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   21281篇
  免费   1039篇
  国内免费   102篇
耳鼻咽喉   173篇
儿科学   285篇
妇产科学   360篇
基础医学   2795篇
口腔科学   532篇
临床医学   1353篇
内科学   5337篇
皮肤病学   323篇
神经病学   1765篇
特种医学   840篇
外科学   3570篇
综合类   91篇
一般理论   1篇
预防医学   602篇
眼科学   538篇
药学   1615篇
中国医学   68篇
肿瘤学   2174篇
  2023年   110篇
  2022年   208篇
  2021年   333篇
  2020年   266篇
  2019年   308篇
  2018年   384篇
  2017年   285篇
  2016年   376篇
  2015年   400篇
  2014年   516篇
  2013年   636篇
  2012年   998篇
  2011年   1067篇
  2010年   610篇
  2009年   509篇
  2008年   924篇
  2007年   954篇
  2006年   879篇
  2005年   917篇
  2004年   988篇
  2003年   881篇
  2002年   910篇
  2001年   812篇
  2000年   841篇
  1999年   767篇
  1998年   278篇
  1997年   210篇
  1996年   171篇
  1995年   160篇
  1994年   158篇
  1993年   133篇
  1992年   540篇
  1991年   458篇
  1990年   465篇
  1989年   469篇
  1988年   416篇
  1987年   354篇
  1986年   352篇
  1985年   350篇
  1984年   242篇
  1983年   181篇
  1979年   167篇
  1978年   120篇
  1977年   115篇
  1974年   88篇
  1972年   89篇
  1971年   95篇
  1970年   83篇
  1968年   94篇
  1967年   90篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Small guanosine triphosphatase RhoA has been known to re‐organize cytoskeletons and regulate cell migration. The present authors have previously reported that expression of RhoA is significantly increased in advanced ovarian carcinomas and also in the peritoneal disseminated lesions. The present study investigated whether overexpression of RhoA could alter the progressive behavior of ovarian cancer cells. The effect of various Rho inhibitors on the biological behavior of ovarian cancer cells in vitro and in vivo was also examined. A stable RhoA‐transfectant of an ovarian cancer cell line SKOV3 was generated and examined in vitro for alterations of proliferative activity and invasiveness, and also in the nude mice model for peritoneal dissemination. In addition, the effect of a specific Rho inhibitor (C3 exoenzyme), Rho kinase inhibitor (Y27632) and hydroxymethylglutaryl coenzyme A (HMG–CoA) reductase inhibitor (Lovastatin and Pravastatin) were studied in vitro and in vivo. Forced overexpression of RhoA did not alter proliferative activity but significantly increased the invasiveness in vitro, which was suppressed by addition of C3 exoenzyme, Y27834, Lovastatin and Pravastatin. In the nude mice model, the frequency of dissemination and the number of disseminated lesions were significantly increased in the RhoA transfectant than in the control. In addition, oral administration of Lovastatin significantly decreased the number of metastatic sites compared with the control. These findings suggest that upregulation and/or activation of RhoA play an important role in the peritoneal dissemination of ovarian carcinoma, and that Lovastatin might be a candidate for the possible, novel treatment for ovarian carcinoma patients with peritoneal dissemination. (Cancer Sci 2008; 99: 2532–2539)  相似文献   
992.
Background  The muscularis propria of the stomach is histologically divided into three layers; namely, the innermost oblique, the inner circular, and the outer longitudinal layers. In patients with gastric cancer the depth of tumor invasion has been reported to correlate with lymph node metastasis and prognosis. However, it is unclear whether the depth of tumor invasion in the muscularis propria has an effect on lymph node metastasis and prognosis. Methods  Fifty-nine gastric cancer patients with muscularis propria invasion were analyzed retrospectively. These patients were divided into two groups, the inner group, with invasion up to the inner circular layer; and the outer group, with invasion beyond the inner circular layer. The relationships between tumor invasion and clinicopathological factors and survival were evaluated. Results  Of the 59 patients, 34 were classified as the inner group, and 25 were classified as the outer group. The inner group had a significantly lower probability of lymph node metastasis (P = 0.0053) and a significantly better overall cancer-specific survival (P = 0.017) than the outer group. Conclusion  Gastric cancers with muscularis propria invasion had heterogeneous prognoses according to the tumor depth in the muscularis propria layers.  相似文献   
993.
Summary In an 18-year-old male with Eisenmenger syndrome cyanosis and erythrocytosis were increasing. The erythrocytosis diminished following oral bunazosin and phlebotomy was not needed during the treatment. When bunazosin was stopped, the erythrocytosis increased, but when it was resumed, the erythrocytosis and general fatigue diminished.  相似文献   
994.
We examined the antitumor effects of recombinant interferon-gamma (IFN-gamma) and tumor necrosis factor (TNF) on cervical adenocarcinoma cell lines, in vitro and in vivo. Four of five cell lines showed a high sensitivity to IFN-gamma, in vitro. One of five cell lines showed a remarkable sensitivity to TNF, in vitro. Only one cell line resistant to both IFN and TNF was derived from a well-differentiated adenocarcinoma of endocervical type. Experiments using nude mice bearing transplanted tumors revealed that these cytokines were also effective against tumors in vivo. All these observations suggest that IFN-gamma or TNF can have positive effects in the treatment of patients with adenocarcinoma of the uterine cervix.  相似文献   
995.
Eighteen patients with advanced or recurrent carcinoma of the cervix were treated with a combination of peplomycin, vincristine, mitomycin-C, and cisplatin (POMP). Ten of the 16 evaluable patients (63%) responded, including 4 with a complete response. Median duration of the response was 7 months. Two of 6 with intrapelvic recurrent tumors responded to some extent following intraarterial infusion. The subcutaneous infusion of peplomycin was well accepted by the patients. Toxicity was tolerable. This regimen seemed to be one of the regimens which should be considered for the advanced or recurrent cervical cancer.  相似文献   
996.
A 56-year-old Japanese man in whom a descending colon carcinomahad been resected underwent a high orchitectomy for metastaticepididymis from the colon. Metastatic carcinoma from the digestiveorgans to the spermatic cord (SC) and/or the intrascrotal contents(ISC) is rare. Fifty-four Japanese patients with metastasisfrom the digestive organs to the SC and/or the ISC were analyzed.The most frequent primary site was the stomach and the mostfrequent metastatic site was the spermatic cord. Our patientwas the first to exhibit metastasis from the colon to the epididymis.A primary site was identified in 24 patients subsequent to themetastatic tumor. Twenty patients had other organ metastatis.The prognosis for SC and/or ISC metastasis patients is poor.Our patients has survived for 18 months following his orchitectomywith no other organ metastasis (31 months after the primaryoperation). In our patient, monoclonal estrogen receptor stainingwas negative; however, further study must be undertaken.  相似文献   
997.
A comparative study of a new tumour marker, CA242, and CA19-9 was conducted with special reference to their diagnostic usefulness in pancreatic cancer. CA242 showed sensitivity similar to that of CA19-9 for overall cases and early cases (stage I tumour) of pancreatic cancer. For other malignancies, the positive rates of CA242 were lower than those of CA19-9 except for colorectal cancer. An important characteristics of CA242 was that it was only slightly and infrequently elevated in the sera of patients with benign diseases such as chronic pancreatitis, chronic hepatitis and liver cirrhosis. This characteristic was more apparent in the patients with benign obstructive jaundice, indicating that the serum level of this marker was scarcely affected by cholestasis. Using cut-off levels corresponding to a 90% specificity, the clinical results obtained with CA242 in the diagnosis of pancreatic cancer were similar to those obtained with CA19-9, except that CA19-9 was falsely negative in some patients with early-stage pancreatic cancer. These findings suggest the usefulness of this marker for screening pancreatic cancer in patients on their first hospital visit. However, CA242 was found to be influenced by the Lewis blood group system. This unfavourable result is attributed to the C241 catcher antibody of this assay system, which has almost the same epitope specificity as the C50 and the NS19-9 monoclonal antibodies. In conclusion, CA242 is superior to CA19-9 in diagnosing pancreatic cancer by virtue of its higher specificity.  相似文献   
998.
999.
We conducted a prospective study to evaluate the significanceof serum neuron-specific enolase (NSE) as a predictor of relapseof small cell lung cancer (SCLC). Patients entered into thestudy were drawn from those who had shown a complete or partialresponse to first-line chemotherapy with a concurrent declinein the NSE level to less than 10 ng/ml. When the serum NSE levelincreased to more than 15 ng/ml, the patient was restaged onthe basis of clinical, radiological, and bronchoscopic examinations.During the period from August 1988 to December 1990, 57 patientswith SCLC were enrolled and followed up until May 1992; Of thesepatients, 45 had clinical relapses, and 14 (31%) of them showeda clear elevation of the serum NSE level prior to the clinicalrecognition of relapse. Although one false-positive case wasnoted, this involved only a transient elevation of the NSE level.In patients who showed increased NSE levels, the relapses occurredin more difficult to detect silent sites such as the adrenalgland, liver, and deep lymph nodes. In addition, the percentageof patients demonstrating high NSE levels who were able to benefitfrom salvage chemotherapy was higher than for those who didnot (P<0.05). Our results indicate that serial NSE measurementsare useful for the early prediction of SCLC relapse and shouldhelp to facilitate early administration of salvage chemotherapyfor affected patients.(P<0.05)  相似文献   
1000.
Two phase I trials of irinotecan (CPT-11) in combination with cisplatin were conducted. In both cases, the dose-limiting toxicities were leukopenia and/or diarrhea. During these trials the pharmacokinetics of CPT-11 and its active metabolite, 7-ethyl-10-hydroxycamptothecin (SN-38), were investigated to evaluate the relationship between pharmacokinetic parameters and diarrhea, since this is an unpredictable and severe toxicity of combination chemotherapy using CPT-11 and cisplatin. Twenty-three previously untreated patients with advanced lung cancer were evaluated in the pharmacokinetic study. Ten patients received CPT-11 at 80 or 90 mg/m2 plus cisplatin at 60 mg/m2. The other 13 patients received CPT-11 at 80 or 90 mg/m2 plus cisplatin at 80 mg/m2 with the granulocyte colony-stimulating factor support (2 μg/kg × 16 days). CPT-11 was given as a 90-min intravenous infusion on days 1, 8, and 15. Cisplatin was given on day 1. The pharmacokinetics of CPT-11 and SN-38 were analyzed on day 8 during the first course of treatment. The maximum tolerated dose of CPT-11 was 90 mg/m2 in both phase I trials. The severity of diarrhea was best correlated with the peak plasma concentration of SN-38 among the pharmacokinetic parameters tested. In addition, patients with a plasma SN-38 level > 12.4 ng/ml at 1.75 h after the start of CPT-11 infusion had a higher incidence of Eastern Cooperative Oncology Group grade 3–4 diarrhea than those with a lower SN-38 level ( P =0.0003). Stepwise logistic regression analysis identified the SN-38 concentration as a significant contributor to the development of diarrhea ( P =0.0021). We conclude that there is a clear relationship between the SN-38 concentration and diarrhea during chemotherapy with CPT-11 plus cisplatin.  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