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   6869篇
  免费   220篇
  国内免费   38篇
耳鼻咽喉   240篇
儿科学   136篇
妇产科学   295篇
基础医学   835篇
口腔科学   49篇
临床医学   444篇
内科学   1871篇
皮肤病学   129篇
神经病学   606篇
特种医学   113篇
外科学   739篇
综合类   59篇
一般理论   10篇
预防医学   328篇
眼科学   199篇
药学   676篇
中国医学   4篇
肿瘤学   394篇
  2023年   27篇
  2022年   176篇
  2021年   261篇
  2020年   73篇
  2019年   138篇
  2018年   154篇
  2017年   113篇
  2016年   127篇
  2015年   166篇
  2014年   212篇
  2013年   321篇
  2012年   447篇
  2011年   567篇
  2010年   279篇
  2009年   185篇
  2008年   448篇
  2007年   540篇
  2006年   498篇
  2005年   534篇
  2004年   524篇
  2003年   453篇
  2002年   395篇
  2001年   22篇
  2000年   24篇
  1999年   28篇
  1998年   30篇
  1997年   18篇
  1996年   24篇
  1995年   33篇
  1994年   21篇
  1993年   18篇
  1992年   16篇
  1991年   22篇
  1990年   9篇
  1989年   12篇
  1988年   8篇
  1987年   16篇
  1986年   9篇
  1985年   14篇
  1984年   22篇
  1983年   16篇
  1982年   22篇
  1981年   12篇
  1980年   10篇
  1979年   15篇
  1978年   12篇
  1977年   7篇
  1976年   5篇
  1974年   7篇
  1973年   6篇
排序方式: 共有7127条查询结果,搜索用时 15 毫秒
51.
OBJECTIVES: Considering the enormous advantages of minimally invasive surgery, attempts to introduce less invasive trans-abdominal incisions might represent an alternative to classic gynecologic surgery. The aim of this study is to assess the feasibility and clinical outcome of minilaparotomy in patients operated due to benign gynecological diseases and to analyze selected parameters with regard to the abdominal wall incision size. DESIGN: In this retrospective study, we have described our experience with 26 patients, undergoing minilaparotomy for benign adnexal or uterine diseases. MATERIAL AND METHODS: 26 patients with benign uterine or adnexal diseases, hospitalized from November 2003 until March 2006 at the Department of Surgical and Endoscopic Gynecology at the Polish Mother's Memorial Hospital--Research Institute in Lód?, had undergone successful surgical treatment by means of minilaparotomy. The following procedures were included in the analysis: myomectomy (17 patients), ovarian cystectomy (3 patients), myomectomy and ovarian cystectomy at the same time (3 patients), bilateral salpingo-oophorectomy (1 patient), supracervical hysterectomy (1 patient) and total abdominal hysterectomy with salpingo--oophorectomy (1 patient). RESULTS: The patients' mean age and BMI were 33.85 years (14-50) and 22.95 (18.73-45.17), respectively. The mean operative time was 72.69 min (45-120). The diameter of trans-abdominal incision was 3-6cm and the mean diameter of removed lesions was 76.88 mm (47-200). The mean intraoperative decrease of haematocrit and haemoglobin value was 4.8% (0.2-12.4) and 1.4 g/dl (0.2-3.7), respectively. Blood transfusion was required in case of 3 patients but only in one case it was caused by intraoperative blood loss. There were no significant intra- or postoperative complications. 16 patients needed analgesics for 2.33 days after surgery. Body temperature up to 38 degrees C was observed in 4 patients for 2.5 days. The average time of hospitalization after the surgery was 4.58 days. We have noted a negative correlation between the size of trans-abdominal incision and several factors: operative time, intraoperative blood loss, period of analgesic therapy and time of hospitalization after the surgery. None of these factors was correlated with patients' age or BMI. One-month follow up after the surgery revealed satisfactory wound healing and no complains in case of all patients. All patients deemed the cosmetic effect of the surgery very good. CONCLUSION: Minilaparotomy seems to be a very simple, useful and safe surgical technique which might be an alternative to laparotomy in the management of benign gynecologic diseases. Minilaparotomy is of great value, especially in situations when laparoscopic or vaginal approach is too complicated or too dangerous due to technical reasons.  相似文献   
52.
Rho kinase plays a key role in the regulation of smooth muscles contraction, including those of the urinary bladder detrusor. Rho kinase pathway modulates the level of phosphorylation of the myosin light chain, mainly through the inhibition of myosin phosphatase. Recent experimental data indicate that its role might be exacerbated in local and systemic pathological conditions which affect the bladder. It seems that Rho kinase inhibitors, such as Y27632, may turn out to be an effective group of drugs in pharmacotheraphy of an overactive bladder (OAB), which will influence the storage phase of the micturition cycle, without interfering with the physiological voiding.  相似文献   
53.
OBJECTIVES: The aim of the study was to evaluate the value of intraoperative assessment of depth of myometrial invasion in patients with FIGO stage I of the endometrial carcinoma. MATERIAL AND METHODS: A total number of 112 patients with FIGO stage I of the endometrial carcinoma undergoing surgery were enrolled in the study. All patients had undergone intraoperative assessment of the depth of myometrial invasion performed by a surgeon. The depth was determined as more or less than 50% of myometrial thickness according to FIGO classification. Gross visual estimation of the depth of myometrial invasion at the time of the operation was compared with the final histopathological report. Sensitivity, specificity and positive and negative predictive values of the method were determined by means of statistical analyses. RESULTS: The depth of the myometrial invasion was accurately determined by the surgeon in 82.1% of cases. Sensitivity and specificity were 68% and 82.1%, respectively. The accurate prediction rate of the myometrial invasion in the group of patients with well differentiated (G1) endometrial carcinoma was higher (88.4%) than in group with moderately and low differentiated tumour (78.3%). CONCLUSIONS: The accuracy of macroscopic evaluation of myometrial invasion is high and reaches up to 82.1%. The accurate determination rate increases if the differentiation of tumour is higher.  相似文献   
54.
55.
56.
Monocyte activity after stimulation by serum of women with endometriosis   总被引:1,自引:0,他引:1  
OBJECTIVES: Impairments of immune system play an important role in the development and pathogenesis of endometriosis. In affected women peritoneal macrophages are excessively activated, which is visible in an increased synthesis and release of macrophage-derived cytokines and growth factors. Monocytes are precursors of those cells in peripheral blood. The aim of the study was to evaluate the activity of monocyte from a healthy person, after stimulation by serum of women with endometriosis in cell culture conditions. The indicator of monocyte activity was the concentration of neopterin (NPT), produced by those cells. MATERIAL AND METHODS: Twenty nine women with endometriosis (mean age: 28.7+/-4.5 years) were included into this study. Among them were 18 women with moderate endometriosis (I and II stages according to AFS) and 11 women with advanced stages of the disease (III and IV stages according to AFS). Reference group consisted of fifteen healthy women (mean age: 27.4+/-5.3 years), with excluded endometriosis and other pathological disorders within the pelvis. Monocytes used in the study were isolated from peripheral blood of a healthy male and serum of women with endometriosis and control group. Monocytes were cultured in attendance of 15% and 30% serum of studied women. The concentration of NPT in the supernatants of culture was measured by enzyme-linked immunosorbent ELISA assay. RESULTS: The serum of women with endometriosis causes an increased concentration of NPT in supernatants, when comparing with serum of healthy women (p<0. 0001). The highest concentration was observed after stimulation by serum of women with advanced endometriosis. CONCLUSIONS: Serum of women with endometriosis can have an effect on monocyte activity, which is displayed in the increased synthesis and secreted of NPT.  相似文献   
57.
58.
Recovery of zinc and manganese from scrapped alkaline batteries were carried out in the following way: leaching in H2SO4 and selective precipitation of zinc and manganese by alkalization/neutralization. As a result of non-selective leaching, 95.6–99.7% Zn was leached and 83.7–99.3% Mn was leached. A critical technological parameter is the liquid/solid treatment (l/s) ratio, which should be at least 20 mL∙g−1. Selective leaching, which allows the leaching of zinc only, takes place with a leaching yield of 84.8–98.5% Zn, with minimal manganese co-leaching, 0.7–12.3%. The optimal H2SO4 concentration is 0.25 mol∙L−1. Precipitation of zinc and manganese from the solution after non-selective leaching, with the use of NaOH at pH = 13, and then with H2SO4 to pH = 9, turned out to be ineffective: the manganese concentrate contained 19.9 wt.% Zn and zinc concentrate, and 21.46 wt.% Mn. Better selectivity results were obtained if zinc was precipitated from the solution after selective leaching: at pH = 6.5, 90% of Zn precipitated, and only 2% manganese. Moreover, the obtained concentrate contained over 90% of ZnO. The precipitation of zinc with sodium phosphate and sodium carbonate is non-selective, despite its relatively high efficiency: up to 93.70% of Zn and 4.48–93.18% of Mn and up to 95.22% of Zn and 19.55–99.71% Mn, respectively for Na3PO4 and Na2CO3. Recovered zinc and manganese compounds could have commercial values with suitable refining processes.  相似文献   
59.
Tetrahedrites, due to their promising thermoelectric properties, are one of the materials being investigated for use in thermoelectric generators. One problem is the lack of n-type tetrahedrites, which would be beneficial for the design of tetrahedrite thermoelectric modules. Preliminary theoretical studies have shown that elements from groups I and II can be introduced into the structural voids of tetrahedrite, acting as donor dopants, and should enable n-type conductivity. Therefore, in this work, an attempt was made to obtain and study magnesium-doped tetrahedrites. A series of samples, MgxCu12Sb4S13, with different magnesium contents were obtained and their phase and chemical compositions were characterized. It was observed that the structural changes occurring upon doping indicate that Mg atoms are likely to be embedded in the structural voids. The experimental studies have been supported by electronic structure calculations indicating that the most likely location of Mg is in the structural voids at the 6b Wyckoff position. Seebeck coefficient and resistivity measurements showed that doping with Mg reduces the concentration of holes, which is consistent with the predicted donor character of the dopant. However, the introduction of magnesium in sufficient amounts to achieve n-type conductivity was not successful.  相似文献   
60.
The article presents research on the potential use of organometallic compounds with the addition of antimony (III) oxide Sb2O3 as a coating additive that will make coatings susceptible to electroless metallization after prior surface irradiation with 193 nm wavelength laser radiation and a different number of laser pulses. The surface modification and activation effects were assessed by optical-imagining as well as by scanning electron microscopy (SEM) with energy dispersive analysis (EDX). It was found that the presence of Sb2O3 in the coating made it possible to reduce the content of the copper complex, causing an intensive surface ablation, resulting in the formation of a conical structure with a higher content of metallic copper nuclei.  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