialsIn our network, we have established a clinical pathway for patients with node-positive breast cancer that guides indications for RNI and dosimetric goals. We reviewed records of 183 patients with nodal macrometastases after upfront surgery or involved nodes of any size after neoadjuvant chemotherapy. Radiation treatment plans were examined to determine lymph node volumes treated, whether nodes were contoured, quality of nodal contours, and whether target coverage and normal organ dosimetric constraints were met when RNI was delivered.ResultsDespite the presence of macrometastases on sentinel lymph node biopsy, no lymph nodes were treated in 2.2% (4 of 183). Of 179 patients who received nodal irradiation, 18 received radiation to axillary levels 1 and 2 only, and 161 patients received RNI. Overall, regional nodes were not treated despite strong indications in 7.6% (14 of 183). Treated nodes were not contoured for 2.2% (4 of 179), and lymph node contours were unacceptable in 15.4% (27 of 175). Of patients receiving RNI, 14.9% (24 of 161) did not have adequate nodal target volume coverage, mean heart dose was >4 Gy for 3.1% (5 of 161), and lung V20 Gy was >35% for 8.7% (14 of 161).ConclusionsAdherence to indications for regional nodal treatment was high, but nodes were either not contoured or had unacceptable contour quality in 18% of plans, and coverage was inadequate in 15%. Because the small disease-free survival advantage seen in trials may be decreased with these deviations, routine clinical practice requires detailed peer review to fully translate results of clinical trials.  相似文献   
5.
BACKGROUND: Penetrating injuries of the perineum are rare but very dangerous. Since the genitourinary and colorectal organs may be injured, how to evaluate surgical management of the injury is very important.METHODS: The present report presents a case of penetrating injury of the perineum by a wooden stick when the patient fell on the upright wooden stick from a tree. The three feet long stick entered the perineal region just left lateral to the anal opening. Upon reaching the thoracic cavity, it broke and only a foot stick was left in the subcutaneous plane. These injuries are potentially serious with risk of damage to multiple organs. Exploratory laprotomy was done, and bladder injury was repaired. The entry wound and the track of stick was thoroughly washed and allowed for secondary intention healing.RESULTS: The post operative period was uneventful and the patient recovered fully.CONCLUSION: Meticulous evaluation and surgical management of perineal injuries are the key to prevent devastating complications.  相似文献   
6.

Objective

Hypertonic saline (HTS) has potent immune and vascular effects. We assessed recipient pretreatment with HTS on allograft function in a porcine model of heart transplantation and hypothesized that HTS infusion would limit endothelial and left ventricular (LV) dysfunction following transplantation.

Methods

Heart transplants were performed after 6 hours of cold ischemic storage. Recipient pigs were randomized to treatment with or without HTS (7.5% NaCl) before cardiopulmonary bypass (CPB). Using a myograft apparatus, coronary artery endothelial-dependent (Edep) and -independent (Eind) relaxation was assessed. LV performance was determined using pressure-volume loop analysis. Pulmonary interleukin (IL)-2, IL-6, and tumor necrosis factor (TNF)-α expression was measured.

Results

Weaning from CPB and LV performance after transplantation were improved in HTS-treated animals. Successful weaning from CPB was greater in the HTS-treated hearts (8 of 8 vs 2 of 8; P < .05). Mean LV functional recovery was improved in the HTS-treated animals, as assessed by preload recruitable stroke work (65 ± 10% vs 27 ± 10%; P < .001) and end-systolic elastance (55 ± 7% vs 37 ± 4%; P < .001). Treatment with HTS resulted in improved Edep (mean maximum elastance [Emax], 56 ± 5% vs 37 ± 7%; P < .001) and Eind (mean Emax%, 77 ± 6% vs 52 ± 4%; P < .001) vasorelaxation compared with control. Pulmonary expression of IL-2, IL-6, and TNF-α increased following transplantation, whereas HTS therapy attenuated IL production (P < .001). Transplantation increased plasma TNF-α levels and LV TNF-α expression, whereas HTS prevented this up-regulation (P < .001).

Conclusions

Recipient HTS pretreatment preserves allograft vasomotor and LV function, and HTS therapy limits CPB-induced injury. HTS may be a novel recipient intervention to prevent graft dysfunction.  相似文献   
7.
目的:观察中西医结合治疗排卵障碍性不孕症的疗效。方法:82例按随机数字表法分为对照组和观察组各41例。两组均给予常规西药治疗,观察组加用腹针温阳法治疗。结果:受孕成功率观察组84.44%,对照组71.11%,两组比较差异有统计学意义(P<0.05)。观察组优质卵泡直径小于对照组(P<0.05),优质卵泡数量以及子宫内膜厚度均高于对照组(P<0.05)。两组卵巢动脉血流PI、RI、PSV与EDV指标均优于治疗前(P<0.05),且观察组各项指标均优于对照组(P<0.05)。结论:中西医结合治疗排卵障碍性不孕症可改善卵泡发育以及卵巢动脉血流指标,提高受孕率。  相似文献   
8.
9.
Endoscopic clips have been used mainly for control of gastrointestinal (GI) bleeding and occasionally for closure of GI perforations. However, closure of spontaneous esophageal perforation (Boerhaave's syndrome) by clipping has not been reported. We described successful non-surgical closure of spontaneous esophageal perforation by endoscopic clipping in a patient with bilateral pyopneumothorax and septicemia.  相似文献   
10.
Both ultrashort echo-time STEAM and MEGA-PRESS-edited spectroscopy were used to validate noninvasive quantification of vitamin C (ascorbate) in the developing rat brain, where changes in ascorbate concentration have been reported. Despite strong overlap with resonances from glutamine, glutamate, glutathione, and macromolecules, reliable quantification of ascorbate (Cramer-Rao lower bounds<0.2 micromol/g) by LCModel analysis of STEAM (TE=2 ms) spectra was possible at 9.4 T. Ascorbate concentrations quantified from the STEAM spectra were in very good agreement with concentrations calculated from fully resolved ascorbate resonances in MEGA-PRESS-edited spectra measured from identical volumes of interest. Ascorbate concentrations measured using STEAM decreased with increasing postnatal rat age, in agreement with published brain ascorbate concentrations measured in vitro using high-performance liquid chromatography (HPLC).  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