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   2189篇
  免费   124篇
  国内免费   8篇
耳鼻咽喉   46篇
儿科学   38篇
妇产科学   95篇
基础医学   164篇
口腔科学   72篇
临床医学   206篇
内科学   467篇
皮肤病学   46篇
神经病学   130篇
特种医学   79篇
外国民族医学   1篇
外科学   434篇
综合类   49篇
预防医学   132篇
眼科学   77篇
药学   193篇
  1篇
中国医学   11篇
肿瘤学   80篇
  2023年   16篇
  2022年   53篇
  2021年   88篇
  2020年   44篇
  2019年   59篇
  2018年   83篇
  2017年   56篇
  2016年   63篇
  2015年   81篇
  2014年   97篇
  2013年   119篇
  2012年   186篇
  2011年   162篇
  2010年   112篇
  2009年   105篇
  2008年   145篇
  2007年   132篇
  2006年   121篇
  2005年   124篇
  2004年   106篇
  2003年   65篇
  2002年   53篇
  2001年   22篇
  2000年   18篇
  1999年   23篇
  1998年   13篇
  1997年   9篇
  1996年   4篇
  1992年   5篇
  1990年   12篇
  1989年   5篇
  1988年   7篇
  1985年   14篇
  1984年   5篇
  1983年   8篇
  1980年   6篇
  1979年   5篇
  1978年   4篇
  1977年   6篇
  1976年   4篇
  1975年   5篇
  1974年   9篇
  1973年   9篇
  1972年   3篇
  1971年   5篇
  1970年   4篇
  1969年   10篇
  1968年   5篇
  1967年   7篇
  1966年   5篇
排序方式: 共有2321条查询结果,搜索用时 15 毫秒
1.
Ion-exchange adsorbers are widely used for radioisotope separation, as well as for the removal of hazardous fission products from aqueous waste prior to discharge to the environment. Inorganic exchangers are of particular interest because of their resistance to radiolytic damage and selectivity for specific fission products. Composite inorganic-organic adsorbers represent a group of inorganic ion exchangers modified by using binding organic material, polyacrylonitrile, for preparation of larger size particles with higher granular strength. At the same time, kinetics of ion exchange and sorption capacity of such composite adsorbers are not influenced by the binding polymer. The contents of active component in composite adsorber were varied over a very broad range of 5-95% of the dry weight of the composite adsorber, and tested for separation and concentration of various stimulated wastes. Three different inorganic sorbents, granular hexacyanoferrate-based ion exchanger, were developed for the removal of Cs and Co ions from waste solutions containing different complexing agents as detergents. Radiation and thermal stability studies show that these adsorbents can be used for medium-active waste treatment.  相似文献   
2.
The therapeutic response to treatment of lumbar disk herniation with chymopapain chemonucleolysis is significantly influenced by the criteria used for patient selection. Although careful clinical selection of patients reduces the frequency of treatment failure, some patients do not achieve satisfactory relief of pain with chemonucleolysis. In an attempt to identify objective pretreatment radiographic findings that might refine selection criteria and further reduce the failure rate of chemonucleolysis, a retrospective correlation of pretreatment radiographs and clinical responses was made of 200 consecutive chemonucleolysis patients. Marked improvement in sciatica occurred in 79.9% and 79.3% of patients at early and late follow-up, respectively. There was a significantly higher response rate, however, in patients who had definite radiographic evidence of focal disk herniation and in those patients with definite radiographic evidence of nerve-root compression (marked nerve-root deviation, nerve-root flattening or edema, root-sleeve amputation) by disk material. Those patients with a preinjection disk height greater than the mean had a slightly better response rate (91.1%) than those whose disk height was smaller than the mean (80.0%). Most cases of treatment failure could be attributed to an incorrect radiographic diagnosis, treatment of patients with equivocal diagnostic studies, the presence of "free" disk fragments, and causes of nerve-root compression unresponsive to chymopapain.  相似文献   
3.
4.
Pain during sexual activity and ejaculation are the unspoken long-term complications of groin hernia repair. Laparoscopic surgical techniques are associated with decreased post-operative pain and earlier return to daily activities, but its effect on these complications is unclear. This study aims to investigate the effect of transabdominal preperitoneal repair (TAPP) on de-novo pain during sexual intercourse and ejaculation and to compare with open repair. For this reason, two groups were determined according to the surgical technique: the Lichtenstein repair and the TAPP groups and a questionnaire was sent to the patients a minimum of 6 months following the surgery. A total of 317 patients included, as 115 in TAPP and 202 in Lichtenstein repair group. No significant difference was observed concerning pre-operative pain during sexual activity and ejaculation in both groups (p = .75, p = .56). Following the surgery, the number of patients experiencing painful sexual activity was significantly higher in the Lichtenstein repair group compared to the TAPP group (19.3% vs. 11.3%, respectively, p = .03). The post-operative painful ejaculation rate was also significantly lower for the TAPP group (p = .04). The lower rates of post-operative dysejaculation and pain during sexual activity can be achieved with the advantage of laparoscopic surgery.  相似文献   
5.
During a six month period, one hundred patients presenting with the primary complaint of hoarseness, in the out- patients department of otolaryngology at Safdarjung Hospital New Delhi were taken up fot the study Fach patient after being subjected to a detailed history- taking and examination, including a Fibreoptic Laryngoscopy was then put into one of ten categories on the basis of the ultimate diagnosis Functional voice disorders, forming the largest category with 51%, included lesions such as vocal nodules and polyps, which are secondary to vocal abuse A detailed study of the various types of functional voice disorders along with factors such as male female ratio and associated contributory factors was done the efficacy of the Fibreoptic laryngoscope as a diagnostic tool was also assessed  相似文献   
6.
Cardiovascular (CV) toxicities of the Bruton tyrosine kinase (BTK) inhibitor ibrutinib may limit use of this effective therapy in patients with chronic lymphocytic leukemia (CLL). Acalabrutinib is a second-generation BTK inhibitor with greater BTK selectivity. This analysis characterizes pooled CV adverse events (AE) data in patients with CLL who received acalabrutinib monotherapy in clinical trials (clinicaltrials gov. Identifier: NCT02029443, NCT02475681, NCT02970318 and NCT02337829). Acalabrutinib was given orally at total daily doses of 100–400 mg, later switched to 100 mg twice daily, and continued until disease progression or toxicity. Data from 762 patients (median age: 67 years [range, 32–89]; median follow-up: 25.9 months [range, 0–58.5]) were analyzed. Cardiac AE of any grade were reported in 129 patients (17%; grade ≥3, n=37 [5%]) and led to treatment discontinuation in seven patients (1%). The most common any-grade cardiac AE were atrial fibrillation/flutter (5%), palpitations (3%), and tachycardia (2%). Overall, 91% of patients with cardiac AE had CV risk factors before acalabrutinib treatment. Among 38 patients with atrial fibrillation/flutter events, seven (18%) had prior history of arrhythmia or atrial fibrillation/flutter. Hypertension AE were reported in 67 patients (9%), 43 (64%) of whom had a preexisting history of hypertension; no patients discontinued treatment due to hypertension. No sudden cardiac deaths were reported. Overall, these data demonstrate a low incidence of new-onset cardiac AE with acalabrutinib in patients with CLL. Findings from the head-to-head, randomized trial of ibrutinib and acalabrutinib in patients with high-risk CLL (clinicaltrials gov. Identifier: NCT02477696) prospectively assess differences in CV toxicity between the two agents.  相似文献   
7.
The aim of this study was to examine prenatal diagnosis of double-outlet right ventricle (DORV)-associated anomalies and prognosis of each case. Medical records were reviewed of fetuses with DORV who had fetal echocardiography at our institution from 2002 to 2006. Pre- and postnatal diagnosis and outcome were compared and evaluated. Twenty-one fetuses were diagnosed with DORV. The pregnancy was terminated in seven cases. Three cases had chromosomal abnormalities; three cases, hypoplastic left ventricle; and one case, encephalocele. Accurate prenatal diagnosis of the ventricular septal defect, outflow obstruction, and great artery relationship was achieved in 14 of 16 cases (87.5%). Only 2 of 13 live-born cases survived beyond 6 months. The overall prognosis for fetuses with DORV is poor. DORV is found in fetuses with a huge spectrum of associated cardiac and extracardiac anomalies. Careful assessment by fetal echocardiography can determine important anatomic details with adequate correctness for precise counseling.  相似文献   
8.
9.
Rational modification of molecular structure by incorporating electron donating groups can play a potential role for designing aggregation induced emission (AIE) active fluorescent probes. Based on this principle, fluorescent probes (1a–c) were synthesized, and they displayed excellent aggregation induced emission (AIE) behavior in a H2O/DMF (4 : 1, v/v) mixture due to restrictions in intramolecular charge transfer (ICT). As a comparison, probe 1d was synthesized by installing an electron withdrawing (–NO2) group that surprisingly quenched the aggregation behaviour. Additionally, AIE active probes 1a–c displayed a highly sensitive dual channel (fluorometric and colorimetric) response towards rapid detection of CN, which is an active toxic material. Probes 1a–c showed selectively enhanced fluorescence emission behavior towards CN with detection limits of 1.34 ppb, 1.38 ppb, and 1.54 ppb, respectively. The sensing mechanism involves Michael type adduct formation due to the nucleophilic addition reaction of cyanide with probes and was confirmed through 1H NMR titration experiments. In contrast, probe 1d containing an electron withdrawing moiety showed insensitivity towards CN. Therefore, this study provides the efficient strategy to induce AIE character in fluorescent probes and expands the mechanistic approach toward the sensing of toxic CN.

Rational modification of molecular structure by incorporating electron donating groups can play a potential role for designing aggregation induced emission (AIE) active fluorescent probes.  相似文献   
10.
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