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   8445篇
  免费   447篇
  国内免费   57篇
耳鼻咽喉   114篇
儿科学   182篇
妇产科学   36篇
基础医学   1238篇
口腔科学   171篇
临床医学   489篇
内科学   2303篇
皮肤病学   231篇
神经病学   538篇
特种医学   242篇
外科学   1352篇
综合类   29篇
一般理论   1篇
预防医学   189篇
眼科学   143篇
药学   537篇
中国医学   7篇
肿瘤学   1147篇
  2023年   54篇
  2022年   85篇
  2021年   193篇
  2020年   109篇
  2019年   128篇
  2018年   180篇
  2017年   140篇
  2016年   164篇
  2015年   189篇
  2014年   254篇
  2013年   268篇
  2012年   465篇
  2011年   493篇
  2010年   316篇
  2009年   252篇
  2008年   547篇
  2007年   525篇
  2006年   529篇
  2005年   571篇
  2004年   551篇
  2003年   544篇
  2002年   546篇
  2001年   150篇
  2000年   145篇
  1999年   137篇
  1998年   107篇
  1997年   112篇
  1996年   106篇
  1995年   98篇
  1994年   63篇
  1993年   71篇
  1992年   78篇
  1991年   90篇
  1990年   90篇
  1989年   81篇
  1988年   53篇
  1987年   62篇
  1986年   49篇
  1985年   51篇
  1984年   41篇
  1983年   32篇
  1982年   22篇
  1981年   20篇
  1980年   14篇
  1979年   15篇
  1978年   20篇
  1977年   18篇
  1974年   19篇
  1972年   13篇
  1967年   13篇
排序方式: 共有8949条查询结果,搜索用时 15 毫秒
1.
2.
We report a case of a diaphragmatic hernia after a heart transplant operation. A 43-year-old woman, who underwent orthotropic heart transplantation for hypertrophic cadiomyopathy two year earlier, presented with vomiting and epigastric pain. A computed tomography scan showed that the stomach and transverse colon were dislocated in the left thoracic cavity. We diagnosed left diaphragmatic hernia incarceration and performed laparoscopic repair of the diaphragmatic hernia. A 12 × 8 cm diaphragmatic defect was found intraoperatively on the ventrolateral aspect of the left diaphragm, and the stomach with volvulus had herniated into the thorax through the defect. The hernia was considered to be iatrogenic. The diaphragmatic defect was large, and the diaphragm was thinning. We closed the defect by mesh repair. Laparoscopic mesh repair of the diaphragmatic hernia could be performed safely and with minimal invasiveness.  相似文献   
3.
Although many single nucleotide polymorphism (SNP) studies have reported an association of atopy, allergic diseases and total serum immunoglobulin E (IgE) levels, almost all of these studies sought risk factors for the onset of these allergic diseases. Furthermore, many studies have analyzed a single gene and hardly any have analyzed environmental factors. In these analyses, the results could be masked and the effects of other genes and environmental factors may be decreased. Here, we described the correlation between four genes [interleukin (IL)-4 (C-590T), IL-4 receptor (A1652G), FCER1B (G6842A) and STAT6 (G2964A)] in connection with IgE production; the role of IL-10 (C-627A) as a regulatory cytokine of allergy; and the severity of food allergy (FA) and atopic eczema (AE) in 220 Japanese allergic children. In addition to these SNPs, environmental factors, i.e., patient's attitude, indoor environment, and so on, were also investigated in this study. Our study was retrospective, and the correlation was analyzed by our defined clinical scores divided into three terms: worst symptoms, recent symptoms and general amelioration at the most recent examination during the disease course. Our results indicated that IL-10 AA, the genotype with lower IL-10 production, is associated with higher IgE levels in the serum (p < 0.0001, estimate; 0.912). Marginal liver abnormalities were observed in the subject group with both FA and AE (p < 0.1191, estimate; 0.1490). Our defined clinical scores enabled evaluation of various aspects of disease severity. Based on the scores, while no single SNP selected in this study determined severity, the combination of the SNP with laboratory data and environmental factors appeared to determine severity.  相似文献   
4.
BACKGROUND: The therapies for refractory ulcers on the oral mucosa are symptomatic and very unsatisfactory. We hypothesized that application of growth factors might be able to achieve successful remission of the lesion. We evaluated the effects of systemic administration and topical application of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) on impaired wound healing of ulcers in the rabbit gingiva. METHODS: Almost uniform round ulcers could be created on the gingiva of the rabbits by chemical injury with acetic acid. When the submandibular glands were removed or i.v. injection of cisplatin (CDDP) and peplomycin sulfate was performed before ulcer formation, healing of the ulcers took longer than in untreated rabbits. To ascertain whether or not human EGF and bFGF affect rabbit cells, we first examined the effects of EGF and bFGF on the proliferation of the cells derived from rabbit gingiva. We then applied EGF or bFGF in these impaired healing models. RESULTS: EGF and bFGF promoted proliferation of the fibroblasts, and EGF also promoted proliferation of the keratinocytes isolated from gingival tissue of rabbits in vitro. Systemic injections of EGF and bFGF in rabbits, which had their submandibular glands removed, and topical application of bFGF accelerated healing of ulcers created in rabbits injected with CDDP and peplomycin sulfate. The ability of bFGF to promote the healing of ulcers was much greater than that of EGF. CONCLUSION: Basic FGF may be effective for refractory oral mucosal lesions.  相似文献   
5.
6.
OBJECTIVE: A joint study was undertaken by the Japanese Society of Renal Cancer to investigate the present status of partial nephrectomy in Japan and to speculate about what may be the indications for partial nephrectomy in patients with renal cell carcinoma. METHODS: Data were tabulated for 469 patients from participating medical institutions and various clinical factors were investigated with regard to disease progression (local recurrence and distant metastasis). RESULTS: Disease progression was observed in 21 patients (4.5%). No significant relation to disease progression was observed for sex, laterality, tumor histology, grade and tumor size. Although patients with solitary tumors displayed excellent prognosis irrespective of tumor diameter, patients with multiple tumors displayed a high likelihood of disease progression. Patients older than 77 years old and patients with imperative indication were found to have a poorer prognosis. CONCLUSION: In patients with solitary tumors, partial nephrectomy can be actively performed, even if the patient displays elective indications and the tumor is >4 cm in diameter. In patients displaying multiple tumors with imperative indications, the decision whether to perform partial nephrectomy should be made by the patients and their physicians after considering the impact on curability and the quality of life.  相似文献   
7.
Since humans are under ceaseless orthostatic stress, the mechanism to maintain arterial pressure (AP) under orthostatic stress against gravitational fluid shift is of great importance. We hypothesized that (1) orthostatic stress resets the arterial baroreflex control of sympathetic nerve activity (SNA) to a higher SNA, and (2) resetting of the arterial baroreflex contributes to preventing postural hypotension. Renal SNA and AP were recorded in eight anaesthetized, vagotomized and aortic-denervated rabbits. Isolated intracarotid sinus pressure (CSP) was increased stepwise from 40 to 160 mmHg with increments of 20 mmHg (60 s for each CSP level) while the animal was placed supine and at 60 deg upright tilt. Upright tilt shifted the CSP–SNA relationship (the baroreflex neural arc) to a higher SNA, shifted the SNA–AP relationship (the baroreflex peripheral arc) to a lower AP, and consequently moved the operating point to marked high SNA while maintaining AP. A simulation study suggests that resetting in the neural arc would double the orthostatic activation of SNA and increase the operating AP in upright tilt by 10 mmHg, compared with the absence of resetting. In addition, upright tilt did not change the CSP–AP relationship (the baroreflex total arc). A simulation study suggests that although a downward shift of the peripheral arc could shift the total arc downward, resetting in the neural arc would compensate this fall and prevent the total arc from shifting downward to a lower AP. In conclusion, upright tilt increases SNA by resetting the baroreflex neural arc. This resetting may compensate for the reduced pressor responses to SNA in the peripheral cardiovascular system and contribute to preventing postural hypotension.  相似文献   
8.
1. Endothelium-dependent relaxation in response to acetylcholine (ACh) and the calcium ionophore A 23187 was examined in aorta, coronary, basilar and renal arteries isolated from Watanabe heritable hyperlipidaemic (WHHL) rabbits of 2, 6 and 12 months of age, with normolipidaemic heterozygous WHHL rabbits as controls. 2. In the rings of WHHL rabbit aortae and coronary arteries preconstricted with vasoconstrictors, endothelium-dependent relaxation in response to ACh was attenuated with age compared to the heterozygous WHHL rabbits. A significant negative correlation was found between the total cholesterol content and the relaxation response to ACh in the aortae or coronary arteries from 6 and 12 month old WHHL rabbits. 3. In the rings of basilar arteries, endothelium-dependent relaxations to ACh were not modified with age. Similarly, in the rings of renal arteries, the relaxation response to ACh was not changed with age, but in the 6 and 12 month preparations, after the age of 6 months, a contraction following the relaxation appeared at higher concentrations of ACh (10?7 to 10?6 mol/L). The contraction was endothelium-dependent and inhibited by indomethacin. 4. A 23187-induced endothelium-dependent relaxations were also markedly attenuated in the aorta and significantly in the coronary artery with age. 5. Endothelium-independent relaxation to sodium nitroprusside was not changed in all arteries from WHHL rabbits of different ages. 6. These findings indicate that in the aorta and coronary artery of the WHHL rabbit, the endothelium-dependent relaxation to ACh and A 23187 becomes impaired with increasing age (i.e., with the progression of cholesterol deposition in the arterial wall) but is preserved in the basilar and renal artery.  相似文献   
9.
Summary Total body bone mineral (TBBM) content in rats was measured by dual photon absorptiometry (DPA). TBBM showed significant increases over 4 weeks in control groups with significant bone loss over the same time in prednisolone-injected rats on low calcium feed. Daily injections of calcitonin significantly reduced loss of bone mass. Both prednisolone- and prednisolone-calcitonin-injected groups showed significantly elevated serum alkaline phosphatase with the prednisolone-calcitonin group also exhibiting elevated serum calcium and phosphate levels, confirming the impact of the experimental protocol. TBBM measured by DPA in all groups correlated well (r=0.928,P<0.001 n=20) with the total ash weight suggesting that the method reflects total skeletal mineral content in the small animal. TBBM measurement by DPA proves well-suited to monitoring bone mineral in a small animal experimental setting.  相似文献   
10.
Eight patients underwent pouchmetry at 12 months after creation of the colonic continent urinary reservoir (CUR) for supravesical diversion. Pouchmetry revealed a volume-dependent tonic and phasic increase in pouch pressure in 3 patients who had undergone pouch construction using the partially detubularized right colon (Heineke-Mikulicz type closure after splitting the transverse and ascending colon at the antimesenteric border), whereas the volume-dependent phasic increase in pouch pressure was much less remarkable in 5 patients whose pouch was constructed using the totally detubularized right colon (Heineke-Mikulicz type closure after splitting the whole colonic segment including the cecum). The maximum pouch pressure at the pouch volume of 400 to 500 ml was significantly higher (p less than 0.05) in the partial detubularization group (46 +/- 6.0 cmH2O, mean +/- S.D.) than in the total detubularization group (12 +/- 1.6 cmH2O). In creation of the low-pressure pouch using the right colon, detubularization should extend to the whole portion of the isolated colonic segment.  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