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   1952篇
  免费   104篇
  国内免费   50篇
耳鼻咽喉   9篇
儿科学   40篇
妇产科学   70篇
基础医学   241篇
口腔科学   49篇
临床医学   204篇
内科学   340篇
皮肤病学   9篇
神经病学   160篇
特种医学   203篇
外科学   163篇
综合类   69篇
预防医学   129篇
眼科学   53篇
药学   238篇
中国医学   23篇
肿瘤学   106篇
  2023年   5篇
  2022年   19篇
  2021年   33篇
  2020年   20篇
  2019年   28篇
  2018年   50篇
  2017年   18篇
  2016年   35篇
  2015年   48篇
  2014年   60篇
  2013年   82篇
  2012年   88篇
  2011年   135篇
  2010年   75篇
  2009年   65篇
  2008年   110篇
  2007年   122篇
  2006年   93篇
  2005年   107篇
  2004年   87篇
  2003年   79篇
  2002年   61篇
  2001年   63篇
  2000年   41篇
  1999年   23篇
  1998年   49篇
  1997年   62篇
  1996年   37篇
  1995年   35篇
  1994年   29篇
  1993年   23篇
  1992年   21篇
  1991年   20篇
  1990年   18篇
  1989年   27篇
  1988年   35篇
  1987年   26篇
  1986年   34篇
  1985年   30篇
  1984年   16篇
  1983年   13篇
  1982年   18篇
  1981年   8篇
  1980年   15篇
  1979年   6篇
  1978年   7篇
  1977年   9篇
  1976年   14篇
  1975年   4篇
  1973年   3篇
排序方式: 共有2106条查询结果,搜索用时 500 毫秒
11.
The study has explored 11 correlative variables which might affect the gallblad-der pressure GBP of patients with gall stone after auricular electrical stimulation by means of multiplestepwise regression. It was found that the size of gallbladder stone (X9), cholecystolithiasis (X4),sex (X1), and the baseline of GBP (X10) could affect the GBP change range (Y1) depressingly orreinforcingly. Also the baseline of GBP (Y1) could be affected by the variables X1 (sex), X2 (age),and X6 (long diameter of the gallbladder, LDGB), etc.. The result shows that the change in GBPafter auricular electrical stimulation is comprehensively influenced by multiple factors. And it providessome useful information for predicting the curative effect of auricular therapy on gallbladder stone inclinic.  相似文献   
12.
13.
Summary— In the present study we have compared the steady state biopharmaceutic characteristics of four diltiazem once daily controlled release capsules: Mono-Tildiem LP 300® (300 mg), Adizem® XL (300 mg)1, Cardizem® (300 mg) and Dilacor® (240 mg). Sixteen healthy male volunteers (aged 22.9 ± 3.3 years, range 19–31 years) completed an open label, multiple oral dose, randomized, four-period crossover study without a washout period in between. The volunteers received each diltiazem formulation once daily for four days. Trough diltiazem and metabolites plasma concentrations were determined on days 3 and 4. The 24-h plasma concentration-time profiles were assessed after the dose on day 4 of each period. The following steady state pharmacokinetic parameters for diltiazem were calculated: the minimum plasma concentration (cmin), the maximum plasma concentration (cmax), the time to reach that concentration (tmax), the time interval during which the plasma concentration exceeds 50% of cmax (t50), the area under the plasma concentration-time curve (AUC72–96) and the peak-to-trough fluctuation (PTF). For the metabolites of diltiazem, N-mono-desmethyl-diltiazem (NDM) and desacetyldiltiazem (DAD), AUC72–96 (AUCNDM and AUCDAD) and the ratio metabolite/parent compound were calculated. Steady state was achieved on day 3. Except one, all controlled release formulations have satisfactory controlled release properties allowing once daily administration. However, significant (P < 0.05) differences were found between the pharmacokinetic characteristics which do not allow exchange of the various formulations. Concentrations well below 50 ng·mL-1 in the morning hours were observed for Dilacor® (240 mg) and Adizem® XL (300 mg), which could be a disadvantage of these formulations as it is well-known that ischaemic events occur at a higher rate during that part of the day. The plasma concentration profiles of NDM and DAD, the major circulating metabolites, parallel the plasma concentration profiles for the parent compound. From a clinical point of view, all treatments were well tolerated.  相似文献   
14.
Sympathetic skin response (SSR) and R–R interval variation (RRIV) were studied in 36 chronic, nondiabetic uremics to compare with their nerve conduction studies (NCS) and clinical dysautonomia. Abnormal SSR was noted in 5 (13.9%) patients, abnormal RRIV in 14 (38.9%), and abnormal NCS in 26 (72.2%). The patients were classified into three groups: group (GP) 1: “normal,” n = 21 (58.3%), normal RRIV and SSR; GP 2: “isolated parasympathetic dysfunction,” n = 10 (27.8%), abnormal RRIV and normal SSR; and GP 3: “sympathetic sudomotor dysfunction,” n = 5 (13.9%), abnormal SSR. A significant difference in age was found among the three groups (GP 3 > GP 2 > GP 1; P < 0.0001, ANOVA). After controlling the age factor, we still noted a tendency toward increasing NCS disturbances (distal latency and nerve conduction velocity of peroneal nerve; P < 0.05, multiple regression analysis) and frequencies of clinical autonomic symptoms (postural dizziness and impotence; P < 0.05, Mantel–Hanszel test) from GP 1 to GP 3. Patients with abnormal SSR (GP 3) displayed significantly higher frequencies of postural dizziness and impotence, indicating the relationship between an absence of SSR and clinical dysautonomia. © 1994 John Wiley & Sons, Inc.  相似文献   
15.
Intestinal obstruction proximal to a transition zone without an interposed physical barrier usually indicates Hirschsprung disease. The authors report one case of focal small bowel muscular thinning just distal to a transition zone that produced clinical and radiographic findings that simulated long-segment Hirschsprung disease in a 2-day-old infant.  相似文献   
16.
An outbreak of influenza virus type B infection occurred in Philadelphia from December, 1985, to April, 1986. During this epidemic 24 patients were admitted to Children's Hospital from whom influenza B was isolated from routine respiratory viral cultures. All were younger than 3 years of age. Clinical findings included fever (greater than or equal to 38 degrees C) (88%), rhinorrhea (62.6%), cough (50%), otitis (50%), rhonchi (42%), vomiting (38%), diarrhea (33%), rales (21%), pharyngitis (13%) and croup (4%). Remarkably 75% of the patients had underlying diseases which may have contributed to the severity of the infection. Nine (41%) patients had pneumonia. Two patients died of respiratory failure caused by overwhelming influenza B virus infection. Patients admitted to the hospital with respiratory and underlying diseases should have viral respiratory cultures which include influenza B.  相似文献   
17.
After a severe episode of ischemia, traumatic brain injury (TBI) or epilepsy, it is typical to find necrotic cell death within the injury core. In addition, a substantial number of neurons in regions surrounding the injury core have been observed to die via the programmed cell death (PCD) pathways due to secondary effects derived from the various types of insults. Apart from the cell loss in the injury core, cell death in regions surrounding the injury core may also contribute to significant losses in neurological functions. In fact, it is the injured neurons in these regions around the injury core that treatments are targeting to preserve. In this review, we present our cumulated understanding of stress-activated signaling pathways and apoptotic pathways in the research areas of ischemic injury, TBI and epilepsy and that gathered from concerted research efforts in oncology and other diseases. However, it is obvious that our understanding of these pathways in the context of acute brain injury is at its infancy stage and merits further investigation. Hopefully, this added research effort will provide a more detailed knowledge from which better therapeutic strategies can be developed to treat these acute brain injuries.  相似文献   
18.
Recently, in-vitro maturation (IVM) of immature human oocytes recovered from non-stimulated follicles has been applied in the treatment of infertility. However, in previous reports, very few embryos cultured in conventional medium have reached the expanded blastocyst stage following in-vitro maturation and fertilization (IVM/IVF). The objective of this study was to investigate whether the developmental competence of human embryos following IVM/IVF could be enhanced by the use of a human ampullary cell co-culture system. Immature human oocytes were aspirated from small follicles at Caesarean section and then cultured in medium containing human menopausal gonadotrophin for 36 to 48 h, followed by insemination. Zygotes were randomly cultured either in conventional culture medium alone or in the co-culture system. Of 48 embryos cultured in conventional medium alone, all arrested at the 2-16- cell stage on day 3 after insemination. Of 46 embryos cultured in the co-culture system, 26 embryos (56.5%) arrested at the 2-16-cell stage. Six embryos (13%) developed to the morula stage. Fourteen embryos (30.4%) developed to expanded blastocysts and two blastocysts were hatching on day 7 after insemination. We conclude that co-culture significantly enhances the development of blastocysts in embryos resulting from IVM/IVF.   相似文献   
19.
The differentiation of the urinogenital system and the appendicular skeleton in vertebrates is under the control of Hox genes. The common control of digit and gonad differentiation raises the possibility that patterns of digit formation may relate to spermatogenesis and hormonal concentrations. This work was concerned with the ratio between the length of the 2nd and 4th digit (2D:4D) in humans. We showed that (i) 2D:4D in right and left hands has a sexually dimorphic pattern; in males mean 2D:4D = 0.98, i.e. the 4th digit tended to be longer than the 2nd and in females mean 2D:4D = 1.00, i.e. the 2nd and 4th digits tended to be of equal length. The dimorphism is present from at least age 2 years and 2D:4D is probably established in utero; (ii) high 2D:4D ratio in right hands was associated with germ cell failure in men (P = 0.04); (iii) sperm number was negatively related to 2D:4D in the right hand (P = 0.004); (iv) in men testosterone concentrations were negatively related to right hand 2D:4D and in women and men LH (right hand), oestrogen (right and left hands) and prolactin (right hand) concentrations were positively correlated with 2D:4D ratio and (v) 2D:4D ratio in right hands remained positively related to luteinizing hormone and oestrogen after controlling for sex, age, height and weight.   相似文献   
20.
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