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   2410篇
  免费   186篇
  国内免费   8篇
耳鼻咽喉   88篇
儿科学   138篇
妇产科学   150篇
基础医学   200篇
口腔科学   145篇
临床医学   224篇
内科学   428篇
皮肤病学   75篇
神经病学   133篇
特种医学   72篇
外科学   553篇
综合类   19篇
预防医学   88篇
眼科学   70篇
药学   148篇
中国医学   5篇
肿瘤学   68篇
  2024年   5篇
  2023年   52篇
  2022年   38篇
  2021年   84篇
  2020年   49篇
  2019年   86篇
  2018年   168篇
  2017年   100篇
  2016年   147篇
  2015年   131篇
  2014年   186篇
  2013年   263篇
  2012年   187篇
  2011年   149篇
  2010年   139篇
  2009年   75篇
  2008年   84篇
  2007年   90篇
  2006年   86篇
  2005年   96篇
  2004年   57篇
  2003年   55篇
  2002年   45篇
  2001年   35篇
  2000年   24篇
  1999年   28篇
  1998年   32篇
  1997年   27篇
  1996年   20篇
  1995年   14篇
  1994年   13篇
  1993年   4篇
  1992年   8篇
  1991年   4篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1986年   2篇
  1985年   2篇
  1983年   1篇
  1982年   1篇
  1980年   2篇
  1979年   1篇
  1978年   2篇
  1977年   2篇
  1974年   1篇
  1972年   1篇
  1965年   1篇
  1962年   1篇
  1934年   1篇
排序方式: 共有2604条查询结果,搜索用时 15 毫秒
1.
BACKGROUND: Superficial lymphatic malformations are predominantly developmental malformations of infancy, but they may arise at any age. OBJECTIVE: To describe a patient with a late-onset superficial lymphatic malformation. METHODS: Case report and literature review. RESULTS: A 53-year-old woman was evaluated for a colored lesion that developed spontaneously on the anterior abdominal wall. The lesion was treated by surgical excision. Findings on histopathologic examination of the specimen were consistent with superficial lymphatic malformation. There was no recurrence of the lesion at 4 months after the operation. CONCLUSION: Superficial lymphatic malformations can develop in adults spontaneously without the presence of any predisposing condition. Because the majority of such late-onset malformations reported in the literature are localized lesions similar to the one in our patient, surgical removal with inclusion of subcutaneous tissue usually results in cure without recurrence.  相似文献   
2.
Intravenous Pyogenic Granuloma of the Hand   总被引:1,自引:0,他引:1  
BACKGROUND: Intravenous pyogenic granuloma is the intravasal counterpart of cutaneous pyogenic granuloma. This rare, benign lesion appears clinically as a subcutaneous nodule usually located in the upper extremity or neck in middle-aged people. It is hard to make an exact diagnosis on clinical basis, and there is a risk of recurrence because of undertreatment. OBJECTIVE: To report a case of an intravenous pyogenic granuloma located in the hand and to describe the clinical and histopathologic features of this rare vascular tumor. METHODS: An operation was performed on a 58-year-old female who presented with a small, painless mass in the right palm, and the pathologic examination revealed an intravenous pyogenic granuloma. CONCLUSION: This rare lesion should be differentiated from a regular pyogenic granuloma and should be excised with the vein segment to avoid recurrence.  相似文献   
3.
The relaxant effects of electrical field stimulation (EFS) and exogenously applied acetylcholine (ACh) or acidified NaNO2 (a-NaNO2) were investigated in the isolated mouse corpus cavernosum precontracted with phenylephrine hydrochloride (PE). Tetrodotoxin (TTX) blocked the relaxant effects of EFS completely, whereas it had no effect on the responses to ACh or a-NaNO2. Guanethidine and indomethacin failed to affect the electrically or ACh-induced relaxations. Atropine completely blocked the effect of ACh; however, it caused a slight reduction in the relaxation evoked by EFS.N G- Nitro-l-arginine (l-NOARG) reduced the effects of EFS and ACh significantly, but it was ineffective on the relaxations induced by a-NaNO2. The inhibitory action ofl-NOARG was partly restored byl-arginine, but not byd-arginine. Methylene blue (MB) and hydroxocobalamin (HC) exhibited significant inhibition on the relaxations evoked by EFS, ACh and a-NaNO2. Hydroquinone (HQ) reduced relaxation due to a-NaNO2, but did not affect that of EFS and ACh. Our findings suggest that EFS-induced relaxations of mouse cavernosal tissue are mediated by a transmitter which probably resembles an organic nitrate.  相似文献   
4.
Radius, ulna, short bones (RUS), carpal (CARP) bone age (BA), tibial corticodiaphyseal (C/D) ratio and trabecular aspect were assessed in 19 children with steroid dependent nephrotic syndrome and 15 age matched healthy children. Both RUS and CARP BA were significantly lower than in the controls. Trabecular aspect and tibial C/D ratio did not show any statistical significance. There was a positive correlation between HSDS and RUS BA delay (r=−0.476, p<0.05); CARP BA delay and RUS BA delay (r=0.563, p<0.01) and RUS BA and CARP BA (r=0.891, p<0.001). In conclusion, RUS and CARP BA are both retarded and positively correlated in steroid dependent nephrotic children.  相似文献   
5.
Extracorporeal septoplasty is a radical solution for the severely deviated nose. The major problems associated with this procedure are fixation of the septal cartilage graft and dorsal irregularities. Extracorporeal septoplasty was performed in combination with open rhinoplasty in 17 patients with severe nasal deformities. In this technique septum was totally removed through the columellar incision of open rhinoplasty, corrected outside, and replaced as a free ``L' shaped cartilage graft. The cartilage graft was fixated to the upper lateral cartilages to restore the natural relations of the anatomical structures. Additional rhinoplastic manipulations were also performed. The follow-up period was up to 18 months. The overall result was successful in all patients. Nasal deviation did not recur and secondary revisions were not needed for any patient during follow-up.  相似文献   
6.
BACKGROUND: We aimed to determine whether serum concentrations of anti-Müllerian hormone (AMH) can be used as a tool for prediction of the efficacy of sperm retrieval. METHODS: This was a prospective cohort observational study. AMH levels were determined in 47 men presenting for infertility evaluation. Group 1 consisted of 24 infertile patients diagnosed with non-obstructive azoospermia. Group 1 was further divided into two subgroups. The patients with spermatozoa in their testicular samples constituted group 1a (n = 13), while the patients with absence of spermatozoa constituted group 1b (n = 11). Twenty-three normozoospermic fertile men constituted group 2. Serum AMH was measured before obtaining testicular specimens. RESULTS: Testicular spermatozoa were recovered in 13 out of the 24 patients (54%). Demographic characteristics of the three groups were similar. The difference between serum AMH levels among the three groups did not reach statistical significance. CONCLUSIONS: We speculated that although AMH is secreted predominantly into the seminiferous tubules, studying serum samples might be more advantageous than seminal plasma because the presence of seminal proteases could influence AMH levels in the latter. However, our results did not demonstrate differences in serum concentrations of AMH between the studied groups. Studies with extended patient populations focusing on seminal plasma concentrations of AMH are warranted.  相似文献   
7.
8.
Vascular smooth muscle cells (VSM) are normally exposed to transmural fluid flow shear stresses, and after vascular injury, blood flow shear stresses are imposed upon them. Since Ca2+ is a ubiquitous intracellular signaling molecule, we examined the effects of fluid flow on intracellular Ca2+ concentration in rat aortic smooth muscle cells to assess VSM responsiveness to shear stress. Cells loaded with fura 2 were exposed to steady flow shear stress levels of 0.5–10.0 dyn/cm2 in a parallel-plate flow chamber. The percentage of cells displaying a rise in cytosolic Ca2+ ion concentration ([Ca2+]i) increased in response to increasing flow, but there was no effect of flow on the ([Ca2+]i) amplitude of responding cells. Addition of Gd3+ (10 M) or thapsigargin (50 nM) significantly reduced the percentage of cells responding and the response amplitude, suggesting that influx of Ca2+ through ion channels and release from intracellular stores contribute to the rise in ([Ca2+]i) in response to flow. The addition of nifedipine (1 or 10 M) or ryanodine (10 M) also significantly reduced the response amplitude, further defining the role of ion channels and intracellular stores in the Ca2+ response. © 2002 Biomedical Engineering Society. PAC2002: 8716Uv, 8719Uv, 8716Dg, 8719Ff  相似文献   
9.
Several problems in the management of life-threatening mucormycosis remain unresolved, necessitating new methods of management. Four patients with histopathologically proven rhinocerebral mucormycosis were treated with high cumulative doses of granulocyte colony-stimulating factor (G-CSF). All had multiple predisposing factors for mucormycosis, particularly leukemia and neutropenia. Two patients refractory to fluconazole therapy were treated with liposomal amphotericin B. The improvement in clinical manifestations was closely related to neutrophil recovery, and all patients were alive at the end of therapy. In addition to surgical debridement and antifungal therapy, G-CSF seems to have played a role in their survival.  相似文献   
10.
BACKGROUND: Patients with allergic rhinitis and bronchial hyperresponsiveness (BHR) may be at higher risk of developing asthma. OBJECTIVE: To investigate whether reactivity to aeroallergens in skin prick testing (SPT) and serum eosinophil cationic protein levels can be used to predict BHR in allergic rhinitis patients. METHODS: Fifty-nine consecutive patients with allergic rhinitis underwent SPTs using grass, tree, weed, parietaria, Alternaria, Aspergillus, mites, and cat and dog dander extracts. Methacholine challenge tests were performed using spirometry. RESULTS: Methacholine-induced BHR was detected in 23 patients (39%). Of 59 patients, 14 had 1 positive SPT response, 35 had 2 to 4 positive responses, and 10 had more than 4 positive responses. There was a significant inverse correlation between methacholine provocation concentration that caused a decrease in forced expiratory volume in 1 second of 20% (PC20) and the number of positive SPT responses (r = -0.28; P = .03). The BHR-positive patients had a mean of 4 positive SPT responses, whereas BHR-negative patients had a mean of 2.6 (P = .04). Nine BHR-positive patients (39%) and only 1 BHR-negative patient (3%) had more than 4 positive SPT responses (P < .001). There was no correlation between serum eosinophil cationic protein levels and methacholine PC20 doses. There was a strong association between hyperresponsiveness to methacholine and both cat and dog dander sensitivity (P < .001 and P = .001, respectively). CONCLUSIONS: Allergic rhinitis patients with SPT responses to a higher number of allergens are more likely to have BHR. Whether the number of positive SPT responses correlates with the risk of developing asthma in allergic rhinitis patients remains to be determined.  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