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   1989篇
  免费   143篇
  国内免费   50篇
耳鼻咽喉   4篇
儿科学   27篇
妇产科学   216篇
基础医学   191篇
口腔科学   22篇
临床医学   188篇
内科学   177篇
皮肤病学   19篇
神经病学   47篇
特种医学   74篇
外科学   360篇
综合类   263篇
预防医学   102篇
眼科学   8篇
药学   392篇
  1篇
中国医学   63篇
肿瘤学   28篇
  2024年   3篇
  2023年   14篇
  2022年   40篇
  2021年   64篇
  2020年   60篇
  2019年   46篇
  2018年   54篇
  2017年   71篇
  2016年   70篇
  2015年   54篇
  2014年   119篇
  2013年   141篇
  2012年   102篇
  2011年   111篇
  2010年   91篇
  2009年   103篇
  2008年   88篇
  2007年   83篇
  2006年   110篇
  2005年   102篇
  2004年   66篇
  2003年   67篇
  2002年   73篇
  2001年   44篇
  2000年   35篇
  1999年   26篇
  1998年   21篇
  1997年   24篇
  1996年   27篇
  1995年   23篇
  1994年   18篇
  1993年   17篇
  1992年   23篇
  1991年   16篇
  1990年   16篇
  1989年   10篇
  1988年   13篇
  1987年   12篇
  1986年   12篇
  1985年   26篇
  1984年   19篇
  1983年   12篇
  1982年   19篇
  1981年   11篇
  1980年   9篇
  1979年   3篇
  1976年   2篇
  1975年   5篇
  1974年   2篇
  1966年   2篇
排序方式: 共有2182条查询结果,搜索用时 15 毫秒
21.
目的 探讨滤膜法和涂抹法检测血液透析相关用水微生物的效果,为选择合适的检测方法提供依据。方法 回顾性收集某三级甲等综合性医院2018年1-12月同时采用滤膜法和涂抹法检测血液透析相关用水微生物的结果,对比分析滤膜法和涂抹法检测细菌检出率、单位菌落数、超干预值检出率和微生物合格率。结果 共收集274份血液透析相关用水微生物检测结果,其中透析液131份,反渗水39份,B浓缩液(下简称B液)14份,置换液34份,其他透析用水56份。滤膜法细菌检出率均高于涂抹法,其中透析液、反渗水、置换液、其他透析用水标本使用两种方法的细菌检出率比较,差异有统计学意义(均P<0.05)。透析液、B液、其他透析用水标本单位菌落数滤膜法数值上低于涂抹法,但仅其他透析用水标本使用两种方法检测结果单位菌落数差异有统计学意义(t=-3.011,P=0.004)。超干预值检出率其他透析用水滤膜法低于涂抹法,差异有统计学意义(χ2=6.596,P=0.010)。置换液、反渗水标本微生物合格率滤膜法数值上低于涂抹法,但仅置换液标本微生物合格率差异有统计学意义(χ2=18.987,P<0.001)。结论 滤膜法检出细菌的能力高于涂抹法,但其在血液透析相关用水微生物检测中存在一定局限性,除用于置换液比较适合外,应用在其余血液透析相关用水微生物的检测效果并不优于涂抹法。  相似文献   
22.
Clomiphene, a selective oestrogen receptor modulator, has been utilised in managing male sub-fertility since 1967. Numerous controlled and uncontrolled studies have been published regarding the efficacy of clomiphene citrate in male sub-fertility cohorts. Although the primary intention of treating men with clomiphene citrate is to improve sperm parameters and testosterone levels, some studies have reported paradoxical decline in semen parameters. The information available on decline in sperm parameters following treatment with clomiphene is sparse. We conducted a systemic review using PubMed, Embase, Cochrane Library and Scopus databases for original studies reporting adverse effects of clomiphene citrate therapy on sperm parameters. This systematic review includes 384 men from 11 different studies that reported adverse effects of clomiphene citrate therapy. Of the men included in these studies, 19%, 21%, 17% and 24% of clomiphene-treated men demonstrated a decrease in sperm count, concentration, motility and total motile sperm count respectively. In up to 17% of patients, deterioration of semen parameters did not recover following discontinuation of therapy. In the future, more studies should report on this aspect so the magnitude of this effect can be more clearly understood.  相似文献   
23.
In peritoneal dialysis (PD), a cloudy dialysate is an alarming finding. Bacterial peritonitis is the most common cause, however, atypical infections and non‐infectious causes must be considered. A 46‐year‐old man presented with asthenia, paraesthesia, foamy urine and hypertension. Laboratory testing revealed severe azotaemia, anaemia, hyperkalaemia and nephrotic‐range proteinuria. Haemodialysis was started through a central venous catheter. Later, due to patient preference, a Tenckhoff catheter was inserted. Conversion to PD occurred 3 weeks later, during hospitalization for a presumed central line infection. A month later, the patient was hospitalized for neutropenic fever. He was diagnosed an acute parvovirus infection and was discharged under isoniazid for latent tuberculosis. Four months later, the patient presented with fever and a cloudy effluent. Peritoneal fluid (PF) cytology was suggestive of infectious peritonitis, but the symptoms persisted despite antibiotic therapy. Bacterial and mycological cultures were negative. No neoplastic cells were detected. Mycobacterium tuberculosis eventually grew in PF cultures, despite previous negative molecular tests. Directed therapy was then initiated with excellent response. Thus, facing a cloudy effluent, one must consider multiple aetiologies. Diagnosis of peritoneal tuberculosis is hampered by the lack of highly sensitive and specific exams. Here, diagnosis was only possible due to positive mycobacterial cultures.  相似文献   
24.
BACKGROUND: Adding clomiphene citrate (CC) to FSH for controlled ovarian stimulation (COS) decreases FSH dose required for optimum stimulation. However, because of its anti-estrogenic effects, CC may be associated with lower pregnancy rates offsetting the FSH-dose reduction benefit. Previously, we reported the success of aromatase inhibition in inducing ovulation without antiestrogenic effects. METHODS: A prospective pilot study that included women with unexplained infertility undergoing COS and intrauterine insemination. Thirty-six women received the aromatase inhibitor letrozole + FSH, 18 women received CC + FSH and 56 women received FSH only. Each woman received one treatment regimen in one treatment cycle. All patients were given recombinant or highly purified FSH (50-150 IU/day) starting on day 3 to 7 until day of hCG. RESULTS: The FSH dose needed was significantly lower in letrozole + FSH and CC + FSH groups compared with FSH-only without a difference in number of follicles >1.8 cm. Pregnancy rate was 19.1% in the letrozole + FSH group, 10.5% in the CC + FSH group and 18.7% in the FSH-only group. Both pregnancy rate and endometrial thickness were significantly lower in CC + FSH group compared with the other two groups. Estradiol (E2) levels were significantly lower in the letrozole + FSH group compared with the other two groups. CONCLUSIONS: Similar to CC, aromatase inhibition with letrozole reduces FSH dose required for COS without the undesirable antiestrogenic effects sometimes seen with CC.  相似文献   
25.
全血活化凝血时间在局部枸橼酸盐抗凝血透中的应用   总被引:1,自引:0,他引:1  
目的:开展局部枸橼酸抗凝血液透析,监控枸橼酸盐的输注量;方法:采用全血活化凝血时间(ACT)监测患者的凝血状态;结果:基础ACT值为110.5±10.09s;透析结束时动脉端ACT值为115.3±11.61s,与基础值相比无明显差异(P>0.05);透析结束时静脉端ACT值为146.6±30.35s,与基础值相比有显著差异(P<0.05),枸橼酸钠输注速度为30~40ml/h;结论:静脉端ACT值较基础值延长30%,枸橼酸盐能在体外循环达到有效抗凝效果,不会引起出血并发症  相似文献   
26.
A bloodless technique of evaluating protein catabolic rate (PCR) and KT/V (K, clearance; T, dialysis time; V, urea distribution volume) in hemodialysis patients is presented based on serial measurement of urea in the dialysate effluent stream. PCR follows from equating urea generation and urea removal over a 7 day cycle, changes in body stores being comparatively negligible: PCR = 0.026 [U1 + U2 + U3]/BWdry + 0.17, where U1 is the amount of urea in mmol appearing in the dialysate for each session in the 7 day period. KT/V is obtained from the slope of the natural logarithm of spent dialysate urea concentration-time plot: KT/V = [- slope.T + 3.delta BW/BWdry]/[1 - 0.01786.T(hr], where delta BW = amount ultrafiltered in liters. The dialysate-based approach was validated and compared with conventional urea kinetic modeling (UKM) for 17 patients studied for three consecutive dialyses. The dialysate-based and UKM values of PCR agreed well when in vivo clearance values based on total dialysate collection were used for UKM. KT/V values agreed poorly on a session-by-session basis but were nearly equivalent when averaged for the three dialyses of the week. These findings lay the foundation for UKM automation with a urea sensor in the effluent dialysate stream.  相似文献   
27.
Summary In idiopathic recurrent calcium urolithiasis (RCU) in men (n=37) the metabolic effects of oral tripotassium citrate (PC) were investigated in a longitudinal field study. The patients were either normo- (n=22) or hypocitraturic (n=15). Laboratory examinations were performed before, and after 3, 6, and more than 12 months of medication. Acceptance of PC was poor, mainly because of the salty taste of the tablet preparation chosen, and a number of participants dropped out of the study. In the remaining participants, compliance was acceptable when evaluated on the basis of urinary potassium and undesired side effects did not occur. In the short term (up to 3 months), PC evoked compensated metabolic alkalosis (pH and citrate in urine increased; blood gases remained normal), a drop in urinary calcium, together with increasing oxaluria, hydroxyapatite supersaturation, and calcium phosphate crystalluria. In the long term (>12 months) PC urinary pH and citrate dissociated, in that pH returned to pretreatment baseline values, whereas citrate stayed at high levels. In normocitraturics but not in hypocitraturics, urinary urea and sodium in creased with PC. Hypocitraturics appeared to be less sensitive to the effects of PC, as reflected by the relatively small rise in urinary pH and citrate, and they maintained higher mean levels of indicators of bone metabolism (osteocalcin, alkaline phosphatase, hydroxyproline) despite continuous administration of PC. It was concluded that although the PC tablet preparation was effective it may not be an ideal anti-stone drug treatment in the long term and that, especially in hypocitraturiecs, the intrinsic metabolic defect of RCU may not be sufficiently well controlled.  相似文献   
28.
目的:改进透析液中氯化钾含量测定方法提高回收率。方法:将原方法中四苯硼钠的浓度增加到0.02mol/l。结果:测得的回收率从原来的94.79%增加以100.15%。结论:改进后的方法准确、可靠。  相似文献   
29.
AIM: The characteristics of transepithelial transport and uptake of CPU-86017 {[7-(4-chlorbenzyl)-7,8,13,13α-tetrahydroberberine chloride, CTHB]}, a new antiarrhythmia agent and a new derivative of berberine, were investigated on epithelial cell line (Caco-2) to further understand the absorption mechanism of berberine and its derivatives. METHODS: Caco-2 cell was used. RESULTS: 1) The permeability coefficient from the apical (AP) to basolateral (BL) of CPU-86017 was approximately 5 times higher than that from BL-to-AP transport. The effects of a P-glycoprotein (P-gp) inhibitor-cyclosporin A, some surfactants, and lower pH on the transepithelial transport of CPU-86017 were also observed. Cyclosporine A at 7.5 mg/L had no effect on the transepithelial electrical resistance (TEER); an about 4-fold enhancement on the transepithlial transport of CPU-86017 was observed. Some surfactants (sodium citrate, sodium deoxycholate, and sodium dodecyl sulfate) at 100 μmol/L and low pH (pH=6.0) induced a reversible d  相似文献   
30.
小剂量补佳乐在诱导排卵中对子宫内膜发育的影响   总被引:1,自引:0,他引:1  
目的探讨小剂量补佳乐是否能改善克罗米芬诱导排卵中的子宫内膜发育。方法45例不明原因或男方因素的不育妇女分为三组,自然周期组、克罗米芬组(CC组)、克罗米芬 补佳乐组(CC PGV组)各15例,观察三组hCG日及hCG 9d激素环境、子宫内膜厚度、子宫动脉搏动指数(PI),hCG日子宫内膜类型。结果CC组无论hCG日还是hCG 9d内膜厚度均明显小于自然周期组,而CC PGV组内膜厚度均明显大于CC组。CC组和CC PGV组子宫动脉PI无显著差别,但均显著大于自然周期组。结论小剂量补佳乐能改善克罗米芬诱导排卵中子宫内膜的发育。  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